Modelling All-Optical Switching and Limiting Properties of AlAs Photonic Crystals

The incorporation of defect modes into the perfect crystal structure allows the control of the flow of light by altering the photonic bandgap and thereby can be manipulated to achieve optical switching. A model for all optical switching and limiting based on two dimensional photonic crystals is proposed for AlAs and the performance in square and hexagonal lattice structures were evaluated. Simulations were done using 2D finite difference time domain model incorporating instantaneous Kerr’s nonlinearity. The optimal nonlinear resonant frequencies and the refractive index change required for the performance in the nonlinear regime were obtained. The limiter effectiveness is analysed using extinction ratio. The lattice constant and the optimal microcavity distance required for the proposed model to work as a switch and a limiter in the telecommunication wavelength of 1.55 µm were obtained asand 2a respectively.