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Trim: 247mm × 174mm Top: 12.653mm Gutter: 16.871mm
CUUK2487-FM CUUK2487/Kitayama ISBN: 978 1 107 02616 2 November 11, 2013 15:8
Optical Code Division Multiple Access
A Practical Perspective
This book is a comprehensive guide to optical fiber communications, from the basic
principles to the latest developments in OCDMA for next-generation Fiber-to-the-Home
(FTTH) systems. Part I starts with the fundamentals of light propagation in optical fibers,
including multiple access protocols, and their enabling techniques. Part II is dedicated to
the practical characteristics of next-generation Fiber-to-the-Home (FTTH) technology.
It covers the key building blocks of OCDMA, devices such as optical encoders and
decoders, signal impairment due to noise, and data confidentiality, a unique property of
OCDMA. This is followed by a discussion of hybrid system architectures with TDM
and WDM and practical aspects such as system cost, energy efficiency and long-reach
passive optical networks. Featuring the latest research, with cutting-edge coverage of
system design, optical implementations, and experimental demonstrations in testbeds,
this text is ideal for students, researchers and practitioners in the industry seeking to
obtain an up-to-date understanding of optical communication networks.
Ken-ichi Kitayama has been a Professor at the Department of Electrical, Electronic, and
Information Engineering at Osaka University, Japan since 1999. He has published over
270 papers in refereed journals, and holds more than 40 patents. He is a Fellow of the
IEEE and a Fellow of IEICE, Japan.

Optical Code Division
Multiple Access
A Practical Perspective
KEN-ICHI KITAYAMA
Osaka University, Japan

University Printing House, Cambridge CB2 8BS, United Kingdom
Published in the United States of America by Cambridge University Press, New York
Cambridge University Press is part of the University of Cambridge.
It furthers the University’s mission by disseminating knowledge in the pursuit of
education, learning and research at the highest international levels of excellence.
www.cambridge.org
Information on this title: www.cambridge.org/9781107026162
C
Ken-ichi Kitayama 2014
This publication is in copyright. Subject to statutory exception
and to the provisions of relevant collective licensing agreements,
no reproduction of any part may take place without the written
permission of Cambridge University Press.
First published 2014
Printed in the United Kingdom by TJ International Ltd., Padstow, Cornwall
A catalog record for this publication is available from the British Library
Library of Congress Cataloguing in Publication data
Kitayama, Ken-Ichi.
Optical code division multiple access : a practical perspective / Ken-ichi Kitayama.
pages cm
Includes bibliographical references and index.
ISBN 978-1-107-02616-2 (hardback)
1. Optical fiber communication. 2. Code division multiple access. I. Title.
TK5103.592.F52K57 2014
621.38275 – dc23 2013034909
ISBN 978-1-107-02616-2 Hardback
Cambridge University Press has no responsibility for the persistence or accuracy of
URLs for external or third-party internet websites referred to in this publication,
and does not guarantee that any content on such websites is, or will remain,
accurate or appropriate.

To my wife, Michiyo, my daughters, Hiromi and Midori,
and my friends, Johan and Andrew

Contents
Preface page xi
Acknowledgments xiii
1 Introduction 1
1.1 Broadband service trend 1
1.2 Historical perspective of optical fiber communications 4
1.3 Optical transmission systems 4
1.4 Optical networks 15
1.5 Access networks 23
1.6 Local area networks 29
Problems 30
Part I 31
2 Optical multiple access systems 33
2.1 Passive optical network 33
2.1.1 Technology roadmap 33
2.1.2 Current PON 35
2.1.3 Practical aspects 41
2.2 Multiple access techniques 47
2.2.1 Time division multiple access 47
2.2.2 Wavelength division multiple access 49
2.2.3 Hybrid of wavelength and time division multiple access 54
2.2.4 Orthogonal frequency division multiple access 55
2.3 Power saving operation 61
Problems 64
3 Light propagation in optical fibers 65
3.1 Loss 65
3.2 Waveguide mode 68
3.3 Single-mode fiber 73
3.4 Two-mode fiber 79

viii Contents
3.5 Coupled-mode theory 84
3.5.1 Co-directional coupling 85
3.5.2 Contra-directional coupling 87
3.5.3 Distributed Bragg reflection laser diode 90
3.6 Dispersion 91
3.7 Pulse broadening 95
3.8 Dispersion compensation 101
Appendix 3.1 103
Appendix 3.2 103
Appendix 3.3 104
Appendix 3.4 105
Problems 105
4 Fundamentals of transmission systems 107
4.1 Detection theory 107
4.2 Modulation 110
4.2.1 Modulation formats 110
4.2.2 On-off-keying modulation 112
4.2.3 Electro-optic effect 115
4.3 Additive noise 118
4.3.1 Shot noise 118
4.3.2 Thermal noise 119
4.3.3 Optical amplifier noise 119
4.4 Quantum limit of OOK direct detection 121
4.5 Bit error rate of OOK transmission systems 123
4.6 Coherent detection of OOK transmission systems 124
4.7 Phase-shift-keying modulation transmission systems 126
4.7.1 Binary phase-shift-keying modulation 126
4.7.2 M-ary phase-shift-keying modulation 127
4.7.3 Bit error rate of binary phase-shift-keying 131
4.8 Stimulated Brillouin scattering 133
Appendix 4.1 135
Problems 137
5 Enabling techniques 139
5.1 Star coupler 139
5.2 Broadband light source 140
5.2.1 Mode-locked laser diode 140
5.2.2 Supercontinuum light source 146
5.3 Optical time-gating 147
5.4 Optical thresholding 151
5.5 Erbium-doped fiber amplifier 151
5.5.1 Operation principle 152
5.5.2 Pump scheme 154

Contents ix
5.6 Burst-mode 3R receiver 155
5.7 Colorless technique 158
Problems 162
Part II 163
6 OCDMA principles 165
6.1 Spread spectrum communication 165
6.2 Wireless CDMA versus optical CDMA 167
6.3 Optical decoding based upon correlation 172
6.4 Early stage of OCDMA 173
6.4.1 Coherence of the light source 173
6.4.2 Coherence multiplexing 175
6.4.3 Coherent versus incoherent OCDMA 176
6.4.4 Asynchronous versus synchronous OCDMA 178
6.5 Signal impairment 180
6.5.1 Evaluation of system performance 180
6.5.2 Chip rate detection 181
6.5.3 Bit rate detection 185
7 Optical encoding and decoding 188
7.1 Code sequences 188
7.1.1 Prime code 188
7.1.2 Gold code 189
7.2 Optical code sequences 193
7.2.1 On-off-keying code 193
7.2.2 Phase-shift-keying code 194
7.3 Optical encoders and decoders 195
7.3.1 Superstructured fiber Bragg grating encoder and decoder 195
7.3.2 Multiport encoder and decoder in arrayed waveguide
grating configuration 208
7.3.3 Correlation between heterogeneous combination of multiport
and SSFBG encoder and decoder 219
8 Data confidentiality 223
8.1 Security architecture for systems provisioning end-to-end
communications 223
8.2 Security threats to a PON 226
8.3 Bit ciphering versus block ciphering 227
8.3.1 Bit ciphering 227
8.3.2 Block ciphering 232
8.4 Data confidentiality of OCDMA-PON 235
8.5 Steganographic security enhancement 236

x Contents
8.6 M-ary OCDMA 236
8.6.1 Principle of operation 236
8.6.2 Implementation of 16-ary OCDMA 238
8.6.3 Scaling of the M-ary count 241
9 Testbeds of OCDMA and hybrid systems 251
9.1 OCDMA testbed 251
9.2 Hybrid OCDMA systems 255
9.2.1 TDM-OCDMA-PON system 255
9.2.2 WDM-OCDMA-PON system 269
9.2.3 TDM-WDM-OCDMA-PON system 273
9.3 40 Gb/s OCDMA systems 277
9.3.1 Multiport encoder and decoder configuration 278
9.3.2 SSFBG and mutiport encoder and decoder configuration 280
9.4 Space OCDMA 282
9.4.1 Space encoding and decoding 283
9.4.2 Experimental demonstration 288
9.4.3 Multicore erbium-doped image fiber amplifier 291
10 Practical aspects 297
10.1 Capacity, cost and power consumption of hybrid PONs 297
10.1.1 Total capacity 297
10.1.2 Cost 301
10.1.3 Power consumption 304
10.2 Applications of optical codes in optical networks 305
10.2.1 Optical packet switching 306
10.2.2 Multi-granularity optical path switching 311
10.3 Faults and troubleshooting 315
10.3.1 Possible scenario of faults in PON 315
10.3.2 Testing and testing equipment 316
10.3.3 Case studies of faults 318
10.4 Safety to the human body and systems 321
10.4.1 Safety to the human body 321
10.4.2 Fiber fuse 322
References 326
Index 338

Preface
Between 2000 and the end of 2011, almost two thirds of subscribers to the plain old
telephone service (POTS) in Japan switched to the broadband service, and half of
the subscribers to the broadband service are now connected to the Fiber-to-the-Home
(FTTH) system. The rate of increase in new FTTH subscriptions is already showing
signs of leveling off. This is the case not only in Japan but also in the rest of the world
where the same trend will be observed in the near future as the FTTH system becomes
widespread.
This rapid growth of the broadband service, along with the emerging need for back-
hauling the huge data traffic of mobile phones, will eventually trigger the problem of
“capacity crunch” in long-haul optical fiber transmission systems. The capacity crunch
happens when the data traffic to be transferred from one end of the network to the other
end overflows the total capacity of optical fiber cables deployed on the planet. Only
incessant innovation of the transmission system and optical network technologies can
solve this problem. Technologies of optical fiber transmission systems currently under
intense development include digital coherent transmission and the multiplexing tech-
nique of space division multiplexing (SDM). There are two approaches to SDM: one
is via a multicore fiber which has a number of cores embedded in the cladding of the
fiber, and the other is mode division multiplexing (MDM) via a multimode fiber which
supports more than one waveguide mode. Digital coherent transmission has the capabil-
ity of overcoming the disadvantages of multi-level phase-shift-keying modulated optical
signals, caused by chromatic and polarization dispersions, with the aid of powerful dig-
ital signal processing (DSP). This is a result of rapid progress in silicon complementary
metal oxide semiconductor (CMOS) LSI technology, underpinned by Moore’s law. In
this way, the limitations in the transmission distance and the bit rate have been overcome,
although the system is not perfect.
Such advanced technologies developed for backbone networks will be adopted in
metro/access networks after a few or ten years as their costs go down. For example, the
first commercial 10 Gb/s system was deployed in a long-haul transmission line between
Tokyo and Osaka in Japan in 2003, and now the commercial 10 Gb/s passive optical
network (PON) is almost ready to be deployed. Thus, current optical access networks
will soon evolve to the next-generation (NG) PON with higher bit rate and longer reach.
A forum of the world telecommunications industries has studied a roadmap of the NG-
PON: one system is NG-PON1 aiming at evolutionary growth, which supports “brown
field” deployment, and the other is NG-PON2 aiming at revolutionary growth, supporting

xii Preface
a “green field” deployment. Note that in the brown field deployment newly introduced
technology has to coexist with ongoing PONs, while the green field deployment can
be disruptive, with little requirement for coexistence with other PONs. At the time of
writing, the objective of NG-PON2 has been altered from revolutionary to evolutionary.
However, this will not be the end of the NG-PON scenario because there remain plenty
of green fields on the globe where a revolutionary technology might be deployed from
the beginning. Therefore, NG-PON2 in a true sense is likely to appear on the scene as
post NG-PON2.
Optical code division multiple access (OCDMA) has been emerging as a promising
technology of choice for the NG-PON. OCDMA has unique capabilities such as fully
asynchronous transmission, low latency access, and soft capacity on demand. Another
advantage is inherent data confidentiality. Messages are encoded at the transmitter and
can be recovered only by the authorized subscriber, who knows the optical code.
This book should be valuable to both students at universities and mid-career profes-
sionals in the telecom industry. I reference very recent research progress as much as
possible, which will be useful to researchers in this field. This book can be added to
collections as a popular item in university libraries and RD centers of industry. Parts
I and II in this book serve different purposes. Part I is devoted to the fundamental tech-
nology underlying optical fiber communications. Part II offers an extensive coverage of
a wide variety of technologies, relevant to OCDMA-PON systems. Those who are new
to this field would be better to start with Part I and then proceed to Part II. Part II is for
those who have a solid background in optical communication and networks but need to
understand the practical perspectives and future-proof technology of Fiber-to-the-Home
(FTTH) systems. To aid in teaching and learning the material, selected problems are
provided at the ends of the chapters in Part I.
The book consists of ten chapters with the following organization. In Part I, Chapter 1
offers an introduction to optical fiber communications and networks. Chapter 2 describes
the basics of PONs and multiple access techniques. Chapter 3 describes how light prop-
agates in an optical fiber and what the guided modes are. In Chapter 4 the model and
building blocks of optical transmission systems as well as the methodology of perfor-
mance evaluation are described. Chapter 5 deals with enabling techniques of OCDMA.
In Part II, Chapter 6 defines OCDMA, including its roots, system classification, and
noise unique to OCDMA. In Chapter 7 various techniques of optical encoding and
decoding are described. Chapter 8 covers data confidentiality which is inherently pro-
vided with OCDMA. Chapter 9 offers an extensive coverage of experimental demon-
strations done by the author’s group in the OCDMA testbeds, including hybrid systems
of TDM-OCDMA, WDM-OCDMA, and WDM-TDM-OCDMA PONs, followed by
space-OCDMA. Chapter 10 includes a comparison of the cost and the power consump-
tion of various PON systems, applications of optical code labeling in optical networks,
and practical aspects of PON such as testing and equipment, and safety issues with
respect to exposure of the human body.

