What Does Coarse Wavelength Division Multiplexing (CWDM) Mean?Coarse wavelength division multiplexing (CWDM), a variant of wavelength division multiplexing (WDM), is an optical transmission technique used for shorter distances as compared to dense WDM (DWDM).
CWDM transmits few channels and makes use of wider spacing in between the channels for distances of up to 60 km. CWDM's wider spacing of up to 20 nm, when compared with DWDM's 1.6 nm, can tolerate much higher temperature fluctuations.
In 2004, IEEE standardized CWDM for 10-Gb Ethernet.
CWDM is also known as wide WDM.