The APD (avalanche photodiode) is a high sensitivity photodiode that operates at high speeds and high gain by applying a reverse bias. Delivers a higher S/N than PIN photodiodes and is widely used in optical rangefinders, spatial light transmission, scintillation detectors, etc.
InGaAs APDs are high-speed, high sensitivity photodiodes having an internal gain mechanism, and can be used in measurements at very low light levels.They are mainly used for optical fiber communications, distance measurement and spatial light transmission, etc.