Single- and Dual-Channel DPSK Signal Amplitude Regeneration Based on a Single Semiconductor Optical Amplifier

We experimentally demonstrate that, based on operational condition optimization, a common quantum well (QW) semiconductor optical amplifier (SOA) has the ability of amplitude regeneration for return-to-zero (RZ) differential phase shift keying (DPSK) signals. For a single-channel RZ-DPSK regeneration scheme, a significant eye-opening enhancement and a negative power penalty of about 1.0 dB are obtained. For dual-channel RZ-DPSK regeneration, it can also be found that the eye-opening improvement and power penalty decrease in each channel. In addition, the DPSK regeneration scheme based on a single QW SOA is quite simple and stable.