The Fundamental Limit of Fiber-Optic Sensors in the Infrasonic Region

次声波区域光纤传感器的基本极限

• 批准号: 1606836
• 负责人: Lingze Duan
• 金额: $ 34.03万
• 依托单位: University of Alabama in Huntsville
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2021-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1606836&HistoricalAwards=false
• 关键词: Fundamental; Limit; Fiber; Optic; Sensors

Abstract Title: The Fundamental Limit of Fiber-Optic Sensors in the Infrasonic RegionNontechnical: Fiber-optic sensors have been widely used in industry and research. However, one of their fundamental properties, the intrinsic limit of sensitivity, has not been fully understood. Specifically, at infrasonic frequencies (below 20 Hz), there has been no direct observation of the inherent noise in fiber-optic sensors, and the available theories remain inconclusive. The proposed project aims to address this problem by devising a set of experiments to probe the sensitivity-limiting noise in optical fibers and supporting the experimental study with advanced theoretical modeling. By uncovering the physics underlying the ultimate limit of sensor performance at low frequencies, the research will substantially deepen the understanding of infrasonic fiber-optic sensing, allowing future sensor designers to exploit the full potential of fiber-optic sensors at an unprecedented level of sensitivity. Moreover, the novel sensor designs used in the experiments will serve as blueprints for future ultra-sensitive distributed infrasound sensors, which are critical for monitoring mass-destruction weapons, earthquakes, volcanic eruptions, glacial motions, etc. The project will directly fund multiple students at both undergraduate and graduate levels and will generate capstone and summer research opportunities for college and high school students. It will also help create a new research thrust, precision fiber-optic sensing, at the University of Alabama in Huntsville, and improve the presence of NSF in the state of Alabama.Technical: The overarching goal of the planned research is to understand the physics that sets the ultimate limit of fiber sensor sensitivity at low frequencies. The investigation will primarily focus on direct measurement of the spontaneous thermal noise generated by optical fibers in the infrasonic region. A parallel effort will also be dedicated to the development of a three-dimensional visco-elastic model with concentric structures to describe the thermomechanical noise in optical fibers. To address the challenges facing the measurement of the minuscule thermal noise at infrasonic frequencies, a new sensor design based on a Mach-Zehnder-Fabry-Perot hybrid interferometer will be employed. Preliminary theoretical analysis has shown that such a scheme is able to raise the sensor sensitivity by a factor of 104, hence extending the thermal noise-dominated spectral region to well below 1 Hz. The scientific merit of the proposed research rests upon its primary goal toward uncovering the fundamental physical law of fiber thermal noise. The mystery surrounding the 1/f behavior of fiber thermal noise has puzzled researchers for two decades. There is an urgent need within the fiber-optic sensor community for a thorough investigation specifically targeting the low-frequency characteristics of thermal noise. By leveraging new sensing concepts such as hybrid interferometers, the proposed work will completely transform optical sensing for low-frequency signals and open up a new paradigm of infrasonic technologies.

摘要标题：纤维电源传感器在基础区域非技术的基本限制：光纤传感器已被广泛用于行业和研究中。但是，他们的基本特性之一，即灵敏度的内在限制，尚未完全理解。具体而言，在不传动频率（低于20 Hz）下，没有直接观察光纤传感器中固有的噪声，并且可用的理论仍然尚无定论。拟议的项目旨在通过设计一组实验来探测光纤中的灵敏度限制噪声，并通过高级理论建模支持实验研究，以解决此问题。通过揭示在低频下传感器性能的最终限制的基础物理学，该研究将大大加深对互动光纤传感的理解，从而使未来的传感器设计者能够以前所未有的灵敏度水平利用光纤传感器的全部潜力。此外，实验中使用的新型传感器设计将作为未来超敏感的分布式式传感器的蓝图，这些传感器对于监视质量毁灭武器，地震，火山喷发，冰川动作等至关重要。该项目将直接在少年和研究生和夏季的研究中为多个学生提供资金，并为大学和夏季的学生提供资金。这还将有助于在阿拉巴马大学的阿拉巴马大学建立新的研究，精确的光纤传感，并改善NSF在阿拉巴马州的存在。技术研究：计划研究的总体目标是了解在低频率下纤维传感器敏感性的最终限制的物理学。该研究将主要集中于直接测量基外纤维产生的自发热噪声。并行的工作也将用于开发具有同心结构的三维粘弹性模型，以描述光纤中的热机械噪声。为了应对在频率下测量微小热噪声面临的挑战，将采用基于Mach-Zehnder-Fabry-Perot混合干涉仪的新传感器设计。初步理论分析表明，这种方案能够将传感器灵敏度提高104，从而将热噪声主导的光谱区域扩展到远低于1 Hz。拟议研究的科学优点取决于其主要目标，即揭示纤维热噪声的基本物理定律。围绕纤维热噪声1/F行为的奥秘使研究人员困惑了二十年。光纤传感器社区迫切需要进行彻底研究，专门针对热噪声的低频特征。通过利用新的传感概念，例如混合干涉仪，提出的工作将完全改变低频信号的光学感测，并打开新的Infrasonic Technologies的新范式。