WorldWideScience

Sample records for fiber optic sensing

  1. Optical fiber rotation sensing

    CERN Document Server

    Burns, William K; Kelley, Paul

    1993-01-01

    Optical Fiber Rotation Sensing is the first book devoted to Interferometric Fiber Optic Gyros (IFOG). This book provides a complete overview of IFOGs, beginning with a historical review of IFOG development and including a fundamental exposition of basic principles, a discussion of devices and components, and concluding with industry reports on state-of-the-art activity. With several chapters contributed by principal developers of this solid-state device, the result is an authoritative work which will serve as the resource for researchers, students, and users of IFOGs.* * State-of-t

  2. Fiber optic sensing and imaging

    CERN Document Server

    2013-01-01

    This book is designed to highlight the basic principles of fiber optic imaging and sensing devices. The editor has organized the book to provide the reader with a solid foundation in fiber optic imaging and sensing devices. It begins with an introductory chapter that starts from Maxwell’s equations and ends with the derivation of the basic optical fiber characteristic equations and solutions (i.e. fiber modes). Chapter 2 reviews most common fiber optic interferometric devices and Chapter 3 discusses the basics of fiber optic imagers with emphasis on fiber optic confocal microscope. The fiber optic interferometric sensors are discussed in detail in chapter 4 and 5. Chapter 6 covers optical coherence tomography and goes into the details of signal processing and systems level approach of the real-time OCT implementation. Also useful forms of device characteristic equations are provided so that this book can be used as a reference for scientists and engineers in the optics and related fields.

  3. Fiber Optic Sensing: Prototype Results

    Science.gov (United States)

    Ortiz Martin, Jesus; Gonzalez Torres, Jose

    2015-09-01

    Airbus DS Crisa has been developing an interrogator of Fiber Bragg Grating sensors [1], aimed at measuring, mainly, temperature and strain by means of fiber optic links. This activity, funded by Airbus DS Crisa, ESA and HBM Fibersensing, finalizes with the manufacturing of a prototype. The present paper describes in detail the main outcomes of the testing activities of this prototype. At the moment of writing the paper all the functional tests have been concluded. The environmental tests, thermal and mechanical, will be conducted with the FOS interrogator forming part of the RTU2015, described in [2].

  4. Ultra Small Integrated Optical Fiber Sensing System

    Directory of Open Access Journals (Sweden)

    Peter Van Daele

    2012-09-01

    Full Text Available This paper introduces a revolutionary way to interrogate optical fiber sensors based on fiber Bragg gratings (FBGs and to integrate the necessary driving optoelectronic components with the sensor elements. Low-cost optoelectronic chips are used to interrogate the optical fibers, creating a portable dynamic sensing system as an alternative for the traditionally bulky and expensive fiber sensor interrogation units. The possibility to embed these laser and detector chips is demonstrated resulting in an ultra thin flexible optoelectronic package of only 40 ?m, provided with an integrated planar fiber pigtail. The result is a fully embedded flexible sensing system with a thickness of only 1 mm, based on a single Vertical-Cavity Surface-Emitting Laser (VCSEL, fiber sensor and photodetector chip. Temperature, strain and electrodynamic shaking tests have been performed on our system, not limited to static read-out measurements but dynamically reconstructing full spectral information datasets.

  5. Industrial applications of fiber optic sensing

    Science.gov (United States)

    Desforges, Francois X.; Blocksidge, Robert

    1996-08-01

    Thanks to the growth of the fiber optics telecommunication industry, fiber optic components have become less expensive, more reliable and well known by potential fiber optic sensor users. LEDs, optical fibers, couplers and connectors are now widely distributed and are the building blocks for the fiber optic sensor manufacturer. Additionally, the huge demand in consumer electronics of the past 10 years has provided the manufacturer with cheap and powerful programmable logic components which reduce the development time as well as the cost of the associated instrumentation. This market trend has allowed Photonetics to develop, manufacture and sell fiber optic sensors for the last 10 years. The company contribution in the fields of fiber optic gyros (4 licenses sold world wide), white light interferometry and fiber optic sensor networks is widely recognized. Moreover, its 1992 acquisition of some of the assets of Metricor Inc., greatly reinforced its position and allowed it to pursue new markets. Over the past four years, Photonetics has done an important marketing effort to better understand the need of its customers. The result of this research has fed R&D efforts towards a new generation instrument, the Metricor 2000, better adapted to the expectations of fiber optic sensors users, thanks to its unique features: (1) universality -- the system can accept more than 20 different sensors (T, P, RI, . . .). (2) scalability -- depending on the customer needs, the system can be used with 1 to 64 sensors. (3) performance -- because of its improved design, overall accuracies of 0.01% FS can be reached. (4) versatility -- its modular design enables a fast and easy custom design for specific applications. This paper presents briefly the Metricor 2000 and its family of FO probes. Then, it describes two fiber optic sensing (FOS) applications/markets where FOS have proven to be very useful.

  6. Optical Fiber Sensing Using Quantum Dots

    Directory of Open Access Journals (Sweden)

    Faramarz Farahi

    2007-12-01

    Full Text Available Recent advances in the application of semiconductor nanocrystals, or quantumdots, as biochemical sensors are reviewed. Quantum dots have unique optical properties thatmake them promising alternatives to traditional dyes in many luminescence basedbioanalytical techniques. An overview of the more relevant progresses in the application ofquantum dots as biochemical probes is addressed. Special focus will be given toconfigurations where the sensing dots are incorporated in solid membranes and immobilizedin optical fibers or planar waveguide platforms.

  7. Fiber optic nanoprobes for biological sensing

    Science.gov (United States)

    Barucci, Andrea; Berneschi, Simone; Cosi, Franco; Nunzi Conti, Gualtiero; Pelli, Stefano; Quercioli, Franco; Soria, Silvia; Righini, Giancarlo C.

    2011-08-01

    Optical sensors have a large impact in the fields of life science research, drug discovery and medical diagnostics. The recent advances in nanotechnology and photonics have led to a new generation of nanotools, capable of probing even the single cell: it has already been demonstrated that nanobiosensors can detect biochemical targets and proteins inside living single cells. Here we provide a brief overview of the field of nanoprobes consisting of tapered, metal-coated optical fibers having nanosize tips, such as those which were originally developed for use in near-field optical microscopy. Moreover we present some preliminary results concerning the characterization of the experimental sensing system which exploits such nanoprobes for intracellular biomedical diagnostics. The feasibility of using the Fluorescence Lifetime Imaging Microscopy (FLIM) technique as a dynamic diagnostics tool with these nanoprobes has been demonstrated.

  8. Bridge SHM system based on fiber optical sensing technology

    Science.gov (United States)

    Li, Sheng; Fan, Dian; Fu, Jiang-hua; Huang, Xing; Jiang, De-sheng

    2015-09-01

    The latest progress of our lab in recent 10 years on the area of bridge structural health monitoring (SHM) based on optical fiber sensing technology is introduced. Firstly, in the part of sensing technology, optical fiber force test-ring, optical fiber vibration sensor, optical fiber smart cable, optical fiber prestressing loss monitoring method and optical fiber continuous curve mode inspection system are developed, which not only rich the sensor types, but also provides new monitoring means that are needed for the bridge health monitoring system. Secondly, in the optical fiber sensing network and computer system platform, the monitoring system architecture model is designed to effectively meet the integration scale and effect requirement of engineering application, especially the bridge expert system proposed integration of sensing information and informatization manual inspection to realize the mode of multi index intelligence and practical monitoring, diagnosis and evaluation. Finally, the Jingyue bridge monitoring system as the representative, the research on the technology of engineering applications are given.

  9. Fiber optic structures for dynamic stress sensing

    Science.gov (United States)

    Plaga, Robert; Lesiak, Piotr; Woli?ski, Tomasz R.

    2011-10-01

    The paper presents influence of the HB1500 bow-tie optical fiber coating on the fiber angular sensitivity for dynamic stress induced by an acoustic wave. An experimental setup is explained and fiber parameters are presented, what is a step forward to predict and simulate behavior of optical fibers embedded in composite materials. Both sensitivities of the fiber (with and without coating) are compared versus the angle between the birefringence axis and the acoustic wave propagation direction. An influence of the fiber coating has also been experimentally examined.

  10. Advanced fiber optical chemical sensing networks

    International Nuclear Information System (INIS)

    Many industrial processes or other phenomena of interest cannot be measured with conventional instruments because they are too hot, too cold, highly radioactive, or otherwise inaccessible to direct observation. Nuclear wastes stored in underground repositories, for example, will require in-situ monitoring. A new technology that uses long-distance fiber optics to transmit laser-excited fluorescence now makes it possible to remotely monitor such phenomena via optical cables at distances up to a kilometer. The basic system consists of a laser light source, a Raman-fluorescence scattering spectrometer, and an optical fiber linked to a measuring device at the other end. Laser-generated light passes through an aperture and is focused on the end of the optical fiber by a geometric beam splitter. The light passes through the fiber, interacts with the sample to be measured, and returns (now incoherent), where it is reflected by a mirror into the computerized spectrometer for analysis

  11. Extruded single ring hollow core optical fibers for Raman sensing

    Science.gov (United States)

    Tsiminis, G.; Rowland, K. J.; Ebendorff-Heidepriem, H.; Spooner, N. A.; Monro, T. M.

    2014-05-01

    In this work we report the fabrication of the first extruded hollow core optical fiber with a single ring of cladding holes. A lead-silicate glass billet is used to produce a preform through glass extrusion to create a larger-scale version of the final structure that is subsequently drawn to an optical fiber. The simple single suspended ring structure allows antiresonance reflection guiding. The resulting fibers were used to perform Raman sensing of liquid samples filling the length of the fiber, demonstrating its potential for fiber sensing applications.

  12. Fiber-Optic Sensing for In-Space Inspection

    Science.gov (United States)

    Pena, Francisco; Richards, W. Lance; Piazza, Anthony; Parker, Allen R.; Hudson, Larry D.

    2014-01-01

    This presentation provides examples of fiber optic sensing technology development activities performed at NASA Armstrong. Examples of current and previous work that support in-space inspection techniques and methodologies are highlighted.

  13. Optical Fiber Sensing Based on Reflection Laser Spectroscopy

    Directory of Open Access Journals (Sweden)

    Gianluca Gagliardi

    2010-03-01

    Full Text Available An overview on high-resolution and fast interrogation of optical-fiber sensors relying on laser reflection spectroscopy is given. Fiber Bragg-gratings (FBGs and FBG resonators built in fibers of different types are used for strain, temperature and acceleration measurements using heterodyne-detection and optical frequency-locking techniques. Silica fiber-ring cavities are used for chemical sensing based on evanescent-wave spectroscopy. Various arrangements for signal recovery and noise reduction, as an extension of most typical spectroscopic techniques, are illustrated and results on detection performances are presented.

  14. RF modulated fiber optic sensing systems and their applications

    Science.gov (United States)

    Adamovsky, G.; Eustace, J. G.

    1993-01-01

    A fiber optic sensing system with an intensity sensor and a Radio Frequency (RF) modulated source was shown to have sensitivity and resolution much higher than a comparable system employing low modulating frequencies or DC mode of operation. Also the RF modulation with an appropriate configuration of the sensing system provides compensation for the unwanted intensity losses. The basic principles and applications of a fiber optic sensing system employing an RF modulated source are described. In addition the paper discusses various configurations of the system itself, its components, and modulation and detection schemes. Experimental data are also presented.

  15. Optical Fiber Sensing Using Quantum Dots

    OpenAIRE

    Faramarz Farahi; José Luís Santos; Tito Trindade; Manuel António Martins; Pedro Jorge

    2007-01-01

    Recent advances in the application of semiconductor nanocrystals, or quantum dots, as biochemical sensors are reviewed. Quantum dots have unique optical properties that make them promising alternatives to traditional dyes in many luminescence based bioanalytical techniques. An overview of the more relevant progresses in the application of quantum dots as biochemical probes is addressed. Special focus will be given to configurations where the sensing dots are incorporated in sol...

  16. Sensing characteristics of birefringent microstructured polymer optical fiber

    DEFF Research Database (Denmark)

    Szczurowski, Marcin K.; Frazao, Orlando; Baptista, J. M.; Nielsen, Kristian; Bang, Ole; Urbanczyk, Waclaw

    2011-01-01

    We experimentally studied several sensing characteristics of a birefringent microstructured polymer optical fiber. The fiber exhibits a birefringence of the order 2×10-5 at 1.3 ?m because of two small holes adjacent to the core. In this fiber, we measured spectral dependence of phase and group modal birefringence, bending losses, polarimetric sensitivity to strain and temperature. The sensitivity to strain was also examined for intermodal interference observed in the spectral range below 0.8 ?m....

  17. Fiber Optic Wing Shape Sensing on NASA's Ikhana UAV

    Science.gov (United States)

    Richards, Lance; Parker, Allen R.; Ko, William L.; Piazza, Anthony

    2008-01-01

    This document discusses the development of fiber optic wing shape sensing on NASA's Ikhana vehicle. The Dryden Flight Research Center's Aerostructures Branch initiated fiber-optic instrumentation development efforts in the mid-1990s. Motivated by a failure to control wing dihedral resulting in a mishap with the Helios aircraft, new wing displacement techniques were developed. Research objectives for Ikhana included validating fiber optic sensor measurements and real-time wing shape sensing predictions; the validation of fiber optic mathematical models and design tools; assessing technical viability and, if applicable, developing methodology and approaches to incorporate wing shape measurements within the vehicle flight control system; and, developing and flight validating approaches to perform active wing shape control using conventional control surfaces and active material concepts.

  18. Photoinduced Electron Transfer Based Ion Sensing within an Optical Fiber

    Directory of Open Access Journals (Sweden)

    Tanya M. Monro

    2011-10-01

    Full Text Available We combine suspended-core microstructured optical fibers with the photoinduced electron transfer (PET effect to demonstrate a new type of fluorescent optical fiber-dip sensing platform for small volume ion detection. A sensor design based on a simple model PET-fluoroionophore system and small core microstructured optical fiber capable of detecting sodium ions is demonstrated. The performance of the dip sensor operating in a high sodium concentration regime (925 ppm Na+ and for lower sodium concentration environments (18.4 ppm Na+ is explored and future approaches to improving the sensor’s signal stability, sensitivity and selectivity are discussed.

  19. Fiber optic sensing in rapidly rotating mechanical structures

    Science.gov (United States)

    Zilberman, Shlomi; Berkovic, Garry; Shafir, Ehud; Saadi, Yair; Mazor, Ohad; Goichman, Tal

    2015-11-01

    A novel, generic approach for fiber-optical sensing in rapidly rotating structures is presented. This approach does not require optical ingress via the central rotation axis. In this work, strain sensing at rotation speeds of up to 5000 rpm is demonstrated, and higher speeds should be possible. We demonstrate measurement of the rotation-induced strain in a rotating body at 500 rpm intervals up to 5000 rpm, and results agree very well with predictions.

  20. Exposed-core chalcogenide microstructured optical fibers for chemical sensing

    Science.gov (United States)

    Troles, Johann; Toupin, Perrine; Brilland, Laurent; Boussard-Plédel, Catherine; Bureau, Bruno; Cui, Shuo; Mechin, David; Adam, Jean-Luc

    2013-05-01

    Chemical bonds of most of the molecules vibrate at a frequency corresponding to the near or mid infrared field. It is thus of a great interest to develop sensitive and portable devices for the detection of specific chemicals and biomolecules for various applications in health, the environment, national security and so on. Optical fibers define practical sensing tools. Chalcogenide glasses are known for their transparency in the infrared optical range and their ability to be drawn as fibers. They are consequently good candidates to be used in biological/chemical sensing. For that matter, in the past decade, chalcogenide glass fibers have been successfully implemented in evanescent wave spectroscopy experiments, for the detection of bio-chemical species in various fields of applications including microbiology and medicine, water pollution and CO2 detection. Different types of fiber can be used: single index fibers or microstructured fibers. Besides, in recent years a new configuration of microstructured fibers has been developed: microstructured exposed-core fibers. This design consists of an optical fiber with a suspended micron-scale core that is partially exposed to the external environment. This configuration has been chosen to elaborate, using the molding method, a chalcogenide fiber for chemical species detection. The sensitivity of this fiber to detect molecules such as propan-2-ol and acetone has been compared with those of single index fibers. Although evanescent wave absorption is inversely proportional to the fiber diameter, the result shows that an exposed-core fiber is much more sensitive than a single index fiber having a twice smaller external diameter.

  1. Neutron-sensing scintillating glass optical fiber detectors

    International Nuclear Information System (INIS)

    Pacific Northwest Laboratory (PNL) has developed and tested the highest-transmission neutron-sensing glass fibers reported in the open literature to date. By developing glass compositions specifically for fiber drawing and by using superior oxidationstate controls and rapid quenching, PNL produces, fiber with useful lengths in excess of 200 cm. These long fibers can be used in detectors. Test results on the fibers used as a form-fitting detector around a small storage container containing neutron and gamma ray sources are reported. Excellent neutron-gamma ray discrimination has been achieved. These neutron-sensing glass optical fibers provide for new methods for monitoring the inventory of, preventing the diversion of, and detecting the unauthorized transport of sensitive nuclear materials. As such, it represents a significant potential element in countering the threat of nuclear terrorism

  2. Extrinsic fiber optic displacement sensors and displacement sensing systems

    Science.gov (United States)

    Murphy, Kent A. (Roanoke, VA); Gunther, Michael F. (Blacksburg, VA); Vengsarkar, Ashish M. (Scotch Plains, NJ); Claus, Richard O. (Christiansburg, VA)

    1994-01-01

    An extrinsic Fizeau fiber optic sensor comprises a single-mode fiber, used as an input/output fiber, and a multimode fiber, used purely as a reflector, to form an air gap within a silica tube that acts as a Fizeau cavity. The Fresnel reflection from the glass/air interface at the front of the air gap (reference reflection) and the reflection from the air/glass interface at the far end of the air gap (sensing reflection) interfere in the input/output fiber. The two fibers are allowed to move in the silica tube, and changes in the air gap length cause changes in the phase difference between the reference reflection and the sensing reflection. This phase difference is observed as changes in intensity of the light monitored at the output arm of a fused biconical tapered coupler. The extrinsic Fizeau fiber optic sensor behaves identically whether it is surface mounted or embedded, which is unique to the extrinsic sensor in contrast to intrinsic Fabry-Perot sensors. The sensor may be modified to provide a quadrature phase shift extrinsic Fizeau fiber optic sensor for the detection of both the amplitude and the relative polarity of dynamically varying strain. The quadrature light signals may be generated by either mechanical or optical means. A plurality of the extrinsic sensors may connected in cascade and multiplexed to allow monitoring by a single analyzer.

  3. Multiparameter fiber optic sensing system for monitoring enhanced geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    William A. Challener

    2014-12-04

    The goal of this project was to design, fabricate and test an optical fiber cable which supports multiple sensing modalities for measurements in the harsh environment of enhanced geothermal systems. To accomplish this task, optical fiber was tested at both high temperatures and strains for mechanical integrity, and in the presence of hydrogen for resistance to darkening. Both single mode (SM) and multimode (MM) commercially available optical fiber were identified and selected for the cable based on the results of these tests. The cable was designed and fabricated using a tube-within-tube construction containing two MM fibers and one SM fiber, and without supporting gel that is not suitable for high temperature environments. Commercial fiber optic sensing instruments using Raman DTS (distributed temperature sensing), Brillouin DTSS (distributed temperature and strain sensing), and Raleigh COTDR (coherent optical time domain reflectometry) were selected for field testing. A microelectromechanical systems (MEMS) pressure sensor was designed, fabricated, packaged, and calibrated for high pressure measurements at high temperatures and spliced to the cable. A fiber Bragg grating (FBG) temperature sensor was also spliced to the cable. A geothermal well was selected and its temperature and pressure were logged. The cable was then deployed in the well in two separate field tests and measurements were made on these different sensing modalities. Raman DTS measurements were found to be accurate to ±5°C, even with some residual hydrogen darkening. Brillouin DTSS measurements were in good agreement with the Raman results. The Rayleigh COTDR instrument was able to detect some acoustic signatures, but was generally disappointing. The FBG sensor was used to determine the effects of hydrogen darkening, but drift over time made it unreliable as a temperature or pressure sensor. The MEMS sensor was found to be highly stable and accurate to better than its 0.1% calibration.

  4. Fiber sensing system based on a bragg grating and optical time domain reflectometry

    OpenAIRE

    Chin, Sanghoon; Thévenaz, Luc

    2013-01-01

    Optic fiber sensor characterized in that the sensing fiber is provided with a continuous Bragg grating covering the entire fiber length which is dedicated to sensing and along which spatially resolved measurements are performed.

  5. Recent progress in fiber optic pH sensing

    Science.gov (United States)

    Baldini, Francesco

    1991-03-01

    An analysis of the state of the art in pH sensing by optical fibers is presented. Advantages and drawbacks of this type of measurement are described. Different techniques in the optrode construction are taken into consideration and particular attention is also devoted to the overall optoelectronic system which must satisfy definite market requirements.

  6. Pressure sensing with optical fiber-tip air bubbles

    Science.gov (United States)

    Yu, Wenbing; Fu, Cailing; Wang, D. N.; Wang, Ying

    2013-09-01

    Optical fiber-tip air bubbles are demonstrated for pressure sensing with ultrahigh sensitivity. The air bubble locates in the end facet of a single mode fiber (SMF) that spliced with a silica tube, which is naturally formed and acts as a compressible Fabry-Pérot interferometer (FPI) cavity when immersing the silica tube into liquid. The proposed device exhibits pressure sensitivity of <1000 nm/kPa. This kind of compressible FPI cavity may find potential applications in highly sensitive pressure and/or acoustic sensing.

  7. Sensing characteristics of birefringent microstructured polymer optical fiber

    DEFF Research Database (Denmark)

    Szczurowski, Marcin K.; Frazao, Orlando; Baptista, J. M.; Nielsen, Kristian; Bang, Ole; Urbanczyk, Waclaw

    2011-01-01

    We experimentally studied several sensing characteristics of a birefringent microstructured polymer optical fiber. The fiber exhibits a birefringence of the order 2×10-5 at 1.3 ?m because of two small holes adjacent to the core. In this fiber, we measured spectral dependence of phase and group...... modal birefringence, bending losses, polarimetric sensitivity to strain and temperature. The sensitivity to strain was also examined for intermodal interference observed in the spectral range below 0.8 ?m. Finally, we showed that the material transmission windows shift as function of the applied strain...

  8. Distributed Fiber Optic Gas Sensing for Harsh Environment

    Energy Technology Data Exchange (ETDEWEB)

    Juntao Wu

    2008-03-14

    This report summarizes work to develop a novel distributed fiber-optic micro-sensor that is capable of detecting common fossil fuel gases in harsh environments. During the 32-month research and development (R&D) program, GE Global Research successfully synthesized sensing materials using two techniques: sol-gel based fiber surface coating and magnetron sputtering based fiber micro-sensor integration. Palladium nanocrystalline embedded silica matrix material (nc-Pd/Silica), nanocrystalline palladium oxides (nc-PdO{sub x}) and palladium alloy (nc-PdAuN{sub 1}), and nanocrystalline tungsten (nc-WO{sub x}) sensing materials were identified to have high sensitivity and selectivity to hydrogen; while the palladium doped and un-doped nanocrystalline tin oxide (nc-PdSnO{sub 2} and nc-SnO{sub 2}) materials were verified to have high sensitivity and selectivity to carbon monoxide. The fiber micro-sensor comprises an apodized long-period grating in a single-mode fiber, and the fiber grating cladding surface was functionalized by above sensing materials with a typical thickness ranging from a few tens of nanometers to a few hundred nanometers. GE found that the morphologies of such sensing nanomaterials are either nanoparticle film or nanoporous film with a typical size distribution from 5-10 nanometers. nc-PdO{sub x} and alloy sensing materials were found to be highly sensitive to hydrogen gas within the temperature range from ambient to 150 C, while nc-Pd/Silica and nc-WO{sub x} sensing materials were found to be suitable to be operated from 150 C to 500 C for hydrogen gas detection. The palladium doped and un-doped nc-SnO{sub 2} materials also demonstrated sensitivity to carbon monoxide gas at approximately 500 C. The prototyped fiber gas sensing system developed in this R&D program is based on wavelength-division-multiplexing technology in which each fiber sensor is identified according to its transmission spectra features within the guiding mode and cladding modes. The interaction between the sensing material and fossil fuel gas results in a refractive index change and optical absorption in the sensing layer. This induces mode coupling strength and boundary conditions changes and thereby shifts the central wavelengths of the guiding mode and cladding modes propagation. GE's experiments demonstrated that such an interaction between the fossil fuel gas and sensing material not only shifts the central wavelengths of the guide mode and cladding modes propagation, but also alters their power loss characteristics. The integrated fiber gas sensing system includes multiple fiber gas sensors, fiber Bragg grating-based temperature sensors, fiber optical interrogator, and signal processing software.

  9. Kalman filter for noise removal in optical fiber sensing system

    Science.gov (United States)

    Liu, Tao; Zhang, Wen-ping; Chen, Hui-fang; Feng, Gui-Lan

    2012-10-01

    Noise in the optical fiber sensing system, produced in laser, transmission, demodulation and environment, reduces the Signal-to-Noise Ratio (SNR) and the measuring accuracy of the whole system . In this paper, a statistical approach based on Kalman-filter is undertaken to removal noise of the measured object real time, and then to improve the accuracy of the fiber sensing system. The temperature induced by fiber sensing is modeled as a discrete-time state variable by a Gauss-Markov random process with the Gaussian white and additive noise in the linear dynamic system. Based on Bayesian MAP Inference and minimum mean-square error criterion (MMSE), gain of the kalman-filter and the state error covariance can be regulated by Measurement Update equations to correct posteriori state estimate. Such recursive algorithm can finally get the optimum estimator of the state through time. The performances of the model and the algorithm are investigated in the DOFS temperature sensing system. Variance is used to evaluate its performance in noise removal. At the same time, the experimental results of the method proposed is compared with original measurement data analysis. The algorithm performs more improvement in accuracy of the fiber sensing system, and implements the real-time measurement.

  10. Optical fiber sensing of human skin emanations

    Science.gov (United States)

    Lee, S.-W.; Wang, T.; Selyanchyn, R.; Korposh, S.; James, S. W.

    2015-07-01

    An evanescent-wave optical fibre sensor modified with tetrakis(4-sulfophenyl)porphine (TSPP) and poly(allylamine hydrochloride) (PAH) bilayers using an layer-by-layer (LbL) approach was tested to measure the gas emitted from human skin. Optical intensity changes at different wavelengths in the transmission spectrum of the porphyrin-based film were induced by the human skin gas and measured as sensor response. Influence of relative humidity, which can be a major interference to sensor response, was significantly different when compared to the influence of skin emanations. Responses of the current optical sensor system could be considered as composite sensor array, where different optical wavelengths act as channels that have selective response to specific volatile compounds. Data obtained from the sensor system was analyzed through principal component analysis (PCA). This approach enabled to distinguish skin odors of different people and their altered physiological conditions after alcohol consumption.

  11. Monitoring of Thermal Protection Systems using Robust Self-Organizing Optical Fiber Sensing Networks Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Objectives a) Development, evaluation and demonstration of a dynamically reconfigurable optical fiber sensing network that is interrogated using the optical...

  12. Melamine sensing based on evanescent field enhanced optical fiber sensor

    Science.gov (United States)

    Luo, Ji; Yao, Jun; Wang, Wei-min; Zhuang, Xu-ye; Ma, Wen-ying; Lin, Qiao

    2013-08-01

    Melamine is an insalubrious chemical, and has been frequently added into milk products illegally, to make the products more protein-rich. However, it can cause some various diseases, such as kidney stones and bladder cancer. In this paper, a novel optical fiber sensor with high sensitivity based on absorption of the evanescent field for melamine detection is successfully proposed and developed. Different concentrations of melamine changing from 0 to 10mg/mL have been detected using the micro/nano-sensing fiber decorated with silver nanoparticles cluster layer. As the concentration increases, the sensing fiber's output intensity gradually deceases and the absorption of the analyte becomes large. The concentration changing of 1mg/ml can cause the absorbance varying 0.664 and the limit of the melamine detectable concentration is 1ug/mL. Besides, the coupling properties between silver nanoparticles have also been analyzed by the FDTD method. Overall, this evanescent field enhanced optical fiber sensor has potential to be used in oligo-analyte detection and will promote the development of biomolecular and chemical sensing applications.

  13. Extreme temperature sensing using Brillouin scattering in optical fibers

    OpenAIRE

    Fellay, Alexandre

    2003-01-01

    Stimulated Brillouin scattering in silica-based optical fibers may be considered from two different and complementary standpoints. For a physicist, this interaction of light and pressure wave in a material, or equivalently in quantum theory terms between photons and phonons, gives some glimpses of the atomic structure of the solid and of its vibration modes. For an applied engineer, the same phenomenon may be put to good use as a sensing mechanism for distributed measurements, thanks to the d...

  14. Exposed core microstructured optical fiber Bragg gratings: refractive index sensing.

    Science.gov (United States)

    Warren-Smith, Stephen C; Monro, Tanya M

    2014-01-27

    Bragg gratings have been written in exposed-core microstructured optical fibers for the first time using a femtosecond laser. Second and third order gratings have been written and both show strong reflectivity at 1550 nm, with bandwidths as narrow as 60 pm. Due to the penetration of the guided field outside the fiber the Bragg reflections are sensitive to the external refractive index. As different modes have different sensitivities to refractive index but the same temperature sensitivity the sensor can provide temperature-compensated refractive index measurements. Since these Bragg gratings have been formed by physical ablation, these devices can also be used for high temperature sensing, demonstrated here up to 800°C. The fibers have been spliced to single mode fiber for improved handling and integration with commercial interrogation units. PMID:24515155

  15. New trends and applications of optical fiber sensing technologies at the NEL-FOST

    Science.gov (United States)

    Yang, Minghong; Huang, Chujia; Yuan, Yinquan; Ding, Liyun; Zhou, Ciming

    2015-07-01

    This paper reviews the recent development of optical fiber sensors at the National Engineering Laboratory for Optic Fiber Sensing Technologies (NEL-FOST) at Wuhan University of Technology. Integration of optical fiber with sensitive thin films will new possibilities for industry application, such as optical fiber hydrogen sensors based on Pt-doped WO3 coatings, fiber humidity sensors with porous oxide coating and high-temperature sapphire fiber sensors based on multilayer coating on fiber tip. Ultra-weak FBG array with thousand of FBGs with on-line draw tower technology will enable FBG sensing network with large capacity, also improved sensing performance and mechanical stability.

  16. Optical fiber sensing technology in the pipeline industry

    Energy Technology Data Exchange (ETDEWEB)

    Braga, A.M.B.; Llerena, R.W.A. [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Mecanica]. E-mail: abraga@mec.puc-rio.br; roberan@mec.puc-rio.br; Valente, L.C.G.; Regazzi, R.D. [Gavea Sensors, Rio de Janeiro, RJ (Brazil)]. E-mail: guedes@gaveasensors.com; regazzi@gaveasensors.com

    2003-07-01

    This paper is concerned with applications of optical fiber sensors to pipeline monitoring. The basic principles of optical fiber sensors are briefly reviewed, with particular attention to fiber Bragg grating technology. Different potential applications in the pipeline industry are discussed, and an example of a pipeline strain monitoring system based on optical fiber Bragg grating sensors is presented. (author)

  17. Frequency-Shifted Interferometry — A Versatile Fiber-Optic Sensing Technique

    OpenAIRE

    Fei Ye; Yiwei Zhang; Bing Qi; Li Qian

    2014-01-01

    Fiber-optic sensing is a field that is developing at a fast pace. Novel fiber-optic sensor designs and sensing principles constantly open doors for new opportunities. In this paper, we review a fiber-optic sensing technique developed in our research group called frequency-shifted interferometry (FSI). This technique uses a continuous-wave light source, an optical frequency shifter, and a slow detector. We discuss the operation principles of several FSI implementations and show their applicati...

  18. Microwave assisted reconstruction of optical interferograms for distributed fiber optic sensing.

    Science.gov (United States)

    Huang, Jie; Hua, Lei; Lan, Xinwei; Wei, Tao; Xiao, Hai

    2013-07-29

    This paper reports a distributed fiber optic sensing technique through microwave assisted separation and reconstruction of optical interferograms in spectrum domain. The approach involves sending a microwave-modulated optical signal through cascaded fiber optic interferometers. The microwave signal was used to resolve the position and reflectivity of each sensor along the optical fiber. By sweeping the optical wavelength and detecting the modulation signal, the optical spectrum of each sensor can be reconstructed. Three cascaded fiber optic extrinsic Fabry-Perot interferometric sensors were used to prove the concept. Their microwave-reconstructed interferogram matched well with those recorded individually using an optical spectrum analyzer. The application in distributed strain measurement has also been demonstrated. PMID:23938685

  19. Reflection based Extraordinary Optical Transmission Fiber Optic Probe for Refractive Index Sensing

    OpenAIRE

    Lan, Xinwei; Cheng, Baokai; Yang, Qingbo; HUANG, JIE; Wang, Hanzheng; Ma, Yinfa; Shi, Honglan; Xiao, Hai

    2014-01-01

    Fiber optic probes for chemical sensing based on the extraordinary optical transmission (EOT) phenomenon are designed and fabricated by perforating subwavelength hole arrays on the gold film coated optical fiber endface. The device exhibits a red shift in response to the surrounding refractive index increases with high sensitivity, enabling a reflection-based refractive index sensor with a compact and simple configuration. By choosing the period of hole arrays, the sensor can be designed to o...

  20. Calibration and Deployment of a Fiber-Optic Sensing System for Monitoring Debris Flows

    OpenAIRE

    Tsung-Mo Tien; Hsiao-Yuen Yin; Ping-Sen Chen; Ching-Jer Huang; Chung-Ray Chu

    2012-01-01

    This work presents a novel fiber-optic sensing system, capable of monitoring debris flows or other natural hazards that produce ground vibrations. The proposed sensing system comprises a demodulator (BraggSCOPE, FS5500), which includes a broadband light source and a data logger, a four-port coupler and four Fiber Bragg Grating (FBG) accelerometers. Based on field tests, the performance of the proposed fiber-optic sensing system is compared with that of a conventional sensing system that inclu...

  1. Extreme temperature sensing using brillouin scattering in optical fibers

    CERN Document Server

    Fellay, Alexandre

    Stimulated Brillouin scattering in silica-based optical fibers may be considered from two different and complementary standpoints. For a physicist, this interaction of light and pressure wave in a material, or equivalently in quantum theory terms between photons and phonons, gives some glimpses of the atomic structure of the solid and of its vibration modes. For an applied engineer, the same phenomenon may be put to good use as a sensing mechanism for distributed measurements, thanks to the dependence of the scattered light on external parameters such as the temperature, the pressure or the strain applied to the fiber. As far as temperature measurements are concerned, Brillouin-based distributed sensors have progressively gained wide recognition as efficient systems, even if their rather high cost still restricts the number of their applications. Yet they are generally used in a relatively narrow temperature range around the usual ambient temperature; in this domain, the frequency of the scattered light incre...

  2. Mechanically induced long period fiber gratings on single mode tapered optical fiber for structure sensing applications

    Science.gov (United States)

    Pulido-Navarro, María. G.; Marrujo-García, Sigifredo; Álvarez-Chávez, José A.; Velázquez-González, Jesús S.; Martínez-Piñón, Fernando; Escamilla-Ambrosio, Ponciano J.

    2015-08-01

    The modal characteristics of tapered single mode optical fibers and its strain sensing characteristics by using mechanically induced long period fiber gratings are presented in this work. Both Long Period Fiber Gratings (LPFG) and fiber tapers are fiber devices that couple light from the core fiber into the fiber cladding modes. The mechanical LPFG is made up of two plates, one flat and the other grooved. For this experiment the grooved plate was done on an acrylic slab with the help of a computer numerical control machine. The manufacturing of the tapered fiber is accomplished by applying heat using an oxygen-propane flame burner and stretching the fiber, which protective coating has been removed. Then, a polymer-tube-package is added in order to make the sensor sufficiently stiff for the tests. The mechanical induced LPFG is accomplished by putting the tapered fiber in between the two plates, so the taper acquires the form of the grooved plate slots. Using a laser beam the transmission spectrum showed a large peak transmission attenuation of around -20 dB. The resultant attenuation peak wavelength in the transmission spectrum shifts with changes in tension showing a strain sensitivity of 2pm/??. This reveals an improvement on the sensitivity for structure monitoring applications compared with the use of a standard optical fiber. In addition to the experimental work, the supporting theory and numerical simulation analysis are also included.

  3. Development of self-sensing BFRP bars with distributed optic fiber sensors

    Science.gov (United States)

    Tang, Yongsheng; Wu, Zhishen; Yang, Caiqian; Shen, Sheng; Wu, Gang; Hong, Wan

    2009-03-01

    In this paper, a new type of self-sensing basalt fiber reinforced polymer (BFRP) bars is developed with using the Brillouin scattering-based distributed optic fiber sensing technique. During the fabrication, optic fiber without buffer and sheath as a core is firstly reinforced through braiding around mechanically dry continuous basalt fiber sheath in order to survive the pulling-shoving process of manufacturing the BFRP bars. The optic fiber with dry basalt fiber sheath as a core embedded further in the BFRP bars will be impregnated well with epoxy resin during the pulling-shoving process. The bond between the optic fiber and the basalt fiber sheath as well as between the basalt fiber sheath and the FRP bar can be controlled and ensured. Therefore, the measuring error due to the slippage between the optic fiber core and the coating can be improved. Moreover, epoxy resin of the segments, where the connection of optic fibers will be performed, is uncured by isolating heat from these parts of the bar during the manufacture. Consequently, the optic fiber in these segments of the bar can be easily taken out, and the connection between optic fibers can be smoothly carried out. Finally, a series of experiments are performed to study the sensing and mechanical properties of the propose BFRP bars. The experimental results show that the self-sensing BFRP bar is characterized by not only excellent accuracy, repeatability and linearity for strain measuring but also good mechanical property.

  4. Magnetic Sensing with Ferrofluid and Fiber Optic Connectors

    Directory of Open Access Journals (Sweden)

    Daniel Homa

    2014-02-01

    Full Text Available A simple, cost effective and sensitive fiber optic magnetic sensor fabricated with ferrofluid and commercially available fiber optic components is described in this paper. The system uses a ferrofluid infiltrated extrinsic Fabry-Perot interferometer (EFPI interrogated with an infrared wavelength spectrometer to measure magnetic flux density. The entire sensing system was developed with commercially available components so it can be easily and economically reproduced in large quantities. The device was tested with two different ferrofluid types over a range of magnetic flux densities to verify performance. The sensors readily detected magnetic flux densities in the range of 0.5 mT to 12.0 mT with measurement sensitivities in the range of 0.3 to 2.3 nm/mT depending on ferrofluid type. Assuming a conservative wavelength resolution of 0.1 nm for state of the art EFPI detection abilities, the estimated achievable measurement resolution is on the order 0.04 mT. The inherent small size and basic structure complimented with the fabrication ease make it well-suited for a wide array of research, industrial, educational and military applications.

  5. Analyzing Fourier Transforms for NASA DFRC's Fiber Optic Strain Sensing System

    Science.gov (United States)

    Fiechtner, Kaitlyn Leann

    2010-01-01

    This document provides a basic overview of the fiber optic technology used for sensing stress, strain, and temperature. Also, the document summarizes the research concerning speed and accuracy of the possible mathematical algorithms that can be used for NASA DFRC's Fiber Optic Strain Sensing (FOSS) system.

  6. Multicore optical fiber grating array fabrication for medical sensing applications

    Science.gov (United States)

    Westbrook, Paul S.; Feder, K. S.; Kremp, T.; Taunay, T. F.; Monberg, E.; Puc, G.; Ortiz, R.

    2015-03-01

    In this work we report on a fiber grating fabrication platform suitable for parallel fabrication of Bragg grating arrays over arbitrary lengths of multicore optical fiber. Our system exploits UV transparent coatings and has precision fiber translation that allows for quasi-continuous grating fabrication. Our system is capable of both uniform and chirped fiber grating array spectra that can meet the demands of medical sensors including high speed, accuracy, robustness and small form factor.

  7. Dynamic Response of Tapered Optical Multimode Fiber Coated with Carbon Nanotubes for Ethanol Sensing Application

    OpenAIRE

    Arafat Shabaneh; Saad Girei; Punitha Arasu; Mohd Mahdi; Suraya Rashid; Suriati Paiman; Mohd Yaacob

    2015-01-01

    Ethanol is a highly combustible chemical universally designed for biomedical applications. In this paper, optical sensing performance of tapered multimode fiber tip coated with carbon nanotube (CNT) thin film towards aqueous ethanol with different concentrations is investigated. The tapered optical multimode fiber tip is coated with CNT using drop-casting technique and is annealed at 70 °C to enhance the binding of the nanomaterial to the silica fiber tip. The optical fiber tip and the CNT se...

  8. Molecular alignment relaxation in polymer optical fibers for sensing applications

    Science.gov (United States)

    Stajanca, Pavol; Cetinkaya, Onur; Schukar, Marcus; Mergo, Pawel; Webb, David J.; Krebber, Katerina

    2016-03-01

    A systematic study of annealing behavior of drawn PMMA fibers was performed. Annealing dynamics were investigated under different environmental conditions by fiber longitudinal shrinkage monitoring. The shrinkage process was found to follow a stretched exponential decay function revealing the heterogeneous nature of the underlying molecular dynamics. The complex dependence of the fiber shrinkage on initial degree of molecular alignment in the fiber, annealing time and temperature was investigated and interpreted. Moreover, humidity was shown to have a profound effect on the annealing process, which was not recognized previously. Annealing was also shown to have considerable effect on the fiber mechanical properties associated with the relaxation of molecular alignment in the fiber. The consequences of fiber annealing for the climatic stability of certain polymer optical fiber-based sensors are discussed, emphasizing the importance of fiber controlled pre-annealing with respect to the foreseeable operating conditions.

  9. Optical sensing in high voltage transmission lines using power over fiber and free space optics

    Science.gov (United States)

    Rosolem, João Batista; Bassan, Fabio Renato; Penze, Rivael Strobel; Leonardi, Ariovaldo Antonio; Fracarolli, João Paulo Vicentini; Floridia, Claudio

    2015-12-01

    In this work we propose the use of power over fiber (PoF) and free space optics (FSO) techniques to powering and receive signals from an electrical current sensor placed at high voltage potential using a pair of optical collimators. The technique evaluation was performed in a laboratorial prototype using 62.5/125 ?m multimode fiber to study the sensitivity of the optical alignment and the influence of the collimation process in the sensing system wavelengths: data communication (1310 nm) and powering (830 nm). The collimators were installed in a rigid electric insulator in order to maintain the stability of transmission.

  10. Biochemical sensing application based on optical fiber evanescent wave sensor

    Science.gov (United States)

    Lv, Xiaoyi; Mo, Jiaqing; Xu, Liang; Jia, Zhenhong

    2015-08-01

    We have designed a novel evanescent field fiber optic biosensors with porous silicon dioxide cladding. The pore size of porous silicon dioxide cladding is about 100 nm in diameter. Biological molecules were immobilized to the porous silicon dioxide cladding used APTES and glutaraldehyde. Refractive index of cladding used Bruggemann's effective medium theory. We carried out simulations of changing in light intensity in optical fiber before and after chemical coupling of biomolecules. This novel optical fiber evanescent wave biosensor has a great potential in clinical chemistry for rapid and convenient determination of biological molecule.

  11. Frequency-Shifted Interferometry — A Versatile Fiber-Optic Sensing Technique

    Directory of Open Access Journals (Sweden)

    Fei Ye

    2014-06-01

    Full Text Available Fiber-optic sensing is a field that is developing at a fast pace. Novel fiber-optic sensor designs and sensing principles constantly open doors for new opportunities. In this paper, we review a fiber-optic sensing technique developed in our research group called frequency-shifted interferometry (FSI. This technique uses a continuous-wave light source, an optical frequency shifter, and a slow detector. We discuss the operation principles of several FSI implementations and show their applications in fiber length and dispersion measurement, locating weak reflections along a fiber link, fiber-optic sensor multiplexing, and high-sensitivity cavity ring-down measurement. Detailed analysis of FSI system parameters is also presented.

  12. Asymmetrically and symmetrically coated tapered optical fiber for sensing applications

    Science.gov (United States)

    Del Villar, Ignacio; Socorro, Abian B.; Corres, Jesus M.; Arregui, Francisco J.; Matias, Ignacio R.

    2015-09-01

    The deposition of a non-metallic thin-film in a symmetrically coated tapered optical fiber leads to the generation of resonances due to guidance of a mode in the thin-film. At certain conditions, the resonances overlap each other, which can be avoided with an asymmetric coated tapered optical fiber, which permits to obtain resonances for TM and TE polarization separately. Numerical results showing the sensitivity to coating thickness and surrounding medium refractive index are also presented for both polarizations.

  13. Huge capacity fiber-optic sensing network based on ultra-weak draw tower gratings

    Science.gov (United States)

    Yang, Minghong; Bai, Wei; Guo, Huiyong; Wen, Hongqiao; Yu, Haihu; Jiang, Desheng

    2016-03-01

    This paper reviews the work on huge capacity fiber-optic sensing network based on ultra-weak draw tower gratings developed at the National Engineering Laboratory for Fiber Optic Sensing Technology (NEL-FOST), Wuhan University of Technology, China. A versatile drawing tower grating sensor network based on ultra-weak fiber Bragg gratings (FBGs) is firstly proposed and demonstrated. The sensing network is interrogated with time- and wavelength-division multiplexing method, which is very promising for the large-scale sensing network.

  14. Probing the Ultimate Limit of Fiber-Optic Strain Sensing

    Science.gov (United States)

    Gagliardi, G.; Salza, M.; Avino, S.; Ferraro, P.; De Natale, P.

    2010-11-01

    The measurement of relative displacements and deformations is important in many fields such as structural engineering, aerospace, geophysics, and nanotechnology. Optical-fiber sensors have become key tools for strain measurements, with sensitivity limits ranging between 10â??9 and 10â??6ε hertz (Hz)â??1/2 (where ε is the fractional length change). We report on strain measurements at the 10â??13ε-Hzâ??1/2 level using a fiber Bragg-grating resonator with a diode-laser source that is stabilized against a quartz-disciplined optical frequency comb, thus approaching detection limits set by thermodynamic phase fluctuations in the fiber. This scheme may provide a route to a new generation of strain sensors that is entirely based on fiber-optic systems, which are aimed at measuring fundamental physical quantities; for example, in gyroscopes, accelerometers, and gravity experiments.

  15. Fiber-optic-coupled dosemeter for remote optical sensing of radiation

    International Nuclear Information System (INIS)

    Remote sensing technologies for the detection and measurement of ionizing radiation exposure are of current interest for applications such as patient dose verification during radiotherapy and the monitoring of environmental contaminants. Fiberoptic-based sensing is attractive due to the advantages of small size, low cost, long life and freedom from electromagnetic interference. Several fiberoptic-based radiation sensing systems have been described that utilize radiation induced changes in the optical characteristics of the fiber such as reduced transmission as a result of darkening of the glass, optical phase shifts due to heating, or changes in the birefringence of a polarization-maintaining fiber. The measurement of radiation induced darkening is limited in both sensitivity and dynamic range and requires long fiber lengths. Phase shift measurements require the use of single-mode lasers, phase sensitive interferometric detection, long fiber lengths and complex signal processing techniques. Alternatively, thermoluminescent (TL) phosphor powders have been coated onto fiberoptic cables and remote dosimetry measurements performed using traditional laser heating techniques. The sensitivity is limited by the requirement for a very thin layer of phosphor material, due to problems associated with light scattering and efficient heating by thermal diffusion. In this paper we report the development of an all-optical, fiber-optic-coupled, thermoluminescence dosemeter for remote radiation sensing that offers significant advantages compared to previous technologies. We recently reported the development of an optically transparent, TL glass material having exceptionally good characteristics for traditional dosimetry applications. We also reported a modified TL glass incorporating a rare earth ion dopant in order to absorb light from a semiconductor laser and utilize the absorbed light energy to internally heat the glass and release the trapped electrons. (author)

  16. Fiber-optic multipoint radiation sensing system using waveguide scintillators

    International Nuclear Information System (INIS)

    Novel fiber-optic radiation sensors and a multipoint measurement method that takes advantage of them have been developed. The new sensor design, which we call a 'waveguide scintillator', consists of a scintillating material and a wavelength-shifting fiber (WLSF). The WLSF is embedded in the scintillating material, and each end is connected to a transparent optical fiber. These waveguide scintillators can be connected in series along an optical fiber loop to form a radiation monitoring system, and each end of the fiber loop is terminated with a photodetector. This new radiation monitoring arrangement dispenses with the need for electronic apparatus at each measuring point and consequently improves resistance to noise. Furthermore, it offers the advantages of multipoint monitoring - meaning that radiation intensity can be measured at multiple sensors - using only two photodetectors. We have examined the light output characteristics and time resolution of a prototype arrangement of these new waveguide scintillators, thus confirming the feasibility of multipoint measurements using a system of multiple waveguide scintillators connected in series in an optical fiber loop. (author)

  17. Chalcogenide optical fibers for mid-infrared sensing

    Science.gov (United States)

    Bureau, Bruno; Boussard, Catherine; Cui, Shuo; Chahal, Radwan; Anne, Marie Laure; Nazabal, Virginie; Sire, Olivier; Loréal, Olivier; Lucas, Pierre; Monbet, Valérie; Doualan, Jean-Louis; Camy, Patrice; Tariel, Hugues; Charpentier, Frédéric; Quetel, Lionel; Adam, Jean-Luc; Lucas, Jacques

    2014-02-01

    Chalcogenide glasses are a matchless material as far as mid-infrared (IR) applications are concerned. They transmit light typically from 2 to 12 ?m and even as far as 20 ?m depending on their composition, and numerous glass compositions can be designed for optical fibers. One of the most promising applications of these fibers consists in implementing fiber evanescent wave spectroscopy, which enables detection of the mid-IR signature of most biomolecules. The principles of fiber evanescent wave spectroscopy are recalled together with the benefit of using selenide glass to carry out this spectroscopy. Then, two large-scale studies in recent years in medicine and food safety are exposed. To conclude, the future strategy is presented. It focuses on the development of rare earth-doped fibers used as mid-IR sources on one hand and tellurium-based glasses to shift the limit of detection toward longer wavelength on the other hand.

  18. NASA Armstrong Flight Research Center (AFRC) Fiber Optic Sensing System (FOSS) Technology

    Science.gov (United States)

    Richards, Lance; Parker, Allen R.; Piazza, Anthony; Chan, Patrick; Hamory, Phil; Pena, Frank

    2014-01-01

    Attached is a power point presentation created to assist the Tech Transfer Office and the FOSS project team members in responding to inquiries from the public about the capabilities of the Fiber Optic Sensing System.

  19. Remote Management for Multipoint Sensing Systems Using Hetero-Core Spliced Optical Fiber Sensors

    Directory of Open Access Journals (Sweden)

    Lee See Goh

    2013-12-01

    Full Text Available This paper describes the design and experimental verification of a multipoint sensing system with hetero-core spliced optical fiber sensors and its remote management using an internet-standard protocol. The study proposes two different types of design and conducts experiments to verify those systems’ feasibility. In order to manage the sensing systems remotely, the management method uses a standard operation and maintenance protocol for internet: the Simple Network Management Protocol is proposed. The purpose of this study is to construct a multipoint sensing system remote management tool by which the system can also determine the status and the identity of fiber optic sensors. The constructed sensing systems are verified and the results have demonstrated that the first proposed system can distinguish the responses from different hetero-core spliced optical fiber sensors remotely. The second proposed system shows that data communications are performed successfully while identifying the status of hetero-core spliced optical fiber sensors remotely.

  20. Remote management for multipoint sensing systems using hetero-core spliced optical fiber sensors.

    Science.gov (United States)

    Goh, Lee See; Anoda, Yuji; Kazuhiro, Watanabe; Shinomiya, Norihiko

    2013-01-01

    This paper describes the design and experimental verification of a multipoint sensing system with hetero-core spliced optical fiber sensors and its remote management using an internet-standard protocol. The study proposes two different types of design and conducts experiments to verify those systems' feasibility. In order to manage the sensing systems remotely, the management method uses a standard operation and maintenance protocol for internet: the Simple Network Management Protocol is proposed. The purpose of this study is to construct a multipoint sensing system remote management tool by which the system can also determine the status and the identity of fiber optic sensors. The constructed sensing systems are verified and the results have demonstrated that the first proposed system can distinguish the responses from different hetero-core spliced optical fiber sensors remotely. The second proposed system shows that data communications are performed successfully while identifying the status of hetero-core spliced optical fiber sensors remotely. PMID:24379051

  1. Liquid Seal for Temperature Sensing with Fiber-Optic Refractometers

    OpenAIRE

    Ben Xu; Jianqing Li; Yi Li,; Jianglei Xie; Xinyong Dong

    2014-01-01

    Liquid sealing is an effective method to convert a fiber-optic refractometer into a simple and highly sensitive temperature sensor. A refractometer based on the thin-core fiber modal interferometer is sealed in a capillary tube filled with Cargille oil. Due to the thermo-optic effect of the sealing liquid, the high refractive-index sensitivity refractometer is subsequently sensitive to the ambient temperature. It is found that the liquid-sealed sensor produces a highest sensitivity of ?2.30 n...

  2. Surface plasmon sensing of gas phase contaminants using optical fiber.

    Energy Technology Data Exchange (ETDEWEB)

    Thornberg, Steven Michael; White, Michael I.; Rumpf, Arthur Norman; Pfeifer, Kent Bryant

    2009-10-01

    Fiber-optic gas phase surface plasmon resonance (SPR) detection of several contaminant gases of interest to state-of-health monitoring in high-consequence sealed systems has been demonstrated. These contaminant gases include H{sub 2}, H{sub 2}S, and moisture using a single-ended optical fiber mode. Data demonstrate that results can be obtained and sensitivity is adequate in a dosimetric mode that allows periodic monitoring of system atmospheres. Modeling studies were performed to direct the design of the sensor probe for optimized dimensions and to allow simultaneous monitoring of several constituents with a single sensor fiber. Testing of the system demonstrates the ability to detect 70mTorr partial pressures of H{sub 2} using this technique and <280 {micro}Torr partial pressures of H{sub 2}S. In addition, a multiple sensor fiber has been demonstrated that allows a single fiber to measure H{sub 2}, H{sub 2}S, and H{sub 2}O without changing the fiber or the analytical system.

  3. Research on spectral resource optimization and self-healing technology of hybrid optical fiber sensing network

    Science.gov (United States)

    Chen, Cheng; Sang, Mei; Ge, Chunfeng; Chen, Guanghui; Liu, Tiegen

    2015-08-01

    We propose an optical-fiber-sensing-network (OFSN) to allow hybrid fiber sensors working in the same network and it achieves self-healing function. The discrete and distributed optical fiber sensors can be connected in sub-layers of the network. WDM-OTDM technique is introduced to convert multi-wavelengths of light source into a specific arranged wavelength in each sub-layer. Thus every sub-layer can share the system spectrum resources, and sensing signals of each sub-layer are transmitted together in the backbone network. To achieve self-healing function, double-ring structure is adopted in the backbone network. Node microprocessor program is designed to make switching to the protect fiber when working fiber is broken. The experimental backbone setup of the network demonstrates the practical reliability and intelligence of the optical sensing network.

