Aluminium gallium arsenide (AlGaAs) is a promising material to realise nonlinear optical frequency conversions and photon-pair generations due to its high nonlinear optical susceptibilities. Its versatile bandgap and direct bandgap through adjustment of its alloy composition can potentially lead to a potent monolithic electrically-injected photon-pair source. In this dissertation, we will be focusing on developing the AlGaAs-on-insulator (AOI) photonic platform for nonlinear optical frequency conversions and photon-pair generations. We develop the process flow to bond commercially available AlGaAs substrates on silicon carriers. We develop dedicated etching processes to pattern our devices on AOI chips of different aluminium contents. We demonstrate loaded Q’s in the range of ~10⁴ in...[ Read more ]

Aluminium gallium arsenide (AlGaAs) is a promising material to realise nonlinear optical frequency conversions and photon-pair generations due to its high nonlinear optical susceptibilities. Its versatile bandgap and direct bandgap through adjustment of its alloy composition can potentially lead to a potent monolithic electrically-injected photon-pair source. In this dissertation, we will be focusing on developing the AlGaAs-on-insulator (AOI) photonic platform for nonlinear optical frequency conversions and photon-pair generations. We develop the process flow to bond commercially available AlGaAs substrates on silicon carriers. We develop dedicated etching processes to pattern our devices on AOI chips of different aluminium contents. We demonstrate loaded Q’s in the range of ~10⁴ in the microring resonators and ~10⁵ in the microdisc resonators at the ~1550 nm telecommunication wavelengths. We also demonstrated loaded Q’s in the range of ~10⁵ in the microring resonators at the ~775 nm near-visible wavelengths. We design and demonstrate type-I second-harmonic generation (SHG) process in our AOI waveguides. We experimentally observe cavity resonance-enhanced SHG in our microring and microdisc resonators. Specifically, we observe SHG in the high-order whispering-gallery modes of circular microdisc resonators. We also demonstrate sum-frequency generation (SFG) in our waveguides and microresonators. We made significant progress towards photon-pair generations. We experimentally demonstrate generation of photon-pairs using cavity resonance-enhanced spontaneous fourwave mixing process. Our photon-pair sources achieve a spectral brightness of up to ~1.12 ± 0.20 pairs s⁻¹ mW⁻² GHz⁻¹.