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 system

    Science.gov (United States)

    Adamovsky, Grigory (inventor)

    1991-01-01

    A fiber optic interferometer utilizes a low coherence light emitting diode (LED) laser as a light source which is filtered and driven at two RF frequencies, high and low, that are specific to the initial length of the resonator chamber. A displacement of a reflecting mirror changes the length traveled by the nonreferencing signal. The low frequency light undergoes destructive interference which reduces the average intensity of the wave while the high frequency light undergoes constructive interference which increases the average intensity of the wave. The ratio of these two intensity measurements is proportional to the displacement incurred.

  4. Optical fiber 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 installations via optical fiber cables at distances up to one kilometer. The applications include: Sampling of remote locations; Multipoint sampling with single instrument; Measurements in inaccessible locations; Coping with aggressive environments; Avoiding contamination; and Continuous monitoring

  5. 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.

  6. Instrumentation for remote sensing over fiber optics

    International Nuclear Information System (INIS)

    The authors developed a way to extend the sensing and analytical abilities of the laser fluorescence spectrometer beyond the physical confines of the laboratory by means of communications-grade optical fibers. These fiber probes are extremely rugged, compared with sensitive laboratory equipment, and also extremely inexpensive. They make it possible to perform sensitive chemical analyses in hostile environments without risking damage to the laser and the spectrometer. They have begun development of a remote analyzer for monitoring rare-earth-ion migration in a nuclear-waste repository, an environment too hostile for any previous remote sensing device. They are also developing optrodes sensitive to a wide variety of non-chemical stimuli

  7. Application of Optical Fiber Sensing Technology to Ground Deformation Measurement

    International Nuclear Information System (INIS)

    A new method of applying optic fiber sensor to high accurate ground deformation measurement, which is based on the idea about the optic fiber interference combined with fiber grating and the utilization of the characteristics of Bragg wavelength absolute measurement and high accurate relative measurement with fiber interference, is proposed. This sensing system has many advantages, such as anti-interference, corrosion resistance, moisture proof, no zero drift and no need of calibration.

  8. Fiber optic sensing technology: emerging markets and trends

    Science.gov (United States)

    Huff, David B.; Lebby, Michael S.

    2007-07-01

    Recent technical advances in fiber optic sensor technology have brought fiber sensors into the mainstream. Using a wide variety of sensing elements, and interrogation techniques, these devices are finding applications in fields from power line management to homeland security. A variety of fiber sensor technologies, applications, and markets are discussed.

  9. Fiber Optic-Based Refractive Index Sensing at INESC Porto

    OpenAIRE

    Orlando Frazão; José L. Santos; Gaspar Rego; Baptista, José M.; Diana Viegas; Paulo Caldas; Luis Coelho; Paula Tafulo; Silva, Susana O.; Carlos Gouveia; Jorge, Pedro A. S.

    2012-01-01

    A review of refractive index measurement based on different types of optical fiber sensor configurations and techniques is presented. It addresses the main developments in the area, with particular focus on results obtained at INESC Porto, Portugal. The optical fiber sensing structures studied include those based on Bragg and long period gratings, on micro-interferometers, on plasmonic effects in fibers and on multimode interference in a large spectrum of standard and microstructured optical ...

  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. 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.

  12. 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.

  13. 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.

  14. Low cost fiber optic sensing of sugar solution

    Science.gov (United States)

    Muthuraju, M. E.; Patlolla, Anurag Reddy; Vadakkapattu Canthadai, Badrinath; Pachava, Vengalrao

    2015-03-01

    The demand for highly sensitive and reliable sensors to assess the refractive index of liquid get many applications in chemical and biomedical areas. Indeed, the physical parameters such as concentration, pressure and density, etc., can be found using the refractive index of liquid. In contrast to the conventional refractometer for measurement, optical fiber sensor has several advantages like remote sensing, small in size, low cost, immune to EMI etc., In this paper we have discussed determination of refractive index of sugar solution using optical fiber. An intensity modulated low cost plastic fiber optic refractive index sensor has been designed for the study. The sensor is based on principle of change in angle of reflected light caused by refractive index change of the medium surrounding the fiber. The experimental results obtained for the sugar solution of different refractive indices prove that the fiber optic sensor is cable of measuring the refractive indices as well as the concentrations.

  15. 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

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

    OpenAIRE

    Chin, Sanghoon; The?venaz, 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.

  17. 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.

  18. Fiber optic shape sensing for monitoring of flexible structures

    Science.gov (United States)

    Lally, Evan M.; Reaves, Matt; Horrell, Emily; Klute, Sandra; Froggatt, Mark E.

