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

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 chi ((2))(GaAs) > chi ((2))(AlxGa1-xAs). Efficient second-harmonic generation at 975 mn of a pump wavelength of 1950 nm has been demonstrated for a crystal with a nonuniform domain dimension (duty cycle, similar to 39/61). (C) 2001 Optical Society of America.