基于法拉第-麦克尔逊干涉检测的低误码差分相位编码实验系统  

A new differential phase shift quantum key distribution system with Faraday-Michelson interferometer

作　　者：魏正军[1] 万伟[2] 王金东[1] 廖常俊[1] 刘颂豪[1] 

机构地区：[1]华南师范大学信息光电子科技学院光子信息技术广东省高校重点实验室,广州510006 [2]广东广播电视大学,广州510091

出　　处：《物理学报》2011年第9期411-417,共7页Acta Physica Sinica

基　　金：广州市科技支撑计划(批准号:2008Z1-D501);广东省工业攻关项目(批准号:2007B010400009);中国科学院量子信息技术重点实验室开放课题资助的课题~~

摘　　要：采用法拉第-麦克尔逊干涉仪检测的方法实现了基于强度调制的弱相干光脉冲的差分相位编码系统.系统针对各个可能引起误码的关键环节提出并采用了相关物理方案来减小系统的误码,采用可以产生高精度任意频率的小数分频的锁相环时钟发生器为系统提供时钟信号,减小了由于通信双方时域不匹配而带来的误码;采用单光子计数水平下高精度实时测量行波相位调制器半波电压的新方法减小了由于不准确加载相位电压引起的误码;采用单光子计数水平下的法拉第-麦克尔逊干涉仪解决自动补偿单光子脉冲干涉的偏振匹配问题,提高了系统的干涉对比度,实验结果实现了50km传输距离时误码率为3.9%的量子密钥分发.A new differential phase shift quantum key distribution system based on the intensity modulator with Faraday-Michelson interferometer is demonstrated experimentally. Some technologies are employed to improve the performance of the quantum key distribution system. These technologies include the clock generation technology of arbitrary frequency by a small scale frequency-split and phase locked loop scheme, the new method to acquire the half-wave voltage of the phase modulator with a high accuracy in the condition of the single photon count, and the auto-compensated polarization technology by the Faraday-Michelson interferometer. Finally, the quantum key distribution is achieved with a quantum bit error rate of 3.9% when the transmission distance reaches 50 km.

关 键 词：量子保密通信 量子密钥分发 差分相位编码 法拉第-麦克尔逊干涉仪 

分 类 号：O431.2[机械工程—光学工程] TN918.1[理学—光学]