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 1.55μm . Periodic spatial modulation of the bulklike second-order susceptibility χ<sup>(2)</sup><sub>zxy</sub> was achieved with quantum-well intermixing for which the group III vacancies were created by As<sup>+</sup> -ion implantation. A narrow second-harmonic bandwidth of ~0.9nm (FWHM) with an average power of ~1.5μW was detected, corresponding to an internal conversion efficiency of ~0.06%, which was considerably limited by the spectral bandwidth of the fundamental.
© 2003 Optical Society of America
(160.4330) Materials : Nonlinear optical materials
(190.2620) Nonlinear optics : Harmonic generation and mixing
(190.5970) Nonlinear optics : Semiconductor nonlinear optics including MQW
(230.7370) Optical devices : Waveguides
K. Zeaiter, D. C. Hutchings, R. M. Gwilliam, K. Moutzouris, S. Venugopal Rao, and M. Ebrahimzadeh, "Quasi-phase-matched second-harmonic generation in a GaAs AlAs superlattice waveguide by ion-implantation-induced intermixing," Opt. Lett. 28, 911-913 (2003)