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.
