An all-optical regeneration scheme for DQPSK and QPSK signals using phase-sensitive amplifiers (PSAs) is studied and its effectiveness

is investigated through numerical simulations. By leveraging the ability of PSAs to provide phase and amplitude regenerative amplification,

we show significant simultaneous suppression of both phase and amplitude noises of (D)QPSK signals under optimized

conditions. The reduction in the phase noise variance of a noise-corrupted DQPSK signal obtained by one such regenerative amplification

can be as large as 5.5 folds, showing its good potential for distributed optical regeneration of (D)QPSK signals.

 2008 Elsevier B.V. All rights reserved.