Recent advances in phase matching of second-order nonlinearities in monolithic semiconductor waveguides

Techniques used to assist phase matching of second-order nonlinearities in semiconductor waveguides are reviewed. The salient points of each method are highlighted, with their strengths and weaknesses with regard to various key applications discussed. Recent progress in these techniques is also reviewed. Emphasis is placed on two techniques, namely quasi-phase matching via domain disordering utilizing quantum well intermixing, and exact phase matching using Bragg reflection waveguides. The figure shows (a) An optical microscope image of an ion implantation mask used to fabricate gratings used for quasiphase matching, (b) a scanning electron micrograph of an ion implantation mask, (c) a scanning electron micrograph of a semiconductor ridge waveguide structure, and (d) an optical microscope image of group monolithic ring lasers designed for integration with quasiphase matched structures.