AI 中文总结
研究实现用于量子协议的千兆赫兹速率全光纤有源偏振态分析仪，基于含铌酸锂电光相位调制器的光纤萨尼亚克干涉仪，能逐次试验主动重设测量基，经CHSH贝尔测试验证，具高速、高可见度、长期稳定性等优势，为量子通信协议提供平台。
AI 中文摘要
主动选择测量基是包括设备无关量子密钥分发、具有主动前馈的量子隐形传态和贝尔测试在内的量子协议的基础。高速运行对于最小化连续测量选择之间的延迟至关重要，能够实现更快的协议执行和更高的通信速率。在此，我们展示了一种千兆赫兹速率的全光纤偏振态分析仪，能够逐次试验地主动重新配置测量基，并通过执行CHSH贝尔测试进行了验证。该状态分析仪基于包含铌酸锂电光相位调制器的光纤萨尼亚克干涉仪，完全由现成的光纤组件构建而成。系统以1GHz的标称重复率运行，对CHSH贝尔测试进行动态偏振测量，实现高达99%的偏振可见度以及S = 2.6975±0.0005的违背，以前所未有的速率证明了纠缠。此外，该系统展示了出色的长期稳定性，在无需重新对准的情况下保持贝尔不等式违背超过6小时。这些结果确立了所提出的状态分析仪作为一个通用、可扩展的平台，适用于需要快速、可重新配置偏振态测量的量子通信协议。
英文摘要
Active selection of the measurement basis underpins quantum protocols including device-independent quantum key distribution, quantum teleportation with active feed-forward, and Bell tests. High-speed operation is crucial to minimize the latency between consecutive measurement choices, enabling faster protocol execution and higher achievable communication rates. Here, we demonstrate a GHz-rate all-fiber polarization state analyzer enabling active, trial-by-trial reconfiguration of the measurement basis, which we validate by performing a CHSH Bell test. The state analyzer is based on a fiber Sagnac interferometer incorporating a lithium niobate electro-optic phase modulator, built entirely using off-the-shelf fiber-optic components. Operating at a nominal repetition rate of 1 GHz, the system performs dynamic polarization measurements for the CHSH Bell test, achieving polarization visibilities up to 99% and a violation of $S = 2.6975 \pm 0.0005$, certifying entanglement at an unprecedented rate. Furthermore, the system demonstrates excellent long-term stability, preserving the Bell-inequality violation for more than 6 hours without realignment. These results establish the proposed state analyzer as a versatile, scalable platform for quantum communication protocols requiring fast, reconfigurable polarization-state measurements.
Comments7 pages, 4 pages, 1 table