  4. Research On Fiber Optic Sensing Systems And Their Application As Final Repository Monitoring Tools

    International Nuclear Information System (INIS)

    For several years, fiber-optic sensing devices had been used for straightforward on/off monitoring functions such as presence and position detection. Recently, they gained interest as they offer a novel, exciting technology for a multitude of sensing applications. In the deep geological environment most physical properties, and thus most parameters important to safety, can be measured with fiber-optic technology. Typical examples are displacements, strains, radiation dose and dose rate, presence of some gases, temperature, pressure, etc. Their robustness, immunity to electromagnetic interference, as well as their large bandwidths and data rates ensure high reliability and superior performance. Moreover, the networking capabilities of meanwhile available fiber-optic sensors allow for efficient management of large sensor systems. Distributed sensing with multiple sensing locations on a single fiber reduces significantly the number of cables and connecting points. Reliable, cost effective, and maintenance-free solutions can thus be implemented

  5. Reflection based Extraordinary Optical Transmission Fiber Optic Probe for Refractive Index Sensing.

    Science.gov (United States)

    Lan, Xinwei; Cheng, Baokai; Yang, Qingbo; Huang, Jie; Wang, Hanzheng; Ma, Yinfa; Shi, Honglan; Xiao, Hai

    2014-03-31

    Fiber optic probes for chemical sensing based on the extraordinary optical transmission (EOT) phenomenon are designed and fabricated by perforating subwavelength hole arrays on the gold film coated optical fiber endface. The device exhibits a red shift in response to the surrounding refractive index increases with high sensitivity, enabling a reflection-based refractive index sensor with a compact and simple configuration. By choosing the period of hole arrays, the sensor can be designed to operate in the near infrared telecommunication wavelength range, where the abundant source and detectors are available for easy instrumentation. The new sensor probe is demonstrated for refractive index measurement using refractive index matching fluids. The sensitivity reaches 573 nm/RIU in the 1.333~1.430 refractive index range. PMID:24574579

  6. Applicability study of optical fiber distribution sensing to nuclear facilities

    International Nuclear Information System (INIS)

    Optical fibers have advantages like flexible configuration, intrinsic immunity for electromagnetic fields etc., and they have been used for signal transmission and as optical fiber sensors (OFSs). By some of these sensor techniques, continuous or discrete distribution of physical parameters can be measured. Here, in order to discuss the applicability of these OFSs to nuclear facilities, irradiation experiments to optical fibers were carried out using the fast neutron source reactor 'YAYOI' and a 60Co ? source. It has been shown that, under irradiation with fast neutrons, the radiation induced loss increase almost linearly with the neutron fluence. On the other hand, when irradiated with 60Co ? rays, the loss shows a saturation tendency. As an example of the OFSs, applicability of the Raman distributed temperature sensor (RDTS) to the monitoring of nuclear facilities has been examined. Two correction techniques for radiation induced errors have been developed and for the demonstration of their feasibility, measurements were carried out along the primary piping system of the experimental fast reactor: JOYO. During the continuous measurements with the total dose of more than 107[R], the radiation induced errors showed a saturating tendency and the feasibility of the loss correction technique was demonstrated. Although the time response of the system should be improved, the RDTS can be expected as a noble temperature monitor in nuclear facilities. (author)

  7. Integration of fiber optical shape sensing with medical visualization for minimal-invasive interventions

    Science.gov (United States)

    Paetz, Torben; Waltermann, Christian; Angelmahr, Martin; Ojdanic, Darko; Schade, Wolfgang; Witte, Michael; Hahn, Horst Karl

    2015-03-01

    We present a fiber optical shape sensing system that allows to track the shape of a standard telecom fiber with fiber Bragg grating. The shape sensing information is combined with a medical visualization platform to visualize the shape sensing information together with medical images and post-processing results like 3D models, vessel graphs, or segmentation results. The framework has a modular nature to use it for various medical applications like catheter or needle based interventions. The technology has potential in the medical area as it is MR-compatible and can easily be integrated in catheters and needles due to its small size.

  8. Polymer optical fiber large strain sensing technology based on bending loss

    Science.gov (United States)

    You, Qian; Huang, Yin-guo; Lin, Yu-chi

    2011-11-01

    Based on the bending loss theory of polymer optical fiber, mathematical model of polymer optical fiber large strain sensing is established. Three different polymer optical fiber large strain sensitive structures are designed. And a corresponding intensity modulated polymer optical fiber large strain sensing system is established. The different aspects of properties of three designed sensitive structures are researched and compared by the means of ANSYS software simulation and experimental system. Experimental results show that the designed sensor of b-type structure is a large strain sensor, which has good performance. The b-type sensor's strain measurement range has up to 20%, moreover, its non-linear error is approximate 1.4%, and the system has advantages of high sensitivity.

  9. Single-frequency linear cavity erbium-doped fiber laser for fiber-optic sensing applications

    International Nuclear Information System (INIS)

    We report a short-cavity fiber laser configured with a high-concentration erbium-doped fiber with stable single-frequency output. The fiber laser utilized a fiber Bragg grating inscribed into a piece of polarization-maintaining optical fiber as the output coupler to ensure a stable single frequency laser output. The polarization-maintaining optical fiber used in the output coupler is intended to provide the linearly polarized single-frequency laser output. The fiber laser had a maximum hundreds of micron-Watt level power output pumped by a fiber pigtailed laser diode working at 980 nm. Mode hopping phenomenon was eliminated in such a short-cavity fiber laser. Laser frequency stability less than 400 MHz over 10 minutes was obtained

  10. An Implantable Neural Sensing Microsystem with Fiber-Optic Data Transmission and Power Delivery

    OpenAIRE

    Yoon-Kyu Song; Nurmikko, Arto V.; Mingyu Kang; Sunmee Park; David A. Borton

    2013-01-01

    We have developed a prototype cortical neural sensing microsystem for brain implantable neuroengineering applications. Its key feature is that both the transmission of broadband, multichannel neural data and power required for the embedded microelectronics are provided by optical fiber access. The fiber-optic system is aimed at enabling neural recording from rodents and primates by converting cortical signals to a digital stream of infrared light pulses. In the full microsystem whose performa...

  11. Fiber-Optic Sensing System: Overview, Development and Deployment in Flight at NASA

    Science.gov (United States)

    Chan, Hon Man; Parker, Allen R.; Piazza, Anthony; Richards, W. Lance

    2015-01-01

    An overview of the research and technological development of the fiber-optic sensing system (FOSS) at the National Aeronautics and Space Administration Armstrong Flight Research Center (NASA AFRC) is presented. Theory behind fiber Bragg grating (FBG) sensors, as well as interrogation technique based on optical frequency domain reflectometry (OFDR) is discussed. Assessment and validation of FOSS as an accurate measurement tool for structural health monitoring is realized in the laboratory environment as well as large-scale flight deployment.

  12. A reflection-based localized surface plasmon resonance fiber-optic probe for biochemical sensing

    OpenAIRE

    Lin, Yongbin; Zou, Yang; Lindquist, Robert G.

    2011-01-01

    We report the fabrication and characterization of an optical fiber biochemical sensing probe based on localized surface plasmon resonance (LSPR) and spectra reflection. Ordered array of gold nanodots was fabricated on the optical fiber end facet using electron-beam lithography (EBL). We experimentally demonstrated for the first time the blue shift of the LSPR scattering spectrum with respected to the LSPR extinction spectrum, which had been predicted theoretically. High sensitivity [195.72 nm...

  13. Electrically insulated sensing of respiratory rate and heartbeat using optical fibers.

    Science.gov (United States)

    Suaste-Gómez, Ernesto; Hernández-Rivera, Daniel; Sánchez-Sánchez, Anabel S; Villarreal-Calva, Elsy

    2014-01-01

    Respiratory and heart rates are among the most important physiological parameters used to monitor patients' health. It is important to design devices that can measure these parameters without risking or altering the subject's health. In this context, a novel sensing method to monitor simultaneously the heartbeat and respiratory rate signals of patients within an electrically safety environment was developed and tested. An optical fiber-based sensor was used in order to detect two optical phenomena. Photo-plethysmography and the relation between bending radius and attenuation of optical fiber were coupled through a single beam light traveling along this fiber. PMID:25405510

  14. Electrically Insulated Sensing of Respiratory Rate and Heartbeat Using Optical Fibers

    Directory of Open Access Journals (Sweden)

    Ernesto Suaste-Gómez

    2014-11-01

    Full Text Available Respiratory and heart rates are among the most important physiological parameters used to monitor patients’ health. It is important to design devices that can measure these parameters without risking or altering the subject’s health. In this context, a novel sensing method to monitor simultaneously the heartbeat and respiratory rate signals of patients within an electrically safety environment was developed and tested. An optical fiber-based sensor was used in order to detect two optical phenomena. Photo-plethysmography and the relation between bending radius and attenuation of optical fiber were coupled through a single beam light traveling along this fiber.

  15. Refractive index sensing using V-shaped polymer optical fibers

    Science.gov (United States)

    Lee, Heeyoung; Hayashi, Neisei; Mizuno, Yosuke; Nakamura, Kentaro

    2015-11-01

    Although polymer optical fiber (POF) tapers with high flexibility have been used to measure the refractive indices (RIs) of liquids, their fabrication have caused some inconvenience including the need to use external heat sources or chemicals. Here, as an alternative, we develop a simple, secure, and low-cost method of measuring RIs of liquids using V-shaped bent POFs. When the bending angle is 120° (experimentally optimized), with increasing RI, the transmitted power increases almost linearly with a dependence coefficient of approximately 210 dB/RI unit.

  16. An optical fiber sensing technique for temperature distribution measurements in microwave heating

    Science.gov (United States)

    Wada, Daichi; Sugiyama, Jun-ichi; Zushi, Hiroaki; Murayama, Hideaki

    2015-08-01

    We introduce an optical fiber sensing technique that can measure the temperature distributions along a fiber during microwave heating. We used a long-length fiber Bragg grating (FBG) as an electromagnetic-immune sensor and interrogated temperature distributions along the FBG by an optical frequency domain reflectometry. Water in a glass tube with a length of 820?mm was heated in a microwave oven, and its temperature distribution along the glass tube was measured using the sensing system. The temperature distribution was obtained in 5?mm intervals. Infrared radiometry was also used to compare the temperature measurement results. Time and spatial variations of the temperature distribution profiles were monitored for several microwave input powers. The results clearly depict inhomogeneous temperature profiles. The applicability and effectiveness of the optical fiber distributed measurement technique in microwave heating are demonstrated.

  17. Characterization of Flexible Copolymer Optical Fibers for Force Sensing Applications

    Directory of Open Access Journals (Sweden)

    Lukas J. Scherer

    2013-09-01

    Full Text Available In this paper, different polymer optical fibres for applications in force sensing systems in textile fabrics are reported. The proposed method is based on the deflection of the light in fibre waveguides. Applying a force on the fibre changes the geometry and affects the wave guiding properties and hence induces light loss in the optical fibre. Fibres out of three different elastic and transparent copolymer materials were successfully produced and tested. Moreover, the influence of the diameter on the sensing properties was studied. The detectable force ranges from 0.05 N to 40 N (applied on 3 cm of fibre length, which can be regulated with the material and the diameter of the fibre. The detected signal loss varied from 0.6% to 78.3%. The fibres have attenuation parameters between 0.16–0.25 dB/cm at 652 nm. We show that the cross-sensitivies to temperature, strain and bends are low. Moreover, the high yield strength (0.0039–0.0054 GPa and flexibility make these fibres very attractive candidates for integration into textiles to form wearable sensors, medical textiles or even computing systems.

  18. Chalcogenide glass fibers: Optical window tailoring and suitability for bio-chemical sensing

    Science.gov (United States)

    Lucas, Pierre; Coleman, Garrett J.; Jiang, Shibin; Luo, Tao; Yang, Zhiyong

    2015-09-01

    Glassy materials based on chalcogen elements are becoming increasingly prominent in the development of advanced infrared sensors. In particular, infrared fibers constitute a desirable sensing platform due to their high sensitivity and versatile remote collection capabilities for in-situ detection. Tailoring the transparency window of an optical material to the vibrational signature of a target molecule is important for the design of infrared sensor, and particularly for fiber evanescent wave spectroscopy. Here we review the basic principles and recent developments in the fabrication of chalcogenide glass infrared fibers for application as bio-chemical sensors. We emphasize the challenges in designing materials that combine good rheological properties with chemical stability and sufficiently wide optical windows for bio-chemical sensing. The limitation in optical transparency due to higher order overtones of the amorphous network vibrations is established for this family of glasses. It is shown that glasses with wide optical window suffer from higher order overtone absorptions. Compositional engineering with heavy elements such as iodine is shown to widen the optical window but at the cost of lower chemical stability. The optical attenuations of various families of chalcogenide glass fibers are presented and weighed for their applications as chemical sensors. It is then shown that long-wave infrared fibers can be designed to optimize the collection of selective signal from bio-molecules such as cells and tissues. Issues of toxicity and mechanical resistance in the context of bio-sensing are also discussed.

  19. Erbium doped optical fiber lasers for magnetic field sensing

    Science.gov (United States)

    Nascimento, I. M.; Baptista, J. M.; Jorge, P. A. S.; Cruz, J. L.; Andrés, M. V.

    2015-09-01

    In this work two erbium doped optical fiber laser configurations for magnetic field measurement are implemented and compared. The first laser is set-up in a loop configuration and requires only a single FBG (Fiber Bragg Grating), acting as mirror. A second laser employs a simpler linear cavity configuration but requires two FBGs with spectral overlap to form the laser cavity. A bulk magnetostrictive material made of Terfenol-D is attached to the laser FBGs enabling modulation of its operation wavelength by the magnetic field. Moreover, a passive interferometer was developed to demodulate the AC magnetic field information where the corresponding demodulation algorithms were software based. Both configurations are tested and compared with the results showing different sensitivities and resolutions. Better performance was accomplished with the double FBGs linear cavity configuration with a resolution of 0.05 mTRMS in the range of 8 to 16 mTRMS. For the same range the loop configuration attained a resolution of 0.48 mTRMS.

  20. Assessment of fiber optic sensors and other advanced sensing technologies for nuclear power plants

    International Nuclear Information System (INIS)

    As a result of problems such as calibration drift in nuclear plant pressure sensors and the recent oil loss syndrome in some models of Rosemount pressure transmitters, the nuclear industry has become interested in fiber optic pressure sensors. Fiber optic sensing technologies have been considered for the development of advanced instrumentation and control (I ampersand C) systems for the next generation of reactors and in older plants which are retrofitted with new I ampersand C systems. This paper presents the results of a six-month Phase I study to establish the state-of-the-art in fiber optic pressure sensing. This study involved a literature review, contact with experts in the field, an industrial survey, a site visit to a fiber optic sensor manufacturer, and laboratory testing of a fiber optic pressure sensor. The laboratory work involved both static and dynamic performance tests. This initial Phase I study has recently been granted a two-year extension by the U.S. Nuclear Regulatory Commission (NRC). The next phase will evaluate fiber optic pressure sensors in specific nuclear plant applications in addition to other advanced methods for monitoring critical nuclear plant equipment

  1. Assessment of fiber optic sensors and other advanced sensing technologies for nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Hashemian, H.M. [Analysis and Measurement Services Corporation, Knoxville, TN (United States)

    1996-03-01

    As a result of problems such as calibration drift in nuclear plant pressure sensors and the recent oil loss syndrome in some models of Rosemount pressure transmitters, the nuclear industry has become interested in fiber optic pressure sensors. Fiber optic sensing technologies have been considered for the development of advanced instrumentation and control (I&C) systems for the next generation of reactors and in older plants which are retrofitted with new I&C systems. This paper presents the results of a six-month Phase I study to establish the state-of-the-art in fiber optic pressure sensing. This study involved a literature review, contact with experts in the field, an industrial survey, a site visit to a fiber optic sensor manufacturer, and laboratory testing of a fiber optic pressure sensor. The laboratory work involved both static and dynamic performance tests. This initial Phase I study has recently been granted a two-year extension by the U.S. Nuclear Regulatory Commission (NRC). The next phase will evaluate fiber optic pressure sensors in specific nuclear plant applications in addition to other advanced methods for monitoring critical nuclear plant equipment.

  2. Optically heated fiber Bragg grating in active fibers for low temperature sensing application

    Science.gov (United States)

    Qi, Lin; Jin, Long; Guan, Bai-Ou

    2013-09-01

    Optically heated fiber Bragg gratings due to the absorption over the fiber core in rare-earth doped fibers are experimentally demonstrated. Bragg wavelength variations with pump power are measured for different fibers. We found that the Er/Yb-codoped fiber presents the strongest thermal effect, due to the high absorption. A maximum wavelength shift of 1.34 nm can be obtained when the 980 nm pump power is 358 mW under room temperature, suggesting the fiber is heated up to over 100 °C. Furthermore, the thermal effect is enhanced by pumping the surrounding air to close to vacuum. A wavelength shift of 1.69 nm is attained, due to the weakened ability of heat transfer at the silica-air interface. The optical heating presents a very short response time and can found applications in low temperature circumstances.

  3. Fiber-optic Raman sensing of cell proliferation probes and molecular vibrations: Brain-imaging perspective

    Science.gov (United States)

    Doronina-Amitonova, Lyubov V.; Fedotov, Il'ya V.; Ivashkina, Olga I.; Zots, Marina A.; Fedotov, Andrei B.; Anokhin, Konstantin V.; Zheltikov, Aleksei M.

    2012-09-01

    Optical fibers are employed to sense fingerprint molecular vibrations in ex vivo experiments on the whole brain and detect cell proliferation probes in a model study on a quantitatively controlled solution. A specifically adapted spectral filtering procedure is shown to allow the Raman signal from molecular vibrations of interest to be discriminated against the background from the fiber, allowing a highly sensitive Raman detection of the recently demonstrated EdU (5-ethynyl-2'-deoxyuridine) labels of DNA synthesis in cells.

  4. Hierarchical fiber-optic-based sensing system: impact damage monitoring of large-scale CFRP structures

    International Nuclear Information System (INIS)

    This study proposes a novel fiber-optic-based hierarchical sensing concept for monitoring randomly induced damage in large-scale composite structures. In a hierarchical system, several kinds of specialized devices are hierarchically combined to form a sensing network. Specifically, numerous three-dimensionally structured sensor devices are distributed throughout the whole structural area and connected with an optical fiber network through transducing mechanisms. The distributed devices detect damage, and the fiber-optic network gathers the damage signals and transmits the information to a measuring instrument. This study began by discussing the basic concept of a hierarchical sensing system through comparison with existing fiber-optic-based systems, and an impact damage detection system was then proposed to validate the new concept. The sensor devices were developed based on comparative vacuum monitoring (CVM), and Brillouin-based distributed strain measurement was utilized to identify damaged areas. Verification tests were conducted step-by-step, beginning with a basic test using a single sensor unit, and, finally, the proposed monitoring system was successfully verified using a carbon fiber reinforced plastic (CFRP) fuselage demonstrator. It was clearly confirmed that the hierarchical system has better repairability, higher robustness, and a wider monitorable area compared to existing systems

  5. Advanced Fiber Optic-Based Sensing Technology for Unmanned Aircraft Systems

    Science.gov (United States)

    Richards, Lance; Parker, Allen R.; Piazza, Anthony; Ko, William L.; Chan, Patrick; Bakalyar, John

    2011-01-01

    This presentation provides an overview of fiber optic sensing technology development activities performed at NASA Dryden in support of Unmanned Aircraft Systems. Examples of current and previous work are presented in the following categories: algorithm development, system development, instrumentation installation, ground R&D, and flight testing. Examples of current research and development activities are provided.

  6. Remote Management for Multipoint Sensing Systems Using Hetero-Core Spliced Optical Fiber Sensors

    OpenAIRE

    Lee See Goh; Yuji Anoda; Watanabe Kazuhiro; Norihiko Shinomiya

    2013-01-01

    This paper describes the design and experimental verification of a multipoint sensing system with hetero-core spliced optical fiber sensors and its remote management using an internet-standard protocol. The study proposes two different types of design and conducts experiments to verify those systems' feasibility. In order to manage the sensing systems remotely, the management method uses a standard operation and maintenance protocol for internet: the Simple Network Management Protocol is prop...

  7. A scalable pathway to nanostructured sapphire optical fiber for evanescent-field sensing and beyond

    Science.gov (United States)

    Chen, Hui; Tian, Fei; Kanka, Jiri; Du, Henry

    2015-03-01

    We here report an innovative and scalable strategy of transforming a commercial unclad sapphire optical fiber to an all-alumina nanostructured sapphire optical fiber (NSOF). The strategy entails fiber coating with metal aluminum followed by anodization to form alumina cladding of highly organized pore channel structure. Through experiments and numerical simulation, we demonstrate the utility and benefit of NSOF, analogous to all-silica microstructured optical fiber, for evanescent-field surface-enhanced Raman scattering (SERS) measurements. We experimentally reveal the feasibility of Ag nanoparticles (NPs)-enabled NSOF SERS sensing of 10-6 M Rhodamine 6G (R6G) after thermal treatment at 500 °C for 6 h by taking advantage of porous anodic aluminum oxide (AAO) structure to stabilize the Ag NPs. We show, via numerical simulations, that AAO cladding significantly increases the evanescent-field overlap, lower porosity of AAO results in higher evanescent-field overlap, and optimized AAO nanostructure yields greater SERS enhancement.

  8. Fiber Optic Sensing Monitors Strain and Reduces Costs

    Science.gov (United States)

    2008-01-01

    In applications where stress on a structure may vary widely and have an unknown impact on integrity, a common engineering strategy has been overbuilding to ensure a sufficiently robust design. While this may be appropriate in applications where weight concerns are not paramount, space applications demand a bare minimum of mass, given astronomical per-pound launch costs. For decades, the preferred solution was the tactic of disassembly and investigation between flights. Knowing there must be a better way, Dr. Mark Froggatt, of Langley Research Center, explored alternate means of monitoring stresses and damage to the space shuttle. While a tear-it-apart-and-have-a-look strategy was effective, it was also a costly and time consuming process that risked further stresses through the very act of disassembly and reassembly. An alternate way of monitoring the condition of parts under the enormous stresses of space flight was needed. Froggatt and his colleagues at Langley built an early-warning device to provide detailed information about even minuscule cracks and deformations by etching a group of tiny lines, or grating, on a fiber optic cable five-thousandths of an inch thick with ultraviolet light. By then gluing the fiber to the side of a part, such as a fuel tank, and shining a laser beam down its length, reflected light indicated which gratings were under stress. Inferring this data from measurements in light rather than in bonded gauges saved additional weight. Various shuttle components now employ the ultrasonic dynamic vector stress sensor (UDVSS), allowing stress detection by measuring light beamed from a built-in mini-laser. By measuring changes in dynamic directional stress occurring in a material or structure, and including phase-locked loop, synchronous amplifier, and contact probe, the UDVSS proved especially useful among manufacturers of aerospace and automotive structures for stress testing and design evaluation. Engineers could ensure safety in airplanes and spaceships with a narrower, not overbuilt, margin of safety. For this development, in 1997, Discover Magazine named Froggatt a winner in the "Eighth Annual Awards for Technological Innovation" from more than 4,000 entries.

  9. Research of AGC technology in a digital optical fiber sensing system with PGC modulation and demodulation

    Science.gov (United States)

    Tang, Jianfeng; Xiong, Shuidong; Zhang, Yan

    2014-11-01

    The magnitude of light intensity on the photo-to-electric detector fluctuates all the time in an optic fiber sensing system, because of the influence of various factors in the fiber optic sensing system and from the external environment. As a result of the excessive intensity, the electric signal will be overload after the amplifier circuit with constant enlargement factor, and when the light intensity becames too small, it will reduce the signal-to-noise ratio of the electric signal. Therefore, it is necessary to introduce an automatic gain control (AGC) module into the system, which can insure the electric signal in a reasonable magnitude. In order to solve the problem of optic intensity fluctuating in the optical fiber sensing system with PGC modulation and demodulation, in this paper, firstly, it is analyzed that the impact of different magnitudes of interferential intensity to the PGC demodulation in theory. Secondly, a reasonable control method is put forward and an AGC module based on the AD602 chip is designed and produced. Finally, it is proved that the optic fiber sensor system with an AGC module has strong ability to resist fluctuation of light intensity within 40dB.

  10. Application of a distributed optical fiber sensing technique in monitoring the stress of precast piles

    International Nuclear Information System (INIS)

    Due to its ability in providing long distance, distributed sensing, the optical fiber sensing technique based on a Brillouin optical time domain reflectometer (BOTDR) has a unique advantage in monitoring the stability and safety of linear structures. This paper describes the application of a BOTDR-based technique to measure the stress within precast piles. The principle behind the BOTDR and the embedding technique for the sensing optical fiber in precast piles is first introduced, and then the analysis method and deformation and stress calculation based on distributed strain data are given. Finally, a methodology for using a BOTDR-based monitoring workflow for in situ monitoring of precast piles, combined with a practical example, is introduced. The methodology requires implantation of optical fibers prior to pile placement. Field experimental results show that the optical fiber implantation method with slotting, embedding, pasting and jointing is feasible, and have accurately measured the axial force, side friction, end-bearing resistance and bearing feature of the precast pile according to the strain measuring data. (paper)

  11. Distributed Long-Gauge Optical Fiber Sensors Based Self-Sensing FRP Bar for Concrete Structure.

    Science.gov (United States)

    Tang, Yongsheng; Wu, Zhishen

    2016-01-01

    Brillouin scattering-based distributed optical fiber (OF) sensing technique presents advantages for concrete structure monitoring. However, the existence of spatial resolution greatly decreases strain measurement accuracy especially around cracks. Meanwhile, the brittle feature of OF also hinders its further application. In this paper, the distributed OF sensor was firstly proposed as long-gauge sensor to improve strain measurement accuracy. Then, a new type of self-sensing fiber reinforced polymer (FRP) bar was developed by embedding the packaged long-gauge OF sensors into FRP bar, followed by experimental studies on strain sensing, temperature sensing and basic mechanical properties. The results confirmed the superior strain sensing properties, namely satisfied accuracy, repeatability and linearity, as well as excellent mechanical performance. At the same time, the temperature sensing property was not influenced by the long-gauge package, making temperature compensation easy. Furthermore, the bonding performance between self-sensing FRP bar and concrete was investigated to study its influence on the sensing. Lastly, the sensing performance was further verified with static experiments of concrete beam reinforced with the proposed self-sensing FRP bar. Therefore, the self-sensing FRP bar has potential applications for long-term structural health monitoring (SHM) as embedded sensors as well as reinforcing materials for concrete structures. PMID:26927110

  12. Design and Fabrication of Fiber-Optic Nanoprobes for Optical Sensing

    OpenAIRE

    Zhang Yan; Dhawan Anuj; Vo-Dinh Tuan

    2010-01-01

    Abstract This paper describes the design and fabrication of fiber-optic nanoprobes developed for optical detection in single living cells. It is critical to fabricate probes with well-controlled nanoapertures for optimized spatial resolution and optical transmission. The detection sensitivity of fiber-optic nanoprobe depends mainly on the extremely small excitation volume that is determined by the aperture sizes and penetration depths. We investigate the angle dependence of the aperture in sh...

  13. Electrically Insulated Sensing of Respiratory Rate and Heartbeat Using Optical Fibers

    OpenAIRE

    Ernesto Suaste-Gómez; Daniel Hernández-Rivera; Sánchez-Sánchez, Anabel S.; Elsy Villarreal-Calva

    2014-01-01

    Respiratory and heart rates are among the most important physiological parameters used to monitor patients’ health. It is important to design devices that can measure these parameters without risking or altering the subject’s health. In this context, a novel sensing method to monitor simultaneously the heartbeat and respiratory rate signals of patients within an electrically safety environment was developed and tested. An optical fiber-based sensor was used in order to detect two optical phen...

  14. Fiber-optic ultrasonic sensing systems using PS-FBG for damage monitoring in composite materials

    Science.gov (United States)

    Okabe, Yoji; Wu, Qi

    2015-07-01

    Fiber-optic ultrasonic sensing systems have been developed for structural health monitoring of composite structures by introduction of phase-shifted fiber Bragg gratings (PS-FBGs). The systems can achieve the compatibility of high sensitivity and broadband performance. First, PS-FBG balanced sensing system was developed and succeeded in detection of small acoustic emission signals of composite laminates. Next, erbium fiber ring laser sensing system with inbuilt PS-FBG was developed. This system has high robustness due to its self-adjustment function for environmental disturbances and achieved much higher sensitivity and ultra-broadband respondency than piezoelectric ceramic sensors. These systems have large potential to realize the ultrasonic SHM.

  15. A hydrostatic leak test for water pipeline by using distributed optical fiber vibration sensing system

    Science.gov (United States)

    Wu, Huijuan; Sun, Zhenshi; Qian, Ya; Zhang, Tao; Rao, Yunjiang

    2015-07-01

    A hydrostatic leak test for water pipeline with a distributed optical fiber vibration sensing (DOVS) system based on the phase-sensitive OTDR technology is studied in this paper. By monitoring one end of a common communication optical fiber cable, which is laid in the inner wall of the pipe, we can detect and locate the water leakages easily. Different apertures under different pressures are tested and it shows that the DOVS has good responses when the aperture is equal or larger than 4 mm and the inner pressure reaches 0.2 Mpa for a steel pipe with DN 91cm×EN 2cm.

  16. Fiber optic sensing system for monitoring of coal waste piles in combustion

    Science.gov (United States)

    Viveiros, D.; Ribeiro, J.; Carvalho, J. P.; Ferreira, J.; Pinto, A. M. R.; Perez-Herrera, R. A.; Diaz, S.; Lopez-Gil, A.; Dominguez-Lopez, A.; Esteban, O.; Martins, H. F.; Martin-Lopez, S.; Baierl, H.; Auguste, J.-L.; Jamier, R.; Rougier, S.; Santos, J. L.; Flores, D.; Roy, P.; González-Herráez, M.; López-Amo, M.; Baptista, J. M.

    2014-05-01

    The combustion of coal wastes resulting from mining is of particular environmental concern and therefore the importance of the proper management involving real-time assessment of their status and identification of probable evolution scenarios is recognized. Continuous monitoring of combustion temperature and emission levels of certain gases opens the possibility to plan corrective actions to minimize their negative impact in the surroundings. Optical fiber technology is well-suited to this purpose and in this work it is described the main attributes of a fiber optic sensing system projected to gather data on distributed temperature and gas emission in these harsh environments.

  17. Coherence sensing of time-addressed optical-fiber sensors illuminated by a multimode laser diode.

    Science.gov (United States)

    Santos, J L; Jackson, D A

    1991-12-01

    A reflective array of optical-fiber sensors multiplexed in time and with their status read using coherence sensing associated with directly modulated multimode laser-diode illumination is investigated. Sensor sensitivity as determined by primary noise sources is evaluated and numerical results are presented. The concept is demonstrated with two all-fiber Michelson interferometers and applied to the measurement of periodic and quasi-static parameters. It is shown that the effect of feedback light into the laser cavity on the level of the system noise floor is negligible, making unnecessary the use of source optical isolation. PMID:20717322

  18. Development of optical fibers for mid-infrared sensing: state of the art and recent achievements

    Science.gov (United States)

    Bureau, Bruno; Boussard-Plédel, Catherine; Troles, Johann; Nazabal, Virginie; Adam, Jean-Luc; Doualan, Jean-Louis; Braud, Alain; Camy, Patrice; Lucas, Pierre; Brilland, Laurent; Quetel, Lionel; Tariel, Hugues

    2015-05-01

    Chalcogenide glass fibers are matchless devices to collect mi-infrared signal. Depending on the spectroscopic strategy, different kind of optical fibers have been developed during the past 10 years. The first fibers have been fabricated from selenide glasses to implement Fiber Evanescent Wave Spectroscopy (FEWS). It is an efficient way to collect optical spectra in situ, in real time and even, in the future, in vivo. Thanks to selenide glass fibers, it is possible to record such spectra on the mid-infrared range from 2 to 11 ?m. This working window gives access to the fundamental vibration band of most of biological molecules and numerous multi-disciplinary works have been led in biology and medicine. New glasses, only based on tellurium, have been recently developed, initially in the frame of the Darwin mission led by the European Space Agency (ESA). These glasses transmit light further toward the farinfrared and permit to reach the absorption band of CO2 located at 15 ?m as requested by the ESA. Moreover, these telluride glass fiber are also very interesting for FEWS and medical application. Indeed, they give access to the mid-infrared signal of biomolecules beyond 11 ?m, where classical selenide glass fibers are blind. Alternatively, in order to fight against global warning, some optical fibers have been developed for the monitoring of the CO2 stored into geological storage area underground. These fibers were doped with Dy3+ which emits a broad fluorescent band embedding the CO2 absorption band at 4.3 ?m. thus, these fibers are used both to transmit light and as secondary sources in the mid-infrared. To conclude, original microstructurated fibers have also been used for mid-infrared sensing. They exhibit a nice sensitivity compared to classical chalcogenide glass fibers.

  19. Sensing characteristics of clad-modified with nanocrystalline metal oxide fiber optic gas sensor

    Science.gov (United States)

    Sastikumar, D.; Renganathan, B.

    2014-11-01

    Clad-modified with nanocrystalline metal oxide fiber optic gas sensors have been proposed for ambient temperature operation. The sensor output light intensity either increases or decreases when the gas concentration is increased. Study shows that optical properties of metal-oxides with air medium influence the gas sensing. Absorption characteristics of nanocrystalline metal oxides ( ZnO, Sm2O3 and Ce doped ZnO etc., ) in air, methanol, ethanol and ammonia are analyzed as well as their effect on gas sensing.

  20. Fiber Optic Shape Sensing for Tethered Marsupial Rovers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Luna Innovations Incorporated is proposing to design, build, and test a shape, length, and tension sensing tether for robotic exploration and sample-gathering...

  1. Fiber Optic Shape Sensing for Tethered Marsupial Rovers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Building upon the successful proof of concept work in Phase I, Luna Innovations Incorporated is proposing to design, build, and test a sensing tether for marsupial...

  2. Ce-doped SiO2 optical fibers for remote radiation sensing and measurement

    Science.gov (United States)

    Chiodini, Norberto; Vedda, Anna; Fasoli, Mauro; Moretti, Federico; Lauria, Alessandro; Cantone, Marie Claire; Veronese, Ivan; Tosi, Giampiero; Brambilla, Marco; Cannillo, Barbara; Mones, Eleonora; Brambilla, Gilberto; Petrovich, Marco

    2009-05-01

    Scintillating materials, able to convert energy of ionizing radiation into light in the visible-UV interval, are presently used in a wide class of applications such as medical imaging, industrial inspection, security controls and high energy physics detectors. In the last few years we studied and developed a new radiation sensor based on silica-glass fiber-optic technology. In its simplest configuration such device is composed by a short portion (about 10 mm) of scintillating fiber coupled to a photomultiplier through a suitably long passive silica fiber. In this work, we present new results concerning the characterization of silica based Ce and Eu doped fibers glasses obtained by a modified sol-gel method and drawn by a conventional drawing tower for optical fibers. The radio-luminescence of Eu doped fibers is rather weak; moreover it displays a marked sensitivity increase during subsequent irradiations, preventing the use of such fibers in dosimetry. On the other hand Ce-doped fibers show very high radiation hardness, signal stability and reproducibility, and high sensitivity to radiations with energies from 10 keV to several tens of MeV. Numerous tests with photons (X and gamma rays), electrons, and protons have already been successfully performed. At the early stage of its market introduction it is the smallest radiation sensor, also compared to MOSFET and diode technology and it appears to be the ideal choice for in vivo measurements in medical field or remote sensing.

  3. Ratiometric optical fiber sensor for dual sensing of copper ion and dissolved oxygen.

    Science.gov (United States)

    Chu, Cheng-Shane; Chuang, Chih-Yung

    2015-12-20

    This paper develops a new ratiometric optical dual sensor for Cu2+ ions and dissolved oxygen (DO) incorporating a sol-gel matrix doped with palladium tetrakis pentafluorophenyl porphine as the oxygen-sensitive material, CdSe quantum dots as the Cu2+ ion-sensing material, and 7-amino-4-trifluoromethyl coumarin as the Cu2+/DO practically independent fluorescent dye. The feasibility of coating an optical fiber with the sensing film to fabricate a ratiometric optical fiber dual sensor is investigated. Using an LED with a central wavelength of 405 nm as an excitation source, it is shown that the emission wavelengths of the Cu2+ ion-sensitive, DO-sensitive dye and the reference dye have no spectral overlap and therefore permit Cu2+ ion and DO concentration to be measured using a ratiometric-based method. The ratiometric optical fiber dual sensor has been tested with regard to monitoring different Cu2+ ion (0-10 ?M) and DO concentrations (0-38 mg/L). The results show that the luminescence properties of the Cu2+ ion sensor are independent of the presence of the oxygen sensor and have a uniquely good linear response in the 0-10 ?M range. The proposed ratiometric sensing approach presented in this study has the advantage of suppressing spurious fluctuations in the intensity of the excitation source. PMID:26837033

  4. Comprehensive long distance and real-time pipeline monitoring system based on fiber optic sensing

    Energy Technology Data Exchange (ETDEWEB)

    Nikles, Marc; Ravet, Fabien; Briffod, Fabien [Omnisens S.A., Morges (Switzerland)

    2009-07-01

    An increasing number of pipelines are constructed in remote regions affected by harsh environmental conditions. These pipeline routes often cross mountain areas which are characterized by unstable grounds and where soil texture changes between winter and summer increase the probability of hazards. Due to the long distances to be monitored and the linear nature of pipelines, distributed fiber optic sensing techniques offer significant advantages and the capability to detect and localize pipeline disturbance with great precision. Furthermore pipeline owner/operators lay fiber optic cable parallel to transmission pipelines for telecommunication purposes and at minimum additional cost monitoring capabilities can be added to the communication system. The Brillouin-based Omnisens DITEST monitoring system has been used in several long distance pipeline projects. The technique is capable of measuring strain and temperature over 100's kilometers with meter spatial resolution. Dedicated fiber optic cables have been developed for continuous strain and temperature monitoring and their deployment along the pipeline has enabled permanent and continuous pipeline ground movement, intrusion and leak detection. This paper presents a description of the fiber optic Brillouin-based DITEST sensing technique, its measurement performance and limits, while addressing future perspectives for pipeline monitoring. (author)

  5. Fiber Loop Ringdown — a Time-Domain Sensing Technique for Multi-Function Fiber Optic Sensor Platforms: Current Status and Design Perspectives

    OpenAIRE

    Chuji Wang

    2009-01-01

    Fiber loop ringdown (FLRD) utilizes an inexpensive telecommunications light source, a photodiode, and a section of single-mode fiber to form a uniform fiber optic sensor platform for sensing various quantities, such as pressure, temperature, strain, refractive index, chemical species, biological cells, and small volume of fluids. In FLRD, optical losses of a light pulse in a fiber loop induced by changes in a quantity are measured by the light decay time constants. FLRD measures time to detec...

  6. OptaSense distributed acoustic and seismic sensing using COTS fiber optic cables for infrastructure protection and counter terrorism

    Science.gov (United States)

    Duckworth, Gregory L.; Ku, Emery M.

    2013-06-01

    The OptaSense® Distributed Acoustic Sensing (DAS) technology can turn any cable with single-mode optical fiber into a very large and densely sampled acoustic/seismic sensor array—covering up to a 50 km aperture per system with "virtual" sensor separations as small as 1 meter on the unmodified cable. The system uses Rayleigh scattering from the imperfections in the fiber to return the optical signals measuring local fiber strain from seismic or air and water acoustic signals. The scalable system architecture can provide border monitoring and high-security perimeter and linear asset protection for a variety of industries—from nuclear facilities to oil and gas pipelines. This paper presents various application architectures and system performance examples for detection, localization, and classification of personnel footsteps, vehicles, digging and tunneling, gunshots, aircraft, and earthquakes. The DAS technology can provide a costeffective alternative to unattended ground sensors and geophone arrays, and a complement or alternative to imaging and radar sensors in many applications. The transduction, signal processing, and operator control and display technology will be described, and performance examples will be given from research and development testing and from operational systems on pipelines, critical infrastructure perimeters, railroads, and roadways. Potential new applications will be discussed that can take advantage of existing fiber-optic telecommunications infrastructure as "the sensor"—leading to low-cost and high-coverage systems.

  7. Analysis of the acoustic response in water and sand of different fiber optic sensing cables

    Science.gov (United States)

    Hofmann, Joachim; Facchini, Massimo; Lowell, Mark

    2015-05-01

    Distributed Acoustic Sensing (DAS) is a highly promising technology to efficiently monitor assets for energy production and transportation, both off- and on-shore, such as boreholes, pipelines and risers. The aim of the hereby-presented measurements is to evaluate the sensitivity of the different optical fiber cables to acoustic signals in sand and water, independently from the DAS read-out unit type and manufacturer. Acoustic sensing cables specifically designed by BRUGG Cables are characterized and compared to standard telecommunication cables. The spectral response of each cable was quantified using an all-fiber Mach-Zehnder interferometer. The response was also measured with calibrated microphones in order to convert the measurements into absolute physical units (Pascal). The measurement campaign is part of an investigation program for a reliable DAS system, which comprises the sensing cable (including installation procedure), the interrogator unit and suitable software.

  8. Research and application of optical fiber sensing technology in wireless temperature monitoring of switchgear

    Science.gov (United States)

    Gan, Weibing; Zhang, Cui

    2013-09-01

    In view of the high voltage, strong magnetic field environment of high voltage switchgear, the isolation contact temperature measurement scheme of optical fiber based on wireless sensor technology realizes the contact temperature monitoring of high-voltage switchgear. In this scheme, good thermal conductivity and insulation ceramic materials are selected as outer jacket material sensing probe, and the program has a good solution to the problem of high and low voltage isolation; Combination of optical fiber composite insulator for wireless sensing, solves the problem of high voltage insulation, but also to avoid the "creeping" phenomenon due to dust. The package structure and reasonable installation solve the cross sensitivity of strain. Application shows that the precision of temperature measurement of the system can reach ± 0.5 ° and can work in a variety of harsh environment. It can improve the reliability of the operation of electrical equipment significantly and has considerable practical value for the normal operation of the whole power system.

  9. A reflection-based localized surface plasmon resonance fiber-optic probe for biochemical sensing.

    Science.gov (United States)

    Lin, Yongbin; Zou, Yang; Lindquist, Robert G

    2011-01-01

    We report the fabrication and characterization of an optical fiber biochemical sensing probe based on localized surface plasmon resonance (LSPR) and spectra reflection. Ordered array of gold nanodots was fabricated on the optical fiber end facet using electron-beam lithography (EBL). We experimentally demonstrated for the first time the blue shift of the LSPR scattering spectrum with respected to the LSPR extinction spectrum, which had been predicted theoretically. High sensitivity [195.72 nm/refractive index unit (RIU)] of this sensor for detecting changes in the bulk refractive indices has been demonstrated. The label-free affinity bio-molecules sensing capability has also been demonstrated using biotin and streptavidin as the receptor and the analyte. PMID:21412453

  10. Seepage and settlement monitoring for earth embankment dams using fully distributed sensing along optical fibers

    Science.gov (United States)

    Zhu, P. Y.; Zhou, Y.; Thévenaz, Luc; Jiang, G. L.

    2008-12-01

    A method for seepage and settlement monitoring in earth embankment dams using fully distributed sensing along optical fibres is proposed. A model is developed for simulating and monitoring seepage and settlement systems. This model relates the strains and the temperature changes to the fiber Brillouin gain spectrum in the embankment dam embedding the optical fiber sensors. The model consists of two parts. Submodel 1 addresses the simulation of seepage inside the embankment dam. Submodel 2 relates the measurement of the fiber Brillouin gain spectrum to the changes in temperature and strain inside the embankment dam. Both the changes in temperature and strain during the process are used to reveal serious seepages and settlements occurring inside the embankment dam. The continuously decreasing temperature curve shows an abrupt dramatic increasing rate, which shows that the change is not caused by the temperature of the seepage water but the strain. In this paper, as an example, a model filled with the soil from Yellow River is built and bare optical fibers are embedded under different soil layers near the seepage path. The simulated seepage flows under various flow rates are monitored using the optical fibers and measured by a DiTeSt -STA202 distributed temperature and strain analyzer. A partial settlement within the embankment dam model is observed.

  11. Sensing nanometric displacement of a micro-/nano-fiber induced by optical forces by use of white light interferometry

    Science.gov (United States)

    Qiu, Weiqia; Huang, Hankai; Yu, Jianhui; Dong, Huazhuo; Chen, Zhe; Lu, Huihui

    2015-07-01

    Sensing the nanometric displacement of a micro-/nano-fiber induced by optical forces is a key technology to study optical forces and optical momentum. When the gap between a micro-/nano-fiber and glass substrate becomes down to micrometer scale or less, a white light interference was observed. The gap changes when optical force arising from the propagating pump light along the micro-/nano-fiber causes a transversal nanometric displacement of a micro-/nanofiber, resulting in movement of the interferometric fringes. Therefore this movement of the interferometric fringes can be used to sense the nanometric displacement of the micro-/nano-fiber induced by optical forces. Experimental results show that the resolutions of this method can reach 7.27nm/pixel for tilted angle 0.8o between the micro-/nano-fiber and substrate. It is concluded that the white light interferometry method is suitable for measuring the weak optical force.

  12. Distributed fiber-optic temperature sensing: recent improvements and Nagra's applications in the Mont Terri URL

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Full text of publication follows: The application of fiber-optic sensors in large experiments in underground rock laboratories (URL) and for monitoring of pilot repositories offers several advantages in contrast to conventional sensors. By means of optical fibers distributed temperature and deformation measurements can be performed without electric or mechanical components at the measurement location reducing the risk of corrosion and sensor failure. As fiber-optic strain sensors are to some extend still in a prototype stage, we focus here on Raman spectra distributed fiber-optic temperature sensing (DTS). In DTS a fiber-optic cable, which is the temperature sensor, is connected to a light reading unit that sends laser-pulses into the fiber. The backscattered light is detected with high temporal resolution. From the two-way-light-travel-time the location of backscattering is determined. For the temperature information the amplitude ratio of the Stokes and anti-Stokes signals is analyzed. The Stokes and anti- Stokes signals are the result of the Raman effect. The ratio of these signals provides a quantity that depends only on the temperature of the fiber at the location of backscatter. With commercial DTS setups it is possible to measure the temperature distribution along several kilometer long cables with a temperature resolution of 0.01 C and a spatial resolution of 1 m. Recent developments in DTS focus on better temperature precision and resolution. This advancement can be achieved by experiment-specific calibration techniques and sensor-layout as well as improved instruments. To realize high spatial resolution (cm range) wrapped fiber-optic cables can be applied. Another promising approach to monitor moisture along a fiber-optic cable installed in unconsolidated material are heatable cables. We will present a selection of the most recent advancements which may improve temperature monitoring in natural and engineered clay-barriers using DTS. In addition, first results and experiences of Nagra's DTS applications in the Mont Terri URL will be presented. Fiber-optic sensors were installed within the Full-Scale Emplacement (FE) Experiment. The FE-experiment is a full-scale heater test also simulating the construction, emplacement and backfilling of a repository tunnel according to the Swiss concept for high level waste. The THM evolution in the host rock (near- and far-field), tunnel lining and the engineered barrier system will be monitored by several hundred conventional sensors. In addition to thermo-resistive conventional temperature sensors fiber-optic cables amend the temperature monitoring. In the host rock 45 m long inclinometer casings are equipped with fiber-optic cables to observe the longitudinal temperature evolution above the tunnel. The temperature distribution at the interface engineered barrier - tunnel lining is planned to be monitored by fiber-optic cables covering the surface of the tunnel lining. The fiber-optics in combination with the conventional temperature sensors will result in detailed insights into non-uniformity of heat transport within the engineered barrier and the host rock caused by spatial and temporal variability of thermal conductivity and therewith saturation and porosity. (authors)

  13. Distributed sensing of hydrocarbon leakage using fiber-optic time domain reflectometry

    International Nuclear Information System (INIS)

    In many industrial areas fast leakage detection and spill locating of environmentally hazardous substances in technical installations with large spatial extension, e.g., chemical plants, pipelines, tanks or waste deposits gains in importance. For a complete and continuous control of such sites distributed chemical sensing is essential. In this paper a new distributed sensor system for fast hydrocarbon leakage detection and localization is presented, which is based on hydrocarbon sensitive optical fibers and optical time domain reflectometry (OTDR). Depending on the used laser pulse width a minimum spatial resolution of 1-5 m is obtained, while the minimum response times are in the 15-30 s range. (orig.)

  14. Self-referencing fiber optic particle plasmon resonance sensing system for real-time biological monitoring.

    Science.gov (United States)

    Wu, Chin-Wei; Chiang, Chang-Yue; Chen, Chien-Hsing; Chiang, Chung-Sheng; Wang, Chih-To; Chau, Lai-Kwan

    2016-01-01

    We present the design and experimental verification of a self-referencing dual-channel fiber optic particle plasmon resonance (FOPPR) sensing system for compensation of thermal and bulk-composition effects as well as nonspecific adsorption in real-time biosensing of complex samples. A theoretical model is first proposed and then a systematic experimental approach is used to verify the model. The sensing system comprises an analysis fiber sensor and a reference fiber sensor in a single microfluidic chip, where the analysis fiber is functionalized with a recognition molecule. The compensation still works even if the surface coverages of gold nanoparticles on the reference and analysis fibers are not exactly the same. The potential of this approach is illustrated by a model biosensing experiment in which the detection of anti-biotin is compensated for bulk refractive index change, nonspecific adsorption and/or color interference, in various sample media. The percent recovery is 103.2% under both the effects of bulk refractive index change and nonspecific adsorption and is 93.9% under both the effects of color interference and nonspecific adsorption, suggesting that the compensation is effective. PMID:26695266

  15. Fiber optic vibration sensor

    Science.gov (United States)

    Dooley, Joseph B. (Harriman, TN); Muhs, Jeffrey D. (Lenoir City, TN); Tobin, Kenneth W. (Harriman, TN)

    1995-01-01

    A fiber optic vibration sensor utilizes two single mode optical fibers supported by a housing with one optical fiber fixedly secured to the housing and providing a reference signal and the other optical fiber having a free span length subject to vibrational displacement thereof with respect to the housing and the first optical fiber for providing a signal indicative of a measurement of any perturbation of the sensor. Damping or tailoring of the sensor to be responsive to selected levels of perturbation is provided by altering the diameter of optical fibers or by immersing at least a portion of the free span length of the vibration sensing optical fiber into a liquid of a selected viscosity.

  16. A Self-Referencing Intensity-Based Fiber Optic Sensor with Multipoint Sensing Characteristics

    Directory of Open Access Journals (Sweden)

    Sang-Jin Choi

    2014-07-01

    Full Text Available A self-referencing, intensity-based fiber optic sensor (FOS is proposed and demonstrated. The theoretical analysis for the proposed design is given, and the validity of the theoretical analysis is confirmed via experiments. We define the measurement parameter, X, and the calibration factor, ?, to find the transfer function, , of the intensity-based FOS head. The self-referencing and multipoint sensing characteristics of the proposed system are validated by showing the measured  and relative error versus the optical power attenuation of the sensor head for four cases: optical source fluctuation, various remote sensing point distances, fiber Bragg gratings (FBGs with different characteristics, and multiple sensor heads with cascade and/or parallel forms. The power-budget analysis and limitations of the measurement rates are discussed, and the measurement results of fiber-reinforced plastic (FRP coupon strain using the proposed FOS are given as an actual measurement. The proposed FOS has several benefits, including a self-referencing characteristic, the flexibility to determine FBGs, and a simple structure in terms of the number of devices and measuring procedure.

  17. Structural health monitoring of composite-based UAVs using simultaneous fiber optic interrogation by static Rayleigh-based distributed sensing and dynamic fiber Bragg grating point sensors

    Science.gov (United States)

    Tur, Moshe; Sovran, Ido; Bergman, Arik; Motil, Avi; Shapira, Osher; Ben-Simon, Uri; Kressel, Iddo

    2015-09-01

    Embedded fiber-optic strain sensing networks for airworthy assessment of operational Unmanned Aerial Vehicles (UAVs) are presented. Sensing is based on in-flight fiber Bragg grating technology, as well as on on-ground Rayleigh backscattering distributed strain sensing. While the in-flight instrumentation monitors loads, looking for excessive values, the Rayleigh-based technique is used for high spatial resolution strain distribution along the UAV wings, under prescribed loading. Consistency of measurements over time indicates structural integrity. Simultaneous strain measurements using both distributed Rayleigh and fiber Bragg gratings, on the same fiber, promises to combine high spatial resolution, though practically static measurements with dynamic, though discrete ones.

  18. Double-Ended Calibration of Fiber-Optic Raman Spectra Distributed Temperature Sensing Data

    Directory of Open Access Journals (Sweden)

    John Selker

    2012-04-01

    Full Text Available Over the past five years, Distributed Temperature Sensing (DTS along fiber optic cables using Raman backscattering has become an important tool in the environmental sciences. Many environmental applications of DTS demand very accurate temperature measurements, with typical RMSE < 0.1 K. The aim of this paper is to describe and clarify the advantages and disadvantages of double-ended calibration to achieve such accuracy under field conditions. By measuring backscatter from both ends of the fiber optic cable, one can redress the effects of differential attenuation, as caused by bends, splices, and connectors. The methodological principles behind the double-ended calibration are presented, together with a set of practical considerations for field deployment. The results from a field experiment are presented, which show that with double-ended calibration good accuracies can be attained in the field.

  19. Application of optical fiber sensing technique to fast breeder reactor plants

    International Nuclear Information System (INIS)

    Optical fiber thermometers have some characteristics such as non-induction for electromagnetic interference noises, capability of measuring continuous temperature distribution ranging to even some km along the fiber by differing from conventional electric spot-type sensors such as thermocouple, and so on, so it can be expected to largely contribute to safety and reliability from viewpoints of monitoring and maintenance of plants, by applying the characteristics to temperature measurements of apparatuses and pipings in a fast breeder reactor (FBR) plant. As temperature measuring technology using optical fibers is already practiced at fire detection of buildings, tunnels, and so on, because of increasing transmission loss based on effects of radiation when using at nuclear reactor plants, it is important to adequately compensate this increase. Here was introduced an R and D result to make practice on temperature and radiation measuring methods at radiation environment, by applying optical fiber sensing technique to the fast breeder test-reactor, 'Joyo' of a sodium cooling-type FBR of JNC. (G.K.)

  20. Study of sensing properties and contrastive analysis of metal coating optical fiber grating

    Science.gov (United States)

    Wang, Jing; Wang, Ning; Shi, Bin; Sui, Qingmei; Guan, Congsheng; Wei, Guangqing; Li, Shuhua

    2014-02-01

    Optical fiber grating (FBG) has been widely used in the measurement of parameters such as temperature and strain. However, FBG is too slim to broken, whose outside protective layer tends to shedding easily, and it is also hard to change the temperature and strain sensitivity. In order to overcome the above disadvantages and to further expand the application range of FBG, this paper improves the technology of fiber grating metal film plating process firstly. It adopts a compositive method including chemical plating and electroplating to gild FBG, copper FBG and galvanize FBG, which all get good metal coating. Then, the temperature and strain sensing properties of metalized FBG is studied in detail. Multiple metal coating FBGs were put in high-low temperature test-box together, and then the test-box worked continuously at the temperature range of 0°C?95°C. After several experiments, it concludes that metal plating enhances the temperature sensitivity of fiber grating, and the one with galvanization has the highest temperature sensitivity of 0.0235. At last, FBGs with various cladding were pasted on carbon fiber cantilever beam respectively and the pressure on the top of the cantilever increased gradually. The experimental results show that wavelength of fiber grating shift toward the long wavelength with the increase of the pressure, and the one with galvanization has the maximum strain sensitivity which has minimal impact on fiber properties.

  1. Design and Fabrication of Fiber-Optic Nanoprobes for Optical Sensing

    Directory of Open Access Journals (Sweden)

    Zhang Yan

    2011-01-01

    Full Text Available Abstract This paper describes the design and fabrication of fiber-optic nanoprobes developed for optical detection in single living cells. It is critical to fabricate probes with well-controlled nanoapertures for optimized spatial resolution and optical transmission. The detection sensitivity of fiber-optic nanoprobe depends mainly on the extremely small excitation volume that is determined by the aperture sizes and penetration depths. We investigate the angle dependence of the aperture in shadow evaporation of the metal coating onto the tip wall. It was found that nanoaperture diameters of approximately 50 nm can be achieved using a 25° tilt angle. On the other hand, the aperture size is sensitive to the subtle change of the metal evaporation angle and could be blocked by irregular metal grains. Through focused ion beam (FIB milling, optical nanoprobes with well-defined aperture size as small as 200 nm can be obtained. Finally, we illustrate the use of the nanoprobes by detecting a fluorescent species, benzo[a]pyrene tetrol (BPT, in single living cells. A quantitative estimation of the numbers of BPT molecules detected using fiber-optic nanoprobes for BPT solutions shows that the limit of detection was approximately 100 molecules.

  2. An Implantable Neural Sensing Microsystem with Fiber-Optic Data Transmission and Power Delivery

    Directory of Open Access Journals (Sweden)

    Yoon-Kyu Song

    2013-05-01

    Full Text Available We have developed a prototype cortical neural sensing microsystem for brain implantable neuroengineering applications. Its key feature is that both the transmission of broadband, multichannel neural data and power required for the embedded microelectronics are provided by optical fiber access. The fiber-optic system is aimed at enabling neural recording from rodents and primates by converting cortical signals to a digital stream of infrared light pulses. In the full microsystem whose performance is summarized in this paper, an analog-to-digital converter and a low power digital controller IC have been integrated with a low threshold, semiconductor laser to extract the digitized neural signals optically from the implantable unit. The microsystem also acquires electrical power and synchronization clocks via optical fibers from an external laser by using a highly efficient photovoltaic cell on board. The implantable unit employs a flexible polymer substrate to integrate analog and digital microelectronics and on-chip optoelectronic components, while adapting to the anatomical and physiological constraints of the environment. A low power analog CMOS chip, which includes preamplifier and multiplexing circuitry, is directly flip-chip bonded to the microelectrode array to form the cortical neurosensor device.

  3. Temperature sensing in high voltage transmission lines using fiber Bragg grating and free-space-optics

    Science.gov (United States)

    Floridia, Claudio; Rosolem, Joao B.; Leonardi, Ariovaldo A.; Hortencio, Claudio A.; Fonseca, Romeu F.; Moreira, Rodrigo O. C.; Souza, Giovani C. L.; Melo, Altair L.; Nascimento, Carlos A. M.

