DEVICE FOR QUANTUM DISTRIBUTION OF A SYMMETRIC BIT SEQUENCE AT A SUBCARRIER FREQUENCY OF MODULATED RADIATION USING A 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, which includes a coherent radiation source connected by means of a fiber-optic path, an optical insulator, an optical phase modulator and an attenuator, as well as a receiver unit consisting of an input polarization light divider, two optical phase modulators connecting the radiation of a polarization light divider, an optical circulator and a spectral filter that separates and directs optical radiation to the corresponding arms of a balanced detector, 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 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 which are connected to an electric phase modulator, which is also connected to optical phase modulators in the receiver unit, in addition, a signal analyzer is present in the receiver unit, coupled to a computer and the output of a balanced detector.

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

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