Quasi-phase-matched second-harmonic generation in a GaAs/AlAs superlattice waveguide by ion-implantation-induced intermixing

We report type I second-harmonic generation by use of first-order quasi-phase matching in a GaAs/AlAs symmetric superlattice structure with femtosecond fundamental pulses at 1.55 mum. Periodic spatial modulation of the bulklike second-order susceptibility chi(zxy)((2)) was achieved with quantum-well intermixing for which the group III vacancies were created by As+-ion implantation. A narrow second-harmonic bandwidth of similar to0.9 nm (FWHM) with an average power of similar to1.5 muW was detected, corresponding to an internal conversion efficiency of similar to0.06%, which was considerably limited by the spectral bandwidth of the fundamental. (C) 2003 Optical Society of America.