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Networking Fundamentals · Intermediate

Wavelength Division Multiplexing (WDM)

Transmitting multiple signals over one fiber by assigning each a different wavelength of light.

Definition

WDM greatly multiplies fiber capacity. Coarse WDM uses up to 18 widely spaced channels and is cost-effective for metro links, while dense WDM packs dozens to over a hundred channels closely for long-haul carriers.

Example

A metro carrier runs 40 DWDM channels of 100 Gbps over a single fiber pair.

Exam tip

WDM = frequency division for light; CWDM fewer channels, DWDM many.

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