On-chip detection of non-classical light by scalable integration of single-photon detectors

TLDR

Photonic integrated circuits are a scalable platform for quantum technologies, and superconducting nanowire single‑photon detectors offer high efficiency and low jitter, yet integrating multiple SNSPDs on a single circuit has historically yielded system efficiencies below 0.2% due to low device yield. The study aims to integrate photon‑resolving detectors onto PICs to reduce optical losses, latency, and wiring complexity. The authors employ a micrometer‑scale flip‑chip technique to integrate SNSPDs onto various photonic integrated circuits. They integrated ten low‑jitter detectors on a single PIC with 100 % yield, achieving over 10 % system efficiency and enabling high‑fidelity on‑chip photon‑correlation measurements of non‑classical light.

Abstract

Photonic integrated circuits (PICs) have emerged as a scalable platform for complex quantum technologies using photonic and atomic systems. A central goal has been to integrate photon-resolving detectors to reduce optical losses, latency, and wiring complexity associated with off-chip detectors. Superconducting nanowire single-photon detectors (SNSPDs) are particularly attractive because of high detection efficiency, sub-50-ps timing jitter, nanosecond-scale reset time, and sensitivity from the visible to the mid-infrared spectrum. However, while single SNSPDs have been incorporated into individual waveguides, the system efficiency of multiple SNSPDs in one photonic circuit has been limited below 0.2% due to low device yield. Here we introduce a micrometer-scale flip-chip process that enables scalable integration of SNSPDs on a range of PICs. Ten low-jitter detectors were integrated on one PIC with 100% device yield. With an average system efficiency beyond 10% for multiple SNSPDs on one PIC, we demonstrate high-fidelity on-chip photon correlation measurements of non-classical light.