Method of compensating cross phase modulation in 10Gbit/s WDM systems over nonzero dispersion shifted fibre

Introduction: The use of wavelength division multiplexing (WDM) and optical amplification as a method of increasing the information capacity and/or reach in optical fibre systems has led to significant propagation impairments owing to fibre nonlinearity [1]. Important nonlinear effects causing inter-channel crosstalk in WDM systems are four wave mixing (FWM) and cross phase modulation (XPM). FWM can be managed by increasing the system dispersion or by using unequal channel spacing [2]. Neither of these approaches, however, decreases the system impairment due to XPM [3 – 5]. We demonstrate a novel technique which can compensate for XPM by prechirping the signal channel with a filtered version of an interfering WDM channel at the transmitter.