SYSTEM AND METHOD FOR COMPENSATING FOR TIME SHIFT OF OPTICAL PULSES IN QUANTUM CHANNELS OF QUANTUM KEY DISTRIBUTION DEVICE WITH UNTRUSTED CENTRAL NODE Russian patent published in 2025 - IPC H04L9/08 H04B10/70 

FIELD: quantum distribution of keys.

SUBSTANCE: invention relates to quantum key distribution with an untrusted central node (QKD UCN). Technical result is achieved by implementing a system for compensating for the time shift of optical pulses in quantum channels of a quantum key distribution device (QKD) with an untrusted central node (UCN), in which UCN contains a controlled optical delay line (ODL) placed in one of the input arms of the beam splitter, on which interference of input optical pulses occurs, wherein the controlled ODL is included in a feedback loop with single photon detectors by means of a control unit (CU) and is configured to control overlapping of laser pulses coming from transmitting units (TU) to the UCN with accuracy of up to a unit of picoseconds.

EFFECT: improved visibility of interference in real operating conditions of the device, thereby increasing the maximum distance between TU and increasing the speed of generating a secret key.

2 cl, 3 dwg