Electrical compensation of FWM impairment by phase diversity detection via backward propagation

Nonlinear effects induced by Kerr effect in optical fibers result in the severe inter-channel crosstalk and degrade WDM transmission system performances. The electrical post-compensation through backward propagation is demonstrated for nonlinear impairment compensation of FWM via phase diversity detection, whose required bandwidth is less than that of heterodyne detection. By 20-km transmission of dispersion-shifted fiber (DSF), the generated FWM components with both of the original optical signals whose wavelength are around 1550nm are detected by phase diversity detection with one local oscillator. The detected signals are compensated by off-line signal processing using backward propagation, and after compensation there is over 6dB improved for the power difference between signals and FWMs.