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A design study is presented for difference-frequency generation (DFG) in aluminum gallium arsenide (AlGaAs)- on-insulator waveguides. AlGaAs is a mature technology platform with large optical nonlinearities, a high refractive index contrast, and the presence of second-order susceptibility, making it interesting for chip-based frequency conversion. This work targets to efficiently down-convert single-photons to the telecom C-band by DFG. Modal phase-matching (PhM) is used, where the waveguide dimensions are optimized for an efficient and robust conversion of single-photons at 930 nm to around 1550 nm. This paves the way for a single-photon converter that can be integrated on a chip-platform with a single-photon emitters, along other photonic components with standard fabrication techniques. Furthermore, a thorough revision of the DFG theory provides insight into the particular case of a low-powered pump, which is relevant for quantum applications. Finally, a comparison is made with state of the art devices in periodically poled thin film lithium niobate (PPLN). This is, to the best of our knowledge, the first design of a single-photon converter operating in the telecom band that is realized with a III-V material.

We design and experimentally characterize a novel microwave (MW) photonics ring modulator based on waveguide-resonator coupling modulation. The experiments reveal that at MW frequencies corresponding to the FSR of the ring or integer multiples thereof, the resonant device generates 10 to 19 times higher MW output power than the equivalent standard Mach-Zehnder modulator, thus showing our resonant modulator paves the way for energy-efficient and low driving MW power operation. Moreover, as this resonant enhancement occursover a bandwidth of 2 to 3 GHz, our modulator has the potential to be implemented as a key element in the upcoming microwave and millimeter wave bands of 5G networks. Finally, the device solely consists of standardbuilding blocks provided by the multi-project wafer run of the SMART Photonics foundry, thus showing it can be fabricated in a relatively mature photonics integration process.