Phase dynamics in semiconductor optical amplifiers for all-optical switching

We present an experimental and numerical investigation on phase dynamics in semiconductor optical amplifiers (SOAs). The experiment for measuring the phase recovery is carried out using an integrated SOA-based Mach-Zehnder interferometer switch, under the injection of 2 ps optical pump pulses at 10 GHz. The phase recovery is derived from the measured output of the interferometer. Ultrafast component in the phase recovery is observed, and a delay between phase and gain recovery is also found. The impact of the different carrier dynamics on phase and gain recovery is analyzed by using a field propagation numerical model. The results are important for SOA-based ultrafast optical signal processing.