    2013-05-01

    In this work we proposed the use of free-space-optics (FSO) to transmit and receive the optical signals from optical fiber placed in ground potential to the FBG fiber optics at high voltage potential, using a pair of optical collimators. The technique evaluation was performed in a prototype for the study of sensitivity to optical alignment and in an external environment using emulated sensing systems for both bus bar and overhead transmission line with real isolator chain. It has been shown that the FSO system allows collimators operate at distances of 500 mm to 2.000 mm. This range of distances is similar to the length of insulator's chain up to 230 kV. It was also shown that the proposed system can be used in real external environment for bus bar temperature monitoring in substations, where, even if the time out of the system is of 45%, with major interruption time of almost 15 hours, the majority of the interruption time was less than 18 minutes long. On the other hand, system has to be improved in order to be used in overhead transmission line. As tested for a real isolator chain the system shown a time out of 80.3%, with significant number of events of interruption acquisition time greater than 150 minutes. It is believed that for overhead power lines, system must be installed in rigid surge arresters or in a line post where it is expected to have similar results as in substation bus bars monitoring.

  4. Fiber optic detector

    Energy Technology Data Exchange (ETDEWEB)

    Partin, J.K.; Ward, T.E.; Grey, A.E.

    1990-12-31

    This invention is comprised of a portable fiber optic detector that senses the presence of specific target chemicals by exchanging the target chemical for a fluorescently-tagged antigen that is bound to an antibody which is in turn attached to an optical fiber. Replacing the fluorescently-tagged antigen reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.

  5. Sensing of corrosion on aluminum surfaces by use of metallic optical fiber.

    Science.gov (United States)

    Dong, Saying; Liao, Yanbiao; Tian, Qian

    2005-10-20

    We present a new method for monitoring aluminum corrosion by determining the kind of light output that is as corrosion occurs. We prepared some metallized multimode optical fibers by physical vacuum deposition of aluminum to monitor metal corrosion. The sensing area was 1-2 cm in length and had an uncladded part. We used scanning-electron microscopy (SEM) to observe the microappearance of the aluminum before and after corrosion by sodium hydroxide or hydrochloric acid. The film's thickness was also measured by SEM. The factors that affect the rate of corrosion were also investigated. PMID:16252643

  6. Sensing of corrosion on aluminum surfaces by use of metallic optical fiber

    Science.gov (United States)

    Dong, Saying; Liao, Yanbiao; Tian, Qian

    2005-10-01

    We present a new method for monitoring aluminum corrosion by determining the kind of light output that is as corrosion occurs. We prepared some metallized multimode optical fibers by physical vacuum deposition of aluminum to monitor metal corrosion. The sensing area was 1 2 cm in length and had an uncladded part. We used scanning-electron microscopy (SEM) to observe the microappearance of the aluminum before and after corrosion by sodium hydroxide or hydrochloric acid. The film's thickness was also measured by SEM. The factors that affect the rate of corrosion were also investigated.

  7. Multipoint vibration sensing using fiber Bragg gratings and optical frequency domain reflectometry.

    Science.gov (United States)

    Wada, Atsushi; Tanaka, Satoshi; Takahashi, Nobuaki

    2015-07-01

    We present multipoint vibration sensing using fiber Bragg gratings and optical frequency domain refrectometry (OFDR). In OFDR based method, the maximum number of arrayed sensor can be few thousands and the measurement time is determined by wavelength scanning rate of a light source. In our sensor system, a laser diode is used as a wavelength scanning light source. Lasing wavelength of a laser diode can be modulated by changing its injection current. The injection current can be precisely modulated at high frequency up to 100 kHz using a laser-diode controller and wavelength scanning can be then easily achieved with a laser diode.

  8. Optical sensing elements for nitrogen dioxide (NO.sub.2) gas detection, a sol-gel method for making the sensing elements and fiber optic sensors incorporating nitrogen dioxide gas optical sensing elements

    Science.gov (United States)

    Mechery, Shelly John (Mississippi State, MS); Singh, Jagdish P. (Starkville, MS)

    2007-07-03

    A sensing element, a method of making a sensing element, and a fiber optic sensor incorporating the sensing element are described. The sensor can be used for the quantitative detection of NO.sub.2 in a mixture of gases. The sensing element can be made by incorporating a diazotizing reagent which reacts with nitrous ions to produce a diazo compound and a coupling reagent which couples with the diazo compound to produce an azo dye into a sol and allowing the sol to form an optically transparent gel. The sensing element changes color in the presence of NO.sub.2 gas. The temporal response of the absorption spectrum at various NO.sub.2 concentrations has also been recorded and analyzed. Sensors having different design configurations are described. The sensing element can detect NO.sub.2 gas at levels of parts per billion.

  9. Optical Fiber Networks for Remote Fiber Optic Sensors

    OpenAIRE

    Montserrat Fernandez-Vallejo; Manuel Lopez-Amo

    2012-01-01

    This paper presents an overview of optical fiber sensor networks for remote sensing. Firstly, the state of the art of remote fiber sensor systems has been considered. We have summarized the great evolution of these systems in recent years; this progress confirms that fiber-optic remote sensing is a promising technology with a wide field of practical applications. Afterwards, the most representative remote fiber-optic sensor systems are briefly explained, discussing their schemes, challenges, ...

  10. Fiber optic sensing system for temperature and gas monitoring in coal waste pile combustion environments

    Science.gov (United States)

    Viveiros, D.; Ribeiro, J.; Ferreira, J.; Lopez-Albada, A.; Pinto, A. M. R.; Perez-Herrera, R. A.; Diaz, S.; Lopez-Gil, A.; Dominguez-Lopez, A.; Esteban, O.; Martin-Lopez, S.; Auguste, J.-L.; Jamier, R.; Rougier, S.; Silva, S. O.; Frazão, O.; Santos, J. L.; Flores, D.; Roy, P.; Gonzalez-Herraez, M.; Lopez-Amo, M.; Baptista, J. M.

    2015-09-01

    It is presented an optical fiber sensing system projected to operate in the demanding conditions associated with coal waste piles in combustion. Distributed temperature measurement and spot gas sensing are requirements for such a system. A field prototype has been installed and is continuously gathering data, which will input a geological model of the coal waste piles in combustion aiming to understand their dynamics and evolution. Results are presented on distributed temperature and ammonia measurement, being noticed any significant methane emission in the short time period considered. Carbon dioxide is also a targeted gas for measurement, with validated results available soon. The assessment of this technology as an effective and reliable tool to address the problem of monitoring coal waste piles in combustion opens the possibility of its widespread application in view of the worldwide presence of coal related fires.

  11. Nanocrystalline diamond microelectrode on fused silica optical fibers for electrochemical and optical sensing

    Science.gov (United States)

    Bogdanowicz, Robert; Sobaszek, Micha?; Ficek, Mateusz; Gnyba, Marcin; Ryl, Jacek; Siuzdak, Katarzyna; ?mietana, Mateusz

    2015-07-01

    Fabrication process of thin boron-doped nanocrystalline diamond (B-NCD) microelectrode on fused silica single mode optical fiber has been investigated. The B-NCD films were deposited on the fibers using Microwave Plasma Assisted Chemical Vapor Deposition (MW PA CVD) at glass substrate temperature of 475 ºC. We have obtained homogenous, continuous and polycrystalline surface morphology with the mean grain size in the range of 100-250 nm and high sp3 content in B-NCD films. The films deposited on glass reference samples exhibit high refractive index (n?2.05 at ?=550 nm) and low extinction coefficient. Furthermore, cyclic voltammograms (CV) were recorded to determine the electrochemical window and reaction reversibility at the B-NCD fibre-based electrode. Cyclic voltammetry (CV) measurements in aqueous media consisting of 5mM K3[Fe(CN)6] in 0.1M Na2SO4 demonstrated a width of the electrochemical window up to 2.5 V and relatively fast kinetics expressed by a redox peak splitting below 500 mV. Moreover, thanks to high-n B-NCD overlay, the coated fibers can be also used for enhancing sensitivity of long-period gratings (LPGs) induced in the fibers. The LPG is capable for measuring variations in refractive index of surrounding liquid by tracing shift in resonance appearing in transmitted spectrum. Possible combined CV and LPG-based measurements are discussed in this work.

  12. Sensing interrogation technique for fiber-optic interferometer type of sensors based on a single-passband RF filter.

    Science.gov (United States)

    Chen, Hao; Zhang, Shiwei; Fu, Hongyan; Zhou, Bin; Chen, Nan

    2016-02-01

    In this paper, a sensing interrogation system for fiber-optic interferometer type of sensors by using a single-passband radio-frequency (RF) filter has been proposed and experimentally demonstrated. The fiber-optic interferometer based sensors can give continuous optical sampling, and along with dispersive medium a single-passband RF frequency response can be achieved. The sensing parameter variation on the fiber-optic interferometer type of sensors will affect their free spectrum range, and thus the peak frequency of the RF filter. By tracking the central frequency of the passband the sensing parameter can be demodulated. As a demonstration, in our experiment a fiber Mach-Zehnder interferometer (FMZI) based temperature sensor has been interrogated. By tracking the peak frequency of the passband the temperature variation can be monitored. In our experiment, the sensing responsivity of 10.5 MHz/°C, 20.0 MHz/°C and 41.2 MHz/°C, when the lengths of sensing fiber are 1 m, 2 m and 4 m have been achieved. PMID:26906846

  13. Changes in speckle patterns induced by load application onto an optical fiber and its possible application for sensing purpose

    Science.gov (United States)

    Hasegawa, Makoto; Okumura, Jyun-ya; Hyuga, Akio

    2015-08-01

    Speckle patterns to be observed in an output light spot from an optical fiber are known to be changed due to external disturbances applied onto the optical fiber. In order to investigate possibilities of utilizing such changes in speckle patterns for sensing application, a certain load was applied onto a jacket-covered communication-grade multi-mode glass optical fiber through which laser beams emitted from a laser diode were propagating, and observed changes in speckle patterns in the output light spot from the optical fiber were investigated both as image data via a CCD camera and as an output voltage from a photovoltaic panel irradiated with the output light spot. The load was applied via a load application mechanism in which several ridges were provided onto opposite flat plates and a certain number of weights were placed there so that corrugated bending of the optical fiber was intentionally induced via load application due to the ridges. The obtained results showed that the number of speckles in the observed pattern in the output light spot as well as the output voltage from the photovoltaic panel irradiated with the output light spot showed decreases upon load application with relatively satisfactory repeatability. When the load was reduced, i.e., the weights were removed, the number of speckles then showed recovery. These results indicate there is a certain possibility of utilizing changes in speckle patterns for sensing of load application onto the optical fiber.

  14. In-situ strain sensing with fiber optic sensors embedded into stainless steel 316

    Science.gov (United States)

    Havermann, Dirk; Mathew, Jinesh; Macpherson, William N.; Maier, Robert R. J.; Hand, Duncan P.

    2015-04-01

    Fiber Bragg Grating (FBG) sensors are embedded into Stainless Steel (SS) 316 components using bespoke Selective Laser Melting (SLM) technology. SS 316 material is added on substrates by SLM, incorporating U-shaped grooves with dimensions suitable to hold nickel coated optical fibers. Coated optical fibers containing fiber Bragg gratings for strain monitoring are placed in the groove. Melting subsequent powder layer on top of the fiber completes the embedding. Strain levels exceeding 3 m? are applied to specimens and are measured by embedded fiber optic sensors. Elastic deformation of the steel component is reliably measured by the Bragg grating from within the component with high accuracy. During plastic deformation of the steel the optical fiber is slipping due to poor adhesive bonding between fused silica and metal surround.

  15. Spatio-temporal noise and drift in fiber optic distributed temperature sensing

    International Nuclear Information System (INIS)

    Distributed temperature sensing (DTS) allows for simultaneous measurement at many remote locations along an optical fiber probe and is a valuable tool in a broad range of applications, such as downhole oil production, dike structural monitoring or fire protection. The specific requirements on spatial, temporal and temperature resolution and on absolute measurement uncertainty vary with the applications. We investigate the spatio-temporal noise and drift properties of two exemplary Raman backscatter DTS systems and discuss the effect of spatial and temporal data averaging. An Allan deviation analysis provides insight into the optimal degree of averaging for a given distance range along the fiber probe. A temperature calibration procedure is employed to retrieve the temperature sensitivity of the DTS system and to compensate for the systematic spatial slope of recorded DTS temperature measurement traces. In response to small temperature steps of a thermally homogeneous and stable water bath environment, we observe a temperature resolution of approximately 0.05 °C at a chosen 1000 m sampling distance along the fiber probe

  16. Fiber bragg gratings in polymer optical fibers

    OpenAIRE

    Harbach, Nico Gérard

    2008-01-01

    Polymer optical fibers (POF) have received increased attention in recent years in the fields of data communication and sensing applications. The lower cost and higher flexibility are the main advantages of POF compared to silica fibers and make them interesting candidates for Fiber Bragg grating (FBG) sensor applications. FBG are convenient measurement devices for strain and temperature measurements, as they can be multiplexed within one fiber yielding a sensor array and the fiber can be embe...

  17. A tactile sensing element based on a hetero-core optical fiber for force measurement and texture detection

    Science.gov (United States)

    Yamazaki, Hiroshi; Koyama, Yuya; Watanabe, Kazuhiro

    2014-05-01

    Tactile sensing technology can measure a given property of an object through physical contact between a sensing element and the object. Various tactile sensing techniques have been developed for several applications such as intelligent robots, tactile interface, medical support and nursing care support. A desirable tactile sensing element for supporting human daily life can be embedded in the soft material with high sensitivity and accuracy in order to prevent from damaging to human or object physically. This report describes a new tactile sensing element. Hetero-core optical fibers have high sensitivity of macro-bending at local sensor portion and temperature independency, including advantages of optical fiber itself; thin size, light weight, flexible transmission line, and immunity to electro-magnetic interference. The proposed tactile sensing element could detect textures of touched objects through the optical loss caused by the force applied to the sensing element. The characteristics of the sensing element have been evaluated, in which the sensing element has the monotonic and non-linear sensitivity against the normal force ranged from 0 to 5 N with lower accuracy than 0.25 dB. Additionally, texture detection have been successfully demonstrated in which small surface figures of 0.1 mm in height were detected with spatial resolution of 0.4 mm.

  18. Fiber optic distributed temperature sensing for the determination of the nocturnal atmospheric boundary layer height

    Directory of Open Access Journals (Sweden)

    C. A. Keller

    2011-02-01

    Full Text Available A new method for measuring air temperature profiles in the atmospheric boundary layer at high spatial and temporal resolution is presented. The measurements are based on Raman scattering distributed temperature sensing (DTS with a fiber optic cable attached to a tethered balloon. These data were used to estimate the height of the stable nocturnal boundary layer. The experiment was successfully deployed during a two-day campaign in September 2009, providing evidence that DTS is well suited for this atmospheric application. Observed stable temperature profiles exhibit an exponential shape confirming similarity concepts of the temperature inversion close to the surface. The atmospheric mixing height (MH was estimated to vary between 5 m and 50 m as a result of the nocturnal boundary layer evolution. This value is in good agreement with the MH derived from concurrent Radon-222 (222Rn measurements and in previous studies.

  19. Fiber optic distributed temperature sensing for the determination of the nocturnal atmospheric boundary layer height

    Directory of Open Access Journals (Sweden)

    C. A. Keller

    2010-06-01

    Full Text Available A new method for measuring air temperature profiles in the atmospheric boundary layer at high spatial and temporal resolution is presented. The measurements are based on Raman scattering distributed temperature sensing (DTS with a fiber optic cable attached to a tethered balloon. These data were used to estimate the height of the stable nocturnal boundary layer. The experiment was successfully deployed during a two-day campaign in September 2009, providing evidence that DTS is well suited for this atmospheric application. Observed stable temperature profiles exhibit an exponential shape confirming similarity concepts of the temperature inversion close to the surface. The atmospheric mixing height (MH was estimated to vary between 5 m and 50 m as a result of the nocturnal boundary layer evolution. This value is in good agreement to the MH derived from concurrent Radon-222 (222Rn measurements and in previous studies.

  20. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Gregory L. Baker; Ruby N. Ghosh; D. J. Osborn; Po Zhang

    2006-09-30

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications has been developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. We report on a fiber optic technique for detection of gas phase oxygen up to 100 C based on the {sup 3}O{sub 2} quenching of the luminescence from molybdenum chloride clusters, K{sub 2}Mo{sub 6}Cl{sub 14}. The inorganic sensing film is a composite of sol-gel particles embedded in a thin, oxygen permeable sol-gel binder. The particles are comprised of thermally stable, luminescent K{sub 2}Mo{sub 6}Cl{sub 14} clusters dispersed in a fully equilibrated sol-gel matrix. From 40 to 100 C, the fiber sensor switches {approx}6x in intensity in response to alternating pulses of <0.001% O2 and 21% O{sub 2} between two well defined levels with a response time of 10 s. The sensor signal is a few nW for an input pump power of 250 {micro}W. The normalized sensor signal is linear with molar oxygen concentration and fits the theoretical Stern-Volmer relationship. Although the sensitivity decreases with temperature, sensitivity at 100 C is 160 [O{sub 2}]{sup -1}. These parameters are well suited for in-situ, real-time monitoring of oxygen for industrial process control applications.

  1. A Finite Element Analysis of Fiber Optic Acoustic Sensing Mandrel for Acoustic pressure with Increased Sensitivity

    Directory of Open Access Journals (Sweden)

    Prashil M. Junghare

    2013-09-01

    Full Text Available - This paper investigates the influence of material properties on the performance of an optical fiber wound mandrel composite fiber optic interferometer mandrel by using the ANSYS Cad tool, The acoustic sensitivity of an optical fiber considered analytically, High sensitivity obtained with low young modulus, very thick polymer coatings. The thick coating realized by embedding optical fiber in polyurethane. A flexible composite fiber-optic interferometric acoustic sensor has been developed by wrapping single mode fiber in a winding manner and then embedding a fiber in a thin polyurethane layer. The acoustic sensitivity has to be found more in a frequency range of (2.5-5.0 KHz. In this paper we studied the structural and material properties of a mandrel sensor with foaming layer in such way to get the optimal performance. The sensor was found to be compatible with water. Also the performance of optical fiber is analytically verified using the MATLAB software. In this paper the design was simulated in ANSYS Cad Tool, to verify the sensitivity of the Optical Mach-Zehnder Interferometric Sensor for increased sensitivity. The main objective and focus of the above work is concentrated on choosing the optimal foaming layer material by varying the Young Modulus E to choose the perfect foaming material for implementing in the design of mandrel.

  2. A Fourier domain mode-locked fiber laser based on dual-pump fiber optical parametric amplification and its application for a sensing system

    International Nuclear Information System (INIS)

    A Fourier domain mode-locked (FDML) fiber laser based on dual-pump fiber optical parametric amplification (FOPA) is proposed and demonstrated. The output spectrum of the proposed FDML fiber laser covers a sweeping wavelength range from 1540.8 to 1559.8 nm with a sweeping frequency of 31.688 kHz. A comparison of two FDML fiber lasers which are based on dual-pump FOPA and one-pump FOPA is also presented. A novel sensing system based on the FDML laser and a fiber Bragg grating, by which the sensing signal can be measured in the time domain instead of the frequency domain, is also demonstrated. (paper)

  3. Research on the feature extraction and pattern recognition of the distributed optical fiber sensing signal

    Science.gov (United States)

    Wang, Bingjie; Sun, Qi; Pi, Shaohua; Wu, Hongyan

    2014-09-01

    In this paper, feature extraction and pattern recognition of the distributed optical fiber sensing signal have been studied. We adopt Mel-Frequency Cepstral Coefficient (MFCC) feature extraction, wavelet packet energy feature extraction and wavelet packet Shannon entropy feature extraction methods to obtain sensing signals (such as speak, wind, thunder and rain signals, etc.) characteristic vectors respectively, and then perform pattern recognition via RBF neural network. Performances of these three feature extraction methods are compared according to the results. We choose MFCC characteristic vector to be 12-dimensional. For wavelet packet feature extraction, signals are decomposed into six layers by Daubechies wavelet packet transform, in which 64 frequency constituents as characteristic vector are respectively extracted. In the process of pattern recognition, the value of diffusion coefficient is introduced to increase the recognition accuracy, while keeping the samples for testing algorithm the same. Recognition results show that wavelet packet Shannon entropy feature extraction method yields the best recognition accuracy which is up to 97%; the performance of 12-dimensional MFCC feature extraction method is less satisfactory; the performance of wavelet packet energy feature extraction method is the worst.

  4. Cardiac-induced localized thoracic motion detected by a fiber optic sensing scheme

    Science.gov (United States)

    Allsop, Thomas; Lloyd, Glynn; Bhamber, Ranjeet S.; Hadzievski, Ljupco; Halliday, Michael; Webb, David J.; Bennion, Ian

    2014-11-01

    The cardiovascular health of the human population is a major concern for medical clinicians, with cardiovascular diseases responsible for 48% of all deaths worldwide, according to the World Health Organization. The development of new diagnostic tools that are practicable and economical to scrutinize the cardiovascular health of humans is a major driver for clinicians. We offer a new technique to obtain seismocardiographic signals up to 54 Hz covering both ballistocardiography (below 20 Hz) and audible heart sounds (20 Hz upward), using a system based on curvature sensors formed from fiber optic long period gratings. This system can visualize the real-time three-dimensional (3-D) mechanical motion of the heart by using the data from the sensing array in conjunction with a bespoke 3-D shape reconstruction algorithm. Visualization is demonstrated by adhering three to four sensors on the outside of the thorax and in close proximity to the apex of the heart; the sensing scheme revealed a complex motion of the heart wall next to the apex region of the heart. The detection scheme is low-cost, portable, easily operated and has the potential for ambulatory applications.

  5. SPR based fiber optic sensor for refractive index sensing with enhanced detection accuracy and figure of merit in visible region

    Science.gov (United States)

    Mishra, Akhilesh K.; Mishra, Satyendra K.; Gupta, Banshi D.

    2015-06-01

    We, theoretically, propose a surface plasmon resonance (SPR) based indium tin oxide (ITO)-silver (Ag) coated fiber optic sensing probe for refractive index sensing in visible regime of the electromagnetic spectrum. A comparative study of ITO+Ag coated probe with Ag coated probe and with ITO coated probe using their respective optimized film thicknesses is carried out. We show that the proposed probe is endowed with the better sensitivity characteristic of ITO and better detection accuracy (DA) characteristic of Ag, and can sense change in refractive index with enhanced DA and figure of merit (FOM) in the visible region.

  6. Interrogation technique for a fiber Bragg grating sensing array based on a Sagnac interferometer and an acousto-optic modulator.

    Science.gov (United States)

    Zhou, Bin; Guan, Zuguang; Yan, Chunsheng; He, Sailing

    2008-11-01

    We propose and experimentally demonstrate a novel real-time interrogation technique for a fiber Bragg grating (FBG) sensing system that is based on a frequency-shifted asymmetric Sagnac interferometer. FBG sensors are connected to the Sagnac loop by an optical coupler, and an acousto-optic modulator (AOM) is asymmetrically placed in the Sagnac loop. By linearly sweeping the driving frequency of the AOM, the environmental variation around each FBG sensor can be determined by measuring the spectrum of the interference signals of the two counterpropagating light beams reflected by the corresponding FBG. The system has the advantages of low cost and real-time sensing. PMID:18978895

  7. Advanced Modular, Multi-Channel, High Speed Fiber Optic Sensing System for Acoustic Emissions Monitoring Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Intelligent Fiber Optic Systems Corporation (IFOS) proposes to prove the feasibility of innovations based on ultra-light-weight, ultra-high-speed, multi-channel,...

  8. Fiber-Optic Shape Sensing for Intelligent Solar Sail Deployment Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Luna Innovations proposes to develop a distributed fiber-optic shape sensor to provide a control system for the deployment of ultra-lightweight inflatable support...

  9. Standardization in fiber-optic sensing for structural safety: activities in the ISHMII and IEC

    Science.gov (United States)

    Habel, Wolfgang R.; Krebber, K.; Daum, W.

    2015-03-01

    Fiber-optic sensors are increasingly established in the sensor market. Their advantages have unquestionably been verified by numerous demonstrations to enhance the operational performance of aged structures or to monitor the structural behavior of safety-relevant structures or their components. However, there are some barriers in use due to a lack of extensive standardization of fiber-optic sensors. This leads very often to restraints in the user's community. The paper shows the status in international standardization of fiber-optic sensors as well as current activities in leading institutions such as IEC and ISHMII and others with the purpose of providing relevant standards for a broader use of selected fiber-optic sensor technologies.

  10. Cryogenic Liquid Level-Sensing using Fiber-Optic Strain Sensor (FOSS) Technology Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Armstrong innovators have developed a highly accurate method for measuring liquid levels using optical fibers. Unlike liquid level gauges that rely on discrete...

  11. Reflectance response of tapered optical fiber coated with graphene oxide nanostructured thin film for aqueous ethanol sensing

    Science.gov (United States)

    Shabaneh, A. A.; Girei, S. H.; Arasu, P. T.; Rahman, W. B. W. A.; Bakar, A. A. A.; Sadek, A. Z.; Lim, H. N.; Huang, N. M.; Yaacob, M. H.

    2014-11-01

    In this work, optical sensing performance of tapered multimode fiber tip coated with graphene oxide (GO) nanostructured thin film towards aqueous ethanol with different concentrations is investigated. The tapering process of the optical fiber is done by a glass processing machine. The multimode optical fiber tip is dip-coated with GO and annealed at 70 °C to enhance the binding of the nanomaterials to the silica fiber. FESEM, Raman microscopy and XRD analyses are performed to micro-characterize the GO thin films. The morphology of the GO is observed to be in sheets forms. The reflectance response of the GO coated fiber tip is compared with the uncoated tip. The measurements are taken using a spectrophotometer in the optical wavelength range of 550-720 nm. The reflectance response of the GO coated fiber tip reduced proportionally, upon exposure to ethanol with concentration range of 5-80%. The dynamic response of the developed sensor showed strong reversibility and repeatability when it is exposed to ethanol with concentrations of 5%, 20% and 40% in distilled water. At room temperature, the sensor shows fast response and recovery as low as 19 and 25 s, respectively.

  12. Combined imaging and chemical sensing using a single optical imaging fiber.

    Science.gov (United States)

    Bronk, K S; Michael, K L; Pantano, P; Walt, D R

    1995-09-01

    Despite many innovations and developments in the field of fiber-optic chemical sensors, optical fibers have not been employed to both view a sample and concurrently detect an analyte of interest. While chemical sensors employing a single optical fiber or a noncoherent fiberoptic bundle have been applied to a wide variety of analytical determinations, they cannot be used for imaging. Similarly, coherent imaging fibers have been employed only for their originally intended purpose, image transmission. We herein report a new technique for viewing a sample and measuring surface chemical concentrations that employs a coherent imaging fiber. The method is based on the deposition of a thin, analyte-sensitive polymer layer on the distal surface of a 350-microns-diameter imaging fiber. We present results from a pH sensor array and an acetylcholine biosensor array, each of which contains approximately 6000 optical sensors. The acetylcholine biosensor has a detection limit of 35 microM and a fast (fibers can display visual information of a remote sample with 4-microns spatial resolution, allowing for alternating acquisition of both chemical analysis and visual histology. PMID:8779411

  13. Fiber Optic Sensors and Sensor Networks Using a Time-domain Sensing Scheme

    OpenAIRE

    Chuji Wang; Malik Kaya; Peeyush Sahay; Haifa Alali; Robert Reese

    2013-01-01

    Fiber loop ringdown (FLRD) has demonstrated to be capable of sensing various quantities, such as chemical species, pressure, refractive index, strain, temperature, etc.; and it has high potential for the development of a sensor network. In the present work, we describe design and development of three different types of FLRD sensors for water, cracks, and temperature sensing in concrete structures. All of the three aforementioned sensors were indigenously developed very recently in our labora...

  14. Measurement and analysis of water vapor inside optical components for optical fiber H2O sensing system.

    Science.gov (United States)

    Wang, Qiang; Chang, Jun; Song, Fujun; Wang, Fupeng; Zhu, Cunguang; Liu, Zhi; Zhang, Sasa; Liu, Xiangzhi

    2013-09-10

    Water vapor existing inside internal end-face gaps of optical components of an optical fiber H2O sensing system makes it possible to influence the measurement accuracy and stability. The influence principle has been briefly analyzed based on the structure of three main optical components: a distributed feedback laser diode (DFB-LD), a collimator, and a photoelectric diode (PD). With application of a differential technique, the influence of water vapor inside the DFB-LD can be removed. With reasonable recombination of the collimator and the PD in a dual-beam detection system, the influence of water vapor inside the collimator and the PD's end-face gaps has been suppressed from more than 1.57×10(-3) to as low as -2.175×10(-5) in absorbance. After H2O isolation processing water vapor inside the end-face gaps of the DFB-LD, the collimator, and the PD can be utilized as a reference to design a simple but feasible H2O sensor. As a result, good linearity with an R2 of 0.9964 has been realized in a concentration range of 39-2110 ppm during an application test, and a long-term test of the designed H2O sensor against the S8000 with a difference of 10 ppm has been achieved. PMID:24085118

  15. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    International Nuclear Information System (INIS)

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the 3O2 quenching of the red emission from hexanuclear molybdenum chloride clusters. High temperature measurements of the emission of clusters in sol gel films show that the luminescence intensity from the films follow a 1/T relationship from room temperature to 150 C, and then declines at a slower rate at higher temperatures. The large number of photons available at 230 C is consistent with simple low cost optics for fiber optic probes based on the emission from clusters in sol gel films

  16. Characterizing Groundwater Flowpaths with Fiber-Optic Distributed Temperature Sensing and Stable Isotopes

    Science.gov (United States)

    Peri, L.; Gryczkowski, L.; Zheng, Y.; Liu, J.; Wang, S.; Wu, B.; Yao, Y.; Huang, X.; Wei, H.; Liu, C.; Hu, Y.; Wu, X.; Yu, L.

    2012-12-01

    The Heihe River basin of Northern China experiences high demand for scarce water. The upper watershed consists of alpine mountains and glaciers while the lower watershed is the arid Gobi Desert. The middle basin is important for agriculture production and has an extensive network of irrigation canals that reduce flow in the Heihe River. The lower watershed therefore receives reduced flow which is impacting fragile desert environments. Sustainably managing water resources in the basin while allowing for continued agriculture requires enhanced understanding of watershed function and behavior. A hydrologic model is being developed of the middle basin to help address these issues. The identification of groundwater and surface water interactions is an important component for an accurate model. Fiber-optic Distributed Temperature Sensing (DTS) is being used in 2012 to help identify these processes. Stable isotope differences (deuterium and O-18) are also being used in areas of potential groundwater discharge identified by DTS to improve understanding of flowpaths within the watershed. This interactive study promotes future sustainable water resource management to restore desert ecosystems.

  17. A surface plasmon resonance probe without optical fibers as a portable sensing device

    International Nuclear Information System (INIS)

    A surface plasmon resonance (SPR) sensor integrating a small sensor probe, a laser emission diode, a photo detector, and a polarizer was developed as a portable sensing device. The sensor probe was made with a glass cylinder, 50 mm long and 1.5 mm in diameter, that was connected directly to a beam splitter without optical fibers. The SPR spectrum obtained with this probe system showed a 10% reflectivity minimum at 690 nm. Shifts of the SPR spectrum induced by refractive index (RI) changes in the sample were measured by detecting the reflection light intensity at 670 nm. When the sensitivity was compared using a BIAcoreTM SPR instrument, the lowest sensor response of 1 mV observed with the SPR probe system coincided with 1.4 x 10-6 of the RI changes. The RI resolution of the SPR probe was estimated with experimentally evaluated noise on the signal, and, consequently, it was concluded that the RI resolution was 1.2 x 10-5. Moreover, immunoreaction was demonstrated with adsorbed bovine serum albumin (BSA) and anti-BSA antibody as an analyte. As a result, 50 ng mL-1 of the lower detection limit was estimated

  18. Sapphire ball lensed fiber probe for common-path optical coherence tomography in ocular imaging and sensing

    OpenAIRE

    Zhao, Mingtao; Yong HUANG; Kang, Jin U

    2013-01-01

    We describe a novel common-path optical coherence tomography (CP-OCT) fiber probe design using a sapphire ball lens for cross-sectional imaging and sensing in retina vitrectomy surgery. Single mode Gaussian beam (TEM00) simulation was used to optimize lateral resolution and working distance (WD) of the common-path probe. A theoretical sensitivity model for CP-OCT was prosed to assess its optimal performance based an unbalanced photodetector configuration. Two probe designs with working distan...

  19. Sub-cm Resolution Distributed Fiber Optic Hydrogen Sensing with Nano-Engineered TiO2

    CERN Document Server

    Poole, Zsolt; Yan, Aidong; Lin, Yuankun; Chen, Kevin

    2015-01-01

    The 3D nano-structuring on the 2) to be reduced and matched with the cladding of optical fiber(n~1.46) for low-loss integration. A high temperature capable hydrogen sensor composed of D-shaped optical fiber with palladium nanoparticles infused nanoporous (~5nm) TiO2 film is demonstrated. The behavior of the developed sensor was characterized by examining the wavelength of an incorporated Fiber Bragg Grating and by observing the transmission losses at temperatures up to 700C. In addition, with frequency domain reflectometry the distributed sensing potential of the developed sensor for hydrogen concentrations of up to 10% is examined. The results show the possibility of detecting chemical gradients with sub-cm resolution at very high temperatures(>500C).

  20. Optical fiber Fabry-Perot interferometer with pH sensitive hydrogel film for hazardous gases sensing

    Science.gov (United States)

    Zheng, Yangzi; Chen, Li Han; Chan, Chi Chiu; Dong, Xinyong; Yang, Jingyi; Tou, Zhi Qiang; So, Ping Lam

    2015-09-01

    An optical fiber Fabry-Perot interferometer (FPI) coated with polyvinyl alcohol/poly-acrylic acid (PVA/PAA) hydrogel film for toxic gases measurement has been developed. Splicing a short section of hollow core fiber between two single mode fibers forms the FPI. Dip-coated pH-sensitive PVA/PAA hydrogel film on the fiber end performs as a receptor for binding of volatile acids or ammonia, which makes the sensing film swelling or shrinking and results in the dip wavelength shift of the FPI. By demodulating the evolution of reflection spectrum for various concentrations of volatile acids, a sensitivity of 20.8 nm/ppm is achieved with uniform linearity.

  1. Modal-interference-based temperature sensing using plastic optical fibers: markedly enhanced sensitivity near glass-transition temperature

    Science.gov (United States)

    Numata, Goki; Hayashi, Neisei; Tabaru, Marie; Mizuno, Yosuke; Nakamura, Kentaro

    2015-07-01

    We developed strain and temperature sensors based on multimode interference in perfluorinated graded-index (GI) plastic optical fibers, and investigate their sensing performance at 1300 nm. At room temperature, we achieve ultra-high sensitivities of strain and temperature of -112 pm/?? and +49.8 nm/°C/m, the absolute value of which are approximately 7.2 and over 1800 times as large as those in silica GI multimode fibers, respectively. We also find that the temperature sensitivity is drastically enhanced with increasing temperature toward ~80 °C, where phase transition of core polymer partially occurs.

  2. Optical Fiber Sensing of SF6 Degradation in High-Voltage Switchgear

    Science.gov (United States)

    Irawan, R.; Scelsi, G. B.; Woolsey, G. A.

    Sulphur hexafluoride (SF6) is used as an insulator in high-voltage systems. An electrical breakdown dissociates (SF6). Therefore, the insulating efficiency is degraded. If the (SF6) is not renewed, failure of the system can occur. A monitoring device for (SF6) loss is required, and an optical fiber sensor for continuous monitoring of (SF6) degradation in high-voltage switchgear has been developed. Dissociation products of the (SF6) discharge include HF and atomic F, both of which react readily with silica. This reactivity is utilized in our sensor, where etching of a glass fiber surface modifies the transmission characteristics of the fiber.

  3. Body-monitoring and health supervision by means of optical fiber-based sensing systems in medical textiles.

    Science.gov (United States)

    Quandt, Brit M; Scherer, Lukas J; Boesel, Luciano F; Wolf, Martin; Bona, Gian-Luca; Rossi, René M

    2015-02-18

    Long-term monitoring with optical fibers has moved into the focus of attention due to the applicability for medical measurements. Within this Review, setups of flexible, unobtrusive body-monitoring systems based on optical fibers and the respective measured vital parameters are in focus. Optical principles are discussed as well as the interaction of light with tissue. Optical fiber-based sensors that are already used in first trials are primarily selected for the section on possible applications. These medical textiles include the supervision of respiration, cardiac output, blood pressure, blood flow and its saturation with hemoglobin as well as oxygen, pressure, shear stress, mobility, gait, temperature, and electrolyte balance. The implementation of these sensor concepts prompts the development of wearable smart textiles. Thus, current sensing techniques and possibilities within photonic textiles are reviewed leading to multiparameter designs. Evaluation of these designs should show the great potential of optical fibers for the introduction into textiles especially due to the benefit of immunity to electromagnetic radiation. Still, further improvement of the signal-to-noise ratio is often necessary to develop a commercial monitoring system. PMID:25358557

  4. Optical fiber tactile sensor

    Science.gov (United States)

    Bejczy, A. K. (Inventor)

    1983-01-01

    A tactile sensor comprises an array of cells which are covered by an elastic membrane, having an exposed surface which is adapted to come in contact with an object. Light is conducted to each cell from a light source by an optical fiber which terminates at the cell. Reflected light from the cell is conducted by an optical fiber to a light processor, which senses changes in the light received thereby from an ambient level whenever an object comes in contact with the membrane surface above the cell.

  5. Directivity and Sensitivity of Fiber-Optic Cable Measuring Ground Motion using a Distributed Acoustic Sensing Array

    Science.gov (United States)

    Lancelle, C.; Lord, N. E.; Wang, H. F.; Fratta, D.; Nigbor, R. L.; Chalari, A.; Karaulanov, R.; Baldwin, J. A.; Castongia, E.

    2014-12-01

    Distributed acoustic sensing (DAS) is a relatively recent development for measurement of ground motion by using a fiber-optic cable itself as the sensor. In September 2013 a field test was conducted at the NEES@UCSB Garner Valley field site in Southern California incorporating DAS technology. A 762 meter long fiber-optic cable was trenched to a depth of about 0.3 m in a rectangular design with two interior diagonal segments. Existing instruments at the field site include the Garner Valley Downhole Array (GVDA) surface and borehole accelerometers and pore pressure transducers. A PASSCAL seismometer array and four NEES@UCLA tri-axial accelerometers were also deployed along the two interior diagonal segments. These sensors also recorded most of the source events. One goal of the field test was to study the response of the fiber-optic cable to various vibration sources, including a 45 kN shear shaker and a smaller 450 N portable mass shaker, both of which were available through NEES@UCLA. In addition to the shear sources, signals were recorded from a mini-Vibe source and hammer blows on a steel plate. The focus of this study is on the directivity and the sensitivity of the fiber-optic cable and the distributed acoustic sensor. Preliminary results indicate that the fiber-optic cable is most effective if oriented in the direction of maximum strain. Even with the directional response, signals were recorded throughout the array for different cable orientations at distances up to two-hundred meters. Move-out of different phases could be seen over several meters of traces recorded one-meter apart. Sensitivity of the fiber-optic cable relative to the other instruments is also presented.

  6. Fiber optic monitoring device

    Science.gov (United States)

    Samborsky, James K. (605 Groves Blvd., N. Augusta, SC 29841)

    1993-01-01

    A device for the purpose of monitoring light transmissions in optical fibers comprises a fiber optic tap that optically diverts a fraction of a transmitted optical signal without disrupting the integrity of the signal. The diverted signal is carried, preferably by the fiber optic tap, to a lens or lens system that disperses the light over a solid angle that facilitates viewing. The dispersed light indicates whether or not the monitored optical fiber or system of optical fibers is currently transmitting optical information.

  7. Advantage of multi-mode sapphire optical fiber for evanescent-field SERS sensing.

    Czech Academy of Sciences Publication Activity Database

    Chen, H.; Tian, F.; Chi, J.; Ka?ka, Ji?í; Du, H.

    2014-01-01

    Ro?. 39, ?. 20 (2014), 5822-5825. ISSN 0146-9592 R&D Projects: GA MŠk(CZ) LH11038 Institutional support: RVO:67985882 Keywords : Fiber optics sensors * Backscattering * Nanomaterials Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.292, year: 2014

  8. Advances in Using Fiber-Optic Distributed Temperature Sensing to Identify the Mixing of Waters

    Science.gov (United States)

    Briggs, M. A.; Day-Lewis, F. D.; Rosenberry, D. O.; Harvey, J. W.; Lane, J. W., Jr.; Hare, D. K.; Boutt, D. F.; Voytek, E. B.; Buckley, S.

    2014-12-01

    Fiber-optic distributed temperature sensing (FO-DTS) provides thermal data through space and time along linear cables. When installed along a streambed, FO-DTS can capture the influence of upwelling groundwater (GW) as thermal anomalies. The planning of labor-intensive physical measurements can make use of FO-DTS data to target areas of focused GW discharge that can disproportionately affect surface-water (SW) quality and temperature. Typical longitudinal FO-DTS spatial resolution ranges 0.25 to1.0 m, and cannot resolve small-scale water-column mixing or sub-surface diurnal fluctuations. However, configurations where the cable is wrapped around rods can improve the effective vertical resolution to sub-centimeter scales, and the pipes can be actively heated to induce a thermal tracer. Longitudinal streambed and high-resolution vertical arrays were deployed at the upper Delaware River (PA, USA) and the Quashnet River (MA, USA) for aquatic habitat studies. The resultant datasets exemplify the varied uses of FO-DTS. Cold anomalies found along the Delaware River steambed coincide with zones of known mussel populations, and high-resolution vertical array data showed relatively stable in-channel thermal refugia. Cold anomalies at the Quashnet River identified in 2013 were found to persist in 2014, and seepage measurements and water samples at these locations showed high GW flux with distinctive chemistry. Cable location is paramount to seepage identification, particularly in faster flowing deep streams such as the Quashnet and Delaware Rivers where steambed FO-DTS identified many seepage zones with no surface expression. The temporal characterization of seepage dynamics are unique to FO-DTS. However, data from Tidmarsh Farms, a cranberry bog restoration site in MA, USA indicate that in slower flowing shallow steams GW inflow affects surface temperature; therefore infrared imaging can provide seepage location information similar to FO-DTS with substantially less effort.

  9. The fiber-optic gyroscope, a century after Sagnac's experiment: The ultimate rotation-sensing technology?

    Science.gov (United States)

    Lefèvre, Hervé C.

    2014-12-01

    Taking advantage of the development of optical-fiber communication technologies, the fiber-optic gyroscope (often abbreviated FOG) started to be investigated in the mid-1970s, opening the way for a fully solid-state rotation sensor. It was firstly seen as dedicated to medium-grade applications (1 ° / h range), but today, it reaches strategic-grade performance (10-4 ° / h range) and surpasses its well-established competitor, the ring-laser gyroscope, in terms of bias noise and long-term stability. Further progresses remain possible, the challenge being the ultimate inertial navigation performance of one nautical mile per month corresponding to a long-term bias stability of 10-5 ° / h. This paper is also the opportunity to recall the historical context of Sagnac's experiment, the origin of all optical gyros. xml:lang="fr"

  10. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III

    2004-07-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Alkali salts of Mo{sub 6}Cl{sub 12} were synthesized and heated to 280 C for one hour in air. Optical measurements of the thermally treated material confirm the potential of the salts as lumophores in high temperature fiber optic sensors. In addition sol-gel films containing Mo{sub 6}Cl{sub 12} were dip coated on quartz substrates and heated at 200 C for one hour. Conditions were developed for successfully immobilizing monomeric complexes that are compatible with sol-gel processing.

  11. Infrared Fiber Optic Sensors

    Science.gov (United States)

    1997-01-01

    Successive years of Small Business Innovation Research (SBIR) contracts from Langley Research Center to Sensiv Inc., a joint venture between Foster-Miller Inc. and Isorad, Ltd., assisted in the creation of remote fiber optic sensing systems. NASA's SBIR interest in infrared, fiber optic sensor technology was geared to monitoring the curing cycles of advanced composite materials. These funds helped in the fabrication of an infrared, fiber optic sensor to track the molecular vibrational characteristics of a composite part while it is being cured. Foster-Miller ingenuity allowed infrared transmitting optical fibers to combine with Fourier Transform Infrared spectroscopy to enable remote sensing. Sensiv probes operate in the mid-infrared range of the spectrum, although modifications to the instrument also permits its use in the near-infrared region. The Sensiv needle-probe is built to be placed in a liquid or powder and analyze the chemicals in the mixture. Other applications of the probe system include food processing control; combustion control in furnaces; and maintenance problem solving.

  12. Drastic sensitivity enhancement of temperature sensing based on multimodal interference in polymer optical fibers

    Science.gov (United States)

    Numata, Goki; Hayashi, Neisei; Tabaru, Marie; Mizuno, Yosuke; Nakamura, Kentaro

    2015-07-01

    It has been reported that temperature sensors based on modal interference in perfluorinated graded-index polymer optical fibers show extremely high temperature sensitivity at room temperature. In this work, we confirm that the temperature sensitivity (absolute value) is significantly enhanced when the temperature increases toward ?70 °C, which is close to the glass-transition temperature of the core polymer. When the core diameter is 62.5 µm, the sensitivity at 72 °C at 1300 nm is 202 nm/°C/m, which is approximately 26 times the value obtained at room temperature and >7000 times the highest value previously reported using a silica multimode fiber.

  13. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III; Po Zhang

    2005-10-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Previously we immobilized the potassium salt of a molybdenum cluster, K{sub 2}M{sub 6}Cl{sub 14}, in a sol-gel matrix and showed that the luminescence is stable after 54 hours at 200 C, but the quenching ratios were low and the films delaminated after thermal cycling due to densification of the matrix. Three new approaches to solve decreased quenching over time and delamination of films off fiber tips were investigated. In the first approach K{sub 2}Mo{sub 6}Cl{sub 14} embedded in cured sol-gel particles were incorporated into a TEOS based sol-gel. These gave enhanced quenching (6x), but delaminated. Our second approach was to use a commercial cyanoacrylate glue to immobilize the particles onto the tip of an optical fiber. This gave better adhesion and good quenching initially, but eventually the glue degraded upon heating. Our third approach was to use a 55% OtMOS/ TEOS sol-gel binder. Films based on this new sol-gel binder show high quenching ({approx}6x) and superior mechanical stability even after thermal cycling. Sensor measurements on an optical fiber containing K{sub 2}Mo{sub 6}Cl{sub 14} embedded in cured sol-gel particles were obtained from 100 to 25 C. The signal intensity in nitrogen was stable at 2.8 {+-} 0.2 nW, and the quenching ratio (ratio of signal in N{sub 2} vs. 21 % O{sub 2}) varied from 4.4 to 6.9X. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  14. Optical Fiber Chemical Sensor with Sol-Gel Derived Refractive Material as Transducer for High Temperature Gas Sensing in Clean Coal Technology

    Energy Technology Data Exchange (ETDEWEB)

    Shiquan Tao

    2006-12-31

    The chemistry of sol-gel derived silica and refractive metal oxide has been systematically studied. Sol-gel processes have been developed for preparing porous silica and semiconductor metal oxide materials. Micelle/reversed micelle techniques have been developed for preparing nanometer sized semiconductor metal oxides and noble metal particles. Techniques for doping metal ions, metal oxides and nanosized metal particles into porous sol-gel material have also been developed. Optical properties of sol-gel derived materials in ambient and high temperature gases have been studied by using fiber optic spectroscopic techniques, such as fiber optic ultraviolet/visible absorption spectrometry, fiber optic near infrared absorption spectrometry and fiber optic fluorescence spectrometry. Fiber optic spectrometric techniques have been developed for investigating the optical properties of these sol-gel derived materials prepared as porous optical fibers or as coatings on the surface of silica optical fibers. Optical and electron microscopic techniques have been used to observe the microstructure, such as pore size, pore shape, sensing agent distribution, of sol-gel derived material, as well as the size and morphology of nanometer metal particle doped in sol-gel derived porous silica, the nature of coating of sol-gel derived materials on silica optical fiber surface. In addition, the chemical reactions of metal ion, nanostructured semiconductor metal oxides and nanometer sized metal particles with gas components at room temperature and high temperatures have also been investigated with fiber optic spectrometric methods. Three classes of fiber optic sensors have been developed based on the thorough investigation of sol-gel chemistry and sol-gel derived materials. The first group of fiber optic sensors uses porous silica optical fibers doped with metal ions or metal oxide as transducers for sensing trace NH{sub 3} and H{sub 2}S in high temperature gas samples. The second group of fiber optic sensors uses sol-gel derived porous silica materials doped with nanometer particles of noble metals in the form of fiber or coating for sensing trace H{sub 2}, NH{sub 3} and HCl in gas samples at for applications ambient temperature. The third classes of fiber optic sensors use sol-gel derived semiconductor metal oxide coating on the surface of silica optical fiber as transducers for selectively sensing H{sub 2}, CH{sub 4} and CO at high temperature. In addition, optical fiber temperature sensors use the fluorescence signal of rare-earth metal ions doped porous silica optical fiber or the optical absorption signal of thermochromic metal oxide materials coated on the surface of silica optical fibers have also been developed for monitoring gas temperature of corrosive gas. Based on the results obtained from this project, the principle of fiber optic sensor techniques for monitoring matrix gas components as well as trace components of coal gasification derived syngas has been established. Prototype sensors for sensing trace ammonia and hydrogen sulfide in gasification derived syngas have been built up in our laboratory and have been tested using gas samples with matrix gas composition similar to that of gasification derived fuel gas. Test results illustrated the feasibility of these sensors for applications in IGCC processes.

  15. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III; Po Zhang

    2005-04-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. One of the critical materials issues is to demonstrate that the luminescent cluster immobilized in the sol-gel porous support can withstand high temperature. At the same time the sol-gel matrix must have a high permeability to oxygen. Using a potassium salt of the molybdenum clusters, K{sub 2}Mo{sub 6}Cl{sub 14}, we have established the conditions necessary for deposition of optical quality sol-gel films. From spectroscopic measurements of the film we have shown that the cluster luminescence is stable following heat cycling of 54 hours at 200 C. Quenching of a factor of 1.5X between pure nitrogen and 21% oxygen was observed from in-situ measurements of films heated directly at 200 C. An automated system for characterizing fiber optic oxygen sensors up to 220 C with a temporal resolution better than 10 s is under construction. We estimate a signal of 6 x 10{sup 8} photons/s after complete quenching in 21% oxygen. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  16. Behavior of Random Hole Optical Fibers under Gamma Ray Irradiation and Its Potential Use in Radiation Sensing Applications

    Directory of Open Access Journals (Sweden)

    Anbo Wang

    2007-05-01

    Full Text Available Effects of radiation on sensing and data transmission components are of greatinterest in many applications including homeland security, nuclear power generation, andmilitary. A new type of microstructured optical fiber (MOF called the random hole opticalfiber (RHOF has been recently developed. The RHOFs can be made in many differentforms by varying the core size and the size and extent of porosity in the cladding region.The fibers used in this study possessed an outer diameter of 110 μm and a core ofapproximately 20 μm. The fiber structure contains thousands of air holes surrounding thecore with sizes ranging from less than 100 nm to a few μm. We present the first study ofthe behavior of RHOF under gamma irradiation. We also propose, for the first time to ourknowledge, an ionizing radiation sensor system based on scintillation light from ascintillator phosphor embedded within a holey optical fiber structure. The RHOF radiationresponse was compared to normal single mode and multimode commercial fibers(germanium doped core, pure silica cladding and to those of radiation resistant fibers (puresilica core with fluorine doped cladding fibers. The comparison was done by measuringradiation-induced absorption (RIA in all fiber samples at the 1550 nm wavelength window(1545 ± 25 nm. The study was carried out under a high-intensity gamma ray field from a 60Co source (with an exposure rate of 4x104 rad/hr at an Oak Ridge National Laboratory gamma ray irradiation facility. Linear behavior, at dose values less than 106 rad, was observed in all fiber samples except in the pure silica core fluorine doped cladding fiber which showed RIA saturation at 0.01 dB. RHOF samples demonstrated low RIA (0.02 and 0.005 dB compared to standard germanium doped core pure silica cladding (SMF and MMF fibers. Results also showed the possibility of post-fabrication treatment to improve the radiation resistance of the RHOF fibers.

  17. Optical fibre sensing of plasmas

    International Nuclear Information System (INIS)

    The progress of optical fiber technology for communications has induced an interest in, among others, the sensing of a wide range of physical, and chemical quantities. Any application of optical fibers that are crucial for communication are significant for sensing, e.g. small dimension, insulating materials, immunity to high voltage field etc. In the present paper basic points of optical fiber sensing are summarized. It is noted optical fiber sensors come in two forms, intrinsic and extrinsic. In the former the fiber itself works as sensing element, in addition to data transmission lines. In an intrinsic sensor, a single fiber transmits the light from the source to the detector and the light is modulated while it is in the fiber. On the other hand, in the extrinsic sensor, the light leaves the input fiber to be modulated before being collected by the second output fiber. Characteristic of the light that can be modulated are amplitude, phase, polarization, and wavelength. The paper describes the modulation in some details. (author)

  18. Highly distributed multi-point, temperature and pressure compensated, fiber optic oxygen sensors (FOxSense) for aircraft fuel tank environment and safety monitoring

    Science.gov (United States)

    Mendoza, Edgar A.; Kempen, Cornelia; Sun, Sunjian; Esterkin, Yan

    2014-09-01

    This paper describes recent progress towards the development and qualification of a highly distributed, multi-point, all optical pressure and temperature compensated, fiber optic oxygen sensor (FOxSense™) system for closed-loop monitoring and safety of the oxygen ullage environment inside fuel tanks of military and commercial aircraft. The alloptical FOxSense™ system uses a passive, multi-parameter (O2/T&P) fiber optic sensor probe with no electrical connections leading to the sensors install within the fuel tanks of an aircraft. The all optical sensor consists of an integrated multi-parameter fiber optic sensor probe that integrates a fuel insensitive fluorescence based optical oxygen optrode with built-in temperature and pressure optical optrodes for compensation of temperature and pressure variants induced in the fluorescence response of the oxygen optrode. The distributed (O2/T&P) fiber optic sensors installed in the fuel tanks of the aircraft are connected to the FOxSense optoelectronic system via a fiber optic cable conduit reaching to each fuel tank in the aircraft. A multichannel frequency-domain fiber optic sensor read-out (FOxSense™) system is used to interrogate the optical signal of all three sensors in real-time and to display the fuel tank oxygen environment suitable for aircraft status and alarm applications. Preliminary testing of the all optical fiber optic oxygen sensor have demonstrated the ability to monitor the oxygen environment inside a simulated fuel tank in the range of 0% O2 to 40% O2 concentrations, temperatures from (-) 40°C to (+) 60°C, and altitudes from 0-ft to 40,000-ft.

  19. Fiber optic calorimetry

    International Nuclear Information System (INIS)

    A twin-bridge calorimeter using optical fiber as the sensor element was constructed and tested. This system demonstrates the principle and capability of using fiber for heat-flow measurements of special nuclear material. This calorimeter uses piezoelectric-generated phase-carrier modulation with subsequent electronic signal processing to allow phase shifts as small as 1 microradian (?rad) to be measured. The sensing element consists of 21-m lengths of single-mode optical fiber wrapped around sample and reference chambers. The sensitivity of the calorimeter was determined to be 74 radians (rad) of phase shift per milliwatt of thermal power. One milliwatt of thermal power is equivalent to 400 mg of plutonium (6% 240Pu). The system noise base was about 0.2 rad, equivalent to about 1 mg of plutonium

  20. 300 m optic fiber Bragg grating temperature sensing system for seawater measurement

    Energy Technology Data Exchange (ETDEWEB)

    Li Xingrong; Li Yongqian; Wen Zhengyang, E-mail: li_xingrong@yahoo.cn [Department of Electronics and Communication Engineering, North China Electric Power University, Baoding 071003 (China)

    2011-02-01

    Optic fiber grating sensor is a research hotspot.It has been used on many occasions,and how to use it for ocean detection is a new research directions. The paper introduced the calibration work of FBG temperature sensors. It confirmed that from being armored package,the sensors can eliminate the water pressure effect. From the calibration experiment and data processing,60 sensors has little error were screened out for experiment. 300 m long optic fiber Bragg grating sensor array was designed.The marine experiments were achived in South China Sea with 300 meters long Bragg grating array and got the seawater profile temperature. Proposed the curve fitting method to process the data based on Levenberg-Marquardt algorithm. By curve fitting to the data acquired,the precision was better than 0.2 deg. C, which verified the effectiveness of the method.This result has practical value.

  1. 300 m optic fiber Bragg grating temperature sensing system for seawater measurement

    International Nuclear Information System (INIS)

    Optic fiber grating sensor is a research hotspot.It has been used on many occasions,and how to use it for ocean detection is a new research directions. The paper introduced the calibration work of FBG temperature sensors. It confirmed that from being armored package,the sensors can eliminate the water pressure effect. From the calibration experiment and data processing,60 sensors has little error were screened out for experiment. 300 m long optic fiber Bragg grating sensor array was designed.The marine experiments were achived in South China Sea with 300 meters long Bragg grating array and got the seawater profile temperature. Proposed the curve fitting method to process the data based on Levenberg-Marquardt algorithm. By curve fitting to the data acquired,the precision was better than 0.2 deg. C, which verified the effectiveness of the method.This result has practical value.

