The Automatic Measurement System For SNSPDs

With the development of quantum communication,quantum computation,quantum imaging and a series of weak light detection technology,the requirement of superior performance of single photon detector is more and more urgent.Superconducting nanowire single photon detector with fast response speed,low dark count rate,high detection efficiency and a series of advantages,has attracted wide attention in the industry.The measurement system is an important part of the single photon detection,which has a significant influence on the detection results.This thesis aims at the fabrication of the automatic measurement System for SNSPDs which is controlled by LabVIEW control program.Under the control of LabVIEW program,each laboratory instrument is organized to work orderly,as a result,the measurement System can run automatically,and improve the efficiency of the experiment.Firstly,this thesis introduces principles and applications of single-photon detectors,and then summarizes the shortcomings of traditional measurement system.Then we introduces the programming language LabVIEW which is used in the experiment,and how to use it to control the laboratory instruments.Then we show in detail the construction of our automatic measurement system,as well as the various laboratory instruments which are used in the system.Finally we analyze polarization characteristics of the system using the self-made polarization measurement module,and,by means of improving the polarization controller,we optimize the polarization stability of the system,which provide constructive suggestions for the further optimization of the polarization stability of the system.In addition,a high speed and long distance switching matrix system is built.The system can effectively overcome the shortcomings of the traditional switching matrix:signal maximum transmission distance is limited and loss.Besides,the system has advantages of high fidelity and operation mode diversification,and can achieve signal switching,signal superposition and other functions.