Patent ID: 7302176

Claim:
A wavelength division multiplexing optical network, comprising: a client; a plurality of redundant optical paths including a working path and a protection path; and a plurality of network nodes redundantly connected through said optical paths in a predetermined configuration, at least one of said network nodes being connected to said client, said network nodes transmitting and receiving optical signals with each other at a set of wavelengths, each of said network nodes further comprising; an optical add/drop multiplexer unit for converting a client optical signal at a first channel frequency from said client to a second channel frequency at one of said wavelengths to generate a converted client optical signal, said add/drop multiplexer unit splitting the converted client optical signal into split and converted redundant client optical signals for said optical paths, said add/drop multiplexer unit selectively multiplexing the split and converted redundant client optical signals to generate a wavelength division multiplexed optical signal, said add/drop multiplexer unit selectively demultiplexing the wavelength division multiplexed optical signal to generate a wavelength division demultiplexed optical signal; an optical signal failure detector connected to each of said optical paths for detecting a failure in the wavelength division demultiplexed optical signal to generate an optical path failure signal; and an optical switch unit connected to said optical paths in response to the optical path failure signal and having a first optical switch for switching from one of said optical paths to another of said optical paths.