5‐GHz Chip‐Based Quantum Key Distribution With 1 Mbps Secure Key Rate Over 150 km
Guo‐wei Zhang, Sheng‐Teng Zheng, Yao Xiao, Fang‐Xiang Wang, Wen-Jing Ding, Dianpeng Wang, Penglei Hao, Li Zhang, Jia-Lin Chen, Yuyang Ding, Shuang Wang, De‐Yong He, Zhen−Qiang Yin, Zheng Zhou, Hao Li, Lixing You, Guang‐Can Guo, Wei Chen, Zheng‐Fu Han · Laser & Photonics Review · 2026
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, through the development of a novel polarization‐state preparation method, an ultra‐low time‐jitter laser source, and superconducting nanowire single‐photon detectors, a 5‐GHz integrated QKD system featuring ultra‐low quantum bit error rates (QBERs) is demonstrated. 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. The system substantially enhances the secure key rate, enabling the implementation of 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.