Patent ID: 7330669

Claim:
A method of signal processing, comprising: (A) converting a first optical signal into an electrical signal having an intermediate frequency and an amplitude corresponding to optical power of the first optical signal; (B) sampling the electrical signal two or more times per signaling interval to generate two or more signal samples, wherein there is a relative time delay between first and second signal samples of the two or more signal samples; (C) comparing each of the first and second signal samples with a decision threshold value to generate first and second sample-bit values; and (D) applying a logical function to the first and second sample-bit values to generate a bit sequence corresponding to the optical signal, wherein: the first optical signal has a first wavelength; step (A) comprises mixing the first optical signal with a second optical signal having a second wavelength, wherein the intermediate frequency corresponds to wavelength difference between the first and second wavelengths; and for a signaling interval corresponding to an optical “1”, the relative time delay and the wavelength difference cause at least one of the first and second signal samples to be greater than the decision threshold value.