Decoding chip and decoding method for quantum key distribution

Abstract

A decoding chip for quantum key distribution comprises: an input waveguide for receiving and transmitting an optical signal to be decoded; directional couplers which comprise a first directional coupler, a second directional coupler and a third directional coupler, wherein the first directional coupler is used for splitting input light into two beams of light, and the second directional coupler and the third directional coupler are used for achieving light quantum interference; a phase modulator which comprises a first phase modulator and a second phase modulator and is used for modulating thephase of the optical signal; a delay line structure which is used for delaying the optical signal and inhibiting the influence of the temperature on the bit error rate; and an output waveguide whichis used for outputting the demodulated optical signal. According to the decoding chip, the beam splitting ratio can be adjusted, and the double-time-gap pulsed light power is balanced, so that the interference visibility is optimized, and the bit error rate is reduced. The interference visibility of the decoding chip is insensitive to temperature change, namely the bit error rate caused by an optical device is insensitive to the temperature change.

Description

technical field [0001] The invention relates to the technical field of quantum communication, in particular to a decoding chip and a decoding method for quantum key distribution. Background technique [0002] Quantum key distribution (QKD) is a technology based on quantum physics and communication principles to achieve unconditional secure and confidential communication. In recent years, QKD has developed rapidly and has gradually entered commercialization. At present, the commercial quantum key system adopts phase-based and time-based quantum state encoding, and realizes the security of quantum communication through the preparation of strong attenuation coherent state and decoy state. However, because it is built from separate devices or some optical fiber devices, it has the disadvantages of discrete devices, low integration, large volume, poor long-term stability, and serious quantum state drift such as phase. Integrated photonics has the characteristics of good stabili...

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Problems solved by technology

However, the bit error rate of the current QKD chip is seriously affected by temperature, so the chip temperature is strictly required during operation.

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