关键词: 量子密钥分发/
测量设备无关/
误码率/
分束器
English Abstract
Analysis on performance optimization in measurement-device-independent quantum key distribution using weak coherent states
Wu Cheng-Feng1,Du Ya-Nan1,
Wang Jin-Dong1,
Wei Zheng-Jun1,
Qin Xiao-Juan2,
Zhao Feng3,
Zhang Zhi-Ming1
1.Laboratory of Nanophotonic Functional Materials and Devices (SIPSE), and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou 510006, China;
2.Engineering Technology Department, Guangdong Polytechnic Institute, Guangzhou 510091, China;
3.School of Physics and Telecommunication Engineering, Shaanxi University of Technology, Hanzhong 723000, China
Fund Project:Project supported by the Major Research Plan of the National Natural Science Foundation of China (Grant No. 91121023), the National Natural Science Foundation of China (Grant Nos. 61378012, 11374107, 60978009, 61108039, 61401176, 61401262), the Natural Science Foundation of Guangdong Province, China (Grant Nos. 2014A030310205, 2015A030313388), the National Basic Research Program of China (Grant No. 2011CBA00200), and the Application-oriented Special Scientific Research Fund of Application Type of Guangdong Province, China (Grant No. 2015B010128012).Received Date:03 December 2015
Accepted Date:12 February 2016
Published Online:05 May 2016
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 quasisingle- 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 efficiency) 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.
Keywords: quantum key distribution/
measurement-device-independent/
quantum bit error rate/
beam splitter
