【摘要】 介绍了最近完成的长距离长期稳定的量子密钥分发系统.该系统利用往返光路补偿光纤偏振抖动和相位漂移的原理,采用结电容平衡魔T网络耦合的单光子探测技术,在50·6km单模光纤中实现了长时间(大于12h)稳定的量子密钥分发实验.单脉冲平均光子数为0·07,误码率为4%,其中单光子探测器的探测效率大于5%,单脉冲暗计数低于2·9×10-6.更多还原

【Abstract】 A stable long-distance quantum key distribution system which has been just completed in our laboratory is demonstrated in this paper. The idea of “plug and play" was adopted to automatically compensate the polarization mode dispersion and phase shift. A symmetrical capacitance-balance technique and magic-T network were used in the single-photon detection module, wherein a detection efficiency of more than 5% and a dark count probability of lower than 2.9×10~-6/pulse were achieved. As a result, we have realized stable (longer than 12 h) quantum key distribution experiment in 50.6 km single mode fiber with mean photon number of 0.07 and quantum bit error rate of 4%.更多还原