Ultra-fast single-photon counting with waveguide-integrated detectors for quantum technologies

Beutel F; Häußler M; Terhaar R; Wolff MA; Hartmann W; Walter N; Tillmann M; Wahl M; Röhlicke T; Ahangarianabhari M; Bülter A; Wernicke D; Perlot N; Rödiger J; Schuck C; Pernice WHP

Abstract

With recent advances in quantum technologies for applications such as communication, cryptography, computing, metrology and sensing, the performance and scalability of single-photon detection as a vital key component is becoming increasingly important. At the same time, ongoing efforts in the development of high-performance photonic integrated circuits (PIC) benefit the miniaturization and scalability of these quantum technologies. Waveguide-integrated superconducting nanowire single-photon detectors (WI-SNSPDs) allow to combine excellent performance metrics, such as high detection efficiency, low dark-count rates and low timing jitter below 20 ps with the scalability and functionality that PIC platforms such as Si3N4 provide. We have previously demonstrated broadband efficient single-photon detection with a single device over a range from visible to mid-infrared wavelengths and ultra-fast detector recovery times allowing for up to GHz count rates. Here, we present the utilization of WI-SNSPDs for discrete-variable quantum cryptography receivers with the complete photonic circuitry embedded together with the single-photon detectors on a single silicon chip, where the secret-key rates greatly benefit from the short recovery times of the detectors especially for metropolitan distances. We further realize a fully packaged 64 channel WI-SNSPD matrix for use in a wavelengthdivision multiplexed QKD setup.