Photonic crystal all-optical switch based on a nonlinear cavity

We demonstrate high-speed all-optical switch structure using an ultra-small nonlinear cavity coupled to input and output waveguide. The whole structure is based on a square lattice photonic crystal formed by rods of refractive index nr = 3.4 in an air background. Finite-difference time-domain method is used to analyze the device characteristics. By analyzing of behavior of structure, we show that switching from OFF to ON occurred because resonant wavelength shift is caused by Kerr effect. The simulation result shows that switch has a high-speed response of ∼26 ps. Since the structure has an ultra-small length of 12 μm, it has a potential to use in integrated optical-circuits.