Patent ID: 8554081

Claim:
A wavelength division multiplexed (WDM) optical system comprising: a trunk terminal configured to provide a WDM trunk signal on a trunk path, said trunk signal comprising trunk signal utilized channels and trunk signal unutilized channels; a branch terminal configured to provide a WDM branch signal on a branch path, said branch signal comprising branch signal utilized channels and branch signal unutilized channels, at least one of said branch signal utilized channels corresponding to a wavelength of at least one of said trunk signal unutilized channels, and at least one of said trunk signal utilized channels corresponding to a wavelength of at least one of said branch signal unutilized channels; an optical add/drop multiplexer (OADM) coupled to said trunk path and said branch path for receiving said trunk signal and said branch signal and providing an output signal, said OADM comprising a first coupler configured to receive said trunk signal, said first coupler having a first output for dropping one or more of said trunk signal utilized channels and a second output comprising said trunk signal and a command signal, said OADM being configured to separate said command signal from said trunk signal; at least one band-pass filter configured to receive at least one of said branch signal or said trunk signal and to selectively remove at least one band of channels from said one of said branch signal or said trunk signal in response to said command signal to provide a band pass filtered signal, said band of channels comprising a plurality of said branch signal utilized channels, a plurality of said branch signal unutilized channels, a plurality of said trunk signal utilized channels, or a plurality of said trunk signal unutilized channels; and at least one output coupler coupled to said at least one band-pass filter and configured to receive said band pass filtered signal and provide a WDM output signal comprising said at least one trunk signal utilized channel, said at least one branch signal utilized channel, and loading signals on all unutilized channels of said WDM output signal.