WDM is a technology to solve the shortage of optical fiber resources. Its main purpose is to increase the available bandwidth of optical fiber without laying more fibers. CWDM and DWDM are two kinds of WDM technology which are widely used in telecommunication. They are mainly used in WDM / demultiplexer. WDM / demultiplexer should be used together with WDM optical module. Next ETU-LINK will show you the difference between CWDM and DWDM optical module.

Different wavelength

The wavelength range of CWDM optical module is 1270-1610nm, and the interval between wavebands is 20nm. There are 18 channels to choose from. Generally, 1470-1610nm band is used, and the common transmission distance is 40KM, 80KM and 120KM. The transmission rates of CWDM optical module are 155M, 1.25G and 10G, which correspond to the type of SFP and SFP+ / XFP respectively.

The wavelength of DWDM optical module is located in C-band (c17-c61), the range is 1563.86-1528.77nm, and the interval between wavebands is 0.8nm. There are 45 optional channels, and the common transmission distance is 40KM and 80KM. There are two kinds of package types of 10G DWDM optical module: SFP+ and XFP.

Different application scenarios

CWDM optical module is used in metropolitan access network, enterprise network and campus network;

DWDM optical module is applied to long-distance trunk network and core node of large capacity man.

The WDM / demultiplexer used is different

CWDM optical module should be used with CWDM WDM and CWDM demultiplexer to realize optical network interconnection;

DWDM optical module should be used with DWDM WDM and DWDM demultiplexer to realize optical network interconnection.

Different lasers are used in CWDM/DWDM optical modules

In order to prevent the wavelength drift outside the filter channel of multiplexer and demultiplexer caused by temperature change, DWDM optical module needs to use cooled laser (temperature coordination), while CWDM optical module uses uncooled laser (electronic coordination).

Different cost

Under the simultaneous interpreting distance, the modulating laser of the DWDM optical module is more expensive than the CWDM optical module. Therefore, the DWDM optical module is more expensive than the CWDM optical module.