基于FPGA的量子通信系统偏振态制备及控制集成化

Polarization State Preparation and Control Integration of a Quantum Communication System Based on a Field-Programmable Gate Array

在以偏振编码为基础的量子保密通信中,由于外界温度、应力以及光纤的本身缺陷等因素,使得偏振态无法保持长期稳定,增加系统的误码率,因此需进行偏振控制以维持通信系统正常运行。诱骗态已经成为现阶段量子通信网络的常规操作,利用诱骗光子作为偏振参考,有望实现系统偏振态长时间、不间断地锁定控制,提高通信效率。提出了利用现场可编程逻辑门阵列进行偏振态制备以及强光、单光子偏振控制于一体的系统偏振解决方案,将偏振态制备、强光偏振控制、单光子偏振控制单元集成在一个系统中,提高了系统的集成化,增加了系统管理的便捷性,实验测试偏振态制备单元可以根据需要产生不同的偏振态,经过强光偏振控制后,保真度可达99.11%±0.44%,经单光子偏振控制后保真度可达97.93%±0.96%,演示证明了方案的有效性和稳定性。

In quantum communication based on polarization encoding,the polarization state cannot be maintained for a long time because of the external temperature,stress,and defects in the optical fiber.This increases the bit error rate of the system.Therefore,polarization control is necessary to maintain robust operation of the communication system.Currently,decoy states are being widely used in quantum communication networks.Using decoy photons as a polarization reference,long-term and uninterrupted locking of the system polarization state can be achieved,and communication efficiency can be improved.In this study,an integrated polarization control system is built to control the polarization state preparation and single-photon transmission.The polarization state preparation unit,strong light polarization control unit,and single-photon polarization control unit are integrated into one system using a field-programmable gate array development board,which improves the integration of the system and makes system management more convenient.The experimental results show that the polarization state preparation unit can generate different polarization states as required,and the fidelity can reach 99.11%±0.44%after strong light polarization and 97.93%±0.96%after single-photon polarization control.These results demonstrate the effectiveness and stability of our proposed system.