Dense Wavelength Division Multiplexing (DWDM)
DWDM combines many optical signals, each on a different, closely spaced wavelength, onto one fibre, multiplying its capacity.
What is Dense Wavelength Division Multiplexing (DWDM)?
DWDM uses channel spacings of 100, 50 GHz or less in the C-band around 1550 nm, giving 40 to 96 or more channels per fibre, which can be amplified together by optical amplifiers. Coarse WDM (CWDM) uses wide 20 nm spacing and up to 18 channels; it is cheaper but cannot be amplified and covers shorter distances.