III-V photonic integrated circuit with waveguide-coupled light-emitting diodes and WSi superconducting single-photon detectors.

We demonstrate cryogenic, all on-chip, single-photon-level photonic integrated circuits on a III-V platform with waveguide-coupled quantum-well sources and tungsten silicide superconducting nanowire single-photon detectors. We have measured the dark count rates below 10⁻³ counts/s and have reduced the cross talk to an adjacent waveguide by 30 dB. [ABSTRACT FROM AUTHOR]