On-Chip Detection of Entangled Photons by Scalable Integration of Single-Photon Detectors

TL;DR

This paper presents a scalable on-chip integration method for superconducting nanowire single-photon detectors (SNSPDs) on photonic circuits, achieving high yield and efficiency for quantum photonic applications.

Contribution

A novel flip-chip process enabling scalable integration of multiple SNSPDs on PICs with high yield and system efficiency.

Findings

Integrated 10 SNSPDs with 100% device yield

Achieved system efficiency beyond 10% for multiple detectors

Demonstrated high-fidelity on-chip photon correlation measurements

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.