CWDM (coarse wavelength division multiplexing)

CWDM is a type of wave division multiplexing in which uncooled lasers are used to overlay optical light channels in a pipe. The use of uncooled lasers reduces cost, compared with dense wavelength division multiplexing, which uses cooled lasers.

In CWDM, channels are spaced farther apart than in DWDM systems. But CWDM can only scale up to five or six wavelengths, vendors and analysts say.