Design And Implementation Of SPAD Single Photon Avalanche Diode Test System

With the continuous expansion of the application range of low-light detection technology,single-photon detectors have gradually become a hot topic at home and abroad.SPAD(single photon avalanche diode)is increasingly popular in the field of single photon detection due to its fast response speed and insensitivity to magnetic fields.More and more research institutions are investing in research on SPAD detectors.At present,the testing of SPAD device production mainly depends on foreign equipment.Different parameters need to be measured with the aid of different equipment.There are some problems such as incomplete test parameters,complex testing processes and high prices,which cannot meet the testing requirements of SPAD device production.To solve this problem,this paper designs a SPAD single photon avalanche diode test system.This design first studied the working characteristics and principles of SPAD devices,and then designed a test for parameters such as breakdown voltage,dark current,dead time,dark count,and photon detection efficiency of SPAD devices based on the test requirements of device characteristic parameters.Taking into account the performance of the entire system,the design finally achieved the combination of active and passive quenching circuits,low ripple reverse bias voltage and chip driving power,a digital counting circuit developed by FPGA to record avalanche events,and ALPHANOV’s CCS(Cool & Control Series),which high precision pulsed laser diode driver as light source.The avalanche signal processing circuit and power supply circuit were optimized and the PCB was manufactured.The software and hardware of system were verified and tested.The actual measurement results showed that the voltage ripple coefficient of the power system output was less than one thousandth,and the error coefficient was less than one hundredth.The detection dead time of the active quenching circuit is controlled at 72 ns,and a test platform is built according to the parameter test requirements.Finally,to meet the characteristics of SPAD devices,the breakdown voltage and dark current were tested.The relationship between dead time and quenching resistance,the relationship between dark count and dead time,the relationship between dark count andover-bias at different temperatures,and the relationship between photon detection efficiency and over-bias were verified,and the test results were analyzed.The design of the production test system for SPAD was completed.The actual test results show that the test system has the characteristics of low interference,easy operation and low cost.At the same time,the system adds a controllable high-precision pulsed laser light source,which makes up for the lack of testing of the characteristic parameters of the existing system,and demonstrated the rapid test of multiple characteristic parameters on the same test platform.It can be used to test the relationship between breakdown voltage,dark current,dark count,dead time,and photon detection efficiency with peripheral circuits and environmental factors to achieve the test of SPAD single photon avalanche diodes.