Patent ID: 6351581
Filing Date: 2002-02-26
Classification: G02B,H04J

Abstract:
An optical add-drop multiplexer (ADM) comprising:a first optical coupler having at least one input port and two output ports, said coupler being arranged to distribute equal amounts of lightwave signals at the input port(s) to the two output ports; first and second optical demultiplexers, each having an input port and a plurality of output ports, the input port of each demultiplexer being connected to a different one of the output ports of the first optical coupler; first and second optical multiplexers, each having a plurality of input ports that are connected to corresponding output ports of the demultiplexers by coherent connecting paths, wherein at least one of the coherent connecting paths includes an element for increasing or decreasing its optical length, and wherein the first and second optical multiplexers each have an output port that is connected to a second optical coupler.