Research On Detector Refrigeration System In Quantum Key Distribution System

The emergence of quantum communication technology makes up the defect of the traditional communication technology security,its do not eavesdrop on do not copy attract more and more people for its special properties such as study,quantum key distribution is a branch of quantum communication technology,the core part of QKD system for the sender's light source module and receiver detector module,its demands detector with high quantum efficiency,strong responsivity,low dark count,etc.,how to design efficient performance and stable work of single photon detector,was an important subject for the development of quantum communication.This paper first introduces the working principle and safety of QKD system,analyzes the detection principle of single photon detector,and expounds the principle and characteristics of thermoelectric cooler technology and heat dissipation of vapor chamber.Because quantum key distribution system requirements of single photon detector with high stability,especially the stability of the detector in low temperature environment control,produce a great impact on the detection efficiency of the detector system,this paper adopt the thermoelectric cooler with Peltier effect of phenomena and the use of phase change heat dissipation vapor chamber,refrigeration cooling system of the single photon detector was designed,and the low temperature control circuit are designed.The optimization of the closed-loop temperature control system model,the design of the temperature acquisition circuit,the design of the analog PID control circuit,the design of TEC drive circuit and the design of the refrigerating box of the dual-channel detector are carried out.Through experimental tests,the temperature control precision of 0.01 ?,the maximum temperature difference are vapor chamber than aluminum alloy radiator was reduced by 60%,startup time shortens nearly doubled,thermal resistance decreased by about 20%,mean vapor chamber can provide stability to the detector cooling conditions,through the simulation,dual-channel detector cooling box solution in a single APD tube of heat leakage is reduced by about 41% on average,the total heat leakage was reduced by 20%,the last also simulated the radiator cooling capacity,cooling capacity meet the design requirements.