High-rate quantum key distribution exceeding 110 Mb s^–1

By Wei Li, Likang Zhang, Hao Hao Tan, Yichen Lu, Shengkai Liao, Jia Huang, Hao Li, Zhen Wang, Haokun Mao, Bingze Yan and 7 more. Nature Photonics, 2023

256 citations recorded by the source corpus.

A quantum key distribution with a key rate of 115.8 Mb s^–1 is demonstrated over 10 km standard optical fibre. To this end, a high-speed and stable system, an integrated transmitter for low error modulation and multipixel superconducting nanowire single-photon detectors are developed. Quantum key distribution (QKD) can provide fundamentally proven secure communication. Towards application, the secret key rate (SKR) is a key figure of merit for any QKD system. The SKR has so far been limited to about a few megabits per second. Here we report a QKD system that is able to generate keys at a record high SKR of 115.8 Mb s^–1 over a 10 km standard optical fibre, and distribute keys over up to 328 km of ultralow-loss fibre. Such abilities are attributed to a multipixel superconducting nanowire single-photon detector with an ultrahigh counting rate, an integrated transmitter that can stably encode polarization states with low error, a fast post-processing algorithm for generating keys in real time and the high system clock rate operation. The results demonstrate the feasibility of practical high-rate QKD with photonic techniques, thus opening its possibility for widespread applications.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/dc0da23a3d95e7acc1cee2bb3e683c90e283dad2