Device length dependence of optical second-harmonic generation in AlGaAs quasiphase matched waveguides

Device length dependence of optical second-harmonic generation (SHG) in AlGaAs semiconductor quasiphase matched (QPM) waveguides with periodically crystal domain inverted gratings has been studied both experimentally and theoretically. It is found that the SHG power depends strongly on device length. An optimum device length for obtaining maximum SHG is shown for QPM-SHG devices with non-negligible waveguide propagation loss. It is also shown that this optimum device length can be predicted theoretically, making experimental optimization unnecessary.