All-optical in-band OSNR monitors based on unphase-matched four-wave mixing

Abstract

This paper presents a novel all-optical in-band optical signal-to-noise (OSNR) monitor. The monitoring ability arises from the power transfer function (PTF) provided by un-phase-matched four-wave mixing (FWM). A much higher output contrast compared to formal methods can be obtained at a much lower required power. Numerical simulations are then used to quantify the sensitivity enhancement for signals with different modulation formats which show that the monitoring sensitivity can be greatly improved by more than 10 dB for NRZ, CSRZ, RZ modulation formats while the required power can be reduced by about 3 dB.