Calculation of quasi phasematching in optical parametric GaAs/AlGaAs waveguides

摘要

Quasi phasematched domain periods for bulk and waveguide GaAs nonlinear frequency conversion were calculated. Waveguide beam confinement resulted in a decrease in effective refractive index and the magnitude of this index change was found to increase supralinearly with wavelength. Domain periodicity required for a 2.056-μm pumped, 10×10 μm~2 GaAs core, Al_(0.5)Ga_(0.5)As cladding waveguide OPO at degeneracy decreased from 60.4 μm for bulk GaAs to 57.9 μm for a rib waveguide and 49.8 μm for a buried waveguide in a GaAs OPO. Careful accounting for waveguide effects is necessary to fabricate a periodic waveguide structure with the desired function.