Polarization coding QKD system and method based on silicon optical integrated chip

Abstract

The invention discloses a polarization coding QKD (quantum key distribution) system based on a silicon optical integrated chip, which comprises a transmitting end and a receiving end, and is characterized in that the transmitting end and the receiving end respectively comprise a random number generator, an FPGA and a quantum chip, wherein the FPGA is used for controlling the quantum chip and performing communication through a classic channel; the random number generator is used for generating a modulation signal; in a transmitting end, an FPGA generates a pulse signal to drive an intensity modulator to generate a direct current bias voltage to drive an adjustable attenuator, and drives a phase modulator and a polarization modulator to carry out phase randomization and polarization state preparation according to the generated modulation signal, and then demultiplexing is carried out at a receiving end through a polarization demultiplexer; and in a receiving end, the FPGA drives a polarization demodulator according to a modulation signal generated by a random number generator, randomly selects a measurement base to measure the received polarization state, counts the number of photons through a single photon detector, and records the photon count as a measurement result. According to the invention, the bit error rate of the system is reduced, and the transmission distance of the system is improved.

Description

technical field [0001] The invention relates to the technical field of micro-nano optoelectronics and quantum communication, in particular to a polarization coding QKD system and method based on a silicon photonics integrated chip. Background technique [0002] As an important part of quantum communication, QKD technology is mainly used for the generation and distribution of encryption keys. In theory, QKD can realize absolutely secure confidential communication, and its security is guaranteed by physical laws such as the principle of uncertainty and the principle of non-replicating quantum states. [0003] QKD technology can use entangled quantum states for key distribution: send a group of entangled quantum states to two trusted terminals respectively, so that the two communicating parties share the entangled state; then at the terminal, the two parties randomly select different base vectors Perform measurement; both parties inform the other party of the base vector used ...

AI Technical Summary

Problems solved by technology

However, due to the unsatisfactory roundness of the fiber, residual stress, etc., the birefringence effect will occur in the fiber, making it difficult to maintain a stable polarization state in the fiber.

[0007] Therefore, it is necessary to further improve the existing QKD-based system to overcome the problems of large volume, complex structure, poor stability, high cost and unstable polarization state transmission in optical fibers.

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