Nonlinear switching in an all-semiconductor-optical-amplifier loop device

An all-semiconductor-optical-amplifier loop device with a multimode interference (MMI) coupler was fabricated with the deep UV cryo-etching technique. Efficient power-dependent switching was observed. With continuous-wave signals, nonlinear switching occurred due to the combined effect of the nonlinear coupling in the MMI coupler and the lateral wave field redistribution caused by the loop structure. Simulation results showed good agreement in trend with the experimental data.