Multichannel All-Optical RZ-PSK Amplitude Regeneration Based on the XPM Effect in a Single SOA

We propose and demonstrate simultaneous amplitude regeneration for return-to-zero phase shift keying (RZ-PSK) signals. Parallel 6 × 40 Gb/s operation can be achieved using the cross-phase modulation effect in a single saturated semiconductor optical amplifier and subsequent narrow filtering. The spectrum of the distorted signal can be broadened due to the phase modulation induced by the synchronous optical clock signal. A narrow bandpass filter is utilized to extract part of the broadened spectrum and remove the amplitude noise, while preserving the phase information. Numerical simulation and experimental demonstration show that the proposed scheme can work well for RZ-PSK signals with amplitude noise. The bit error ratio measurements show that an average -1.3 dB power penalty can be achieved for all the channels. Furthermore, the tolerance of the amplitude regeneration is investigated.