Fully integrated four-channel wavelength-division multiplexed QKD receiver

Optica. 2022. Vol. 9. No. 10. P. 1121–1130.

Beutel F., Brückerhoff-Plückelmann F., Gehring H., Vadim Kovalyuk, Philipp Zolotov, Gregory Goltsman, Pernice W.

Quantum key distribution(QKD) enables secure communication even in the presence ofadvancedquantumcomputers. However, scaling up discrete-variable QKD to high key rates remains a challenge due to the lossy nature ofquantum communication channels and the use of weak coherent states. Photonic integration and massive parallelization are crucial steps toward the goal of high-throughput secret-key distribution. We present a fully integrated photonic chip on silicon nitride featuring a four-channel wavelength-division demultiplexed QKD receiver circuit including state-of- the-art waveguide-integrated superconducting nanowire single-photon detectors (SNSPDs).With a proof-of-principle setup operated at a clock rate of 3.35 GHz, we achieve a total secret-key rate of up to 12.17 Mbit/s at 10 dB channel attenuation with low detector-induced error rates. The QKD receiver architecture is massively scalable and constitutes a foundation for high-rate many-channel QKD transmission. ©

Keywords: Quantum key distribution, superconducting single-photon detector