Second-harmonic generation from a first-order quasi-phase-matched GaAs/AlGaAs waveguide crystal

Abstract

We demonstrate, for the first time to our knowledge, the generation of second-harmonic pulses by use of a novel methodology for achieving first-order quasi-phase matching in a semiconductor waveguide crystal. This methodology is based on a periodic modulation of the susceptibility coefficient along the direction of light-beam propagation in which advantage is taken of the fact that χGaAs2>χAlxGa1-xAs2. Efficient second-harmonic generation at 975 nm of a pump wavelength of 1950 nm has been demonstrated for a crystal with a nonuniform domain dimension (duty cycle, ∼39/61).