Acknowledgments
My first and foremost gratitude is due to my colleagues at the Communications Research
Laboratory, CRL, the Ministry of Posts and Telecommunications (renamed the National
Institute of Technology, NICT), Naoya Wada, Xu Wang presently of Heriot-Watt Univer-
sity, Moriya Nakamura presently of Meiji University, Hedeyuki Sotobayashi presently of
Aoyama Gakuin University, Nobuaki Kataoka formerly with NICT, Toshio Kuri, Yoshi-
nari Awaji, and Satoshi Shimizu for long-term collaboration since 1995. I would like to
express my sincere thanks to Gabriella Cincotti, Rome Tre University, also for long-term
collaboration. It was my good fortune to work under my boss at CRL, Tadashi Shiomi,
presently at Yokohama National University. Without his generous support, research
activity in OCDMA would never have taken off so smoothly.
I also thank Akira Himeno, Masayuki Okuno, and Takashi Saida of NTT Electron-
ics Corp., Takashi Mizuochi, Jun-ichi Nakagawa, Naoki Suzuki, and Satoshi Yoshima
of Mitsubishi Electronic Corp., Yoshihiro Terada, Akira Sakamoto, Koji Omichi, and
Ryozo Yamauchi of Fujikura, Akihiko Nishikki of OKI Electric Industry Corp., Naoto
Yoshimoto, Shunji Kimura, Shin Kaneko, Noriki Miki, and Hideaki Kimura of NTT
Access Network Service Systems Laboratories, Yosihiro Tomiyama of Aisthesis Corp.,
and Yasuyuki Kato, Tadatoshi Tanifuji, and Masahiro Ikeda formerly of NTT Labs
for their collaboration. I would like to thank my colleagues at Osaka University, Aki-
horo Maruta, Yuki Yoshida, and Takashi Kodama, for their inspiring discussions and
continuous support.
I am grateful to the following individuals who have provided me with technical
materials: Yoshio Itaya, Honchul Ji, Kunio Kokura, Yoichi Maeda, Hideo Miyahara,
Kunio Mori, Toshikazu Sakano, Hiromichi Shinohara, Shin-ichi Todoroki, Yoshito
Shuto, Moshe Tur, and Shuichi Yanagi. I have also greatly benefitted from the help
of my students at Osaka University. I thank Masaya Nakazawa, Ryosuke Matsumoto,
and Daisule Hisano for executing computer plots of figures. The figures were drawn by
Ai Yamamoto with inimitable care.
And last but not at least, my sincere thanks are due to my mentor, the Hon-
orary Professor Nobuaki Kumagai, who guided me in such an exciting research
field of optical communications at Osaka University when I was an undergraduate
student.
Finally, my special thanks are extended to Phil Mayler, Publishing Director and Mia
Balashova, Publishing Assistant of Cambridge University Press for their tremendous

xiv Acknowledgments
effort in organizing the logistics of the book, including the editing and promotion that
make this publication happen.
Ken-ichi Kitayama
Osaka, Japan
Author Biography
Ken-ichi Kitayama has been a Professor in the Department of Electrical, Electronic
and Information Engineering, Graduate School of Engineering, Osaka University, Japan
since 1999. He received the M.E. and Dr.Eng. degrees in communication engineering
from Osaka University in 1976 and 1981, respectively. In 1976 he joined the NTT
Laboratories. In 1982–1983, he spent a year as a visiting Research Fellow under the
supervision of Professor Shyh Wang and Professor T. Kenneth Gustafson at the Uni-
versity of California, Berkeley. From 1995 to 1999, he was with the Communications
Research Laboratory, CRL, the Ministry of Posts and Telecommunications (currently
known as the National Institute of Information and Communications Technology, NICT),
Japan.

CUUK2487-01 CUUK2487/Kitayama ISBN: 978 1 107 02616 2 November 10, 2013 10:9
1 Introduction
1.1 Broadband service trend
Internet traffic has been expanding exponentially with the rapid growth in cloud com-
puting data, smart phone voice and videoconferencing, and streaming contents of IP
TV, video sharing applications such as YouTube, and 3D TV, as shown in Fig. 1.1 [1].
In 2012 global IP traffic was expected to exceed 40 exa-bytes per month, of which
consumer IP traffic is the largest portion. The growth in Internet traffic is driving large
carriers to prepare to provide enough bandwidth to meet market demand. According to
the forecast [2], the compound annual growth rate (CAGR) of Internet traffic is 32% in
six years in the period 2010–2015. On the other hand, the profits of telecommunication
carriers are staying constant or even decreasing as the profitable old telephone service is
being switched to the voice over IP (VoIP) service. Therefore, there is strong motivation
for the carriers and service providers to reduce their capital expenditure (CAPEX) by
fully exploiting the capacity of their existing installed optical fiber cables without the
costly deployment of new cables.
The number of broadband subscribers is increasing rapidly all over the world, exceed-
ing 600 million in 2010. The broadband services are provided either by a wired infras-
tructure such as Fiber-to-the-Home (FTTH), digital subscriber line (DSL), and cable
modem (CATV) or fixed wireless access (FWA). In particular, the increase in FTTx
subscribers has been remarkable in recent years. The line bit rate ranges from a few tens
of kb/s to Gb/s, and even higher, and the broadband service includes so-called “triple
play” of data communication, voice over IP (VoIP), and video or TV broadcasting. As
the broadband service penetrates deep into residential areas in developing countries in
Asia, Eastern Europe, and South America, the traffic volume will continue growing
exponentially, and this has a tremendous impact on the backbone network.
From Fig. 1.2 one can see that the number of broadband subscribers in Japan has
increased rapidly to 30 million at the end of 2010, with almost two thirds of fixed
telephone subscribers having switched to the broadband service [3]. The broadband
subscribers are broken up into 14.4 million FTTH, 11.6 million DSL, and 4.1 million
CATV. It is interesting to observe that the DSL penetrated faster than FTTH in the earlier
stage, but later the number of DSL subscribers decreased while the number of FTTH
subscribers was picking up slowly, with the crossover occurring at the end of 2008. The
monthly charges of the broadband service in Japan are plotted as a function of the bit

2 Introduction
Figure 1.1 Global Internet traffic growth in the world [2]. C
Reprinted by permission of Cisco.
Figure 1.2 Number of subscribers of the broadband service in Japan [3]. C
Reprinted by
permission of the Ministry of Internal Affairs and Communications.

1.1 Broadband service trend 3
Figure 1.3 Monthly charge versus bandwidth of the broadband service in Japan [4], by courtesy
of T. Sakano.
Figure 1.4 Broadband subscribers in the world for 2006–2009 [5]. C
POINT topic by permission.
rate in Fig. 1.3 [4]. The charge has been decreasing rapidly to below 1 USD/Mbps as the
bit rate has increased higher than 100 Mb/s.
By contrast, this trend is not the case in developing countries. As a consequence, the
overall number of DSL subscribers in the world is still dominant over the number of
FTTH subscribers, as seen in Fig. 1.4 [5]. In the top ten countries in 2010, China has
the largest number of subscribers, 127 billion, followed by 857 million in the USA and
Japan, 261 million in Germany, and 209 million in France, UK, Russia, South Korea,
Brazil, and Italy.

4 Introduction
1.2 Historical perspective of optical fiber communications
Without the two inventions of the laser and the optical fiber, the optical fiber commu-
nications technology would not exist today. These two inventions were awarded with
Nobel Prizes in Physics.
The Nobel Prize in Physics 1964 was divided, one half awarded to Charles Hard
Townes, the other half jointly to Nicolay Gennadiyevich Basov and Aleksandr
Mikhailovich Prokhorov. The citation reads “for fundamental work in the field of
quantum electronics, which has led to the construction of oscillators and amplifiers
based on the maser-laser principle.”
The Nobel Prize in Physics 2009 was divided, one half awarded to Charles Kuen Kao.
The citation reads “for groundbreaking achievements concerning the transmission
of light in fibers for optical communication.”
Looking back at the history of glass, shown in Fig. 1.5 [6], the glass made by the ancient
Egyptians in 1 BC was sufficiently transparent in the region of visible wavelengths. In
1966 Dr. Kao, the 2009 Nobel Prize laureate for Physics, first proposed the concept of
cladded glass fibers as a “new form of communication medium” and in his seminal paper
he predicted that the fiber loss could be reduced to as low as 20 dB/km [7]. Today’s
float glass used for window glass has typically a loss of a few dB/mm. The past forty
years have witnessed a significant reduction in loss of silica-based optical fibers and the
transition of the transmission window into the near infrared, as shown in Fig. 1.6 [8].
Since a record loss of 17 dB/km for silica fiber reported in 1970, it has taken only fifteen
years for the attenuation to be reduced to 0.2 dB/km [9].
1.3 Optical transmission systems
There are two basic multiplexing and demultiplexing techniques, time division multi-
plexing (TDM) and wavelength division multiplexing (WDM). Multiplexing allows a
number of channels to be established in a one-bit time duration in an optical fiber, and it
is motivated by the economical reason that the installation of new optical fiber cables is
costly, and there is a need to exploit fully the potential transmission capacity of existing
fibers. Figure 1.7 shows schematically current mainstream techniques, TDM and WDM,
along with optical division multiplexing (OCDM). TB denotes the one-bit time duration.
In TDM a time slot is divided into the channel count, N slots, and one data-bit pulse is
squeezed into the time duration TB/N. Since WDM uses wavelengths as the channels,
the time duration of the slot is maintained at TB. In OCDM a channel is assigned with
a unique temporal waveform. OCDM is a multiplexing and demultiplexing technique,
and it will be discriminated from optical code division multiple access (OCDMA). More
details of OCDMA will be described in Section 1.5.
TDM and WDM are compared in Fig. 1.8. In TDM, shown in Fig. 1.8(a), three
time slots are multiplexed in the time TB using a switch at the transmitter, and after

3000
BC
1000
AD
1900
YEAR
OPTICAL
GLASS
OPTICAL
LOSS
(dB/km)
OPTICAL
FIBER
96
0.1
1.0
10
102
103
104
105
106
107
5
10
%
TRANSMISSION/km
1
10−10
10−100
VENETIAN
EGYPTIAN
1966 1979 1983
Figure 1.5 Historical loss reduction of glass versus year [6]. C
Reprinted by permission of IEEE.
electrical-to-optical (EO) conversion the multiplexed optical signal is transmitted in an
optical fiber. At the receiver the TDM signal is demultiplexed into a separate channel
using a switch after optical-to-electrical (OE) conversion. Obviously, strict time syn-
chronization between the transmitter and receiver is required, and the electrical switch
has to operate at a speed of TB/3, three times faster than the one-bit time duration. As
the electrical switch is used for multiplexing and demultiplexing, this type of TDM is
sometimes referred to as ETDM, in order to distinguish it from optical TDM (OTDM).
Multiplexing and demultiplexing of OTDM are performed using a high-speed optical
switch. In WDM, shown in Fig. 1.8(b), data from three channels after EO conversion into
different wavelengths are multiplexed using a wavelength multiplexer at the transmitter

6 Introduction
Figure 1.6 Silica optical fiber loss versus year [8]. C
Reprinted by permission of Ohmsha.
Figure 1.7 Multiplexing techniques: TDM and WDM, and OCDM.
and transmitted in an optical fiber. At the receiver the WDM signal is demultiplexed
using a wavelength demultiplexer into a separate channel and converted into electri-
cal signals. Multiplexing and demultiplexing of WDM are performed optically using
passive optical devices, and therefore the data rate is not restricted by the speed of the
multiplexer and demultiplexer, unlike TDM.
To cope with demands for the increase in bandwidth, optical fiber communications
technology has been continuously evolving and has gone through three generations over
three decades. The evolution of the transmission performance of optical fiber commu-
nications, the product of total transmission capacity per fiber and the distance, is shown

Figure 1.8 (a) Multiplexing and demultiplexing of TDM and (b) multiplexing and demultiplexing
of WDM.
in Fig. 1.9 [10]. Note that the solid and white circles, respectively, denote commercial
systems in operation and experimental demonstrations in laboratories. It is interesting
to see that commercial system deployment follows five or six years behind the labora-
tory experiments. A commercial optical fiber transmission system using a graded-index
multimode fiber, F-100M and F-32M, at a wavelength of around 1300 nm, was the first
system to be launched in 1981 in Japan. It was followed by commercial deployment of
the single-mode fiber in F-400M at a wavelength of 1300 nm in 1983, and the operation
wavelength was shifted to 1550 nm in 1984, resulting in extension of the repeater span
from 20 km to 80 km. During three decades the bit rate per wavelength has increased

8 Introduction
Figure 1.9 Evolution of optical fiber transmission technology: product of transmission capacity
and distance versus year. Updated after [10].
by a factor of 103
from 100 Mb/s to 100 Gb/s, and the product of the bit rate and the
transmission distance has increased by a factor of 106
as seen in Fig. 1.9. Some of
the major laboratory experiments have exceeded 105
Pb/s km, which typically range
between 100 Tb/s over 1000 km and 10 Tb/s over 10,000 km. On the other hand, the
deployment of commercial systems in public telecommunication networks has evolved
steadily up to 40 Gb/s with the total capacity per fiber of a few Tb/s. The commer-
cial deployment of a digital coherent 100 Gb/s long-haul system is expected in early
2013.
For possible solutions to the emerging issue of capacity crunch, other multiplexing
techniques such as space division multiplexing (SDM) have been revisited. As shown
in Fig. 1.10 [11], there are two approaches. One approach is via a multicore fiber with
a number of cores embedded in cladding of the fiber [12]. A record total transmission
capacity up to 1.0 Pb/s using 11-core fiber, 380 Gb/s, 222-WDM has been reported, but
the transmission distance is limited to 53 km as shown by the triangle in Fig. 1.9 [13].
However, unprecedented challenges are fiber splicing, optical amplification, crosstalk
reduction between cores, and light coupling. The other approach is mode division multi-
plexing (MDM) via a multimode fiber which supports more than one waveguide mode.
The modes can be exploited as independent channels, as shown in Fig. 1.11. In prac-
tice, for long distance optical communication, mode coupling between the independent
channels is inevitable. According to information theory, however, the coupling between
the channels does not necessarily cause a loss of capacity as long as this coupling can be

