High-speed Continuous Variable Quantum Key Distribution System and Its Bit-Frame Synchronization Method

Abstract

The invention provides a high-speed continuous variable quantum key distribution system and a bit frame synchronization method thereof. The bit frame synchronization method comprises the following steps: Step one, a sender generates a set of special data used as a synchronous frame; Step two, the sender sends a coherent state to a receiver through a quantum channel; Step three, the receiver uses a balance homodyne detector to measure the displacement component of the coherent state; Step four, the receiver selects an appropriate alternate voltage determining threshold and a frame synchronization segment determining threshold to determine the synchronous frame according to structure information of the special data acquired through a classical channel in Step one; and Step five, synchronization fails if the receiver does not search the synchronous frame in the specified time, and the receiver needs to adjust the value of the alternate voltage determining threshold and the value of the frame synchronization segment determining threshold and reestablishes communication. According to the invention, the interference of external environmental factors to synchronization signals in the process of quantum key distribution can be effectively overcome, and synchronization between both sides of communication can be realized.

Description

technical field [0001] The invention relates to the technical field of optical fiber quantum communication, in particular to a high-speed continuous variable quantum key distribution system and a bit frame synchronization method thereof. Background technique [0002] Quantum key distribution enables legitimate communication parties to safely share keys in an untrusted quantum channel. Unlike discrete variable quantum key distribution protocols, continuous variable quantum key distribution encodes information in continuous quantum variables (regular shifts of coherent states and canonical momentum) and using high-efficiency and low-cost homodyne or heterodyne balance detection technology, this continuous variable quantum key distribution that abandons single-photon technology and has a higher key distribution rate has received close attention from the academic community . At present, the academic community has proposed many continuous variable quantum key distribution protoc...

AI Technical Summary

Problems solved by technology

However, unlike the traditional optical fiber communication system, the continuous variable quantum key distribution system transmits weak quantum signals, which are easily affected by the external environment, such as optical fiber jitter, external mechanical vibration, humidity and temperature, etc. These environmental factors affect the state of the quantum coherent state of the transmitted signal in the system

Therefore, the continuous variable quantum key distribution system cannot simply use the synchronization scheme of the traditional optical fiber communication system, but must use a synchronization scheme with quantum transmission characteristics

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