  2. Fiber optic connector

    Science.gov (United States)

    Rajic, Slobodan (Knoxville, TN); Muhs, Jeffrey D. (Lenior City, TN)

    1996-01-01

    A fiber optic connector and method for connecting composite materials within which optical fibers are imbedded. The fiber optic connector includes a capillary tube for receiving optical fibers at opposing ends. The method involves inserting a first optical fiber into the capillary tube and imbedding the unit in the end of a softened composite material. The capillary tube is injected with a coupling medium which subsequently solidifies. The composite material is machined to a desired configuration. An external optical fiber is then inserted into the capillary tube after fluidizing the coupling medium, whereby the optical fibers are coupled.

  3. Design of System for Monitoring Seepage of Levee Engineering Based on Distributed Optical Fiber Sensing Technology

    OpenAIRE

    Huaizhi Su; Yeyuan Kang

    2013-01-01

    Seepage is the major factor and monitoring index of levee safety. Leakage may be undetected by conventional monitoring methods and techniques, but optical fiber distributed temperature sensor (DTS) temperature measuring system can achieve real-time temperature monitoring in internal soil of levees. According to the temperature field obtained by DTS system, monitoring and inversion methods of seepage velocity based on double-line heat source and single-line heat source are introduced, respecti...

  4. Current sensing in magnetic fusion experiments by Faraday rotation in single-mode optical fibers

    International Nuclear Information System (INIS)

    We find that sensors exploiting the Faraday effect in single-mode optical fibers are practical means of measuring large currents in the MFE environment. Work still needs to be done to overcome the effects of linear birefringence. We have seen distortion caused by dynamic stress-induced birefringence and shown the importance of physically eliminating it because of the difficulty of treating it analytically

  5. Research on corrosion detection for steel reinforced concrete structures using the fiber optical white light interferometer sensing technique

    Science.gov (United States)

    Zhao, Xuefeng; Cui, Yanjun; Wei, Heming; Kong, Xianglong; Zhang, Pinglei; Sun, Changsen

    2013-06-01

    In this paper, a novel kind of steel rebar corrosion monitoring technique for steel reinforced concrete structures is proposed, designed, and tested. The technique is based on the fiber optical white light interferometer (WLI) sensing technique. Firstly, a feasibility test was carried out using an equal-strength beam for comparison of strain sensing ability between the WLI and a fiber Bragg grating (FBG). The comparison results showed that the sensitivity of the WLI is sufficient for corrosion expansion strain monitoring. Then, two WLI corrosion sensors (WLI-CSs) were designed, fabricated, and embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion. Their performance was studied in an accelerated electrochemical corrosion test. Experimental results show that expansion strain along the fiber optical coil winding area can be detected and measured accurately by the proposed sensor. The advantages of the proposed monitoring technique allow for quantitative corrosion expansion monitoring to be executed in real time for reinforced concrete structures and with low cost.

  6. Research on corrosion detection for steel reinforced concrete structures using the fiber optical white light interferometer sensing technique

    International Nuclear Information System (INIS)

    In this paper, a novel kind of steel rebar corrosion monitoring technique for steel reinforced concrete structures is proposed, designed, and tested. The technique is based on the fiber optical white light interferometer (WLI) sensing technique. Firstly, a feasibility test was carried out using an equal-strength beam for comparison of strain sensing ability between the WLI and a fiber Bragg grating (FBG). The comparison results showed that the sensitivity of the WLI is sufficient for corrosion expansion strain monitoring. Then, two WLI corrosion sensors (WLI-CSs) were designed, fabricated, and embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion. Their performance was studied in an accelerated electrochemical corrosion test. Experimental results show that expansion strain along the fiber optical coil winding area can be detected and measured accurately by the proposed sensor. The advantages of the proposed monitoring technique allow for quantitative corrosion expansion monitoring to be executed in real time for reinforced concrete structures and with low cost. (paper)

  7. Remote optical sensing on the nanometer scale with a bowtie aperture nano-antenna on a SNOM fiber tip

    CERN Document Server

    Atie, Elie M; Eter, Ali El; Salut, Roland; Nedeljkovic, Dusan; Tannous, Tony; Baida, Fadi I; Grosjean, Thierry

    2015-01-01

    Plasmonic nano-antennas have proven the outstanding ability of sensing chemical and physical processes down to the nano-meter scale. Sensing is usually achieved within the highly confined optical fields generated resonantly by the nano-antennas, i.e. in contact to the nano-structures. In these paper, We demonstrate the sensing capability of nano-antennas to their larger scale environment, well beyond their plasmonic confinement volume, leading to the concept of 'remote' (non contact) sensing on the nano-meter scale. On the basis of a bowtie-aperture nano-antenna (BNA) integrated at the apex of a SNOM fiber tip, we introduce an ultra-compact, move-able and background-free optical nano-sensor for the remote sensing of a silicon surface (up to distance of 300 nm). Sensitivity of the BNA to its large scale environment is high enough to expect the monitoring and control of the spacing between the nano-antenna and a silicon surface with sub-nano-meter accuracy. This work paves the way towards a new class of nano-po...

  8. An air flow sensor for neonatal mechanical ventilation applications based on a novel fiber-optic sensing technique

    International Nuclear Information System (INIS)

    In this work, a simple and low-cost air flow sensor, based on a novel fiber-optic sensing technique has been developed for monitoring air flows rates supplied by a neonatal ventilator to support infants in intensive care units. The device is based on a fiber optic sensing technique allowing (a) the immunity to light intensity variations independent by measurand and (b) the reduction of typical shortcomings affecting all biomedical fields (electromagnetic interference and patient electrical safety). The sensing principle is based on the measurement of transversal displacement of an emitting fiber-optic cantilever due to action of air flow acting on it; the fiber tip displacement is measured by means of a photodiode linear array, placed in front of the entrance face of the emitting optical fiber in order to detect its light intensity profile. As the measurement system is based on a detection of the illumination pattern, and not on an intensity modulation technique, it results less sensitive to light intensity fluctuation independent by measurand than intensity-based sensors. The considered technique is here adopted in order to develop two different configurations for an air flow sensor suitable for the measurement of air flow rates typically occurring during mechanical ventilation of newborns: a mono-directional and a bi-directional transducer have been proposed. A mathematical model for the air flow sensor is here proposed and a static calibration of two different arrangements has been performed: a measurement range up to 3.00 × 10?4 m3/s (18.0 l/min) for the mono-directional sensor and a measurement range of ±3.00 × 10?4 m3/s (±18.0 l/min) for the bi-directional sensor are experimentally evaluated, according to the air flow rates normally encountered during tidal breathing of infants with a mass lower than 10 kg. Experimental data of static calibration result in accordance with the proposed theoretical model: for the mono-directional configuration, the coefficient of determination r2 is equal to 0.997; for the bi-directional configuration, the coefficient of determination r2 is equal to 0.990 for positive flows (inspiration) and 0.988 for negative flows (expiration). Measurement uncertainty ?Q of air flow rate has been evaluated by means of the propagation of distributions and the percentage error in the arrangement of bi-directional sensor ranges from a minimum of about 0.5% at ?18.0 l/min to a maximum of about 9% at ?12.0 l/min.

  9. An air flow sensor for neonatal mechanical ventilation applications based on a novel fiber-optic sensing technique.

    Science.gov (United States)

    Battista, L; Sciuto, S A; Scorza, A

    2013-03-01

    In this work, a simple and low-cost air flow sensor, based on a novel fiber-optic sensing technique has been developed for monitoring air flows rates supplied by a neonatal ventilator to support infants in intensive care units. The device is based on a fiber optic sensing technique allowing (a) the immunity to light intensity variations independent by measurand and (b) the reduction of typical shortcomings affecting all biomedical fields (electromagnetic interference and patient electrical safety). The sensing principle is based on the measurement of transversal displacement of an emitting fiber-optic cantilever due to action of air flow acting on it; the fiber tip displacement is measured by means of a photodiode linear array, placed in front of the entrance face of the emitting optical fiber in order to detect its light intensity profile. As the measurement system is based on a detection of the illumination pattern, and not on an intensity modulation technique, it results less sensitive to light intensity fluctuation independent by measurand than intensity-based sensors. The considered technique is here adopted in order to develop two different configurations for an air flow sensor suitable for the measurement of air flow rates typically occurring during mechanical ventilation of newborns: a mono-directional and a bi-directional transducer have been proposed. A mathematical model for the air flow sensor is here proposed and a static calibration of two different arrangements has been performed: a measurement range up to 3.00 × 10(-4) m(3)?s (18.0 l?min) for the mono-directional sensor and a measurement range of ±3.00 × 10(-4) m(3)?s (±18.0 l?min) for the bi-directional sensor are experimentally evaluated, according to the air flow rates normally encountered during tidal breathing of infants with a mass lower than 10 kg. Experimental data of static calibration result in accordance with the proposed theoretical model: for the mono-directional configuration, the coefficient of determination r(2) is equal to 0.997; for the bi-directional configuration, the coefficient of determination r(2) is equal to 0.990 for positive flows (inspiration) and 0.988 for negative flows (expiration). Measurement uncertainty ?Q of air flow rate has been evaluated by means of the propagation of distributions and the percentage error in the arrangement of bi-directional sensor ranges from a minimum of about 0.5% at -18.0 l?min to a maximum of about 9% at -12.0 l?min. PMID:23556844

  10. Evaluation of temperature distribution sensing method for fast reactor using optical fiber

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Atsushi; Nakazawa, Masaharu [Tokyo Univ. (Japan); Ichige, Satoshi [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center

    1999-12-01

    Optical fiber sensors (OFSs) have many advantages like flexible configuration, intrinsic immunity for electromagnetic fields, and so on. For these reasons, it is very useful to apply OFSs to fast reactor plants for remote inspection and surveillance. However, under irradiation, because of radiation-induced transmission loss of optical fibers, OFSs have radiation-induced errors. Therefore, to apply OFSs to nuclear facilities, we have to estimate and correct the errors. In this report, Raman Distributed Temperature Sensor (RDTS; one of the OFSs) has been installed at the primary coolant loop of the experimental fast reactor JOYO of JNC (Japan Nuclear Cycle Development Institute). Two correction techniques (correction technique with two thermocouples and correction technique with loop arrangement) for radiation-induced errors have been developed and demonstrated. Because of the radiation-induced loss, measured temperature distributions had radiation-induced errors. However, during the continuous measurements with the total dose of more than 8 x 10{sup 3}[C/kg](3 x 10{sup 7}[R]), the radiation induced errors showed a saturation tendency. In case of the temperature distributions with fluorine doped fiber, with one of the correction techniques, the temperature errors reduced to 1{approx}2degC and the feasibility of the loss correction techniques was demonstrated. For these results, it can be said that RDTS can be applied as a temperature distribution monitor in harsh radiation environments like fast reactor plants. (author)

  11. Interferometric Fiber Optic Sensors

    Directory of Open Access Journals (Sweden)

    Hae Young Choi

    2012-02-01

    Full Text Available Fiber optic interferometers to sense various physical parameters including temperature, strain, pressure, and refractive index have been widely investigated. They can be categorized into four types: Fabry-Perot, Mach-Zehnder, Michelson, and Sagnac. In this paper, each type of interferometric sensor is reviewed in terms of operating principles, fabrication methods, and application fields. Some specific examples of recently reported interferometeric sensor technologies are presented in detail to show their large potential in practical applications. Some of the simple to fabricate but exceedingly effective Fabry-Perot interferometers, implemented in both extrinsic and intrinsic structures, are discussed. Also, a wide variety of Mach-Zehnder and Michelson interferometric sensors based on photonic crystal fibers are introduced along with their remarkable sensing performances. Finally, the simultaneous multi-parameter sensing capability of a pair of long period fiber grating (LPG is presented in two types of structures; one is the Mach-Zehnder interferometer formed in a double cladding fiber and the other is the highly sensitive Sagnac interferometer cascaded with an LPG pair.

  12. Optical Fiber Distributed Sensing Structural Health Monitoring (SHM) Strain Measurements Taken During Cryotank Y-Joint Test Article Load Cycling at Liquid Helium Temperatures

    Science.gov (United States)

    Allison, Sidney G.; Prosser, William H.; Hare, David A.; Moore, Thomas C.; Kenner, Winfred S.

    2007-01-01

    This paper outlines cryogenic Y-joint testing at Langley Research Center (LaRC) to validate the performance of optical fiber Bragg grating strain sensors for measuring strain at liquid helium temperature (-240 C). This testing also verified survivability of fiber sensors after experiencing 10 thermal cool-down, warm-up cycles and 400 limit load cycles. Graphite composite skins bonded to a honeycomb substrate in a sandwich configuration comprised the Y-joint specimens. To enable SHM of composite cryotanks for consideration to future spacecraft, a light-weight, durable monitoring technology is needed. The fiber optic distributed Bragg grating strain sensing system developed at LaRC is a viable substitute for conventional strain gauges which are not practical for SHM. This distributed sensing technology uses an Optical Frequency Domain Reflectometer (OFDR). This measurement approach has the advantage that it can measure hundreds of Bragg grating sensors per fiber and the sensors are all written at one frequency, greatly simplifying fiber manufacturing. Fiber optic strain measurements compared well to conventional strain gauge measurements obtained during these tests. These results demonstrated a high potential for a successful implementation of a SHM system incorporating LaRC's fiber optic sensing system on the composite cryotank and other future cryogenic applications.

  13. Data processing in safety monitoring for earth embankment dams using fully distributed sensing along optical fibers

    Science.gov (United States)

    Chen, A. H.; Zeng, H. Y.; Zhu, P. Y.; Leng, Y. B.

    2009-11-01

    In this study we present a method to sort measured-data and process signal for special hydrodynamic monitoring system based on distributed optical fiber sensors. The procedure consists of defining the attribute of the data, data processing and information matching. The data of for-processing-part are processed regularly, which directly provides results for the user from the monitoring system. These results go into the next step to add environmental parameters, which includes weather, special events and season information. Information fusion and matching operation of the result and environment information enhances the accuracy of hidden hazard early warning.

  14. Remote optical sensing on the nanometer scale with a bowtie aperture nano-antenna on a fiber tip of scanning near-field optical microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Atie, Elie M.; Xie, Zhihua; El Eter, Ali; Salut, Roland; Baida, Fadi I.; Grosjean, Thierry, E-mail: thierry.grosjean@univ-fcomte.fr [Institut FEMTO-ST, UMR CNRS 6174, Université de Franche-Comté, Département d' Optique P.M. Duffieux, 15B avenue des Montboucons, 25030 Besançon cedex (France); Nedeljkovic, Dusan [Lovalite s.a.s., 7 rue Xavier Marmier, 25000 Besançon (France); Tannous, Tony [Department of Physics, University of Balamand, P.O. Box 100 Tripoli (Lebanon)

    2015-04-13

    Plasmonic nano-antennas have proven the outstanding ability of sensing chemical and physical processes down to the nanometer scale. Sensing is usually achieved within the highly confined optical fields generated resonantly by the nano-antennas, i.e., in contact to the nanostructures. In this paper, we demonstrate the sensing capability of nano-antennas to their larger scale environment, well beyond their plasmonic confinement volume, leading to the concept of “remote” (non contact) sensing on the nanometer scale. On the basis of a bowtie-aperture nano-antenna (BNA) integrated at the apex of a SNOM (Scanning Near-field Optical Microscopy) fiber tip, we introduce an ultra-compact, moveable, and background-free optical nanosensor for the remote sensing of a silicon surface (up to distance of 300?nm). Sensitivity of the BNA to its large scale environment is high enough to expect the monitoring and control of the spacing between the nano-antenna and a silicon surface with sub-nanometer accuracy. This work paves the way towards an alternative class of nanopositioning techniques, based on the monitoring of diffraction-free plasmon resonance, that are alternative to nanomechanical and diffraction-limited optical interference-based devices.

  15. Remote optical sensing on the nanometer scale with a bowtie aperture nano-antenna on a fiber tip of scanning near-field optical microscopy

    Science.gov (United States)

    Atie, Elie M.; Xie, Zhihua; El Eter, Ali; Salut, Roland; Nedeljkovic, Dusan; Tannous, Tony; Baida, Fadi I.; Grosjean, Thierry

    2015-04-01

    Plasmonic nano-antennas have proven the outstanding ability of sensing chemical and physical processes down to the nanometer scale. Sensing is usually achieved within the highly confined optical fields generated resonantly by the nano-antennas, i.e., in contact to the nanostructures. In this paper, we demonstrate the sensing capability of nano-antennas to their larger scale environment, well beyond their plasmonic confinement volume, leading to the concept of "remote" (non contact) sensing on the nanometer scale. On the basis of a bowtie-aperture nano-antenna (BNA) integrated at the apex of a SNOM (Scanning Near-field Optical Microscopy) fiber tip, we introduce an ultra-compact, moveable, and background-free optical nanosensor for the remote sensing of a silicon surface (up to distance of 300 nm). Sensitivity of the BNA to its large scale environment is high enough to expect the monitoring and control of the spacing between the nano-antenna and a silicon surface with sub-nanometer accuracy. This work paves the way towards an alternative class of nanopositioning techniques, based on the monitoring of diffraction-free plasmon resonance, that are alternative to nanomechanical and diffraction-limited optical interference-based devices.

  16. Remote optical sensing on the nanometer scale with a bowtie aperture nano-antenna on a fiber tip of scanning near-field optical microscopy

    International Nuclear Information System (INIS)

    Plasmonic nano-antennas have proven the outstanding ability of sensing chemical and physical processes down to the nanometer scale. Sensing is usually achieved within the highly confined optical fields generated resonantly by the nano-antennas, i.e., in contact to the nanostructures. In this paper, we demonstrate the sensing capability of nano-antennas to their larger scale environment, well beyond their plasmonic confinement volume, leading to the concept of “remote” (non contact) sensing on the nanometer scale. On the basis of a bowtie-aperture nano-antenna (BNA) integrated at the apex of a SNOM (Scanning Near-field Optical Microscopy) fiber tip, we introduce an ultra-compact, moveable, and background-free optical nanosensor for the remote sensing of a silicon surface (up to distance of 300?nm). Sensitivity of the BNA to its large scale environment is high enough to expect the monitoring and control of the spacing between the nano-antenna and a silicon surface with sub-nanometer accuracy. This work paves the way towards an alternative class of nanopositioning techniques, based on the monitoring of diffraction-free plasmon resonance, that are alternative to nanomechanical and diffraction-limited optical interference-based devices

  17. Fiber Singular Optics

    OpenAIRE

    Volyar, A. V.

    2002-01-01

    The present review is devoted to the optical vortex behavior both in free space and optical fibers. The processes of the vortex transformations in perturbed optical fibers are analyzed on the base of the operator of the spin – orbit interaction in order to forecast the possible ways of manufacturing the vortex preserving fibers and their applications in supersensitive optical devices.

  18. Fiber optic Brillouin distributed sensing using phase-shift keying modulation techniques

    Science.gov (United States)

    Stiller, Birgit; Lee, Min W.; Nguyen, Duc Minh; Hauden, Jerôme; Mottet, Alexandre; Maillotte, Hervé; Sylvestre, Thibaut

    2012-04-01

    In this work we demonstrate two new BOTDA sensing systems based on differential (DPSK) and quadrature (QPSK) phase-shift keying modulation techniques with enhanced performances. First we demonstrate Brillouin echoes distributed sensing (BEDS) with centimeter resolution using a single intensity DPSK modulator for the pump pulse. The optical ?-phase pulse is directly generated at the end of an intensity pulse using DPSK technique. This allows an easy adjustment of the delay between the intensity and phase pulse and improves the optical loss of the pump. The second technique uses an optical QPSK modulator (I & Q modulator) as a single sideband (SSB) modulator. The advantage of I & Q modulator compared to dual-drive modulator lies on the high performance of carrier suppression of 55 dB as well as side-mode suppression of 40 dB at 1535 nm. Besides the filter that chooses either the Stokes or anti-Stokes component before detecting the Brillouin response on the photodiode is no more needed. By use of the I & Q modulator the performance of BOTDA using either Stokes or anti-Stokes component is shown and discussed.

  19. Application of Fiber Optic Instrumentation

    Science.gov (United States)

    Richards, William Lance; Parker, Allen R., Jr.; Ko, William L.; Piazza, Anthony; Chan, Patrick

    2012-01-01

    Fiber optic sensing technology has emerged in recent years offering tremendous advantages over conventional aircraft instrumentation systems. The advantages of fiber optic sensors over their conventional counterparts are well established; they are lighter, smaller, and can provide enormous numbers of measurements at a fraction of the total sensor weight. After a brief overview of conventional and fiber-optic sensing technology, this paper presents an overview of the research that has been conducted at NASA Dryden Flight Research Center in recent years to advance this promising new technology. Research and development areas include system and algorithm development, sensor characterization and attachment, and real-time experimentally-derived parameter monitoring for ground- and flight-based applications. The vision of fiber optic smart structure technology is presented and its potential benefits to aerospace vehicles throughout the lifecycle, from preliminary design to final retirement, are presented.

  20. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III

    2004-04-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. The luminescence of Mo{sub 6}Cl{sub 12} immobilized in a sol-gel matrix was measured as a function of heater temperature up to 200 C, in an inert environment. While the luminescence decreased with temperature, the integrated intensity at 200 C should be sufficient to enable detection of the luminescence in a fiber geometry. Previously we found that aging Mo{sub 6}Cl{sub 12} at temperatures above 250 C converts the canary yellow Mo{sub 6}Cl{sub 12} to a non-luminescent gray solid. Optical and thermal aging experiments show that the alkali metal salts of Mo{sub 6}Cl{sub 12} have higher thermal stabilities and remain luminescent after aging at 280 C.

  1. Lamb wave-based damage detection of composite shells using high-speed fiber-optic sensing

    Science.gov (United States)

    Sotoudeh, Vahid; Black, Richard J.; Moslehi, Behzad; Qiao, Pizhong

    2014-04-01

    A Lamb wave-based damage identification method called damage imaging method for composite shells is presented. A damage index (DI) is generated from the delay matrix of the Lamb wave response signals, and it is used to indicate the location and approximate area of the damage. A piezoelectric actuator is employed to generate the Lamb waves that are subsequently captured by a fiber Bragg grating (FBG) sensor element array multiplexed in a single fiber connected to a high-speed fiber-optic sensor system. The high-speed sensing is enabled by an innovative parallel-architecture optical interrogation system. The viability of this method is demonstrated by analyzing the numerical and experimental Lamb wave response signals from laminated composite shells. The technique only requires the response signals from the plate after damage, and it is capable of performing near real-time damage identification. This study sheds some light on the application of a Lamb wave-based damage detection algorithm for curved plate/shell-type structures by using the relatively low frequency (around 100 kHz) Lamb wave response and the high-speed FBG sensor system.

  2. Fiber Optics Instrumentation Development

    Science.gov (United States)

    Chan, Patrick Hon Man; Parker, Allen R., Jr.; Richards, W. Lance

    2010-01-01

    This is a general presentation of fiber optics instrumentation development work being conducted at NASA Dryden for the past 10 years and recent achievements in the field of fiber optics strain sensors.

  3. Fiber Optics Technology.

    Science.gov (United States)

    Burns, William E.

    1986-01-01

    Discusses various applications of fiber optics technology: information systems, industrial robots, medicine, television, transportation, and training. Types of jobs that will be available with fiber optics training (such as electricians and telephone cable installers and splicers) are examined. (CT)

  4. Drastic sensitivity enhancement of temperature sensing based on modal interference in plastic optical fibers

    Science.gov (United States)

    Numata, G.; Hayashi, N.; Tabaru, M.; Mizuno, Y.; Nakamura, K.

    2015-09-01

    It has been reported that temperature sensors based on modal interference in perfluorinated graded-index (GI) plastic optical fibers (POFs) show the world's highest temperature sensitivity of +49.8 nm/°C/m at 1300 nm at room temperature, which is over 1800 times the value in silica multimode fibers (MMFs). In this work, we newly find that the temperature sensitivity (absolute value) is significantly enhanced with increasing temperature toward ~70°C, which is close to the glass-transition temperature of the core polymer. When the core diameter is 62.5 ?m, the sensitivity at 72 °C at 1300 nm is +202 nm/°C/m, which is approximately 26 times the value obtained at room temperature and even over 7000 times the highest value previously reported using a silica MMF. As the glass-transition temperature of polymers can be generally set to an arbitrary value, this characteristic could be used to develop POF-based temperature sensors with ultra-high sensitivity not only at ~70°C but at arbitrary temperature in future.

  5. Improvement of plastic optical fiber microphone based on moisture pattern sensing in devoiced breath

    Science.gov (United States)

    Taki, Tomohito; Honma, Satoshi; Morisawa, Masayuki; Muto, Shinzo

    2008-03-01

    Conversation is the most practical and common form in communication. However, people with a verbal handicap feel a difficulty to produce words due to variations in vocal chords. This research leads to develop a new devoiced microphone system based on distinguishes between the moisture patterns for each devoiced breaths, using a plastic optical fiber (POF) moisture sensor. In the experiment, five POF-type moisture sensors with fast response were fabricated by coating swell polymer with a slightly larger refractive index than that of fiber core and were set in front of mouth. When these sensors are exposed into humid air produced by devoiced breath, refractive index in cladding layer decreases by swelling and then the POF sensor heads change to guided type. Based on the above operation principle, the output light intensities from the five sensors set in front of mouth change each other. Using above mentioned output light intensity patterns, discernment of devoiced vowels in Japanese (a,i,u,e,o) was tried by means of DynamicProgramming-Matching (DP-matching) method. As the result, distinction rate over 90% was obtained to Japanese devoiced vowels. Therefore, using this system and a voice synthesizer, development of new microphone for the person with a functional disorder in the vocal chords seems to be possible.

  6. Fiber optic sensing of relative humidity using a twin low coherence interferometer

    Scientific Electronic Library Online (English)

    A.V., Khomenko; J., Tapia-Mercado; M.A., García-Zarate.

    2010-06-01

    Full Text Available En este trabajo se describe un sensor de humedad de fibra óptica que consiste en dos interferómetros de Sagnac con secciones de fibra óptica torcida de alta birrefringencia. Las fibras birrefringentes sirven como elementos sensibles a la temperatura que permiten medir simultáneamente la temperatura [...] de bulbo seco y bulbo mojado. Se describe el método para interrogación de dos sensores de temperatura basados en la interferometría de baja coherencia con procesamiento de señales en el dominio espectral. La incertidumbre de la medición, estimada experimentalmente, es de 0.01°C y 4% para mediciones de temperatura y humedad, respectivamente. Abstract in english A fiber-optic implementation of psychrometer is reported. It consists of two Sagnac interferometers with twisted highly birefringent fiber that is used as a temperature sensitive element. One interferometer is used for dry-bulb temperature measurement and the other is for wet-bulb temperature monito [...] ring. The interrogation technique for low coherence interferometric sensor with signal processing in spectral domain is described. The measurement uncertainties for temperature and relative humidity measurements no worse than 0.01°C and 4%, respectively, have been achieved experimentally.

  7. Multipoint Pressure and Temperature Sensing Fiber Optic Cable for Monitoring CO2 Sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Challener, William

    2014-12-31

    This report describes the work completed on contract DE-FE0010116. The goal of this two year project was to develop and demonstrate in the laboratory a highly accurate multi-point pressure measurement fiber optic cable based on MEMS pressure sensors suitable for downhole deployment in a CO2 sequestration well. The sensor interrogator was also to be demonstrated in a remote monitoring system and environmental testing was to be completed to indicate its downhole survivability over a lengthy period of time (e.g., 20 years). An interrogator system based on a pulsed laser excitation was shown to be capable of multiple (potentially 100+) simultaneous sensor measurements. Two sensors packages were completed and spliced in a cable onto the same fiber and measured. One sensor package was subsequently measured at high temperatures and pressures in supercritical CO2, while the other package was measured prior and after being subjected to high torque stresses to mimic downhole deployment. The environmental and stress tests indicated areas in which the package design should be further improved.

  8. Monitoring of Thermal Protection Systems Using Robust Self-Organizing Optical Fiber Sensing Networks

    Science.gov (United States)

    Richards, Lance

    2013-01-01

    The general aim of this work is to develop and demonstrate a prototype structural health monitoring system for thermal protection systems that incorporates piezoelectric acoustic emission (AE) sensors to detect the occurrence and location of damaging impacts, and an optical fiber Bragg grating (FBG) sensor network to evaluate the effect of detected damage on the thermal conductivity of the TPS material. Following detection of an impact, the TPS would be exposed to a heat source, possibly the sun, and the temperature distribution on the inner surface in the vicinity of the impact measured by the FBG network. A similar procedure could also be carried out as a screening test immediately prior to re-entry. The implications of any detected anomalies in the measured temperature distribution will be evaluated for their significance in relation to the performance of the TPS during re-entry. Such a robust TPS health monitoring system would ensure overall crew safety throughout the mission, especially during reentry

  9. The Fiber Optic Connection.

    Science.gov (United States)

    Reese, Susan

    2003-01-01

    Describes the fiber optics programs at the Career and Technical Center in Berlin, Pennsylvania and the Charles S. Monroe Technology Center in Loudoun County, Virginia. Discusses the involvement of the Fiber Optic Association with education, research and development, manufacturing, sales, distribution, installation, and maintenance of fiber optic

  10. Application of optical fiber distributed sensing to health monitoring of concrete structures

    Science.gov (United States)

    Villalba, Sergi; Casas, Joan R.

    2013-08-01

    The use of Optical Backscatter Reflectometer (OBR) sensors is a promising measurement technology for Structural Health Monitoring (SHM) as it offers the possibility of continuous monitoring of strain and temperature along the fiber. Several applications to materials used in the aeronautical construction have demonstrated the feasibility of such technique. These materials (composites, steel, aluminum) apart from having a smooth surface where the bonding of the sensor is easily carried out, they also have a continuous strain field when subject to external loading and therefore the bonding of the OBR on the material surface is not in danger for high levels of loading as the OBR can easily follow the strain in the material. The application of such type of sensor to concrete structures may present some difficulties due to (1) the roughness of the concrete surface and the heterogeneity due to the presence of aggregates of several sizes, (2) the fact that reinforced concrete cracks at very low level of load, appearance of a discontinuity in the surface and the strain field that may provoke a break or debonding of the optical fiber. However the feasibility of using OBR in the SHM of civil engineering constructions made of concrete is also of great interest, mainly because in this type of structures it is impossible to know where the crack may appear and therefore severe cracking (dangerous for the structure operation) can appear without warning of the monitoring if sensors are not placed in the particular location where the crack appears. In order to explore the potentiality of detecting cracks as they appear without failure or debonding, as well as the compatibility of the OBR bonding to the concrete surfaces, this paper shows the test carried out in the loading up to failure of a concrete slab.

  11. Subsea downhole optical sensing

    International Nuclear Information System (INIS)

    The potential for subsea downhole optical fibre sensing to optimize hydrocarbon production and hence contribute to enhanced oil recovery is described. The components of susbea downhole optical sensing systems are reviewed and the performance of a new subsea optical fibre feed-through for downhole optical fibre sensing reported.

  12. Sapphire ball lensed fiber probe for common-path optical coherence tomography in ocular imaging and sensing

    Science.gov (United States)

    Zhao, Mingtao; Huang, Yong; Kang, Jin U.

    2013-03-01

    We describe a novel common-path optical coherence tomography (CP-OCT) fiber probe design using a sapphire ball lens for cross-sectional imaging and sensing in retina vitrectomy surgery. Single mode Gaussian beam (TEM00) simulation was used to optimize lateral resolution and working distance (WD) of the common-path probe. A theoretical sensitivity model for CP-OCT was prosed to assess its optimal performance based an unbalanced photodetector configuration. Two probe designs with working distances (WD) 415?m and 1221?m and lateral resolution 11?m and 18?m, respectively were implemented with sensitivity up to 88dB. The designs are also fully compatible with conventional Michelson interferometer based OCT configurations. The reference plane of the probe, located at the distal beam exit interface of the single mode fiber (SMF), was encased within a 25-gauge hypodermic needle by the sapphire ball lens facilitates its applications in bloody and harsh environments. The performances of the fiber probe with 11?m of lateral resolution and 19?m of axial resolution were demonstrated by cross-sectional imaging of a cow cornea and retina in vitro with a 1310nm swept source OCT system. This probe was also attached to a piezoelectric motor for active compensation of physiological tremor for handheld retinal surgical tools.

  13. Sapphire ball lensed fiber probe for common-path optical coherence tomography in ocular imaging and sensing.

    Science.gov (United States)

    Zhao, Mingtao; Huang, Yong; Kang, Jin U

    2013-03-26

    We describe a novel common-path optical coherence tomography (CP-OCT) fiber probe design using a sapphire ball lens for cross-sectional imaging and sensing in retina vitrectomy surgery. Single mode Gaussian beam (TEM(00)) simulation was used to optimize lateral resolution and working distance (WD) of the common-path probe. A theoretical sensitivity model for CP-OCT was prosed to assess its optimal performance based an unbalanced photodetector configuration. Two probe designs with working distances (WD) 415?m and 1221?m and lateral resolution 11?m and 18?m, respectively were implemented with sensitivity up to 88dB. The designs are also fully compatible with conventional Michelson interferometer based OCT configurations. The reference plane of the probe, located at the distal beam exit interface of the single mode fiber (SMF), was encased within a 25-gauge hypodermic needle by the sapphire ball lens facilitates its applications in bloody and harsh environments. The performances of the fiber probe with 11?m of lateral resolution and 19?m of axial resolution were demonstrated by cross-sectional imaging of a cow cornea and retina in vitro with a 1310nm swept source OCT system. This probe was also attached to a piezoelectric motor for active compensation of physiological tremor for handheld retinal surgical tools. PMID:24392202

  14. Nonlinear Fiber Optics

    Science.gov (United States)

    Agrawal, Govind P.

    Nonlinear fiber optics concerns with the nonlinear optical phenomena occurring inside optical fibers. Although the field of nonlinear optics traces its beginning to 1961, when a ruby laser was first used to generate the second-harmonic radiation inside a crystal [1], the use of optical fibers as a nonlinear medium became feasible only after 1970 when fiber losses were reduced to below 20 dB/km [2]. Stimulated Raman and Brillouin scatterings in single-mode fibers were studied as early as 1972 [3] and were soon followed by the study of other nonlinear effects such as self- and cross-phase modulation and four-wave mixing [4]. By 1989, the field of nonlinear fiber optics has advanced enough that a whole book was devoted to it [5]. This book or its second edition has been translated into Chinese, Japanese, and Russian languages, attesting to the worldwide activity in the field of nonlinear fiber optics.

  15. Statistical mapping of zones of focused groundwater/surface-water exchange using fiber-optic distributed temperature sensing

    Science.gov (United States)

    Mwakanyamale, Kisa; Day-Lewis, Frederick D.; Slater, Lee D.

    2013-01-01

    Fiber-optic distributed temperature sensing (FO-DTS) increasingly is used to map zones of focused groundwater/surface-water exchange (GWSWE). Previous studies of GWSWE using FO-DTS involved identification of zones of focused GWSWE based on arbitrary cutoffs of FO-DTS time-series statistics (e.g., variance, cross-correlation between temperature and stage, or spectral power). New approaches are needed to extract more quantitative information from large, complex FO-DTS data sets while concurrently providing an assessment of uncertainty associated with mapping zones of focused GSWSE. Toward this end, we present a strategy combining discriminant analysis (DA) and spectral analysis (SA). We demonstrate the approach using field experimental data from a reach of the Columbia River adjacent to the Hanford 300 Area site. Results of the combined SA/DA approach are shown to be superior to previous results from qualitative interpretation of FO-DTS spectra alone.

  16. Optical Remote Sensing Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Optical Remote Sensing Laboratory deploys rugged, cutting-edge electro-optical instrumentation for the collection of various event signatures, with expertise in...

  17. An Efficient Wavelength variation approach for Bend Sensing in Single mode-Multimode-Single mode Optical Fiber Sensors

    Directory of Open Access Journals (Sweden)

    Abdul Samee Khan

    2012-09-01

    Full Text Available Several aspects of the SMS edge filters have been investigated, including the effect of bending the SMS fiber cores due to fabrication tolerances, polarization dependence, and temperature dependence. These aspects can impair the performance of a wavelength measurement system. There are several approaches which have been proposed and demonstrated to achieve high resolution and accuracy of wavelength measurement. Bending effects due to the splicing process on the spectral characteristics of SMS fibre structure-based edge filters are investigated experimentally with the help of MATLAB. A limit for the tolerable of the cores of an SMS fibre structure-based edge filter is proposed, beyond which the edge filter’s spectral performance degrades unacceptably. We use Wavelength variation approach by which we reduce the power loss due to the bending in the optical fiber. Due to the power loss the power transmission is increases and efficiency reduces. So by wavelength variation approach we developed an efficient spectrometer capable of performing a wide variety of coherent multidimensional measurements at optical wavelengths. In this approach we fixed the power and perform variation in the wavelength to sense the bending accurately. The two major components of the largely automated device are a spatial beam shaper which controls the beam geometry and a spatiotemporal pulse shaper which controls the temporal waveform of the femtosecond pulse in each beam. By which we sense the distortion to reduce the power transmission. We apply our algorithm for performing several comparison considerations which shows the performance of our algorithm which is better in comparison to the previous work.

  18. Fiber optics engineering

    CERN Document Server

    Azadeh, Mohammad

    2009-01-01

    Covering fiber optics from an engineering perspective, this text emphasizes data conversion between electrical and optical domains. Techniques to improve the fidelity of this conversion (from electrical to optical domain, and vice versa) are also covered.

  19. Improving Photovoltaic Energy Production with Fiber-Optic Distributed Temperature Sensing

    Science.gov (United States)

    Hausner, M. B.; Berli, M.

    2014-12-01

    The efficiency of solar photovoltaic (PV) generators declines sharply with increased temperatures. Peak solar exposure often occurs at the same time as peak temperatures, but solar PV installations are typically designed based on solar angle. In temperate areas, the peak temperatures may not be high enough to induce significant efficiency losses. In some of the areas with the greatest potential for solar development, however, summer air temperatures regularly reach 45 °C and PV panel temperatures exceed the air temperatures. Here we present a preliminary model of a PV array intended to optimize solar production in a hot and arid environment. The model begins with the diurnal and seasonal cycles in the angle and elevation of the sun, but also includes a meteorology-driven energy balance to project the temperatures of the PV panels and supporting structure. The model will be calibrated and parameterized using a solar array at the Desert Research Institute's (DRI) Renewable Energy Deployment and Display (REDD) facility in Reno, Nevada, and validated with a similar array at DRI's Las Vegas campus. Optical fibers will be installed on the PV panels and structural supports and interrogated by a distributed temperature sensor (DTS) to record the spatial and temporal variations in temperature. Combining the simulated panel temperatures, the efficiency-temperature relationship for the panels, and the known solar cycles at a site will allow us to optimize the design of future PV collectors (i.e., the aspect and angle of panels) for given production goals.

  20. Monitoring of Thermal Protection Systems and MMOD using Robust Self-Organizing Optical Fiber Sensing Networks

    Science.gov (United States)

    Richards, Lance

    2014-01-01

    The general aim of this work is to develop and demonstrate a prototype structural health monitoring system for thermal protection systems that incorporates piezoelectric acoustic emission (AE) sensors to detect the occurrence and location of damaging impacts, such as those from Micrometeoroid Orbital Debris (MMOD). The approach uses an optical fiber Bragg grating (FBG) sensor network to evaluate the effect of detected damage on the thermal conductivity of the TPS material. Following detection of an impact, the TPS would be exposed to a heat source, possibly the sun, and the temperature distribution on the inner surface in the vicinity of the impact measured by the FBG network. A similar procedure could also be carried out as a screening test immediately prior to re-entry. The implications of any detected anomalies in the measured temperature distribution will be evaluated for their significance in relation to the performance of the TPS during reentry. Such a robust TPS health monitoring system would ensure overall crew safety throughout the mission, especially during reentry.

  1. Fiber optic micro accelerometer

    Science.gov (United States)

    Swierkowski, Steve P.

    2005-07-26

    An accelerometer includes a wafer, a proof mass integrated into the wafer, at least one spring member connected to the proof mass, and an optical fiber. A Fabry-Perot cavity is formed by a partially reflective surface on the proof mass and a partially reflective surface on the end of the optical fiber. The two partially reflective surfaces are used to detect movement of the proof mass through the optical fiber, using an optical detection system.

  2. A Bragg Wavelength-Insensitive Fiber Bragg Grating Ultrasound Sensing System that Uses a Broadband Light and No Optical Filter

    Directory of Open Access Journals (Sweden)

    Hiroshi Tsuda

    2011-07-01

    Full Text Available An optical filter is incorporated in a conventional ultrasound detection system that uses a fiber Bragg grating (FBG and broadband light source, to demodulate the FBG sensor signal. A novel ultrasound sensing system that does not require an optical filter is presented herein. Ultrasound could be detected via the application of signal processing techniques, such as signal averaging and frequency filters, to the photodetector output that corresponds to the intensity of the reflected light from a broadband light-illuminated FBG. Ultrasonic sensitivity was observed to be enhanced when an FBG was installed as a resonant sensor. This FBG ultrasound detection system is small and cheap to fabricate because it does not use a demodulating optical filter. The experimental results demonstrate that this system could be applied to ultrasonic damage inspection and acoustic emission measurements. Furthermore, this system was able to detect ultrasound despite the amount of strain or temperature that was applied to the FBG sensor because the ultrasound detection was not sensitive to the Bragg wavelength of the FBG sensor.

  3. A Bragg wavelength-insensitive fiber Bragg grating ultrasound sensing system that uses a broadband light and no optical filter.

    Science.gov (United States)

    Tsuda, Hiroshi

    2011-01-01

    An optical filter is incorporated in a conventional ultrasound detection system that uses a fiber Bragg grating (FBG) and broadband light source, to demodulate the FBG sensor signal. A novel ultrasound sensing system that does not require an optical filter is presented herein. Ultrasound could be detected via the application of signal processing techniques, such as signal averaging and frequency filters, to the photodetector output that corresponds to the intensity of the reflected light from a broadband light-illuminated FBG. Ultrasonic sensitivity was observed to be enhanced when an FBG was installed as a resonant sensor. This FBG ultrasound detection system is small and cheap to fabricate because it does not use a demodulating optical filter. The experimental results demonstrate that this system could be applied to ultrasonic damage inspection and acoustic emission measurements. Furthermore, this system was able to detect ultrasound despite the amount of strain or temperature that was applied to the FBG sensor because the ultrasound detection was not sensitive to the Bragg wavelength of the FBG sensor. PMID:22163995

  4. Full-Scale Prestress Loss Monitoring of Damaged RC Structures Using Distributed Optical Fiber Sensing Technology

    Directory of Open Access Journals (Sweden)

    Chunguang Lan

    2012-04-01

    Full Text Available For the safety of prestressed structures, prestress loss is a critical issue that will increase with structural damage, so it is necessary to investigate prestress loss of prestressed structures under different damage scenarios. Unfortunately, to date, no qualified techniques are available due to difficulty for sensors to survive in harsh construction environments of long service life and large span. In this paper, a novel smart steel strand based on the Brillouin optical time domain analysis (BOTDA sensing technique was designed and manufactured, and then series of tests were used to characterize properties of the smart steel strands. Based on prestress loss principle analysis of damaged structures, laboratory tests of two similar beams with different damages were used to verify the concept of full-scale prestress loss monitoring of damaged reinforced concrete (RC beams by using the smart steel strands. The prestress losses obtained from the Brillouin sensors are compared with that from conventional sensors, which provided the evolution law of prestress losses of damaged RC beams. The monitoring results from the proposed smart strand can reveal both spatial distribution and time history of prestress losses of damaged RC beams.

  5. Full-scale prestress loss monitoring of damaged RC structures using distributed optical fiber sensing technology.

    Science.gov (United States)

    Lan, Chunguang; Zhou, Zhi; Ou, Jinping

    2012-01-01

    For the safety of prestressed structures, prestress loss is a critical issue that will increase with structural damage, so it is necessary to investigate prestress loss of prestressed structures under different damage scenarios. Unfortunately, to date, no qualified techniques are available due to difficulty for sensors to survive in harsh construction environments of long service life and large span. In this paper, a novel smart steel strand based on the Brillouin optical time domain analysis (BOTDA) sensing technique was designed and manufactured, and then series of tests were used to characterize properties of the smart steel strands. Based on prestress loss principle analysis of damaged structures, laboratory tests of two similar beams with different damages were used to verify the concept of full-scale prestress loss monitoring of damaged reinforced concrete (RC) beams by using the smart steel strands. The prestress losses obtained from the Brillouin sensors are compared with that from conventional sensors, which provided the evolution law of prestress losses of damaged RC beams. The monitoring results from the proposed smart strand can reveal both spatial distribution and time history of prestress losses of damaged RC beams. PMID:22778590

  6. Rayleigh fiber optics gyroscope

    OpenAIRE

    Kung, A; Budin, J.; Thévenaz, Luc; Robert, P. A.

    1997-01-01

    A novel kind of fiber-optic gyroscope based on Rayleigh backscattering in a fiber-ring resonator is presented in this letter. Information on the rotation rate is obtained from the composed response of the fiber ring to an optical time-domain reflectometry (OTDR) instrument. The developed model based on the coherence properties of the Rayleigh scattering yields a polarization-insensitive and low-cost gyroscope

  7. An Efficient Wavelength variation approach for Bend Sensing in Single mode- Multimode-Single mode Optical Fiber Sensors

    Directory of Open Access Journals (Sweden)

    Abdul Samee Khan

    2012-09-01

    Full Text Available Several aspects of the SMS edge filters have beeninvestigated, including the effect of bending the SMS fibercores due to fabrication tolerances, polarizationdependence, and temperature dependence. These aspectscan impair the performance of a wavelength measurementsystem. There are several approaches which have beenproposed and demonstrated to achieve high resolution andaccuracy of wavelength measurement. Bending effects dueto the splicing process on the spectral characteristics ofSMS fibre structure-based edge filters are investigatedexperimentally with the help of MATLAB. A limit for thetolerable of the cores of an SMS fibre structure-based edgefilter is proposed, beyond which the edge filter’s spectralperformance degrades unacceptably. We use Wavelengthvariation approach by which we reduce the power loss dueto the bending in the optical fiber. Due to the power lossthe power transmission is increases and efficiency reduces.So by wavelength variation approach we developed anefficient spectrometer capable of performing a wide varietyof coherent multidimensional measurements at opticalwavelengths. In this approach we fixed the power andperform variation in the wavelength to sense the bendingaccurately. The two major components of the largelyautomated device are a spatial beam shaper which controlsthe beam geometry and a spatiotemporal pulse shaperwhich controls the temporal waveform of the femtosecondpulse in each beam. By which we sense the distortion toreduce the power transmission. We apply our algorithm forperforming several comparison considerations whichshows the performance of our algorithm which is better incomparison to the previous work

  8. Hydrogen Optical Fiber Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Lieberman, Robert A.; Beshay, Manal; Cordero, Steven R.

    2008-07-28

    Optically-based hydrogen sensors promise to deliver an added level of safety as hydrogen and fuel cell technologies enter the mainstream. More importantly, they offer reduced power consumption and lower cost, which are desirable for mass production applications such as automobiles and consumer appliances. This program addressed two of the major challenges previously identified in porous optrode-based optical hydrogen sensors: sensitivity to moisture (ambient humidity), and interference from the oxygen in air. Polymer coatings to inhibit moisture and oxygen were developed in conjunction with newer and novel hydrogen sensing chemistries. The results showed that it is possible to achieve sensitive hydrogen detection and rapid response with minimal interference from oxygen and humidity. As a result of this work, a new and more exciting avenue of investigation was developed: the elimination of the porous optrode and deposition of the sensor chemistry directly into the polymer film. Initial results have been promising, and open up a wider range of potential applications from extended optical fiber sensing networks, to simple plastic "stickers" for use around the home and office.

  9. Single- and few-moded lithium aluminosilicate optical fiber for athermal Brillouin strain sensing.

    Science.gov (United States)

    Dragic, P D; Ryan, C; Kucera, C J; Cavillon, M; Tuggle, M; Jones, M; Hawkins, T W; Yablon, A D; Stolen, R; Ballato, J

    2015-11-01

    Results are presented toward realizing a true single-mode fiber whose Brillouin frequency shift is independent of temperature, while its dependence on strain is comparable to conventional high-silica-content single-mode fibers. Demonstrated here is a fiber with a negative thermal sensitivity d?/dT of -0.26??MHz/K and a strain sensitivity of +406??MHz/%. The suppression of the Brillouin thermal response is enabled by the large thermal expansion coefficient of the group I oxide-containing silica glass network. PMID:26512511

  10. Specialty fiber optic applications for harsh and high radiation environments

    Science.gov (United States)

    Risch, Brian G.

    2015-05-01

    Since the first commercial introduction in the 1980s, optical fiber technology has undergone an almost exponential growth. Currently over 2 billion fiber kilometers are deployed globally with 2014 global optical fiber production exceeding 300 million fiber kilometers. 1 Along with the staggering growth in optical fiber production and deployment, an increase in optical fiber technologies and applications has also followed. Although the main use of optical fibers by far has been for traditional data transmission and communications, numerous new applications are introduced each year. Initially the practical application of optical fibers was limited by cost and sensitivity of the optical fibers to stress, radiation, and other environmental factors. Tremendous advances have taken place in optical fiber design and materials allowing optical fibers to be deployed in increasingly harsh environments with exposure to increased mechanical and environmental stresses while maintaining high reliability. With the increased reliability, lower cost, and greatly expanded range of optical fiber types now available, new optical fiber deployments in harsh and high radiation environments is seeing a tremendous increase for data, communications, and sensing applications. An overview of key optical fiber applications in data, communications, and sensing for harsh environments in industrial, energy exploration, energy generation, energy transmission, and high radiation applications will be presented. Specific recent advances in new radiation resistant optical fiber types, other specialty optical fibers, optical fiber coatings, and optical fiber cable materials will be discussed to illustrate long term reliability for deployment of optical fibers in harsh and high radiation environments.

  11. Indium-Tin-Oxide coated optical fibers for temperature-viscosity sensing applications in synthetic lubricant oils

    Science.gov (United States)

    Sanchez, P.; Mendizabal, D.; R. Zamarreño, C.; Arregui, F. J.; Matias, I. R.

    2015-09-01

    In this work, is presented the fabrication and characterization of optical fiber refractometer based on lossy mode resonances (LMR). Indium-Tin-Oxide (ITO) thin films deposited on optical fibers are used as the LMR supporting coatings. These resonances shift to the red as a function of the external refractive index. The refractometer has been used to characterize temperature variations related to the viscosity of synthetic industrial gear lubricant.

  12. Soil-embedded optical fiber sensing cable interrogated by Brillouin optical time-domain reflectometry (B-OTDR) and optical frequency-domain reflectometry (OFDR) for embedded cavity detection and sinkhole warning system

    International Nuclear Information System (INIS)

    A soil-embedded optical fiber sensing cable is evaluated for an embedded cavity detection and sinkhole warning system in railway tunnels. Tests were performed on a decametric structure equipped with an embedded 110 m long fiber optic cable. Both Brillouin optical time-domain reflectometry (B-OTDR) and optical frequency-domain reflectometry (OFDR) sensing techniques were used for cable interrogation, yielding results that were in good qualitative agreement with finite-element calculations. Theoretical and experimental comparison enabled physical interpretation of the influence of ground properties, and the analysis of embedded cavity size and position. A 5 mm embedded cavity located 2 m away from the sensing cable was detected. The commercially available sensing cable remained intact after soil collapse. Specificities of each technique are analyzed in view of the application requirements. For tunnel monitoring, the OFDR technique was determined to be more viable than the B-OTDR due to higher spatial resolution, resulting in better detection and size determination of the embedded cavities. Conclusions of this investigation gave outlines for future field use of distributed strain-sensing methods under railways and more precisely enabled designing a warning system suited to the Ebersviller tunnel specificities

  13. Sub-cm Resolution Distributed Fiber Optic Hydrogen Sensing with Nano-Engineered TiO2

    OpenAIRE

    Poole, Zsolt; Ohodnicki, Paul; Yan, Aidong; Lin, Yuankun; Chen, Kevin

    2015-01-01

    The 3D nano-structuring on the 2) to be reduced and matched with the cladding of optical fiber(n~1.46) for low-loss integration. A high temperature capable hydrogen sensor composed of D-shaped optical fiber with palladium nanoparticles infused nanoporous (~5nm) TiO2 film is demonstrated. The behavior of the developed sensor was characterized by examining the wavelength of an incorporated Fiber Bragg Grating and by observing the transmission losses at temperatures up to 700C....

  14. Woven fiber optics.

    Science.gov (United States)

    Schmidt, A C; Courtney-Pratt, J S; Ross, E A

    1975-02-01

    In this paper we describe how the art of weaving can be applied to fiber optics in order to produce precisely controlled reproducible image guides and image dissectors. As examples of the types of device for which woven fiber optics are applicable, we describe a 3:1 interleaver for use with a cathode-ray tube to produce color images, and a high speed alpha numeric output device. The techniques of weaving fiber optics are discussed in sufficient detail in order to allow for further work. Although, in principle, one might be able to weave glass optical fibers, all the work described here made use of plastic optical fibers 0.25 mm in diameter. PMID:20134880

  15. Fiber optic hydrophone

    Science.gov (United States)

    Kuzmenko, Paul J. (Livermore, CA); Davis, Donald T. (Livermore, CA)

    1994-01-01

    A miniature fiber optic hydrophone based on the principles of a Fabry-Perot interferometer. The hydrophone, in one embodiment, includes a body having a shaped flexible bladder at one end which defines a volume containing air or suitable gas, and including a membrane disposed adjacent a vent. An optic fiber extends into the body with one end terminating in spaced relation to the membrane. Acoustic waves in the water that impinge on the bladder cause the pressure of the volume therein to vary causing the membrane to deflect and modulate the reflectivity of the Fabry-Perot cavity formed by the membrane surface and the cleaved end of the optical fiber disposed adjacent to the membrane. When the light is transmitted down the optical fiber, the reflected signal is amplitude modulated by the incident acoustic wave. Another embodiment utilizes a fluid filled volume within which the fiber optic extends.

  16. Optical fiber Sagnac interferometer for sensing scalar directional refraction: Application to magnetochiral birefringence

    OpenAIRE

    Loas, Goulc'Hen; Alouini, Mehdi; Vallet, Marc

    2014-01-01

    We present a setup dedicated to the measurement of the small scalar directional anisotropies associated to the magnetochiral interaction. The apparatus, based on a polarization-independent fiber Sagnac interferometer, is optimized to be insensitive to circular anisotropies and to residual absorption. It can thus characterize samples of biological interests, for which the two enantiomers are not available and/or which present poor transmission. The signal-to-noise ratio is shown to be limited ...

  17. Multi optical path generator for fiber optic strain sensors multiplexing

    Science.gov (United States)

    Luo, Hao; Yuan, Yonggui; Yuan, Libo

    2015-07-01

    A multi optical path generator based on a tunable long Fabry-Perot optical fiber cavity is proposed and demonstrated. It would be used in an optical fiber sensing system which could multiplex a number of fiber sensors with different gauge lengths. Using this optical path generator, we can get a sequence of light beams with different optical paths, which will be coupled to the fiber sensor array in the sensing system. The multi optical path lengths generated by the device are analyzed and discussed. And the relative intensity of the corresponding light beam is calculated. The multiplexing capability caused by the optical path generator is discussed and the experimental results are confirmed this. The system can be used in strain or deformation sensing for smart structure health monitoring.

  18. One step method to attach gold nanoparticles onto the surface of an optical fiber used for refractive index sensing

    Science.gov (United States)

    García, J. A.; Monzón-Hernández, D.; Manríquez, J.; Bustos, E.

    2016-01-01

    Localized surface plasmon resonance (LSPR) has recently emerged as an efficient and powerful tool for bio-photonic applications due to its high sensitivity to refractive index changes. One technique to excite LSP is by the interaction of the evanescent wave of the light guided by an optical fiber with metallic nanoparticles deposited over the surface of the fiber. This paper proposes a novel, simple, and fast method to attach gold nanoparticles to the optical fiber surface, which can be used to construct highly sensitive refractive index sensors based on localized surface plasmon resonance. A hetero-core structured fiber, composed by a small section of single-mode fiber inserted in a multimode fiber, was coated with nanoparticles using the method proposed here. A sensor sensitivity and resolution of 765 nm/RIU and ?1 × 10-4 RIU, respectively, were estimated over a refractive index range of 1.333-1.365. This coating method is appealing to construct optical fiber refractive index sensors since it is very simple and low cost.

