An optical performance monitor (OPM) adapted to (i) sample an autocorrelation function corresponding to an optical signal transmitted in an optical network and (ii) based on the sampling, characterize two or more impairments concurrently present in the optical signal. In one embodiment, the OPM has an optical autocorrelator (OAC) coupled to a signal processor (SP). The OAC receives the optical signal from the network, generates two or more samples of its autocorrelation function, and applies said samples to the SP. The SP processes the samples and generates two or more signal metrics. Based on the signal metrics and reference data corresponding to the impairments, the SP then obtains a measure of each of the impairments.