Integrated Photonic Circuit for Generation and Isolation of Single Photons from Quantum Dot Ensembles

Practical quantum photonic technology must be scalable, highly isolated from noise, low loss, and have high stability of optical elements. These needs have motivated the development of photonic integrated circuits (PICs) for quantum optical devices. While significant progress has been made in silicon PICs, generating single photons depends on heralded, probabilistic processes such as spontaneous down-conversion. III-V quantum dots (QDs) have demonstrated deterministic, high-purity, single-photon and entangled-pair emission, including electrically-pumped QDs, providing a path towards source integration. We have previously demonstrated tungsten silicide waveguide-integrated superconducting single-photon detectors with low dark counts (~1 count per 1000 s) on a III-V PIC with waveguide-coupled LEDs. These detectors may allow in-situ measurement of on-chip single-photon sources. We will demonstrate on-chip generation of single photons from a QD ensemble, using ring resonators to isolate the emission of single dots. These circuits may be tuned thermally, and cascaded ring resonators may have sufficiently high Q-factors to isolate single transitions. On-chip detectors may be used to quantify single-photon purity using an integrated Hanbury-Brown and Twiss interferometer.