High-Resolution Distributed Acoustic Sensor and its Applications in Mechanical Engineering

The past decade has witnessed rapid adoption of distributed acoustic sensor (DAS) technology in various fields from geophysical sciences [1] to railway track behaviour analysis [2]. Limited by the intensity of the Rayleigh backscattering, DAS technology has been mainly adopted for mapping phenomena such as earthquakes or rail traffic that do not require high spatial resolution. Recently, we have developed a new optical fibre that allows an order of magnitude improvement in the spatial resolution of DAS systems. Using this fibre, which we dubbed Ultra Low-loss Enhanced Backreflection (ULEB) fibre, we have demonstrated a DAS with 10 cm spatial resolution and an amplitude spectral density of $1.9 mathrm{n}varepsilon/surd ext{Hz}$ [3].

过去十年见证了分布式声学传感器（DAS）技术在从地球物理科学[1]到铁路轨道行为分析[2]等各个领域的迅速应用。受瑞利后向散射强度的限制，DAS技术主要被用于绘制诸如地震或轨道交通等不需要高空间分辨率的现象。最近，我们开发了一种新的光纤，它使DAS系统的空间分辨率提高了一个数量级。使用这种我们称之为超低损耗增强后向反射（ULEB）光纤，我们已经展示了一种具有10厘米空间分辨率和$1.9\mathrm{n}\varepsilon /\sqrt{\text{Hz}}$振幅谱密度的DAS[3]。