Figure 1.10 Space division multiplexing (SDM): (a) multicore fiber and (b) multimode fiber [11].
C
Reprinted by permission of NTT.
Figure 1.11 Space division multiplexing (SDM) transmission system using MIMO technique
[12]. C
described as a unitary transformation. For simplicity, compare two-mode transmission
in a fiber with single-mode transmission at the same total input power. The transmission
capacity of the two-mode transmission is 2 log2(1 + 1/2 S/N) and gains to some extent
over the capacity log2(1 + S/N) of the single-mode transmission. This concept of par-
allel transmission is well established in wireless communication, where multiple-input
multiple-output (MIMO) techniques have been widely used to increase the reach and
capacity of wireless links [14]. Recently, MIMO has been introduced in optical fiber

10 Introduction
Figure 1.12 Fiber fusion splice machine. C
Reprinted by courtesy of Fujikura Ltd.
communications. An experiment has demonstrated 20 GSymbol/s quadrature-phase-
shift-keying (QPSK) signals transmission over a 6 × 6 MIMO channel over a 1200 km
differential-group delay compensated few-mode or two-mode fiber [15]. More details of
few-mode (two-mode) fibers are described in Section 3.4.
Let us review the progress in optical fiber and device technologies since the mid-1970s.
The first generation was characterized by electrical time division multiplexing (ETDM)
in the early 1980s. A single-frequency laser such as a distributed feedback (DFB) laser
diode and distributed Bragg reflector (DBR) laser diode along with a single-mode fiber
(SMF) were key enablers to realize multi-gigabit rate transmissions. Believe it or not,
it was doubtful at that time whether a single-mode fiber having only about 5 µm radius
core could be connected with low loss. Having achieved an optical fiber loss below
0.2 dB/km, a low-loss splice was regarded as a stringent requirement. This problem
was solved using a well-engineered automatic fusion splice machine and a fiber cutter.
The fusion splice machine melts the end faces of the fibers at a temperature of about
1500 °C by arc discharge between electrodes, and splices by pushing forward two
fibers. It required skilful fine manual position alignment in three directions between the
fibers. However, an automatic fusion splice machine was soon developed in which
the positioning mechanism uses a video monitor. This machine, shown in Fig. 1.12,
works automatically and allows the worker in the field plant to cut and position fibers
without any particular skill. In this way a fusion splice can be completed in 15 seconds.
The typical value of splice loss of the single-mode fiber is 0.03 dB.

Figure 1.13 WDM grid.
In the second generation in the late 1990s, an optical amplifier had a tremendous
impact on the cost reduction per channel as well as the extension of the transmission
distance. In particular, an erbium-doped fiber amplifier (EDFA) played a key role in
extending the transmission distance. The EDFA has a large gain of 30 dB and also
covers the most transparent window of fused silica fiber, the conventional (C)- and long
(L)-bands of the spectral region of 11 THz, ranging from 1530 nm to 1625 nm as shown
in Fig. 1.13. The first amplifier was demonstrated in early 1964 using Nd3+
-doped
barium crown glass [16]. Another major advance was achieved with the operation of
end-pumped glass-clad Nd3+
-doped silica fiber lasers [17]. A decade later, low threshold,
high-slope-efficiency Nd3+
-doped fiber lasers were demonstrated [18]. One problem was
the pumping wavelength. First, the 515 nm line of an argon laser was used as the pumping
wavelength, and later developments included the second line at 980 nm and the third
line at 1480 nm. Soon laser diodes became available for pumping both wavelengths. In
parallel, WDM was introduced to increase further the transmission capacity per fiber by
using a number of colored channels. The EDFA together with WDM technology has had
a crucial economic impact by reducing drastically the cost of a long-haul transmission
system, because a number of WDM channels can be amplified simultaneously with a
single EDFA. For example, an EDFA can amplify 80 WDM channels in the C-band
with a frequency interval of 50 GHz. More details of the EDFA will be described in
Section 5.5.
In the third generation, the challenge has been to increase further the transmission
capacity. Remember that there is a strict requirement that the signal bandwidth be
squeezed into the 50 GHz frequency interval to maintain existing WDM systems with
the least modification. This will keep the capital expenditure (CAPEX) as low as pos-
sible for the telecom carriers. For better spectral efficiency, wireless communication
technologies came into play in optical fiber communications, such as multi-level phase-
and/or amplitude-shift keying modulation formats. A commercial DWDM 40 Gb/s RZ-
DQPSK system was deployed in 2007 in the trunk line between Tokyo and Osaka in
Japan. As shown in Fig. 1.14 [19], by comparing 0.25 b/s/Hz of single-polarization
OOK at 10 Gb/s with the frequency interval of 50 GHz, the spectral efficiency increases
drastically up to 6 b/s/Hz on adopting a multi-level modulation format. In addition, it has
become common practice to utilize polarization division multiplexing (PDM) to double
the transmission capacity. The 100 Gb/s transmission system which will be deployed
in 2013 in Japan uses the PDM QPSK modulation format. The quest for a higher bit
rate, such as 400 Gb/s per wavelength, is already underway, in which multi-level higher

12 Introduction
Figure 1.14 Spectral efficiency of commercial systems versus year [19]. C
Reprinted by
permission of IEEE.
than QPSK, for example, 16-QAM and 64-QAM, will be adopted. It should be remem-
bered that the price to be paid is a higher signal-to-noise ratio and shorter transmission
distance. The key enabler for detecting the phase information of an optical carrier is a
digital coherent transmission technique. This is because coherent receivers are capable of
measuring phase and polarization as well as amplitude. Coherent optical communication
attracted much attention in the mid-1980s [20, 21] because of its better receiver sensi-
tivity compared with direct detection, leading to extension of the transmission reach in a
long-haul transmission system. With the emergence of optical fiber amplifiers, however,
interest in coherent optical communication decreased because the EDFA pre-amplifier
was a much easier way to increase the receiver sensitivity than coherent detection.
The digital coherent transmission differs from its predecessor in that it is intended
to equalize dynamically rather than statically the deterioration of multi-level modulated
optical signals caused by chromatic and polarization dispersion with the aid of pow-
erful digital signal processing (DSP). This is a result of the rapid progress in silicon
complementary metal oxide semiconductor (CMOS) LSI technology, underpinned by
Moore’s law. In such a way the limitation to the transmission distance has been over-
come, although it is not perfect. With the power of DSP, another problem of the frequency
carrier offset between the light sources at the transmitter and the local oscillator has been
solved. This tolerates a rigid requirement for the phase stability of the light sources of
heterodyne and homodyne detection, which was one of the stumbling blocks in the pre-
vious coherent detection. At first, DSP at the symbol rate resorted to offline processing.
Very recently, however, a milestone of 127 Gb/s PDM-QPSK Ethernet over OTN has
demonstrated a chromatic dispersion compensation of 40,000 ps/nm by using real-time

Figure 1.15 100 Gb/s digital coherent signal processor LSI: configuration and DSP module [22].
C
Reprinted by permission of the Optical Society of America.
DSP at the receiver [22]. The receiver configuration along with a photograph of the DSP
package is shown in Fig. 1.15. The DSP consists of a training sequence addition/removal
framer, analog-to-digital converter, equalizers, framer synchronizer, and forward error
correction (FEC) en/decoder.
On increasing the transmission capacity per fiber, the total input power goes up. This
raises two issues: one is non-linear effects of optical fibers, and the other is physi-
cal damage to optical fibers. C. E. Shannon forecast [23] that the capacity of a linear
channel with additive noise would grow indefinitely with increasing signal power. How-
ever, this is not the case with non-linear channels of optical fiber transmission systems.
The most predominant non-linear effect arises from the intensity dependent refractive
index (Kerr effect) and results in a number of phenomena such as self-phase modu-
lation, cross-phase modulation and inter-channel and intra-channel four-wave mixing.
The theoretical analysis in Fig. 1.16 shows that the capacity of a non-linear channel
does not grow indefinitely with increasing signal power, but has a maximal value [24].
This is a fundamental feature which distinguishes non-linear communication channels
from linear communication channels. According to the theory [25], if the non-linear
coefficient γ could be reduced by a factor of 1000 from the value of a conventional
single-mode fiber, which is nearly achievable in an ideal hollow-core fiber [26], the
spectral efficient would increase by 80%. On the other hand, the reduction in fiber loss,
even by a factor of one third conjectured in hollow-core fibers, has a very limited effect
on the spectral efficiency.
In Fig. 1.17 the total input power in a fiber is plotted as a function of the product of
the transmission capacity and the distance for various transmission experiments [11].
It is predicted that to realize a 1 Pb/s transmission system, a few watts of total input
signal power will be required, and this exceeds the threshold power of physical damage
to conventional optical fibers. One of the predominant types of damage is the so-called

14 Introduction
Figure 1.16 Spectral efficiency versus signal power spectral density [24]. C
Reprinted by
permission of Nature.
Figure 1.17 Total input power versus product of the transmission capacity and the distance [11].
C
Reprinted by permission of NTT.
“fiber fuse.” The laser light propagating in the fiber is strongly absorbed by the heated
part when a fiber is heated locally to a temperature of about 1000 °C, and this heating
induces a breakdown of the transparency of the fiber. The threshold of total input power
for fiber fuse is 1.21.4 W. More details of fiber fuse will be described in Section 10.4.2.

Figure 1.18 Optical networks: WAN, MAN, and Access/LAN.
1.4 Optical networks
A network consists of nodes and point-to-point links in between the nodes. A switch
which connects a link with another link is located at a node. The connection between the
links may be either one-to-one or one-to-many, that is, so-called multipoint connection.
A nationwide telecom network is broken up into wide area networks (WANs) or long-
haul networks, metropolitan area networks (MANs), and local area networks as shown in
Fig. 1.18. A WAN or long-haul network interconnects cities, extending over thousands of
kilometers across a continent, while a MAN is an interoffice network of city size, typically
a few tens of kilometers, in which central offices (COs) of the carrier interconnect. The
access network extends from a central office to LANs in business districts, campuses
and residential zones. In the access network, optical fibers or metal cables are laid from
each telephone office to customers’ homes in an area of typically ten or a few tens of
kilometers. WANs and MANs are owned by telecom carriers, and LANs are privately
owned networks. From a topological viewpoint, a WAN is logically a mesh network
whether or not the nodes are physically connected with a pair of optical fiber cables.
There will be direct connections between the central offices, and there may be a logical
connection as denoted by a dotted line in the figure. In reality the long-haul network of
NTT consists of ring networks, interconnected through a gateway node.
The telecommunication network has been evolving from an opaque network to a
transparent network by incorporating technological innovations. An opaque network is at

16 Introduction
Figure 1.19 State-of-the-art optical network in Japan. Updated after [10].
an intermediate stage, in which metal cables in the point-to-point links are replaced with
optical fiber cables before the optical switches replace electrical switches at the nodes.
Therefore, the optical signal has to undergo optical-to-electrical (OE) and electrical-to-
optical (EO) conversions each time it passes through the switch at the node. Currently,
the public network of NTT in Japan, shown in Fig. 1.19 [10], is translucent, which means
that part of the network has become transparent, and the rest of it remains opaque. In the
metro ring network in large cities, a small-scale optical switch, a reconfigurable add/drop
multiplexer (ROADM), has been deployed at nodes.
A typical architecture of a four-degree wavelength-selective switch (WSS) based
ROADM is shown in Fig. 1.20 [27]. At the input port of the ROADM, the optical power
splitter creates multiple copies of input WDM channels, and one copy is sent to each
output port. At the output port, all copies of the WDM channels from each of the other
input ports are injected into different WSS ports. The WSS possesses a single common
port and multi-wavelength ports. The output of the WSS common port is amplified and
launched onto the outbound transmission fiber. A copy of all WDM channels is directed
to an arrayed waveguide grating (AWG) filter which demultiplexes individual channels
for local optical link termination (drop). Similarly, another AWG filter multiplexes the
input from a series of wavelength-specific add ports onto a single fiber connected to one
of the ports of the WSS. By introducing optical switches into the network, a dynamic
configuration of the network is enabled, and thus connections can be dynamically set up
and torn down on demand. For example, traffic engineering can be performed in such a
way that more bandwidth or wavelength can be assigned where the traffic increases, and
less wavelength can be assigned as the traffic volume becomes smaller. This will be the

Figure 1.20 Architecture of colorless, directionless, and contentionless ROADM [27]. C

case during the daytime and during the night in the business districts and residential areas.
However, the ROADM has limitations in its functionality because a fixed wavelength is
assigned to specific ports, a fixed direction is assigned to the wavelength multiplexer and
demultiplexer, and add/drop is partitioned to avoid wavelength contention. Flexibility in
ROADM switching capability will be enhanced by adding the functionalities colorless,
directionless, and contentionless (CDC) to the WSS. A downside of the CDC ROADM
will be its high cost because it requires a large number of transmitters and receivers.
By scaling up the ROADM an optical cross-connect (OXC) switch having a large port
count can be configured. The OXC switch can switch a number of a optical signals from
the input ports to output ports without OE–EO conversion. This switch is expected to be
deployed at the nodes in long-haul networks in the near future. The evolution of opaque
to transparent will create optical networks in a true sense. The benefits gained from an
optical network are summed up as follows:

18 Introduction
Figure 1.21 Three topologies of networks: (a) centralized, (b) decentralized, and (c) distributed
[28]. C
IEEE by permission.
r minimum latency,
r larger bandwidth,
r reduction of power consumption.
Packet switching is a basis of the Internet. The concept of packet switching was invented
by Paul Baran in the mid-1960s. The motivation for this concept was to enhance
the survivability of military-owned networks against attack during the cold war era.
Figure 1.21 shows original drawings of three different networks, centralized, decentral-
ized, and distributed networks [28]. The centralized network has all its nodes connected
to a central switching node to allow simple switching, giving it a single point of high
vulnerability, while the decentralized network comprises small centralized clusters. The
distributed network is a network without any hierarchical structure. There is no single
point which is vulnerable to paralysis, unlike the centralized topology. The network
has to respond quickly to changes caused by damage and has the capability to deflect
traffic autonomously from the point of damage and route to other surviving nodes. To
enable this, the idea is to send digital data by segmenting the message into packets
and allowing the packets to traverse through nodes hop by hop. For example, if half
the network is instantly destroyed, the remainder of the network reorganizes itself and
routes traffic effectively. The routing protocol travels along with packets by going to and
from addresses so that according to the address the node can forward the packet to the
next neighboring node. The concept of packet switching in a distributed network helped
built the ARPANET, the origin of Internet Protocol (IP). The structure of a packet of
the current IP version 4 (IPv4) is shown in Fig. 1.22. The header consists of 32-bit

Header Data (512~65,472-Byte)
Version IHL Type of service
Identification Frags Fragment offset
Time to live Protocol Header checksum
Source address
Destination address
Option Padding
Total length
Figure 1.22 Structure of IPv4 header.
long IP addresses of the source and destination. An 8-bit time to live (TTL) field helps
prevent packets from circulating in the Internet. Each router decrements the TTL count
by one as the packet traverses the router, and the packet is no longer forwarded and is
discarded when the time to live field hits zero. It is noteworthy that the next version of
IP, IPv6, has 128-bit long addresses, which was developed to deal with the anticipated
exhaustion of addresses of IPv4. It is difficult to imagine the total number of addresses,
2128
, approximately 340 undecillion (=1036
). A good way to visualize this value is to
imagine the size of address space that one would fill with a corresponding number of
1 mm3
grains of sand. This would be equivalent to 300 million planets Earth.
It is useful to look at the fundamental differences between packet switching and
circuit switching as summarized in Fig. 1.23 [29]. Circuit switching, which the plain
old telephone service is based upon, guarantees quality of service (QoS). This means
that unless the circuit is not busy, the circuit is established, and the message can reach
the receiver without loss of data bits. However, if the circuit is busy, call loss occurs,
requiring a re-dial. In packet switching, by contrast, the message is stored in a buffer
at each node and sent out if the bandwidth is available for the next hop, and hence
queuing delay occurs. If the buffer is full upon the arrival of the packet, the packet
will be discarded, and packet loss occurs. As a consequence, the level of service is not
guaranteed QoS but it is a best effort service. The cost is crucial. Packet switching can
offer a less expensive service than circuit switching because of its better bandwidth
utilization.

