Waveguide nanowire superconducting single-photon detectors fabricated on GaAs and the study of their optical properties

Quantum photonic integration is one of the leading approaches for enabling the implementation of quantum simulation and computing at the scale of tens to hundreds of photons. Quantum photonic integrated circuits require the monolithic integration of single-photon sources and passive circuit elements, such as waveguides and couplers, with single-photon detectors. A promising approach for on-chip single-photon detection is the use of superconducting nanowires on top of semiconductor waveguides. Here, we present state-of-the-art NbN films on GaAs for the realization of waveguide superconducting single-photon detectors, suitable for integration with sources and linear optical circuits. Based on the measured optical properties, we propose a new design which allows high absorptance for short nanowires in order to increase the integration density in a quantum photonic chip. Finally, we review recent results on integrated single-photon and photon-number-resolving detectors, and integrated autocorrelators.