ABSTRACT
One of the key transmission performance indicators for coherent optical transponder is the Bit Error Rate (BER) versus Optical Signal to Noise Ratio (OSNR) characteristics. We have developed a model to predict BER versus OSNR at various Receiver Optical Power (ROP). The model has three parameters, which are related to BER noise floor, filter mismatching, and OSNR value without noise loading. The model is applied to transponders with high baud rate and Quadrature Amplitude Modulation (QAM). By considering the influence of baud rate on the fitting parameters, accurate prediction of performance for coherent transponder can be achieved over various baud rates. Novel applications enabled by this model include in-field measurement of BER versus OSNR, simple abstraction of coherent transponder, accurate OSNR monitor and coherent optical channel monitor.