    2012-04-01

    Recent advances in materials science have resulted in a proliferation of flexible structures for high-performance civil, mechanical, and aerospace applications. Large aspect-ratio aircraft wings, composite wind turbine blades, and suspension bridges are all designed to meet critical performance targets while adapting to dynamic loading conditions. By monitoring the distributed shape of a flexible component, fiber optic shape sensing technology has the potential to provide valuable data during design, testing, and operation of these smart structures. This work presents a demonstration of such an extended-range fiber optic shape sensing technology. Three-dimensional distributed shape and position sensing is demonstrated over a 30m length using a monolithic silica fiber with multiple optical cores. A novel, helicallywound geometry endows the fiber with the capability to convert distributed strain measurements, made using Optical Frequency-Domain Reflectometry (OFDR), to a measurement of curvature, twist, and 3D shape along its entire length. Laboratory testing of the extended-range shape sensing technology shows

  19. 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.

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

    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...

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

    Directory of Open Access Journals (Sweden)

    Ben Xu

    2014-08-01

    Full Text Available 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 nm/°C, which is over 250 times higher than its intrinsic sensitivity before sealing and significantly higher than that of a grating-based fiber sensors. The sensing mechanisms, including the incidental temperature-induced strain effect, are analyzed in detail both theoretically and experimentally. The liquid sealing technique is easy and low cost, and makes the sensor robust and insensitive to the surrounding refractive index. It can be applied to other fiber-optic refractometers for temperature sensing.

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

    Science.gov (United States)

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

    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 nm/°C, which is over 250 times higher than its intrinsic sensitivity before sealing and significantly higher than that of a grating-based fiber sensors. The sensing mechanisms, including the incidental temperature-induced strain effect, are analyzed in detail both theoretically and experimentally. The liquid sealing technique is easy and low cost, and makes the sensor robust and insensitive to the surrounding refractive index. It can be applied to other fiber-optic refractometers for temperature sensing. PMID:25123468

  3. Dielectric annular core fiber for optical sensing.

    Czech Academy of Sciences Publication Activity Database

    Sola?ík, P.; Burian, Z.; Kašík, Ivan; Mat?jec, Vlastimil; Mrázek, Jan; Hayer, Miloš

    Bellingham : SPIE -International Society for Optical Engineering, 2006 - (Culshaw, B.; Mignani, A.; Bartelt, H.; Jaroszewicz, L.), 61891R.1-61891R.9 ISBN 0-8194-6245-4. - (Proceedings of SPIE. 6189). [Photonics Europe. Strasbourg (FR), 03.04.2006-07.04.2006] R&D Projects: GA ?R(CZ) GA102/05/0948 Institutional research plan: CEZ:AV0Z2067918 Keywords : fibre optic sensorscapillarity Subject RIV: JB - Sensors, Measurment, Regulation

  4. Dielectric annular core fiber for optical sensing.

    Czech Academy of Sciences Publication Activity Database

    Sola?ík, P.; Burian, Z.; Kašík, Ivan; Mat?jec, Vlastimil; Mrázek, Jan; Hayer, Miloš

    Strasbourg : SPIE Europe, 2006. 215--. [Photonics Europe. 03.04.2006-07.04.2006, Strasbourg] R&D Projects: GA ?R(CZ) GA102/05/0948 Institutional research plan: CEZ:AV0Z20670512 Keywords : fibre optic sensors * capillarity * chemical analysis Subject RIV: JB - Sensors, Measurment, Regulation

  5. 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...

  6. 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...

  7. Enabling aspects of fiber optic acoustic sensing in harsh environments

    Science.gov (United States)

    Saxena, Indu F.

    2013-05-01

    The advantages of optical fiber sensing in harsh electromagnetic as well as physical stress environments make them uniquely suited for structural health monitoring and non-destructive testing. In addition to aerospace applications they are making a strong footprint in geophysical monitoring and exploration applications for higher temperature and pressure environments, due to the high temperature resilience of fused silica glass sensors. Deeper oil searches and geothermal exploration and harvesting are possible with these novel capabilities. Progress in components and technologies that are enabling these systems to be fieldworthy are reviewed and emerging techniques summarized that could leapfrog the system performance and reliability.

  8. Fiber-Optic Photoelastic Device Senses Pressure Of Hot Gas

    Science.gov (United States)

    Redner, Alex S.; Wesson, L. N.

    1995-01-01

    Fiber-optic/photoelastic device measures gas pressures up to 600 psi at operating temperatures as high as 1,100 degrees C. Pressure on fused-silica sensing element gives rise to birefringence via photoelastic effect. Polarization of light changed by birefringence; change in polarization measured and used to infer pressure causing it. Device prototype of gas-pressure sensor for aircraft engine. Mounted in engine at or near desired measurement point, where it responds to both time-varying and steady components of pressure.

