Band gap gratings using quantum well intermixing for quasi-phase-matching

In this work, the spatial resolution of two quantum well intermixing processes has been obtained using spatially resolved photoluminescence. The processes investigated are impurity-free vacancy disordering using SiO2/SiO2:P caps and sputtered silica induced intermixing. These studies aimed to choose a suitable intermixing technology to realize the band gap gratings for domain disordering quasi-phase-matching in GaAs/AlGaAs heterostructures. From the photoluminescence studies it was established that the process of impurity-free vacancy disordering using SiO2/SiO2:P caps has a spatial resolution on the order of 7 m, while the process of sputtered silica induced intermixing has a spatial resolution on the order of 3 m. From these measurements it was demonstrated that the sputtered silica induced intermixing process is more suitable for the fabrication of the gratings needed for quasi-phase-matching in the samples studied here. Successful quasi-phase-matching demonstrated through second harmonic generation at 775 nm has been produced in GaAs/AlAs short superlattice waveguides using sputtered silica induced intermixing through domain disordering quasi-phase-matching. The gratings have shown a duty cycle far from the targeted 1:1 design, which has implications on the conversion efficiency. © 2006 American Institute of Physics. DOI: 10.1063/1.2402034