DWDM (Dense Wavelength Division Multiplexing)

DWDM is an advanced variant of WDM in which spectral channels are spaced very densely — typically every 100, 50, or 25 GHz — enabling transmission of dozens or hundreds of independent channels through a single fiber.

How does DWDM work?

Densely packing channels requires lasers with a very stable, narrow wavelength and precise optical filters (multiplexers, demultiplexers) capable of separating channels a fraction of a nanometer apart. DWDM systems typically operate in the C-band transmission window (1530–1565 nm), where fiber attenuation and EDFA amplifiers are most effective.

Applications

DWDM is used in telecom-operator backbone networks, transatlantic and transcontinental long-haul links, and interconnects between data centers requiring terabit-per-second transmission.

Related terms

WDM

EDFA

Chromatic dispersion