Photonic chip-based simultaneous multi-impairment monitoring for phase-modulated optical signals

We report the first experimental demonstration of simultaneous multi-impairment monitoring of phase-modulated 40 Gbit/s nonreturn to zero differential phase-shift keying (NRZ-DPSK) and 640 Gbit/s return-to-zero (RZ)-DPSK optical signals. Our approach exploits the femtosecond response time of the Kerr nonlinearity in a centimeter-scale, highly nonlinear, dispersion engineered chalcogenide planar waveguide to perform THz bandwidth RF spectrum analysis. The features observed on the radio-frequency (RF) spectrum are directly utilized to perform simultaneous group velocity dispersion and in-band optical signal-to-noise ratio (SNR) monitoring. We also numerically investigate the measurement accuracy of this monitoring technique, highlighting the advantages, and suitability of the chalcogenide rib waveguide.