20 Introduction
Figure 1.23 Circuit switching versus packet switching [29]. C
Reprinted by courtesy of
H. Miyahara.
An example of the end-to-end connection is illustrated in Fig. 1.18. The data signal
bearing a customer’s message generated at the optical network unit (ONU) in the source
access network goes into the MAN, traverses over the WAN to the other MAN, and
reaches the destination access network. Suppose that the data signal is carried in Ethernet
frames and transmitted over GE-PON. The Ethernet frames are aggregated in a central
office. At the central office the traffic from ONUs is further aggregated and encapsulated
into optical transport units (OTUs) at 10 Gb/s or even higher, say 100 Gb/s, and sent out
over the WAN to the destination MAN, followed by delivery to the destination access
network. The OTU is a frame defined in optical transport network (OTN) architecture.
The OTN provides cost-effective transparent transport over WDM networks for a variety
of client signals such as the Ethernet and synchronous optical network (SONET), which
is standardized by ITU-T. The Ethernet frame can only be transmitted over 40 km or
less, and the OTN enables long-haul transmission by adding necessary functions such
as forward error correction (FEC) and encapsulating an Ethernet frame in the OTN as
shown in Fig. 1.24. As summarized in Table 1.1, four data rates are available which are
all compatible with the data rates of existing Ethernet frames.
An emerging transmission technique with an elastic bandwidth or bit rate will have a
significant impact on WDM networks. As shown in Fig. 1.25, an optical path is no longer
of a fixed bandwidth but can be flexible on demand. For example, for a longer reach
the bandwidth of the optical path has to be decreased, and for a shorter reach a higher
bandwidth optical path can be established. This flexibility in optical path provisioning
will enhance efficiencies in spectrum utilization, protection, and power consumption.
The conventional paradigm of WDM will shift to a new “flexible grid network.” Key
optical components include a bandwidth-tuneable WSS and bit rate-adaptive transmitter

Table 1.1 OTN/SONET/Ethernet transmission rates
Data rate (Gb/s) OTN SONET OC Ethernet
2.488 48
2.67 1
9.689 192
10.7 2 10GbE
43.0 3 40GbE
112.0 4 100GbE
OTN optical-channel transport unit; SONET synchronous
optical network; OC optical carrier level.
Figure 1.24 Frame structures of optical channel transport (OUT).
and receiver. The standardization of the flexible grid in ITU-T G694.1 was completed
in 2012. As shown in Fig. 1.26, it recommends a slot width with slot width granularity
of 12.5 GHz along with a nominal central frequency granularity of 6.26 GHz [30]. This
flexible grid will allow a mixed bit rate transmission system to allocate frequency slots
with different widths, leading to better exploitation of the spectrum.
Finally, to cope with the problem of global warming, one has to be conscious of
the energy consumption of information and communication technology (ICT). The
breakdown of power consumption of ICT forecast in 2020 in Japan is shown in Fig. 1.27
[31]. Note that this forecast is based upon the assumption that no countermeasure of
power saving is taken. The energy consumption of ICT is only 6% of the total energy
consumption in 2012 in Japan, but it is forecast to reach 10% of the total 125.6 billion
kWh in 2020 with the CAGR, the annual growth rate of 6%. In the breakdown, the LAN
switches and routers along with their cooling and ventilation consume 43%, while the

22 Introduction
Figure 1.25 Evolution of the optical path from static bandwidth to elastic bandwidth.
Figure 1.26 Flexible grid [30]. C
Reprinted by permission of ITU-T.
wired and wireless communications consume less power, 14%. This is a warning that one
should pay serious attention to reducing the power consumption of ICT, particularly of
L2/L3 switches, widely deployed in data centers, and Internet exchanges to residential
areas. Therefore, it may be the case in the future that cutting-edge highly functional
transmission and network equipment and components will not be acceptable to the
market if they are not energy efficient.

Figure 1.27 Power consumption of ICT in 2020 [31]. C
Reprinted by permission of the Ministry
of Internal Affairs and Communications in Japan.
1.5 Access networks
“Last mile” is a generic term for any final leg of broadband connectivity from a telecom-
munications provider to the subscriber in an access network. It is sometimes referred
to as “first mile” because it is the first mile from the subscriber to the service provider.
Access networks fall into three categories: wireless, copper, and fiber. Cost is the first
priority for service providers. The cost of deploying the access system has to be min-
imized, while maximizing revenue from the service offerings. In order to reduce the
cost, the digital subscriber line (DSL) uses installed twisted pairs of copper cable for
telephony. Voice for telephony occupies up to 4 kHz of the bandwidth of copper cables,
and DSL uses the higher frequency band. As seen in Fig. 1.28, the line rates of VDSL
and ADSL decrease rapidly due to attenuation as the distance increases. DSL is capable
of 30 Mb/s for a distance of 1 km, but it can only provide less than 10 Mb/s for a
reach of 3 km. DSL uses a point-to-point architecture which is distinct from the wireless
network which uses point-to-multipoint (P2MP) architecture, and the whole bandwidth
is dedicated to each subscriber. Although DSL has a slight edge over PON in terms of
cost, the raw bandwidth capability of PON overwhelms that of DSL. This is why PON
has penetrated widely, replacing deployed DSL.

24 Introduction
Figure 1.28 Bandwidth versus distance of digital subscriber line (DSL).
Wireless has the lowest deployment cost because it has the lowest outside plant costs.
WiFi and WiMAX1
are widely deployed among the wireless family. WiFi has a range
of only 100 m and a bit rate of 10–50 Mb/s. WiMAX is designed for fixed and mobile
access networks, and its data rate is 70 Mb/s only if the distance is shorter than 5 km.
They use point-to-multipoint (P2MP) architecture, and hence the bandwidth has to be
shared with multiple subscribers. Therefore, wireless access lacks sufficient bandwidth
to support high bandwidth video applications such as IPTV broadcasting.
The last but not least option to be considered for access networks is optical fibers.
Fiber-to-the-Home (FTTH) adopts optical devices and components developed for long-
haul optical fiber transmission systems and high-volume products of LAN technology
such as the Ethernet. FTTx is the access network which connects between the central
office (CO) and subscribers with optical fibers. FTTx (Fiber-to-the-x) is the deployment
of fiber cables to a specific location with regard to the customer premises. The “x” is used
to represent the specific application of the service. In Fig. 1.29, x represents a node, curb
or cabinet, building or basement, cell, or home. The difference between various “x” is in
the degree of fiber penetration. In Fiber-to-the-Node (FTTN) the fiber is terminated in a
street cabinet up to several kilometers away from the subscriber premises, with the final
connection being copper. In Fiber-to-the-Curb/Cabinet (FTTC) the fiber is terminated
in a street cabinet which is closer to the subscriber premises, typically within 300 m. In
Fiber-to-the-Building/Fiber-to-the-Basement (FTTB) and Fiber-to-the-Office (FTTO),
the fiber reaches the building, for example the basement, with a final copper connection
to the individual space. Obviously, the deeper the penetration of fiber to the subscriber
premises becomes, the higher the bit rate that can be offered. FTTB can offer the highest
1 WiFi and WiMAX are standards of IEEE802.11 and IEEE802.16, respectively.

Figure 1.29 Architectures of various FTTx.
bit rate since the remaining segments use standard Ethernet or coaxial cable. The other
FTTxs generally use VDSL for the final leg.
In addition, the next-generation PON architecture will include fiber-to-the-cell (FTT-
Cell) backhaul applications via a cell-site backhaul unit (CBU) to the cellular base
stations. Network convergence offers the prospect of optimizing the total cost of owner-
ship (TCO) for network operators by eliminating heterogeneous and manifold network
technology solutions in the access and aggregation domains. In this context, fixed access
backhauling and mobile backhauling must be considered. Long Term Evolution (LTE)
and LTE-Advanced (LTE-A) are the relevant mobile network technologies for which
NG-PON2 systems must provide backhauling solutions:
CBU: Cell-site backhaul unit
SFU: Single Family Unit
SBU: Single Business Unit
MTU: Multi Tenant Unit
MDU: Multi Dwelling Unit.
The passive optical network (PON) is the most important class of fiber access system.
The typical outside plant shown in Fig. 1.30 consists of equipment and components
located between the OLT (optical line terminal) in the CO, also referred to as the
head-end, and the optical network units (ONUs) in the customer premises. Photographs
of overviews of OLTs and ONUs are also shown in the inset. At the CO the public-
switched telephone network (PSTN) and Internet services are interfaced with the optical
distribution network (ODN) via the OLT. The gear and components include both optical

26 Introduction
Figure 1.30 Outside plant of FTTH, courtesy of H. Shinohara, NTT and S. Kinoshita, Fujitsu.
and non-optical components of the network. The optical components make up the
optical distribution network (ODN) and include splices, connectors, splitters, optical
fiber cables, patch cords and possibly drop terminals with drop cables. The non-optical
components include pedestals, cabinets, patch panels, splice closures and miscellaneous
hardware. The optical fiber cables consist of the feeder cable from the OLT to the first
splitter, distribution cable linking the splitter to the drop terminal near the subscribers,
and the dedicated drop cables (30 m) connecting to the individual ONUs. Details of the
optical components are described in Chapter 5. Installation of outside plant equipment
in an FTTx network can be carried out in many ways, and each installation may be
different, depending on factors such as the distance from the CO, residential density
and distribution urbanism etc. Optical fiber cables can be installed using either aerial
or underground installation techniques. The placement of splitters and other passive
components and cabinets used depends on geographical factors and on the PON topology.
In Fig. 1.31 cross-sectional views of conventional (on the left) and ultra-high-density
optical fiber cables (on the right) for the feeder cable section and the distribution cable
section are shown. Both cables have 200 optical fibers [32]. Compared with the con-
ventional cable, the newly developed cable, which will be deployed in commercial PON
systems in 2012, is significantly thinner and lighter. The inset of Fig. 1.31 shows 420
0.25 mm diameter primary-coated optical fibers aligned with an adhesive UV curable
resin. This structure enables the fiber ribbon to be rolled up easily and accommodated
very tightly in a cable. The ribbon can be spliced by mass fusion splicing machines
or connected mechanically using a connector. Mechanical splices are the least expen-
sive but have higher insertion loss and back-reflections than fusion splices. The fusion

Figure 1.31 Structure of optical fiber cable for the feeder cable [32]. C
Reprinted by permission
of Elsevier.
splice has very low loss (0.1 dB) and almost no back-reflection but typically requires
expensive and extensive fusion-splicing equipment and a well-trained technician; see
the fusion splice machine shown in Fig. 1.12. The number of splices depends on the
cable section lengths used, a typical section length being 26 km.
There are two types of connections in the FTTH architecture: point-to-point and
P2MP. Point-to-point architecture uses a dedicated fiber from the CO to each subscriber,
referred to as a point-to-point network, while in the P2MP architecture a single fiber
from the CO is shared with a number of subscribers. The PON has two main advantages.
r There is no requirement to install and maintain active components. Hence, operators
can significantly reduce the power requirements for the outside plant. Furthermore,
PON provides a more reliable access network solution due to the increased reliability
of the optical fiber and passive splitters.
r Owing to P2MP architecture, the cost of deploying an optical access infrastructure is
lower compared for example with point-to-point topologies because the cost of fiber
installation between the CO and subscribers is shared among many subscribers. This
contrasts with point-to-point access solutions.

