Method and apparatus for an optical bi-directional line switched ring

Abstract

An optical bi-directional line switched ring for performing adding and dropping of traffic into the traffic path and for performing ring and/or span protection switching. The optical bi-directional line switched ring include a plurality of nodes, each node having multiple input demultiplexer/output multiplexer sections, a command and control channel having multiple fibers, and up to N-1 slave circuits. Each multiple input demultiplexer/output multiplexer sections has an input demultiplexer to receive and demultiplex signals from a fiber and an output multiplexer to receive the demultiplexed wavelengths from internally and multiplex them into an outgoing signal. The command and control channel can be a standard bi-directional line switch that has one channel coupled to each fiber of the system. Each slave circuit comprising a plurality optical switching circuits coupled to the multiple input demultiplexer/output multiplexer sections such that the optical switching circuits are operable to carry up to N wavelengths of traffic. The command and control channel in conjunction with a SONET bi-directional line switched ring monitors the plurality of lines in the bi-directional line switched ring to control the operation of the optical add/drop multiplexer in response to the sensed signals on the plurality of lines. If a disruption of traffic occurs, the command and control channel will so indicate and will use the optical switching circuits that are slaved to it to re-route and protect traffic.