VLinkSys.ppt
- 1. Versatile Link System Status Report Annie Xiang on behalf of WP1.1 Group SMU Physics March, 2010 ____________________________
- 2. Versatile Link Project Description • Optical serial data link front – back end • Target data rate ~5Gbps, link reach ~150 meter • Conventional and versatile components in SFP+ package • Multi-mode (850nm) and Single-mode (1310nm) variants • Point-to-Point architecture studied first • Interface with GBT and FPGA chips ____________________________ 2 A. Xiang, SMU PHYSICS
- 3. System Study • Previously • Designed and fabricated house version SFP+ carrier boards, running up to 10Gbps • Developed test benches utilizing stand alone Bit Error Rate Tester and Stratix II GX based FPGA Bit Error Rate Tester • Characterized physical layer performance in term of transceiver waveforms, system BER scan and fiber link reach • Current • Generate detailed system level specification • Collect relevant clauses from industry standards • Customize parameters pertain to different interfaces and variants • Define system power margins • Explore link model to extract margins at target data rate and link length • Test commercial candidates to refine engineering estimation ____________________________ 3 A. Xiang, SMU PHYSICS oTx oRx oTx oRx In detector P2P
- 4. System Level Specification • Under discussion within versatile link project, emerging • Specify data flow directions and interfaces, distinguish versatile transceiver components and standard transceiver components, include SM and MM flavor ____________________________ 4 A. Xiang, SMU PHYSICS
- 5. System Level Specification • Cross reference to industrial standards IEEE 802.3ae, MSA SFF-8431, Fiber Channel FC-PI-n and FC-MSQS • Timing and jitter parameters are extracted through data rate scaling with judgmental relax/ constrain • Optical power parameters are modified per link budget page 6 - 9 • Electrical parameters are to be emerged with GBT development • The following table specifies single mode standard and versatile transceiver optical transmit interface ____________________________ 5 A. Xiang, SMU PHYSICS Parameters 10GBASE-LR 400-SM-LC-M 800-SM-LC-I VTRx/TRx-SM Average launch power (max) (dBm) 0.5 -1 0.5 -1 Average launch power (min) (dBm) -8.2 -11.2 -10.6 -8.2 OMA min (mW/dBm) -5.2 .15/-8.2 .29/-5.4 -5.2 Extinction ratio (min) (dB) 3.5 - 3.5 3.5 RIN12OMA (max) (dB/Hz) -128 -120 -128 -128 Transmitter eye mask definition See plot See plot See plot 4GFC scale Transmitter & dispersion penalty (max) (dB) 3.2 - 3.2 (1) Rise/Fall Time (20%-80%) (ps) - 90 - 76 Total Jitter UIp-p - 0.44 - 0.44 Deterministic Jitter UIp-p - 0.26 - 0.26
- 6. Link Budget • Optical power budget is expensed among attenuation, insertion loss, power penalties and margin • Power penalties are allocated for link impairments such as noise and dispersion • Contributors to power penalties include inter-symbol interference, mode partition noise (MM), relative intensity noise, reflection noise (SM), etc. • Irradiation degradations are specific only in our applications. ____________________________ 6 A. Xiang, SMU PHYSICS
- 7. Link Budget ____________________________ • Three scenarios fit budget, but MM-downlink requires more power, or • Use in outer range (>40cm radius) to reduce rad-penalties, or, • Pick components to comply with a tighter specification, i.e., Tx OMA Parameters MM-uplink MM-downlink SM-uplink SM-downlink Transmit OMA min -3.8dBm -3.8dBm -3.2dBm -3.2dBm Receiver sensitivity OMA max -11.1dBm -11.1dBm -12.6dBm -12.6dBm Power budget 7.3 dB 7.3 dB 9.4 dB 9.4dB Fiber attenuation 0.6dB 0.6dB 0.1dB 0.1dB Connection and splice loss 1.5dB 1.5dB 2dB 2dB Allocation for penalties 5.2 dB 5.2 dB 7.3 dB 7.3 dB TDP and other penalties 1 dB 1 dB 1.5 dB 1.5 dB Tx radiation penalties - - - - Rx radiation penalties - 7dB - 5 dB Fiber radiation penalties (cold) 1.0dB 1.0dB - - Meet budget Ok not yet Ok Ok Safety margin 3.2dB -3.8dB 5.8dB 0.8dB 7 A. Xiang, SMU PHYSICS
- 8. Link Budget • In FC and GbE standards, two specifications are developed to assure BER performance, guarding against worst case physical media impairments • Transmitter and Dispersion Penalty test emulates worst case transmitter and fiber plant • Stress test emulates worst case optical input to receiver • Both require advanced equipment that we do not have ____________________________ 8 A. Xiang, SMU PHYSICS
- 9. Link Budget • A series of BER sensitivity tests are conducted to evaluate system penalty variation on • Several commercial transceiver modules • Several fiber length, patch cord combinations • System penalty variations are under 1.5dB ____________________________ 9 A. Xiang, SMU PHYSICS
- 10. Link Model • An excel spreadsheet with textbooks engineering equations • To be populated with parameter values to represent different link scenarios • Model was validated by experiments in multiple labs • Generally used for worst case analysis ____________________________ 10 J.Ye, A. Xiang, SMU PHYSICS
- 11. Link Model • Loss and penalties calculated and plotted against link length • Each physical impairment effect can be turned on/off independently • Sensitivity against several specifications studied • Penalties limit for MM link (850nm, 5Gbps, 150 meter) is set to 1dB. • Penalties limit for SM link (1310nm, 5Gbps, 150 meter) is set to 1.5dB. ____________________________ 11 A. Xiang, SMU PHYSICS MM power penalties vs. distance @10G SM power penalties vs. distance @10G Industrial limit Our appli. Industrial limit