Regenerative properties of a pump-modulated four-wave mixing scheme in dispersion-shifted fibers

A new scheme for all-optical signal reshaping is proposed. It is shown that proper adjustment of the operating conditions of a wavelength converter based on four-wave mixing (FWM) in dispersion-shifted fiber (DSF) results in significant extinction ratio enhancement and noise suppression of the converted signal. The key issue in the proposed idea is the application of the modulation bitstream on the input pump wave. Detailed numerical simulation shows that it is possible to achieve a wavelength-converted output with extinction ratio of 20 dB when the extinction ratio of the input signal is 10.5 dB, while at the same time, the improvement in the Q-factor is almost 6 (from 6.5 at the input, it becomes more than 12 at the output). The theoretical predictions have been experimentally confirmed by measuring the transfer function of the FWM in a 17-kmlong DSF under different operating conditions. The obtained results are in a very good agreement with those predicted theoretically.