Characteristics and use of APD in optical rangefinders

摘要

Photodiodes are commonly used as detectors in opticalrangefinders. However, one drawback is that good accuracy cannot beobtained when the distance is relatively long. This has in turn led tothe occasional use of the APD (avalanche photodiode) because of the longdistance accuracy its internal gain mechanism provides. One of the mostessential characteristics required in this application is the timeresponse property. Since the photodiode is more stable in operation, itstime response tends to be less affected by the type of operatingenvironments. APD time response, on the other hand, is more vulnerable,tending to be easily affected by the environment. This has to be takeninto account during APD operation and handling. In studying ways to makethe APD more resistant to different operating environments we mainlyconcentrated on the time pickoff technique. Results of that study arerelated here