Quasi-phase matched second-harmonic generation in an AlxGa1−xAs asymmetric quantum-well waveguide using ion-implantation-enhanced intermixing

Quasi-phase matched second-harmonic generation in the copropagating geometry is demonstrated in an asymmetric quantum-well waveguide. Modulation of the nonlinear susceptibility along the waveguide was achieved using a patterned quantum-well intermixing process. Photoluminescence measurements of the quantum-well bandedges indicate that a grating of alternating regions of intermixed and as-grown asymmetric quantum wells was produced for periods between 2 and 12 μm. The variation of the second-harmonic light intensity generated by guided incident light between λ=1480 and 1600 nm was measured. The resulting second-harmonic spectra show sharp quasi-phase matching resonances for grating periods near 3 μm, demonstrating that a periodic modulation of the quantum-well nonlinear susceptibility was produced.