5-GHz chip-based quantum key distribution with 1Mbps secure key rate over 150 km

TL;DR

This paper presents a 5-GHz integrated quantum key distribution system achieving over 1 Mbps secure key rate at 150 km, significantly advancing practical high-speed quantum communication over long distances.

Contribution

Developed a novel polarization-state preparation method and integrated system that substantially improves secure key rates for long-distance QKD.

Findings

Secure key rate of 1.076 Mbps at 150 km

Achieved 105 kbps at 200 km

Enabled high-resolution video calls with one-time-pad encryption

Abstract

Quantum key distribution (QKD) enables secure communication by harnessing the fundamental principles of quantum physics, which inherently guarantee information-theoretic security and intrinsic resistance to quantum computing attacks. However, the secure key rate of QKD typically decreases exponentially with increasing channel distance. In this work, by developing a novel polarization-state preparation method, an ultra-low time-jitter laser source and superconducting nanowire single-photon detectors, we demonstrate a 5-GHz integrated QKD system featuring ultra-low quantum bit error rates (QBERs). The system achieves secure key rates of 1.076 Mbps at 150 km and 105 kbps at 200 km over standard single-mode fiber channels, respectively. Our system substantially enhances the secure key rate, enabling high-resolution video calls with one-time-pad encryption over intercity backbone QKD links. This work represents a significant step forward in the development of high-performance practical QKD systems.