Polarization Mode Dispersion Insensitive and Nonlinear Polarization Scattering Robust Optical Signal-to-Noise-Ratio Monitoring Technique

We propose an in-band optical signal-to-noise-ratio (OSNR) monitoring technique. The technique uses the polarization characteristics of two narrow bandwidth filtered optical spectral components. It can almost completely eliminate the effects of polarization mode dispersion (PMD) and is also robust to inter-channel cross- phase modulation (XPM) induced nonlinear polarization scattering. The mechanism of its robustness to the polarization effects is explained, and the monitoring technique is demonstrated experimentally in both linear and nonlinear systems. Like degree of polarization (DOP) based OSNR monitoring techniques, this technique is also independent of bit rates and modulation formats.