Contributed Talk 1a

contributed

Mon, 25 Aug 2025, 12:15 - 12:35

Experimental mode-pairing quantum key distribution surpassing the repeaterless bound
Likang Zhang (University of Science and Technology of China); Wei Li (University of Science and Technology of China); Jiawei Pan (University of Science and Technology of China); Yichen Lu (University of Science and Technology of China); Wenwen Li (University of Science and Technology of China); Zheng-Ping Li (University of Science and Technology of China); Yizhi Huang (Tsinghua University); Xiongfeng Ma (Tsinghua University); Feihu Xu (University of Science and Technology of China); Jianwei Pan (University of Science and Technology of China)
[abstract]
Abstract: We demonstrate a practical high-performance mode-pairing quantum key distribution system that is able to surpass the repeaterless key rate bound using commercial lasers. We propose a frequency tracking scheme to address phase fluctuations and a theoretical model to analyze the phase noise and optimize the system parameters. Our system achieves a secret key rate of 47.8 bit/s over 403 km standard fiber, which is 2.92 times of the repeaterless bound. Furthermore, we compare the performance between MP-QKD and no-phase-locking TF-QKD under various practical conditions and show that MP-QKD exhibits superior performance at short distances with low error rates, while TF-QKD is more advantageous for long distances with consistent error rates.