Patent ID: 6922530
Filing Date: 2005-07-26
Classification: H04J,H04Q

Abstract:
1. An apparatus, comprising a multiplexing unit which includes: an optical input terminal to which can be applied an optical input signal that includes a plurality of optical component signals which are different; an optical output terminal at which said multiplexing unit produces an optical output signal; a plurality of protection input terminals; a plurality of protection output terminals; a demultiplexer having an input coupled to said optical input terminal, and having a plurality of outputs, said demultiplexer being operable to optically isolate the component signals of the input signal, and to optically supply each of the isolated component signals to a respective one of said outputs thereof; a plurality of switching units each having first and second inputs and first and second outputs, each said switching unit being capable of optically coupling said first output thereof to a selected one of said first and second inputs thereof, and being capable of optically coupling said second output thereof to a selected one of said first and second inputs thereof, wherein said outputs of said demultiplexer are each coupled to said first input of a respective said switching unit, said protection input terminals are each coupled to said second input of a respective said switching unit, and said protection output terminals are each coupled to said second output of a respective said switching unit; a multiplexer having an output coupled to said optical output terminal, and having a plurality of inputs which are each coupled to said first output of a respective said switching unit, said multiplexer being operable to optically multiplex onto said output respective optical component signals present at each of said inputs thereof; an optical drop coupler coupled between said optical input terminal and said demultiplexer, said optical drop coupler being operable to forward a first copy of said input signal to said demultiplexer and to drop a second copy of said input signal; and one or more drop terminals each operable to receive a respective one of said optical component signals included in said second copy of said optical signal dropped by said optical drop coupler.