Patent ID: 7450863

Claim:
A receiver for an optical input signal, the receiver comprising: a delay interferometer (DI) adapted to receive the optical input signal, wherein the optical input signal is a multiplex of N modulated signals separated from each other by integer multiples of ½T d , where T d is a relative path delay of the DI and N is an integer greater than 1; a first wavelength-demultiplexing filter (WDF), wherein a first optical output of the DI is coupled to an optical input of the first WDF; a second WDF, wherein a second optical output of the DI is coupled to an optical input of the second WDF, wherein: each of the first and second WDFs has N outputs; and each WDF output is connected to an O-E converter adapted to convert an optical signal from the corresponding WDF into an electrical signal; and a plurality of differencing circuits, wherein each differencing circuit is associated with an O-E converter of the first WDF and a corresponding O-E converter of the second WDF, wherein each differencing circuit generates a difference between the electrical signals from the corresponding pair of O-E converters.