Download or read book Analysis and Modelling of a Novel Approach for the Interrogation Unit of Fiber Bragg Grating Sensors Using Optical Frequency Domain Reflectometry Techniques written by Deniz Pala and published by . This book was released on 2014 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main purpose of this thesis is to demonstrate the feasibility of using polarization properties of FBGs interrogated by OFDR for quasi-distributed sensing applications. A fiber Bragg grating (FBG) is a constant and periodic refractive index value modulation within the core along an optical fiber. This modification is generally obtained by exposing the fiber core of a photosensitive optical fiber to an intense ultraviolet (UV) interference pattern. At the fabrication process of Bragg gratings, only one side of the fiber expose to UV light. As a result, refractive index change is not constant at the cross section of fiber. This non-uniformity on the refractive index gives rise to photo-induced birefringence which combines with the birefringence resulting from the slightly elliptical shape of the optical fiber and creates a global birefringence value. In the presence of the birefringence, the reflection (transmission) spectrum of Bragg grating is degenerated into two reflection (transmission) spectra corresponding to a pair of orthogonal polarization modes (x and y modes). The ratio between maximum and minimum optical transmitted power of these modes are defined as Polarization Dependent Loss (PDL). We analyzed the reflection spectrum, transmission spectrum and the PDL of the cascaded FBGs interrogated by an OFDR by the way of simulations. Based on the simulation results, we demonstrated the feasibility of a novel FBG interrogation method which can be implemented in quasi-distributed strain sensors embedded into composite materials.
Download or read book Fiber Bragg Grating Based Sensors and Systems written by Oleg Morozov and published by MDPI. This book was released on 2021-08-18 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a collection of papers that originated as a Special Issue, focused on some recent advances related to fiber Bragg grating-based sensors and systems. Conventionally, this book can be divided into three parts: intelligent systems, new types of sensors, and original interrogators. The intelligent systems presented include evaluation of strain transition properties between cast-in FBGs and cast aluminum during uniaxial straining, multi-point strain measurements on a containment vessel, damage detection methods based on long-gauge FBG for highway bridges, evaluation of a coupled sequential approach for rotorcraft landing simulation, wearable hand modules and real-time tracking algorithms for measuring finger joint angles of different hand sizes, and glaze icing detection of 110 kV composite insulators. New types of sensors are reflected in multi-addressed fiber Bragg structures for microwave–photonic sensor systems, its applications in load-sensing wheel hub bearings, and more complex influence in problems of generation of vortex optical beams based on chiral fiber-optic periodic structures. Original interrogators include research in optical designs with curved detectors for FBG interrogation monitors; demonstration of a filterless, multi-point, and temperature-independent FBG dynamical demodulator using pulse-width modulation; and dual wavelength differential detection of FBG sensors with a pulsed DFB laser.
Download or read book Design and Fabrication of an Optical Fiber Interrogation Instrumentation System written by Srirajasingam Vahesan and published by . This book was released on 2006 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Novel Methods for Interrogation of Fiber Bragg Gratings and Their Applications for Developing New Optical Sensors written by Shay Keren and published by . This book was released on 2003 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fiber Bragg Grating Sensors written by Oleg G Morozov and published by . This book was released on 2024-07-16 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This reprint aims to explore one of the most popular trends of relevance to sensors, which represents an influential platform for the exchange of scientific knowledge in the field of FBGs from the point of view of its recent advances and future perspectives. We are opening small, but very interesting pages in FBGs' 35-year history. The first section is devoted to the modernization of FBG basics and its performance in various conditions: line-by-line inscription of tilted FBGs, radiation effects on FBGs, and short-term creep effect on strain transfer from fiber-reinforced polymer strips. The second one details new approaches to interrogation methods: a detailed algorithm of FBG spectrum distortion correction for classical OSA with CCD elements and noise analysis of new microwave photonic interrogation of fiber-based sensors. The next section reflects the results of using FBGs in aviation systems: noise cancellation of helicopter blade deformations, design of a high-precision shape sensor for wing shape reconstruction, and development of a medium-frequency accelerometer based on flexible hinges. We separately discuss the transfer of FBG technologies to new devices based on integral photonics and new mediums in which FBGs can gain new life: modeling a fully integrated micro-ring-based photonic system for liquid refractometry and designing wavelength-tunable vortex beam emitters based on silicon micro-rings and twisted few-mode optical fibers with improved height of quasi-step refractive index profiles.
