Exploring Optical Nonlinearities in III-V Semiconductors

Abstract

This Master’s dissertation focuses on exploring optical nonlinearities in IIIV semiconductors. This work covers a range of III-V materials and a few devices. To begin with, optical characterization of Aluminium Gallium Arsenide (AlGaAs) waveguides with enhanced nonlinear optical interactions was carried out. We have experimentally demonstrated wide conversion ranges andhigh conversion efficiencies for four-wavemixing inAlGaAswaveguides with three different geometries. In addition to that, both linear and nonlinear losses in each of these geometries were explored. AlGaAs represents only one compound of the large group of III-V semiconductors. To explore the potentials of other semiconductors compounds of this group for nonlinear optics, it is imperative to have information about refractive indices of different III-V compounds. This refractive index information is only available for some binary compounds in isolated spectral windows. In this thesis, we developed a model capable of predicting the values of the refractive indices of binary, ternary and quaternary III-V semiconductor compounds from the values of their band-gap energies. We compared the value predicted by our proposed model with existing experimental data and it was found not only is the predicted values in good agreement with the known values, but also has a lower error margin when compared to previously reported models. Finally, in quest for more suitable material platform for nonlinear photonic integration at different wavelength ranges, a detailed analysis of other potential III-V compounds not previously explored for photonic integration is presented.