How does WDM work?
Wavelength division multiplex is referred to as WDM, which combines multiple signals at various wavelengths for simultaneous transmission over a single fiber optic cable. It usually has Multiplexer and Demultiplexer. Multiplexer (MUX) combines wavelengths at the transmitter, and the Demultiplexer(DEMUX) at the receiver separates the individual wavelengths. The main purpose of WDM is to increase the available bandwidth of fiber-optic cable. The capacity of a fiber can be increased tremendously simply by upgrading the multiplexer and demultiplexer on any given link. So WDM systems are popular with telecommunications companies because they allow them to expand the capacity of the network without laying more fiber.
Two types: CWDM and DWDM
There are two types of WDM standards: CWDM - coarse wavelength division multiplexing, and DWDM - dense wavelength division multiplexing.
One of the biggest difference between CWDM and DWDM is the Channel Spacing. Channel spacing refers to the difference between the nominal carrier frequencies of two adjacent channels and can be used to prevent inter-channel interference. The CWDM wavelength set consists of a series of 18 wavelengths spaced 20nm apart, from 1270nm to 1610nm. DWDM technology packs many more wavelengths in a much narrower band of the spectrum than CWDM. DWDM can carry 40, 80 or up to 160 wavelengths with a narrower spacing of 1.6/0.8/0.4nm (200/100/50GHz). Different channel spacing also results in different bandwidth and capacity that CWDM and DWDM can carry. The DWDM module further increases the system bandwidth and capacity by using tightly spaced wavelengths to carry more signals on the same fiber.
The biggest advantage of CWDM systems is the low cost, and the component cost is mainly reflected in filters and lasers. The wide wavelength spacing of 20 nm also gives CWDM the advantage of low specification of the laser and simplified structure of the optical multiplexer/demultiplexer. The structure is simplified, the yield is improved, so the cost is reduced. DWDM is mainly due to the high cost of laser diodes and the cooling laser technology used to maintain wavelength stability.
What is CCWDM?
CCWDM is a mini-wavelength division multiplexer, which is a mini version of CWDM. CCWDM has a much smaller package size, which is 10 times smaller than the standard CWDM package. CCWDM is cheaper than CWDM and DWDM. It can replace CWDM products in telecommunications, enterprise networks, PON network, cable television and other fields.
How to choose CWDM / DWDM / CCWDM solutions should be based on their respective characteristics and differences, comprehensive consideration of the needs and budget of the application scenario to make the optimal solution.
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