Phase-Matched Second-Harmonic Generation in Thin Rectangular High-Index-Contrast AlGaAs Waveguides

We report the first observation of second-harmonic generation in thin rectangular high-index-contrast (HIC) birefringent-phase-matching (BPM) waveguides. We fabricated HIC waveguides composed of 0.103-µm-thick Al 0.5 Ga 0.5 As core layers sandwiched between 1-µm-thick oxidized Al 0.93 Ga 0.07 As cladding layers by using wet etching and wet oxidation techniques. BPM has been achieved in the 1.55 µm fundamental wavelength region in 1.7–1.86-µm-wide rib-type HIC waveguides. The guide-width dependence of the phase matching wavelength is in an agreement with numerical simulation.