28 Introduction
Figure 1.32 Passive optical network: (a) single star topology, and (b) double star topology.
Figure 1.33 Active double star topology.
The architecture of a PON is classified into two categories: single star and double star,
shown in Fig. 1.32(a) and (b), respectively. The single star architecture is of point-to-point
topology, while the double star architecture is in the form of P2MP. In the double star
architecture there is a splitter between an OLT and a number of subscribers. If the
splitter is a passive optical device, it is classified in the passive category. A passive
optical splitter, a so-called star coupler, works in such a way that the power of the
downstream signal is simply split and delivered to the subscribers, and the upstream
signals from subscribers are combined and transmitted to the OLT. See Chapter 4 for
more details of the star coupler.
The physical topology of an active network resembles a PON, in which the optical
splitter is replaced with powered electronics such as an Ethernet switch, electronic-to-
optical (EO) and optical-to-electronic (OE) converters, and an amplifier (Fig. 1.33). The
logical topology is not P2MP but point-to-point because each subscriber is provided with
a dedicated link of full bandwidth. Owing to the electronics, the distance limitation is

1.6 Local area networks 29
80 km, regardless of the number of subscribers. However, it requires a large investment
in the outside plant. Switches have to be installed in secured cabinets between the CO
and the subscribers.
Scaling of PON systems in terms of the number of users, geographic coverage, and
the transmission capacity has a significant impact on holding back both CAPEX and
OPEX. Long-reach PON would be a cost-effective solution by consolidating several COs
into a single CO. The transmission distance between the OLT and ONUs of 10G-EPON
systems needs to be extended from the traditional 20 km range (60 km in the case of
ITU-T G.987.4 extended reach XG-PON). An extension to over 100 km is desirable
because it would allow several telephone central offices to be consolidated and would
widen the coverage of PON. By extending geographic coverage, long-reach PON can
combine optical access and metro networks into an integrated system. Without the long
reach capability, the PON system cannot be deployed widely in the near future. The split
ratio is another issue for the system economics. To attain the maximum split ratio based
on the given power budget, the current 10G-EPON and XG-PON are standardized at
a maximum 32 and 64-way split. Increasing the split ratio beyond 1:64 (e.g., 1:128 to
1:256) is attractive, especially for the service-independent introduction scenario, so
that it improves the overall economics of 10G-EPON and XG-PON passively. This is
summarized in Table 2.1.
1.6 Local area networks
The Ethernet is a predominantly LAN technology. It was originally developed by
R. Metcalfe2
at the Palo Alto Research Center, XEROX in 1973 for computer network-
ing, and was introduced commercially by 3Com in 1980. The working group IEEE803.3
standardized the first 10BASE5 Ethernet at 10 Mb/s in 1982. This used coaxial cable as
a shared medium. Since the use of a single cable also means that the bandwidth is shared,
the network traffic can be very slow when many terminals are active simultaneously.
Hence, the coaxial cables were soon replaced by twisted pairs of copper cables and
optical fiber links to meet market demand for higher data rates. The data rate has been
increased by a factor of ten from the original 10 Mb/s to 100 Mb/s and 1 Gb/s in 1998,
followed by 10 Gb/s in 2003. Note that the Ethernet at x-Gb/s is traditionally referred
to as x-GbE. In 2010, 100GbE along with 40GbE were standardized [33]. This rapid
upgrading of the data rate is motivated by the ever increasing bit rate of the backbone
network. It is interesting that the line rate follows the trend of CPU speed doubling every
twenty-four months but this is only natural because the Ethernet provides the computer
interface, the network interface card (NIC), which connects computer terminals to the
LAN.
100GbE will enable the realization of end-to-end connections between LANs at 100
Gb/s by directly bridging over the WAN without any bit rate conversion. As shown in
2 A well-known assertion by Metcalf states that “The usefulness, or utility, of a network equals the square of
the number of subscribers.”

30 Introduction
Fig. 1.24, a client signal of the Ethernet frame is encapsulated in the OTN frame and
transported over the WAN. Systems communicating over the Ethernet segment a stream
of data into individual packets called frames. A unique identifier, a 48 bit MAC address,
is assigned to each NIC so that any information sent by one terminal is received by all,
even if that information is intended for just one destination. Each frame contains source
and destination addresses and error-checking data so that damaged data can be detected
and re-transmitted. Carrier sense multiple access with collision detection (CSMA/CD)
protocol is used for the media access control (MAC) protocol, which enables a number
of computer terminals in the LAN to share the medium without collision. Since all
communications happen on the same wire, collision occurs in a way that a message
overlaps in time with the other messages using the shared medium. Each terminal
eventually learns of the collision by CSMA/CD protocol and tries again later.
Problems
1.1 What makes the broadband service distinct from the plain old telephone service?
1.2 What are the most important inventions in optical fiber communications?
1.3 By comparing TDM and WDM, discuss their merits and demerits from the view-
points of the line rate, capability of compound line rate, and cost of repeaters.
1.4 What are the benefits of replacing an electrical switch with an optical switch?
1.5 By comparing FTTH with DSL, discuss the merits of both systems.

Part I

2 Optical multiple access systems
2.1 Passive optical network
2.1.1 Technology roadmap
Various PON systems are currently in commercial operation. As the number of sub-
scribers is growing rapidly throughout the world, as described in Section 1.1, and as
there is a perennial demand for higher bit rates, the PON system is continuously evolv-
ing and is expected to experience further evolution in the future. Network operators are
motivated to leverage the next-generation (NG) networks to deliver high bandwidth to
mobile cell sites for 3G/4G backhaul as well. Two types of gigabit-class PON systems
have been standardized: the gigabit Ethernet passive optical network (1G-EPON) by the
Institute of Electrical and Electronics Engineers (IEEE) and the gigabit-capable passive
optical network (G-PON) by the International Telecommunication Union, telecommuni-
cation standardization sector (ITU-T). The gigabit-class PON is currently under deploy-
ment worldwide. Hereafter, 1G-EPON is abbreviated as EPON. Prior to the gigabit-class
PON, the broadband passive optical network (BPON) was rolled out. Having had major
investment by operators in deploying G-PON and EPON, NG-PON must be able to
protect the investment of the legacy PONs by ensuring seamless subscriber migration
from existing PON architectures such as gigabit-class PON to NG-PON. G-PON and
EPON will be detailed in Section 2.1.2. NG-PON is required to fully support various
services for residential subscribers, business customers, and mobile backhaul through
its high quality of service and high bit rate capability.
A technology roadmap toward NG-PON is shown in Fig. 2.1 [1]. There are two
categories: NG-PON1 and NG-PON2. NG-PON1 aims at evolutionary growth, and
it can support “brown field” deployment, where co-existence with G-PON/EPON on
the same optical distribution network (ODN) is a must. ODN refers to the fiber plant
and the splitter between the OLT and ONUs. The co-existence with legacy systems
enables seamless upgrade of individual subscribers to NG-PON on a live ODN without
disrupting the services of other subscribers. On the other hand, NG-PON2 supports
“green field” deployment, aiming at revolutionary growth, and it may be disruptive
with no requirement in terms of co-existence with G-PON/EPON on the same ODN.
XG-PON in NG-PON1 represents a PON system with 10 Gb/s line rate, at least in the
downlink direction (X taken as the roman sign for 10). The uplink line rate candidates

34 Optical multiple access systems
Figure 2.1 Technology roadmap toward NG-PON [1]. C
Reprinted by permission of IEEE and
modified.
include 2.5 and 10 Gb/s. On the other hand, NG-PON2 is supposed to be adopted after
NG-PON1. NG-PON2 is not constrained by co-existence requirements, and it can be
preferably deployed in a “green-field” because the deployment of optical fibers should
become cheaper than copper in the future. Many technical candidates are involved such
as 100G/400G TDM, dense WDM (DWDM), OCDMA, and OFDMA. It is too early to
pick one of these as the best candidate because extensive research and development on
components is needed.1
Among the candidate technologies for NG-PON2, OCDMA provides another dimen-
sion for multiple access, other than TDMA using time slots and WDMA using wave-
length. The unique and the most attractive property of OCDMA is its asynchronous
nature. OCDMA can support a fully asynchronous transmission, which allows all the
users to access on demand without contention. In contrast, TDMA requires a tight
control on synchronization, and WDMA needs a tight control on wavelength. As the
optical encoding and decoding are performed in the optical domain, the low latency of
data transmission is guaranteed, and neither the transmitter nor the receiver requires any
complex electrical equipment. OCDMA can provide soft capacity on demand, in that
users can be added to the network on demand by assigning new optical codes. Another
advantage of OCDMA is the inherent nature of data confidentiality, because messages
are encoded at the transmitter and can be recovered only by the authorized user, who
knows the optical code.
1 At the time of writing the objective of NG-PON2 has been shifted from a revolutionary technology to an
evolutionary technology such as WDM-TDMA-PON, and legacy co-existence capabilities with G-PON or
XG-PON have been emphasized [2]. The standardization of NG-PON2 will be completed by 2015 or even
earlier. A revolutionary approach in a true sense is likely to appear on the scene as the post NG-PON2,
NG-PON3.

Another Random Document on
Scribd Without Any Related Topics

The game of Authors, especially when created by the persons who
wish to play it, is very interesting. The game can be bought and is a
very common one, as perhaps every one knows, but it can be
rendered uncommon by the preparation of the cards among the
members of the family. There are sixty-four cards to be prepared,
each bearing the name of a favourite author and any three of his
works. The entire set is numbered from one to sixty-four. Any four
cards containing the name and works of the same author form a
book.
Or the names of kings and queens and the learned men of their
reigns may be used, instead of authors; it is a very good way to
study history. The popes can be utilized, with their attendant great
men, and after playing the game for a season one has no difficulty in
fixing the environment of the history of an epoch.
As the numbers affixed to the cards may be purely arbitrary, the
count at the end will fluctuate with great impartiality. The Dickens
cards may count but one, while Tupper will be named sixteen.
Carlyle will only count two, while Artemas Ward will be sixty. King
Henry VIII., who set no small store by himself, may be No. I in the
kingly game, while Edward IV. will be allowed a higher numeral than
he was allotted in life.
Now we come to a game which interests old and young. None are so
apathetic but they relish a peep behind the dark curtain. The apple-
paring in the fire, the roasted chestnut and the raisin, the fire-back
and the stars, have been interrogated since time began. The pack of
cards, the teacup, the dream-book, the board with mystic numbers,
the Bible and key, have been consulted from time immemorial. The
makers of games have given in their statistics, and they declare
there are no games so popular as those which foretell the future.
Now this tampering with gruesome things which may lead to bad
dreams is not recommended, but so long as it is done for fun and an
evening's amusement it is not at all dangerous. The riches which are
hidden in a pack of fortune-telling cards are very comforting while

they last. They are endless, they are not taxed, they have few really
trying responsibilities attached, they bring no beggars. They buy all
we want, they are gained without headache or backache, they are
inherited without stain, and lost without regret. Of what other
fortune can we say so much?
Who is not glad to find a four-leaved clover, to see the moon over his
right shoulder, to have a black cat come to the house? She is sure to
bring good fortune!
The French have, however, tabularized fortune-telling for us. Their
peculiar ability in arranging ceremonials and fêtes, and their
undoubted genius for tactics and strategy, show that they might be
able to foresee events. Their ingenuity, in all technical contrivances,
is an additional testimony in the right direction, and we are not
surprised that they have here, as is their wont, given us the practical
help which we need in fortune-telling.
Mademoiselle Lenormand, the sorceress who foretold Napoleon's
greatness and to many of the great people of France their downfall
and misfortunes, has left us thirty-six cards in which we can read the
decrees of fate. Lenormand was a clever sybil. She knew how to mix
things, and throw in the inevitable bad and the possible good so as
at least to amuse those who consulted her.
In this game, which can be bought at any bookstore, the cavalier, for
instance, is a messenger of good fortune, the clover leaf a harbinger
of good news, but if surrounded by clouds it indicates great pain, but
if No. 2 lies near No. 26 or 28 the pain will be of short duration, and
so on.
Thus Mlle. Lenormand tells fortunes still, although she has gone to
the land of certainty, and has herself found out whether her symbols
and emblems and her combinations really did draw aside the curtain
of the future with invisible strings. Amateur sybils playing this game
can be sure that they add to the art of entertaining.

The cup of tea, and the mysterious wanderings of the grounds
around the cup, is used for divination by the old crone in an English
farmhouse, while the Spanish gypsy uses chocolate grounds for the
same purpose. That most interesting of tragic sybils, Norna of the
Fitful Head, used molten lead.
Cards from the earliest antiquity have been used to tell fortunes.
Fortuna, courted by all nations, was in Greek Tyche, or the goddess
of chance. She differed from Destiny, or Fate, in so far as that she
worked without law, giving or taking at her own good pleasure. Her
symbols were those of mutability, a ball, a wheel, a pair of wings, a
rudder. The Romans affirmed that when she entered their city she
threw off her wings and shoes, determined to live with them forever.
She seems to have thought better of it, however. She was the sister
of the Parcae, or Fates, those three who spin the thread of life,
measure it, and cut it off. The power to tell fortunes by the hand is
easily learned from Desbarolles' book, is a very popular
accomplishment, and never fails to amuse the company and interest
the individual.
It must not be made, however, of too much importance. It never
amuses people to be warned that they may expect an early and
violent death.
Then comes Merelles, or Blind Men's Morris, which can be played on
a board or on the ground, but which now finds itself reduced to a
parlour game. This takes two players. American Bagatelle can be
played alone or with an antagonist. Chinese puzzles, which are
infinitely amusing, and all the great family of the Sphinx, known as
puzzles, are of infinite service to the retired, the invalid, and weary
people for whom the active business of life is at an end.
We may describe one of these games as an example. It is called The
Blind Abbot and his Monks. It is played with counters. Arrange eight
external cells of a square so that there may be always nine in each
row, though the whole number may vary from eighteen to thirty-six.
A convent in which there were nine cells was occupied by a blind

