High Speed and High Efficiency Travelling Wave Single-Photon Detectors Embedded in Nanophotonic Circuits

TL;DR

This paper presents a superconducting nanowire single-photon detector integrated with nanophotonic circuits, achieving high efficiency, low dark counts, and ultrashort timing jitter, enabling advanced quantum photonics applications.

Contribution

The authors demonstrate a scalable, high-efficiency, low-jitter on-chip single-photon detector embedded in silicon photonics, overcoming previous limitations in detection efficiency and integration.

Findings

Achieved 91% on-chip detection efficiency at telecom wavelengths.

Observed low dark count rates without efficiency loss.

Demonstrated ultrashort 18 ps timing jitter and ballistic photon transport.

Abstract

Ultrafast, high quantum efficiency single photon detectors are among the most sought-after elements in modern quantum optics and quantum communication. High photon detection efficiency is essential for scalable measurement-based quantum computation, quantum key distribution, and loophole-free Bell experiments. However, imperfect modal matching and finite photon absorption rates have usually limited the maximum attainable detection efficiency of single photon detectors. Here we demonstrate a superconducting nanowire detector atop nanophotonic waveguides which allows us to drastically increase the absorption length for incoming photons. When operating the detectors close to the critical current we achieve high on-chip single photon detection efficiency up to 91% at telecom wavelengths, with uncertainty dictated by the variation of the waveguide photon flux. We also observe remarkably low dark count rates without significant compromise of detection efficiency. Furthermore, our detectors are fully embedded in a scalable silicon photonic circuit and provide ultrashort timing jitter of 18ps. Exploiting this high temporal resolution we demonstrate ballistic photon transport in silicon ring resonators. The direct implementation of such a detector with high quantum efficiency, high detection speed and low jitter time on chip overcomes a major barrier in integrated quantum photonics.