Filtering Effects Characterization in Metro-Access Networks and Future High-Speed Coherent Optical Communication Schemes

We present a detailed experimental analysis of the penalty introduced by optical filtering during propagation of a high-speed coherently detected signal. We investigate the performance penalty in terms of sensitivity reduction of a commercial coherent transceiver at a given bit error rate (BER) threshold, and resulting maximum achievable optical power budget, when transmitting a 400G PM-16QAM signal through an optical filter with variable parameters such as bandwidth, order and central frequency de-tuning. Moreover, we discuss an analytical method able to predict the experimental results with remarkable accuracy, even at variable optical signal to noise ratio (OSNR) levels and considerably low received optical power. Our analysis aims at improving our understanding of the impact of optical filtering on modern coherent communication schemes and, in particular, in the scenario of adoption of coherent detection in the short-reach transmission segment, for instance in future all-optical metro-access networks. Moreover, our analytical tool can be of great help in the design process of novel network configurations, thanks to its simplicity, reliability and speed.