Noise evolution with the phase-sensitive gain in a hybrid fiber phase-sensitive amplifier.

We investigate the noise evolution of a hybrid fiber phase-sensitive amplifier (PSA) with an erbium-doped fiber amplifier (EDFA) as a function of the phase-sensitive gain. The noise performance of the hybrid amplifier with a large overall gain of 45.6 dB is experimentally evaluated in optical and electrical domains. The experimental results are in good agreement with theory, showing that significant improvement of the overall noise figure (NF) of the hybrid amplifier occurs in a low PSA gain region. A combined NF below 3 dB has been obtained in the hybrid amplifier with a PSA gain of 9 dB, which is 1.1 dB better than a conventional EDFA with an equivalent overall gain.