AI 中文总结
该研究提出基于相同弱FBG的谐振频率映射技术，开发出高速、高稳定、高线性的实时准分布式光纤传感器，解决了传统DOFS的固有问题。
AI 中文摘要
基于拉曼、布里渊和瑞利散射的分布式光纤传感器（DOFS）近期在各类传感应用尤其是大规模监测领域受到广泛关注，原因在于其具备测量应变或温度分布的能力。然而，光纤内的极弱背向散射信号是DOFS不可避免的问题，这给整个系统带来了空间分辨率有限、测量速度低、系统复杂度高或成本高等负担。我们提出了一种新型谐振频率映射技术，用于基于相同弱光纤布拉格光栅（FBG）的实时准分布式光纤传感器，该传感器具有更强的反射信号和对多种传感参数的高灵敏度。谐振结构可在多次往返传播期间放大光信号，能简单高效地解决传统单往返测量中相同弱FBG传感器的固有问题，如串扰和光功率损耗。此外，对大量准分布式相同弱FBG进行单独测量在技术上是可行的，且具有相对较高的信噪比（SNR）、低串扰和低光功率损耗。通过映射谐振频率谱，可快速获取每个相同弱FBG的动态响应，速率达千赫兹量级，且无需耗时计算（如快速傅里叶变换（FFT））即可实现实时直接解调。该谐振频率谱基于全光纤电光结构获得，可同时以高速（>5 kHz）、高稳定性（约2.4微应变）和高线性度（R² = 0.9999）测量准分布式应变响应。
英文摘要
Distributed optical fiber sensors (DOFS) based on Raman, Brillouin, and Rayleigh scattering have recently attracted considerable attention for various sensing applications, especially large-scale monitoring, owing to their capacity for measuring strain or temperature distributions. However, ultraweak backscatter signals within optical fibers constitute an inevitable problem for DOFS, thereby increasing the burden on the entire system in terms of limited spatial resolution, low measurement speed, high system complexity, or high cost. We propose a novel resonance frequency mapping for a real-time quasi-distributed fiber optic sensor based on identical weak fiber Bragg gratings (FBG), which has stronger reflection signals and high sensitivity to multiple sensing parameters. The resonance configuration, which amplifies optical signals during multiple round-trip propagations, can simply and efficiently address the intrinsic problems in conventional single round-trip measurements for identical weak FBG sensors, such as crosstalk and optical power depletion. Moreover, it is technically feasible to perform individual measurements for a large number of quasi-distributed identical weak FBGs with relatively high signal-to-noise ratio (SNR), low crosstalk, and low optical power depletion. By mapping the resonance frequency spectrum, the dynamic response of each identical weak FBG is rapidly acquired in the order of kilohertz, and direct interrogation in real time is possible without time-consuming computation, such as fast Fourier transformation (FFT). This resonance frequency spectrum is obtained on the basis of an all-fiber electro-optic configuration that allows simultaneous measurement of quasi-distributed strain responses with high speed (>5 kHz), high stability (approximately 2.4 microstrain), and high linearity (R^2 = 0.9999).
Comments9 pages, 5 figures. Published in Scientific Reports. Supplementary information is available with the journal version
Journal refScientific Reports 9, 3921 (2019)
DOI：10.1038/s41598-019-40472-2
