title: Broadening of the phase-matching bandwidth in quasi-phase-matched second-harmonic generation using GaN-based Bragg reflection waveguide.
abstract: We present an analysis of a high index core symmetric Bragg reflection waveguide (BRW) design based on a GaN/AlxGa1-xN system for efficient quasi-phase-matched second-harmonic generation for broadband applications. By choosing the fundamental frequency to be a BRW mode and suitably tailoring the overall dispersion characteristics, the strong dispersion of the second-harmonic mode is partially canceled, leading to phase matching between the fundamental and second-harmonic over a broad range of wavelengths. The crucial interplay between the dispersive behavior of the fundamental and second-harmonic wave manifests as a broad acceptance bandwidth of approximately 33 nm accompanied with appreciable conversion efficiency (22.8%/W) for a 10 mm long waveguide. The impact of tailoring the dispersion characteristics on the conversion efficiency is also discussed.
authors.affiliation: Department of Physics, Indian Institute of Technology, Hauz Khas, New Delhi, India. ritwick.das@gmail.com
authors.forename: Ritwick
authors.initials: R
authors.lastname: Das
authors.forename: K
authors.initials: K
authors.lastname: Thyagarajan