Honjo T, Nam S W, Takesue H, Zhang Q, Kamada H, Nishida Y, Tadanaga O, Asobe M, Baek B, Hadfield R, Miki S, Fujiwara M, Sasaki M, Wang Z, Inoue K, Yamamoto Y
NTT Basic Research Laboratories, NTT Corporation, Atsugi-shi 243-0198, Japan.
Opt Express. 2008 Nov 10;16(23):19118-26. doi: 10.1364/oe.16.019118.
We report the first entanglement-based quantum key distribution (QKD) experiment over a 100-km optical fiber. We used superconducting single photon detectors based on NbN nanowires that provide high-speed single photon detection for the 1.5-mum telecom band, an efficient entangled photon pair source that consists of a fiber coupled periodically poled lithium niobate waveguide and ultra low loss filters, and planar lightwave circuit Mach-Zehnder interferometers (MZIs) with ultra stable operation. These characteristics enabled us to perform an entanglement-based QKD experiment over a 100-km optical fiber. In the experiment, which lasted approximately 8 hours, we successfully generated a 16 kbit sifted key with a quantum bit error rate of 6.9 % at a rate of 0.59 bits per second, from which we were able to distill a 3.9 kbit secure key.
我们报告了首个基于纠缠的量子密钥分发（QKD）在100公里光纤上的实验。我们使用了基于氮化铌纳米线的超导单光子探测器，其为1.5微米电信波段提供高速单光子探测；一个由光纤耦合的周期性极化铌酸锂波导和超低损耗滤波器组成的高效纠缠光子对源；以及具有超稳定运行特性的平面光波电路马赫-曾德尔干涉仪（MZIs）。这些特性使我们能够在100公里光纤上进行基于纠缠的QKD实验。在持续约8小时的实验中，我们成功以每秒0.59比特的速率生成了一个量子误码率为6.9%的16千比特筛选密钥，从中我们能够提取出一个3.9千比特的安全密钥。
