CWDM

Coarse Wavelength-Division Multiplexing (CWDM) is a technology which multiplexes a number of optical carrier signals onto a single optical fibre by using different wavelengths (i.e., colors) of laser light.

ITU has standardized a channel spacing grid for CWDM (ITU-T G.694.2) using the wavelengths from 1271 to 1611nm with a channel spacing of 20 nm.