Application Note

Avalanche Photodiodes (APDs) - A User Guide

Source: Excelitas Technologies

Avalanche photodiode detectors (APDs) have and will continue to be used in many diverse applications such as laser range finders, data communications or photon correlation studies. This paper discusses APD structures, critical performance parameter and excess noise factor. For low-light detection in the 200- 1150 nm range, the designer has three basic detector choices - the silicon PIN detector, the silicon APD and the photomultiplier tube (PMT).

APDs are widely used in instrumentation and aerospace applications, offering a combination of high speed and high sensitivity unmatched by PIN detectors, and quantum efficiencies at > 400 nm unmatched by PMTs.