abbot and twenty-four monks, the abbot lodging in the centre cell
and the monks in the side cells, three in each, giving a row of nine
persons on each side of the building. The abbot suspecting the
fidelity of his brethren often went out at night and counted them.
When he found nine in each row, the old man counted his beads,
said an Ave, and went to bed contented. The monks, taking
advantage of his failing sight, contrived to deceive him, so that four
could go out at night, yet have nine in a row. How did they do it?
The next night, emboldened by success, the monks returned with
four visitors, and then arranged them nine in a row. The next night
they brought in four more belated brethren, and again arranged
them nine in a row, and again four more. Finally, when the twelve
clandestine monks had departed, and six monks with them, the
remainder deceived the abbot again by presenting a row of nine. Try
it with the counters, and see how they so abused the privileges of
conventual seclusion!
Then try quibbles: How can I get the wine out of a bottle if I have
no corkscrew and must not break the glass or make a hole in it or
the cork?
The raconteur, or story-teller, is a potent force. Any one who can
memorize the stories of Grimm, or Hans Christian Anderson, or
Browning's Pied Piper, or Ouida's Dog of Flanders, or Dr. Holmes'
delightful Punch Bowl, and tell these in a natural sort of way is a
blessing. But this talent should never be abused. The man who, in
cold blood, fires off a long poetical quotation at a dinner, or makes a
speech when he is not asked, in defiance of the goose-flesh which is
creeping down his neighbours' backs, is a traitor to honour and
religion, and should be dragged to execution with his back to the
horses, like a Nihilist. It is only when these extempore talents can be
used without alarming people that they are useful or endurable.
Perhaps we might make our Christmas Holidays a little more gay.
There are old English and German customs beyond the mistletoe,
and the tree, and the rather faded legend of Santa Claus. There are

worlds of legendary lore. We might bring back the Leprechaun, the
little fairy-man in red, who if you catch him will make you happy
forever after, and who has such a strange relationship to humanity
that at birth and death the Leprechaun must be tended by a mortal.
To follow up the Banshee and the Brownie, to light the Yule log, to
invoke the Lord of Misrule, above all to bring back the waits or
singing-boys who come under the window with an old carol, and the
universal study of symbolism,—all this is useful at Christmastide,
when the art of entertaining is ennobled by the song Glory to God
in the highest, and on earth peace, good-will toward men.
The supper-table has unfortunately fallen into desuetude, probably
on account of our exceedingly late dinners. We sup out, we sup at a
ball, but rarely have that informal and delightful meal which once
wound up every evening.
Mrs. Elizabeth Montague, in her delightful letters, talks about the
Whisk, and the Quadrille parties, with a light supper, which amused
the ladies of her day. We still have the Whisk, but what has
become of lansquenet, quadrille basset, piquet, those pretty and
courtly games?
Whist! Who shall pretend to describe its attractions? What a relief to
the tired man of affairs, to the woman who has no longer any part in
the pageant of society! What pleasure in its regulating, shifting
fortunes. We have seen, in its parody on life, that holding the best
cards, even the highest ones, does not always give us the game. We
have noticed that with a poor hand, somebody wins fame, success,
and happiness. We have all felt the injustice of the long suit, which
has baffled our best endeavours. We play our own experience over
again, with its faithless kings and queens. The knave is apt to trip us
up, on the green cloth as on the street.
So long as cards do not lead to gambling, they are innocent enough.
The great passion for gambling is behind the game of boaston,
played appropriately for beans. We all like to accumulate, to believe

that we are fortune's favourite. What matter if it be only a few more
beans than one's neighbour?
That is a poorly furnished parlour which has not a chess table in one
corner, a whist table properly stocked, and a little solitaire table for
Grandma. Cribbage and backgammon boards, cards of every variety,
bezique counters and packs, and the red and white champions for
the hard-fought battle-field of chess, should be at hand.
Playing cards made their way through Arabia from India to Europe,
where they first arrived about the year 1370. They carried with them
the two rival arts, engraving and painting. They were the avants
couriers of engraving on wood and metal, and of the art of printing.
Cards, begun as the luxuries of kings and queens, became the
necessity of the gambler, the solace of all who like games. They have
been one of the worst curses and one of the greatest blessings of
poor human nature.
When failing health, or cross event,
Or dull monotony of days,
Has brought us into discontent
Which darkens round us like a haze—
then the arithmetical progression of a game has sometimes saved
the reason. They are a priceless boon to failing eyesight.
Piquet, a courtly game, was invented by Etienne Vignoles, called La
Hire, one of the most active soldiers of the reign of Charles VII. This
brave soldier was an accomplished cavalier, deeply imbued with a
reverence for the manners and customs of chivalry. Cards continued
from his day to follow the whim of the court, and to assume the
character of the period, through the regency of Marie de Medicis, the
time of Anne of Austria and of Louis XIV. The Germans were the first
people to make a pack of cards assume the form of a scholastic

treatise; the king, queen, knight, and knave tell of English customs,
manners, and nomenclature.
The highly intellectual game of Twenty Questions can be played by
three or four people or by a hundred. It is an unfailing delight by the
wood fire in the remote house in the wood, or by the open window
looking out on the lordly Hudson of a summer's night. It only needs
that one bright mind shall throw the ball, and half a dozen may
catch. Mr. Lowell once said there was no subject so erudite, no
quotation so little known, that it could not be reached in twenty
questions.
But we are not all as bright as James Russell Lowell. We can,
however, all ask questions and we can all guess; it is our Yankee
privilege. The game of Twenty Questions has led to the writing of
several books. The best way to begin is, however, to choose a
subject. Two persons should be in the secret. The questioner begins:
Is it animal, vegetable or mineral? Is it a manufactured object?
Ancient or modern? What is its shape, size and colour? What is its
use? Where is it now? The object of the answerer is of course to
baffle, to excite curiosity; it is a mental battledore and shuttlecock.
It is strange that the pretty game of croquet has gone out of favour.
It is still, however, to be seen on some handsome lawns. Twenty
years ago it inspired the following lines:—
CROQUET.

A painter must that poet be
And lay with brightest hues his palette
Who'd be the bard of Croquet'rie
And sing the joys of hoop and mallet.
Given a level lawn in June
And six or eight, enthusiastic,
Who never miss their hoops, or spoon,
And are on duffers most sarcastic;
Given the girl whom you adore—
And given, too, that she's your side on,
Given a game that's not soon o'er,
And ne'er a bore the lawn espied on;
Given a claret cup as cool
As simple Wenham Ice can make it,
Given a code whose every rule
Is so defined that none can break it;
Given a very fragrant weed—
Given she doesn't mind your smoking,
Given the players take no heed
And most discreetly keep from joking;
Given all these, and I proclaim,
Be fortune friendly or capricious,
Whether you win or lose the game,
You'll find that croquet is delicious.

ARCHERY.
The stranger he made no muckle ado,
But he bent a right good bow,
And the fattest of all the herds he slew
Forty good yards him fro:
'Well shot! well shot!' quoth Robin Hood.
Aim at the moon, if you ambitious are,
And failing that, you may bring down a star.
Fashion has brought us again this pretty and romantic pastime,
which has filled the early ballads with many a picturesque figure.
Now on many a lawn may be seen the target and the group in
Lincoln green. Indeed, it looks as if archery were to prove a very
formidable rival to lawn tennis.
The requirements of archery are these: First, a bow; secondly,
arrows; thirdly, a quiver, pouch, and belt; fourthly, a grease pot, an
arm-guard or brace, a shooting-glove, a target and a scoring-card.
The bow is the most important article in archery, and also the most
expensive. It is usually from five to six feet in length, made of a
simple piece of yew or of lance-wood and hickory glued together
back to back. The former is better for gentlemen, the latter for
ladies, as it is adapted for the short, sharp, pull of the feminine arm.
The wood is gradually tapered, and at each end is a tip of horn; the

one from the upper end being longer than the other or lower end.
The strength of bows is marked in pounds, varying from twenty-five
to forty pounds in strength for ladies, for gentlemen from fifty to
eighty pounds. One side of the bow is flat, called the back, the other,
called the belly, is rounded. Nearly in the middle, where the hand
should take hold, it is lapped round with velvet, and that part is
called the handle. In each of the tips of the horns is a notch for the
string, called the nock.
Bow strings are made of hemp or flax, the former being the better
material, for though at first they stretch more, yet they wear longer
and stand a harder pull, and are, as well, more elastic in the
shooting. In applying a fresh string to a bow, be careful in opening it
not to break the composition that is on it. Cut the tie, take hold of
the eye which will be found ready worked at one end, let the other
part hang down, and pass the eye over the upper end of the bow. If
for a lady, it may be held from two to two and a half inches below
the nock; if for a gentleman, half an inch lower, varying it according
to the length and strength of the bow. Then run your hand along the
side of the bow and string to the bottom nock. Turn it around that
and fix it by the noose, called the timber noose, taking care not to
untwist the string in making it. This noose is simply a turn back and
twist, without a knot. When strung a lady's bow will have the string
about five inches from the belly, and a gentleman's about half an
inch more. The part opposite the handle is bound round with waxed
silk in order to prevent its being frayed by the arrow. As soon as a
string becomes too soft and the fibres too straight, rub it with
beeswax and give it a few turns in the proper direction, so as to
shorten it, and twist its strands a little tighter. A spare string should
always be provided by the shooter.
Arrows are differently shaped by various makers; some being of
uniform thickness throughout, while others are protuberant in the
middle; some again are larger at the point than at the feather end.
They are generally made of white deal, with joints of iron or brass
riveted on, and have a piece of heavy wood spliced to the deal,

between it and the point, by which their flight is improved. At the
other end a piece of horn is inserted, in which is a notch for the
string. They are armed with three feathers glued on, one of which is
a different colour from the others, and is intended to mark the
proper position of the arrow when placed on the string, this one
always pointing from the bow. These feathers, properly applied, give
a rotary motion to the arrow, which causes its flight to be straight.
They are generally from the wing of the turkey or the goose. The
length and weight of the arrows vary, the latter in England being
marked in sterling silver coin and stamped in the arrow in plain
figures. It is usual to paint a crest or a monogram or distinguishing
rings on the arrow, just between the feathers by which they may be
known in shooting at the target.
The quiver is merely a tin case painted green, intended for the
security of the arrows when not in use. The pouch and belt are worn
round the waist, the latter containing those arrows which are
actually being shot. A pot to hold grease for touching the glove and
string, and a tassel to wipe the arrows are hung at the belt. The
grease is composed of beef suet and wax melted together. The arm
is protected from the blow of the string by the brace, a broad guard
of strong leather buckled on by two straps. A shooting-glove, also of
thin tubes of leather, is attached to the wrist by three flat pieces,
ending in a circular strap buckled around it. This glove prevents the
soreness of the fingers, which soon comes after using the bow
without it.
The target consists of a circular mat of straw, covered with canvas
painted in a series of circles. It is usually from three feet six inches
to four feet in diameter, the centre is gilt, and called the gold; the
ring about it is called the red, after which comes the inner white,
then the black, and finally the outer white. These targets are
mounted on triangular stands, from fifty to a hundred yards apart;
sixty being the usual shooting distance.
A scoring-card is provided with columns for each colour, which are
marked with a pin. The usual score for a gold hit, or the bull's-eye, is

9, the red 7, inner white 5, black 3, and outer white, 1.
To string the bow properly it should be taken by the handle in the
right hand. Place one end on the ground, resting in the hollow of the
right foot, keeping the flat side of the bow, called the back, toward
your person. The left foot should be advanced a little, and the right
placed so that the bow cannot slip sideways. Place the heel of the
left hand upon the upper limb of the bow, below the eye of the
string. Now while the fingers and thumb of the left hand slide the
eye towards the notch in the horn, and the heel pushes the limb
away from the body, the right hand pulls the handle toward the
person and thus resists the action of the left, by which the bow is
bent, and at the same time the string is slipped into the nock, as the
notch is termed. Take care to keep the three outer fingers free from
the string, for if the bow should slip from the hand, and the string
catch them, they will be severely pinched. In shooting in frosty
weather, warm the bow before the fire or by friction with a woollen
cloth. If the bow has been lying by for a long time, it should be well
rubbed with boiled linseed oil before using it.
To unstring the bow hold it as in stringing, then press down the
upper limb exactly as before, and as if you wished to place the eye
of the string in a higher notch. This will loose the string and liberate
the eye, when it must be lifted out of the notch by the forefinger,
and suffered to slip down the limb.
Before using the bow hold it in a perpendicular direction, with the
string toward you, and see if the line of the string cuts the middle of
the bow. If not, shift the eye and noose of the string to either side,
so as to make the two lines coincide. This precaution prevents a very
common cause of defective shooting, which is the result of an
uneven string throwing the arrow on one side. After using it unstring
it, and at a large shooting-party unloose your bow after every round.
Some bows get bent into very unmanageable shapes.
The general management of the bow should be on the principle that
damp injures it, and that any loose floating ends interfere with its

shooting. It should therefore be kept well varnished, and in a
waterproof case, and it should be carefully dried after shooting in
damp weather. If there are any ends hanging from the string cut
them off close, and see that the whipping, in the middle of the
string, is close and well-fitting. The case should be hung up against a
dry, internal wall, not too near the fire. In selecting your bow be
careful that it is not too strong for your power, and that you can
draw the arrow to its head without any trembling of the hand. If this
cannot be done after a little practice, the bow should be changed for
a weaker one; for no arrow will go true, if it is discharged by a
trembling hand. If an arrow has been shot into the target on the
ground, be particularly careful to withdraw it by laying hold close to
its head, and by twisting it around as it is withdrawn, in the direction
of its axis. Without this precaution it may be easily bent or broken.
In shooting at the target the first thing is to nock the arrow, that is,
to place it properly on the string. In order to effect this, take the
bow in the left hand, with the string toward you, the upper limb
being toward the right. Hold it horizontally while you take the arrow
by the middle; pass it on the under side of the string and the upper
side of the bow, till the head reaches two or three inches past the
left hand. Hold it there with the forefinger or thumb, while you
remove the right hand down to the neck; turn the arrow till the cock
feather comes uppermost, then pass it down the bow, and fix it on
the working part of the string. In doing this all contact with the
feathers should be avoided, unless they are rubbed out of place,
when they may be smoothed down by passing them through the
hand.
The body should be at right angles with the target, but the face
must be turned over the left shoulder, so as to be opposed to it. The
feet must be flat on the ground, with the heels a little apart, the left
foot turned toward the mark. The head and chest inclined a little
forward so as to present a full bust, but not bent at all below the
waist. Draw the arrow to the full length of the arm, till the hand
touches the shoulder, then take aim. The loosing should be quick,

