QUASIPHASE MATCHED SURFACE-EMITTING 2ND-HARMONIC GENERATION IN PERIODICALLY REVERSED ASYMMETRIC GAAS ALGAAS QUANTUM-WELL WAVE-GUIDE/

We experimentally demonstrate surface-emitting second harmonic generat ion in a waveguide containing asymmetric coupled GaAs/AlGaAs quantum w ells. The nonlinear conversion efficiency is enhanced by reversing the asymmetric well orientation every coherence length, in order to quasi phase match the vertical second harmonic generation process. The measu red spectrum of the asymmetric quantum well susceptibility is dominate d by an excitonic peak at a pump frequency corresponding to half of th e first electron-heavy hole transition energy. (C) 1997 American Insti tute of Physics.