Slope-assisted Brillouin optical time domain analysis (SA-BOTDA) is a fast and distributed sensing technique that interrogates the Brillouin gain spectrum (BGS) near the middle of the linear region of its slope, allowing the measurement of high frequency vibrations. However, environmentally-induced deviations of the interrogation point from the rather small linear region around the optimum frequency position, result in harmonic distortion and changes in the slope value, which determines the gain-to-frequency conversion factor. Engineering the BGS by adding a loss probe, we propose a novel and improved version of SA-BOTDA, having a significantly wider drift tolerance for the interrogation point. Here, using a 14 ns pump pulse and a judicious choice of the frequency of the loss probe, we demonstrate an engineered BGS having a 70% wider frequency range (as compared with the conventional BGS), where the interrogation point can drift without compromising either the prescribed level of harmonic distortion or the given slope tolerance, further benefiting the flexibility and usage of SA-BOTDA.

中文翻译：

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斜率辅助动态布里渊光时域分析中的增益谱工程

斜率辅助布里渊光时域分析 (SA-BOTDA) 是一种快速分布式传感技术，可查询其斜率线性区域中间附近的布里渊增益谱 (BGS)，从而测量高频振动。然而，询问点与最佳频率位置周围相当小的线性区域的环境引起的偏差会导致谐波失真和斜率值的变化，这决定了增益频率转换因子。通过添加损耗探针来设计 BGS，我们提出了一种新颖且改进的 SA-BOTDA 版本，对询问点具有明显更宽的漂移容限。在这里，使用 14 ns 泵浦脉冲和对损耗探头频率的明智选择，