  19. Fiber optic spanner

    Science.gov (United States)

    Black, Bryan; Mohanty, Samarendra

    2011-10-01

    Rotation is a fundamental function in nano/biotechnology and is being useful in a host of applications such as pumping of fluid flow in microfluidic channels for transport of micro/nano samples. Further, controlled rotation of single cell or microscopic object is useful for tomographic imaging. Though conventional microscope objective based laser spanners (based on transfer of spin or orbital angular momentum) have been used in the past, they are limited by the short working distance of the microscope objective. Here, we demonstrate development of a fiber optic spanner for rotation of microscopic objects using single-mode fiber optics. Fiber-optic trapping and simultaneous rotation of pin-wheel structure around axis perpendicular to fiber-optic axis was achieved using the fiber optic spanner. By adjusting the laser beam power, rotation speed of the trapped object and thus the microfluidic flow could be controlled. Since this method does not require special optical or structural properties of the sample to be rotated, three-dimensional rotation of a spherical cell could also be controlled. Further, using the fiber optic spanner, array of red blood cells could be assembled and actuated to generate vortex motion. Fiber optical trapping and spinning will enable physical and spectroscopic analysis of microscopic objects in solution and also find potential applications in lab- on-a-chip devices.

  20. Chemical sensing with optical fibers and planar waveguides for biomedical applications

    Science.gov (United States)

    Verga Scheggi, Anna M.; Baldini, Francesco

    1994-02-01

    Main physical phenomena, exploited for the realization of optical chemical sensors, and different immobilization techniques for the realization of the optrode are reviewed and general considerations on the optoelectronic system are given. Many interesting examples of constructed optrodes are described.

  1. Development of special optical fibers for evanescent-wave chemical sensing.

    Czech Academy of Sciences Publication Activity Database

    Mat?jec, Vlastimil; Chomát, Miroslav; Hayer, Miloš; Kašík, Ivan; Berková, Daniela; Abdelmalek, F.; Jaffrezic-Renault, N.

    1999-01-01

    Ro?. 49, ?. 5 (1999), s. 883-888. ISSN 0011-4626. [Czech-Chinese Workshop on Advanced Materials for Optoelectronics - AMFO'98. Prague, 15.06.1998-17.06.1998] R&D Projects: GA ?R GA102/98/1358; GA ?R GA102/96/0939 Institutional research plan: CEZ:AV0Z2067918; Joint project No.4104 AS CR and CNRS France Keywords : optical sensors * optical fibres Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.328, year: 1999

  2. Novel silica surface charge density mediated control of the optical properties of embedded optically active materials and its application for fiber optic pH sensing at elevated temperatures

    Science.gov (United States)

    Wang, Congjun; Ohodnicki, Paul R.; Su, Xin; Keller, Murphy; Brown, Thomas D.; Baltrus, John P.

    2015-01-01

    Silica and silica incorporated nanocomposite materials have been extensively studied for a wide range of applications. Here we demonstrate an intriguing optical effect of silica that, depending on the solution pH, amplifies or attenuates the optical absorption of a variety of embedded optically active materials with very distinct properties, such as plasmonic Au nanoparticles, non-plasmonic Pt nanoparticles, and the organic dye rhodamine B (not a pH indicator), coated on an optical fiber. Interestingly, the observed optical response to varying pH appears to follow the surface charge density of the silica matrix for all the three different optically active materials. To the best of our knowledge, this optical effect has not been previously reported and it appears universal in that it is likely that any optically active material can be incorporated into the silica matrix to respond to solution pH or surface charge density variations. A direct application of this effect is for optical pH sensing which has very attractive features that can enable minimally invasive, remote, real time and continuous distributed pH monitoring. Particularly, as demonstrated here, using highly stable metal nanoparticles embedded in an inorganic silica matrix can significantly improve the capability of pH sensing in extremely harsh environments which is of increasing importance for applications in unconventional oil and gas resource recovery, carbon sequestration, water quality monitoring, etc. Our approach opens a pathway towards possible future development of robust optical pH sensors for the most demanding environmental conditions. The newly discovered optical effect of silica also offers the potential for control of the optical properties of optically active materials for a range of other potential applications such as electrochromic devices.Silica and silica incorporated nanocomposite materials have been extensively studied for a wide range of applications. Here we demonstrate an intriguing optical effect of silica that, depending on the solution pH, amplifies or attenuates the optical absorption of a variety of embedded optically active materials with very distinct properties, such as plasmonic Au nanoparticles, non-plasmonic Pt nanoparticles, and the organic dye rhodamine B (not a pH indicator), coated on an optical fiber. Interestingly, the observed optical response to varying pH appears to follow the surface charge density of the silica matrix for all the three different optically active materials. To the best of our knowledge, this optical effect has not been previously reported and it appears universal in that it is likely that any optically active material can be incorporated into the silica matrix to respond to solution pH or surface charge density variations. A direct application of this effect is for optical pH sensing which has very attractive features that can enable minimally invasive, remote, real time and continuous distributed pH monitoring. Particularly, as demonstrated here, using highly stable metal nanoparticles embedded in an inorganic silica matrix can significantly improve the capability of pH sensing in extremely harsh environments which is of increasing importance for applications in unconventional oil and gas resource recovery, carbon sequestration, water quality monitoring, etc. Our approach opens a pathway towards possible future development of robust optical pH sensors for the most demanding environmental conditions. The newly discovered optical effect of silica also offers the potential for control of the optical properties of optically active materials for a range of other potential applications such as electrochromic devices. Electronic supplementary information (ESI) available: Schematic of the experimental setup, SEM images of the optical fiber sensors, XPS spectra of the sensor materials, as well as additional sensing results from control experiments. See DOI: 10.1039/c4nr06232a

  3. High-power fiber laser sources for remote sensing

    Science.gov (United States)

    Di Teodoro, Fabio

    2013-09-01

    Pulse fiber lasers constitute a promising optical transmitter technology for remote sensing applications characterized by tight size, power consumption, and ruggedness constraints. In this paper, we review laser architecture and component solutions that support power scaling of efficient fiber-based sources towards long-range operation consistent with imaging and/or chemical sensing from space-based platforms.

  4. Fiber optics standard dictionary

    CERN Document Server

    Weik, Martin H

    1997-01-01

    Fiber Optics Vocabulary Development In 1979, the National Communications System published Technical InfonnationBulle­ tin TB 79-1, Vocabulary for Fiber Optics and Lightwave Communications, written by this author. Based on a draft prepared by this author, the National Communications System published Federal Standard FED-STD-1037, Glossary of Telecommunications Terms, in 1980 with no fiber optics tenns. In 1981, the first edition of this dictionary was published under the title Fiber Optics and Lightwave Communications Standard Dictionary. In 1982, the then National Bureau of Standards, now the National Institute of Standards and Technology, published NBS Handbook 140, Optical Waveguide Communications Glossary, which was also published by the General Services Admin­ istration as PB82-166257 under the same title. Also in 1982, Dynamic Systems, Inc. , Fiberoptic Sensor Technology Handbook, co-authored and edited by published the this author, with an extensive Fiberoptic Sensors Glossary. In 1989, the handbook w...

  5. Optical remote sensing

    CERN Document Server

    Prasad, Saurabh; Chanussot, Jocelyn

    2011-01-01

    Optical remote sensing relies on exploiting multispectral and hyper spectral imagery possessing high spatial and spectral resolutions respectively. These modalities, although useful for most remote sensing tasks, often present challenges that must be addressed for their effective exploitation. This book presents current state-of-the-art algorithms that address the following key challenges encountered in representation and analysis of such optical remotely sensed data: challenges in pre-processing images, storing and representing high dimensional data, fusing different sensor modalities, patter

  6. Fiber optic sensing of magnetic fields utilizing femtosecond laser sculpted microslots and long period gratings coated with Terfenol-D

    Science.gov (United States)

    Lee, Graham C. B.; Allsop, Tom; Wang, Changle; Neal, Ron; Culverhouse, Philip; Webb, David J.

    2015-09-01

    Fiber optic sensors are fabricated for detecting static magnetic fields. The sensors consist of a UV inscribed long period grating with two 50 micron long microslots. The microslots are fabricated using the femtosecond laser based inscribe and etch technique. The microslots and the fiber surface are coated with a magnetostrictive material Terfenol-D. A spectral sensitivity of 1.15 pm/mT was measured in transmission with a working resolution of ±0.2 mT for a static magnetic field strength below 10 mT. These devices also present a different response when the spatial orientation of the fiber was adjusted relative to the magnetic field lines.

  7. Highly sensitive and simple method for refractive index sensing of liquids in microstructured optical fibers using four-wave mixing

    DEFF Research Database (Denmark)

    Frosz, Michael Henoch; Stefani, Alessio; Bang, Ole

    2011-01-01

    We present both experimental measurements and simulations for a simple fiber-optical liquid refractive index sensor, made using only commercially available components and without advanced postprocessing of the fiber. Despite the simplicity, we obtain the highest sensitivity experimentally...... demonstrated to date for aqueous solutions (refractive index around 1.33), which is relevant for extensions to biosensing. The sensor is based on measuring the spectral shift of peaks arising from four-wave mixing (FWM), when filling the holes of a microstructured fiber with different liquid samples and...

  8. Optical fiber spectrophotometer

    International Nuclear Information System (INIS)

    A method called 'Two Arm's Photo out and Electricity Send-back' is introduced. UV-365 UV/VIS/NIR spectrophotometer has been reequipped by this way with 5 meters long optical fiber. Another method called 'One Arm's Photo out and Photo Send-back' is also introduced. ?19 UV/VIS/NIR spectrophotometer has been reequipped by this way with 10 meters long optical fiber. Optical fiber spectrophotometer can work as its main set. So it is particularly applicable to radio activity work

  9. Optical fiber Sagnac interferometer for sensing scalar directional refraction: application to magnetochiral birefringence

    CERN Document Server

    Loas, Goulc'hen; Vallet, Marc

    2014-01-01

    We present a set-up dedicated to the measurement of the small scalar directional anisotropies associated to the magnetochiral interaction. The apparatus, based on a polarization-independent fiber Sagnac interferometer, is optimized to be insensitive to circular anisotropies and to residual absorption. It can thus characterize samples of biological interests, for which the two enantiomers are not available and/or which present poor transmission. The signal-to-noise ratio is shown to be limited only by the source intensity noise, leading to a detection limit of Df = 500 nrad.Hz-1/2. It yields a limit on the magnetochiral index nMC < 4 10-13 T-1 at 1550 nm for the organic molecules tested.

  10. Photoelastic Fiber-Optic Accelerometers.

    Science.gov (United States)

    Su, Wei

    This dissertation introduces a completely new class of fiber-optic accelerometers based on the principles of photoelasticity. Two different types of accelerometers are designed and developed. The first is a general purpose accelerometer which employs a sensing element made from an optically sensitive photoelastic plastic; the unit is designed with a relatively low natural frequency and a high sensitivity. The second is a shock accelerometer which employs a glass GRIN lens as its sensing element; the unit is designed with a relatively high frequency and a wide measurement range. In both cases, a low-cost LED is employed as an incoherent light source; multimode optical fibers having a hard plastic cladding are used to transmit signals between the acceleration transducer and the conditioning electronics. The dissertation includes a brief introduction to accelerometer measurement in which current applications and associated problems are presented; detailed descriptions of the operating principles and design criteria considered when building an accelerometer; prior related research; discussions involving photoelastic fiber-optic transducers; a comprehensive analysis of sensing elements; the designs for the overall measurement systems; and, the results obtained by testing prototypes produced from the final designs. The qualitative and quantitative analyses contained herein represent a unique blend of mechanics, physics and electro-optics. A number of new discoveries are reported especially in conjunction with the analysis of the GRIN lens. Several new definitions are introduced, some of which make it possible to compare the performance of the photoelastic fiber-optic accelerometers to that of their more conventional counterparts. The test results show that both accelerometers meet their design requirements and their performance is comparable to some of the best accelerometers commercially available.

  11. Optical Waveguide Sensing and Imaging

    CERN Document Server

    Bock, Wojtek J; Tanev, Stoyan

    2008-01-01

    The book explores various aspects of existing and emerging fiber and waveguide optics sensing and imaging technologies including recent advances in nanobiophotonics. The focus is both on fundamental and applied research as well as on applications in civil engineering, biomedical sciences, environment, security and defence. The main goal of the multi-disciplinarry team of Editors was to provide an useful reference of state-of-the-art overviews covering a variety of complementary topics on the interface of engineering and biomedical sciences.

  12. Fiber optic data transmission

    Science.gov (United States)

    Shreve, Steven T.

    1987-01-01

    The Ohio University Avionics Engineering Center is currently developing a fiber optic data bus transmission and reception system that could eventually replace copper cable connections in airplanes. The original form of the system will transmit information from an encoder to a transponder via a fiber optic cable. An altimeter and an altitude display are connected to a fiber optic transmitter by copper cable. The transmitter converts the altimetry data from nine bit parallel to serial form and send these data through a fiber optic cable to a receiver. The receiver converts the data using a cable similar to that used between the altimeter and display. The transmitting and receiving ends also include a display readout. After completion and ground testing of the data bus, the system will be tested in an airborne environment.

  13. Fiber optic hydrogen sensor

    Science.gov (United States)

    Buchanan, Bruce R. (1985 Willis, Batesburg, SC 29006); Prather, William S. (2419 Dickey Rd., Augusta, GA 30906)

    1992-01-01

    An apparatus and method for detecting a chemical substance by exposing an optic fiber having a core and a cladding to the chemical substance so that the chemical substance can be adsorbed onto the surface of the cladding. The optic fiber is coiled inside a container having a pair of valves for controlling the entrance and exit of the substance. Light from a light source is received by one end of the optic fiber, preferably external to the container, and carried by the core of the fiber. Adsorbed substance changes the transmissivity of the fiber as measured by a spectrophotometer at the other end, also preferably external to the container. Hydrogen is detected by the absorption of infrared light carried by an optic fiber with a silica cladding. Since the adsorption is reversible, a sensor according to the present invention can be used repeatedly. Multiple positions in a process system can be monitored using a single container that can be connected to each location to be monitored so that a sample can be obtained for measurement, or, alternatively, containers can be placed near each position and the optic fibers carrying the partially-absorbed light can be multiplexed for rapid sequential reading by a single spectrophotometer.

  14. Assessment of a fiber-optic distributed-temperature-sensing system to monitor the thermal dynamics of vegetated roof

    Science.gov (United States)

    Cousiño, J. A.; Hausner, M. B.; Victorero, F.; Bonilla, C.; Gironas, J. A.; Vera, S.; Bustamante, W.; Rojas, V.; Pasten, P.; Suarez, F. I.

    2014-12-01

    Vegetated (green) roofs include a growing media and vegetation layer, and offer a range of benefits such as the reduction of: the heat island effect, rooftop runoff peak flows, roof surface temperatures, energy used for cooling or heating buildings, and noise levels inside infrastructures. Vegetated roofs also offer aesthetic benefits and increase the biodiversity of the urban environment, and are increasingly used in sustainable urban development. Understanding the thermal dynamics of vegetated roofs will make it possible to improve their design and to better assess their impacts on energy efficiency. Here, we evaluate the first vertical high-resolution distributed-temperature-sensing (DTS) system installed in a vegetated roof. This system allows a continuous measurement of the thermal profile within a vegetated roof - going from the interior, upward through the drainage layers and soil substrate of the vegetated roof and ending in the air above the vegetation. Temperatures can be observed as frequently as every 30 s at a spatial resolution on the order of centimeters. This DTS system was installed in the "Laboratory of Vegetal Infrastructure of Buildings" (LIVE - its acronym in Spanish), located in the San Joaquín Campus of the Pontifical Catholic University, Santiago, Chile. The laboratory features 18 experimental modules to investigate different configurations of the vegetated roof layers. The LIVE was designed with the installation of the optical fibers in mind, and the DTS system allows simultaneous monitoring of three or four modules of the LIVE. In this work, we describe the design of this DTS deployment, the calibration metrics obtained using the software provided by the manufacturers, and other calibration algorithms previously developed. We compare the results obtained using single- and double-ended measurements, highlighting strengths and weaknesses of DTS methods. Finally, we present the observations obtained from this biophysical environment highlighting the features that are harder to observe using more traditional methods to measure temperature.

  15. Nonlinear effects in optical fibers

    CERN Document Server

    Ferreira, Mario F

    2011-01-01

    Cutting-edge coverage of nonlinear phenomena occurring inside optical fibers Nonlinear fiber optics is a specialized part of fiber optics dealing with optical nonlinearities and their applications. As fiber-optic communication systems have become more advanced and complex, the nonlinear effects in optical fibers have increased in importance, as they adversely affect system performance. Paradoxically, the same nonlinear phenomena also offer the promise of addressing the bandwidth bottleneck for signal processing for future ultra-high speed optical networks. Nonlinear Effects in Optical Fiber

  16. A comparison of thermal infrared to fiber-optic distributed temperature sensing for evaluation of groundwater discharge to surface water

    Science.gov (United States)

    Hare, Danielle K.; Briggs, Martin A.; Rosenberry, Donald O.; Boutt, David F.; Lane, John W.

    2015-11-01

    Groundwater has a predictable thermal signature that can be used to locate discrete zones of discharge to surface water. As climate warms, surface water with strong groundwater influence will provide habitat stability and refuge for thermally stressed aquatic species, and is therefore critical to locate and protect. Alternatively, these discrete seepage locations may serve as potential point sources of contaminants from polluted aquifers. This study compares two increasingly common heat tracing methods to locate discrete groundwater discharge: direct-contact measurements made with fiber-optic distributed temperature sensing (FO-DTS) and remote sensing measurements collected with thermal infrared (TIR) cameras. FO-DTS is used to make high spatial resolution (typically m) thermal measurements through time within the water column using temperature-sensitive cables. The spatial-temporal data can be analyzed with statistical measures to reveal zones of groundwater influence, however, the personnel requirements, time to install, and time to georeference the cables can be burdensome, and the control units need constant calibration. In contrast, TIR data collection, either from handheld, airborne, or satellite platforms, can quickly capture point-in-time evaluations of groundwater seepage zones across large scales. However the remote nature of TIR measurements means they can be adversely influenced by a number of environmental and physical factors, and the measurements are limited to the surface "skin" temperature of water features. We present case studies from a range of lentic to lotic aquatic systems to identify capabilities and limitations of both technologies and highlight situations in which one or the other might be a better instrument choice for locating groundwater discharge. FO-DTS performs well in all systems across seasons, but data collection was limited spatially by practical considerations of cable installation. TIR is found to consistently locate groundwater seepage zones above and along the streambank, but submerged seepage zones are only well identified in shallow systems (e.g. <0.5 m depth) with moderate flow. Winter data collection, when groundwater is relatively warm and buoyant, increases the water surface expression of discharge zones in shallow systems.

  17. In-situ temperature measurement of the McMurdo Ice Shelf and ice shelf cavity using fiber-optic distributed temperature sensing

    Science.gov (United States)

    Kobs, S.; Tyler, S. W.; Holland, D. M.; Zagorodnov, V.; Stern, A. A.

    2013-12-01

    Ocean-ice interactions in ice shelf cavities have great potential to affect ice shelf mass balance and stability. In-situ temperature of the ice shelf and ocean water column at Windless Bight, Antarctica, was remotely monitored using fiber-optic distributed temperature sensing (DTS). Fiber-optic cables were installed in two boreholes completed using a combination of electromechanical and hot point drilling. Between November 2011 and January 2013 a set of moorings, comprising of fiber-optic cables for distributed temperature sensing, an independent thermistor string and pressure-temperature transducers were monitored. Data presented summarizes the field deployment of the system between November 2011 and January 2013. Heat serves as natural tracer in environmental systems and is useful for identifying fluxes across boundaries. The heat flux near the ice-ocean interface is estimated from the temperature gradient in the lower ice shelf. Variation in the ice shelf temperature near the ice-ocean interface can be seen. Finally, these new data show the intrusion of warm water under the ice shelf previously observed in 2012.

  18. Compact Fiber Optic Strain Sensors (cFOSS) Element

    Data.gov (United States)

    National Aeronautics and Space Administration — Armstrong researchers are reducing the Fiber Optic Sensing Sysme (FOSS) technology’s size, power requirement, weight, and cost to effectively extend...

  19. Silicon fiber optic sensors

    Science.gov (United States)

    Pocha, Michael D. (Livermore, CA); Swierkowski, Steve P. (Livermore, CA); Wood, Billy E. (Livermore, CA)

    2007-10-02

    A Fabry-Perot cavity is formed by a partially or wholly reflective surface on the free end of an integrated elongate channel or an integrated bounding wall of a chip of a wafer and a partially reflective surface on the end of the optical fiber. Such a constructed device can be utilized to detect one or more physical parameters, such as, for example, strain, through the optical fiber using an optical detection system to provide measuring accuracies of less than aboutb0.1%.

  20. FIBER OPTIC LIGHTING SYSTEMS

    Directory of Open Access Journals (Sweden)

    Munir BATUR

    2013-01-01

    Full Text Available Recently there have been many important and valuable developments in the communication industry. The huge increase in the sound, data and visual communications has caused a parallel increase in the demand for systems with wider capacity, higher speed and higher quality. Communication systems that use light to transfer data are immensely increased. There have recently many systems in which glass or plastic fiber cables were developed for light wave to be transmitted from a source to a target place. Fiber optic systems, are nowadays widely used in energy transmission control systems, medicine, industry and lighting. The basics of the system is, movement of light from one point to another point in fiber cable with reflections. Fiber optic lighting systems are quite secure than other lighting systems and have flexibility for realizing many different designs. This situation makes fiber optics an alternative for other lighting systems. Fiber optic lighting systems usage is increasing day-by-day in our life. In this article, these systems are discussed in detail.

  1. Chemical Sensing Using Fiber Cavity Ring-Down Spectroscopy

    OpenAIRE

    Hans-Peter Loock; Barnes, Jack A.; Adrienne H. Cheung; Jessica Litman; Helen Waechter

    2010-01-01

    Waveguide-based cavity ring-down spectroscopy (CRD) can be used for quantitative measurements of chemical concentrations in small amounts of liquid, in gases or in films. The change in ring-down time can be correlated to analyte concentration when using fiber optic sensing elements that change their attenuation in dependence of either sample absorption or refractive index. Two types of fiber cavities, i.e., fiber loops and fiber strands containing reflective elements, are distinguished. Both ...

  2. Fiber optic accelerometer

    Science.gov (United States)

    August, R. R.

    1981-01-01

    Low-cost, rugged lightweight accelerometer has been developed that converts mechanical motion into digitized optical outputs and is immune to electromagnetic and electrostatic interferences. Instrument can be placed in hostile environment, such as engine under test, and output led out through miscellany of electrical fields, high temperatures, etc., by optic fiber cables to benign environment of test panel. There, digitized optical signals can be converted to electrical signals for use in standard electrical equipment or used directly in optical devices, such as optical digital computer.

  3. Theoretical understanding of an alternating dielectric multilayer-based fiber optic SPR sensor and its application to gas sensing

    International Nuclear Information System (INIS)

    In the present work, a detailed theoretical analysis of a surface plasmon resonance (SPR)-based fiber optic sensor with an alternating dielectric multilayer system is carried out. The dielectric system consists of silica and titanium oxide layers. The effect of critical design parameters on the sensor's sensitivity and detection accuracy is studied. The results are explained in terms of appropriate physical phenomena, wherever required. Based on the analysis, a new design of a fiber optic SPR sensor for gas detection is proposed. The analysis of such a gas sensor is carried out for four metals separately for a clear understanding. The proposed gas sensor is able to provide reasonably high values of all the performance parameters simultaneously, as required for an efficient detection of gaseous media

  4. Fiber optic gas sensor

    Science.gov (United States)

    Chen, Peng (Inventor); Buric, Michael P. (Inventor); Swinehart, Philip R. (Inventor); Maklad, Mokhtar S. (Inventor)

    2010-01-01

    A gas sensor includes an in-fiber resonant wavelength device provided in a fiber core at a first location. The fiber propagates a sensing light and a power light. A layer of a material is attached to the fiber at the first location. The material is able to absorb the gas at a temperature dependent gas absorption rate. The power light is used to heat the material and increases the gas absorption rate, thereby increasing sensor performance, especially at low temperatures. Further, a method is described of flash heating the gas sensor to absorb more of the gas, allowing the sensor to cool, thereby locking in the gas content of the sensor material, and taking the difference between the starting and ending resonant wavelengths as an indication of the concentration of the gas in the ambient atmosphere.

  5. Dosimetry by optical fibers

    International Nuclear Information System (INIS)

    The Cea-Leti continues to perfect a prototype system to measure the radioactivity by optical fiber captor, developed in the frame of a collaboration with Cogema, whom one of the objectives is the operational dosimetry of extremities. This experimental device, developed by the Dein, uses a micro detector (diameter 200 ? m) with luminescence optically stimulated (O.S.L.) placed at the extremity of an off-centring optical fiber (40 m for the actual prototype). The detector material is a doped alkaline-earth sulfate, developed by the University of Montpellier. It shows the property to restore the image of absorbed dose under the shape of a visible luminescence when it is submitted to a stimulation in infrared radiation. In the prototype, this stimulation is given by a laser diode coupled to the fiber. Different detector materials have been tested, two have been kept for the prototype development: MgS and CaS. (N.C.)

  6. Optical fiber stripper positioning apparatus

    Science.gov (United States)

    Fyfe, Richard W. (Las Vegas, NV); Sanchez, Jr., Amadeo (Las Vegas, NV)

    1990-01-01

    An optical fiber positioning apparatus for an optical fiber stripping device is disclosed which is capable of providing precise axial alignment between an optical fiber to be stripped of its outer jacket and the cutting blades of a stripping device. The apparatus includes a first bore having a width approximately equal to the diameter of an unstripped optical fiber and a counter bore axially aligned with the first bore and dimensioned to precisely receive a portion of the stripping device in axial alignment with notched cutting blades within the stripping device to thereby axially align the notched cutting blades of the stripping device with the axis of the optical fiber to permit the notched cutting blades to sever the jacket on the optical fiber without damaging the cladding on the optical fiber. In a preferred embodiment, the apparatus further includes a fiber stop which permits determination of the length of jacket to be removed from the optical fiber.

  7. Optical fiber telecommunications IIIb

    CERN Document Server

    Koch, Thomas L

    2012-01-01

    Updated to include the latest information on light wave technology, Optical Fiber Telecommunication III, Volumes A & B are invaluable for scientists, students, and engineers in the modern telecommunications industry. This two-volume set includes the most current research available in optical fiber telecommunications, light wave technology, and photonics/optoelectronics. The authors cover important background concepts such as SONET, coding device technology, andWOM components as well as projecting the trends in telecommunications for the 21st century.Key Features* One of the hottest subjects of

  8. Fluoride glass fiber optics

    CERN Document Server

    Aggarwal, Ishwar D

    1991-01-01

    Fluoride Glass Fiber Optics reviews the fundamental aspects of fluoride glasses. This book is divided into nine chapters. Chapter 1 discusses the wide range of fluoride glasses with an emphasis on fluorozirconate-based compositions. The structure of simple fluoride systems, such as BaF2 binary glass is elaborated in Chapter 2. The third chapter covers the intrinsic transparency of fluoride glasses from the UV to the IR, with particular emphasis on the multiphonon edge and electronic edge. The next three chapters are devoted to ultra-low loss optical fibers, reviewing methods for purifying and

  9. Respiratory function monitoring using a real-time three-dimensional fiber-optic shaping sensing scheme based upon fiber Bragg gratings.

    Science.gov (United States)

    Allsop, Thomas; Bhamber, Ranjeet; Lloyd, Glynn; Miller, Martin R; Dixon, Andrew; Webb, David; Ania Castañón, Juan Diego; Bennion, Ian

    2012-11-01

    An array of in-line curvature sensors on a garment is used to monitor the thoracic and abdominal movements of a human during respiration. The results are used to obtain volumetric changes of the human torso in agreement with a spirometer used simultaneously at the mouth. The array of 40 in-line fiber Bragg gratings is used to produce 20 curvature sensors at different locations, each sensor consisting of two fiber Bragg gratings. The 20 curvature sensors and adjoining fiber are encapsulated into a low-temperature-cured synthetic silicone. The sensors are wavelength interrogated by a commercially available system from Moog Insensys, and the wavelength changes are calibrated to recover curvature. A three-dimensional algorithm is used to generate shape changes during respiration that allow the measurement of absolute volume changes at various sections of the torso. It is shown that the sensing scheme yields a volumetric error of 6%. Comparing the volume data obtained from the spirometer with the volume estimated with the synchronous data from the shape-sensing array yielded a correlation value 0.86 with a Pearson's correlation coefficient p<0.01. PMID:23117812

  10. Optical fiber communications

    CERN Document Server

    Keiser, Gerd

    2008-01-01

    The fourth edition of this popular text and reference book presents the fundamental principles for understanding and applying optical fiber technology to sophisticated modern telecommunication systems. Optical-fiber-based telecommunication networks have become a major information-transmission-system, with high capacity links encircling the globe in both terrestrial and undersea installations. Numerous passive and active optical devices within these links perform complex transmission and networking functions in the optical domain, such as signal amplification, restoration, routing, and switching. Along with the need to understand the functions of these devices comes the necessity to measure both component and network performance, and to model and stimulate the complex behavior of reliable high-capacity networks.

  11. A miniature fiber-optic sensor for high-resolution and high-speed temperature sensing in ocean environment

    Science.gov (United States)

    Liu, Guigen; Han, Ming; Hou, Weilin; Matt, Silvia; Goode, Wesley

    2015-05-01

    Temperature measurement is one of the key quantifies in ocean research. Temperature variations on small and large scales are key to air-sea interactions and climate change, and also regulate circulation patterns, and heat exchange. The influence from rapid temperature changes within microstructures are can have strong impacts to optical and acoustical sensor performance. In this paper, we present an optical fiber sensor for the high-resolution and high-speed temperature profiling. The developed sensor consists of a thin piece of silicon wafer which forms a Fabry-Pérot interferometer (FPI) on the end of fiber. Due to the unique properties of silicon, such as large thermal diffusivity, notable thermo-optic effects and thermal expansion coefficients of silicon, the proposed sensor exhibits excellent sensitivity and fast response to temperature variation. The small mass of the tiny probe also contributes to a fast response due to the large surface-tovolume ratio. The high reflective index at infrared wavelength range and surface flatness of silicon endow the FPI a spectrum with high visibilities, leading to a superior temperature resolution along with a new data processing method developed by us. Experimental results indicate that the fiber-optic temperature sensor can achieve a temperature resolution better than 0.001°C with a sampling frequency as high as 2 kHz. In addition, the miniature footprint of the senor provide high spatial resolutions. Using this high performance thermometer, excellent characterization of the realtime temperature profile within the flow of water turbulence has been realized.

  12. Reduced Gravity Zblan Optical Fiber

    Science.gov (United States)

    Tucker, Dennis S.; Workman, Gary L.; Smith, Guy A.

    2000-01-01

    Two optical fiber pullers have been designed for pulling ZBLAN optical fiber in reduced gravity. One fiber puller was designed, built and flown on board NASA's KC135 reduced gravity aircraft. A second fiber puller has been designed for use on board the International Space Station.

  13. Assessment of fiber optic pressure sensors

    International Nuclear Information System (INIS)

    This report presents the results of a six-month Phase 1 study to establish the state-of-the-art in fiber optic pressure sensing and describes the design and principle of operation of various fiber optic pressure sensors. This study involved a literature review, contact with experts in the field, an industrial survey, a site visit to a fiber optic sensor manufacturer, and laboratory testing of a fiber optic pressure sensor. The laboratory work involved both static and dynamic performance tests. In addition, current requirements for environmental and seismic qualification of sensors for nuclear power plants were reviewed to determine the extent of the qualification tests that fiber optic pressure sensors may have to meet before they can be used in nuclear power plants. This project has concluded that fiber optic pressure sensors are still in the research and development stage and only a few manufacturers exist in the US and abroad which supply suitable fiber optic pressure sensors for industrial applications. Presently, fiber optic pressure sensors are mostly used in special applications for which conventional sensors are not able to meet the requirements

  14. Assessment of fiber optic pressure sensors

    Energy Technology Data Exchange (ETDEWEB)

    Hashemian, H.M.; Black, C.L.; Farmer, J.P. [Analysis and Measurement Services Corp., Knoxville, TN (United States)

    1995-04-01

    This report presents the results of a six-month Phase 1 study to establish the state-of-the-art in fiber optic pressure sensing and describes the design and principle of operation of various fiber optic pressure sensors. This study involved a literature review, contact with experts in the field, an industrial survey, a site visit to a fiber optic sensor manufacturer, and laboratory testing of a fiber optic pressure sensor. The laboratory work involved both static and dynamic performance tests. In addition, current requirements for environmental and seismic qualification of sensors for nuclear power plants were reviewed to determine the extent of the qualification tests that fiber optic pressure sensors may have to meet before they can be used in nuclear power plants. This project has concluded that fiber optic pressure sensors are still in the research and development stage and only a few manufacturers exist in the US and abroad which supply suitable fiber optic pressure sensors for industrial applications. Presently, fiber optic pressure sensors are mostly used in special applications for which conventional sensors are not able to meet the requirements.

  15. Porous solgel fiber as a transducer for highly sensitive chemical sensing.

    Science.gov (United States)

    Tao, Shiquan; Winstead, Christopher B; Singh, Jagdish P; Jindal, Rajeev

    2002-08-15

    A novel solgel process for making porous silica fiber and doping the fiber core with sensing material is described. A CoCl(2) -doped solgel fiber was fabricated and was used to construct an active-core optical fiber moisture sensor. Test results show that the sensitivity of the active-core optical fiber sensor is much higher than that of an evanescent-wave-based optical fiber sensor. PMID:18026453

  16. Optical fiber-applied radiation detection system

    International Nuclear Information System (INIS)

    A technique to measure radiation by using plastic scintillation fibers doped radiation fluorescent (scintillator) to plastic optical fiber for a radiation sensor, was developed. The technique contains some superiority such as high flexibility due to using fibers, relatively easy large area due to detecting portion of whole of fibers, and no electromagnetic noise effect due to optical radiation detection and signal transmission. Measurable to wide range of and continuous radiation distribution along optical fiber cable at a testing portion using scintillation fiber and flight time method, the optical fiber-applied radiation sensing system can effectively monitor space radiation dose or apparatus operation condition monitoring. And, a portable type scintillation optical fiber body surface pollution monitor can measure pollution concentration of radioactive materials attached onto body surface by arranging scintillation fiber processed to a plate with small size and flexibility around a man to be tested. Here were described on outline and fundamental properties of various application products using these plastic scintillation fiber. (G.K.)

  17. Aerogel-clad optical fiber

    Science.gov (United States)

    Sprehn, Gregory A. (Livermore, CA); Hrubesh, Lawrence W. (Pleasanton, CA); Poco, John F. (Livermore, CA); Sandler, Pamela H. (San Marino, CA)

    1997-01-01

    An optical fiber is surrounded by an aerogel cladding. For a low density aerogel, the index of refraction of the aerogel is close to that of air, which provides a high numerical aperture to the optical fiber. Due to the high numerical aperture, the aerogel clad optical fiber has improved light collection efficiency.

  18. Fluoride Fibers For Remote Chemical Sensing

    Science.gov (United States)

    Saggese, Steven J.; Shahriari, Mahmoud R.; Sigel, George H.

    1988-07-01

    Fluoride glass optical waveguides (ZBLAN) were coupled to a Fourier Transform Infrared Analyzer (FTIR) to execute remote IR chemical sensing. These fibers were used passively for only signal transmission, and the sensing was accomplished by direct or evanescent absorption of the fundamental modes corresponding to the desired chemical species. Due to the poor chemical and physical durability of fluoride glass, a crystal optrode (ZnSe) was used for evanescent wave absorption to isolate the fibers from the sensing environment. Several different types of chemical mixtures were studied to show the flexibility and limitations of such a system: 1) methane gas concentration in nitrogen using the C-H absorption at 3.31 um, 2) alcohol concentration in water using the C-H absorption at 3.36 um, and 3) water concentration in 1,4 dioxane using the 0-H fundamental stretching mode at 2.9 um. The last mixture proved to be the most difficult to analyze due to the low transmission of the fluoride fiber system in the 2.9 um region.

  19. Quasi-distributed long-gauge fiber optic sensor system

    OpenAIRE

    Linec, Matjaž; Ðonlagi?, Denis

    2012-01-01

    This paper presents a quasi-distributed, long-gauge, sensor system for measurement optical path length variation. This system can be directly applied to long gauge strain and/or temperature sensing. The proposed sensor system is comprised of sensing fiber, which is divided into the sensor?s segments separated by semi reflective mirrors made out of standard optical connectors. Short duration radio-frequency modulated optical bursts are launched into the sensing fiber and phase differences amon...

  20. Nonlinear fiber optics

    CERN Document Server

    Agrawal, Govind

    2012-01-01

    Since the 4e appeared, a fast evolution of the field has occurred. The 5e of this classic work provides an up-to-date account of the nonlinear phenomena occurring inside optical fibers, the basis of all our telecommunications infastructure as well as being used in the medical field. Reflecting the big developments in research, this new edition includes major new content: slow light effects, which offers a reduction in noise and power consumption and more ordered network traffic-stimulated Brillouin scattering; vectorial treatment of highly nonlinear fibers; and a brand new chapter o

  1. Fiber optics: A brief introduction

    International Nuclear Information System (INIS)

    A basic introduction into the principles of fiber optics is presented. A review of both the underlying physical principles and the individual elements of typical fiber-optic systems are presented. The optical phenomenon of total internal reflection is reviewed. The basic construction of the optical fiber is presented. Both step-index and graded-index fiber designs are reviewed. Multimode and single-mode fiber constructions are considered and typical performance parameters given. Typical optical-fiber bandwidth and loss characteristics are compared to various common coaxial cables, waveguides, and air transmission. The constructions of optical-fiber cables are reviewed. Both loose-tube and tightly-buffered designs are considered. Several optical connection approaches are presented. Photographs of several representative optical connectors are included. Light Emitting Diode and Laser Diode emitters for fiber-optic applications are reviewed, and some advantages and shortcomings of each are considered. The phenomenon of modal noise is briefly explained. Both PIN and Avalanche photodetectors are reviewed and their performance parameters compared. Methods of data transmission over optical fiber are introduced. Principles of Wavelength, Frequency, and Time Division Multiplexing are briefly presented. The technology of fiber-optic sensors is briefly reviewed with basic principles introduced. The performance of a fiber-optic strain sensor is included as a practical example. 7 refs., 10 figs

  2. Dynamic fiber Bragg grating sensing method

    Science.gov (United States)

    Ho, Siu Chun Michael; Ren, Liang; Li, Hongnan; Song, Gangbing

    2016-02-01

    The measurement of high frequency vibrations is important in many scientific and engineering problems. This paper presents a novel, cost effective method using fiber optic fiber Bragg gratings (FBGs) for the measurement of high frequency vibrations. The method uses wavelength matched FBG sensors, with the first sensor acting as a transmission filter and the second sensor acting as the sensing portion. Energy fluctuations in the reflection spectrum of the second FBG due to wavelength mismatch between the sensors are captured by a photodiode. An in-depth analysis of the optical circuit is provided to predict the behavior of the method as well as identify ways to optimize the method. Simple demonstrations of the method were performed with the FBG sensing system installed on a piezoelectric transducer and on a wind turbine blade. Vibrations were measured with sampling frequencies up to 1 MHz for demonstrative purposes. The sensing method can be multiplexed for use with multiple sensors, and with care, can be retrofitted to work with FBG sensors already installed on a structure.

  3. Large-strain optical fiber sensing and real-time FEM updating of steel structures under the high temperature effect

    International Nuclear Information System (INIS)

    Steel buildings are subjected to fire hazards during or immediately after a major earthquake. Under combined gravity and thermal loads, they have non-uniformly distributed stiffness and strength, and thus collapse progressively with large deformation. In this study, large-strain optical fiber sensors for high temperature applications and a temperature-dependent finite element model updating method are proposed for accurate prediction of structural behavior in real time. The optical fiber sensors can measure strains up to 10% at approximately 700?°C. Their measurements are in good agreement with those from strain gauges up to 0.5%. In comparison with the experimental results, the proposed model updating method can reduce the predicted strain errors from over 75% to below 20% at 800?°C. The minimum number of sensors in a fire zone that can properly characterize the vertical temperature distribution of heated air due to the gravity effect should be included in the proposed model updating scheme to achieve a predetermined simulation accuracy. (paper)

  4. Development and testing of redundant optical fiber sensing systems with self-control, for underground nuclear waste disposal site monitoring. Vol. 1: Summary and evaluation. Final report

    International Nuclear Information System (INIS)

    Fiber optic sensors have been developed or further developed, for specific tasks of the research project reported, as for instance detecting and signalling changes of geophysical or geochemical parameters in underground waste storage sites which are of relevance to operating safety. Such changes include e.g. materials dislocations, extensions, temperatures, humidity, pH value and presence of gaseous carbon dioxide and hydrogen. The measuring principle chosen is the fiber Bragg Grating method, as a particularly versatile method easy to integrate into fiber optic networks. After development and successful lab-scale testing of all sensors, except for the gas sensors, field test systems have been made for underground applications and have been tested in situ in the experimental Konrad mine of DBE. Most of the problems discovered with these tests could be resolved within the given project period, so that finally field-test proven sensing systems are available for further activities. The report explains the system performance with a concrete example which shows inter alia beneficial aspects of the system with respect to on-site operation, and the potentials offered in establishing more direct connections between numerical safety analyses and measured results. (orig./CB)

  5. Introduction to optical fiber sensors

    International Nuclear Information System (INIS)

    Optical fiber sensors have many advantages over other types of sensors, for example: Low weight, immunity from EMI, electrical isolation, chemical passivity, and high sensitivity. In this seminar, a brief explanation of the optical fiber sensors, their use, and their advantages will be given. After, a description of the main optical fiber sensor components will be presented. Principles of some kinds of optical fiber sensors will be presented, and the principle of the fiber-optic rotation sensor and its realization will be discussed in some details, as well as its main applications. (author). 5 refs, 8 figs, 2 tabs

  6. Fiber optic hydrogen sensors: a review

    Science.gov (United States)

    Yang, Minghong; Dai, Jixiang

    2014-12-01

    Hydrogen is one of the next generation energies in the future, which shows promising applications in aerospace and chemical industries. Hydrogen leakage monitoring is very dangerous and important because of its low ignition energy, high combustion efficiency, and smallest molecule. This paper reviews the state-of-art development of the fiber optic hydrogen sensing technology. The main developing trends of fiber optic hydrogen sensors are based on two kinds of hydrogen sensitive materials, i.e. palladium-alloy thin films and Pt-doped WO3 coatings. In this review work, the advantages and disadvantages of these two kinds of sensing technologies will be evaluated.

  7. Advances on Optical Fiber Sensors

    OpenAIRE

    Luciano Mescia; Francesco Prudenzano

    2013-01-01

    In this review paper some recent advances on optical fiber sensors are reported. In particular, fiber Bragg grating (FBG), long period gratings (LPGs), evanescent field and hollow core optical fiber sensors are mentioned. Examples of recent optical fiber sensors for the measurement of strain, temperature, displacement, air flow, pressure, liquid-level, magnetic field, and the determination of methadone, hydrocarbons, ethanol, and sucrose are briefly described.

  8. Towards biochips using microstructured optical fiber sensors

    DEFF Research Database (Denmark)

    Rindorf, Lars Henning; Hoiby, Poul Erik; Jensen, Jesper Bo; Pedersen, Lars Hagsholm; Bang, Ole; Geschke, Oliver

    2006-01-01

    In this paper we present the first incorporation of a microstructured optical fiber (MOF) into biochip applications. A 16-mm-long piece of MOF is incorporated into an optic-fluidic coupler chip, which is fabricated in PMMA polymer using a CO2 laser. The developed chip configuration allows the...... continuous control of liquid flow through the MOF and simultaneous optical characterization. While integrated in the chip, the MOF is functionalized towards the capture of a specific single-stranded DNA string by immobilizing a sensing layer on the microstructured internal surfaces of the fiber. The sensing...... layer contains the DNA string complementary to the target DNA sequence and thus operates through the highly selective DNA hybridization process. Optical detection of the captured DNA was carried out using the evanescent-wave-sensing principle. Owing to the small size of the chip, the presented technique...

  9. In-Line Fiber Optic Interferometric Sensors in Single-Mode Fibers

    OpenAIRE

    De-Wen Duan; Min Liu; Di Wu; Tao Zhu

    2012-01-01

    In-line fiber optic interferometers have attracted intensive attention for their potential sensing applications in refractive index, temperature, pressure and strain measurement, etc. Typical in-line fiber-optic interferometers are of two types: Fabry-Perot interferometers and core-cladding-mode interferometers. It’s known that the in-line fiber optic interferometers based on single-mode fibers can exhibit compact structures, easy fabrication and low cost. In this paper, ...

  10. Optical fiber laser

    Energy Technology Data Exchange (ETDEWEB)

    Hakimi, F.; Po, H.; Snitzer, E.

    1987-07-14

    An optical fiber laser is described comprising: a gain cavity including a single mode optical fiber of given length having a core with a given index of refraction and a cladding surrounding the core and having an index of refraction lower than that of the core. The core comprises a host glass having incorporated a laser gain material with a fluorescence spectrum having at least one broadband region in which there is at least one peak emission line; filter means optically coupled to one end of the gain cavity and reflective to radiation emitted from the gain material over a predetermined wavelength interval about the peak emission line to provide feedback in the gain cavity; an etalon filter section butt coupled to the remaining end of the gain cavity optical fiber, the etalon filter section comprising a pair of filters spaced apart in parallel by a predetermined length of material transparent to any radiation emitted from the gain cavity. The predetermined length of the transparent material is such that the etalon filter section is no longer than the distance over which the wave train energy from the fiber core remains substantially planar so that the etalon filter section is inside the divergent region to enhance feedback in the gain cavity; and means for pumping energy into the gain cavity to raise the interval energy level such that only a small part of the ion population, corresponding to a predetermined bandwidth about the peak emission line, is raised above laser threshold. The laser emits radiation only over narrow lines over a narrow wavelength interval centered about the peak emission line.

  11. Online fiber optic spectrophotometry

    Energy Technology Data Exchange (ETDEWEB)

    Van Hare, D.R.; O' Rourke, P.E.; Prather, W.S.

    1988-01-01

    A fiber optic diode array process analyzer has been developed and installed in a radiochemical separations facility at the Savannah River Plant. The analyzer monitors the uranium and nitrate concentration of seven aqueous process streams in a uranium purification process. The analyzer remotely controls the sampling of each process stream and monitors the relative flow rate through each sampler. Spectrophotometric data from the analyzer is processed by multivariate data analysis to give both uranium and nitrate concentrations as well as an indication of the quality of the data. The analyzer system consists of a DuPont Instruments diode array process analyzer, xenon arc lamp, fiber-optic multiplexer, and IBM industrial AT computer. Fused silica optical fibers (600 micrometer core diameter) connect the analyzer to monitor up to ten locations in series. In addition to the seven process locations, the analyzer also monitors a reference optical fiber and an inline uranyl nitrate standard. Process stream samplers are controlled by Opto 22 hardware and electric solenoid valves interfaced to the analyzer computer through an RS-422 communication link. Absorption data from each location is fed into a Partial Least Squares (PLS) model of the uranyl nitrate system for conversion into uranium and nitrate concentrations. The model also outputs a residual variance which is a very sensitive indicator of interferences in the system and is used to verify the quality of the calculated results. Results from the analyzer computer are sent by another Opto 22 interface to a distributed control system which is used to run the uranium purification process. 8 refs., 22 figs., 1 tab.

  12. Fiber optic geophysical sensors

    Science.gov (United States)

    Homuth, Emil F. (Los Alamos, NM)

    1991-01-01

    A fiber optic geophysical sensor in which laser light is passed through a sensor interferometer in contact with a geophysical event, and a reference interferometer not in contact with the geophysical event but in the same general environment as the sensor interferometer. In one embodiment, a single tunable laser provides the laser light. In another embodiment, separate tunable lasers are used for the sensor and reference interferometers. The invention can find such uses as monitoring for earthquakes, and the weighing of objects.

  13. Photometric device using optical fibers

    International Nuclear Information System (INIS)

    Remote measurements in radioactive environment are now possible with optical fibers. Measurement instruments developed by CEA are constitued of: - an optical probe (5 mm to 1 meter optical path length), - a photometric measurement device, - optical fiber links. 'TELEPHOT' is a photometric device for industrial installations. It is uses interferentiel filters for 2 to 5 simultaneous wave lengths. 'CRUDMETER' measures the muddiness of water. It can be equipped with a high sensitivity cell of 50 cm optical path length tested up to 250 bars. Coupling a double beam spectrophotometer to a remote optical probe, up to 1 meter optical path length, is carried out by means of an optical device using optical fibers links, eventually several hundred meter long. For these equipments special step index large core fibers, 1 to 1.5 mm in diameter, have been developed as well connectors. For industrial control and research these instruments offer new prospect thanks to optical fibers use

  14. Optical fiber synaptic sensor

    Science.gov (United States)

    Pisarchik, A. N.; Jaimes-Reátegui, R.; Sevilla-Escoboza, R.; García-Lopez, J. H.; Kazantsev, V. B.

    2011-06-01

    Understanding neuron connections is a great challenge, which is needed to solve many important problems in neurobiology and neuroengineering for recreation of brain functions and efficient biorobotics. In particular, a design of an optical synapse capable to communicate with neuron spike sequences would be crucial to improve the functionality of neuromimmetic networks. In this work we propose an optical synaptic sensor based on an erbium-doped fiber laser driven by a FitzHung-Nagumo electronic neuron, to connect with another electronic neuron. Two possible optical synaptic configurations are analyzed for optoelectronic coupling between neurons: laser cavity loss modulation and pump laser modulation. The control parameters of the proposed optical synapse provide additional degrees of flexibility to the neuron connection traditionally controlled only by coupling strengths in artificial networks.

  15. A photoelastic fiber optic strain gage

    Science.gov (United States)

    Su, Wei; Gilbert, John A.; Katsunis, Constantine

    1992-01-01

    This paper reports on the development of a photoelastic fiber optic strain gage sensitive to transverse strain. The sensing element is made from an epoxy resin which is stress frozen to passively achieve the quadrature condition. Light, emitted from an LED operating at 820 nm, is transmitted to and from the sensing element via multimode fibers and the signal is detected using a dual channel operational photodiode/amplifier. This unique combination of optics and electronics produces a fiber optic sensor having a high signal to noise ratio which is lead-in/out insensitive. Results show that strains on the order of 1 microstrain can be measured over an 800 microstrain range and that dummy gages can be used for temperature compensation.

  16. Fiber-Optic Chemical Sensors and Fiber-Optic Bio-Sensors

    Science.gov (United States)

    Pospíšilová, Marie; Kuncová, Gabriela; Trögl, Josef

    2015-01-01

    This review summarizes principles and current stage of development of fiber-optic chemical sensors (FOCS) and biosensors (FOBS). Fiber optic sensor (FOS) systems use the ability of optical fibers (OF) to guide the light in the spectral range from ultraviolet (UV) (180 nm) up to middle infrared (IR) (10 µm) and modulation of guided light by the parameters of the surrounding environment of the OF core. The introduction of OF in the sensor systems has brought advantages such as measurement in flammable and explosive environments, immunity to electrical noises, miniaturization, geometrical flexibility, measurement of small sample volumes, remote sensing in inaccessible sites or harsh environments and multi-sensing. The review comprises briefly the theory of OF elaborated for sensors, techniques of fabrications and analytical results reached with fiber-optic chemical and biological sensors. PMID:26437407

  17. Anisotropic Metamaterial Optical Fibers

    CERN Document Server

    Pratap, Dheeraj; Pollock, Justin G; Iyer, Ashwin K

    2014-01-01

    Internal physical structure can drastically modify the properties of waveguides: photonic crystal fibers are able to confine light inside a hollow air core by Bragg scattering from a periodic array of holes, while metamaterial loaded waveguides for microwaves can support propagation at frequencies well below cutoff. Anisotropic metamaterials assembled into cylindrically symmetric geometries constitute light-guiding structures that support new kinds of exotic modes. A microtube of anodized nanoporous alumina, with nanopores radially emanating from the inner wall to the outer surface, is a manifestation of such an anisotropic metamaterial optical fiber. The nanopores, when filled with a plasmonic metal such as silver or gold, greatly increase the electromagnetic anisotropy. The modal solutions in anisotropic circular waveguides can be uncommon Bessel functions with imaginary orders.

  18. Fiber optic TV direct

    Science.gov (United States)

    Kassak, John E.

    1991-01-01

    The objective of the operational television (OTV) technology was to develop a multiple camera system (up to 256 cameras) for NASA Kennedy installations where camera video, synchronization, control, and status data are transmitted bidirectionally via a single fiber cable at distances in excess of five miles. It is shown that the benefits (such as improved video performance, immunity from electromagnetic interference and radio frequency interference, elimination of repeater stations, and more system configuration flexibility) can be realized if application of the proven fiber optic transmission concept is used. The control system will marry the lens, pan and tilt, and camera control functions into a modular based Local Area Network (LAN) control network. Such a system does not exist commercially at present since the Television Broadcast Industry's current practice is to divorce the positional controls from the camera control system. The application software developed for this system will have direct applicability to similar systems in industry using LAN based control systems.

  19. Microstructured optical fiber refractive index sensor

    DEFF Research Database (Denmark)

    Town, Graham E.; McCosker, Ravi; Yuan, Scott Wu; Bang, Ole

    2010-01-01

    We describe a dual-core microstructured optical fiber designed for refractive index sensing of fluids. We show that by using the exponential dependence of intercore coupling on analyte refractive index, both large range and high sensitivity can be achieved in the one device. We also show that...

  20. Selenium semiconductor core optical fibers

    International Nuclear Information System (INIS)

    Phosphate glass-clad optical fibers containing selenium (Se) semiconductor core were fabricated using a molten core method. The cores were found to be amorphous as evidenced by X-ray diffraction and corroborated by Micro-Raman spectrum. Elemental analysis across the core/clad interface suggests that there is some diffusion of about 3 wt % oxygen in the core region. Phosphate glass-clad crystalline selenium core optical fibers were obtained by a postdrawing annealing process. A two-cm-long crystalline selenium semiconductor core optical fibers, electrically contacted to external circuitry through the fiber end facets, exhibit a three times change in conductivity between dark and illuminated states. Such crystalline selenium semiconductor core optical fibers have promising utility in optical switch and photoconductivity of optical fiber array

  1. Selenium semiconductor core optical fibers

    Directory of Open Access Journals (Sweden)

    G. W. Tang

    2015-02-01

    Full Text Available Phosphate glass-clad optical fibers containing selenium (Se semiconductor core were fabricated using a molten core method. The cores were found to be amorphous as evidenced by X-ray diffraction and corroborated by Micro-Raman spectrum. Elemental analysis across the core/clad interface suggests that there is some diffusion of about 3 wt % oxygen in the core region. Phosphate glass-clad crystalline selenium core optical fibers were obtained by a postdrawing annealing process. A two-cm-long crystalline selenium semiconductor core optical fibers, electrically contacted to external circuitry through the fiber end facets, exhibit a three times change in conductivity between dark and illuminated states. Such crystalline selenium semiconductor core optical fibers have promising utility in optical switch and photoconductivity of optical fiber array.

  2. Fiber optic light sensor.

    Science.gov (United States)

    Chudyk, Wayne; Flynn, Kyle F

    2015-06-01

    We describe a low-cost fiber optic sensor for measuring photosynthetically active radiation (PAR) in turbulent flow. Existing technology was combined in a novel way for probe development addressing the need for a small but durable instrument for use in flowing water. Optical components including fiber optics and a wide-spectrum light detector were used to separate light collection from electronic detection so that measurements could be completed in either the field or laboratory, in air or underwater. Connection of the detector to Arduino open-source electronics and a portable personal computer (PC) enabled signal processing and allowed data to be stored in a spreadsheet for ease of analysis. Calibration to a commercial cosine-corrected instrument showed suitable agreement with the added benefit that the small sensor face allowed measurements in tight spaces such as close to the streambed or within leafy or filamentous plant growth. Subsequently, we applied the probe in a separate study where over 35 experiments were successfully completed to characterize downward light attenuation in filamentous algae in turbulent flow. PMID:26009160

  3. Formation and applications of nanoparticles in silica optical fibers

    CERN Document Server

    Blanc, Wilfried

    2015-01-01

    Optical fibers are the basis for applications that have grown considerably in recent years (telecommunications, sensors, fiber lasers, etc). Despite undeniable successes, it is necessary to develop new generations of amplifying optical fibers that will overcome some limitations typical of silica glass. In this sense, the amplifying Transparent Glass Ceramics (TGC), and particularly the fibers based on this technology, open new perspectives that combine the mechanical and chemical properties of a glass host with the augmented spectroscopic properties of embedded nanoparticles. This paper is an opportunity to make a state of the art on silica-based optical fibers containing nanoparticles of various types, particularly rare-earth-doped oxide nanoparticles, and on the methods for making such fibers. In the first section of this article, we will review basics on standard optical fibers and on nanoparticle-doped fibers. In the second section we will recall some fabrication methods used for standard optical fibers, ...

  4. Optical fiber network : Cisco part

    OpenAIRE

    Lu CHEN

    2014-01-01

    This thesis describes a experimental optical fiber network. The thesis was based on the industrial placement work to design a laboratory network. The purpose of this thesis was to provide designs for setting an optical fiber network in the city of Kuopio. The project work was started by searching information and usable technology in the books from the library and the Internet. Most of the broadband and/or fiber optical networks use OSPF together with MPLS as their networking protocols. Th...

