Wavelength Division
Multiplexing (WDM)
WDM is the term used to describe the multiplexing of several digital channels
into one fibre by the use of two or more wavelengths to carry signals through
the same optical fibre. Signals are generated with different light sources,
combined for transmission then at the other end separated optically before
being detected [Hecht, p129]. WDM is not widely used today [Hecht, p129]
but it is still widely considered as it has the ability to multiply the
capacity of existing fibre optic cables. Shown below is a diagram of two
methods of implementing WDM systems [Yeh, pg252].
