What is WDM
WDM (optical Division Multiplexing) is the technology to combine two or more optical carrier signals of different wavelengths (carrying various information) at the transmitting end through a Multiplexer coupled to the same optical fiber for transmission. At the receiving end the optical signals of various wavelengths are separated by Demultiplexer, and then restored to the original signal by the optical receiver for further processing. The main purpose of WDM is to increase the bandwidth capacity of optical fibers. Therefore, WDM systems are widely used by telecom operators to expand capacity through WDM without laying more optical fibers.
What is CWDM, CCWDM, DWDM, FWDM, LWDM
WDM solutions include CWDM (Coarse Wavelength Division Multiplexing), CCWDM (Compact Coarse Wavelength Division Multiplexing), DWDM (Dense Wavelength Division Multiplexing), FWDM (Filter Wavelength Division Multiplexing) and LWDM (LAN Wavelength Division Multiplexing).
CWDM (Coarse Wavelength Division Multiplexer)
CWDM consists of 18 different wavelength channels spaced 20 nm apart from 1270nm to 1610nm. CWDM supports fewer channels than DWDM because it is compact and cost-effective, making it an ideal solution for short range communication. The main advantage of CWDM system is its low cost, which is reflected in filters and lasers. The wide wavelength interval of 20nm demands low technical requirement for laser and simplified structure of optical multiplexer/demultiplexer for CWDM. With simplified structure and improved yield, the cost is reduced.
DWDM (Dense Wavelength Division Multiplexer)
The channel spacing of DWDM is 1.6/0.8/0.4 nm (200GHz/100 GHz/50 GHz), much narrower than that of CWDM. Compared with CWDM, DWDM has dense wavelength spacing and can support 8 to 160 wavelengths on one optic fiber, very sui for long-haul transmission. Combined with EDFA, DWDM system can work within a range of thousands of kilometers. Read more on WDM, CWDM, CCWDM, DWDM, FWDM, LWDM Multiplexer.
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