Wavelength conversion by difference-frequency generation is achieved in a periodically domain reversed AlGaAs waveguide. The AlGaAs waveguide is epitaxially grown on a template substrate where a periodic crystal domain inversion is achieved using wafer bonding, selective etching, and organometallic chemical vapor deposition. Wavelength conversion experiments on a fabricated buried heterowaveguide showed a 90 nm conversion bandwidth, polarization diversified operation, and polarization independent conversion efficiency. The experimental results also showed linearity and spectral inversion, which imply transparency to signal formats including analog and frequency modulation. Simultaneous conversion of multiple input wavelengths with no measurable cross talk is also demonstrated.

Quasi-phase-matched second-harmonic generation is observed in an AlGaAs waveguide. The AlGaAs waveguide is epitaxially grown on a template substrate where a periodic crystal domain inversion is achieved using wafer bonding and organometallic chemical vapor deposition. A scanning electron micrograph of the waveguide cross section reveals a distinct propagation of the crystal domain boundaries in the epitaxial growth direction. Second-harmonic generation measurements on a fabricated rib-loaded waveguide show a clear quadratic dependence of the second-harmonic power to the input fundamental power. The peak conversion efficiency is 4.9%/W whereas the theoretical value is 124%/W for an ideal waveguide with no loss and with equal domain dimensions. A significant increase in the conversion efficiency is expected with reduced scattering losses realized by improved epitaxial growth and fabrication processes.

A technique, namely bonding by atomic rearrangement has been invented to realize high quality heteroepitaxy for lasers and optoelectronics. High performance lasers of 1.5 μm wavelength have been fabricated on GaAs substrates using this method. The laser has the same threshold current and quantum efficiency as lasers on InP substrates. No performance degradation has been observed. The transmission electron microscopic results show that the heteroepitaxy is excellent, without a single threading dislocation or stacking fault.

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