DEVICE FOR QUANTUM DISTRIBUTION OF A SYMMETRIC BIT SEQUENCE AT A SUBCARRIER FREQUENCY OF MODULATED RADIATION USING A DOUBLE HOMODYNE RECEPTION METHOD Russian patent published in 2021 - IPC H04L9/08 

FIELD: photonic quantum communication systems.

SUBSTANCE: invention relates to photonic quantum communication systems. The device contains a sender unit, including a coherent radiation source connected by means of a fiber-optic path to an optical insulator, an optical phase modulator and an attenuator, as well as a receiver unit consisting of an input optical beam splitter, a polarization light divider, four optical phase modulators connecting the radiation of two polarization light dividers, two optical circulators and two spectral filters that separate and direct optical radiation in the corresponding arms of two balanced detectors, in addition, the sender’s unit includes a computer and an FPGA connected to it, a control voltage generator (CVG) and an input of an electric phase modulator are connected to the FPGA on the sender’s side, the output of which is connected to an optical phase modulator, in addition, a phase-lock loop system (PLL) is connected to the electric phase modulator, which in turn is coupled to a control voltage generator, the FPGA is also connected to the sender’s SFP standard module, which, in turn, via a fiber-optic communication line is connected to the SFP standard module of the receiver unit, the receiver unit also includes a computer, an FPGA coupled to it, a low-pass filter and a control voltage generator connected to the FPGA, a PLL is connected to the control voltage generator, the outputs of the PLL are connected to an electric phase modulator, two outputs of which are connected directly to optical phase modulators in the receiver unit, and two more outputs are connected to optical phase modulators via a phase shifter, in addition, there are signal analyzers are connected to computers and outputs of balanced detectors in the receiver unit.

EFFECT: providing a device for quantum distribution of symmetric bit sequences with an expanded scope of application.

1 cl, 1 dwg