wavelengths (colours) of
laser light to carry different
signals.
The device that joins the signals together is known as a
device that does both and that ought to be called a "mudem"
but isn't.
The first WDM systems combined two signals and appeared around
1985. Modern systems can handle up to 128 signals and can
expand a basic 9.6
Gbps fibre system to a capacity of over
1000 Gbps.
WDM systems are popular with telecommunications companies
because they allow them to expand the capacity of their fibre
networks without digging up the road again. All they have to
do is to upgrade the (de)multiplexors at each end. However
these systems are expensive and complicated to run. There is
currently no
standard, which makes it awkward to integrate
with older but more standard
SONET systems.
Note that this term applies to an optical
carrier (which is
(which is more often described by frequency). However, since
wavelength and frequency are inversely proportional, and since
radio and light are both forms of electromagnetic radiation,
the distinction is somewhat arbitrary.
[Is "wave division multiplexing", as in "dense wave division
multiplexing" (DWDM) just a trendy abbreviation?]
(2002-07-16)