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.
@article{arxiv.2512.24094,
title = {5-GHz chip-based quantum key distribution with 1Mbps secure key rate over 150 km},
author = {Guo-Wei Zhang and Sheng-Teng Zheng and You Xiao and Fang-Xiang Wang and Wen-Jing Ding and Dianpeng Wang and Penglei Hao and Li Zhang and Jia-Lin Chen and Yu-Yang Ding and Shuang Wang and De-Yong He and Zhen-Qiang Yin and Zheng Zhou and Hao Li and Lixing You and Guang-Can Guo and Wei Chen and Zheng-Fu Han},
journal= {arXiv preprint arXiv:2512.24094},
year = {2026}
}