CWDM vs DWDM Technology
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CWDM and DWDM are both types of WDM systems that transmit multiple wavelengths of laser light through a single optical fiber. However, they differ in channel spacing, transmission reach, and cost. CWDM has a wider channel spacing of 20nm, a shorter transmission reach of 160km, and a lower cost compared to DWDM. DWDM has a narrower channel spacing of 0.2-0.8nm, can transmit signals over longer distances, and has a higher cost due to its use of temperature-controlled lasers. The key differences are that CWDM is cheaper but has lower performance, while DWDM has a higher performance but also a higher cost.
CWDM vs DWDM Technology
- 1. Comparison Between CWDM & DWDM Technology Mohamed Shaamiq 1
- 2. For a better signal transmission in fiber-optic communication, different kinds of technologies are applied to the industry. Wavelength-division multiplexing (WDM) is one of the commonly used technologies which multiplexes a number of optical carrier signals onto a single optic fiber by using different wavelengths of laser light. That is to say, WDM enables two or more than two wavelength signals to transmit through different optical channels in the same optical fiber at the same time. Mohamed Shaamiq 2
- 3. • There are two types of divisions WDM system- • CWDM (coarse wavelength division multiplexing) • DWDM (dense wavelength division multiplexing). • They are both using multiple wavelengths of laser light for signal transmission on a single fiber. However, from the below aspects • Channel spacing, • Transmission reach, • Modulation laser • Cost, • CWDM and DWDM still have a lot of differences. This document will focus on these distinctions and hope you can have a general understanding about CWDM and DWDM technology. Mohamed Shaamiq 3
- 4. Channel Spacing • As their names suggest, the words “coarse” and “dense” reveal the difference in channel spacing. CWDM has a wider spacing than DWDM. It is able to transport up to 16 wavelengths with a channel spacing of 20 nm in the spectrum grid from 1270 nm to 1610 nm. But DWDM can carry 40, 80 or up to 160 wavelengths with a narrower spacing of 0.8 nm, 0.4 nm or 0.2 nm from the wavelengths of 1525 nm to 1565 nm (C band) or 1570 nm to 1610 nm (L band). It is no doubt that DWDM has a higher performance for transmitting a greater number of multiple wavelengths on a single fiber. Mohamed Shaamiq 4
- 6. Transmission Reach • Since the wavelengths are highly integrated in the fiber during light transmission, DWDM is able to reach a longer distance than CWDM. The amplified wavelengths provide DWDM with the ability of suffering less interference over long-haul cables. Unlike DWDM system, CWDM is unable to travel unlimited distance. The maximum reach of CWDM is about 160 kilometers but an amplified DWDM system can go much further as the signal strength is boosted periodically throughout the run. Mohamed Shaamiq 6
- 7. Modulation Laser • CWDM system uses the uncooled laser while DWDM system uses the cooling laser. Laser cooling refers to a number of techniques in which atomic and molecular samples are cooled down to near absolute zero through the interaction with one or more laser fields. Cooling laser adopts temperature tuning which ensures better performance, higher safety and longer life span of DWDM system. But it also consumes more power than the electronic tuning uncooled laser used by CWDM system. Mohamed Shaamiq 7
- 8. Cost • Because the range of temperature distribution is nonuniform in a very wide wavelength, so the temperature tuning is very difficult to realize, thus using the cooling laser technique increases the cost of DWDM system. Typically, DWDM equipment is four or five times more expensive than CWDM equipment. Mohamed Shaamiq 8
- 9. Conclusion • CWDM and DWDM are both coming from the WDM technology that is capable of conveying multiple wavelengths in a single fiber. But with different characteristics, people should think twice before choosing the CWDM or DWDM system. CWDM usually costs less but its performance is far behind DWDM. Both your requirements and budget need to be taken into consideration. Moreover, the WDM products including CWDM mux/demux module, DWDM mux/demux module and optical splitter are highly welcome in the market. Mohamed Shaamiq 9