SNR improvement of DPSK signals in a semiconductor optical regenerative amplifier

Signal-to-noise ratio improvement using a semiconductor optical regenerative amplifier (SORA) is characterized. It is demonstrated that for a noise-degraded return-to-zero differential phase-shift keying signal at 10 Gb/s the Q factor at the SORA's output is improved relative to its input for both the phase and amplitude noise cases. The Q-factor improvement is 1.6 dB in single-channel operation for the phase-noise only case and 0.55 dB for the amplified spontaneous emission noise-only case through the SORA.