Patent ID: 7460785

Claim:
An apparatus for performance monitoring in a communication system, the apparatus comprising: (a) an optical autocorrelator (OAC) configured to receive an optical signal from the communication system and to generate one or more samples of an autocorrelation function corresponding to the optical signal; and (b) a signal processing module (SPM) configured to characterize an impairment in the optical signal based on the one or more samples, wherein: the OAC comprises: two or more splitters configured to direct three or more copies of the optical signal via three or more optical paths, wherein the three or more optical paths are characterized by two or more relative time delays; and one or more OAC detectors configured to generate electrical signals based on a superposition and mixing of signal copies, wherein the samples are based on said electrical signals; the SPM comprises a discrete Fourier transform (DFT) element configured to generate one or more spectral components based on the one or more samples; and the SPM is configured to characterize the impairment based on the one or more spectral components.