Ultrafast all-optical switching induced by nonlinear polarization rotation in a multi-quamtum well semiconductor optical amplifier

We investigate the ultrafast refractive index dynamics in a multi-quantum well semiconductor optical amplifier (SOA) with a focus on nonlinear polarization switching. A pumpprobe technique is utilized to examine ultrafast carrier dynamics of the SOA in conjunction with nonlinear birefringence. Nonlinear optical effects such as two-photon absorption describe the pump-induced birefringence on the sub-picosecond time scales which introduce a significant temporal window for ultrafast applications of nonlinear polarization switching