自由空间量子密钥分配系统中接收端设计改进  

Improved design for the receiver of free space quantum key distribution system

作　　者：吴建荣[1] 朱冰[1] 

机构地区：[1]中国科学技术大学电子工程与信息科学系,合肥230027

出　　处：《仪器仪表学报》2010年第10期2216-2220,共5页Chinese Journal of Scientific Instrument

摘　　要：对自由空间量子密钥分配系统中接收端设计进行改进研究。采用琼斯矩阵方法分析了系统误码率和接收端光学元件光学特性的关系。分析表明,用来随机选择测量基的器件——偏振无关分束器(NPBS)的偏振相移特性的误差是系统误码的重要来源。提出对光路布置的设计改进方案,在这一方案中,只对NPBS的透射p光与s光的相移差有性能要求,可以降低接收端NPBS的偏振相移误差对误码率的影响。采用改进后的NPBS和普通商品NPBS进行了室外200m量子密钥分配的对比实验。实验结果与理论预期符合基本一致,改进NPBS的设计及接收端光学系统的光路布置使系统误码率降低了2.6%,证明了对接收端设计方案改进的有效性。An improved design for the receiver of free space quantum key distribution system was studied. Jones matrix method was used to analyze the relationship between the system bit error rate and optical characteristic of the devices in the receiver of the free space quantum key distribution system. Analysis result indicated that the phase shift difference for different polarized light passing through the non polarizing beam splitter （NPBS） was the important source of the system bit error rate. An improved design for the arrangement of the optical path was proposed, in which the system error bit rate could be decreased by only declining the phase shift difference between the p light and the s light in the transmitting optical path for the NPBS. An outdoor 200 m quantum key distribution experiment was carried out using the improved NPBS and commercially available one. Through improving the NPBS and the arrangement of receiver optical path, the system bit error rate was declined by 2.6%, which proved the validity of the improved design for the receiver.

关 键 词：量子密钥分配 误码率 偏振无关分束器 

分 类 号：TN918[电子电信—通信与信息系统]