WDM Signal All-Optical Precompensation of Kerr Nonlinearity in Dispersion-Managed Fibers

Compensation of the Kerr nonlinearity in dispersion-managed optical fiber links is demonstrated for 100-GHz-spaced wavelength division multiplexing (WDM) 40-Gb/s return-to-zero-differential phase-shift keying signals using all-optical nonlinear predistortion and phase-conjugation at the transmitter. Measurements of the bit-error rate (BER) reveal a Q²-factor improvement from 1.3 to 2.9 dB for transmission of one to four WDM channels in a standard single-mode fiber link. Although signal distortion is primarily from intrachannel nonlinearity, the BER is also degraded by linear and nonlinear interchannel crosstalk.