DISCRIMINATING PHOTO COUNTS AND DARK COUNTS IN AN AVALANCHE PHOTODIODE

摘要

The output of an avalanche photodiode (APD) comprises a “photocurrent” component comprising photon initiated events resulting from the interaction of photons with the APD and a “dark current” component comprising dark carrier events arising in the APD even when the APD is not exposed to light. Differences in the pulse height distributions of photon initiated events and dark carrier initiated events are used to statistically discriminate between photocurrent and dark current components of APD output.

主权项

1. A photoreceiver comprising:
a. a photodiode arranged to emit an electrical pulse as a result of interaction with a photon and emitting a dark pulse absent interaction with a photon; b. a decision circuit to designate a pulse emitted by said photodiode as a photon induced pulse if a measured parameter of said electrical pulse exceeds a threshold value of said measured parameter, said threshold comprising a value of said measured parameter selected to maximize a difference between a pulse height distribution of plural photon induced pulses emitted by said photodiode and a pulse height distribution of plural dark pulses emitted by said photodiode; and c. a timing unit to provide a temporal reference of said photon induced pulses emitted by said photodiode.