  5. Sensing properties of periodic stack of nano-films deposited with various vapor-based techniques on optical fiber end-face

    Science.gov (United States)

    Koba, Marcin; RóŻycki-Bakon, Radosław; Firek, Piotr; Śmietana, Mateusz

    2015-07-01

    This work presents a study on sensing capabilities of stacks of nano-films deposited on a single-mode optical fiber end-faces. The stacks consist of periodically interchanging thin-film layers of materials characterized by different refractive indices (RI). The number of layers is relatively small to encourage light-analyte interactions. Two different deposition techniques are considered, i.e., radio frequency plasma enhanced chemical vapor deposition (RF PECVD) and physical vapor deposition by reactive magnetron sputtering (RMS). The former technique allows to deposit stacks consisting of silicon nitride nano-films, and the latter is well suited for aluminum and titanium oxides alternating layers. The structures are tested for external RI and temperature measurements.

  6. Simulation of a surface plasmon resonance-based fiber-optic sensor for gas sensing in visible range using films of nanocomposites

    International Nuclear Information System (INIS)

    A surface plasmon resonance-based fiber-optic sensor coated with nanocomposite film for sensing small concentrations of gases in the visible region of the electromagnetic spectrum has been analyzed. The nanocomposites considered are nanoparticles of Ag, Au and indium tin oxide (ITO) with their varying fraction dispersed in the host dielectric matrix of WO3, SnO2 and TiO2. For analysis, the effective indices of nanocomposites are calculated by adopting the Maxwell–Garnett model for nanoparticles of dimensions much smaller than the wavelength of radiation used for investigation. The effects of the volume fraction of nanoparticles in different nanocomposites and the thickness of the nanocomposite layer on the sensitivity of the sensor have been studied. It has been found that the sensor with the ITO–TiO2 coated nanocomposite with a small volume fraction and optimized film thickness possesses higher sensitivity

  7. Restraint-free wearable sensing clothes using a hetero-core optic fiber for measurements of arm motion and walking action

    Science.gov (United States)

    Nishiyama, Michiko; Sasaki, Hiroyuki; Watanabe, Kazuhiro

    2007-04-01

    In recent years, unrestrained monitoring human posture and action is a field of increasing interest in the welfare of the elderly and the sport-biomechanics. The scope is this study is that we develop a wearable sensing clothes, which can detect entire body posture and motion using a hetero-core optic fiber sensor. This newly developed sensor can offers several advantages such as the simplicity of structure and fabrication, the stable single mode based operation, the temperature independent property, and the precise loss controllability on given macro bending. These properties are suitable for implementing unrestrained wearable clothes. In this paper, for monitoring flexion of joint without the disturbance of the rucks in the clothes, we proposed and fabricated the improved module structured in the joint ranging 0-90 degree. Additionally, in order to reduce the number of transmission line to be added due to monitoring the whole body posture and motion, we tested that two hetero-core sensors which are tandem placed in a single transmission line have been discriminated by the temporal differential of the optical loss. As a result, we have successfully demonstrated that the wearable sensing clothes could monitor arm motion and human walking without restraint to human daily behavior.

  8. Temperature-independent polymer optical fiber evanescent wave sensor

    OpenAIRE

    Zhong, Nianbing; Liao, Qiang; Zhu, Xun; Zhao, Mingfu; Yun HUANG; Chen, Rong

    2015-01-01

    Although the numerous advantages of polymer optical fibers have been exploited in the fields of sensors and telecommunications, such fibers still experience a critical problem: the temperature dependency. Therefore, we explored the temperature-independent operation of a polymer fiber-optic evanescent wave sensor immersed in distilled water. We investigated variations in the surface morphology, deformation trajectory, refractive index, and weight of the fiber-sensing region with varying water ...

  9. Fiber structure based on a depressed inner cladding fiber for bend, refractive index and temperature sensing

    International Nuclear Information System (INIS)

    A fiber-optic structure based on a section of a double-clad fiber with depressed inner cladding is investigated for bend, refractive index and temperature sensing. The structure is formed by splicing a section of SM630 fiber between two standard fibers SMF-28. The operation principle relies on the sensitivity of cladding modes that are induced at a splice of fibers having different refractive index profiles. The mode structure of the double cladding fiber and the mechanism of formation of dips in the transmission spectra are discussed. The transmission spectra of the structure are measured for different curvatures of the inserted fiber section. The shift of dips to long wavelengths with increasing curvature of the fiber is observed and its dependence on the fiber section length and the direction of bending is investigated. The sensitivities of the spectral dips to the external refractive index and temperature are also measured. (paper)

  10. Fiber optics chemical sensor FOCA 2000

    Science.gov (United States)

    Brunner, Robert J.; Doupovec, Juraj; Kvasnik, Frank

    1999-07-01

    A modular fiberoptic sensorial instrument for (bio-)chemical analyses will be presented. The sensing mechanism is based on Capillary Optical Fiber (COF). A measurand of liquids or gaseous form present in the COF cavity influences the chemical transducer covering the inner wall of fiber, and by this way changes the intensity of guided radiation. The wavelength scanning through the characteristic region enables the identification and quantitative analysis of the measurand. Every COF modulus is sesibilized for specific chemicals. The application of new immobilized chemical transducer and theoretical description of the sensing effects will be presented, too.

  11. Communicating On The Moon Via Fiber Optics

    Science.gov (United States)

    Lutes, George F.

    1992-01-01

    Report discusses feasibility of communicating over long distances on Moon via fiber optics. Compares fiber-optic and microwave technologies, concluding fiber optics offer less consumption of power, less weight, less bulk, and lower cost. Present commercial fiber-optic technology appears usable on Moon with minor modifications. Includes tutorial chapter on fiber-optic-communication technology and chapter on efforts to improve technology.

  12. Chemical Sensing Using Fiber Cavity Ring-Down Spectroscopy

    Directory of Open Access Journals (Sweden)

    Hans-Peter Loock

    2010-03-01

    Full Text Available Waveguide-based cavity ring-down spectroscopy (CRD can be used for quantitative measurements of chemical concentrations in small amounts of liquid, in gases or in films. The change in ring-down time can be correlated to analyte concentration when using fiber optic sensing elements that change their attenuation in dependence of either sample absorption or refractive index. Two types of fiber cavities, i.e., fiber loops and fiber strands containing reflective elements, are distinguished. Both types of cavities were coupled to a variety of chemical sensor elements, which are discussed and compared.

  13. Optical Sensors Based on Plastic Fibers

    Directory of Open Access Journals (Sweden)

    Rogério Nogueira

    2012-09-01

    Full Text Available The recent advances of polymer technology allowed the introduction of plastic optical fiber in sensor design. The advantages of optical metrology with plastic optical fiber have attracted the attention of the scientific community, as they allow the development of low-cost or cost competitive systems compared with conventional technologies. In this paper, the current state of the art of plastic optical fiber technology will be reviewed, namely its main characteristics and sensing advantages. Several measurement techniques will be described, with a strong focus on interrogation approaches based on intensity variation in transmission and reflection. The potential applications involving structural health monitoring, medicine, environment and the biological and chemical area are also presented.

  14. Optimize Etching Based Single Mode Fiber Optic Temperature Sensor

    OpenAIRE

    Ajay Kumar; Dr. Pramod Kumar

    2014-01-01

    This paper presents a description of etching process for fabrication single mode optical fiber sensors. The process of fabrication demonstrates an optimized etching based method to fabricate single mode fiber (SMF) optic sensors in specified constant time and temperature. We propose a single mode optical fiber based temperature sensor, where the temperature sensing region is obtained by etching its cladding diameter over small length to a critical value. It is observed that th...

  15. Investigations on birefringence effects in polymer optical fiber Bragg gratings

    DEFF Research Database (Denmark)

    Hu, Xiaolian; Saez-Rodriguez, D.; Bang, Ole; Webb, D. J.; Caucheteur, C.

    2014-01-01

    Step-index polymer optical fiber Bragg gratings (POFBGs) and microstructured polymer optical fiber Bragg gratings (mPOFBGs) present several attractive features, especially for sensing purposes. In comparison to FBGs written in silica fibers, they are more sensitive to temperature and pressure because of the larger thermo-optic coefficient and smaller Young's modulus of polymer materials. (M)POFBGs are most often photowritten in poly(methylmethacrylate) (PMMA) materials using a continuous-wave 32...

  16. Optical Fiber Sensors for Smart Structures : A Review

    Directory of Open Access Journals (Sweden)

    P. Kundu

    1996-10-01

    Full Text Available This review describes recent advances in optical fiber sensors for smart structures. After discussing the fabrication on technology and strain sensing of fiber-optic sensors in a brief introduction, the detailed accounts of signal processing techniques employed in them are given. The application areas of fiber-optic sensors are also described briefly with necessary references. Future trend of work is indicated in the concluding remarks.

  17. Fundamentals of plastic optical fibers

    CERN Document Server

    Koike, Yasuhiro

    2014-01-01

    Polymer photonics is an interdisciplinary field which demands excellence both in optics (photonics) and materials science (polymer). However, theses disciplines have developed independently, and therefore the demand for a comprehensive work featuring the fundamentals of photonic polymers is greater than ever.This volume focuses on Polymer Optical Fiber and their applications. The first part of the book introduces typical optical fibers according to their classifications of material, propagating mode, and structure. Optical properties, the high bandwidth POF and transmission loss are discussed,

  18. Fluorescing optical fibers and uses

    International Nuclear Information System (INIS)

    Present available industrial Plastic Optical Fibers are made of an optical core of either Poly Methyl Methacrylate, Polystyrene, or Polycarbonate. Three main fiber families are produced: - transparent fibers, used to transmit light or signals; - scintillating fibers, doped with two or more dopants to let them able to detect particles by radiating blue or green light, measured with a photomultiplier; - fluorescent fibers, doped with a single dopant, and able to shift the ambient incident radiation into another radiation of longer wavelength. New PS core fluorescent fibers are made so far with different absorption and fluorescent reemission wavelength bands. Some optical characteristics of the materials employed for blue, green, yellow, orange fibers are described. Applications in the light sensors field already exist such as light intensity detectors for electric arcs, fog or particle detectors

  19. Temperature sensing on tapered single mode fiber using mechanically induced long period fiber gratings

    Science.gov (United States)

    Marrujo-García, Sigifredo; Velázquez-González, Jesús Salvador; Pulido-Navarro, María. Guadalupe; González-Ocaña, Ernesto; Mújica-Ascencio, Saúl; Martínez-Piñón, Fernando

    2015-09-01

    The modeling of a temperature optical fiber sensor is proposed and experimentally demonstrated in this work. The suggested structure to obtain the sensing temperature characteristics is by the use of a mechanically induced Long Period Fiber Grating (LPFG) on a tapered single mode optical fiber. A biconical fiber optic taper is made by applying heat using an oxygen-propane flame burner while stretching the single mode fiber (SMF) whose coating has been removed. The resulting geometry of the device is important to analyze the coupling between the core mode to the cladding modes, and this will determine whether the optical taper is adiabatic or non-adiabatic. On the other hand, the mechanical LPFG is made up of two plates, one grooved and other flat, the grooved plate was done on an acrylic slab with the help of a computerized numerical control machine (CNC). In addition to the experimental work, the supporting theory is also included.

  20. Temperature Response of a Small Mountain Stream to Thunderstorm Cloud-Cover: Application of DTS Fiber-Optic Temperature Sensing

    Science.gov (United States)

    Thayer, D.; Klatt, A. L.; Miller, S. N.; Ohara, N.

    2014-12-01

    From a hydrologic point of view, the critical zone in alpine areas contains the first interaction of living systems with water which will flow to streams and rivers that sustain lowland biomes and human civilization. A key to understanding critical zone functions is understanding the flow of energy, and we can measure temperature as a way of looking at energy transfer between related systems. In this study we installed a Distributed Temperature Sensor (DTS) and fiber-optic cable in a zero-order stream at 9,000 ft in the Medicine Bow National Forest in southern Wyoming. We measured the temperature of the stream for 17 days from June 29 to July 16; the first 12 days were mostly sunny with occasional afternoon storms, and the last 5 experienced powerful, long-lasting storms for much of the day. The DTS measurements show a seasonal warming trend of both minimum and maximum stream temperature for the first 12 days, followed by a distinct cooling trend for the five days that experienced heavy storm activity. To gain insights into the timing and mechanisms of energy flow through the critical zone systems, we analyzed the timing of stream temperature change relative to solar short-wave radiation, and compared the stream temperature temporal response to the temporal response of soil temperature adjacent to the stream. Since convective thunderstorms are a dominant summer weather pattern in sub-alpine regions in the Rocky Mountains, this study gives us further insight into interactions of critical zone processes and weather in mountain ecosystems.

  1. Fiber optic combiner and duplicator

    Science.gov (United States)

    1979-01-01

    The investigation of the possible development of two optical devices, one to take two images as inputs and to present their arithmetic sum as a single output, the other to take one image as input and present two identical images as outputs is described. Significant engineering time was invested in establishing precision fiber optics drawing capabilities, real time monitoring of the fiber size and exact measuring of fiber optics ribbons. Various assembly procedures and tooling designs were investigated and prototype models were built and evaluated that established technical assurance that the device was feasible and could be fabricated. Although the interleaver specification in its entirety was not achieved, the techniques developed in the course of the program improved the quality of images transmitted by fiber optic arrays by at least an order of magnitude. These techniques are already being applied to the manufacture of precise fiber optic components.

  2. Fiber optic sensor and method for making

    Science.gov (United States)

    Vartuli, James Scott; Bousman, Kenneth Sherwood; Deng, Kung-Li; McEvoy, Kevin Paul; Xia, Hua

    2010-05-18

    A fiber optic sensor including a fiber having a modified surface integral with the fiber wherein the modified surface includes an open pore network with optical agents dispersed within the open pores of the open pore network. Methods for preparing the fiber optic sensor are also provided. The fiber optic sensors can withstand high temperatures and harsh environments.

  3. Evaluation of the heat-storage capability of shallow aquifers using active heat tracer tests and Fiber-Optics Distributed-Temperature-Sensing

    Science.gov (United States)

    Suibert Oskar Seibertz, Klodwig; Chirila, Marian Andrei; Bumberger, Jan; Dietrich, Peter; Vienken, Thomas

    2015-04-01

    In the course of the energy transition, geothermal energy storage and heat generation and cooling have proven to be environmental friendly alternatives to conventional energy. However, to ensure sustain usage, the heat transport behavior of aquifers and its distribution has to be studied. A tool to achieve this is the active heat tracer test, eg. Leaf et al. (2012). If active heat tracer tests are combined with in aquifer heat testing via electric heating-cables, eg. Liu et al. (2013), it is possible to observe heat transport and temperature signal decay without disturbing the original pressure field within the aquifer. In this field study a two channel High-Resolution-Fiber-Optic-Distributed-Temperature-Sensing and Pt100 were used to measure temperature signals within in two wells of 1.4 m distance, where the temperature difference was generated using a self regulating heating cable in the upstream well. High resolution Distributed-Temperature-Sensing measurements were achieved by coiling the fiber around screened plastic tubes. The upstream well was also used to observe heating (? Tmax approx. 24K) and temperature signal decay, while the downstream well was used to observe heat transport between both wells. The data was analyzed and compared to thermal conductivity of soil samples and Direct-Push (DP) Electrical-Conductivity-Logging and DP Hydraulic-Profiling results. The results show good agreement between DP data and temperature measurements proving the active heat tracer test is a suitable tool for providing reliable information on aquifer heat-storage capability. References Leaf, A.T., Hart, D.J., Bahr, J.M.: Active Thermal Tracer Tests for Improved Hydrostratigraphic Characterization. Ground Water, vol. 50, 2012 Liu, G., Knobbe, S., Butler, J.J.Jr.: Resolving centimeter-scale flows in aquifers and their hydrostratigraphic controls. Geophysical Research Letters, vol. 40, 2013

  4. Spatial and temporal resolution requirements for quench detection in (RE)Ba2Cu3Ox magnets using Rayleigh-scattering-based fiber optic distributed sensing

    Science.gov (United States)

    Chan, W. K.; Flanagan, G.; Schwartz, J.

    2013-10-01

    One of the key remaining challenges to safe and reliable operation of large, high temperature superconductor (HTS)-based magnet systems is quench detection and protection. Due to the slow quench propagation in HTS systems, the conventional discrete voltage-tap approach developed for NbTi and Nb3Sn magnets may not be sufficient. In contrast, a distributed temperature profile, generated by a distributed temperature sensor and facilitating continuous monitoring of the temperature at any monitored locations within a magnet with high spatial resolution, may be required. One such distributed temperature sensing option is the use of Rayleigh-based fiber optic sensors (FOS), which are immune to electromagnetic interference. The detection of a quench via Rayleigh-based FOS relies on converting the spectral shifts in the Rayleigh scattering spectra into temperature variations. As a result, the higher the spatial sampling resolution the larger the data processing volume, and thus the lower the temporal sampling resolution. So, for effective quench detection, which requires the quick and accurate identification of a hot spot, it is important to find a balance between the spatial and temporal resolutions executable on a given data acquisition and processing (DAQ) system. This paper discusses a method for finding an appropriate DAQ technology that matches the characteristic of a superconducting coil, and determining the acceptable resolutions for efficient and safe quench detection. A quench detection algorithm based on distributed temperature sensing is proposed and its implementation challenges are discussed.

  5. Fiber optic hydrogen sensor

    Energy Technology Data Exchange (ETDEWEB)

    Butler, M.A.; Sanchez, R.; Dulleck, G.R.

    1996-05-01

    This report covers the development of fiber optic hydrogen and temperature sensors for monitoring dissolved hydrogen gas in transformer oil. The concentration of hydrogen gas is a measure of the corona and spark discharge within the transformer and reflects the state of health of the transformer. Key features of the instrument include use of palladium alloys to enhance hydrogen sensitivity, a microprocessor controlled instrument with RS-232, liquid crystal readout, and 4-20 ma. current loop interfaces. Calibration data for both sensors can be down loaded to the instrument through the RS-232 interface. This project was supported by the Technology Transfer Initiative in collaboration with J. W. Harley, Inc. through the mechanism of a cooperative research and development agreement (CRADA).

  6. Data acquisition with fiber optic sensors

    Science.gov (United States)

    Kist, R.

    The advantages of using fiber optic sensors for data acquisition are discussed, and their present utilization in this area is examined. Because of their high cost, these sensors are not likely to be competitive in general metrological applications in the near future. They do, however, provide important advantages in specific areas such as isolation against high voltage and immunity against electromagnetic fields and explosive and/or corrosive environments. They also offer the possibility of miniaturized and compact packaging of the sensing element an application within a broad temperature range. Multimode fiber optic sensors for parameters such as temperature, pressure, and refractive index have more immediate commercial potential than monomode fiber optic sensors, which have higher costs. The latter allow for high precision solutions of metrological tasks under specific conditions, and will be utilized in the foreseeable future.

  7. AGV guidance by fiber optic tactility

    Science.gov (United States)

    Djordjevich, Alexandar; Tso, Shiu K.; Zhu, H. Y.; Pjevalica, V.

    1999-11-01

    In order to increase the tactile sensing range and allow larger AGV speeds that result in larger vehicle stopping distances, the recently reported fiber-optic 'curvature gauges' sensitized to their geometric curvature are arranged in loops around the AGV. When the AGV is driven into other objects, these loops deform, resulting in the change of their curvature - which is registered. While many different types of bumpers and whiskers have been sued in the past for a similar purpose, the key difference here is that no intermediate mechanical elements are employed to either transfer the impact loads onto the sensitive element or provide compliance to it. Optical fibers themselves provide both functions simultaneously. As a result, tactility is achieved within a comparatively large range extending over 10 cm. Throughout this range, virtually no reaction forces are generated with the impacting body. The range mentioned is on top of the one provided by the more traditional elastic bumper the optical fibers are mounted on.

  8. Integrated optical fiber shape sensor modules based on twisted multicore fiber grating arrays

    Science.gov (United States)

    Westbrook, P. S.; Feder, K. S.; Kremp, T.; Taunay, T. F.; Monberg, E.; Kelliher, J.; Ortiz, R.; Bradley, K.; Abedin, K. S.; Au, D.; Puc, G.

    2014-02-01

    In this paper we report on the development of a complete integrated optical fiber assembly suitable for shape sensing. Our shape sensor module consists of a length (>1m) of twisted multicore optical fiber with fiber Bragg gratings inscribed along its length. Our fiber has a compact 180 micron coated diameter, a twist of 50 turns per meter and grating reflectivities greater than 0.01% per cm of array, suitable for high efficiency scatter measurements over many meters of fiber. Single core to multicore fanouts and low reflectivity fiber termination are used to terminate the end of the array.

  9. Sensing via optical interference

    Directory of Open Access Journals (Sweden)

    Ryan C. Bailey

    2005-04-01

    Full Text Available Chemical and biological sensing are problems of tremendous contemporary technological importance in multiple regulatory and human health contexts, including environmental monitoring, water quality assurance, workplace air quality assessment, food quality control, many aspects of biodiagnostics, and, of course, homeland security. Frequently, what is needed, or at least wanted, are sensors that are simultaneously cheap, fast, reliable, selective, sensitive, robust, and easy to use. Unfortunately, these are often conflicting requirements. Over the past few years, however, a number of promising ideas based on optical interference effects have emerged. Each is based to some extent on advances in the design and fabrication of functional materials. Generally, the advances are of two kinds: chemo- and bio-selective recognition and binding, and efficient methods for micropatterning or microstructuring.

  10. Fiber optic strain measurement for machine monitoring

    Science.gov (United States)

    Hoffmann, L.; Mueller, M. S.; Koch, A. W.

    2007-06-01

    Monitoring machines during operation is an important issue in measurement engineering. The usual approach to monitoring specific machine components is using strain gauges. Strain gauges, however, may sometimes not be used if conditions are harsh or installation space is limited. Fiber optic sensors seem to be an alternative here, but dynamic health monitoring has been dificult so far. The focus of this field study is to measure vibration characteristics of machine parts during operation using fiber optic sensors with the objective of early damage detection. If that was possible, downtime and maintenance costs could be minimized. Therefore a field test for dynamic fiber optic strain measurement on a roller bearing was carried out. The test setup consisted of the bearing built into a gear test stand and equipped with an array of fiber Bragg grating sensors. Fifteen fiber sensors were interrogated with a sample rate of 1 kHz and the vibration pattern was extracted. The radial load distribution was measured with high spatial resolution and a high degree of compliance with simulation data was found. The findings suggest that fiber optic health monitoring for machine components is feasible and reasonable. Especially with the help of distributed sensing on various components extensive health monitoring on complex technical systems is possible.

  11. Fiber optic-based biosensor

    Science.gov (United States)

    Ligler, Frances S.

    1991-01-01

    The NRL fiber optic biosensor is a device which measures the formation of a fluorescent complex at the surface of an optical fiber. Antibodies and DNA binding proteins provide the mechanism for recognizing an analyze and immobilizing a fluorescent complex on the fiber surface. The fiber optic biosensor is fast, sensitive, and permits analysis of hazardous materials remote from the instrumentation. The fiber optic biosensor is described in terms of the device configuration, chemistry for protein immobilization, and assay development. A lab version is being used for assay development and performance characterization while a portable device is under development. Antibodies coated on the fiber are stable for up to two years of storage prior to use. The fiber optic biosensor was used to measure concentration of toxins in the parts per billion (ng/ml) range in under a minute. Immunoassays for small molecules and whole bacteria are under development. Assays using DNA probes as the detection element can also be used with the fiber optic sensor, which is currently being developed to detect biological warfare agents, explosives, pathogens, and toxic materials which pollute the environment.

  12. Classification of Fiber Optical Sensors

    Directory of Open Access Journals (Sweden)

    Shivang Ghetia

    2013-07-01

    Full Text Available Fiber optics sensor technology offers different parameter measurements such as strain, pressure, temperature, current and many more things. For that different type of sensors are used and these sensors converts these parameters to optical parameters like light intensity or phase or polarization of light. These converted parameters are transmitted using an optical link over a long distance. In this paper, we review optical sensors and their applications. Here, we describe the classification of fiber optic sensors and based on these sensors, some applications of them are discussed.

  13. Research progress of photonic crystal fibers for gas sensing

    Science.gov (United States)

    Lv, Lei; Wei, Yubin; Liu, Tongyu

    2013-09-01

    Because of its special structure, photonic crystal fiber(PCF) has shown great potential in gas sensing. Probe beam with the test gas can directly interact within a PCF. PCF gas sensor with a very small amount of gas can be interact with light in optical fiber in a long distance. And you can change the parameters of the fibers can be improved sensor sensitivity, etc. The status of solid core PCF and hollow-core PCF as a gas sensor is introduced respectively in this paper.

  14. Silica optical fibers: technology update

    Science.gov (United States)

    Krohn, David A.; McCann, Brian P.

    1995-05-01

    Silica-core optical fibers have long been the standard delivery medium for medical laser delivery systems. Their high strength, excellent flexibility, and low cost continue to make them the fiber of choice for systems operating from 300 to 2200 nm. An overview of the current fiber constructions available to the industry is reviewed. Silicone-clad fibers, hard- fluoropolymer clad fibers and silica-clad fibers are briefly compared in terms of mechanical and optical properties. The variety of fiber coatings available is also discussed. A significant product development of silica fiber delivery systems has been in side-firing laser delivery systems for Urology. These devices utilize silica-core fibers to project the laser energy at a substantial lateral angle to the conventional delivery system, typically 40 to 100 degrees off axis. Many unique distal tips have been designed to meet the needs of this potentially enormous application. There are three primary technologies employed in side-firing laser delivery systems: reflection off of an attached medium; reflection within an angle-polished fiber through total internal reflection; and reflection from both an angle-polished fiber and an outside medium. Each technology is presented and compared on the basis of operation modality, transmission efficiency, and power-handling performance.

  15. Fiber laser systems for space lasercom and remote sensing

    Science.gov (United States)

    Gupta, Shantanu; Engin, Doruk; Puffenberger, Kent; Litvinovich, Slava; Kimpel, Frank; Utano, Rich

    2013-09-01

    Space based laser remote-sensing for Earth observation and planetary atmospheres has traditionally relied on the mature diode-pumped solid-state laser and nonlinear frequency conversion technology. We highlight representative examples, including ongoing space mission programs at Fibertek. Key design issues are highlighted, and the lessons learned from a multi-disciplinary design process addressing the space-qualification requirements. Fiber laser/amplifier system provides an agile optical platform for space based laser applications ? space lasercom, space-based Earth (or planetary) remote sensing, and space-based imaging. In particular we discuss ongoing efforts at Fibertek on a space-qualifiable, high-performance 1.5-?m Er-doped fiber laser transmitter for inter-planetary lasercom. Design and performance for space qualification is emphasized. As an example of an agile laser platform, use of above fiber laser/amplifier hardware platform for space based sensing of atmospheric CO2 is also highlighted.

  16. Respiratory function monitoring using a real-time three-dimensional fiber-optic shaping sensing scheme based upon fiber Bragg gratings

    OpenAIRE

    Allsop, T.; Bhamber, R.; LLOYD, G.; Miller, M. R.; Dixon, A.; Webb, D; Ania Castañón, Juan Diego; Bennion, I (Ian)

    2012-01-01

    An array of in-line curvature sensors on a garment is used to monitor the thoracic and abdominal movements of a human during respiration. The results are used to obtain volumetric changes of the human torso in agreement with a spirometer used simultaneously at the mouth. The array of 40 in-line fiber Bragg gratings is used to produce 20 curvature sensors at different locations, each sensor consisting of two fiber Bragg gratings. The 20 curvature sensors and adjoining fiber are encapsulated in...

  17. Simultaneous single-fiber communications and linear position sensing

    Science.gov (United States)

    Fuhr, Peter L.; Kajenski, Peter J.; Huston, Dryver J.; Spillman, William B.

    1992-02-01

    The use of a single multimode optical fiber is investigated for simultaneous high-data-rate optical communications and linear displacement sensing. The technique is based on and an extension of the combination of single analog tone frequency and modal-domain vibration sensing. Digital pseudorandom-bit sequences are employed for the data transmission at several standard telecommunication speeds. The position of an in-line fiberoptic displacement sensor is determined by examining variations in the data-stream bit-error rate for the cases of both static and dynamic displacements. It is shown that a single multimode fiber can be utilized simultaneously as both a linear-displacement sensor and a communication link. Fiber faults can be located to a resolution of 3 m at the 34-Mbaud rate, and the cost-effectiveness of multiplexing sensor and communications systems is noted.

  18. Optical Fiber Grating based Sensors

    OpenAIRE

    Michelsen, Susanne

    2006-01-01

    In this thesis differenct optical fiber gratings are used for sensor purposes. If a fiber with a core concentricity error (CCE) is used, a directional dependent bend sensor can be produced. The CCE direction can be determined by means of diffraction. This makes it possible to produce long-period gratings in a fiber with a CCE direction parallel or perpendicular to the writing direction. The maximal bending sensitivity is independent on the writing direction, but the detailed bending response ...

  19. Fiber optic pressure sensors for nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Hashemian, H.M.; Black, C.L. [Analysis and Measurement Services Corp., Knoxville, TN (United States)

    1995-04-01

    In the last few years, the nuclear industry has experienced some problems with the performance of pressure transmitters and has been interested in new sensors based on new technologies. Fiber optic pressure sensors offer the potential to improve on or overcome some of the limitations of existing pressure sensors. Up to now, research has been motivated towards development and refinement of fiber optic sensing technology. In most applications, reliability studies and failure mode analyses remain to be exhaustively conducted. Fiber optic sensors have currently penetrated certain cutting edge markets where they possess necessary inherent advantages over other existing technologies. In these markets (e.g. biomedical, aerospace, automotive, and petrochemical), fiber optic sensors are able to perform measurements for which no alternate sensor previously existed. Fiber optic sensing technology has not yet been fully adopted into the mainstream sensing market. This may be due to not only the current premium price of fiber optic sensors, but also the lack of characterization of their possible performance disadvantages. In other words, in conservative industries, the known disadvantages of conventional sensors are sometimes preferable to unknown or not fully characterized (but potentially fewer and less critical) disadvantages of fiber optic sensors. A six-month feasibility study has been initiated under the auspices of the US Nuclear Regulatory Commission (NRC) to assess the performance and reliability of existing fiber optic pressure sensors for use in nuclear power plants. This assessment will include establishment of the state of the art in fiber optic pressure sensing, characterization of the reliability of fiber optic pressure sensors, and determination of the strengths and limitations of these sensors for nuclear safety-related services.

  20. Polymer optical fiber bragg grating sensors

    DEFF Research Database (Denmark)

    Stefani, Alessio; Yuan, Scott Wu; Andresen, Søren; Bang, Ole

    2010-01-01

    Fiber-optical accelerometers based on polymer optical fiber Bragg gratings are reported. We have written fiber Bragg gratings for 1550 nm and 850 nm operations, characterized their temperature and strain response, and tested their performance in a prototype accelerometer....

  1. Fabrication and characterization of fiber optical components for application in guiding, sensing and molding of THz and mid-IR radiation

    Science.gov (United States)

    Mazhorova, Anna

    The terahertz (THz) range refers to electromagnetic waves with frequencies between 100 GHz and 10 THz, or wavelengths between 3 mm and 30 µm. Light between radio waves and infrared has some unique properties. Within the scope of this work I would like to address three main research topics. In Chapter 2, I describe fabrication method and THz characterization of composite films containing either aligned metallic (tin alloy) microwires or chalcogenide As2Se3 microwires. The microwire arrays are made by stack-and-draw fiber fabrication technique using multi-step co-drawing of low-melting-temperature metals or semiconductor glasses together with polymers. Fibers are then stacked together and pressed into composite films. Transmission through metamaterial films is studied in the whole THz range (0.1-20 THz) using a combination of FTIR and TDS. Metal containing metamaterials are found to have strong polarizing properties, while semiconductor containing materials are polarization independent and could have a designable high refractive index. Using the transfer matrix theory, it was shown how to retrieve the complex polarization dependent refractive index of the composite films. We then detail the selfconsistent algorithm for retrieving the optical properties of the metal alloy used in the fabrication of the metamaterial layers by using an effective medium approximation. Finally, we study challenges in fabrication of metamaterials with sub-micrometer metallic wires by repeated stack-and-draw process by comparing samples made using 2, 3 and 4 consecutive drawings. When using metallic alloys we observe phase separation effects and nano-grids formation on small metallic wires. In Chapter 3, we have studied fabrication and bacteria detection application of the lowloss subwavelength THz microstructured fibers. One of the key difficulties in the design of terahertz waveguides lies in the fact that almost all materials are highly absorbing in the terahertz region. Since the lowest absorption loss occurs in dry gases, an efficient waveguide design must maximize the fraction of power guided in the gas. Different types of THz waveguides have been proposed based on this concept including a subwavelength waveguide featuring a core with a size much smaller than the wavelength of light in which a large fraction of the guided light is found outside of the lossy core region. A practical design of such a waveguide was recently proposed in our research group and presents a subwavelength fiber suspended on thin bridges in the middle of a larger protective tube. Large channels formed by the bridges and a tube make a convenient opto-microfluidic system that is easy to fill with liquid analytes or purge with dry gases. Particularly, the THz subwavelength waveguide used in our experiments features a 150 µm core fiber suspended by three 20 µm-thick bridges in the center of a 5.1 mm diameter tube of 4 cm in length. This waveguide design presents several important advantages for bio-sensing applications. First, the waveguide structure allows direct and convenient access to the fiber core and to the evanescent wave guided around it. Second, the outer cladding effectively isolates the core-guided mode from the surrounding environment, (e.g. fiber holders), thereby preventing the undesirable external perturbations of the terahertz signal. Finally, in Chapter 4, low-loss chalcogenide capillary-based waveguides that operate both in the mid-IR and THz spectral ranges are investigated. Chalcogenide glasses have attracted strong interest in a view of optical applications in the near-IR and mid-IR spectral ranges (1-14 µm) due to their relatively low losses and high nonlinearities. Furthermore, chalcogenide glass-based microstructured fibers open many interesting possibilities for a large number of applications in the mid-IR spectral range, where applications in optical sensing, supercontinuum generation and single-mode propagation of IR light, transmission of the CO and CO2 laser radiation have already been demonstrated. We believe that chalcogenide glasses c

  2. Mobile fiber optic emission spectrograph

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, W.A.; Coleman, C.J.; McCarty, J.E.; Beck, R.S.

    1997-05-01

    Technical Assistance Request HLW/DWPF-TAR-970064 asked SRTC to evaluate the use of a fiber optic coupled emission spectrometer. The spectrometer would provide additional ICP analyses in the DWPF laboratory.

  3. Scintillator fiber optic long counter

    Science.gov (United States)

    McCollum, Tom (Sterling, VA); Spector, Garry B. (Fairfax, VA)

    1994-01-01

    A flat response position sensitive neutron detector capable of providing neutron spectroscopic data utilizing scintillator fiber optic filaments embedded in a neutron moderating housing having an open end through which neutrons enter to be detected.

  4. Radiation damage in optical fibers

    International Nuclear Information System (INIS)

    While plastic-clad-silica (PCS) fiber shows the greatest radiation resistance, PCS fiber has been difficult to reliably connectorize for routine field operations. For this reason, all-glass fibers have been studied as an alternative to PCS. Based on available literature and some preliminary tests at Los Alamos, we have concentrated on fluorosilicate clad, step index, pure silica core fibers. This paper reviews recent laboratory data for these fibers relative to the PCS fibers. This paper also discusses use of a fiber (or any optical medium) on a Cerenkov radiation-to-light transducer. Since the radiation induces attenuation in the medium, the light output is not proportional to the radiation input. The nonlinearity introduced by this attenuation is calculated

  5. High Precision Displacement Measurement Using Fiber Optics

    CERN Document Server

    Berkovic, G; Scandale, Walter; Shafir, E; Todesco, Ezio

    2002-01-01

    We describe laboratory experiments with a fiber-optic sensor employing a chirped laser that detects, with 20-30 micrometer accuracy, displacements of a remote reflective target at distance of 200-500 mm. The requirements of chirp linearity and laser coherence in order to achieve this sensitivity are elaborated. This sensor can be employed for remotely sensing minute displacements of objects in harsh environments, including cryo-magnets in particle accelerators.

  6. Small Business Innovations (Fiber Optics)

    Science.gov (United States)

    1991-01-01

    Foster-Miller, Inc. Waltham, MA developed the In-Situ Fiber Optic Polymer Reaction Monitor which could lead to higher yields and lower costs in complex composite manufacturing. The monitor, developed under a Small Business Innovation Research (SBIR) contract with Langley Research Center, uses an infrared, fiber optic sensor to track the molecular vibrational characteristics of a composite part while it is being cured. It is the first analytical system capable of directly measuring the chemistry of advanced composite materials.

  7. An Efficient Wavelength variation approach for Bend Sensing in Single mode- Multimode-Single mode Optical Fiber Sensors

    OpenAIRE

    Abdul Samee Khan,; Mohd. Sarwar Raeen,

    2012-01-01

    Several aspects of the SMS edge filters have been investigated, including the effect of bending the SMS fiber cores due to fabrication tolerances, polarization dependence, and temperature dependence. These aspects can impair the performance of a wavelength measurement system. There are several approaches which have been proposed and demonstrated to achieve high resolution and accuracy of wavelength measurement. Bending effects due to the splicing process on the spectral characteristics of SMS...

  8. Using high-resolution fiber-optic distributed temperature sensing to measure spatially resolved speed and temperature of airflows in a shallow gully

    Science.gov (United States)

    Thomas, Christoph; Sayde, Chadi; Selker, John

    2015-04-01

    We present a novel observational technique that was applied to study transient shallow cold-air drainages and pools in undulating terrain in weak-wind conditions. Wind speed and air temperature at thousands of closely co-located locations were measured simultaneously at high spatial (0.25m) and temporal (5s) resolution using paired passive and actively heated optical fibers with a distributed temperature sensing system (DTS). The fibers were deployed in a transect across a shallow gully with a total length of 230 m at three levels (0.5, 1, and 2m above ground level) during the Shallow Cold Pool (SCP) Experiment in Northern Colorado, USA in October and November 2012. While we previously demonstrated that air temperature and the thermal structure of the near-surface turbulence can be observed with the DTS technique (Thomas et al., 2012, Zeeman et al., 2014), the novelty here consists of additionally measuring wind speed on horizontal scales of several hundreds of meters with fine resolution. Analogous to a hot-wire anemometer, the approach is based on the principal of velocity-dependent heat transfer from a heated surface. We present the theoretical basis for the DTS wind and temperature measurements and validate it against point observations from sonic anemometers and thermo-hygrometers. A space-time analysis of the near-surface gully flow and temperature field is presented based upon the observations subject to an orthogonal multi-resolution decomposition for selected cases. The temporal variability of near-surface air temperature was largest half-way up the slope caused be shifts of the very sharp thermal boundary between the density driven cold-air drainage flow in the gully bottom and the lower density air on the slopes, which was significantly warmed by enhanced downward mixing of sensible heat in the lee of the gully shoulder. Stationary horizontal temperature gradients at this thermal boundary amounted to 6 to 8 K m-1 and persisted for several hours unless the cold-air pool was displaced from the gully by intermittently strong external wind forcing. Even gentle surface heterogeneity can have dramatic impacts on the structure of the near-surface flow, turbulence, and heat transport, which calls for spatial observations to quantify and compensate for the location bias of traditional single-point flow and flux measurements. The novel approach, which allows studying the spatial structure of the surface layer on scales spanning four orders of magnitude (0.1 - 1000m), opens up many important opportunities for testing fundamental assumptions and concepts in micrometeorology including, but not limited to turbulent length scales, the validity of Taylors hypothesis and ergodicity, surface heterogeneity, and internal boundary layers. References: Thomas, C.K., Kennedy, A.M., Selker, J.S., Moretti, A., Schroth, M.H., Smoot, A.R., Tufillaro, N.B., Zeeman, M.J., 2012. High-resolution fibre-optic temperature sensing: A new tool to study the two-dimensional structure of atmospheric surface layer flow. Boundary-Layer Meteorol. 142, 177-192. DOI: 10.1007/s10546-011-9672-7 Zeeman MJ, Selker JS, Thomas CK. Near-surface motion in the nocturnal, stable boundary layer observed with fibre-optic distributed temperature sensing. Boundary- Layer Meterology. 2014:online first. doi:10.1007/s10546-014-9972-9.

  9. Power system applications of fiber optic sensors

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, A.R.; Jackson, S.P.; Kirkham, H.; Yeh, C.

    1986-06-01

    Three topics are covered: Electric Field Measurement, Fiber Optic Temperature Sensing, and Optical Power Transfer. Work was done on the measurement of ac and dc electric fields. A prototype sensor for measuring alternating fields was made using a very simple electroscope approach. An electronic field mill sensor for dc fields was made using a fiber optic readout, so that the entire probe could be operated isolated from ground. There are several instances in which more precise knowledge of the temperature of electrical power apparatus would be useful. This report describes a number of methods whereby the distributed temperature profile can be obtained using a fiber optic sensor. The ability to energize electronics by means of an optical fiber has the advantage that electrical isolation is maintained at low cost. In order to accomplish this, it is necessary to convert the light energy into electrical form by means of photovoltaic cells. JPL has developed an array of PV cells in gallium arsenide specifically for this purpose. This work is described.

  10. Power system applications of fiber optic sensors

    Science.gov (United States)

    Johnston, A. R.; Jackson, S. P.; Kirkham, H.; Yeh, C.

    1986-01-01

    This document is a progress report of work done in 1985 on the Communications and Control for Electric Power Systems Project at the Jet Propulsion Laboratory. These topics are covered: Electric Field Measurement, Fiber Optic Temperature Sensing, and Optical Power transfer. Work was done on the measurement of ac and dc electric fields. A prototype sensor for measuring alternating fields was made using a very simple electroscope approach. An electronic field mill sensor for dc fields was made using a fiber optic readout, so that the entire probe could be operated isolated from ground. There are several instances in which more precise knowledge of the temperature of electrical power apparatus would be useful. This report describes a number of methods whereby the distributed temperature profile can be obtained using a fiber optic sensor. The ability to energize electronics by means of an optical fiber has the advantage that electrical isolation is maintained at low cost. In order to accomplish this, it is necessary to convert the light energy into electrical form by means of photovoltaic cells. JPL has developed an array of PV cells in gallium arsenide specifically for this purpose. This work is described.

  11. Fiber Ring Optical Gyroscope (FROG)

    Science.gov (United States)

    1979-01-01

    The design, construction, and testing of a one meter diameter fiber ring optical gyro, using 1.57 kilometers of single mode fiber, are described. The various noise components: electronic, thermal, mechanical, and optical, were evaluated. Both dc and ac methods were used. An attempt was made to measure the Earth rotation rate; however, the results were questionable because of the optical and electronic noise present. It was concluded that fiber ring optical gyroscopes using all discrete components have many serious problems that can only be overcome by discarding the discrete approach and adapting an all integrated optic technique that has the laser source, modulator, detector, beamsplitters, and bias element on a single chip.

  12. Optimize Etching Based Single Mode Fiber Optic Temperature Sensor

    Directory of Open Access Journals (Sweden)

    Ajay Kumar

    2014-02-01

    Full Text Available This paper presents a description of etching process for fabrication single mode optical fiber sensors. The process of fabrication demonstrates an optimized etching based method to fabricate single mode fiber (SMF optic sensors in specified constant time and temperature. We propose a single mode optical fiber based temperature sensor, where the temperature sensing region is obtained by etching its cladding diameter over small length to a critical value. It is observed that the light transmission through etched fiber at 1550 nm wavelength optical source becomes highly temperature sensitive, compared to the temperature insensitive behavior observed in un-etched fiber for the range on 30ºC to 100ºC at 1550 nm. The sensor response under temperature cycling is repeatable and, proposed to be useful for low frequency analogue signal transmission over optical fiber by means of inline thermal modulation approach.

  13. Achromatic optical diode in fiber optics

    CERN Document Server

    Berent, Michal; Vitanov, Nikolay V

    2013-01-01

    We propose a broadband optical diode, which is composed of one achromatic reciprocal quarter-wave plate and one non-reciprocal quarter-wave plate, both placed between two crossed polarizers. The presented design of achromatic wave plates relies on an adiabatic evolution of the Stokes vector, thus, the scheme is robust and efficient. The possible simple implementation using fiber optics is suggested.

  14. Structure state detection and damage assessment system with fiber optic sensing array and neural network signal processing techniques

    Science.gov (United States)

    Tu, Yaqing; Huang, Shanglian; Chen, Weimin; Tang, Jun

    1994-08-01

    The principle and structure of a structure state detection and damage assessment system are given. A novel fiberoptic sensing array and suitable neural network signal processing techniques are described. The experimental results on structural member of gypsum show that the system can monitor physical states of structures and can be developed into smart structures with potential applications in areas such as space aeronautics, ship and civil engineering, etc.

  15. Utilization of Infrared Fiber Optic in the Automotive Industry

    Science.gov (United States)

    Tucker, Dennis S.; Brantley, Lott W. (Technical Monitor)

    2001-01-01

    Fiber optics are finding a place in the automotive industry. Illumination is the primary application today. Soon, however, fiber optics will be used for data communications and sensing applications. Silica fiber optics and plastic fibers are sufficient for illumination and communication applications however, sensing applications involving high temperature measurement and remote gas analysis would benefit from the use of infrared fiber optics. Chalcogonide and heavy metal fluoride glass optical fibers are two good candidates for these applications. Heavy metal fluoride optical fibers are being investigated by NASA for applications requiring transmission in the infrared portion of the electromagnetic spectrum. Zirconium-Barium-Lanthanum-Aluminum-Sodium-Fluoride (ZBLAN) is one such material which has been investigated. This material has a theoretical attenuation coefficient 100 times lower than that of silica and transmits into the mid-IR. However, the measured attenuation coefficient is higher than silica due to impurities and crystallization. Impurities can be taken care of by utilizing cleaner experimental protocol. It has been found that crystallization can be suppressed by processing in reduced gravity. Fibers processed in reduced gravity on the KC135 reduced gravity aircraft were found to be free of crystals while those processed on the ground were found to have crystals. These results will be presented along with plans for producing continuous lengths of ZBLAN optical fiber on board the International Space Station.

  16. Robust Mapping of Incoherent Fiber-Optic Bundles

    Science.gov (United States)

    Roberts, Harry E.; Deason, Brent E.; DePlachett, Charles P.; Pilgrim, Robert A.; Sanford, Harold S.

    2007-01-01

    A method and apparatus for mapping between the positions of fibers at opposite ends of incoherent fiber-optic bundles have been invented to enable the use of such bundles to transmit images in visible or infrared light. The method is robust in the sense that it provides useful mapping even for a bundle that contains thousands of narrow, irregularly packed fibers, some of which may be defective. In a coherent fiber-optic bundle, the input and output ends of each fiber lie at identical positions in the input and output planes; therefore, the bundle can be used to transmit images without further modification. Unfortunately, the fabrication of coherent fiber-optic bundles is too labor-intensive and expensive for many applications. An incoherent fiber-optic bundle can be fabricated more easily and at lower cost, but it produces a scrambled image because the position of the end of each fiber in the input plane is generally different from the end of the same fiber in the output plane. However, the image transmitted by an incoherent fiber-optic bundle can be unscrambled (or, from a different perspective, decoded) by digital processing of the output image if the mapping between the input and output fiber-end positions is known. Thus, the present invention enables the use of relatively inexpensive fiber-optic bundles to transmit images.

  17. Multifunctional optical system-on-a-chip for heterogeneous fiber optic sensor networks

    Science.gov (United States)

    Yu, Miao; Pang, Cheng; Gupta, Ashwani

    2015-08-01

    In this article, we review our recent progress on the development of a multifunctional optical system-on-a-chip platform, which can be used for achieving heterogeneous wireless fiber optical sensor networks. A multifunctional optical sensor platform based on the micro-electromechanical systems (MEMS) technology is developed. The key component of the multifunctional optical sensor platform is a MEMS based tunable Fabry-Pérot (FP) filter, which can be used as a phase modulator or a wavelength tuning device in a multifunctional optical sensing system. Mechanics model of the FP filter and optics model of the multifunctional optical sensing system are developed to facilitate the design of the filter. The MEMS FP filter is implemented in a multifunctional optical sensing system including both Fabry-Perot interferometer based sensors and Fiber Bragg grating sensors. The experimental results indicate that this large dynamic range tunable filter can enable high performance heterogeneous optical sensing for many applications.

  18. Monolithic fiber optic sensor assembly

    Science.gov (United States)

    Sanders, Scott

    2015-02-10

    A remote sensor element for spectrographic measurements employs a monolithic assembly of one or two fiber optics to two optical elements separated by a supporting structure to allow the flow of gases or particulates therebetween. In a preferred embodiment, the sensor element components are fused ceramic to resist high temperatures and failure from large temperature changes.

  19. Implementation of a High-Speed FPGA and DSP Based FFT Processor for Improving Strain Demodulation Performance in a Fiber-Optic-Based Sensing System

    Science.gov (United States)

    Farley, Douglas L.

    2005-01-01

    NASA's Aviation Safety and Security Program is pursuing research in on-board Structural Health Management (SHM) technologies for purposes of reducing or eliminating aircraft accidents due to system and component failures. Under this program, NASA Langley Research Center (LaRC) is developing a strain-based structural health-monitoring concept that incorporates a fiber optic-based measuring system for acquiring strain values. This fiber optic-based measuring system provides for the distribution of thousands of strain sensors embedded in a network of fiber optic cables. The resolution of strain value at each discrete sensor point requires a computationally demanding data reduction software process that, when hosted on a conventional processor, is not suitable for near real-time measurement. This report describes the development and integration of an alternative computing environment using dedicated computing hardware for performing the data reduction. Performance comparison between the existing and the hardware-based system is presented.

  20. Towards biochips using microstructured optical fiber sensors

    DEFF Research Database (Denmark)

    Rindorf, Lars Henning; Hoiby, Poul Erik

    2006-01-01

    In this paper we present the first incorporation of a microstructured optical fiber (MOF) into biochip applications. A 16-mm-long piece of MOF is incorporated into an optic-fluidic coupler chip, which is fabricated in PMMA polymer using a CO2 laser. The developed chip configuration allows the continuous control of liquid flow through the MOF and simultaneous optical characterization. While integrated in the chip, the MOF is functionalized towards the capture of a specific single-stranded DNA string by immobilizing a sensing layer on the microstructured internal surfaces of the fiber. The sensing layer contains the DNA string complementary to the target DNA sequence and thus operates through the highly selective DNA hybridization process. Optical detection of the captured DNA was carried out using the evanescent-wave-sensing principle. Owing to the small size of the chip, the presented technique allows for analysis of sample volumes down to 300 nL and the fabrication of miniaturized portable devices.

  1. Fiber optic fire detection technology

    International Nuclear Information System (INIS)

    Electrostatic application of paint was, and still is, the most technically feasible method of reducing VOC (volatile organic compounds) emissions, while reducing the cost to apply the coatings. Prior to the use of electrostatics, only two sides of the traditional fire triangle were normally present in the booth, fuel (solvent), and oxygen (air). Now the third leg (the ignition source) was present at virtually all times during the production operation in the form of the electrostatic charge and the resulting energy in the system. The introduction of fiber optics into the field of fire detection was for specific application to the electrostatic painting industry, but specifically, robots used in the application of electrostatic painting in the automotive industry. The use of fiber optics in this hazard provided detection for locations that have been previously prohibited or inaccessible with the traditional fire detection systems. The fiber optic technology that has been adapted to the field of fire detection operates on the principle of transmission of photons through a light guide (optic fiber). When the light guide is subjected to heat, the cladding on the light guide melts away from the core and allows the light (photons) to escape. The controller, which contains the emitter and receiver is set-up to distinguish between partial loss of light and a total loss of light. Glass optical fibers carrying light offer distinct advantages over wires or coaxial cables carrying electricity as a transmission media. The uses of fiber optic detection will be expanded in the near future into such areas as aircraft, cable trays and long conveyor runs because fiber optics can carry more information and deliver it with greater clarity over longer distances with total immunity to all kinds of electrical interference

  2. SPS fiber optic link assessment

    Science.gov (United States)

    Lindsay, T. O.; Nalos, E. J.

    1980-01-01

    Fiber optic technology was selected in the SPS baseline design to transmit a stable phase reference throughout the microwave array. Over a hundred thousand microwave modules are electronically steered by the phase reference signal to form the power beam at the ground receiving station. The initially selected IF distribution frequency of the phase reference signal was set at 980 MHz or a submultiple of it. Fiber optics offers some significant advantages in view of the SPS application. Optical transmission is highly immume to EMI/RFI, which is expected to be severe when considering the low distribution power. In addition, there will be savings in both mass, physical size, and potentially in cost.

  3. U-optrode-based fiber optic thermometers

    Science.gov (United States)

    Kalvoda, Ladislav; Aubrecht, Jan; Klepá?ek, Rudolf; Lukášová, Petra

    2011-05-01

    Extremely bent optical fiber (U-optrode) is applicable as a sensing head, signal of which is govern by refractive index and light scattering properties of the surrounding medium. The presented contribution aims to shows that when covered with properly selected polymeric transducers, the reliable and fast thermometers covering different temperature ranges can be constructed suitable for, e.g., measurements in environments with high level of electric or magnetic disturbances. Obviously, the bare optrodes can be also used as sensitive analytic tools for collecting information about thermallyinduced changes of optical and micro-structural properties of polymers.

  4. Fiber optic chemical sensors: The evolution of high- density fiber-optic DNA microarrays

    Science.gov (United States)

    Ferguson, Jane A.

    2001-06-01

    Sensors were developed for multianalyte monitoring, fermentation monitoring, lactate analysis, remote oxygen detection for use in bioremediation monitoring and in a fuel spill clean-up project, heavy metal analysis, and high density DNA microarrays. The major focus of this thesis involved creating and improving high-density DNA gene arrays. Fiber optic sensors are created using fluorescent indicators, polymeric supports, and optical fiber substrates. The fluorescent indicator is entrapped in a polymer layer and attached to the tip of the optical fiber. The tip of the fiber bearing the sensing layer (the distal end) is placed in the sample of interest while the other end of the fiber (the proximal end) is connected to an analysis system. Any length of fiber can be used without compromising the integrity or sensitivity of the system. A fiber optic oxygen sensor was designed incorporating an oxygen sensitive fluorescent dye and a gas permeable polymer attached to an optical fiber. The construction simplicity and ruggedness of the sensor enabled its deployment for in situ chemical oxidation and bioremediation studies. Optical fibers were also used as the substrate to detect biomolecules in solution. To monitor bioprocesses, the production of the analyte of interest must be coupled with a species that is optically measurable. For example, oxygen is consumed in many metabolic functions. The fiber optic oxygen sensor is equipped with an additional sensing layer. Upon contact with a specific biochemical in the sample, a reaction occurs in the additional sensing layer that either consumes or produces oxygen. This dual layer system was used to monitor the presence of lactate, an important metabolite for clinical and bioprocess analysis. In many biological and environmental systems, the generation of one species occurs coincidentally with the generation or consumption of another species. A multianalyte sensor was prepared that can monitor the simultaneous activity of pH, CO2 and O2. This sensor is useful for monitoring bioprocesses such as (beer) fermentation and for clinical situations such as blood gas analysis. DNA sensors were created by attaching short single strands of DNA (probes) to the fiber tip. A matching single strand (target) forms a strong interacting pair with the probe upon contact. The target strands in a sample are labeled with a fluorescent dye. When a probe-target pair is formed and excitation light is sent down the fiber, the fiber bearing the pair emits light that is captured and detected. A high density DNA array was created by isolating thousands of discrete DNA sensors on the tip of an imaging optical fiber. This array was made possible by the formation of microwells on the imaging fiber tip. Microspheres functionalized with DNA were placed in the wells of the fiber and each microsphere was independently and simultaneously monitored. (Abstract shortened by UMI.)

  5. Fiber-diffraction Interferometer using Coherent Fiber Optic Taper

    OpenAIRE

    Kihm, Hagyong; Lee, Yun-Woo

    2010-01-01

    We present a fiber-diffraction interferometer using a coherent fiber optic taper for optical testing in an uncontrolled environment. We use a coherent fiber optic taper and a single-mode fiber having thermally-expanded core. Part of the measurement wave coming from a test target is condensed through a fiber optic taper and spatially filtered from a single-mode fiber to be reference wave. Vibration of the cavity between the target and the interferometer probe is common to both reference and me...

  6. Optical fiber based radial polarizer

    Science.gov (United States)

    Elbaz, David; Buhbut, Sophia; Kupfer, Benjamin Zeev; Zaban, Arie; Zalevsky, Zeev

    2012-05-01

    In this paper we present a new type of optical fiber aiming to radially polarize the electrical field. This special device is composed of a tapered fiber having a classical core while on top of its external surface, radially oriented nanorods are disposed. The tails of the propagated wave are interacting with those radially oriented nanorods. This interaction performs the polarization of the propagated mode into a radial polarization.

  7. Scintillating optical fibers in mammography

    International Nuclear Information System (INIS)

    Measurements of the MTF and the DQE, on images obtained using a scintillating glass optical fiber system coupled to a mammography film, are displayed in comparison with the measurements obtained by a standard mammography cassette using the same film and the same X-ray dose. The final results are favourable to the scintillating fibers. The use of a CCD read-out in the place of the mammography film is discussed. (orig.)

