Patent ID: 6721502
Filing Date: 2004-04-13
Classification: H04J

Abstract:
Optical signal protection apparatus for use in an optical node intended to be interconnected with a plurality of optical nodes in an optical transmission ring configuration, the optical signal protection apparatus comprisinga plurality of optical inputs to which optical signals of a predetermined one of a plurality of optical channels are intended to be supplied, a plurality of optical outputs to which optical signals of said predetermined optical channel are intended to be supplied, an optical switch matrix having a plurality of optical switching states including at least â€œkeep-aliveâ€  and â€œprotection accessâ€  states, said optical switch matrix being responsive to switch control signals to effect one of the switching states by interconnecting predetermined one of the optical inputs with predetermined ones of the optical outputs, and an optical power monitor having a number of inputs to which a portion of respective ones of the optical input signals are supplied, wherein said optical power monitor declares a loss of signal if one of said ones of the optical input signals meets predetermined criteria, said loss of signal initiating generation of said switch control signals.