WDM carrying schemes include coarse wavelength division multiplexing (CWDM), dense wavelength division multiplexing (DWDM), medium wavelength division multiplexing (MWDM) and fine wavelength division multiplexing (LWDM).
MWDM reuses the first 6 waves of CWDM, and compreses the wavelength interval to 7nm, and expands the left and right migration to 3.5nm to 12 waves.
LWDM is a Lan-WDM technology based on Ethernet channel, which is also known as wavelet division multiplexing.
The channel spacing is 200~800GHz, and the range is between DWDM (100GHz, 50GHz) and CWDM (about 3THz).
LWDM adopts 12 wavelengths from 1269nm to 1332nm located in the O-band (1260nm ~ 1360nm) range, with wavelength intervals of 4nm (1269.23, 1273.54, 1277.89, 1282.26, 1286.66, 1291.1, 1295.56, 1300.05, 1304.58, 1309.14, 1313.73, 1318.35nm).
LWDM's working wavelength is located near the zero dispersion, with small dispersion and good stability.
At the same time, LWDM can support 12 wave 25G, capacity increase, can further save fiber.