  8. Building polymer fiber optic network

    Science.gov (United States)

    Bienias, P.; Bere?-Pawlik, E.

    2015-09-01

    The paper describes an investigation of transmission in LAN with using polymer optical fiber (POF). There were used two kinds of POF, step index plastic optical fiber (SI-POF) and graded index plastic optical fiber (GI-POF). Furthermore, the paper include a comparison between SI-POF and GI-POF and possibilities of using them. For the project's needs, new type of couplers has been designed and built, optimization has been performed to obtain the best parameters for designed couplers. Additionally, the coupler has been built from the same material, which GI-POF - PMMA is made of. Moreover, CWDM (Coarse Wavelength Division Multiplexing) transmissions is investigated to improve the network capacity.

  9. Integrated optics for fiber gyro's

    Science.gov (United States)

    Goss, W.; Goldstein, R.

    1983-01-01

    Expected advantages of incorporating integrated optical waveguide components into fiber gyroscopes are summarized. The structural-simplicity benefits which can be achieved through the use of solid-state lasers, and integrated and fiber optics are examined; angular rate noise and random walk drift for the current technology in the 0.84-micron wavelength region are reported as 0.00001 deg/sec and 0.0002 deg/hr to the 1/2, respectively. The state-of-the-art in the pertinent materials research is reviewed; lithium niobate, suggested to be used as a waveguide substrate material, is noted to have a complex chemistry that is not yet fully understood. However, most of the optical and electrooptical components of a fiber gyro are conceptually understood and have been demonstrated.

  10. Modeling Climate Change and Thermal Restoration Strategies in a Northern California Stream Using HEAT SOURCE and Distributed Temperature Sensing Fiber-optics

    Science.gov (United States)

    Bond, R. M.; Stubblefield, A. P.

    2013-12-01

    Land uses which modify stream channel structure and riparian vegetation can alter the mechanisms of heat transfer within a stream. Stream temperature is a crucial abiotic factor which governs aquatic biota quantity, distribution, and overall health. The IPCC has projected stream temperature to increase with changes in global climate due to elevated air temperature and changes in precipitation patterns. Stream temperature modeling can investigate current and future stream temperature conditions. Heat Source, developed by Oregon Department of Environmental Quality (DEQ), was applied to a one kilometer section of the North Fork of the Salmon River, a tributary of the Klamath River, northern California, USA. Heat Source accounts for internal and external thermal energy transfers to predict stream temperature at point locations. Inputs include meteorologic, geomorphologic, hydrologic and topographic measurements from the study site. The Salmon River watershed has a legacy of historic hydraulic gold mining which has changed channel morphology and created extensive denuded gravel bars. The Salmon River is listed as thermally impaired under California's List of Impaired Water Bodies 303(d) with mainstem temperature commonly exceeding salmonid temperature thresholds. The objective of this research was to utilize Heat Source to predict effects of climate change, riparian management, and channel geometry on stream temperature. This study employed Distributed Temperature Sensing fiber-optics (DTS) to detect stream heating and cooling at one meter resolution which was then used to calibrate Heat Source at the study reach. Predicted values closely matched DTS measurements reflecting shifting responses to air temperature, riparian vegetation distribution, and channel geometry conditions. Heat Source modeling of climate change scenarios using forecasted 2049 and 2099 elevated air temperatures are presented. Furthermore, temperature impacts of increased riparian vegetation density and stream channelization were investigated as possible thermal restoration strategies to buffer streams from elevated temperatures resulting from climate change.

  11. Fiber Optic Temperature Sensor Based on Multimode Interference Effects

    International Nuclear Information System (INIS)

    A novel fiber optic temperature sensor based on multimode interference was designed, fabricated and tested. The sensor is very simple and inexpensive since we only need to splice a section of multimode fiber between two single mode fibers. Using this device a sensing range of 25 deg. C to 375 deg. C is demonstrated. We should also highlight that due to the pass-band filter response of MMI devices, multiplexing is rather simple by just changing the length of the multimode section.

  12. A fiber-optic current sensor for aerospace applications

    International Nuclear Information System (INIS)

    A robust, accurate, broad-band, alternating current sensor using fiber optics is being developed for space applications at power frequencies as high as 20 kHz. It can also be used in low and high voltage 60 Hz terrestrial power systems and in 400 Hz aircraft systems. It is intrinsically EMI immune and has the added benefit of excellent isolation. The sensor uses the Faraday effect in optical fiber and standard polarimetric measurements to sense electrical current. The primary component of the sensor is a specially treated coil of single-mode optical fiber, through which the current carrying conductor passes. Improved precision is accomplished by temperature compensation by means of signals from a novel fiber-optic temperature sensor embedded in the sensing head. This paper reports on the technology contained in the sensor and also relates the results of precision tests conducted at various temperatures within the wide operating range. It also shows the results of early EMI tests

  13. A fiber-optic current sensor for aerospace applications

    Science.gov (United States)

    Patterson, Richard L.; Rose, A. H.; Tang, D.; Day, G. W.

    1990-01-01

    A robust, accurate, broadband, alternating current sensor using fiber optics is being developed for space applications at power frequencies as high as 20 kHz. It can also be used in low and high voltage 60-Hz terrestrial power systems and in 400-Hz aircraft systems. It is intrinsically electromagnetic interference (EMI) immune and has the added benefit of excellent isolation. The sensor uses the Faraday effect in optical fiber and standard polarimetric measurements to sense electrical current. The primary component of the sensor is a specially treated coil of single-mode optical fiber, through which the current carrying conductor passes. Improved precision is accomplished by temperature compensation by means of signals from a novel fiber-optic temperature sensor embedded in the sensing head. The technology used in the sensor is examined and the results of precision tests conducted at various temperatures within the wide operating range are given. The results of early EMI tests are also given.

  14. Novel optical microresonators for sensing applications

    Science.gov (United States)

    Wang, Hanzheng

    Optical microresonators have been proven as an effective means for sensing applications. The high quality (Q) optical whispering gallery modes (WGMs) circulating around the rotationally symmetric structures can interact with the local environment through the evanescent field. The high sensitivity in detection was achieved by the long photon lifetime of the high-Q resonator (thus the long light-environment interaction path). The environmental variation near the resonator surface leads to the effective refractive index change and thus a shift at the resonance wavelength. In this dissertation, we present our recent research on the development of new optical microresonators for sensing applications. Different structures and materials are used to develop optical resonator for broad sensing applications. Specifically, a new coupling method is designed and demonstrated for efficient excitation of microsphere resonators. The new coupler is made by fusion splicing an optical fiber with a capillary tube and consequently etching the capillary wall to a thickness of a few microns. Light is coupled through the peripheral contact between inserted microsphere and the etched capillary wall. Operating in the reflection mode and providing a robust mechanical support to the microresonator, the integrated structure has been experimentally proven as a convenient probe for sensing applications. Microspheres made of different materials (e.g., PMMA, porous glass, hollow core porous, and glass solid borosilicate glass) were successfully demonstrated for different sensing purposes, including temperature, chemical vapor concentration, and glucose concentration in aqueous solutions. In addition, the alignment free, integrated microresonator structure may also find other applications such as optical filters and microcavity lasers.

  15. Longitudinal strain sensing with photonic crystal fibers and fiber Bragg gratings

    Science.gov (United States)

    Tenderenda, T.; Murawski, M.; Szymanski, M.; Szostkiewicz, L.; Becker, M.; Rothhardt, M.; Bartelt, H.; Mergo, P.; Poturaj, Kl; Makara, M.; Skorupski, K.; Marc, P.; Jaroszewicz, L. R.; Nasilowski, T.

    2014-03-01

    Photonic crystal fibers (PCF), sometimes also referred to as microstructured fibers (MSF), have been a subject of extensive research for over a decade. This is mainly due to the fact that by changing the geometry and distribution of the air holes the fiber properties can be significantly modified and tailored to specific applications. In this paper we present the results of a numerical analysis of the influence of the air-hole distribution on the sensitivity of the propagated modes' effective refractive index to externally applied longitudinal strain. We propose an optimal strain sensitive fiber design, with a number of fibers drawn and experimentally evaluated to confirm the theoretical results. Furthermore as the direct measurement of the effective refractive index change may be complex and challenging in field environment, we propose to use fiber Bragg gratings (FBG) in our sensing set-up. As the Bragg wavelength is a function of the effective refractive index, the external strain changes can be monitored through the Bragg wavelength shift with a simple optical spectrometer. Moreover, since the PCF is also optimized for low-loss splicing with standard single mode fiber, our novel sensor head can be used with standard off-the-shelf components in complex multiplexed sensing arrays, with the measured signal transmitted to and from the sensor head by standard telecom fibers, which significantly reduces costs.

  16. Fiber optics principles and practices

    CERN Document Server

    Al-Azzawi, Abdul

    2007-01-01

    Since the invention of the laser, our fascination with the photon has led to one of the most dynamic and rapidly growing fields of technology. New advances in fiber optic devices, components, and materials make it more important than ever to stay current. Comprising chapters drawn from the author's highly anticipated book Photonics: Principles and Practices, Fiber Optics: Principles and Practices offers a detailed and focused treatment for anyone in need of authoritative information on this critical area underlying photonics.Using a consistent approach, the author leads you step-by-step throug

  17. A Novel Design of Grooved Fibers for Fiber-Optic Localized Plasmon Resonance Biosensors

    Directory of Open Access Journals (Sweden)

    Lai-Kwan Chau

    2009-08-01

    Full Text Available Bio-molecular recognition is detected by the unique optical properties of self-assembled gold nanoparticles on the unclad portions of an optical fiber whose surfaces have been modified with a receptor. To enhance the performance of the sensing platform, the sensing element is integrated with a microfluidic chip to reduce sample and reagent volume, to shorten response time and analysis time, as well as to increase sensitivity. The main purpose of the present study is to design grooves on the optical fiber for the FO-LPR microfluidic chip and investigate the effect of the groove geometry on the biochemical binding kinetics through simulations. The optical fiber is designed and termed as U-type or D-type based on the shape of the grooves. The numerical results indicate that the design of the D-type fiber exhibits efficient performance on biochemical binding. The grooves designed on the optical fiber also induce chaotic advection to enhance the mixing in the microchannel. The mixing patterns indicate that D-type grooves enhance the mixing more effectively than U-type grooves. D-type fiber with six grooves is the optimum design according to the numerical results. The experimental results show that the D-type fiber could sustain larger elongation than the U-type fiber. Furthermore, this study successfully demonstrates the feasibility of fabricating the grooved optical fibers by the femtosecond laser, and making a transmission-based FO-LPR probe for chemical sensing. The sensor resolution of the sensor implementing the D-type fiber modified by gold nanoparticles was 4.1 × 10-7 RIU, which is much more sensitive than that of U-type optical fiber (1.8 × 10-3 RIU.

  18. Fiber optic switch concept with analog micromirror device

    Science.gov (United States)

    Lausch, Christine; Goering, Rolf; Wippermann, Frank

    2003-01-01

    A novelle concept for miniaturized multimode fiber optical switches is presented, which can be applied for the whole spectrum of fiber core diameter and numerical aperture. It is particularly useful for large core high numerical aperture fibers used for applications in illumination systems, sensing and optical spectrometers. Because of relaxed positioning tolerances - compared to singlemode setups - most existing solutions are based on moving fibers or fiber collimators leading to devices with excellent optical parameters. Due to the mechanical properties of the fibers it is difficult to use these switching principles for fibers with large diameter. The system we present is based on fixed fibers, each having a collimating lens. A following imaging system projects the incoming optical beam to a tilting high-reflectivity micromirror placed in the focal plane. The reflected beam travels back through the imaging system targeting an output fiber which is addressed by the angle position of the mirror. Due to the folded optics design both input and output channels are located on the same side of the device. Special emphasis was taken on the chromatic dispersion behaviour of the setup leading to a broad spectral range. We present the optical and mechanical design considerations and experimental results obtained with first realized prototypes of 1×4 and 1×8 style switches for 400?m core diameter multimode fibers.

  19. Handbook of fiber optics theory and applications

    CERN Document Server

    Yeh, Chai

    2013-01-01

    Dr. Yeh supplies a firm theoretical foundation in such topics as propagation of light through fibers, fiber fabrication, loss mechanisms, and dispersion properties. He then expands from this into such practical areas as fiber splicing, measuring loss in fibers, fiber-based communications networks, remote fiber sensors, and integrated optics. Whether involved in fiber optics research, design, or practical implementation of systems, this handbook will be extremely useful.Key Features* Here is a comprehensive, ""one-stop"" reference with state-of-the-art information on fiber optics Included is da

  20. Subwavelength and nanometer diameter optical fibers

    CERN Document Server

    Tong, Limin

    2011-01-01

    Subwavelength and Nanometer Diameter Optical Fibers provides a comprehensive and up-to-date coverage of research on nanoscale optical fibers including the basic physics and engineering aspects of the fabrication, properties and applications. The book discusses optical micro/nanofibers that represent a perfect fusion of optical fibers and nanotechnology on subwavelength scale and covers a broad range of topics in modern optical engineering, photonics and nanotechnology spanning from fiber optics, near-field optics, nonlinear optics, atom optics to nanofabrication and microphotonic components/de

  1. Enhancing Optical Communications with Brand New Fibers

    DEFF Research Database (Denmark)

    Morioka, Toshio; Awaji, Yoshinari; Ryf, Roland; Winzer, Peter; Richardson, David; Poletti, Francesco

    2012-01-01

    Optical fibers have often been considered to offer effectively infinite capacity to support the rapid traffic growth essential to our information society. However, as demand has grown and technology has developed, we have begun to realize that there is a fundamental limit to fiber capacity of ~ 100...... Tb/s per fiber for systems based on conventional single-core single-mode optical fiber as the transmission medium. This limit arises from the interplay of a number of factors including the Shannon limit, optical fiber nonlinearities, the fiber fuse effect, as well as optical amplifier bandwidth. This...... new fibers for space-division multiplexing and mode-division multiplexing....

  2. Feasibility of soil moisture monitoring with heated fiber optics :

    OpenAIRE

    Sayde, C.; Gregory, C.; Gil-Rodriguez, M.; Tufillaro, N.; Tyler, S; van de Giesen, N.C.; English, M.; Cuenca, R.; Selker, J.S.

    2010-01-01

    Accurate methods are needed to measure changing soil water content from meter to kilometer scales. Laboratory results demonstrate the feasibility of the heat pulse method implemented with fiber optic temperature sensing to obtain accurate distributed measurements of soil water content. A fiber optic cable with an electrically conductive armoring was buried in variably saturated sand and heated via electrical resistance to create thermal pulses monitored by observing the distributed Raman back...

  3. Fundamental study on the development of fiber optic sensor for real-time sensing of CaCO3 scale formation in geothermal water.

    Science.gov (United States)

    Okazaki, Takuya; Imai, Kenichiro; Tan, Shin Y; Yong, Yun T; Rahman, Faidz A; Hata, Noriko; Taguchi, Shigeru; Ueda, Akira; Kuramitz, Hideki

    2015-01-01

    This study proposes an optical fiber sensor for calcium carbonate (CaCO3) scale formation in water. The sensor is easily fabricated by removing the cladding of a multimode fiber to expose the core towards the surrounding medium in order to detect refractive index change. A variation of the transmittance response from the high refractive index of CaCO3 which precipitated on the fiber core surface was observed. The proposed setup can be used to analyze the transmittance response over wide range of wavelength using white light as a source and also a spectroscopy detector. The curve of the transmittance percentage over time showed that a fiber core with 200 ?m has higher sensitivity as compared to a fiber core with 400 ?m. The findings from this study showed that the sensor detection region at near infrared (NIR) wavelengths showed better sensitivity than visible light (VIS) wavelengths. Field tests were conducted using natural geothermal water at Matsushiro, Japan in order to verify the performance of the proposed sensor. The optical response was successfully evaluated and the analytical results confirmed the capability of monitoring scale formation in a geothermal water environment. PMID:25765379

  4. Fiber optic interferometer with digital heterodyne detection using lithiumniobate devices

    International Nuclear Information System (INIS)

    Fiber optic interferometers with single mode fibers provide high sensitivity for sensing e.g. temperature, sound, electric and magnetic fields. The inclusion of integrated optic components into the interferometer implements important functions such as splitting, recombining, phase compensation, polarization control in a compact way. Above all, integrated optic devices allow efficient heterodyne detection schemes with a linear conversion of the sensor phase ? and the sensor transmission H into corresponding electrical signals. electro-optic LiNbO3 devices are particularly attractive for these purposes. Here, the authors report on fiber optic Michelson and Mach-Zehnder interferometers which are built-up with polarization maintaining fibers and integrated optic LiNbO3 devices. A digital heterodyne detection with a high dynamic range (up to 60 dB) is accomplished by a proper digital phase modulation. A basic configuration is depicted

  5. Drift reduction in an optical heterodyne fiber gyro.

    Science.gov (United States)

    Hotate, K; Samukawa, S

    1990-03-20

    An optical heterodyne fiber gyro, which we recently proposed, is improved to reduce the zero-point drift. A reference interferometer is introduced in the improved configuration beside the sensing interferometer to obtain the Sagnac phase shift, which monitors the drift caused in the optical system. Experimental results demonstrate successful reduction of the drift. PMID:20563004

  6. Polymer optical fiber sensors—a review

    International Nuclear Information System (INIS)

    Polymer optical fibers (POFs) have significant advantages for many sensing applications, including high elastic strain limits, high fracture toughness, high flexibility in bending, high sensitivity to strain and potential negative thermo-optic coefficients. The recent emergence of single-mode POFs has enabled high precision, large deformation optical fiber sensors. This article describes recent advances in both multi-mode and single-mode POF based strain and temperature sensors. The mechanical and optical properties of POFs relevant to strain and temperature applications are first summarized. POFs considered include multi-mode POFs, solid core single-mode POFs and microstructured single-mode POFs. Practical methods for applying POF sensors, including connecting and embedding sensors in structural materials, are also described. Recent demonstrations of multi-mode POF sensors in structural applications based on new interrogation methods, including backscattering and time-of-flight measurements, are outlined. The phase–displacement relation of a single-mode POF undergoing large deformation is presented to build a fundamental understanding of the response of single-mode POF sensors. Finally, this article highlights recent single-mode POF based sensors based on polymer fiber Bragg gratings and microstructured POFs. (topical review)

  7. Fiber Optic Vibration Sensor Based on the Tilted Fiber Bragg Grating

    OpenAIRE

    Jiali An; Tao Liu; Yongxing Jin

    2013-01-01

    A temperature-insensitive fiber optic vibration sensor based on the tilted fiber Bragg grating (TFBG) is presented. The sensing head is formed by insertion of a small section of MMF between a single-mode fiber and the TFBG. The reflection light from this tilted fiber Bragg grating includes two parts: the reflected Bragg mode and the cladding modes. The cladding modes were coupled back into the core mode as a function of the multimode fiber. The power of the cladding modes is sensitive to vibr...

  8. Feasibility of giant fiber-optic gyroscopes

    OpenAIRE

    Schiller, Stephan

    2013-01-01

    The availability of long-distance, underground fiber-optic links opens a perspective of implementing interferometric fiber-optic gyroscopes embracing very large areas. We discuss the potential sensitivity, some disturbances and approaches to overcome them.

  9. Fiber-Optic Continuous Liquid Sensor for Cryogenic Propellant Gauging

    Science.gov (United States)

    Xu. Wei

    2010-01-01

    An innovative fiber-optic sensor has been developed for low-thrust-level settled mass gauging with measurement uncertainty optical fiber to measure liquid level and liquid distribution of cryogenic propellants. Every point of the sensing fiber is a point sensor that not only distinguishes liquid and vapor, but also measures temperature. This sensor is able to determine the physical location of each point sensor with 1-mm spatial resolution. Acting as a continuous array of numerous liquid/vapor point sensors, the truly distributed optical sensing fiber can be installed in a propellant tank in the same manner as silicon diode point sensor stripes using only a single feedthrough to connect to an optical signal interrogation unit outside the tank. Either water or liquid nitrogen levels can be measured within 1-mm spatial resolution up to a distance of 70 meters from the optical interrogation unit. This liquid-level sensing technique was also compared to the pressure gauge measurement technique in water and liquid nitrogen contained in a vertical copper pipe with a reasonable degree of accuracy. It has been demonstrated that the sensor can measure liquid levels in multiple containers containing water or liquid nitrogen with one signal interrogation unit. The liquid levels measured by the multiple fiber sensors were consistent with those virtually measured by a ruler. The sensing performance of various optical fibers has been measured, and has demonstrated that they can survive after immersion at cryogenic temperatures. The fiber strength in liquid nitrogen has also been measured. Multiple water level tests were also conducted under various actual and theoretical vibration conditions, and demonstrated that the signal-to-noise ratio under these vibration conditions, insofar as it affects measurement accuracy, is manageable and robust enough for a wide variety of spacecraft applications. A simple solution has been developed to absorb optical energy at the termination of the optical sensor, thereby avoiding any feedback to the optical interrogation unit

  10. Recent progress in distributed fiber optic sensors.

    Science.gov (United States)

    Bao, Xiaoyi; Chen, Liang

    2012-01-01

    Rayleigh, Brillouin and Raman scatterings in fibers result from the interaction of photons with local material characteristic features like density, temperature and strain. For example an acoustic/mechanical wave generates a dynamic density variation; such a variation may be affected by local temperature, strain, vibration and birefringence. By detecting changes in the amplitude, frequency and phase of light scattered along a fiber, one can realize a distributed fiber sensor for measuring localized temperature, strain, vibration and birefringence over lengths ranging from meters to one hundred kilometers. Such a measurement can be made in the time domain or frequency domain to resolve location information. With coherent detection of the scattered light one can observe changes in birefringence and beat length for fibers and devices. The progress on state of the art technology for sensing performance, in terms of spatial resolution and limitations on sensing length is reviewed. These distributed sensors can be used for disaster prevention in the civil structural monitoring of pipelines, bridges, dams and railroads. A sensor with centimeter spatial resolution and high precision measurement of temperature, strain, vibration and birefringence can find applications in aerospace smart structures, material processing, and the characterization of optical materials and devices. PMID:23012508

  11. Recent Progress in Distributed Fiber Optic Sensors

    Directory of Open Access Journals (Sweden)

    Xiaoyi Bao

    2012-06-01

    Full Text Available Rayleigh, Brillouin and Raman scatterings in fibers result from the interaction of photons with local material characteristic features like density, temperature and strain. For example an acoustic/mechanical wave generates a dynamic density variation; such a variation may be affected by local temperature, strain, vibration and birefringence. By detecting changes in the amplitude, frequency and phase of light scattered along a fiber, one can realize a distributed fiber sensor for measuring localized temperature, strain, vibration and birefringence over lengths ranging from meters to one hundred kilometers. Such a measurement can be made in the time domain or frequency domain to resolve location information. With coherent detection of the scattered light one can observe changes in birefringence and beat length for fibers and devices. The progress on state of the art technology for sensing performance, in terms of spatial resolution and limitations on sensing length is reviewed. These distributed sensors can be used for disaster prevention in the civil structural monitoring of pipelines, bridges, dams and railroads. A sensor with centimeter spatial resolution and high precision measurement of temperature, strain, vibration and birefringence can find applications in aerospace smart structures, material processing, and the characterization of optical materials and devices.

  12. Applications of fiber optics in physical protection

    Energy Technology Data Exchange (ETDEWEB)

    Buckle, T.H. [Sandia National Labs., Albuquerque, NM (United States)

    1994-03-01

    The purpose of this NUREG is to provide technical information useful for the development of fiber-optic communications and intrusion detection subsystems relevant to physical protection. There are major sections on fiber-optic technology and applications. Other topics include fiber-optic system components and systems engineering. This document also contains a glossary, a list of standards and specifications, and a list of fiber-optic equipment vendors.

  13. Engineering modes in optical fibers with metamaterial

    DEFF Research Database (Denmark)

    Yan, Min; Mortensen, Asger; Qiu, Min

    2009-01-01

    In this paper, we report a preliminary theoretical study on optical fibers with fine material inclusions whose geometrical inhomogeneity is almost indistinguishable by the operating wavelength.We refer to such fibers as metamaterial optical fibers, which can conceptually be considered as an extension from the previously much publicized microstructured optical fibers. Metamaterials can have optical properties not obtainable in naturally existing materials, including artificial anisotropy as well ...

  14. High pressure fiber optic sensor system

    Science.gov (United States)

    Guida, Renato; Xia, Hua; Lee, Boon K; Dekate, Sachin N

    2013-11-26

    The present application provides a fiber optic sensor system. The fiber optic sensor system may include a small diameter bellows, a large diameter bellows, and a fiber optic pressure sensor attached to the small diameter bellows. Contraction of the large diameter bellows under an applied pressure may cause the small diameter bellows to expand such that the fiber optic pressure sensor may measure the applied pressure.

  15. Applications of fiber optics in physical protection

    International Nuclear Information System (INIS)

    The purpose of this NUREG is to provide technical information useful for the development of fiber-optic communications and intrusion detection subsystems relevant to physical protection. There are major sections on fiber-optic technology and applications. Other topics include fiber-optic system components and systems engineering. This document also contains a glossary, a list of standards and specifications, and a list of fiber-optic equipment vendors

  16. Surface Plasmon Resonance-Based Fiber Optic Sensors: Principle, Probe Designs, and Some Applications

    OpenAIRE

    R.K. Verma; Gupta, B. D.

    2009-01-01

    Surface plasmon resonance technique in collaboration with optical fiber technology has brought tremendous advancements in sensing of various physical, chemical, and biochemical parameters. In this review article, we present the principle of SPR technique for sensing and various designs of the fiber optic SPR probe reported for the enhancement of the sensitivity of the sensor. In addition, we present few examples of the surface plasmon resonance- (SPR-) based fiber optic sensors. The present r...

  17. Silica glass optical fibers. Sekiei kei hikari fiber

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, K. (Furukawa Electric Co. Ltd., Tokyo (Japan). Yokohama Lab.)

    1990-07-05

    A report is made on the structure, materials, basic characteristics and method of production of silica glass optical fibers for optical communication already put to practical use, as well as on recent optical fiber having new structures. Silica fiber consists of the core and clad made of silica glass, and various kinds of silica glasses are used for making the fibers. Standard transmission characteristics, structural dimensions, applications, etc. of the silica glass optical fibers are shown. The manufacturing processes of silica glass optical fibers can be divided into base material production process and drawing process for making the base material in fiber form, and there are 4 types of manufacturing methods. Optical fiber whose zero dispersion wave length is transferred near 1.55 {mu} m is called a dispersion shift single mode optical fiber, which can be used for large capacity and long distance transmission. Entire fluroine doped shift single mode optical fiber and hermetically coated optical fiber whose water resistance and hydrogen resistance are markedly improved are also outlined. 4 refs., 5 figs., 2 tabs.

  18. Nonlinear fiber optics formerly quantum electronics

    CERN Document Server

    Agrawal, Govind

    1995-01-01

    The field of nonlinear fiber optics has grown substantially since the First Edition of Nonlinear Fiber Optics, published in 1989. Like the First Edition, this Second Edition is a comprehensive, tutorial, and up-to-date account of nonlinear optical phenomena in fiber optics. It synthesizes widely scattered research material and presents it in an accessible manner for students and researchers already engaged in or wishing to enter the field of nonlinear fiber optics. Particular attention is paid to the importance of nonlinear effects in the design of optical fiber communication systems. This is

  19. Optical fiber coatings for medical applications

    Science.gov (United States)

    Biswas, Dipak R.

    1992-08-01

    Fiber-optic based laser delivery systems are one of the most important applications of optical fibers in the medical industry. Silica optical fibers are becoming a standard vehicle for laser transport into the human body. Two types of silica core fibers with polymer cladding or glass cladding are being considered. Optical fiber coatings play an important role in fiber strength, reliability, and biocompatibility. Three major coatings, such as organic (polymeric), metallic, and inorganic, are commonly used on optical fibers. The polymeric coatings include ultraviolet-cured acrylate, silicone, and polyimide; metallic coatings include aluminum, indium, tin, and gold; inorganic coatings include oxides, carbides, nitrides, and carbon. In the medical industry, polymeric coatings are widely used. Metallic and inorganic coatings on optical fibers also can be considered. This paper highlights the strength, fatigue, and biocompatibility of silica fibers with different coatings.

  20. Crack monitoring capability of plastic optical fibers for concrete structures

    Science.gov (United States)

    Zhao, Jinlei; Bao, Tengfei; Chen, Rui

    2015-08-01

    Optical fibers have been widely used in structural health monitoring. Traditional silica fibers are easy to break in field applications due to their brittleness. Thus, silica fibers are proposed to be replaced by plastic optical fibers (POFs) in crack monitoring in this study. Moreover, considering the uncertainty of crack propagation direction in composite materials, the influence of the angles between fibers and cracks on the monitoring capability of plastic optical fibers is studied. A POF sensing device was designed and the relationship between light intensity loss and crack width under different fiber/crack angles was first measured through the device. Then, three-point bend tests were conducted on concrete beams. POFs were glued to the bottom surfaces of the beams and light intensity loss with crack width was measured. Experimental results showed that light intensity loss in plastic optical fibers increased with crack width increase. Therefore, application of plastic optical fibers in crack monitoring is feasible. Moreover, the results also showed that the sensitivity of the POF crack sensor decreased with the increase of angles between fibers and cracks.

  1. Career Directions--Fiber Optic Installer

    Science.gov (United States)

    Tech Directions, 2012

    2012-01-01

    Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of light through an optical fiber that is roughly the diameter of a human hair. The light forms an electromagnetic carrier wave that is modulated to carry information. Each optical fiber is capable of carrying an enormous amount of…

  2. Fiber-optical microphones and accelerometers based on polymer optical fiber Bragg gratings

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Stefani, Alessio; Bang, Ole; Jacobsen, Torben K.; Rose, Bjarke; Herholdt-Rasmussen, Nicolai; Nielsen, Finn Kryger; Andresen, Søren; Sørensen, Ole Brøsted; Hansen, Knud Styhr

    2010-01-01

    Polymer optical fibers (POFs) are ideal for applications as the sensing element in fiber-optical microphones and accelerometers based on fiber Bragg gratings (FBGs) due to their reduced Young’s Modulus of 3.2GPa, compared to 72GPa of Silica. To maximize the sensitivity and the dynamic range of the...... device the outer diameter and the length of the sensing fiber segment should be as small as possible. To this end we have fabricated 3mm FBGs in single-mode step-index POFs of diameter 115 micron, using 325nm UV writing and a phase-mask technique. 6mm POF sections with FBGs in the center have been glued...... to standard Silica SMF28 fibers. These POF FBGs have been characterized in terms of temperature and strain to find operating regimes with no hysteresis. Commercial fast wavelength interrogators (KHz) are shown to be able to track the thin POF FBGs and they are finally applied in a prototype...

  3. A Novel Design of Grooved Fibers for Fiber-Optic Localized Plasmon Resonance Biosensors

    OpenAIRE

    Lai-Kwan Chau; Wan-Yun Li; Wei-Te Wu; Tzu-Chien Chao; Chun-Ping Jen; Ching-Te Huang

    2009-01-01

    Bio-molecular recognition is detected by the unique optical properties of self-assembled gold nanoparticles on the unclad portions of an optical fiber whose surfaces have been modified with a receptor. To enhance the performance of the sensing platform, the sensing element is integrated with a microfluidic chip to reduce sample and reagent volume, to shorten response time and analysis time, as well as to increase sensitivity. The main purpose of the present study is to design grooves on the o...

  4. Polydimethylsiloxane fibers for optical fiber sensor of displacement

    Science.gov (United States)

    Martincek, Ivan; Pudis, Dusan; Gaso, Peter

    2013-09-01

    The paper describes the preparation of polydimethylsiloxane (PDMS) fiber integrated on the conventional optical fibers and their use for optical fiber displacement sensor. PDMS fiber was made of silicone elastomer Sylgard 184 (Dow Corning) by drawing from partially cured silicone. Optical fiber displacement sensor using PDMS fiber is based on the measurement of the local minimum of optical signal in visible spectral range generated by intermodal interference of circularly symmetric modes. Position of the local minimum in spectral range varies by stretching the PDMS fiber of 230 ?m in the wavelength range from 688 to 477 nm. In the stretched PDMS fiber is possible to determine the longitudinal displacement with an accuracy of approximately 1 micrometer.

  5. Application of active heat pulse method with fiber optic temperature sensing for estimation of wetting bulbs and water distribution in drip emitters.

    OpenAIRE

    Gil Rodríguez, María; Rodríguez Sinobas, Leonor; Benitez Buelga, Javier; Sánchez Calvo, Raúl

    2013-01-01

    Through the use of the Distributed Fiber Optic Temperature Measurement (DFOT) method, it is possible to measure the temperature in small intervals (on the order of centimeters) for long distances (on the order of kilometers) with a high temporal frequency and great accuracy. The heat pulse method consists of applying a known amount of heat to the soil and monitoring the temperature evolution, which is primarily dependent on the soil moisture content. The use of both methods, which is called t...

  6. Optical fiber coatings for biomedical applications

    Science.gov (United States)

    Biswas, Dipak R.

    1992-07-01

    Silica optical fibers commonly are used for diagnostic, endoscopic, and surgical applications in medical industries. Optical fiber coatings play an important role in fiber strength, reliability, and biocompatibility. Three major coatings are commonly used on optical fibers: (1) polymeric coatings, such as UV-cured acrylate, silicone, and polyimide; (2) metallic coatings such as aluminum, indium, tin, and gold; and (3) inorganic coatings such as oxides, carbides, nitrides, and carbon. In the medical industry, polymeric coatings are used widely. Metallic and inorganic coatings on optical fibers can also be used. I describe the strength, fatigue, and biocompatibility of silica fibers with different coatings.

  7. Fiber optic bundle array wide field-of-view optical receiver for free space optical communications.

    Science.gov (United States)

    Hahn, Daniel V; Brown, David M; Rolander, Nathan W; Sluz, Joseph E; Venkat, Radha

    2010-11-01

    We propose a design for a free space optical communications (FSOC) receiver terminal that offers an improved field of view (FOV) in comparison to conventional FSOC receivers. The design utilizes a microlens to couple the incident optical signal into an individual fiber in a bundle routed to remote optical detectors. Each fiber in the bundle collects power from a solid angle of space; utilizing multiple fibers enhances the total FOV of the receiver over typical single-fiber designs. The microlens-to-fiber-bundle design is scalable and modular and can be replicated in an array to increase aperture size. The microlens is moved laterally with a piezoelectric transducer to optimize power coupling into a given fiber core in the bundle as the source appears to move due to relative motion between the transmitter and receiver. The optimum position of the lens array is determined via a feedback loop whose input is derived from a position sensing detector behind another lens. Light coupled into like fibers in each array cell is optically combined (in fiber) before illuminating discrete detectors. PMID:21042349

  8. Selective Serial Multi-Antibody Biosensing with TOPAS Microstructured Polymer Optical Fibers

    Directory of Open Access Journals (Sweden)

    Lars H. Pedersen

    2013-03-01

    Full Text Available We have developed a fluorescence-based fiber-optical biosensor, which can selectively detect different antibodies in serial at preselected positions inside a single piece of fiber. The fiber is a microstructured polymer optical fiber fabricated from TOPAS cyclic olefin copolymer, which allows for UV activation of localized sensor layers inside the holes of the fiber. Serial fluorescence-based selective sensing of Cy3-labelled ?-streptavidin and Cy5-labelled ?-CRP antibodies is demonstrated.

  9. Selective Serial Multi-Antibody Biosensing with TOPAS Microstructured Polymer Optical Fibers

    DEFF Research Database (Denmark)

    Emiliyanov, Grigoriy Andreev; Høiby, Poul E.; Pedersen, Lars H.; Bang, Ole

    2013-01-01

    We have developed a fluorescence-based fiber-optical biosensor, which can selectively detect different antibodies in serial at preselected positions inside a single piece of fiber. The fiber is a microstructured polymer optical fiber fabricated from TOPAS cyclic olefin copolymer, which allows for UV activation of localized sensor layers inside the holes of the fiber. Serial fluorescence-based selective sensing of Cy3-labelled ?-streptavidin and Cy5-labelled ?-CRP antibodies is demonstrated.

  10. Radiation damage in optical fibers

    International Nuclear Information System (INIS)

    In connection with efforts to construct an optical fiber which is radiation resistant, it is important to understand the mechanisms for radiation-related damage and the effects of the various glass constituents on the basic silica structure. The present investigation is concerned with the results of studies involving an application of transmission, thermoluminescence, and photoluminescence techniques. It is found that for doses up to at least 30,000 rads the induced transmission loss is linear for a wavelength of 0.82 micron. While a high phosphorous content reduces the sensitivity of the fibers to radiation, a low concentration (around 2 mol%) actually increases the sensitivity

  11. Temperature-independent polymer optical fiber evanescent wave sensor.

    Science.gov (United States)

    Zhong, Nianbing; Liao, Qiang; Zhu, Xun; Zhao, Mingfu; Huang, Yun; Chen, Rong

    2015-01-01

    Although the numerous advantages of polymer optical fibers have been exploited in the fields of sensors and telecommunications, such fibers still experience a critical problem: the temperature dependency. Therefore, we explored the temperature-independent operation of a polymer fiber-optic evanescent wave sensor immersed in distilled water. We investigated variations in the surface morphology, deformation trajectory, refractive index, and weight of the fiber-sensing region with varying water temperature. We also examined the spectral transmission and transmitted light intensity of fibers subjected to a heating-cooling treatment. We observed that the light-transmission modes and sensitivity of the sensor were affected by changes in the surface morphology, diameter, and refractive index of the sensing region caused by changes in temperature. The transmitted light intensity of the sensor was maintained at a constant level after five cycles of the heating-cooling treatment, after which the fibers exhibited a smooth surface, low refractive index, and large fiber diameter. Consequently, we utilized the heating-cooling-treated fiber to realize a temperature-independent, U-shaped polymer fiber-optic evanescent wave sensor. The temperature independence was evaluated using glucose solutions in the range of 10 to 70?°C. The fabricated sensor showed significant temperature independence and high degree of consistency in measuring solutions. PMID:26112908

  12. Generalized fiber Fourier optics.

    Science.gov (United States)

    Cincotti, Gabriella

    2011-06-15

    A twofold generalization of the optical schemes that perform the discrete Fourier transform (DFT) is given: new passive planar architectures are presented where the 2 × 2 3 dB couplers are replaced by M × M hybrids, reducing the number of required connections and phase shifters. Furthermore, the planar implementation of the discrete fractional Fourier transform (DFrFT) is also described, with a waveguide grating router (WGR) configuration and a properly modified slab coupler. PMID:21686007

  13. Optical fiber reliability in subsea monitoring

    Science.gov (United States)

    Nagarkar, Kaustubh; Ostroverkhov, Victor; Balasubramaniam, Mahadevan; Rubinsztajn, Slawomir; Koste, Glenn; Dekate, Sachin; Mandal, Sudeep; Stecher, Thomas

    2015-05-01

    Fiber optic cables have been successfully deployed in ocean floors for decades to enable trans-oceanic telecommunication. The impact of strain and moisture on optical fibers has been thoroughly studied in the past 30 years. Cable designs have been developed to minimize strain on the fibers and prevent water uptake. As a result, the failure rates of optical fibers in subsea telecommunication cables due to moisture and strain are negligible. However, the relatively recent use of fiber optic cables to monitor temperature, acoustics, and especially strain on subsea equipment adds new reliability challenges that need to be mitigated. This paper provides a brief overview of the design for reliability considerations of fiber optic cables for subsea asset condition monitoring (SACM). In particular, experimental results on fibers immersed in water under varying accelerated conditions of static stress and temperature are discussed. Based on the data, an assessment of the survivability of optical fibers in the subsea monitoring environment is presented.

  14. All-optical devices in polymer optical fiber

    Science.gov (United States)

    Kuzyk, Mark G.; Garvey, Dennis W.; Vigil, Steven R.; Welker, David J.

    1999-07-01

    We report on polymer optical fiber devices for sensors, optical switches/logic, and optical actuators. In this paper, we give a brief overview of polymer fibers, discuss recent all-optical switching results, and describe how an optical sensor and actuator can be built into a single fiber device. Future technologies that are made possible with such optical devices and photomechanical mechanisms are also discussed.

  15. Design and optimization of microstructured optical fiber sensors

    Science.gov (United States)

    Jewart, Charles Milford

    2011-12-01

    The integration of sensor networks into large civil and mechanical structures is becoming an important engineering practice to ensure the structural health of important infrastructure and power generation facilities. The temperature, pressure, and internal stress distribution within the structures are key parameters to monitor the structural health of a system. Optical fiber sensors are one of the most common sensing elements used in the structural health monitoring due to their compact size, low cost, electrical immunity, and multiplexing ability. In this dissertation, the design and optimization of air-hole microstructured optical fibers for use as application specific sensors is presented. Air hole matrices are used to design fiber cores with a large birefringence; while air hole arrays within the fiber cladding are studied and optimized to engineer unique geometries that can give desired sensitivity and directionality of the fiber sensors. A pure silica core microstructured photonic crystal fiber was designed for hydrostatic pressure sensing. The impact of the surrounding air-holes to the propagation mode profiles and indices were studied and improved. To improve directionality and sensitivity of fiber sensors, air holes in the fiber cladding were implemented and optimized in the design of the fiber. Finite element analysis simulations were performed to elicit the correlation between air-hole configuration and the fiber sensor's performance and impact of the fiber's opto-mechanic properties. To measure pressure and stress at high temperature, an ultrafast laser was used to inscribe type II gratings in two-hole microstructured optical fibers and suspended core fibers. The fiber Bragg grating resonance wavelength shift and peak splitting were studied as a function of external pressure, bending, and lateral compression. Fiber sensors in two-hole fibers show stable and reproducible operation above 800°C. Fiber grating sensor in suspended core fibers exhibits high directionality to transverse stress, and insensitivity to bending. All experimental results are in good agreement with the simulations. This works demonstrates that ingenious design and engineering of air hole matrices in optical fiber's cladding and core can lead to multi-functional and multiplexable fiber sensors that were previously unattainable using traditional solid-core solid cladding fiber.

  16. Fabrication Quality Analysis of a Fiber Optic Refractive Index Sensor Created by CO2 Laser Machining

    OpenAIRE

    Wei-Te Wu; Bo-Kuan Yeh; Jaw-Luen Tang; Chien-Hsing Chen

    2013-01-01

    This study investigates the CO2 laser-stripped partial cladding of silica-based optic fibers with a core diameter of 400 ?m, which enables them to sense the refractive index of the surrounding environment. However, inappropriate treatments during the machining process can generate a number of defects in the optic fiber sensors. Therefore, the quality of optic fiber sensors fabricated using CO2 laser machining must be analyzed. The results show that analysis of the fiber core size after machin...

  17. An Integrated Photoluminescence Sensing Platform Using a Single-Multi-Mode Fiber Coupler-Based Probe

    OpenAIRE

    Feng Long; Anna Zhu; Hanchang Shi

    2014-01-01

    We demonstrate an integrated fiber optic photoluminescence sensing platform using a novel single-multi-mode fiber coupler (SMFC)-based probe with high collection efficiency for fluorescence signals. The SMFC, prepared using fused biconical taper technology, not only transmits excitation light, but also collects and transmits fluorescence. The entire system does not use complex optical components and rarely requires optical alignment. The simple structure of the SMFC considerably improves the ...

  18. Interferometric fiber-optic bending / nano-displacement sensor using plastic dual-core fiber

    CERN Document Server

    Qu, H; Skorobogatiy, M

    2014-01-01

    We demonstrate an interferometric fiber-optic bending/micro-displacement sensor based on a plastic dual-core fiber with one end coated with a silver mirror. The two fiber cores are first excited with the same laser beam, the light in each core is then back-reflected at the mirror-coated fiber-end, and, finally, the light from the two cores is made to interfere at the coupling end. Bending of the fiber leads to shifting interference fringes that can be interrogated with a slit and a single photodetector. We find experimentally that the resolution of our bending sensor is ~3x10-4 m-1 for sensing of bending curvature, as well as ~70 nm for sensing of displacement of the fiber tip. We demonstrate operation of our sensor using two examples. One is weighting of the individual micro-crystals of salt, while the other one is monitoring dynamics of isopropanol evaporation.

  19. Optical Fiber Grating based Sensors

    DEFF Research Database (Denmark)

    Michelsen, Susanne

    2003-01-01

    In this thesis differenct optical fiber gratings are used for sensor purposes. If a fiber with a core concentricity error (CCE) is used, a directional dependent bend sensor can be produced. The CCE direction can be determined by means of diffraction. This makes it possible to produce long......-period gratings in a fiber with a CCE direction parallel or perpendicular to the writing direction. The maximal bending sensitivity is independent on the writing direction, but the detailed bending response is different in the two cases. A temperature and strain sensor, based on a long-period grating and two...... sampled gratings, was produced and investigated. It is based on the different temperature and strain response of these gratings. Both a transfer matrix method and an overlap calculation is performed to explain the sensor response. Another type of sensor is based on tuning and modulation of a laser...

  20. Quasi-distributed long-gauge fiber optic sensor system.

    Science.gov (United States)

    Linec, Matjaz; Donlagi?, Denis

    2009-07-01

    This paper presents a quasi-distributed, long-gauge, sensor system for measurement optical path length variation. This system can be directly applied to long gauge strain and/or temperature sensing. The proposed sensor system is comprised of sensing fiber, which is divided into the sensor's segments separated by semi reflective mirrors made out of standard optical connectors. Short duration radio-frequency modulated optical bursts are launched into the sensing fiber and phase differences among individual reflected bursts are measured to determine the optical path-length variations among neighboring mirrors. Twenty sensing fiber segments were successfully addressed by a single-signal processor, while relying on standard telecommunication PIN diode, and a Fabry Perot laser diode. The resolution of a fiber-length variation better than 5 microm was demonstrated in practice. Since the long sections of fiber can be employed for constructing individual sensors within the sensor's array, a microstrain resolution can be achieved in practice. The drift of the sensor's system can be predominantly attributed to the temperature sensitivity of the electronic components, which proved to be below 20 microm/ degrees C. The entire system relies on simple and widely-used components that are low-cost. PMID:19582067

  1. Active Optical Fibers Doped with Ceramic Nanocrystals

    Directory of Open Access Journals (Sweden)

    Jan Mrazek

    2014-01-01

    Full Text Available Erbium-doped active optical fiber was successfully prepared by incorporation of ceramic nanocrystals inside a core of optical fiber. Modified chemical vapor deposition was combined with solution-doping approach to preparing preform. Instead of inorganic salts erbium-doped yttrium-aluminium garnet nanocrystals were used in the solution-doping process. Prepared preform was drawn into single-mode optical fiber with a numerical aperture 0.167. Optical and luminescence properties of the fiber were analyzed. Lasing ability of prepared fiber was proofed in a fiber-ring set-up. Optimal laser properties were achieved for a fiber length of 20~m. The slope efficiency of the fiber-laser was about 15%. Presented method can be simply extended to the deposition of other ceramic nanomaterials.

  2. Distribution automation applications of fiber optics

    Science.gov (United States)

    Kirkham, Harold; Johnston, A.; Friend, H.

    1989-01-01

    Motivations for interest and research in distribution automation are discussed. The communication requirements of distribution automation are examined and shown to exceed the capabilities of power line carrier, radio, and telephone systems. A fiber optic based communication system is described that is co-located with the distribution system and that could satisfy the data rate and reliability requirements. A cost comparison shows that it could be constructed at a cost that is similar to that of a power line carrier system. The requirements for fiber optic sensors for distribution automation are discussed. The design of a data link suitable for optically-powered electronic sensing is presented. Empirical results are given. A modeling technique that was used to understand the reflections of guided light from a variety of surfaces is described. An optical position-indicator design is discussed. Systems aspects of distribution automation are discussed, in particular, the lack of interface, communications, and data standards. The economics of distribution automation are examined.

  3. Fiber-optic communication systems

    CERN Document Server

    Agrawal, Govind P

    2010-01-01

    This book provides a comprehensive account of fiber-optic communication systems. The 3rd edition of this book is used worldwide as a textbook in many universities. This 4th edition incorporates recent advances that have occurred, in particular two new chapters. One deals with the advanced modulation formats (such as DPSK, QPSK, and QAM) that are increasingly being used for improving spectral efficiency of WDM lightwave systems. The second chapter focuses on new techniques such as all-optical regeneration that are under development and likely to be used in future communication systems. All othe

  4. Development of pulsed fiber lasers for long-range remote sensing

    Science.gov (United States)

    Di Teodoro, Fabio; Belden, Paul; Ionov, Pavel; Werner, Nicolette; Fathi, Gilda

    2014-03-01

    Pulsed fiber lasers bear great promise as optical transmitters for remote sensors, having tight size, power consumption, and ruggedness constraints. We discuss recently introduced laser architectures and components supporting power scaling of efficient fiber-based laser sources for long-range operation consistent with imaging and/or spectroscopic sensing from high-altitude and space-based platforms.

  5. Optical carrier-based microwave interferometers for sensing application

    Science.gov (United States)

    Huang, Jie; Lan, Xinwei; Wang, Hanzheng; Yuan, Lei; Xiao, Hai

    2014-06-01

    Optical fiber interferometers (OFIs) have been extensively utilized for precise measurements of various physical/chemical quantities (e.g., temperature, strain, pressure, rotation, refractive index, etc.). However, the random change of polarization states along the optical fibers and the strong dependence on the materials and geometries of the optical waveguides are problematic for acquiring high quality interference signal. Meanwhile, difficulty in multiplexing has always been a bottleneck on the application scopes of OFIs. Here, we present a sensing concept of optical carrier based microwave interferometry (OCMI) by reading optical interferometric sensors in microwave domain. It combines the advantages from both optics and microwave. The low oscillation frequency of the microwave can hardly distinguish the optical differences from both modal and polarization dispersion making it insensitive to the optical waveguides/materials. The phase information of the microwave can be unambiguitly resolved so that it has potential in fully distributed sensing. The OCMI concept has been implemented in different types of interferometers (i.e., Michelson, Mach-Zehnder, Fabry-Perot) among different optical waveguides (i.e., singlemode, multimode, and sapphire fibers) with excellent signal-to-noise ratio (SNR) and low polarization dependence. A spatially continuous distributed strain sensing has been demonstrated.

  6. Flight demonstration of fiber optic sensors

    Science.gov (United States)

    Elster, Jennifer L.; Trego, Angela; Catterall, Charles; Averett, Josh; Jones, Mark E.; Evans, Mishell K.; Fielder, Bob

    2003-07-01

    Luna Innovations has developed a prototype 8-channel fiber optic sensor system to demonstrate fiber optic sensor operation in flight environments. As an intial flight demonstration, long period grating (LPG) relative humidity sensors along with extrinsic Fabry-Perot interferometric (EFPI) pressure and temperature sensors were installed in an aging Delta 767-300ER jet. The fiber optic signal-conditioning system is a multi-purpose platform that can also be used to operate other types of fiber optic LPG and EFPI sensors, including strain gages, metal-ion corrosion sensors, and fiber Bragg grating (FBG) sensors. The system configuration and operation is described.

  7. Engineering modes in optical fibers with metamaterial

    DEFF Research Database (Denmark)

    Yan, Min; Mortensen, Asger; Qiu, Min

    2009-01-01

    In this paper, we report a preliminary theoretical study on optical fibers with fine material inclusions whose geometrical inhomogeneity is almost indistinguishable by the operating wavelength.We refer to such fibers as metamaterial optical fibers, which can conceptually be considered as an exten...

  8. Use of optical fibers in spectrophotometry

    Science.gov (United States)

    Ramsey, Lawrence W.

    1988-01-01

    The use of single or small numbers of fiber optic fibers in astronomical spectroscopy with the goal of greater spectrophotometric and radial velocity accuracy is discussed. The properties of multimode step index fibers which are most important for this application are outlined, as are laboratory tests of currently available fibers.

  9. Research progress in the key device and technology for fiber optic sensor network

    Science.gov (United States)

    Liu, Deming; Sun, Qizhen; Lu, Ping; Xia, Li; Sima, Chaotan

    2016-03-01

    The recent research progress in the key device and technology of the fiber optic sensor network (FOSN) is introduced in this paper. An architecture of the sensor optical passive network (SPON), by employing hybrid wavelength division multiplexing/time division multiplexing (WDM/TDM) techniques similar to the fiber communication passive optical network (PON), is proposed. The network topology scheme of a hybrid TDM/WDM/FDM (frequency division multiplexing) three-dimension fiber optic sensing system for achieving ultra-large capacity, long distance, and high resolution sensing performance is performed and analyzed. As the most important device of the FOSN, several kinds of light source are developed, including the wideband multi-wavelength fiber laser operating at C band, switchable and tunable 2 μm multi-wavelength fiber lasers, ultra-fast mode-locked fiber laser, as well as the optical wideband chaos source, which have very good application prospects in the FOSN. Meanwhile, intelligent management techniques for the FOSN including wideband spectrum demodulation of the sensing signals and real-time fault monitoring of fiber links are presented. Moreover, several typical applications of the FOSN are also discussed, such as the fiber optic gas sensing network, fiber optic acoustic sensing network, and strain/dynamic strain sensing network.

  10. Fiber-optically sensorized composite wing

    Science.gov (United States)

    Costa, Joannes M.; Black, Richard J.; Moslehi, Behzad; Oblea, Levy; Patel, Rona; Sotoudeh, Vahid; Abouzeida, Essam; Quinones, Vladimir; Gowayed, Yasser; Soobramaney, Paul; Flowers, George

    2014-04-01

    Electromagnetic interference (EMI) immune and light-weight, fiber-optic sensor based Structural Health Monitoring (SHM) will find increasing application in aerospace structures ranging from aircraft wings to jet engine vanes. Intelligent Fiber Optic Systems Corporation (IFOS) has been developing multi-functional fiber Bragg grating (FBG) sensor systems including parallel processing FBG interrogators combined with advanced signal processing for SHM, structural state sensing and load monitoring applications. This paper reports work with Auburn University on embedding and testing FBG sensor arrays in a quarter scale model of a T38 composite wing. The wing was designed and manufactured using fabric reinforced polymer matrix composites. FBG sensors were embedded under the top layer of the composite. Their positions were chosen based on strain maps determined by finite element analysis. Static and dynamic testing confirmed expected response from the FBGs. The demonstrated technology has the potential to be further developed into an autonomous onboard system to perform load monitoring, SHM and Non-Destructive Evaluation (NDE) of composite aerospace structures (wings and rotorcraft blades). This platform technology could also be applied to flight testing of morphing and aero-elastic control surfaces.

  11. Fiber Optic Pressure Sensor using Multimode Interference

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Perez, V I; Sanchez-Mondragon, J J [INAOE, Apartado Postal 51 y 216, Puebla 72000 (Mexico); Basurto-Pensado, M A [CIICAp, Universidad Autonoma del Estado de Morelos (Mexico); LiKamWa, P [CREOL, University of Central Florida, Orlando, FL 32816 (United States); May-Arrioja, D A, E-mail: iruiz@inaoep.mx, E-mail: mbasurto@uaem.mx, E-mail: delta_dirac@hotmail.com, E-mail: daniel_may_arrioja@hotmail.com [UAT Reynosa Rodhe, Universidad Autonoma de Tamaulipas (Mexico)

    2011-01-01

    Based on the theory of multimode interference (MMI) and self-image formation, we developed a novel intrinsic optical fiber pressure sensor. The sensing element consists of a section of multimode fiber (MMF) without cladding spliced between two single mode fibers (SMF). The MMI pressure sensor is based on the intensity changes that occur in the transmitted light when the effective refractive index of the MMF is changed. Basically, a thick layer of Polydimethylsiloxane (PDMS) is placed in direct contact with the MMF section, such that the contact area between the PDMS and the fiber will change proportionally with the applied pressure, which results in a variation of the transmitted light intensity. Using this configuration, a good correlation between the measured intensity variations and the applied pressure is obtained. The sensitivity of the sensor is 3 {mu}V/psi, for a range of 0-60 psi, and the maximum resolution of our system is 0.25 psi. Good repeatability is also observed with a standard deviation of 0.0019. The key feature of the proposed pressure sensor is its low fabrication cost, since the cost of the MMF is minimal.

  12. Fiber Optic Pressure Sensor using Multimode Interference

    International Nuclear Information System (INIS)

    Based on the theory of multimode interference (MMI) and self-image formation, we developed a novel intrinsic optical fiber pressure sensor. The sensing element consists of a section of multimode fiber (MMF) without cladding spliced between two single mode fibers (SMF). The MMI pressure sensor is based on the intensity changes that occur in the transmitted light when the effective refractive index of the MMF is changed. Basically, a thick layer of Polydimethylsiloxane (PDMS) is placed in direct contact with the MMF section, such that the contact area between the PDMS and the fiber will change proportionally with the applied pressure, which results in a variation of the transmitted light intensity. Using this configuration, a good correlation between the measured intensity variations and the applied pressure is obtained. The sensitivity of the sensor is 3 ?V/psi, for a range of 0-60 psi, and the maximum resolution of our system is 0.25 psi. Good repeatability is also observed with a standard deviation of 0.0019. The key feature of the proposed pressure sensor is its low fabrication cost, since the cost of the MMF is minimal.

