Variations of optical M-waveguides for direct phase matching in AlGaAs

Two variations of an optical indexwise M-shaped waveguide structure in AlGaAs are presented as results of numerical simulations. The principal differences of the waveguiding aspects are discussed. The impact of the optical layer thicknesses is investigated with respect to phase matching and conversion efficiency for second-harmonic generation (SHG). Despite large differences in the interacting mode distributions, both waveguide configurations yield comparable nonlinear normalized conversion efficiencies. The technologically simple waveguide designs represent an attractive alternative for phase matched SHG.