Download or read book Fiber Bragg Gratings written by Raman Kashyap and published by Academic Press. This book was released on 1999-03 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt: Forward. Preface. Introduction. Photosensitivity and Photosensitization of Optical Fibers. Fabrication of Bragg Gratings. Theory of Fiber Bragg Gratings. Apodisation of Fiber Gratings. Fiber Grating Band-Pass Filters. Chirped Fiber Bragg Gratings. Fiber Grating Lasers and Amplifiers. Measurement and Characterization of Gratings. Index.
Download or read book Fiber Bragg Grating Sensors Recent Advancements Industrial Applications and Market Exploitation written by Andrea Cusano and published by Bentham Science Publishers. This book was released on 2011 with total page 331 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is an exciting source of information for individuals interested in learning about and marketing sensors. The book focuses on scientific and commercial advances in Fiber Bragg Grating (FBG) sensor technology since its discovery over 30 years ago.
Download or read book Fiber Bragg Grating Interrogation Systems written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis work deals with the development of three different categories of interrogation techniques for Fiber Bragg Grating based sensor networks. Such networks are used for structural health monitoring and other applications. A bulk grating based interrogation system is described first, which includes an optical source, switch, circulator, embedded controller, and software. The center wavelength determination technique employed is detailed and is shown to be highly accurate from test data. The comparison with resistance strain gauges is presented which shows that the system developed provides an accurate strain reconstruction. The system is also compared with a commercial optical spectrum analyzer and is found to exhibit good accuracy and fidelity. The system has been field tested on an aircraft structure with 14 sensors spread over 4 channels. Strain data reconstruction from these tests is shown to accurately reproduce the loading conditions. A second system developed is based on the matched filter technique using a mechanical fiber stretcher; the details of this system are presented with a mathematical treatment of the technique. The design of the fiber stretcher is also described. This design is regarded to be novel since it tries to provide large interrogation bandwidths using a parallel topology. The results of tests have shown good resolution and comparative tests with resistance strain gauges have shown accurate reproduction of strain. Finally, an interrogation system based on a wavelength tunable source is presented. This system is a precursor to a time division multiplexed interrogation system, which has also been described. Three laser configurations have been set up and characterized. The laser sweep tests have been performed on two configurations and a sensor grating reconstruction test has also been carried out.
Download or read book Fiber Bragg Grating Based Sensors and Systems written by Oleg Morozov and published by . This book was released on 2021 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a collection of papers that originated as a Special Issue, focused on some recent advances related to fiber Bragg grating-based sensors and systems. Conventionally, this book can be divided into three parts: intelligent systems, new types of sensors, and original interrogators. The intelligent systems presented include evaluation of strain transition properties between cast-in FBGs and cast aluminum during uniaxial straining, multi-point strain measurements on a containment vessel, damage detection methods based on long-gauge FBG for highway bridges, evaluation of a coupled sequential approach for rotorcraft landing simulation, wearable hand modules and real-time tracking algorithms for measuring finger joint angles of different hand sizes, and glaze icing detection of 110 kV composite insulators. New types of sensors are reflected in multi-addressed fiber Bragg structures for microwave-photonic sensor systems, its applications in load-sensing wheel hub bearings, and more complex influence in problems of generation of vortex optical beams based on chiral fiber-optic periodic structures. Original interrogators include research in optical designs with curved detectors for FBG interrogation monitors; demonstration of a filterless, multi-point, and temperature-independent FBG dynamical demodulator using pulse-width modulation; and dual wavelength differential detection of FBG sensors with a pulsed DFB laser.
