Waveform restoration in semiconductor optical amplifier using fiber loop mirror

In this letter, we present a simple and effective interferometric approach for waveform restoration in a semiconductor optical amplifier (SOA) using a fiber loop mirror. Pattern-dependent distortion caused by gain dynamics of the SOA can be compensated. With our scheme, an enhanced input power dynamic range of 7 dB was achieved. For data sequences with different pattern lengths, both significant waveform and extinction ratio improvement were obtained.