基于量子密钥分发的单光子探测器初步设计与实现

发布时间：2018-02-10 03:57

本文关键词： 量子密钥分发单光子探测器淬灭电路最佳反偏电压暗计数　出处：《电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着信息时代的到来,传统密码学的安全问题越来越让人们担忧,因其具有被破译的风险,无法保证信息绝对安全的传输。量子密码术因为其无条件保证通信安全性的优势,受到人们越来越多的关注。而作为量子密码术中必不可少的器件——单光子探测器,其性能的优劣对量子通信系统的传输码率、误码率和传输距离有很大影响,因而单光子探测技术的研究对于量子通信系统具有举足轻重的作用。本文首先介绍了量子密码术通信协议及其关键器件,而后对单光子探测器的探测原理进行了具体研究,并对单光子探测器的三种淬灭模式进行了对比分析。然后提出了基于时序控制的单光子探测器淬灭电路。电路包括直流偏压源模块、信号提取模块、制冷模块以及时序控制模块。直流偏压源模块在88~250V之间调节,可为APD提供所需的大电压以及快速增加的电流;信号提取模块包括前置放大电路以及比较器,前置放大电路采用跨阻放大器,其噪声小、频带宽,能够无失真的对信号进行放大,比较器采用TLV3501芯片,传输延迟小,能够快速的提取APD的雪崩信号;制冷模块利用帕尔贴对APD进行制冷,并通过FPGA控制帕尔贴的输出功率,能够灵活的对APD工作温度进行控制;时序控制模块利用FPGA对单光子探测器的淬灭时间以及恢复时间进行精确控制。最终完成了单光子探测器的设计。最后搭建了单光子探测器的实验系统,并对各项单光子探测器的性能指标进行了测试,包括对单光子探测器在不同温度下的暗计数和探测效率的测试。通过暗计数与探测效率的测试,找出能够让单光子探测器发挥最佳性能的反偏电压。然后对暗计数的稳定性以及时间分辨率进行了测试。
[Abstract]:With the advent of the information age, the security of traditional cryptography has become more and more worrying, because it has the risk of being deciphered, it can not guarantee the absolutely secure transmission of information, and quantum cryptography has the advantage of unconditionally guaranteeing the security of communication. As an indispensable device in quantum cryptography, the performance of single photon detector has great influence on the transmission rate, bit error rate and transmission distance of quantum communication system. Therefore, the research of single photon detection plays an important role in quantum communication system. Firstly, the quantum cryptography communication protocol and its key devices are introduced in this paper, and then the detection principle of single photon detector is studied in detail. Three quenching modes of single photon detector are compared and analyzed. Then the quenching circuit of single photon detector based on time sequence control is proposed. The circuit includes DC bias source module and signal extraction module. Refrigeration module and timing control module. The DC bias source module is adjusted between 88V and 250V, which can provide the APD with large voltage and fast increasing current. The signal extraction module includes preamplifier circuit and comparator. The preamplifier uses transresistive amplifier, which can amplify the signal without distortion because of its low noise and frequency bandwidth. The comparator uses TLV3501 chip, and the transmission delay is small, and the avalanche signal of APD can be extracted quickly. The refrigeration module can control the working temperature of APD flexibly by controlling the output power of APD through FPGA. The timing control module uses FPGA to accurately control the quenching time and recovery time of the single-photon detector. Finally, the design of the single-photon detector is completed. Finally, the experimental system of the single-photon detector is built. The performance indexes of single-photon detectors are tested, including the dark counting and detection efficiency of single-photon detectors at different temperatures. The reverse bias voltage which can make the single photon detector perform the best performance is found. Then the stability of dark count and the time resolution are tested.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN918.4;O413

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