Surpassing the detection limits of current distributed acoustic sensing systems (Conference Presentation)
Surpassing the detection limits of current distributed acoustic sensing systems (Conference Presentation)
复制标题
超越当前分布式声学传感系统的检测极限（会议演示）
DOI：
10.1117/12.2518716
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Donko A
中科院分区：
文献类型：
--
作者：
Donko A
分布式声传感器(DAS)系统的探测范围受信号衰减的限制，约为75公里。对于对海底电缆结构健康监测感兴趣的海上风电场运营商来说，增加检测范围的能力具有巨大的商业利益。在大多数情况下，运营商感兴趣的是监测200公里~400公里的海底光缆，在光缆的两端可以接触到光纤。在本文中，我们提出了一种新的、商业上可行的超低损耗传感元件，它由离散的宽带反射器组成。在100米的光纤样品上进行了光学时域反射仪测量。样品包含以3m为间隔放置的反射器。在反射器位置，记录的踪迹显示后向散射信号增加了200倍于纤维的未修改区域。从理论上讲，使用这种新元件的系统的空间分辨率仅受分辨两个反射点的能力的限制。因此，只要采用足够的数据采集和处理技术，超低损耗光纤也为远距离高空间分辨率测量提供了可能性。显著的增强意味着不需要放大反射信号，从而进一步降低了系统的成本。为了验证光纤的长距离能力，对样品进行了光学侧面散射辐射测量。从一个反射点产生的最大侧向散射损耗为每个反射点10^-4分贝。如果每米放置一个反射器，则总光纤衰减预计为每公里0.3分贝。
The detection range of Distributed Acoustic Sensor (DAS) systems is limited by signal attenuation to approximately 75 km. The ability to increase the detection range is of great commercial interest to the offshore wind farm operators interested in structural health monitoring of their subsea cables. In most cases, the operators are interested in monitoring 200km~400km subsea cable where the fibres can be accessed at two ends of the cable. In this paper, we present a new, commercially viable, ultra low-loss sensing element, comprising of discrete broadband reflectors. Optical time domain reflectometry measurements were performed on a 100 m sample of the fibre. The sample contained reflectors placed at 3 m intervals. At reflector sites, the recorded trace revealed increases in the backscatter signal two hundred times that of the unmodified regions of the fibre. Theoretically, the spatial resolution of a system utilising this new element is only restricted by the ability to resolve two reflector points. Therefore, the ultra low loss fibre also offers the potential for high spatial resolution measurements over large distances, as long as sufficient data acquisition and processing techniques are employed. The significant enhancement means no amplification of the reflected signal is required, further reducing the cost of the system. To verify the long distance capability of the fibre, the sample was subjected to optical side scattering radiometry measurements. The largest side-scattered loss from a reflector point was 10^-4 dB per reflector. If a reflector was placed every meter, the total fibre attenuation is predicted to be 0.3 dB per km.