Extending a Nonlinear SNR Estimator to Include Shaping Distribution Identification for Probabilistically Shaped 64-QAM Signals

An estimation method for the nonlinear signal-to-noise ratio (SNR) is extended to simultaneously identify the shaping distribution for rate-adaptive probabilistically shaped (PS) 64-ary quadrature amplitude modulation (QAM) constellations. An artificial neural network (ANN) is trained with the fiber nonlinearity induced amplitude noise covariance and phase noise correlation extracted from received...