  13. Real-time In-Flight Strain and Deflection Monitoring with Fiber Optic Sensors

    Science.gov (United States)

    Richards, Lance; Parker, Allen R.; Ko, William L.; Piazza, Anthony

    2008-01-01

    This viewgraph presentation reviews Dryden's efforts to develop in-flight monitoring based on Fiber Optics. One of the motivating factors for this development was the breakup of the Helios aircraft. On Ikhana the use of fiber optics for wing shape sensing is being developed. They are being used to flight validate fiber optic sensor measurements and real-time wing shape sensing predictions on NASA's Ikhana vehicle; validate fiber optic mathematical models and design tools; Assess technical viability and, if applicable, develop methodology and approach to incorporate wing shape measurements within the vehicle flight control system, and develop and flight validate advanced approaches to perform active wing shape control.

  14. Electron spin manipulation and readout through an optical fiber

    OpenAIRE

    I. V. Fedotov; L. V. Doronina-Amitonova; Voronin, A. A.; Levchenko, A. O.; S. A. Zibrov; Sidorov-Biryukov, D. A.; Fedotov, A. B.; Velichansky, V. L.; A. M. Zheltikov

    2014-01-01

    The electron spin of nitrogen--vacancy (NV) centers in diamond offers a solid-state quantum bit and enables high-precision magnetic-field sensing on the nanoscale. Implementation of these approaches in a fiber format would offer unique opportunities for a broad range of technologies ranging from quantum information to neuroscience and bioimaging. Here, we demonstrate an ultracompact fiber-optic probe where a diamond microcrystal with a well-defined orientation of spin quantization NV axes is ...

  15. Chronology of Fabry-Perot Interferometer Fiber-Optic Sensors and Their Applications: A Review

    OpenAIRE

    Md. Rajibul Islam; Muhammad Mahmood Ali; Man-Hong Lai; Kok-Sing Lim; Harith Ahmad

    2014-01-01

    Optical fibers have been involved in the area of sensing applications for more than four decades. Moreover, interferometric optical fiber sensors have attracted broad interest for their prospective applications in sensing temperature, refractive index, strain measurement, pressure, acoustic wave, vibration, magnetic field, and voltage. During this time, numerous types of interferometers have been developed such as Fabry-Perot, Michelson, Mach-Zehnder, Sagnac Fiber, and Common-path interferome...

  16. Fiber Optics For Aircraft Engine/Inlet Control

    Science.gov (United States)

    Baumbick, Robert J.

    1982-01-01

    A review of NASA programs which focus on the use of fiber optics for aircraft engine/inlet control is presented. Fiber optics for aircraft control is attractive because of its inherent immunity to EMI and RFI noise. Optical signals can be safely transmitted through areas that contain flammable or explosive materials. The use of optics also makes remote sensing feasible, eliminating the need for electrical wires to be connected between sensors and computers. Using low level optical signals to control actuators is also feasible when power is generated at the actuator. For engine/inlet control applications, fiber optic cables and cornectors will be subjected to nacelle air temperatures. These temperatures range between -55°C to 260°C. Each application of fiber optics for aircraft control has different requirements for both the optical cables and optical connectors. Sensors that measure position and speed using slotted plates can use lossy cables and bundle type connectors if data transfer is in the parallel mode. If position and speed signals are multiplexed cable and connector requirements change. Other sensors that depend on changes in transmission through materials require dependable characteristics of both the optical cable and optical connectors. A variety of sensor types are reviewed, including rotary position encoders, tachometers, temperature sensors, and blade tip clearance sensors for compressors and turbines. Research on a gallium arsenide photoswitch for optically-switched actuators that operate at 250°C is also described.

  17. The Effects of High Temperature and Nuclear Radiation on the Optical Transmission of Silica Optical Fibers

    Science.gov (United States)

    Hawn, David P.

    Distributed measurements made with fiber optic instrumentation have the potential to revolutionize data collection for facility monitoring and process control in industrial environments. Dozens of sensors etched into a single optical fiber can be used to instrument equipment and structures so that dozens of spatially distributed temperature measurements, for example, can be made quickly using one optical fiber. Optically based sensors are commercially available to measure temperature, strain, and other physical quantities that can be related to strain, such as pressure and acceleration. Other commercially available technology eliminates the need to etch discrete sensors into an optical fiber and allows temperature measurements to be made along the length of an ordinary silica fiber. Distributed sensing with optical instrumentation is commonly used in the petroleum industry to measure the temperature and pressure profiles in down hole applications. The U.S. Department of Energy is interested in extending the distributed sensing capabilities of optical instrumentation to high temperature reactor radiation environments. For this technology extension to be possible, the survivability of silica optical fibers needed to be determined in this environment. In this work the optical attenuation added to silica optical fiber exposed simultaneously to reactor radiation and temperatures to 1000°C was experimentally determined. Optical transmission measurements were made in-situ from 400nm-2300nm. For easy visualization, all of the results generated in this work were processed into movies that are available publicly [1]. In this investigation, silica optical fibers were shown to survive optically and mechanically in a reactor radiation environment to 1000°C. For the combined high temperature reactor irradiation experiments completed in this investigation, the maximum attenuation increase in the low-OH optical fibers was around 0.5db/m at 1550nm and 0.6dB/m at 1300nm. The radiation induced optical attenuation primarily affected wavelengths less than 1000nm and this attenuation cannot be avoided in silica. Thermal effects dominated the increase in attenuation at wavelengths above 1000nm and it may be possible to mitigate these effects. Fortuitously, commercial optical instrumentation typically utilizes wavelengths centered around 1300nm and 1550nm where the radiation induced attenuation was minimal. The maximum continuous use temperature of silica optical fiber may be limited to 900°C with intermittent use to 1000°C. The silica optical fibers tested in this project are inexpensive and commercially available. Optical sensors were not tested in this project and development and testing of radiation hard optical sensors is recommended as future work.

  18. Comparison of optical fiber Bragg grating hydrogen sensors with Pd-based thin films and sol–gel WO3 coatings

    International Nuclear Information System (INIS)

    Pd-based thin films and sol–gel WO3 coatings are two kinds of hydrogen sensitive elements used in hydrogen concentration sensing and detection. Optical fiber hydrogen sensors are very promising solutions for flammable hydrogen detection, when the sensitive materials are integrated with optical fiber sensors. This paper reviews the sensing performance of optical fiber hydrogen sensors with these two sensitive materials, which are developed at the National Engineering Laboratory for Optical Fiber Sensing Technologies in Wuhan University of Technology. (paper)

  19. Fiber-Optic Ammonia Sensors

    Science.gov (United States)

    Carter, Michael T.

    2003-01-01

    Reversible, colorimetric fiber-optic sensors are undergoing development for use in measuring concentrations of ammonia in air at levels relevant to human health [0 to 50 parts per million (ppm)]. A sensor of this type includes an optical fiber that has been modified by replacing a portion of its cladding with a polymer coat that contains a dye that reacts reversibly with ammonia and changes color when it does so. The change in color is measured as a change in the amount of light transmitted from one end of the fiber to the other. Responses are reversible and proportional to the concentration of ammonia over the range from 9 to 175 ppm and in some cases the range of reversibility extends up to 270 ppm. The characteristic time for the response of a sensor to rise from 10 to 90 percent of full scale is about 25 seconds. These sensors are fully operational in pure carbon dioxide and are not adversely affected by humidity. This work was done by Michael T. Carter

  20. Fiber Optics Physics and Technology

    CERN Document Server

    Mitschke, Fedor

    2010-01-01

    Telephone, telefax, email and internet -- the key ingredient of the inner workings is the conduit: the line which is designed to carry massive amounts of data at breakneck speed. In their data-carrying capacity optical fiber lines beat other technologies (copper cable, microwave beacons, satellite links) hands down, at least in the long haul. This book tells you all you want to know about optical fibers: Their structure, their light-guiding mechanism, their material and manufacture, their use. Several effects tend to degrade the signal as it travels down the fiber: they are spelled out in detail. Nonlinear processes are given due consideration for a twofold reason: On the one hand they are fundamentally different from the more familiar processes in electrical cable. On the other hand, they form the basis of particularly interesting and innovative applications, provided they are understood well enough. A case in point is the use of so-called solitons, i.e. special pulses of light which have the wonderful prope...

  1. Optical Fiber Grating based Sensors

    DEFF Research Database (Denmark)

    Michelsen, Susanne

    2003-01-01

    In this thesis differenct optical fiber gratings are used for sensor purposes. If a fiber with a core concentricity error (CCE) is used, a directional dependent bend sensor can be produced. The CCE direction can be determined by means of diffraction. This makes it possible to produce long-period gratings in a fiber with a CCE direction parallel or perpendicular to the writing direction. The maximal bending sensitivity is independent on the writing direction, but the detailed bending response is different in the two cases. A temperature and strain sensor, based on a long-period grating and two sampled gratings, was produced and investigated. It is based on the different temperature and strain response of these gratings. Both a transfer matrix method and an overlap calculation is performed to explain the sensor response. Another type of sensor is based on tuning and modulation of a laser wavelength. It is shown that it is possible to tune and modulate a DFB fiber laser with both strain from a piezoelectric transducer and by temperature through resistive heating of a methal film. Both a chemical deposited silver layer and an electron-beam evaporation technique has been investigated, to find the most reproducible method. Such a laser can be applied for gas monitoring and it can be stabilized by locking it to an absorption line. The locked laser has a stability of ~2 MHz, which makes it suitable as a wavelength standard in the 1.5 um telecommunication band.

  2. Hardened fiber optic links for nuclear industry

    International Nuclear Information System (INIS)

    Typical behaviour of fiber optic exposed to a steady state gamma ray irradiation show the improvement of induced loss value by appropriate photo bleaching in pure silica core fibers. Taking care of the environment in industrial nuclear process, two fiber optic transmission links have been designed. To improve performances of servomanipulators used in nuclear fuel reprocessing plants an experimental three fiber data link was made with tested hardened components and its functionality is anticipated up to 105 Gy

  3. A Highly Sensitive Fiber Optic Sensor Based on Two-Core Fiber for Refractive Index Measurement

    OpenAIRE

    Daniel Alberto May-Arrioja; Miguel Torres-Cisneros; José Javier Sánchez-Mondragón; José Rafael Guzmán-Sepúlveda; Rafael Guzmán-Cabrera

    2013-01-01

    A simple and compact fiber optic sensor based on a two-core fiber is demonstrated for high-performance measurements of refractive indices (RI) of liquids. In order to demonstrate the suitability of the proposed sensor to perform high-sensitivity sensing in a variety of applications, the sensor has been used to measure the RI of binary liquid mixtures. Such measurements can accurately determine the salinity of salt water solutions, and detect the water content of adulterated alcoholic beverage...

  4. Fiber optic probes for laser light scattering: Ground based evaluation for micgrogravity flight experimentation. Integrated coherent imaging fiber optic systems for laser light scattering and other applications

    Science.gov (United States)

    Dhadwal, Harbans Singh

    1994-01-01

    The research work presented in this report has established a new class of backscatter fiber optics probes for remote dynamic light scattering capability over a range of scattering angles from 94 degrees to 175 degrees. The fiber optic probes provide remote access to scattering systems, and can be utilized in either a noninvasive or invasive configuration. The fiber optics create an interference free data channel to inaccessible and harsh environments. Results from several studies of concentrated suspension, microemulsions, and protein systems are presented. The second part of the report describes the development of a new technology of wavefront processing within the optical fiber, that is, integrated fiber optics. Results have been very encouraging and the technology promises to have significant impact on the development of fiber optic sensors in a variety of fields ranging from environmental monitoring to optical recording, from biomedical sensing to photolithography.

  5. Analog fiber optic transmission link

    International Nuclear Information System (INIS)

    An analog fiber optic transmission link (FOTL) has been designed for relaying signals from equipment held at high voltage potentials to equipment at ground potential. The need for a fiber link arises from the requirements of low energy, light ion experiments conducted at the Triangle Universities Nuclear Laboratory. In these experiments, ions are accelerated and transported to a high voltage scattering chamber and the FOTL is used to transmit signals from the scattering chamber to remote data acquisition systems. The performance of the link is mainly driven by the stringent requirements needed for successful transmission of analog pulses from radiation detectors located in the scattering chamber. The FOTL consists of a transmitter, receiver, and baseline restorer that are capable of transmitting radiation detector pulses without pulse height distortion, thus allowing high resolution energy measurements. The FOTL is also suitable for use with a wide variety of other analog signal types

  6. Axial strain and temperature sensing characteristics of the single-coreless-single mode fiber structure-based fiber ring laser

    Science.gov (United States)

    Liu, Zhi-bo; Yin, Bin; Liang, Xiao; Bai, Yunlong; Tan, Zhongwei; Liu, Shuo; Li, Yang; Liu, Yan; Jian, Shuisheng

    2014-06-01

    This paper experimentally demonstrated a singlemode-coreless-singlemode (SCS) fiber structure-based fiber ring cavity laser for strain and temperature measurement. The basis of the sensing system is the multimodal interference occurs in coreless fiber, and the transmission spectrum is sensitive to the ambient perturbation. In this sensing system, the SCS fiber structure not only acts as the sensing head of the sensor but also the band-pass filter of the ring laser. Blue shift with strain sensitivity of ˜ -2 pm/?? ranging from 0 to 730 ?? and red shift with temperature sensitivity of ˜ 11 pm/°C ranging from 5 to 75 °C have been achieved. Experimental results also show the proposal has great potential in using long-distance operation. The fiber ring laser sensing system has a optical signal to noise ratio (OSNR) more than 50 and 3 dB bandwidth less than 0.05 nm. The result shows that the coreless fiber has no improvement of the temperature and axial strain sensitivity. However, compared to the common singlemode-multimode-singlemode fiber structure sensors, the laser sensing system has the additional advantages of high OSNR, high intensity and narrow 3 dB bandwidth, and thus improves the accuracy.

  7. The soliton transmissions in optical fibers

    OpenAIRE

    Leos Bohac

    2010-01-01

    The objective of this paper is to familiarize readers with the basic analytical propagation model of short optical pulses in optical fiber. Based on this model simulation of propagation of the special type of pulse, called a soliton, will be carried out. A soliton transmission is especially attractive in the fiber optic telecommunication systems as it does not change a pulses shape during propagating right-down the fiber link to the receiver. The model of very short pulse propagation is based...

  8. Nanoparticle-doped radioluminescent silica optical fibers.

    Czech Academy of Sciences Publication Activity Database

    Mrázek, Jan; Nikl, Martin; Kašík, Ivan; Podrazký, Ond?ej; Aubrecht, Ivo; Beitlerová, Alena

    Vol. 9228. Bellingham : SPIE, 2014 - (Dorosz, J.; Romaniuk, R.), s. 922805 ISBN 978-1-62841-275-8. ISSN 0277-786X. [15th Symposia on Optical Fibers and their Applications. Bialystok (PL), 29.01.2014-01.02.2014] Institutional support: RVO:67985882 ; RVO:68378271 Keywords : Fiber optic sensors * Nanoparticle s * Optical fibers Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering; CF - Physical ; Theoretical Chemistry (FZU-D)

  9. High Temperature Endurable Fiber Optic Accelerometer

    OpenAIRE

    Yeon-Gwan Lee; Jin-Hyuk Kim; Chun-Gon Kim

    2014-01-01

    This paper presents a low frequency fiber optic accelerometer for application in high temperature environments of civil engineering structures. The reflection-based extrinsic fiber optic accelerometer developed in this study consists of a transmissive grating panel, reflective mirror, and two optical fiber collimators as the transceiver whose function can be maintained up to 130°C. The dynamic characteristics of the sensor probe were investigated and the correlation between the natural freque...

  10. Thermal Strain Analysis of Optic Fiber Sensors

    OpenAIRE

    Chih-Ying Huang; Shiuh-Chuan Her

    2013-01-01

    An optical fiber sensor surface bonded onto a host structure and subjected to a temperature change is analytically studied in this work. The analysis is developed in order to assess the thermal behavior of an optical fiber sensor designed for measuring the strain in the host structure. For a surface bonded optical fiber sensor, the measuring sensitivity is strongly dependent on the bonding characteristics which include the protective coating, adhesive layer and the bonding length. Thermal str...

  11. The development of advanced optical fibers for long-​wave infrared transmission

    OpenAIRE

    Pierre Lucas; Catherine Boussard-Pledel; Allison Wilhelm; Sylvain Danto; Xiang-Hua Zhang; Patrick Houizot; Sebastien Maurugeon; Clément Conseil; Bruno Bureau

    2013-01-01

    Long-wave infrared fibers are used in an increasing number of applications ranging from thermal imaging to bio-sensing. However, the design of optical fiber with low-loss in the far-infrared requires a combination of properties including good rheological characteristics for fiber drawing and low phonon energy for wide optical transparency, which are often mutually exclusive and can only be achieved through fine materials engineering. This paper presents strategies for obtaining low loss fiber...

  12. Optical fiber lasers and amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Snitzer, E.; Po, H.; Tumminelli, R.P.; Hakimi, F.

    1989-03-21

    An optical fiber is described, which comprises: a substantially single-mode core having an index of refraction n/sub 1/ comprised of laser material disposed within a multi-mode cladding having an index of refraction n/sub 2/; and a further cladding having an index of refraction n/sub 3/ surrounding the multi-mode cladding with substantially no space between the further cladding and the multi-mode cladding; wherein the single-mode core is disposed at an offset from the geometric center of the multi-mode cladding.

  13. Enhancing Optical Communications with Brand New Fibers

    DEFF Research Database (Denmark)

    Morioka, Toshio; Awaji, Yoshinari

    2012-01-01

    Optical fibers have often been considered to offer effectively infinite capacity to support the rapid traffic growth essential to our information society. However, as demand has grown and technology has developed, we have begun to realize that there is a fundamental limit to fiber capacity of ~ 100 Tb/s per fiber for systems based on conventional single-core single-mode optical fiber as the transmission medium. This limit arises from the interplay of a number of factors including the Shannon limit, optical fiber nonlinearities, the fiber fuse effect, as well as optical amplifier bandwidth. This article reviews the most recent research efforts around the globe launched over the past few years with a view to overcome these limitations and substantially increase capacity by exploring the last degree of freedom available: the spatial domain. Central to this effort has been the development of brand new fibers for space-division multiplexing and mode-division multiplexing.

  14. Fiber-optical accelerometers based on polymer optical fiber Bragg gratings

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Stefani, Alessio; Bang, Ole; Andresen, Søren; Nielsen, Finn Kryger; Jacobsen, Torben; Rose, Bjarke; Herholdt-Rasmussen, Nicolai

    2010-01-01

    Fiber-optical accelerometers based on polymer optical fiber Bragg gratings (FBGs) are reported. We have written 3mm FBGs for 1550nm operation, characterized their temperature and strain response, and tested their performance in a prototype accelerometer.......Fiber-optical accelerometers based on polymer optical fiber Bragg gratings (FBGs) are reported. We have written 3mm FBGs for 1550nm operation, characterized their temperature and strain response, and tested their performance in a prototype accelerometer....

  15. Optical display for radar sensing

    Science.gov (United States)

    Szu, Harold; Hsu, Charles; Willey, Jefferson; Landa, Joseph; Hsieh, Minder; Larsen, Louis V.; Krzywicki, Alan T.; Tran, Binh Q.; Hoekstra, Philip; Dillard, John T.; Krapels, Keith A.; Wardlaw, Michael; Chu, Kai-Dee

    2015-05-01

    Boltzmann headstone S = kB Log W turns out to be the Rosette stone for Greek physics translation optical display of the microwave sensing hieroglyphics. The LHS is the molecular entropy S measuring the degree of uniformity scattering off the sensing cross sections. The RHS is the inverse relationship (equation) predicting the Planck radiation spectral distribution parameterized by the Kelvin temperature T. Use is made of the conservation energy law of the heat capacity of Reservoir (RV) change T ? S = -?E equals to the internal energy change of black box (bb) subsystem. Moreover, an irreversible thermodynamics ? S > 0 for collision mixing toward totally larger uniformity of heat death, asserted by Boltzmann, that derived the so-called Maxwell-Boltzmann canonical probability. Given the zero boundary condition black box, Planck solved a discrete standing wave eigenstates (equation). Together with the canonical partition function (equation) an average ensemble average of all possible internal energy yielded the celebrated Planck radiation spectral (equation) where the density of states (equation). In summary, given the multispectral sensing data (equation), we applied Lagrange Constraint Neural Network (LCNN) to solve the Blind Sources Separation (BSS) for a set of equivalent bb target temperatures. From the measurements of specific value, slopes and shapes we can fit a set of Kelvin temperatures T's for each bb targets. As a result, we could apply the analytical continuation for each entropy sources along the temperature-unique Planck spectral curves always toward the RGB color temperature display for any sensing probing frequency.

  16. Material and technology trends in fiber optics

    Science.gov (United States)

    Schuster, Kay; Unger, Sonja; Aichele, Claudia; Lindner, Florian; Grimm, Stephan; Litzkendorf, Doris; Kobelke, Jens; Bierlich, Jörg; Wondraczek, Katrin; Bartelt, Hartmut

    2014-08-01

    The increasing fields of applications for modern optical fibers present great challenges to the material properties and the processing technology of fiber optics. This paper gives an overview of the capabilities and limitations of established vapor deposition fiber preform technologies, and discusses new techniques for improved and extended doping properties in fiber preparation. In addition, alternative fabrication technologies are discussed, such as a powder-based process (REPUSIL) and an optimized glass melting method to overcome the limits of conventional vapor deposition methods concerning the volume fabrication of rare earth (RE)-doped quartz and high silica glasses. The new preform technologies are complementary with respect to enhanced RE solubility, the adjustment of nonlinear fiber properties, and the possibility of hybrid fiber fabrication. The drawing technology is described based on the requirements of specialty fibers such as adjusted preform and fiber diameters, varying coating properties, and the microstructuring of fiber configurations as low as in the nanometer range.

  17. Optical Fiber Embedded in Epoxy Glass Unidirectional Fiber Composite System

    Directory of Open Access Journals (Sweden)

    Irina Severin

    2013-12-01

    Full Text Available We aimed to embed silica optical fibers in composites (epoxy vinyl ester matrix reinforced with E-glass unidirectional fibers in mass fraction of 60% in order to further monitor the robustness of civil engineering structures (such as bridges. A simple system was implemented using two different silica optical fibers (F1—double coating of 172 µm diameter and F2—single coating of 101.8 µm diameter respectively. The optical fibers were dynamically tensile tested and Weibull plots were traced. Interfacial adhesion stress was determined using pull-out test and stress values were correlated to fracture mechanisms based on SEM observations. In the case of the optical fiber (OF (F1/resin system and OF (F1/composite system, poor adhesion was reported that may be correlated to interface fracture at silica core level. Relevant applicable results were determined for OF (F2/composite system.

  18. Optical properties of curing epoxies and applications to the fiber optic composite cure sensor

    Science.gov (United States)

    Afromowitz, Martin A.; Lam, Kai-Yuen

    1990-02-01

    An account is given of a fiber-optic technique for the in situ determination of a thermosetting polymer's cure-endpoint which requires no calibration. The technique involves (1) preparation and full cure of a short sensing-fiber element from the thermosetting resin in question; (2) the embedding of the fiber element within the panel during layup; (3) the joining of multimode silica fibers to each end of the sensing fiber in such a way that they extend beyond the panel that is to be cured; and (4) transmission of LED near-IR light through the fiber arrangement, in order to measure the intensity of the transmitted light with a photodetector. Because the fully cured resin has a greater refractive index than the uncured or partially cured resin, it acts as an efficient waveguide whose numerical aperture varies over the course of cure, decaying to zero transmission at conclusion of the curing process.

  19. Nanoparticle-doped radioluminescent silica optical fibers

    Science.gov (United States)

    Mrazek, J.; Nikl, M.; Kasik, I.; Podrazky, O.; Aubrecht, J.; Beitlerova, A.

    2014-05-01

    This contribution deals with the preparation and characterization of the silica optical fibers doped by nanocrystalline zinc silicate. The sol-gel approach was employed to prepare colloidal solution of zinc silicate precursors. Prepared sol was thermally treated to form nanocrystalline zinc silicate disperzed inside amorphous silica matrix or soaked inside the porous silica frit deposed inside the silica substrate tube which was collapsed into preform and drawn into optical fiber. Single mode optical fiber with the core diameter 15 ?m and outer diamer 125 ?m was prepared. Optical and waveguiding properties of the fiber were analyzed. Concentration of the zinc silicate in the fiber was 0.93 at. %. Radioluminescence properties of nanocrystalline zinc silicate powder and of the prepared optical fiber were investigated. The nanoparticle doped samples appear a emission maximum at 390 nm.

  20. Grazing incidence angle based sensing approach integrated with fiber-optic Fourier transform infrared (FO-FTIR) spectroscopy for remote and label-free detection of medical device contaminations

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Moinuddin, E-mail: moinuddin.hassan@fda.hhs.gov; Ilev, Ilko [Optical Therapeutics and Medical Nanophotonics Laboratory, Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland 20993 (United States)

    2014-10-15

    Contamination of medical devices has become a critical and prevalent public health safety concern since medical devices are being increasingly used in clinical practices for diagnostics, therapeutics and medical implants. The development of effective sensing methods for real-time detection of pathogenic contamination is needed to prevent and reduce the spread of infections to patients and the healthcare community. In this study, a hollow-core fiber-optic Fourier transform infrared spectroscopy methodology employing a grazing incidence angle based sensing approach (FO-FTIR-GIA) was developed for detection of various biochemical contaminants on medical device surfaces. We demonstrated the sensitivity of FO-FTIR-GIA sensing approach for non-contact and label-free detection of contaminants such as lipopolysaccharide from various surface materials relevant to medical device. The proposed sensing system can detect at a minimum loading concentration of approximately 0.7 ?g/cm{sup 2}. The FO-FTIR-GIA has the potential for the detection of unwanted pathogen in real time.

  1. Grazing incidence angle based sensing approach integrated with fiber-optic Fourier transform infrared (FO-FTIR) spectroscopy for remote and label-free detection of medical device contaminations

    International Nuclear Information System (INIS)

    Contamination of medical devices has become a critical and prevalent public health safety concern since medical devices are being increasingly used in clinical practices for diagnostics, therapeutics and medical implants. The development of effective sensing methods for real-time detection of pathogenic contamination is needed to prevent and reduce the spread of infections to patients and the healthcare community. In this study, a hollow-core fiber-optic Fourier transform infrared spectroscopy methodology employing a grazing incidence angle based sensing approach (FO-FTIR-GIA) was developed for detection of various biochemical contaminants on medical device surfaces. We demonstrated the sensitivity of FO-FTIR-GIA sensing approach for non-contact and label-free detection of contaminants such as lipopolysaccharide from various surface materials relevant to medical device. The proposed sensing system can detect at a minimum loading concentration of approximately 0.7 ?g/cm2. The FO-FTIR-GIA has the potential for the detection of unwanted pathogen in real time

  2. Interferometric microstructured polymer optical fiber ultrasound sensor for optoacoustic endoscopic imaging in biomedical applications

    DEFF Research Database (Denmark)

    Gallego, Daniel; Sáez-Rodríguez, David

    2014-01-01

    We report a characterization of the acoustic sensitivity of microstructured polymer optical fiber interferometric sensors at ultrasonic frequencies from 100kHz to 10MHz. The use of wide-band ultrasonic fiber optic sensors in biomedical ultrasonic and optoacoustic applications is an open alternative to conventional piezoelectric transducers. These kind of sensors, made of biocompatible polymers, are good candidates for the sensing element in an optoacoustic endoscope because of its high sensitivity, its shape and its non-brittle and non-electric nature. The acoustic sensitivity of the intrinsic fiber optic interferometric sensors depends strongly of the material which is composed of. In this work we compare experimentally the intrinsic ultrasonic sensitivities of a PMMA mPOF with other three optical fibers: a singlemode silica optical fiber, a single-mode polymer optical fiber and a multimode graded-index perfluorinated polymer optical fiber. © 2014 SPIE.

  3. Welding-fume-induced transmission loss in tapered optical fibers

    Science.gov (United States)

    Yi, Ji-Haeng

    2015-09-01

    This paper presents a method for sensing welding fumes in real time. This method is based on the results of nanoparticle-induced optical-fiber loss experiments that show that the losses are determined by the nanoparticle density and the taper waist. The tapered fiber is obtained by applying heat radiated from hot quartz, and monitoring is done in real time. First, the durability of the tapered fiber during the welding process is proven. Then, the loss is categorized by using the sizes of welding fume particles. The sensitivity to welding fumes increases with increasing size of the particles; consequently, the dimension of the taper waist decreases.

  4. Online fiber-optic spectrophotometry

    Energy Technology Data Exchange (ETDEWEB)

    Van Hare, D.R.; O' Rourke, P.E.; Prather, W.S.

    1989-01-01

    The Savannah River Plant operates two radio-chemical separations areas to recover uranium and plutonium from nuclear reactor fuel and target assemblies. Chemical processes in these areas are controlled based on laboratory analysis of samples extracted from the process. While analytical results from the laboratory are reliable, the process of pulling samples, transporting them to the laboratory, analyzing them, and then reporting results is time consuming and potentially exposes many workers to highly radioactive solutions. To improve the timeliness of chemical information and reduce personnel radiation exposure, the Savannah River Laboratory has developed an online fiber optic spectrophotometer which combines three new technologies, fiber optics, diode array spectrophotometers, and multivariate data analysis. The analyzer monitors the uranium and nitrate concentration of seven aqueous process streams in a uranium purification process. The analyzer remotely controls the sampling of each process stream and monitors the relative flow rate through each sampler. Spectrophotometric data from the analyzer is processed by multivariate data analysis to give both uranium and nitrate concentrations as well as an indication of the quality of the data.

  5. Monitoring the Evaporation of Fluids from Fiber-Optic Micro-Cell Cavities

    OpenAIRE

    Borut Preloznik; Vlada Artel; Sukenik, Chaim N.; Denis Donlagic; Avi Zadok; Eyal Preter

    2013-01-01

    Fiber-optic sensors provide remote access, are readily embedded within structures, and can operate in harsh environments. Nevertheless, fiber-optic sensing of liquids has been largely restricted to measurements of refractive index and absorption spectroscopy. The temporal dynamics of fluid evaporation have potential applications in monitoring the quality of water, identification of fuel dilutions, mobile point-of-care diagnostics, climatography and more. In this work, the fiber-optic monitori...

  6. Brillouin Corrosion Expansion Sensors for Steel Reinforced Concrete Structures Using a Fiber Optic Coil Winding Method

    OpenAIRE

    Xingjun Lv; Jinping Ou; Jie Lu; Guofu Qiao; Peng Gong; Xuefeng Zhao

    2011-01-01

    In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. ...

  7. Optical Fiber LSPR Biosensor Prepared by Gold Nanoparticle Assembly on Polyelectrolyte Multilayer

    OpenAIRE

    Yunliang Shao; Shuping Xu; Xianliang Zheng; Ye Wang; Weiqing Xu

    2010-01-01

    This article provides a novel method of constructing an optical fiber localized surface plasmon resonance (LSPR) biosensor. A gold nanoparticle (NP) assembled film as the sensing layer was built on the polyelectrolyte (PE) multilayer modified sidewall of an unclad optical fiber. By using a trilayer PE structure, we obtained a monodisperse gold NP assembled film. The preparation procedure for this LSPR sensor is simple and time saving. The optical fiber LSPR sensor has higher sensitivity and o...

  8. Application of Fiber Optics and Compound Collectors

    Science.gov (United States)

    Fantone, S. D.

    1984-01-01

    The utilization of fiber optics and compound flux collectors as optical components in stellar photometers is discussed. Basic principles are outlined for such components and systems issues are addressed.

  9. Fiber-based distance sensing interferometry.

    Science.gov (United States)

    Thurner, Klaus; Quacquarelli, Francesca Paola; Braun, Pierre-François; Dal Savio, Claudio; Karrai, Khaled

    2015-04-01

    We present an interferometric displacement sensor based on a folded low-finesse Fabry-Perot cavity. The fiber-optic sensor uses a quadrature detection scheme based on the wavelength modulation of a DFB laser. This enables measuring position changes over a range of 1 m for velocities up to 2 m/s. The sensor is well suited to work in extreme environments such as ultrahigh vacuum, cryogenic temperatures, or high magnetic fields and supports multichannel applications. The interferometer achieves a repeatability of 0.44??nm(3?) at a working distance of 20 mm, a resolution of 1 pm, and an accuracy of 1 nm. PMID:25967221

  10. An optical fiber optofluidic particle aspirator

    Science.gov (United States)

    Murugan, Ganapathy S.; Belal, Mohammad; Grivas, Christos; Ding, Ming; Wilkinson, James S.; Brambilla, Gilberto

    2014-09-01

    A fiberized optofluidic particle trapping device based on a micro-slot fabricated in a standard single-mode optical fiber by femtosecond laser micromachining is demonstrated. While fluidic convective motions move a large number of microparticles into the slot, the optical mode propagating in the nearby optical fiber core is exploited to trap and propel the particles inside the slot, thereby facilitating their collection at one of the slot extremities. The combined effect of fluidic and optical trapping allows for the collection of particles from as far as 60 ?m away from the optical trap. Application to particle and live cell trapping and propulsion is demonstrated.

  11. Laser beam shaping inside an optical fiber

    International Nuclear Information System (INIS)

    Some laser applications like the injection line of powerful lasers requires a very uniform laser beam spatial profile. Such a profile is usually obtained by using expensive optic components that are difficult to align. A new solution consists of shaping the laser beam not in the open air but inside an optic fiber. We have created a micro-structured optic fiber whose propagation mode is not Gaussian as usual but is of a flattened shape. This optic fiber will replace the optic component dedicated to spatial shaping of the laser beam, this function is usually made by phase mirrors located in the first stage of the amplification process

  12. Laboratory Equipment Type Fiber Optic Refractometer

    Directory of Open Access Journals (Sweden)

    E. F. Carome

    2002-09-01

    Full Text Available Using fiber optics and micro optics technologies we designed aninnovative fiber optic index of refraction transducer that has uniqueproperties. On the base of this transducer a laboratory equipment typefiber optic refractometer was developed for liquid index of refractionmeasurements. Such refractometer may be used for medical,pharmaceutical, industrial fluid, petrochemical, plastic, food, andbeverage industry applications. For example, it may be used formeasuring the concentrations of aqueous solutions: as the concentrationor density of a solute increase, the refractive index increasesproportionately. The paper describes development work related to designof laboratory type fiber optic refractometer and describes experimentsto evaluation of its basic properties.

  13. Dynamic Characterization of Polymer Optical Fibers

    DEFF Research Database (Denmark)

    Stefani, Alessio; Andresen, Søren; Yuan, Wu; Bang, Ole

    2012-01-01

    With the increasing interest in fiber sensors based on polymer optical fibers, it becomes fundamental to determine the real applicability and reliability of this type of sensor. The viscoelastic nature of polymers gives rise to questions about the mechanical behavior of the fibers. In particular...

  14. Laboratory Equipment Type Fiber Optic Refractometer

    OpenAIRE

    E. F. Carome; M. Benca; L. Ovsenik; J. Turan

    2002-01-01

    Using fiber optics and micro optics technologies we designed aninnovative fiber optic index of refraction transducer that has uniqueproperties. On the base of this transducer a laboratory equipment typefiber optic refractometer was developed for liquid index of refractionmeasurements. Such refractometer may be used for medical,pharmaceutical, industrial fluid, petrochemical, plastic, food, andbeverage industry applications. For example, it may be used formeasuring the concentrations of aqueou...

  15. Development of smart textiles with embedded fiber optic chemical sensors

    Science.gov (United States)

    Khalil, Saif E.; Yuan, Jianming; El-Sherif, Mahmoud A.

    2004-03-01

    Smart textiles are defined as textiles capable of monitoring their own health conditions or structural behavior, as well as sensing external environmental conditions. Smart textiles appear to be a future focus of the textile industry. As technology accelerates, textiles are found to be more useful and practical for potential advanced technologies. The majority of textiles are used in the clothing industry, which set up the idea of inventing smart clothes for various applications. Examples of such applications are medical trauma assessment and medical patients monitoring (heart and respiration rates), and environmental monitoring for public safety officials. Fiber optics have played a major role in the development of smart textiles as they have in smart structures in general. Optical fiber integration into textile structures (knitted, woven, and non-woven) is presented, and defines the proper methodology for the manufacturing of smart textiles. Samples of fabrics with integrated optical fibers were processed and tested for optical signal transmission. This was done in order to investigate the effect of textile production procedures on optical fiber performance. The tests proved the effectiveness of the developed methodology for integration of optical fibers without changing their optical performance or structural integrity.

  16. Optical fiber accelerometer based on MEMS torsional micromirror

    Science.gov (United States)

    Zeng, Fanlin; Zhong, Shaolong; Xu, Jing; Wu, Yaming

    2008-03-01

    A novel structure of optical fiber accelerometer based on MEMS torsional micro-mirror is introduced, including MEMS torsional micro-mirror and optical signal detection. The micro-mirror is a non-symmetric one, which means that the torsional bar supporting the micro-mirror is not located in the axis where the center of the micro-mirror locates. The optical signal detection is composed of PIN diode and dual fiber collimator, which is very sensitive to the coupling angle between the input fiber and output fiber. The detection principle is that acceleration is first transformed into torsional angle of the micro-mirror, then, optical insertion loss of the dual fiber collimator caused by the angle can be received by PIN. So under the flow of acceleration to torsional angle to optical signal attenuation to optical power detection, the acceleration is detected. The theory about sensing and optical signal detect of the device are discussed in this paper. The sensitive structure parameters and performance parameters are calculated by MATLAB. To simulate the static and modal analysis, the finite element analysis, ANSYS, is employed. Based on the above calculation, several optimization methods and the final structure parameters are given. The micro-mirror is completed by using silicon-glass bonding and deep reactive ion etching (DRIE). In the experiment, the acceleration is simulated by electrostatic force and the test results show that the static acceleration detection agrees with the theory analysis very well.

  17. Recent advances toward a fiber optic sensor for nerve agent

    Science.gov (United States)

    Beshay, Manal; Cordero, Steven R.; Mukamal, Harold; Ruiz, David; Lieberman, Robert A.

    2008-04-01

    We report advances made on the development of a fiber optic nerve agent sensor having its entire length as the sensing element. Upon exposure to sarin gas or its simulant, diisopropyl fluorophosphate, the cladding changes color resulting in an alteration of the light intensity throughput. The optical fiber is multimode and consists of a fused-silica core and a nerve agent sensitive cladding. The absorption characteristics of the cladding affect the fiber's spectral attenuation and limit the length of light guiding fiber that can be deployed continuously. The absorption of the cladding is also dependent on the sensor formulation, which in turn influences the sensitivity of the fiber. In this paper, data related to the trade-off of sensitivity, spectral attenuation, and length of fiber challenged will be reported. The fiber is mass produced using a conventional fiber optic draw tower. This technology could be used to protect human resources and buildings from dangerous chemical attacks, particularly when large areas or perimeters must be covered. It may also be used passively to determine how well such areas have been decontaminated.

  18. Normal And Surface-Enhanced Raman Scattering With Optical Fibers

    Science.gov (United States)

    Myrick, Michael L.; Angel, S. M.

    1990-02-01

    Raman scattering techniques, because of the vibrational information they contain, have numerous applications in the measurement and identification of aqueous pollutants in groundwater, as well as other contaminated waters. However, the extension of Raman techniques using fiber optics to remote sensing of groundwater is not completely straightforward. Single-fiber optrodes provide the greatest signals but also large background levels. Multiple-fiber optrodes offer lower background levels but are not practical over very long distances and are not as sensitive as single-fiber optrodes. The difficulties of obtaining Raman spectra with fiber optics are discussed, and the potential techniques for overcoming the limitations of single-fiber devices are descrivbed. The results of Raman spectral measurements that were made using a dual-fiber optrode in a novel forward-scattering configuration will be presented. The possible extension of these results to surface-enhanced Raman (SER) scattering will be discussed. In addition initial results of SERS performed with optical fibers will be presented, along with a description of future directions for this research.

  19. Optical fiber sensors for harsh environments

    Science.gov (United States)

    Xu, Juncheng; Wang, Anbo

    2007-02-06

    A diaphragm optic sensor comprises a ferrule including a bore having an optical fiber disposed therein and a diaphragm attached to the ferrule, the diaphragm being spaced apart from the ferrule to form a Fabry-Perot cavity. The cavity is formed by creating a pit in the ferrule or in the diaphragm. The components of the sensor are preferably welded together, preferably by laser welding. In some embodiments, the entire ferrule is bonded to the fiber along the entire length of the fiber within the ferrule; in other embodiments, only a portion of the ferrule is welded to the fiber. A partial vacuum is preferably formed in the pit. A small piece of optical fiber with a coefficient of thermal expansion chosen to compensate for mismatches between the main fiber and ferrule may be spliced to the end of the fiber.

  20. Silver metaphosphate glass wires inside silica fibers-a new approach for hybrid optical fibers.

    Science.gov (United States)

    Jain, Chhavi; Rodrigues, Bruno P; Wieduwilt, Torsten; Kobelke, Jens; Wondraczek, Lothar; Schmidt, Markus A

    2016-02-22

    Phosphate glasses represent promising candidates for next-generation photonic devices due to their unique characteristics, such as vastly tunable optical properties, and high rare earth solubility. Here we show that silver metaphosphate wires with bulk optical properties and diameters as small as 2 µm can be integrated into silica fibers using pressure-assisted melt filling. By analyzing two types of hybrid metaphosphate-silica fibers, we show that the filled metaphosphate glass has only negligible higher attenuation and a refractive index that is identical to the bulk material. The presented results pave the way towards new fiber-type optical devices relying on metaphosphate glasses, which are promising materials for applications in nonlinear optics, sensing and spectral filtering. PMID:26906989

  1. Multimode Waveguide Devices For Fiber Optic Instrumentation

    Science.gov (United States)

    Boiarski, A. A.; Sriram, S.

    1988-12-01

    Multimode polymer waveguide circuit fabrication techniques were used to produce several low-cost devices applicable to fiber optic sensor instruments. A 2x1 coupler with 3% reference tap was constructed with 250 and 500 #m diameter plastic fiber pigtails. This coupler had a 2 dB excess loss and could be used to replace the bulk-optic, 3 dB beamsplitter in a fiber optic instrumentation package. Further, a miniature fiber-tipped pressure sensor was produced using waveguide circuit-based photofabrication principles. This device could provide a disposable, catheter-tipped sensor for blood pressure monitoring.

  2. Radiation cured coatings for fiber optics

    International Nuclear Information System (INIS)

    A continuous protective coating is formed on a fiber optic by coating the fiber optic in a bath of a liquid radiation curable composition at a temperature up to 900C and exposing the coated conductor to ultraviolet or high energy ionizing radiation to cure the coating

  3. Fiber-optic liquid level sensor

    Science.gov (United States)

    Weiss, Jonathan D. (Albuquerque, NM)

    1991-01-01

    A fiber-optic liquid level sensor measures the height of a column of liquid through the hydrostatic pressure it produces. The sensor employs a fiber-optic displacement sensor to detect the pressure-induced displacement of the center of a corrugated diaphragm.

  4. A microstructured Polymer Optical Fiber Biosensor

    DEFF Research Database (Denmark)

    Emiliyanov, Grigoriy Andreev; Jensen, Jesper Bo; Hoiby, Poul E.; Bang, Ole; Pedersen, Lars H.

    2006-01-01

    We demonstrate selective detection of fluorophore labeled antibodies from minute samples probed by a sensor layer of the complementary biomolecules immobilized inside the air holes of microstructured Polymer Optical Fibers.......We demonstrate selective detection of fluorophore labeled antibodies from minute samples probed by a sensor layer of the complementary biomolecules immobilized inside the air holes of microstructured Polymer Optical Fibers....

  5. Optical fiber biosensor based on multiple total internal reflections in heterodyne interferometry

    Science.gov (United States)

    Wang, Shinn-Fwu; Chiu, Jyh-Shyan; Wang, Ming-Jen

    2007-07-01

    In this paper, an optical fiber biosensor based on multiple total internal reflections in heterodyne interferometry is proposed. The sensor is made of a long U-shaped multimode optical fiber which cladding is removed from the sensing portion of the fiber. With the optical fiber biosensor the phase shift difference due to the multiple total internal reflections (MTIR) effect between the P and S-polarizations is measured by using heterodyne interferometry with the optical fiber biosensor. Substituting the phase shift difference into Fresnel's equations, the refractive index for the tested medium can be calculated. The resolution of the sensor can reach 1.58×10 -6 refractive index unit (RIU). The optical fiber biosensor could be valuable for chemical, biological and biochemical sensing. It has some merits, such as, high resolution and stability, small size and real-time measurement.

  6. Tunable Laser Development for In-flight Fiber Optic Based Structural Health Monitoring Systems

    Science.gov (United States)

    Richards, Lance; Parker, Allen; Chan, Patrick

    2014-01-01

    The objective of this task is to investigate, develop, and demonstrate a low-cost swept lasing light source for NASA DFRC's fiber optics sensing system (FOSS) to perform structural health monitoring on current and future aerospace vehicles. This is the regular update of the Tunable Laser Development for In-flight Fiber Optic Based Structural Health Monitoring Systems website.

  7. Radiation resistance of the optical fiber

    International Nuclear Information System (INIS)

    Recently attention is paid to the radiation resistance, especially the increment in transmission loss, of the optical fiber. That is, the loss increment after its use under low dose rate for 20 years - 25 years is estimated for the purpose of design of the system. In the optical fiber having a Ge doped quartz core without metallic impurities, the loss increment is known to be dependent on the dose rate similarly to the case of pure quartz. The loss increment of this optical fiber was estimated for the extended exposure at low dose rate. The loss increment in the wholly-synthetic, Ge doped core, optical fiber is negligibly small; its initial loss is small and it is in a high band. The optical fiber is thus widely applicable for the system under radiation requiring large-capacity transmission. (Mori, K.)

  8. Power system applications of fiber optics

    Science.gov (United States)

    Kirkham, H.; Johnston, A.; Lutes, G.; Daud, T.; Hyland, S.

    1984-01-01

    Power system applications of optical systems, primarily using fiber optics, are reviewed. The first section reviews fibers as components of communication systems. The second section deals with fiber sensors for power systems, reviewing the many ways light sources and fibers can be combined to make measurements. Methods of measuring electric field gradient are discussed. Optical data processing is the subject of the third section, which begins by reviewing some widely different examples and concludes by outlining some potential applications in power systems: fault location in transformers, optical switching for light fired thyristors and fault detection based on the inherent symmetry of most power apparatus. The fourth and final section is concerned with using optical fibers to transmit power to electric equipment in a high voltage situation, potentially replacing expensive high voltage low power transformers. JPL has designed small photodiodes specifically for this purpose, and fabricated and tested several samples. This work is described.

  9. Nanocrystalline samarium oxide coated fiber optic gas sensor

    International Nuclear Information System (INIS)

    Highlights: • This fiber optic gas sensor works at room temperature. • As-prepared and annealed Sm2O3 nanoparticles are act as sensor materials. • Sm2O3 clad modified fiber detect the ammonia, ethanol and methanol gases. • The response of evanescent wave loss has been studied for different concentrations. - Abstract: Nanocrystalline Sm2O3 coated fiber optic sensor is proposed for detecting toxic gases such as ammonia, methanol and ethanol vapors. Sm2O3 in the as prepared form as well as annealed form have been used as gas sensing materials, by making them as cladding of a PMMA fiber. The spectral characteristics of the Sm2O3 gas sensor are presented for ammonia, methanol and ethanol gases with different concentrations ranging from 0 to 500 ppm. The sensor exhibits a linear variation in the output light intensity with the concentration. The enhanced gas sensitivity and selectivity of the sensor for ethanol is discussed briefly

  10. Metal-Coated Optical Fibers for High Temperature Applications

    Science.gov (United States)

    Zeakes, Jason; Murphy, Kent; Claus, Richard; Greene, Jonathan; Tran, Tuan

    1996-01-01

    This poster will highlight on-going research at the Virginia Tech Fiber & Electro-Optics Research Center (FEORC) in the area of thin films on optical fibers. Topics will include the sputter deposition of metals and metal; alloys onto optical fiber and fiber optic sensors for innovative applications. Specific information will be available on thin film fiber optic hydrogen sensors, corrosion sensors, and metal-coated optical fiber for high temperature aerospace applications.

  11. Utilizing simple FBG-based erbium-doped fiber architecture for remote temperature sensing

    Science.gov (United States)

    Yeh, C. H.; Chow, C. W.; Chen, J. Y.; Chen, H. Z.; Chen, J. H.; Liu, W. F.

    2015-10-01

    In this work, we demonstrate experimentally an erbium-doped fiber (EDF) ring laser structure for remote temperature sensing by using fiber Bragg gratings (FBGs) in C-band. Based on the proposed EDF laser configuration, the remote temperature sensing distance is achieved at 50 km. Here, ten FBGs are employed at the remote side for temperature sensing. By tuning the optical tunable filter (TF), the corresponding Bragg wavelength from each FBG can be monitored in the proposed EDF laser. As a result, in the temperature range from 20 to 82 °C, the maximum drift of Bragg wavelength can be detected at 0.84?nm.

  12. Fiber optic D dimer biosensor

    Science.gov (United States)

    Glass, Robert S. (Livermore, CA); Grant, Sheila A. (Pleasanton, CA)

    1999-01-01

    A fiber optic sensor for D dimer (a fibrinolytic product) can be used in vivo (e.g., in catheter-based procedures) for the diagnosis and treatment of stroke-related conditions in humans. Stroke is the third leading cause of death in the United States. It has been estimated that strokes and stroke-related disorders cost Americans between $15-30 billion annually. Relatively recently, new medical procedures have been developed for the treatment of stroke. These endovascular procedures rely upon the use of microcatheters. These procedures could be facilitated with this sensor for D dimer integrated with a microcatheter for the diagnosis of clot type, and as an indicator of the effectiveness, or end-point of thrombolytic therapy.

  13. Fiber Optic Temperature Sensors for Thermal Protection Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Intelligent Fiber Optic Systems Corporation (IFOS) proposes an innovative fiber optic-based, multiplexable, highly ruggedized, integrated sensor system for...

  14. Characteristics of optical fibers to radiation

    International Nuclear Information System (INIS)

    Recently, various reports have been issued on the radiation resistivity of optical fibers. Many of them treated the examination on the increase of transmission loss and the recovery characteristics after stopping irradiation when ?- or X-ray, neutron or electron beam was irradiated to optical fibers. Lately, however, the theoretical studies which were focused to the optical bleaching effect and the change of glass structure were also presented. In this report, the radiation characteristics of the optical fibers employed for communication and control cables and the various phenomena which have been the problems in image guides and light guides are described. The optical fibers used for the experiment were the graded index fibers of Ge- and P-doped core, and the SI type fibers of OH-doped silica glass core and highly pure silica glass core. The increase of transmission loss was measured on these fibers of 15 to 100 m length. For communication and control optical fibers, the loss was determined by the amount of dose, and did not depend on dose rate in GI type, but the loss depended on both dose and dose rate in SI type. For the optical fibers employed for image and light guides, in addition to the increase of loss by irradiation, it is generally said that the generation of fluorescence from optical fibers should also be carefully investigated. When X-ray was irradiated to the fibers of silica glass core, the generation of fluorescence increased with the increase of dose. This suggests that the problems such as the increase of background due to fluorescence may occur when light guides and the like are used in radiation fields. (Wakatsuki, Y.)

  15. Honeywell FLASH fiber optic motherboard evaluations

    Science.gov (United States)

    Stange, Kent

    1996-10-01

    The use of fiber optic data transmission media can make significant contributions in achieving increasing performance and reduced life cycle cost requirements placed on commercial and military transport aircraft. For complete end-to-end fiber optic transmission, photonics technologies and techniques need to be understood and applied internally to the aircraft line replaceable units as well as externally on the interconnecting aircraft cable plant. During a portion of the Honeywell contribution to Task 2A on the Fly- by-Light Advanced System Hardware program, evaluations were done on a fiber optic transmission media implementation internal to a Primary Flight Control Computer (PFCC). The PFCC internal fiber optic transmission media implementation included a fiber optic backplane, an optical card-edge connector, and an optical source/detector coupler/installation. The performance of these optical media components were evaluated over typical aircraft environmental stresses of temperature, vibration, and humidity. These optical media components represent key technologies to the computer end-to-end fiber optic transmission capability on commercial and military transport aircraft. The evaluations and technical readiness assessments of these technologies will enable better perspectives on productization of fly-by-light systems requiring their utilizations.

  16. Long distance fiber-optic displacement sensor based on fiber collimator

    International Nuclear Information System (INIS)

    A simple fiber-optic displacement sensor based on reflective intensity modulated technology is demonstrated using a fiber collimator. The sensing range is over 30 cm, which is over 100 times that of the conventional fiber-optic displacement sensor based on the normal single-mode fiber. The measured data are fitted into linear equation very well and the values of R-square are more than 0.995. The sensitivity of the device achieves 0.426 dB/cm over the range of 5-30 cm. By applying the relative technique, the errors resulted from the fluctuation of light source and influences of environment are effectively eliminated, and the stability for wide range measurement can be improved. The simplicity of the design, high dynamic range, stability and the ease of the fabrication make it suitable for applications in industries.

  17. Feasibility Study on Fiber-optic Radiation Sensor for Remote Gamma-ray Spectroscopy

    International Nuclear Information System (INIS)

    In this study, we fabricated a fiber-optic radiation sensor using an optical fiber and various scintillators. To select an adequate inorganic scintillator for the sensing probe of fiber-optic radiation sensor, 5 types of scintillators were evaluated. The spectra of gamma-rays emitted from a Na-22 radiation source were measured by using the manufactured sensors. As a result, the BGO was suitable for the sensing probe of fiber-optic radiation sensor due to its high scintillation output and exact photoelectric peak for the gamma-ray energy. The basic principle of radiation detection is to detect the signals caused by interactions between radiations and materials. There are various types of radiation detectors depending on types of radiation to be detected and physical quantities to be measured. As one of the radiation detectors, a fiber-optic radiation sensor using a scintillator and an optical fiber has two advantages such as no space restraint and remote sensing. Moreover, in nuclear environments, this kind of sensor has immunities for electromagnetic field, temperature, and pressure. Thus, the fiber-optic radiation sensor can be used in various fields including nondestructive inspection, radioactive waste management, nuclear safety, radiodiagnosis and radiation therapy. As a fundamental study of the fiber-optic radiation sensor for remote gamma-ray spectroscopy, in this study, we fabricated a fiber-optic radiation sensor using an optical fiber and various scintillators. To select an adequate inorganic scintillator for the sensing probe of fiber-optic radiation sensor, 5 types of scintillators were evaluated. The spectra of gamma-rays emitted from a Na-22 radiation source were measured by using the manufactured sensors

  18. MEMS based optical cross connects for fiber optical communication

    OpenAIRE

    Zickar, Michael; Rooij, Nico de

    2006-01-01

    MEMS based optical cross connects experience a growing market demand. They are used in optical fiber networks as well as optical measurement systems where they add functionality or increase the performance of the systems. 2x2 MEMS optical cross connects proved excellent performance and large optical cross connects with over 100 input and output channels are used to route the worldwide data traffic. However, large optical cross connects have a high cost. Medium sized optical cross connects hav...

  19. Curved Piezoelectric Actuators for Stretching Optical Fibers

    Science.gov (United States)

    Allison, Sidney G.; Shams, Qamar A.; Fox, Robert L.

    2008-01-01

    Assemblies containing curved piezoceramic fiber composite actuators have been invented as means of stretching optical fibers by amounts that depend on applied drive voltages. Piezoceramic fiber composite actuators are conventionally manufactured as sheets or ribbons that are flat and flexible, but can be made curved to obtain load-carrying ability and displacement greater than those obtainable from the flat versions. In the primary embodiment of this invention, piezoceramic fibers are oriented parallel to the direction of longitudinal displacement of the actuators so that application of drive voltage causes the actuator to flatten, producing maximum motion. Actuator motion can be transmitted to the optical fiber by use of hinges and clamp blocks. In the original application of this invention, the optical fiber contains a Bragg grating and the purpose of the controlled stretching of the fiber is to tune the grating as part of a small, lightweight, mode-hop-free, rapidly tunable laser for demodulating strain in Bragg-grating strain-measurement optical fibers attached to structures. The invention could also be used to apply controllable tensile force or displacement to an object other than an optical fiber.

  20. Method and apparatus for distributed sensing of volatiles using a long period fiber grating sensor with modulated plastic coating for environmental monitoring

    Science.gov (United States)

    Ponce, Adrian (Inventor); Kossakovski, Dmitri A. (Inventor); Bearman, Gregory H. (Inventor)

    2010-01-01

    Optical time domain reflectometry caused by absorption of a volatile or analyte into the fiber optic cladding is used as an optical nose. The fiber optics (14) are covered with a gas permeable film (44) which is patterned to leave millimeter wide gas permeable notches (48a-48d). The notches contain a sensing polymer that responds to different gases by expanding or contracting.