Experimental study of SPM and XPM using real time coherent DSP for ROADM systems

The distortion of coherent signals caused by nonlinear effects were studied experimentally using a real time DSP at 40 Gbps. It was shown that coherent signals were primarily degraded by SPM in the case of a 50 GHz ROADM grid. The XPM-induced penalty increased on reducing the channel spacing to 25 GHz.