Patent ID: 6978090

Claim:
A communications network for connecting a plurality of nodes, the network comprising: first, second, third and fourth optical networks each arranged to be capable of carrying a respective first, second, third and fourth set of channels, said first and second sets of channels being carried in an opposite direction to said third and fourth sets of channels with respect to said nodes, said first and third optical networks each comprising a plurality of splitters serially connected by optical waveguides such that an output port of one of said respective splitters is connected to an input port of another of said respective splitters, and wherein a non-serially connected output port of one of said splitters forms an output of one of said nodes; said second and fourth optical networks each comprising a plurality of couplers serially connected by optical waveguides such that an output port of one of said respective couplers is connected to ad input port of another of said respective couplers, and wherein a non-serially connected input port of one of said respective couplers forms an input of one of said nodes.