Patent ID: 7634196

Claim:
A reconfigurable WDM add/drop multiplexer operative as an add/drop node on an optical fiber carrying a plurality of WDM signals, said add/drop multiplexer comprising: a coupler splitting said WDM signals on said optical fiber, said coupler having an input terminal for connection to said optical fiber, and first and second output terminals for said split WDM signals from said optical fiber; a demultiplexer element connected to said first coupler output terminal, said demultiplexer separating said split WDM signals at a plurality of drop terminals; and a wavelength-selective switch having a demultiplexer element having a plurality of output terminals and an input terminal for connection to said second coupler output terminal a multiplexer having a plurality of input terminals and an output terminal for connection to said optical fiber, and a plurality of 2×1 switches, each connected to one of said demultiplexer output terminals, one of said multiplexer input terminals and one of a plurality of add terminals, each switch either connecting said multiplexer input terminal to said demultiplexer output terminal or to said add terminal in response to a control signal, whereby said wavelength-selective switch selectively adds WDM signals on said plurality of add terminals responsive to control signals.