12公里光纤上的LLO CV-QKD系统演示
Demonstration of an LLO CV-QKD system over 12 km of optical fiber
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中文总结 AI 辅助
本研究演示了12公里光纤上采用独立激光器的LLO CV-QKD系统，其在渐近和有限尺寸 regime 下分别实现5.11 Mbit/s和4.67 Mbit/s的密钥率，为城域CV-QKD部署奠定了基础。
中文摘要 AI 辅助
连续变量量子密钥分发（CV-QKD）有望实现高密钥率，且可与经典光束在单根光纤内无缝集成。多年来，相关方案通过将本地振荡器参考信号与量子信道一同传输来实现，这为窃听者打开了安全漏洞，也限制了潜在应用。在此，我们报告一种使用完全独立的发射机和接收机激光器（本地振荡器源）的高斯CV-QKD实现方案，其传输距离为12公里光纤卷。该系统采用包含约10^7个相干态的逻辑帧进行实验评估，每个逻辑帧由10个独立处理的子帧组成，每个子帧包含约10^6个状态；在可信设备模型下，我们在渐近和有限尺寸两种 regime 中评估了安全性。完整的经典后处理模块能够恢复信道参数，并在渐近 regime 中提取出5.11 Mbit/s的密钥率，在有限尺寸 regime 中提取出4.67 Mbit/s的密钥率，这与理论预测表现出良好的一致性。本研究为严格安全约束下CV-QKD在城域光纤中的部署奠定了基础。
英文摘要
Continuous-variable quantum key distribution (CV-QKD) promises high rates and seamless integration with classical beams within a single optical fiber. Over the years, implementations have been performed by transmitting a local oscillator reference along with the quantum channel, opening security loopholes for eavesdroppers and limiting potential applications. Here, we report on a Gaussian CV-QKD implementation using fully independent transmitter and receiver lasers (local-oscillator sources) over a 12 km fiber spool. The system was experimentally evaluated using logical frames containing approximately $10^7$ coherent states, each composed of ten independently processed subframes of approximately $10^6$ states, and security was assessed in both asymptotic and finite-size regimes under a trusted-device model. The full-fledged classical post-processing is capable of recovering the channel parameters and extracting secret key rates of 5.11 Mbit/s in the asymptotic regime and 4.67 Mbit/s in the finite-size regime, showing good agreement with theoretical predictions. This work establishes the foundation for metropolitan fiber deployment of CV-QKD under strict security constraints.
