WAVELENGTH DIVISION MULTIPLEX OPTICAL TELECOMMUNICATIONS NETWORK

摘要

A wavelength division multiplex (WDM) optical telecommunications network comprises a plurality of nodes (110,112,114,116) interconnected by optical fibre waveguides (4,6). Communication traffic is communicated between nodes by optical radiation modulated with the communication traffic, said radiation being partitioned into a plurality (N) of wavelength channels each channel having a discrete non-overlapping waveband (lambd1 to lambdN). Each node includes means for dropping at least one of the wavelength channels to thereby define a connection to said node and includes means for adding at least one wavelength channel to the network to define a connection to another node of the network. The network is characterised in that: at least one node (2) has ascribed to it a fixed subset (Mi) of the N wavelength channels and includes means (12:42, 44) for dropping each of the wavelength channels (lambda to lambdd) of the fixed subset (Mi) from the network. The node further comprises wavelength selectable means (14,30,32,34) capable of adding one or more of at least any of the remaining wavelength channels other than the subset to the network to define a connection to another node of the network.