物理学报2016，Vol.65Issue(10)：100302-1-100302-10,10.DOI:10.7498/aps.65.100302
弱相干光源测量设备无关量子密钥分发系统的性能优化分析∗
Analysis on p erformance optimization in measurement-device-indep endent quantum key distribution using weak coherent states
摘要
Abstract
Measurement-device-independent quantum key distribution (MDI-QKD) is immune to all detection side-channel attacks, thus when combined with the decoy-state method, it can avoid the actual security loophole caused by quasi-single-photon source simultaneously. A practical weak coherent source is used as a quasi-single-photon source in the current MDI-QKD experiments; it may contain percentage of vacuum- and multi-photon pulses. Moreover, in order to study how the performance of the threshold detector affects the quantum bit error rate (QBER), we introduce the quality factor (the ratio of the dark count rate to the detection effciency) of the threshold detector. Here, through taking into account the weak coherent source, the quality factor of the threshold detector and the reflectivity of beam splitter, we deduce and evaluate the gain, the probability for successful Bell measurement, incorrect Bell measurement when Alice and Bob send pulses with different photon numbers which have a high probability to appear in weak coherent source, and then we obtain QBER in combination with the probabilities of different photon number states, besides, we also do some simulations. The simulations show how QBER varies with the reflectivity of beam splitter and the quality factor of the threshold detector when the average photon numbers per pulse from Alice and Bob are symmetric. Furthermore, the simulations show how QBER varies with the average photon number per pulse from Alice when average photon number per pulse from Bob is 0.1. Result shows that QBER is affected by the reflectivity of beam splitter, but QBER cannot reach the minimum value in Z basis encoding scheme when the average photon numbers per pulse from Alice and Bob are both 0.1 and the reflectivity of beam splitter is 0.5, which is different from X basis encoding and phase encoding. In addition, QBER increases with the increase of the quality factor of the threshold detector, which means that better performance of the threshold detector will reduce QBER. We show that QBER in Z basis encoding reaches the minimum value when reflectivity of beam splitter is 0.5 and there is large difference between in average photon number per pulse between two sides. In conclusion, for QBER, the effect from the reflectivity of beam splitter is equal to average photon numbers from the two arms only in X basis encoding and phase encoding. Our work will provide a reference for setting up a system with better performance.关键词
量子密钥分发/测量设备无关/误码率/分束器Key words
quantum key distribution/measurement-device-independent/quantum bit error rate/beam splitter引用本文复制引用
吴承峰,杜亚男,王金东,魏正军,秦晓娟,赵峰,张智明..弱相干光源测量设备无关量子密钥分发系统的性能优化分析∗[J].物理学报,2016,65(10):100302-1-100302-10,10.基金项目
国家自然科学基金重大研究计划(批准号:91121023)、国家自然科学基金(批准号:61378012,11374107,60978009,61108039,61401176,61401262)、广东省自然科学基金(批准号:2014A030310205,2015A030313388)、国家重点基础研究发展计划(批准号:2011CBA00200)、广东省科技计划(批准号:2014B090901016)和广东省应用型科技研发专项资金(批准号:2015B010128012)资助的课题 （批准号:91121023）
