coarse wavelength Division MUltiplexer Module（CWDM）optical fiber

Coarse wavelength division multiplexing (CWDM) is also known as sparse wavelength division multiplexing or thin wavelength division multiplexing.

Dense wavelength division multiplexing (DWDM) has fewer channels, but more channels than standard wavelength division multiplexing (WDM). The wavelength division multiplexing (DWDM) is a kind of optical multiplexing technology.