Numerical simulation on pulsed operation of an all-semiconductor optical amplifier nonlinear loop device

Pulsed-signal self- and cross-switching operations in an all-semiconductor-optical-amplifier (SOA) nonlinear optical loop device are numerically investigated. The device consists of a loop amplifier, a multimode-interference waveguide amplifier (MMIWA), an input leg, and an output leg. With the combined mechanisms, including nonlinear coupling in the MMIWA, lateral field redistribution and amplification by the loop, and asymmetric gain-phase modulation between two counterpropagating signals in the loop, the device operates with efficient power-dependent switching. Simulations were conducted using a modified time-domain traveling-wave method for the interplay between the two counterpropagating signals in MMIWA and loop. Typical parameter values of GaAs-AlGaAs multiple quantum-well (MQW) optical amplifiers were adopted for simulating separately published experimental conditions. Numerical results of simulation agreed well in physical trend with the reported experimental data.