We report efficient second-harmonic generation of femtosecond pulses in birefringently phase-matched GaAs/Al<sub>2</sub>O<sub>3</sub> waveguides pumped at 2.01μm. By use of pump pulses of ~200-fs duration and type I interaction, practical second-harmonic average powers of up to ~650μW were obtained, with an average input power of ~50μW. Waveguides of four different widths and two different lengths were investigated, and a normalized conversion efficiency of greater than 1000%W<sup>-1</sup>cm<sup>-2</sup> was obtained for a 1-mm waveguide. Measurements of pump and second-harmonic spectra provided clear evidence of phase matching and depletion of the pump spectrum. The measured bandwidth of the second harmonic was ~1.3nm. From the measurements of transmitted pump power at the phase-matching wavelength, pump depletions of more than 80% were recorded.
© 2001 Optical Society of America
(160.4330) Materials : Nonlinear optical materials
(190.2620) Nonlinear optics : Harmonic generation and mixing
(190.5970) Nonlinear optics : Semiconductor nonlinear optics including MQW
(230.7370) Optical devices : Waveguides
K. Moutzouris, S. Venugopal Rao, M. Ebrahimzadeh, A. De Rossi, V. Berger, M. Calligaro, and V. Ortiz, "Efficient second-harmonic generation in birefringently phase-matched GaAs/Al2O3 waveguides," Opt. Lett. 26, 1785-1787 (2001)