HIGH-SPEED AUTOCOMPENSATION SCHEME OF QUANTUM KEY DISTRIBUTION Russian patent published in 2018 - IPC H04L9/08 

FIELD: cryptography.

SUBSTANCE: invention relates to quantum cryptography, which lies in the field of information protection. Communication system for transmitting a cryptographic key between the ends of a channel includes a transmitting node comprising a beam splitter, an electro-optical attenuator, an amplitude modulator, a phase modulator, a storage line, a Faraday mirror, a synchronization detector; receiving unit containing laser, avalanche photodiodes, beam splitter, circulator, delay line, phase modulator, polarizing beam splitter, Mach-Zehnder interferometer; and a quantum channel for connecting the specified nodes. In this case, the storage line is placed between the electro-optical phase modulator of the sender and the Faraday mirror.

EFFECT: technical result is an increase in the limiting frequency of the repetition of laser pulses at a fixed value of their width, which makes it possible to use an auto-compensating circuit at a frequency, the period of which is equal to the width of the laser pulse, which is the maximum possible result.

3 cl, 3 dwg