All-Optical Regeneration of DQPSK/QPSK Signals Based on Phase- Sensitive Amplification

A novel scheme of all-optical regeneration for DQPSK and QPSK signals using phase-sensitive amplifiers (PSAs) is proposed and its effectiveness is studied through numerical simulations. By leveraging the ability of PSAs to provide phase and amplitude regenerative amplification, simulation results show significant simultaneous suppression of both phase and amplitude noise of (D)QPSK signals. The reduction in the phase noise variance of a noise-corrupted DQPSK signal obtained by one such regenerative amplification can be as large as 10 fold over a relatively large OSNR range, showing its good potential in distributed optical regeneration of a (D)QPSK signal.