Single photon detector on avalanche photodiode

The technology of quantum cryptography, based on the quantum properties of light, allows a random sequence of bits to be transmitted over an unprotected communication channel in such a way that an intruder's interference in the transmission process generates additional noise in the channel and is detected by legitimate users. One of the important elements of the quantum key distribution system is a single photon detector. In this work proposed quantum cryptographic system that generates only an orthogonal basis (vertical and horizontal) has one semiconductor diode laser used to generate information and synchronization photons and functional diagram of the device for registration of single photons. The developed device allows increasing the quantum efficiency of registration up to 45%.