Multi-Impairment Monitoring at 320 Gb/s Based on Cross-Phase Modulation Radio-Frequency Spectrum Analyzer

We introduce a scheme for multi-impairment performance monitoring at ultrahigh bit rates based on cross-phase modulation (XPM) in a nonlinear waveguide. We demonstrate that we can simultaneously monitor in-band optical signal-to-noise ratio and group velocity dispersion at bit rates of 320 Gb/s (return-to-zero format) from a single measurement. Our approach retrieves the autocorrelation of the signal via the radio-frequency (RF) spectrum, which is captured with an XPM-based RF spectrum analyzer in a highly nonlinear fiber.