What are the differences between CWDM devices and DWDM devices?

In the construction of MAN, WDM equipment is an important part, mainly CWDM coarse WDM equipment and DWDM dense WDM equipment, so what are the differences between the two? In this article, ETU-LINK will explain the differences between CWDM devices and DWDM devices.

1. Different optical modules are used

CWDM coarse wave division multiplexer & demultiplexer uses CWDM optical module, while DWDM coarse wave division multiplexer & demultiplexer uses DWDM optical module.

2. Different channel spacing

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

3. DWDM devices transmit farther than CWDM devices

Because the wavelengths of dense wavelength division multiplexing devices (DWDM) are highly integrated during fiber transmission, DWDM devices are able to transmit longer distances than CWDM devices. The 10G SFP+ CWDM optical module can transmit up to 100KM, while the 10G SFP+ DWDM optical module can transmit up to 100KM.

4, the laser index requirements are different

CWDM WDM equipment generally uses uncooled lasers, while DWDM WDM equipment needs to use cooled lasers, so as to ensure better performance, higher safety and longer service life of DWDM system.