Review of Fiber Optic Displacement Sensors

Displacement Measurements Are of Significant Importance in a Variety of Critical Scientific and Engineering Fields, Such as Gravitational Wave Detection, Geophysical Research, and Manufacturing Industries. Due to the Inherent Advantages Such as Compactness, High Sensitivity, and Immunity to Electromagnetic Interference, in Recent Years, Fiber Optic Sensors Have Been Widely Used in an Expansive Range of Sensing Applications, Ranging from Infrastructural Health Monitoring to Chemical and Biological Sensing. of Particular Interest Here, Fiber Optic Displacement Sensors Have Gained Wide Interest and Have Evolved from Basic Intensity Modulation-Based Configurations to More Advanced Structures, Such as Fiber Bragg Grating (FBG)-Based and Interferometric Configurations. This Article Reviews Specifically the Advanced Fiber Optic Displacement Sensing Techniques that Have Been Developed in the Past Two Decades. Details Regarding the Working Principle, Sensor Design, and Performance Measures of FBG-Based, Interferometers-Based (Including the Fabry-Perot Interferometer, the Michelson Interferometer, and the Multimode Interferometer), Microwave Photonics-Based, and Surface Plasmon Resonance-Based Fiber Optic Displacement Sensors Are Given. Challenges and Perspectives on Future Research in the Development of Practical and High-Temperature Tolerant Displacement Sensors Are Also Discussed

Nuevos esquemas de sensores puntuales de fibra óptica para la detección simultánea de múltiples parámetros

90 p.Los sensores basados en fibra óptica han alcanzado una madurez en entornos industriales gracias a su mayor versatilidad y rendimiento frente a los sensores tradicionales, por lo que se han convertido en una alternativa viable y prometedora. Estos sensores tienen aplicaciones en sectores tan diversos como la salud, telecomunicaciones, seguridad, espaciales, aeronáuticas, entre otras, por lo tanto, los sensores de fibra óptica se han vuelto prácticamente indispensables para todas las ramas de la industria. De hecho, no hay área industrial que pueda prescindir de la medición, las pruebas, la supervisión o la automatización.En esta tesis se presenta como un compendio de artículos publicados. Su estructura consta de una primera sección de síntesis que incluye una introducción al tema de la investigación, la descripción del marco teórico y las herramientas metodológicas utilizadas para tal fin, la definición de la hipótesis y los objetivos que se persiguen. Así mismo un resumen y discusión de los resultados. En la segunda sección se presentan las conclusiones de la investigación realizada durante la tesis, así como las futuras líneas deinvestigación. Por último, en la tercera sección, se mencionan las contribuciones durante la tesis que incluyen una patente europea, trabajos presentados en congresos internacionales, tres artículos publicadosen revistas especializadas. Esto es lo que ha permitido presentar esta tesis como un compendio de artículos. La investigación descrita en esta tesis se divide en dos líneas, en ambas se explican en detalle el diseño, fabricación y prueba de cada sensor. En la primera, se explica el desarrollo de un sensor de índice de refracción con un gran rango de medición e independencia a la temperatura basado en un interferómetro Fabry Perot. Dicha investigación y sus resultados han dado lugar a una patente europea y a un artículo científico que se incluyen en el Artículo 1. En la segunda parte se describen dos sensores basados en fibras multi-núcleo fuertemente acopladas, MCF por sus siglas en inglés. Esta tecnología consiste en excitar y recombinar solo dos modos de luz en un segmento corto de fibra óptica MCF. El primer sensor es capaz de medir dos variables simultáneamente (temperatura e índice de refracción). El segundo sensor se basa en la inscripción de redes de Bragg en una fibra MCF, el cual tiene la capacidad de medir curvatura con independencia a la temperatura, con una aplicación en la monitorización de vibraciones (curvatura cíclica)

Micro-/Nano-Fiber Sensors and Optical Integration Devices

The development of micro/nanofiber sensors and associated integrated systems is a major project spanning photonics, engineering, and materials science, and has become a key academic research trend. During the development of miniature optical sensors, different materials and micro/nanostructures have been reasonably designed and functionalized on the ordinary single-mode optical fibers. The combination of various special optical fibers and new micro/nanomaterials has greatly improved the performance of the sensors. In terms of optical integration, micro/nanofibers play roles in independent and movable optical waveguide devices, and can be conveniently integrated into two-dimensional chips to realize the efficient transmission and information exchange of optical signals based on optical evanescent field coupling technology. In terms of systematic integration, the unique optical transmission mode of optical fiber has shown great potential in the array and networking of multiple sensor units.In this book, more than ten research papers were collected and studied, presenting research on optical micro/nanofiber devices and related integrated systems, covering high-performance optical micro/nanofiber sensors, fine characterization technologies for optical micro/nanostructures, weak signal detection technologies in photonic structures, as well as fiber-assisted highly integrated optical detection systems

