A High Efficiency Scheme for Phase-Matched Second-Harmonic Generation in GaN-Based Bragg Reflection Waveguide

We present an analysis of a high index core symmetric Bragg reflection waveguide (BRW) design based on GaN-Al_xGa_1-xN system for efficient phase-matched second-harmonic generation (SHG). Using phase-matched interaction between a zeroth-order total internal reflection guided mode at fundamental and a BRW mode at second harmonic, an enhancement in efficiency is brought about by suitably inverting the domains in the core of BRW. The design allows us to obtain a suitable poling thickness using a simple relation and the thickness calculated for poling in GaN core is feasible to be realized experimentally. The tolerance of the SHG process towards wavelength fluctuations is also analyzed.