SOA-based regenerative amplification of phase-noise-degraded DPSK signals: dynamic analysis and demonstration

A theoretical analysis and an experimental demonstration of semiconductor optical amplifier (SOA)-based regenerative amplification (SORA) of phase noise (PN)-degraded return-to-zero (RZ) differential phase-shift keying (DPSK) signals are presented. The Q-factor improvement is 1.6 dB in single-channel and about 0.8 dB in two non-demultiplexed-channel regimes. The key physical mechanism that enables regeneration by the SORA is the discriminative gain provided by the SOA for the logical 0s versus the logical 1s when two mutually antisymmetric ON-OFF keying (OOK) data trains, created by the DPSK signal, collide in the SOA. The modeling results agree with the experiment.