Zhang Chun-Hui, Wang Dong, Zhou Xing-Yu, Wang Shuang, Zhang La-Bao, Yin Zhen-Qiang, Chen Wei, Han Zheng-Fu, Guo Guang-Can, Wang Qin
Opt Express. 2018 Oct 1;26(20):25921-25933. doi: 10.1364/OE.26.025921.
Quantum key distribution (QKD) offers information-theoretic security verified by quantum mechanics to share keys between legitimate users. Most of the existing QKD systems employ active decoy states based on weak coherent sources (WCS). Meanwhile, parametric down-conversion (PDC) sources are seldom used due to several of their shortcomings. In the present work, to show the superiority of PDC sources, we have accomplished a proof-of-principle demonstration of a PDC source-based QKD with over 40 dB based on the one-way BB84 protocol. In this QKD system, a novel passive decoy-state scheme-secure to coherent attacks-is proposed, using several built-in decoy states for parameter estimation. This not only avoids intensity modulating errors, but also diminishes all possible information leakage from the intensity modulating process. The experimental results show a significantly enhanced performance compared with existing PDC source-based QKD systems. In addition, it exhibits some superiority even over active decoy-state QKD systems based on WCS.
量子密钥分发（QKD）提供了由量子力学验证的信息理论安全性，用于在合法用户之间共享密钥。现有的大多数QKD系统采用基于弱相干源（WCS）的主动诱骗态。同时，由于参数下转换（PDC）源存在一些缺点，很少被使用。在本工作中，为了展示PDC源的优越性，我们基于单向BB84协议完成了一个基于PDC源的QKD的原理验证演示，其安全性能超过40 dB。在这个QKD系统中，提出了一种新颖的、对相干攻击安全的被动诱骗态方案，使用几个内置诱骗态进行参数估计。这不仅避免了强度调制误差，还减少了强度调制过程中所有可能的信息泄露。实验结果表明，与现有的基于PDC源的QKD系统相比，性能有显著提高。此外，它甚至比基于WCS的主动诱骗态QKD系统还表现出一些优越性。
