Analysis of optical phase conjugation using four-wave mixing in a dispersion-shifted fibre

An analysis of optical phase conjugation using four-wave mixing in a dispersion-shifted fibre is presented. Crosstalk that influences the optical phase-conjugated output signal and stems from nonphase conjugated four-wave mixing is identified for the first time. The impact of conversion fibre length, pump power and input signal power on conversion efficiency, frequency chirp, and crosstalk are given. The analysis shows that a good optical phase conjugation in terms of enhancing conversion efficiency, minimising chirp and crosstalk is obtained by the use of a pump power as high as possible, a conversion fibre length of 20 km and an input signal power of below –5 dBm.