Optical fibre based cantilever for sensing applications

The project investigated in this thesis is concerned with application of using optical fibre cantilever sensors for various applications where traditional electrical sensors cannot survive or work. These applications include micro-machined optical fibre-top cantilever sensor for high temperature and pH measurement, ferrule-top measurement to monitor real-time biomolecule binding process and optical fibre side cantilever sensor for acceleration measurement. In addition, a further investigation of optical fibre diaphragm sensor used for prostate stiffness measurement is also presented based on the same interrogation technique. First of all, interferometry to monitor the cantilever deflection will be investigated to avoid issues associated with intensity based systems while retaining high measurement resolution. Secondly, different manufacture techniques of cantilevers compatible with silica optical fibres (laser machining with ns/ps laser, FIB machining) is proposed for deflection measurement. This includes temperature/pH sensing, biological binding monitoring multicore fibres for multi-measurand sensors and optically activated sensors for acceleration measurements. The use of optical fibre offers a route to miniaturise sensor configuration to allow measurement of real-time bending of micro-cantilevers which can be transferred to cantilever surface energy change by Stoney’s equation. By investigating this small energy change, behaviour of real-time biomolecule binding can be monitored. A number of techniques and applications are investigated in the thesis

Hydrogen sensing using palladium coated long period gratings

The use of palladium coated optical fibres containing an in-fibre long period grating (LPG) structure for the sensing of low concentrations of hydrogen has been investigated. Previous proof of principle experiments were refined and extended, demonstrating sensitivities of up to 60 pm for 1% hydrogen at an operating temperature of 70°C. Characterisation of the Pd deposition technique (RF sputter coating) including XPS and SEM analysis to investigate surface roughness and contamination were carried out and are discussed. These measurements were prompted by the need to characterise and eliminate sensor drift associated with delamination of the sensor layer. Particular care was taken to characterise the optical properties of Pd thin films, both in the presence of hydrogen and without, through ellipsometry and surface plasmon resonance, since values gained from the literature showed wide variations. The results presented in this thesis differ from published Pd refractive indices but are specific for the conditions used in this work. Techniques to directly measure the refractive index profile within the core of an LPG were investigated and a possible solution is presented. Theoretical models to calculate the transmission spectrum of a LPG, both with and without a Pd layer are presented, discussed and the implications due to the poor characterisation of the LPG are considered. The potential use of higher order double cladding modes (with up to 20 times the sensitivity of the lower mode orders) as a sensing regime is investigated and the practical limitations discussed

Polymer Optical Fiber Sensors for Healthcare Devices: From the Material Analysis to Practical Applications

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New advances in vehicular technology and automotive engineering

An automobile was seen as a simple accessory of luxury in the early years of the past century. Therefore, it was an expensive asset which none of the common citizen could afford. It was necessary to pass a long period and waiting for Henry Ford to establish the first plants with the series fabrication. This new industrial paradigm makes easy to the common American to acquire an automobile, either for running away or for working purposes. Since that date, the automotive research grown exponentially to the levels observed in the actuality. Now, the automobiles are indispensable goods; saying with other words, the automobile is a first necessity article in a wide number of aspects of living: for workers to allow them to move from their homes into their workplaces, for transportation of students, for allowing the domestic women in their home tasks, for ambulances to carry people with decease to the hospitals, for transportation of materials, and so on, the list don’t ends. The new goal pursued by the automotive industry is to provide electric vehicles at low cost and with high reliability. This commitment is justified by the oil’s peak extraction on 50s of this century and also by the necessity to reduce the emissions of CO2 to the atmosphere, as well as to reduce the needs of this even more valuable natural resource. In order to achieve this task and to improve the regular cars based on oil, the automotive industry is even more concerned on doing applied research on technology and on fundamental research of new materials. The most important idea to retain from the previous introduction is to clarify the minds of the potential readers for the direct and indirect penetration of the vehicles and the vehicular industry in the today’s life. In this sequence of ideas, this book tries not only to fill a gap by presenting fresh subjects related to the vehicular technology and to the automotive engineering but to provide guidelines for future research. This book account with valuable contributions from worldwide experts of automotive’s field. The amount and type of contributions were judiciously selected to cover a broad range of research. The reader can found the most recent and cutting-edge sources of information divided in four major groups: electronics (power, communications, optics, batteries, alternators and sensors), mechanics (suspension control, torque converters, deformation analysis, structural monitoring), materials (nanotechnology, nanocomposites, lubrificants, biodegradable, composites, structural monitoring) and manufacturing (supply chains). We are sure that you will enjoy this book and will profit with the technical and scientific contents. To finish, we are thankful to all of those who contributed to this book and who made it possible.info:eu-repo/semantics/publishedVersio