Efficient second-harmonic generation in birefringently phase-matched GaAs/Al(2)O(3) waveguides

Opt Lett. 2001 Nov 15;26(22):1785-7. doi: 10.1364/ol.26.001785.

Abstract

We report efficient second-harmonic generation of femtosecond pulses in birefringently phase-matched GaAs/Al(2)O(3) waveguides pumped at 2.01mum. By use of pump pulses of ~200-fs duration and type I interaction, practical second-harmonic average powers of up to ~650muW were obtained, with an average input power of ~50muW. Waveguides of four different widths and two different lengths were investigated, and a normalized conversion efficiency of greater than 1000%W(-1)cm(-2) 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.