All-optical switching using AlGaAs waveguide devices at 1.55 μm

The author has considered all-optical switching using semiconductor waveguides, in the half band gap spectral region. At this detuning, there is an enhancement in the nonlinear refractive index, while the detrimental effects of two-photon absorption are minimised. The result is an almost ideal Kerr like nonlinearity, which has proved useful for demonstrating a range of nonlinear effects. The nonlinear directional coupler, de-multiplexing and the nonlinear Mach-Zehnder interferometer have been considered. In addition, half band gap nonlinearities have been used to observe all-optical switching in nonlinear X-junctions, mode-lock colour centre lasers and as a material for the study of spatial solitons. The material is thus ideal for the study and implementation of a range of novel nonlinear effects