QPSK Signal Regeneration Based on Vector Phase Sensitive Amplification With Low Pump Powers

In this paper, an all-optical quadrature phase shift keying (QPSK) phase regeneration scheme using vector phase sensitive amplification (PSA) is proposed, analyzed, and simulated. Compared with the conventional scalar PSA scheme, the vector superposition of harmonics makes it easy to obtain high gain extinction ratio (GER) with low pump powers. A subsequent phase-preserving amplitude regenerating device is also introduced to achieve full-quadrature regeneration of signal without phase conjugation and frequency conversion. In addition to the theoretical analysis of the implementation principle, a series of simulation results' analysis, including comparison with traditional scheme and regeneration performance assessment, is also included. The results show that undesired harmonics are greatly reduced by nearly 40 dB, and high GERs are available independent of input power. What is more, various levels of phase and amplitude noise can be effectively compressed for 10-Gbd QPSK signal. The regeneration system also reduces the signal bit error rate and gets 2-dB receiver optical signal noise ratio (OSNR) improvements at 13-dB OSNR input, which has potential applications in enhancing transmission distance in the future optical communication network.