Applications of wavelength routing in a core telecommunication network

Upgrade of a core telecommunications network by means of wavelength division multiplexing has not up to now appeared operationally attractive. Influential factors have been the lack of suitable wavelength defined sources and the increased losses of the multiplexing elements which limit the system range. Solutions to these problems are in the form of higher power, wavelength definable DFB lasers, higher sensitivity receivers and optical amplifiers (either semiconductor lasers or fibre types). The authors show that wavelength multiplexed systems can be interconnected to form an optical transmission network infrastructure that offers similar planning flexibility to those currently used but with increased bandwidth. With the progress of optical switching technology it is possible to foresee how flexibility can be added to these networks to provide automatic routing and protection of high capacity channels. Some network structures are examined and their attributes discussed