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arXiv 2407.08009quant-ph
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长光纤萨格纳克干涉仪用于双场量子密钥分发网络

Long-fiber Sagnac interferometers for twin field quantum key distribution networks

Reem Mandil, Li Qian, Hoi-Kwong Lo

AI总结:

本研究提出利用长通断突发光脉冲与时间后选择,克服萨格纳克环中瑞利噪声,实现200公里超低损耗光纤上>97%干涉可见度,验证了长距离TFQKD网络的可行性。

摘要:

萨格纳克环结构有助于克服双场量子密钥分发(TFQKD)网络实际实施中的主要困难,即需要在数公里光纤上稳定量子态的相位。不幸的是,瑞利背向散射噪声限制了包含长光纤和有损光子器件的萨格纳克系统的信噪比。在这里,我们通过以长通断突发方式发送光脉冲,并对自由运行的单光子雪崩探测器所进行的测量采用时间后选择来解决这一问题。我们还研究了萨格纳克结构未补偿的残余相位噪声的影响,发现相位噪声的方差随环长度的三次方缩放,验证了文献中已有的计算结果。我们在没有主动相位稳定的情况下测量了不同长度萨格纳克环的干涉可见度,并在200公里超低损耗光纤中实现了>97%的可见度,据我们所知,这是迄今演示的最长光纤萨格纳克干涉仪。我们的结果表明,萨格纳克系统对于长距离TFQKD网络是可行的,这是朝着城域量子网络实际实施迈出的重要一步。

英文摘要:

A Sagnac loop structure can help overcome the major difficulty in the practical implementation of a twin field quantum key distribution (TFQKD) network, namely, the need to stabilize the phase of a quantum state over many kilometers of fiber. Unfortunately, Rayleigh backscattering noise limits the signal-to-noise ratio for Sagnac systems containing long fibers and lossy photonic devices. Here, we solve this problem by sending optical pulses in long on-off bursts and using time post-selection on measurements taken with free-run single-photon avalanche detectors. We also investigate the impact of the residual phase noise uncompensated by the Sagnac structure and find that the variance of the phase noise scales as loop length to the third power, verifying an existing calculation in the literature. We measure the interference visibility in Sagnac loops of varying length without active phase stabilization and achieve > 97% visibility in 200 km ultra-low-loss fiber, which is, to our knowledge, the longest fiber Sagnac interferometer demonstrated. Our results suggest that a Sagnac system is feasible for long-distance TFQKD networks, an important step towards the practical implementation of metropolitan quantum networks.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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