Patent ID: 7634194

Claim:
A multi-channel protection switching method for mitigating the effects of wavelength and time-dependent optical propagation impairments in an optical communications system, the multi-channel protection switching method comprising: monitoring a pre-forward error correction bit error rate of each of a plurality of working channels and each of a plurality of protection channels; if the monitored pre-forward error correction bit error rate of one of the plurality of working channels exceeds a predetermined threshold and the pre-forward error correction bit error rate of one of the plurality of protection channels does not exceed the predetermined threshold, switching traffic from said one of the plurality of working channels to said one of the plurality of protection channels; and monitoring a post-forward error correction bit error rate of each of the plurality of working channels and each of the plurality of protection channels; wherein switching the traffic from said one of the plurality of working channels to said one of the plurality of protection channels occurs if the monitored pre-forward error correction bit error rate of said one of the plurality of working channels exceeds the predetermined threshold, the pre-forward error correction bit error rate of said one of the plurality of protection channels does not exceed the predetermined threshold, and the monitored post-forward error correction bit error rate of said one of the plurality of working channels is zero.