Operating quantum waveguide circuits with superconducting single-photon detectors

TL;DR

This paper demonstrates the integration of superconducting single-photon detectors with quantum waveguide circuits, achieving high-visibility two-photon interference and implementing quantum logic and metrology circuits, advancing scalable on-chip quantum information processing.

Contribution

It introduces the use of SSPDs in quantum waveguide circuits, showing improved interference visibility and enabling quantum gate and metrology operations at telecom wavelengths.

Findings

Achieved 92.3% two-photon interference visibility with SSPDs

Demonstrated controlled-NOT gate operation with SSPDs

Enabled quantum metrology circuits using SSPDs

Abstract

Advanced quantum information science and technology (QIST) applications place exacting de- mands on optical components. Quantum waveguide circuits offer a route to scalable QIST on a chip. Superconducting single-photon detectors (SSPDs) provide infrared single-photon sensitivity combined with low dark counts and picosecond timing resolution. In this study we bring these two technologies together. Using SSPDs we observe a two-photon interference visibility of 92.3\pm1.0% in a silica-on-silicon waveguide directional coupler at \lamda = 804 nm-higher than that measured with silicon detectors (89.9\pm0.3%). We further operated controlled-NOT gate and quantum metrology circuits with SSPDs. These demonstrations present a clear path to telecom-wavelength quantum waveguide circuits.