Download or read book Fiber Bragg Grating Sensors Development and Applications written by Hisham Hisham and published by CRC Press. This book was released on 2019-06-19 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the basic principles of optical sensor technology in line with the tremendous development in the concept of optical fibers. In the first four chapters, the book discusses the basic principles of optical sensor technology in a simplified manner, making it suitable for all levels of study and research. The seven remaining chapters are concerned with the practical applications of optical sensor technology in all fields such as oil and gas, civil engineering, medical and military fields and harsh environments.
Download or read book Fiber Bragg Gratings written by Marcelo Martins Werneck and published by SPIE-International Society for Optical Engineering. This book was released on 2017 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This Tutorial Text delivers essential information concerning fiber Bragg gratings to professionals and researchers with an approach based on rules of thumb and practical aspects, enabling quick access to the main principles and techniques, and allowing readers to set up their own laboratory or application. It provides detailed information about how to operate and use these novel sensors, particularly with respect to the required infrastructure, daily operation, and possible applications. After a discussion of the primary concepts, practical aspects regarding the development of a FBG laboratory and how these components are manufactured and used in practical applications are presented. The following chapters outline the operation of Bragg gratings and, for instance, discuss how measurement information can be retrieved (interrogation techniques), calibration methods, and how to prepare and deploy the devices in real monitoring conditions. The final chapters present several successful, real-world applications of the technology"--
Download or read book Interrogation system of fiber bragg grating sensors using time division multiplexing and waveleght division multiplexing written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Um sistema de interrogação de sensores a rede de Bragg utilizando multiplexação no tempo e multiplexação no comprimento de onda é proposto e demonstrado. O sistema apresenta uma solução para a medição de grandezas associadas ao espectro de reflexão de redes de Bragg, possibilitando o aumento do número de sensores a rede de Bragg monitorados através de grandes distâncias em uma mesma fibra óptica, sem um aumento significativo dos custos. O aspecto inovador deste sistema reside na particular associação das seguintes características: o uso de fonte pulsada de banda larga, a disposição, em série, de um grande número de sensores a rede de Bragg de baixa refletividade, a técnica de reutilização dos mesmos comprimentos de onda nominais em grupos contendo vários sensores com comprimentos de onda nominais distintos e um processo de filtragem espectral e análise de sinais pulsados utilizando o filtro DWDM comercial. Aspectos teóricos e experimentais considerando os princípios de trabalho desta técnica são discutidos. Comparações entre resultados simulados e experimentais do sistema implantado mostram boa concordância. Resultados experimentais apontam uma faixa dinâmica de 1,7 nm, podendo encontrar aplicações em medição de temperatura com uma faixa de 150°C. Incertezas com valores médios abaixo de 20 picometros foram obtidas. Simulações experimentais apontam a possibilidade de utilização de um número de aproximadamente 70 sensores com 0,4% de refletividade, por comprimento de onda. Considerando a largura de banda do dispositivo DWDM (1539-1565 nm) utilizado neste sistema, e um espaçamento de 7 nm por comprimento de onda nominal de sensor, extrapolações mostram que este número pode chegar a 210 sensores em três diferentes comprimentos de onda nominais de sensor. Considerando as bandas C e L este número pode chegar a aproximadamente 1000 sensores em 14 diferentes comprimentos de onda nominais de sensor.
Download or read book Fibre Bragg Grating and No Core Fibre Sensors written by Suzairi Daud and published by Springer. This book was released on 2018-04-23 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the development and set-up of fibre Bragg grating (FBG) and no-core fibre (NCF) sensors. It discusses the properties of the sensors and modelling of the resulting devices, which include electronic, optoelectronic, photovoltaic, and spintronic devices. In addition to providing detailed explanations of the properties of FBG and NCF sensors, it features a wealth of instructive illustrations and tables, helping to visualize the respective devices’ functions.
