The Raman optical time-domain reflectometry (ROTDR) uses the Raman backscattering signal of an optical pulse to obtain environmental information along the sensing fiber, with the pulse width limiting spatial resolution to the meter level in current systems. To solve this problem, we propose a chaos ROTDR system to eliminate the superposition effect of Raman backscattering response caused by pulse width. Here, the chaotic laser is applied as the sensing source instead of a conventional laser. For the random amplitude characteristics of the chaotic laser in time series, the chaotic Raman backscattering signal of individual points along the sensing fiber can be obtained, so that the millimeter level spatial resolution is realized. Firstly, the propagation equation of the chaotic Raman backscattering signal is established. Subsequently, the most relevant factors impacting the performance of spatial resolution and the signal-to-noise ratio (SNR) could be addressed based on two methods proposed in this study: one is the time-domain differential reconstruction (TDDR), and the other is the short-scale time-domain correlation compression (SSTDCC). Finally, the spatial resolution of 5 mm and temperature sensitivity of 0.1 K are achieved, which is an unprecedented breakthrough compared to the state-of-the-art technology.

中文翻译：

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用于毫米级空间分辨率温度传感的混沌拉曼光学时域反射法

拉曼光时域反射计 (ROTDR) 使用光脉冲的拉曼反向散射信号来获取沿传感光纤的环境信息，在当前系统中，脉冲宽度将空间分辨率限制为米级。为了解决这个问题，我们提出了一种混沌 ROTDR 系统来消除脉冲宽度引起的拉曼反向散射响应的叠加效应。在这里，混沌激光被用作传感源，而不是传统的激光。针对混沌激光器在时间序列上的随机幅度特性，可以获得沿传感光纤各点的混沌拉曼背向散射信号，从而实现毫米级空间分辨率。首先，建立了混沌拉曼背向散射信号的传播方程。随后，基于本研究中提出的两种方法，可以解决影响空间分辨率和信噪比 (SNR) 性能的最相关因素：一种是时域差分重建 (TDDR)，另一种是短尺度时域相关压缩 (SSTDCC)。最终实现了 5 mm 的空间分辨率和 0.1 K 的温度灵敏度，与最先进的技术相比，这是前所未有的突破。