Ultrafast dynamics in semiconductor optical amplifiers with implications for interferometric switching

Recently there has been considerable progress in the development of optical signal processing devices employing nonlinearities in semiconductor optical amplifiers (SOAs). In particular, interferometric switching has been demonstrated. However, due to ultrafast carrier dynamics, the operation of SOA-based switches becomes increasingly complex with ultrashort pulses and at high bit rates and requires further investigation. We present experimental results from co- and counter-propagating pump-probe experiments, in strain compensated InGaAs quantum well SOAs, at 1550 nm. These reveal the very different nature of the dynamics of the opening and closing of the switching window. Time-resolved spectra of the output pulses were also monitored to determine spectral shifts.