and the string must leave the fingers smartly and steadily. The bow-
head must be as firm as a vise, no trembling allowed.
The rules of an Archery Club are usually that a Lady Paramount be
annually elected; that there be a President, Secretary, and Treasurer;
that all members intending to shoot shall appear in the uniform of
the club, and that a fine shall be imposed for non-attendance.
The Secretary sends out cards at least a week before each day of
meeting, acquainting members with the place and hour.
There are generally four prizes for each meeting, two for each sex,
the first for numbers, the second for hits. No person is allowed to
take both on the same day. A certain sum of money is voted to the
Lady Paramount, for prizes for each meeting.
In case of a tie for hits, numbers decide, and in case of a tie for
numbers, hits decide. The decision of the Lady Paramount is final.
There is also a challenge prize, and a commemorative ornament is
presented to the winner of this prize.
The distance for shooting is sixty or one hundred yards, and five-feet
targets are used.
The dress or uniform of the club is decided by the Lady Paramount.
The expenses of archery are not great, about the same as lawn
tennis, although a great many arrows are lost in the course of the
season. Bows and other paraphernalia last a long time. The lady
archers are apt to feel a little lame after the first two or three essays,
but they should practise a short time every morning, and always in a
loose waist or jacket. It will be found a very healthy and
strengthening practice and pastime.
We must not judge of the merits of ancient bowmen from the
practice of archery in the present day. There are no such distances
now assigned for the marks as we find mentioned in old histories or
poetic legends, nor such precision, even at short lengths, in the

direction of the arrow. Few, if any, modern archers in long shooting
reach four hundred yards; or in shooting at a mark exceed eighty or
a hundred. Archery has been since the invention of gunpowder
followed as a pastime only. It is decidedly the most graceful game
that can be practised, and the legends of Sherwood Forest, of Maid
Marion, Little John, Friar Tuck, and the Abbot carry us back into the
fragrant heart of the forest, and bring back memories which are
agreeable to all who have in them a drop of Saxon blood.
The usual dress is the Lincoln green of Robin Hood and his merry
men, and at Auburn in New York they have a famous club and
shooting ground, over the gate of which is painted this motto:—
What is hit is history,
And what is missed is mystery.
The traveller still sees in the Alpine Tyrol, and in some parts of
Switzerland, bands of archers who depend on the bow and arrow for
their game. But there is not that skill or that poetry attached to the
sport which made Locksley try conclusions with Hubert, in the
presence of Prince John, as we read in the immortal pages of
Ivanhoe.
The prize was to be a bugle horn mounted with silver, a silken baldric
richly ornamented, having on it a medallion of Saint Hubert, the
patron of sylvan sport. Had Robin Hood been beaten he would have
yielded up bow, baldric, and quiver to the provost of the sports; as it
was, however, he let fly his arrow, and it lighted upon that of his
competitor, which it split to shivers.

THE SEASON, BALLS, AND RECEPTIONS.
Good-night to the season! the dances,
The fillings of hot little rooms,
The glancings of rapturous glances,
The flarings of fancy costumes,
The pleasures which fashion makes duties,
The phrasings of fiddles and flutes,
The luxury of looking at beauties,
The tedium of talking to mutes,
The female diplomatists, planners
Of matches for Laura and Jane,
The ice of her Ladyship's manners!
The ice of his Lordship's champagne.
The season in London extends from May to August, often longer if
Parliament is in session. In Paris it is from May to the Grand Prix,
when it is supposed to end, about the 20th of June. In New York and
Washington it is all winter, from November 1st to Lent, with good
Episcopalians, and from November to May with the rest of mankind.
It then begins again in July, with the people who go to Newport and
to Bar Harbor, and keeps up until September, when comes in Tuxedo
and the gayety of Long Island, and the Hudson. Indeed, with the
gayety of country-house life, hunting, lawn tennis and driving, it is
hard to say when the American season ends.

There is one sort of entertainment which is a favourite everywhere
and very convenient. It is the afternoon reception or party by
daylight. The gas is lighted, the day excluded, the hostess and her
guests are in beautiful toilets; their friends come in street dresses
and bonnets; their male friends in frock coats. This is one of the
anomalies of fashion. These entertainments are very large, and a
splendid collation is served. The form of invitation is simply—
Mrs. Brownton at home
Thursday, from 3 to 6.
and unless an R. S. V. P. is appended, no reply is expected. These
receptions are favourites with housekeepers, as they avoid the
necessity of keeping the servants up at night.
The drawback to this reception is that, in our busy world of America,
very few men can spare the time to call in the daytime, so the
attendance is largely feminine.
On entering, the guest places a card on the table, or, if she cannot
be present, she should send a card in an envelope.
After these entertainments, which are really parties, a lady should
call. They are different things entirely from afternoon tea, after
which no call is expected. If the reception is given to some
distinguished person, the lady stands beside her guest to present all
the company to him or her.
If on the card the word Music is added, the guests should be
punctual, as, doubtless, they are to be seated, and that takes time.
No lady who gives a musicale should invite more than she can seat
comfortably; and she should have her rooms cool, and her lights soft
and shaded.
People with weak eyes suffer dreadfully from a glare of gas, and
when music is going on they cannot move to relieve themselves. The
hostess should think of all this. Who can endure the mingled misery

of a hot room, an uncomfortable seat, a glare of gas, and a
pianoforte solo?
A very sensible reformation is now in progress in regard to the
sending of invitations and the answering of the same. The post is
now freely used as a safe and convenient medium, and no one feels
offended if an invitation arrives with a two-cent stamp on the
envelope. There is no loss of caste in sending an invitation by post.
Then comes the ball, or, as they always say in Europe, the dance,
which is the gayest of all things for the débutante. The popular form
for an invitation to an evening party is as follows:—
Mrs. Hammond
Requests the pleasure of
Mr. and Mrs. Norton's company
on Tuesday evening, December
23, at 9 o'clock.
R. S. V. P. D
ancing.
The card of the débutante, if the ball is given for one, is enclosed.
If a hostess gives her ball at some public place, like Delmonico's, she
has but little trouble. The compliment is not the same as if she gave
it in her own house, however. If there is room, a ball in a private
house is much more agreeable, and a greater honour to the guest.
Gentlemen who have not an acquaintance should be presented to
the young dancing set; but first, of course, to the chaperon. As,
however, the hostess cannot leave her post while receiving, she
should have two or three friends to help her. Great care should be
taken that there be no wall-flowers, no neglected girls. The non-
dancers in an American ball are like the non-Catholics in a highly
doctrinal sermon: they are nowhere, pushed into a corner where
there is perhaps a draught, and the smell of fried oysters. Such is
the limbo of the woman of forty or over, who in Europe would be the
belle, the person just beginning to have a career. For it is too true

that the woman who has learned something, who is still beautiful,
the woman who has maturity and experience, is pushed to the wall
in America, while in Europe she is courted and admired. Society
holds out all its attractive distractions and comforts to such a woman
in Europe; in America it keeps everything, even its comforts, for the
very young.
The fact that American ballrooms, or rather the parlours of our
ordinary houses, are wholly disproportioned to the needs of society,
has led to the giving of balls at Delmonico's and other public places.
If these are under proper patronage there is no reason why they
should not be as entertaining, as exclusive, and as respectable as a
ball at home. Any hostess or group of managers should, if they give
up a ball at home and use the large accommodations of Delmonico
or the Assembly Rooms, certainly consider the claims of chaperons
and mammas who must wearily sit through the German. It is to be
feared that attention to the mamma is not yet a grace in which even
her daughter excels. Young men who wish to marry mademoiselle
had better pay her mother the compliment of getting her a seat, and
social leaders should also show her the greatest attention, not alone
from the selfish reason which the poet commemorates:—
Philosophy has got a charm,—
I thought of Martin Tupper,—
And offering mamma my arm,
I took her down to supper.
I gave her Pommery, Côte d'Or,
Which seethed in rosy bubbles;
I called this fleeting life a bore,
The world a sea of troubles.
It is to be feared that the life of a chaperon in America is not a bed
of roses, even if softened by all these attentions.

Kept up late, pushed into a corner, the mother of a society girl
becomes only a sort of head-chambermaid. Were she in Europe, she
would be the person who would receive the compliments and the
attention and be asked to dance in the German.
A competent critic of our manners spoke of this in the following
sensible words:—
The evils arising from the excessive liberty permitted to American
girls cannot be cured by laws. If we ever root them out we must
begin with the family life, which must be reformed. For young
people, parental authority is the only sure guide. Coleridge well said
that he who was not able to govern himself must be governed by
others; and experience has shown us that the children of civilized
parents are as little able to govern themselves as the children of
savages. The liberty or license of our youth will have to be curtailed,
as our society is becoming more complex and artificial, like older
societies in Europe. The children will have to approximate to them in
status, and parents will have to waken to a sense of their
responsibilities, and subordinate their ambitions and their pleasures
to their duties. Mothers should go out more with their daughters,
join in their pleasures, and never permit themselves to be shelved.
Society is in a transition state in America. In one or more cities of the
West and South it is considered proper for a young man to call for a
young girl, and drive with her alone to a ball. In Northern cities this
is considered very bad form. In Europe it would be considered a
vulgar madness, and a girl's character compromised. Therefore it is
better for the mother to keep her rightful place as guardian,
chaperon, friend, no matter how she is treated.
Women are gifted with so much tact and so intuitive a faculty, that in
the conduct of fashionable life they need but few hints.
The art of entertaining should be founded first, on good sense, a
quiet considerateness, a good heart, a spirit of friendliness; next, a
consideration of what is due to others and what is due to one's self.

There is always a social conscience in one's organization, which will
point aright; but the outward performance of conventional rules can
never be thoroughly learned, unless the heart is well-bred.
Many ladies are now introducing dancing at crowded day receptions
and teas. Where people are coming and going this is objectionable,
as the hostess is expected to do too much, and the guests being in
street dress, while the hostess and her dancers are in low evening
dress, the appearance of the party is not ornamental.
Evening parties are far more formal, and require the most elaborate
dress. Every lady who can wear a low-necked dress should do so.
The great drawback in New York is now the ridiculous lateness of the
hour—eleven or twelve—at which the guests arrive.
If a card is written,—
Mrs. Brown at home Tuesday evening,
some sticklers for etiquette say that she should not put R. S. V. P. on
her card.
If she wishes an answer, she should say,—
Mrs. Brown
requests the pleasure of
Mr. and Mrs. Campbell's company.
R. S. V. P.
Perhaps the latter is better form. It is more respectful. The At
Home can be used for large and informal receptions, where an
individual acceptance is not required.
Garden parties are becoming very fashionable at watering-places, in
rural cities, and at country houses which are accessible to a town. No
doubt the garden party is a troublesome affair in a climate so
capricious as ours. The hostess has to be prepared for a sudden
shower, and to have two tables of refreshments. The effort to give

the out-of-door plays in this country, as in England, has often been
frustrated by a sudden shower, as at Mrs. Stevens' palace at Castle
Point. It is curious that they can and do give them in England, where
it always rains. However, these entertainments and hunting remain
rather as visitors than as old and recognized institutions.
Americans all dance well, and are always glad to dance. Whether it
be assembly, hunt ball, or private party, the German cotillion finishes
the bail. It is an allegory of society in its complicated and bewildering
complications, its winding and unwinding of the tangled chain.
In every large city a set arises whose aim is to be exclusive.
Sometimes this privilege seems to be pushed too far. Often one is
astonished at the black sheep who leap into the well-defended
enclosures. In London, formerly, an autocratic set of ladies, well
known as Almacks, turned out the Duke of Wellington because he
came in a black cravat. In our republican country perpetual Almacks
arise, offensive and defensive,—a state of things which has its
advantages and disadvantages. It keeps up an interest in society. It
is like the fire in the engine: it makes the train move, even if it sends
out smoke and cinders which get into people's eyes and make them
weep. It is a part of the inevitable friction which accompanies the
best machinery; and if they have patience, those who are left out
one winter will be the inside aristocrats of the next, and can leave
somebody else out.
Quadrilles, the Lancers, and occasionally a Virginia Reel, are
introduced to make the modern ball more interesting, and enable
people who cannot bear the whirl of the waltz to dance. The elderly
can dance a quadrille without loss of breath or dignity. Indeed, the
Americans are the only people who relegate the dance to the young
alone. In Europe the old gray-head, the old mustache, leads the
German. Ambassadors and generals, princes and potentates, go
spinning around with gray-haired ladies until they are seventy.
Grandmothers dance with their grandsons. Socrates learned to
dance. In Europe it is the elderly woman who receives the most
flattering invitations to lead the German. An ambassadress of fifty

would be very much astonished if the prince did not ask her to
dance.
The saltatory art is like the flight of a butterfly,—hard to describe,
impossible to follow. The valse à deux temps keeps its precedence in
Europe as the favourite measure, varied with galop, polka, and polka
mazourka. We add, in America, Dancing in the Barn, which is really a
Spanish dance.
The Pavanne is worthy of study, and the Minuet de la Cour is a
stately and beautiful thing, quite worthy of being learned, if it only
teaches our women how to make a courtesy.
Each leader of the German is a potentate; he leads his troops
through new evolutions, and into combinations so vast, varied, and
changeful that it is impossible to do more than hint at them.
The proper name for a private ball is a dance. In London one never
talks of balls; it is always a dance. Although supper is served
generally at a buffet, yet some leaders, with large houses, are
introducing little tables, which are more agreeable, but infinitely
inconvenient. The comfort, however, of being able to sit while eating,
and the fact that a party of four or six may enjoy their supper
together would certainly determine the question as to its
agreeableness. This is a London fashion, one set succeeding another
at the same table. It can only be carried out, however, in a very
large house or public place. The ball suppers in New York—indeed,
all over America—are very gorgeous feeds compared with those
one sees in Europe. The profusion of flowers, the hot oysters, boned
turkey, terrapin, and canvas-back duck, the salmon, the game
patties, salads, ices, jellies, and creams, all crowded in, sweetbreads
and green peas, filet de bœuf, constant cups of bouillon,—one feels
Carlyle's internal rat gnawing as one reads of them,—the
champagne, the punch, the fine glass, choice china, the drapery of
German looms, the Queen Anne silver, the porcelain of Sèvres and
Dresden, the beauty of the women, the smart dressing, make the

ball supper an elegant, an amazing, a princely sort of sight, saving
that princes do not give such feasts,—only Americans.

