Q-Factor Improvement of Phase Noise Degraded DPSK Signals Using Asymmetric Saturated Regeneration

We demonstrate a 6.3 dB improvement in Q‐factor for RZ‐DPSK signals using a shifted filter after a highly saturated SOA working in a contra‐propagating colliding pulse scheme. We show first, both theoretically and by means of simulations, how the phase noise is transformed after demodulation. Then, we demonstrate experimentally, for the first time, that this configuration induces a spectral asymmetry in addition to self phase modulation that if associated with a shifted filter, removes significantly the noise present in both the demodulated marks and spaces. The Asymmetric Saturated Regeneration (ASR) is an enhanced version of the fiber based Mamyshev regenerator.