Download or read book Tilted Fibre Bragg Grating Sensors with Resonant Nano scale Coatings written by Aliaksandr Bialiayeu and published by . This book was released on 2015-03-20 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: Doctoral Thesis / Dissertation from the year 2014 in the subject Physics - Optics, language: English, abstract: Fibre Bragg grating sensors have emerged as a simple, inexpensive, accurate, sensitive and reliable platform, a viable alternative to the traditional bulkier optical sensor platforms. In this work we present an extensive theoretical analysis of the tilted fibre Bragg grating sensor (TFBG) with a particular focus on its polarization-dependent properties. We have developed a highly efficient computer model capable of providing the full characterization of the TFBG device in less then $3$ minutes for a given state of incident light polarization. As a result, the polarization-dependent spectral response, the field distribution at the sensor surface as well as the fine structure of particular resonances have become accessible for theoretical analysis. As a part of this computer model we have developed a blazingly fast full-vector complex mode solver, capable of handling cylindrical waveguides of an arbitrary complex refractive index profile. Along with the theoretical study we have investigated optical properties of the TFBG sensor with application to polarisation-resolved sensing. We proposed a new method of the TFBG data analysis based on tracking the grating transmission spectra along its principle axes, which were extracted from the Jones matrix. In this work we also propose a new method of enhancing the TFBG sensor refractometric sensitivity limits, based on resonant coupling between the TFBG structure resonances and the local resonances of nanoparticles deposited on the sensor surface. The $3.5$-fold increase in the TFBG sensor sensitivity was observed experimentally.
Download or read book Optical Frequency Domain Reflectometry for High Density Multiplexing of Multi Axis Fiber Bragg Gratings written by and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: An interferometric fiber grating interrogation system utilizing a depolarized Erbium ring laser was used to interrogate transversely strained gratings written through the polyimide coating with 1 mm spatial resolution, and the interferometric results were compared to waveforms taken using a broadband source and OSA.
Download or read book A Technology Assessment of Bragg Grating Fiber Optic Based Nondestructive Evaluation NDE written by H. Thomas Yolken and published by . This book was released on 2001 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Free Spectral Range Matched Interrogation Technique for Wavelength Demodulation of Fiber Bragg Grating Sensors written by Somayyeh Rahimi and published by . This book was released on 2009 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Free Spectral Range Matched Interrogation (FSRMI) technique for wavelength demodulation of fiber Bragg grating sensors. We designed and tested a new wavelength demodulation system based on free-spectral-range-matched interrogation which employs a tunable fiber Fabry-Perot interferometer (FPI) and a multi-channel bandpass filter. This technique was deployed to test fiber Bragg gratings (FBG), long period gratings (LPG) and tilted fiber Bragg gratings (TFBG). In the experimental setup, a broadband source launches light into a fiber Bragg grating under test and the reflection/transmission spectrum is fed into a tunable FPI. By tuning an external bias applied to the FPI, the transmission spectrum of FPI scans over a wavelength range. The input optical signal is therefore selectively passed through the FPI and then fed into a four-channel bandpass filter followed by four photodetectors. The optical signal is converted to electrical signal by the photodiodes and is acquired by a data acquisition system. Since a bandpass filter with four channels are used in this interrogation system it can scan four distinguished wavelength ranges simultaneously and thus the scan rate is four time faster. We used this setup for doing some temperature and strain sensitivity measurements on some fiber gratings. Strain sensitivity measurements were done on FBG, TFBG and LPG and temperature sensitivity measurements were performed on TFBG. The strain and temperature sensitivity coefficients of these fiber Bragg grating sensors were obtained from experimental data. Our results show the potential of the integration of the FSRMI system with fiber Bragg gratings for temperature and strain multiple-sensor arrays with high sampling speed and high accuracy.