WEDDINGS.
Rice and slippers, slippers and rice!
Quaint old symbols of all that's nice
In a world made up of sugar and spice,
With a honeymoon always shining;
A world where the birds keep house by twos,
And the ring-dove calls, and the stock-dove coos,
And maids are many, and men may choose,
And never shall love go pining!
If there were no weddings, there would be no art of entertaining. It
is the key-note, the initial letter, the open sesame, of the great
business of society. Therefore certain general and very, perhaps,
unnecessary hints as to the conduct of weddings in all countries may
not be out of place here.
In London a wedding in high life—or, as the French call it, higlif—is
a very sweeping affair. If we were to read the descriptions in the
Court Journal of one wedding trousseau alone, furnished to a royal
princess, or to Lady Gertrude Somebody, we should say with Fielding
that dress is the principal accomplishment of men and women. As
for the wedding-cake which is built at Gunter's, it is a sight to see,—
almost as big as Mont Blanc.
The importance of Gunter is assured by the Epicure's Almanac,
published in 1815; and for many years this firm supplied the royal

family. When George III. was king, the royal dukes stopped to eat
Gunter's pies, in gratitude for the sweet repasts furnished them in
childhood; but now the Buzzards, of 197 Oxford Street, also are
specialists in wedding-cakes.
Leigh Hunt, in one of his essays, described one Trumbull Walker as
the artist who confined himself to that denomination, meaning
wedding-cake. His mantle fell on the Buzzards.
This enormous cake, and the equally enormous bouquet are the
chief distinctive marks in which a London wedding differs from ours.
To be legal, unless by special license, weddings in England must be
celebrated before twelve o'clock. The reason given for this law is that
before 1820 gentlemen were supposed to be drunk after that hour,
and not responsible for what they promised at the altar.
In France, a singular difference of dress on the part of the groom
exists. He always wears a dress-coat and white cravat, as do all his
ushers and immediate friends. It looks very strange to English and
American eyes.
How does a wedding begin? As for the premonitory symptoms, they
are in the air for several weeks. It is whispered about amongst the
bridesmaids; it gets into the papers. It would be easy to write a
volume, and it would be a useful volume if it brought conviction to
the hearts of the offenders, of the wrong done to young ladies by
the newspapers who assume, without authority, to publish the news
of an engagement. Many a match has been broken off by such a
premature surmise, and the happiness of one or more persons
injured for life.
Young people like to approach this most important event of their
lives in a mutual confidence and secrecy; consequently society
newspapers should be very careful how they either report an
engagement, or declare that it is off. Sometimes rumors prejudicial
to the gentleman are circulated without sufficient reason, and of
course much ill-feeling is engendered.

The first intimation of an engagement should come from the bride's
mother, and the young bride fixes the day of her wedding herself.
Then the father and mother, or guardians, of the young lady issue
cards, naming the day and hour of the wedding.
Brides often give the attendant maidens their dresses; or if they do
not choose to do this, they suggest what they shall wear.
Six ushers generally precede the party into the church, after having
seated the guests. These are generally followed by six bridesmaids,
who walk two and two. No one wears a veil but the bride herself,
who enters on her father's arm. Widows who marry again must not
wear white, or veils. The fact that the bride is in white satin, and
often with low neck and short sleeves, and the groom in full morning
costume, is much criticised in France.
If the wedding occurs in the evening, the groom must wear a dress-
coat and white tie.
The invitations to the wedding are very simple and explicit:—
General and Mrs. Brounlow
Request the pleasure of your company
at the marriage of their daughter
Exclairmonde
to
Mr. Gerald FitzGerald,
on Thursday, June 16th, at 12 o'clock,
St. Peter's Church.
In asking a young lady to be her bridesmaid, the bride is supposed
to be prompted by claims of relationship or friendship, although
fashion and wealth and other considerations often influence these
invitations. As for the ushers, they must be unmarried men, and are
expected to manage all matters at the church.
Music should play softly during the entrance of the family, before the
service. The mother of the bride, and her nearest relatives, precede

her into the church, and are seated before she enters, unless the
mother be a widow and gives the bride away. The ceremony should
be conducted with great dignity and composure on all sides; for
exhibitions of feeling in public are in the worst possible taste. At the
reception, the bride's mother yields her place as hostess for the
nonce, and is addressed after the bride.
After two hours of receiving her friends, the young wife goes
upstairs to put on her dress for the journey, which may be of any
colour but black. Perhaps this is the time for a few tears, as she
kisses mamma good-by. She comes down, with her mother and
sisters, meets the groom in the hall, and dispenses the flowers of her
bouquet to the smiling maidens, each of whom struggles for a
flower.
The parents of the bride send announcement cards to persons not
invited to the wedding.
Dinners to the young pair succeed each other in rapid succession.
For the first three months the art of entertaining is stretched to its
uttermost.
A widow, in marrying again, should not use the name or initials of
her late husband. If she was Mary Steward, and had married Mr.
Hamilton, and being his widow, wishes to marry James Constable,
her cards should read:

Mr. and Mrs. Steward
Request the pleasure of your company
at the marriage of their daughter
Mary Steward-Hamilton
to
Mr. James Constable.
If she is alone, she can invite in her own name as Mrs. Mary Steward
Hamilton; or better still, a friend sends out the cards in her own
name, with simply the cards of Mrs. Mary Steward Hamilton, and of
the gentleman whom she is to marry.
The custom of giving bridal presents has grown into an outrageous
abuse of a good thing. There has grown up a rivalry between
families; and the publicity of the whole thing, its notoriety and
extravagance, ought to be well rebuked.
At the wedding refreshment-table, the bride sometimes cuts the
cake and allows the young people to search for a ring, but this is
rather bad for the gloves.
At a country wedding, if the day is fine, little tables are set out on
the lawn. The ladies seat themselves, the gentlemen carry
refreshments to them. The piazzas can be decorated with autumn
boughs, evergreens, and flowers; the whole thing becomes a
garden-party, and even the family dogs should have a wreath of
white flowers around their necks.
Much ill feeling is apt to be engendered by the distinction which is
inevitably made in leaving out the friends who feel that they were
entitled to an invitation to the house. It is better to offend no one on
so important an occasion.
Wedding-cards and wedding stationery should be simple, white
without glaze, and with no attempt at ornamentation.
It is proper for the bride to have her left hand bare as she walks to
the altar, as it saves her the trouble of taking off a long glove.

Child bridesmaids are very pretty and very much in favour. These
charming children, covered with flowers and looking very grave and
solemn, are the sweetest of heralds for a wedding procession.
There is not, however, much difficulty except when Protestant
marries Catholic. Such a marriage cannot be celebrated at the High
Altar; it leads to a house wedding which is in the minds of many
much more agreeable, as saving the bride the journey to church. In
this matter, one of individual preference of course, the large and
liberal American mind can have a very wide choice.
In France the couple must go to the Mairie, where an official in a
tricolour scarf, looking like Marat, marries them. This is especially the
case if husband or wife is a divorced person, the Catholic church
refusing to marry such. It is a curious fact, that in Catholic Italy a
civil marriage is the only legal marriage; therefore good Catholics are
all married twice. A mixed marriage in Catholic countries is very
difficult; but in our country, alas! the wedding knot can be untied as
easily as it is tied.
This train waits twenty minutes for divorces is a joke founded on
fact.
What do divorcées do with their wedding presents? has been a
favourite conundrum of late, especially with those sent by the
friends of the husband.
If an evening wedding takes place in a church those who are asked
to the house afterwards should go without bonnets. Catholic ladies,
however, must always cover their heads in church; so they throw a
light lace or mantilla over the head.
It is not often that the bride dances at her own wedding, but there is
no reason why she should not.
'Tis custom that makes cowards of us all. One brave girl was
married on a Saturday in May, thus violating all the old saws and
superstitions. She has been happy ever afterwards. Marriages in May

used to be said to lead to poverty. It is the month of Mary, the
Virgin, therefore Catholics object.
One still braver bride chose Friday; this is hangman's day, and also
the day of the crucifixion, therefore considered unlucky by the larger
portion of the human race.
However, marriage is lucky or unlucky as the blind goddess pleases;
no foresight of ours can make it a certainty. Sometimes two very
doubtful characters make each other better, and live happily; again
two very fine characters but help to sublimate each other's misery.
Perhaps no more hopeless picture of this failure was ever painted
than the misery of Caroline and Robert Elsmere, in that masterly
novel which led you nowhere.
There is a capital description of a French bourgeoise wedding in one
of Daudet's novels:—
The least details of this important day were forever engraved on
Risler's mind.
He saw himself at daybreak pacing his bachelor chamber, already
shaved and dressed, with two pairs of white gloves in his pocket.
Then came the gala carriages, and in the first one, the one with
white horses, white reins, and a lining of yellow satin, his bride's veil
floated like a cloud.
Then the entrance to the church, two by two, with this white cloud
always at their head, floating, light, gleaming; the organ, the verger,
the sermon of the curé, the tapers twinkling like jewels, the spring
toilets, and all the world in the sacristie—the little white cloud lost,
engulfed, surrounded, embraced, while the groom shook hands with
the representatives of the great Parisian firms assembled in his
honour; and the grand swell of the organ at the end, more solemn
because the doors of the church were wide open so that the whole
quarter took part in the family ceremony; the noises of the street as
the cortège passed out, the exclamations of the lookers-on,—a
burnisher in a lustring apron crying aloud, 'The groom is not

handsome, but the bride is stunning,'—all this is what makes one
proud when he is a bridegroom.
Then the breakfast at the works, in a room ornamented with
hangings and flowers; the stroll in the Bois, a concession to the
bride's mother, Madame Chèbe, who in her position as a Parisian
bourgeoise would not have considered her daughter married without
the round of the lake and a visit to the cascade; then the return for
dinner just as the lights were appearing on the Boulevard, where
every one turned to see the wedding party, a true, well-appointed
party, as it passed in a procession of liveried carriages to the very
steps of the Café Vefour.
It was all like a dream.
Now, dulled by fatigue and happiness, the worthy Risler looked
dreamily at the great table of twenty-five covers, with a horseshoe
at each end. Around it were well-known, smiling faces in whose eyes
he seemed to see his own happiness reflected. Little waves of
conversation from the different groups drifted across the table; faces
were turned toward one another. You could see here the white cuffs
of a black suit behind a basket of asclepias, here the laughing face
of a girl above a dish of confections. The faces of the guests were
half hidden behind the flowers and the dessert; all around the board
were gayety, light, and colour.
Yes, Risler was happy.
Aside from his brother Franz, all whom he loved were there. First
and foremost, facing him, was Sidonie,—yesterday the little Sidonie,
to-day his wife. She had laid aside her veil for dinner, she had
emerged from the white cloud.
Now in her silken gown, white and simple, her charming face
seemed more clear and sweet under the carefully arranged bridal
wreath.

By the side of Risler sat Madame Chèbe, the mother of the bride,
who shone and glistened in a dress of green satin gleaming like a
shield. Since morning all the thoughts of the good woman had been
as brilliant as her robe. Every moment she had said to herself, 'My
daughter is marrying Fremont and Risler,'—because in her mind it
was not Risler whom her daughter married, but the whole
establishment.
All at once came that little movement among the guests that
announces their leaving the table,—the rustle of silks, the noise of
chairs, the last words of talk, laughter broken off. Then they all
passed into the grand salon, where those invited were arriving in
crowds, and, while the orchestra tuned their instruments, the men
with glass in eye paraded before the young girls all dressed in white
and impatient to begin.

HOW ROYALTY ENTERTAINS.
Stand back, and let the King go by.—Old Play.
Thrones, dominations, princedoms, virtues, powers.
When we approach the subject of royal entertainments, we cannot
but feel that the best of us are at a disadvantage. Princes have
palaces and retainers furnished for them. They have a purse which
knows no end. They are either by the divine right, or by lucky
chance, the personages of the hour! It is only when one of them
loses his head, or is forced to abdicate, or falls by the assassin's
dagger, that they approach at all our common humanity.
Doubtless to them, entertaining, being a perfunctory affair, becomes
very tedious. Pomp is not an amusing circumstance and they get so
tired of it all that when off duty kings and queens are usually the
most plainly dressed and the most simple of mortals. The age of
strut has passed away. No one cares to assume the puffiness of
Louis XIV. or George IV.
Royal entertainments, however, have this advantage, they open to
the observer the historical palace, and the pictures, gems of art, and
interesting collections of which palaces are the great conservators.
It would seem that Louis XIV., called le Grand Monarque, Louis the
Magnificent, was a master of the art of entertaining. Under him the

science of giving banquets received, in common with the other
sciences, a great progressive impulse. There still remains some
memory of those festivals, which all Europe went to see, and those
tournaments, where for the last time shone lances and knightly suits
of armour. The festivals always ended with a sumptuous banquet,
where were displayed huge centre-pieces of gold and silver, painting,
sculpture, and enamel, all laudatory of the hero of the occasion.
This fashion made the fame of Benvenuto Cellini in the previous
century. To-day, monarchs content themselves with having these
centre-pieces made of cake, sugar, or ices. There will be no record of
their great feasts for future ages.
Toward the end of the reign of Louis XIV., the cook, the cordon bleu,
received favourable notice; his name was written beside that of his
patron; he was called in after dinner. It is mentioned in some of the
English memoirs that this fashion was not unknown so lately as fifty
years ago in great houses in England, where the cook was called in,
in his white cap and apron, publicly thanked for his efforts, and a
glass of wine offered him by his master, all the company drinking his
health. This must have had an excellent effect on the art of
gastronomy.
Madame de Maintenon, whose gloomy sway over the old king
reduced the gay court to the loneliness of an empty cathedral, threw
a wet napkin on the science of good eating, and put out the kitchen
fires for a season.
Queen Anne, however, was fond of good cheer, and consulted with
her cook. Many cookery books have the qualification after Queen
Anne's fashion.
Under the Regent Orléans, a princely prince in spite of his faults, the
art of good eating and entertaining was revived; and he has left a
reputation for piqués of superlative delicacy, matelots of tempting
quality, and turkeys superbly stuffed.

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