Method and device for heterodyne detection using an avalanche photodiode, of amplitude-modulated light radiation, and applications to telemetry

摘要

The device comprises a photodetector 1 consisting of an avalanche photodiode included in a biasing electrical circuit, at least two light sources 3, 4 emitting, simultaneously towards the avalanche photodiode 1, respectively two light radiations which are amplitude modulated at the frequencies f1 and f0, and a detection means 5 connected to a terminal of the avalanche photodiode 1 for detecting the interference (beat) electrical signal having the intermediate frequency f1-f0 present on the said terminal of the photodiode. <IMAGE>