Third-harmonic Generation in AlGaAs Photonic Crystal Waveguides

Two-dimensional photonic crystals are artificial periodic structures that can be made of a 2-D array of cylindrical nanoholes. Thanks to their unusual dispersion characteristics, photonic crystals may exhibit some peculiar optical properties such as extremely low group velocity. Photonic crystal waveguides can be created by removing a row of holes in a 2-D photonic crystal. In this work, we theoretically demonstrate third-harmonic generation in an air-bridge PhC waveguide based on a highly nonlinear material Al0.18Ga0.82As by exciting a slow-light mode at 1596 nm to match the refractive index of a folded-back refractive index mode at 532 nm.