wavelength division multiplexing

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wavelength division multiplexing - Free On-line Dictionary of Computing (26 May 2007) :

  wavelength division multiplexing
  DWDM
  WDM
  
     <communications> (WDM) Multiplexing several Optical Carrier n
      signals on a single optical fibre by using different
     wavelengths (colours) of laser light to carry different
     signals.
  
     The device that joins the signals together is known as a
     multiplexor, and the one that splits them apart is a
     demultiplexor.  With the right type of fibre you can have 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
     typically described by its wavelength), whereas frequency division multiplexing
      typically applies to a radio carrier
     (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.
  
     See also time division multiplexing, code division multiplexing
     .
  
     [Is "wave division multiplexing", as in "dense wave division
     multiplexing" (DWDM) just a trendy abbreviation?]
  
     (2002-07-16)