In the construction of metropolitan area network, wavelength division multiplexing equipment is an important part, mainly including CWDM coarse wavelength division multiplexing equipment and DWDM dense wavelength division multiplexing equipment, so what is the difference between the two? In this article, ETU-LINK will tell you the difference between CWDM equipment and DWDM equipment.

1. The optical modules used are different

The CWDM Demultiplexer uses CWDM optical modules, while the DWDM  Demultiplexer uses DWDM optical modules.

2. The channel spacing is different

Channel spacing is defined as the difference between the nominal carrier frequencies of two adjacent optical channels and is generally used to prevent inter-channel interference. CWDM wavelength division multiplexing equipment has a wider spacing than DWDM wavelength division multiplexing equipment, which can transmit 18 wavelengths in a spectral grid from 12701 nm to 1610 nm with a channel spacing of 20 nm. DWDM wavelength division multiplexing equipment can transmit 40, 80 or 160 wavelengths, and the channel spacing can be 0.8 nm.

3. DWDM equipment can transmit farther than CWDM equipment

Since the wavelengths of DWDM are highly integrated in the optical fiber transmission process, DWDM wavelength division multiplexing equipment can transmit longer distances than CWDM wavelength division multiplexing equipment. 10G SFP+ CWDM optical modules can transmit up to 100KM, while 10G SFP+ DWDM optical modules can transmit up to 100KM.

4. The index requirements of the laser are different

CWDM wavelength division multiplexing devices generally use uncooled lasers, while DWDM wavelength division multiplexing devices need to use cooled lasers to ensure better performance, higher safety and longer service life of DWDM systems.

5. Different equipment costs

The total cost of CWDM equipment is lower than that of DWDM equipment.

Understanding of CWDM and DWDM equipment difference, as to how to choose to use the two need to assess their own business in the future the development of the situation, thus the early stages of the decision is based on low cost with poor flexibility of CWDM wavelength division multiplexing equipment installation, or at a higher cost of initial installation flexibility is good DWDM wavelength division multiplexing equipment.