High-rate quantum key distribution exceeding 110 Mb/s

TL;DR

This paper demonstrates a high-rate quantum key distribution system achieving a record SKR of 115.8 Mb/s over 10 km fiber, utilizing advanced detectors, stable encoding, and fast processing for practical secure communication.

Contribution

The paper introduces a QKD system with a record high secret key rate enabled by novel detectors, stable encoding, and real-time post-processing, surpassing previous SKR limits.

Findings

Achieved a secret key rate of 115.8 Mb/s over 10 km fiber.

Distributed keys over 328 km of ultra-low-loss fiber.

Demonstrated practical high-rate QKD with photonic techniques.

Abstract

Quantum key distribution (QKD) can provide fundamentally proven security for secure communication. Toward application, the secret key rate (SKR) is a key figure of merit for any QKD system. So far, the SKR has been limited to about a few megabit-per-second. Here we report a QKD system that is able to generate key at a record high SKR of 115.8 Mb/s over 10-km standard fibre, and to distribute key over up to 328 km of ultra-low-loss fibre. This attributes to a multi-pixel superconducting nanowire single-photon detector with ultrahigh counting rate, an integrated transmitter that can stably encode polarization states with low error, a fast post-processing algorithm for generating key 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.