标题： 无内联放大时间传输利用波形分辨单光子检测 显示英文标题

标题： Inline-Amplification-Free Time Transfer Utilizing Waveform-Resolved Single-Photon Detection

摘要： 高精度的长距离光纤时间传递在许多领域中起着重要作用。 核心方法，即通过级联中继节点来补偿信号衰减和色散，然而对于关键的点对点传输场景，例如基础设施极度匮乏的恶劣环境和紧急情况，该方法是不够的。 在没有任何中继放大器的远距离信号传输中，光纤链路的高损耗成为主要限制因素，而在接收端直接使用传统光电探测器会导致检测信号的稳定性显著下降。 在这里，我们提出了一种波形分辨的单光子探测技术，并对平均光子数仅为每脉冲0.617的弱传输信号进行了实验性层析成像。 通过采用这种技术，我们在平均时间为1秒时，在200公里和300公里处分别实现了95.68皮秒和192.58皮秒的时间偏差，克服了由传统光电探测器引起的技朮下限。 这项工作为在那些重要的无中继放大场景中实现高精度的透传时间传递奠定了基础。 显示英文摘要

摘要： High-precision time transfer over a long haul of fiber plays a significant role in many fields. The core method, namely cascading relay nodes for the compensation of signal attenuation and dispersion, is however insufficient to deal with crucial point-to-point transfer scenarios, such as harsh environments with extremely deficient infrastructure and emergency conditions. In long-distance signal transmission without any inline amplifiers, the high loss of the optical fiber link becomes the primary limiting factor, and direct use of traditional photodetectors at the receiving end will bring about a significant drop in the stability of detected signals. Here we propose a waveform-resolved single photon detection technique and experimentally perform tomography on the weak transferred signal with an average photon number of just 0.617 per pulse. By adopting this technique, we achieve the time deviation of 95.68 ps and 192.58 ps at 200 km and 300 km respectively at an averaging time of 1 s, overcoming the technical lower bound induced by traditional photodetectors. This work lays the foundation for through-type time transfer with high precision in those significant inline-amplification-free scenarios.