Impact of cross-phase modulation on 320 Gbps WDM-PON architecture

In this paper, we proposed and demonstrated through experiment the effect of cross-phase modulation nonlinearities on a simulated WDM-PON downstream optical link. It is reported that within certain channel spacing, crosstalk induced by XPM increases rapidly, despite increases in transmission power. Thus, the dependency of XPM on different link parameters such as transmitted channel spacing, link length and interacting channel bit rate are the focus areas of our investigations. Using the pump-probe method, we use the pump channel to act as an interfering signal on the transmission channel band and by varying the interfering channel spacing from 12.5, 25, 50 and 100 GHz WDM-PON; we can observe its impact on the transmission channel. Evaluation of Eye diagram, Q penalties and BER are being performed. From the results, it can be observed that cross-phase modulation occurs in two conditions, that is during dense WDM channel spacing of below 25 GHz, as per the ITU-T G.694.1 recommendation and during superimposition of the pump signal and transmission band channel in time, for this experimentally simulated WDM-PON network architecture.