  9. 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...

  10. CO2 laser ablation of bent optical fibers for sensing applications

    Science.gov (United States)

    Lévesque, L.; Jdanov, V.

    2011-01-01

    A procedure for the fabrication of a fiber optic sensor involving CO2 laser ablation at ? = 10.6 µm is proposed. A basic system to achieve optical fiber bending and material processing on a single mode optical fiber is described and it is demonstrated that an optical fiber can be bent at a very precise angle by focusing a CO2 beam locally near the glass cladding surface until it reaches melting temperature. A method is also described for removing material at the apex of a bent fiber to obtain a smooth and well flattened plane surface that is suitable for optical fiber sensing.

  11. 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.

  12. 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.

  13. 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.

  14. Frequency-shifted interferometry--a versatile fiber-optic sensing technique.

    Science.gov (United States)

    Ye, Fei; Zhang, Yiwei; Qi, Bing; Qian, Li

    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 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. PMID:24955943

  15. Brief history of fiber optic sensing in the oil field industry

    Science.gov (United States)

    Baldwin, Christopher S.

    2014-06-01

    The use of fiber optic sensing in the oil and gas industry has greatly expanded over the past two decades. Since the first optical fiber-based pressure sensor was installed in a well in 1993, the industry has sought to use fiber sensing technology to monitor in-well parameters. Through the years, optical fiber sensing has been used in an increasing number of applications as technical advances have opened the door for new measurements. Today, fiber optic sensors are used routinely to measure temperature throughout the wellbore. Optical sensors also provide pressure measurements at key locations within the well. These measurements are used to verify the integrity of the well, provide feedback during well completion operations, including the actuation of downhole valves, and to monitor the production or injection process. Other sensors, such as seismic monitors and flowmeters, use fiber sensing technology to make in-well measurements. Various optical sensing techniques are used to make these measurements, including Bragg grating, Raman scattering, and coherent Rayleigh scattering. These measurements are made in harsh environments, which require rugged designs for optical cable systems and instrumentation systems. Some of these applications have operating temperatures of 572°F (300°C), and other applications can have pressures in excess of 20,000 psi (1,379 bar). This paper provides a historical perspective on the use of fiber optic sensing in the oil and gas industry from industry firsts to current applications.

  16. Fiber Optic Distributed Temperature Sensing in Avalanche Research

    Science.gov (United States)

    Woerndl, Michaela; Tyler, S. W.; Hatch, C. E.; Dozier, J.; Prokop, A.

    2010-05-01

    Being a major driving force for snow metamorphism, thermal properties and temperature gradients in an alpine snow pack influence both, spatial distribution and temporal evolution of its stability throughout a winter season. In avalanche research and forecasting mainly weather station networks and models are employed for temperature-data collection and prediction. Standard temperature measurement devices used in weather stations and for model calibration typically provide point data over time. With fiber-optic Distributed Temperature Sensing (DTS) a laser is pulsed through standard telecommunications optical fibers of up to 30km in length, and uses the cables themselves as a thermometer. DTS allows for continuous observations of temperatures over large spatial scales and with high temporal resolution. Depending on the type of instrument, temperature readings can be provided every 0.25 to 2 meters along the cable and up to six times a minute. Measurement accuracies depend on integration times and can reach +/- 0.1 degrees C or better. Already well established in other environmental applications such as surface water - groundwater hydrology and soil moisture studies, this study assesses applicability and performance of DTS in snow environments and its potential benefits for avalanche research and forecasting. At the CRREL/UCSB research site on Mammoth Mountain, California, 40m fiber-optic cable loops were deployed at different depths in the snow pack to measure temperature and thermal gradient evolution over time and space. Four discrete measurement sessions of 4 to 20 days were conducted during the winter season 2008/2009. Strong horizontal spatial variability of temperatures of up to 3 degrees C within the snow pack over the 40m-sections were resolved. As expected, vertical thermal gradients were influenced by spatial location. Evolution of temperatures and gradients over time could be continuously monitored along the 40m transects during each measurement session. Instrument performance was affected by strongly varying ambient air temperatures, though resulting errors could be easily corrected during post processing. Specific demands when using a DTS system in a snow environment are discussed, as special care must be taken in instrument calibration, site and experimental design. Possible applications of a DTS system in avalanche research are presented.

  17. Spatially continuous distributed fiber optic sensing using optical carrier based microwave interferometry.

    Science.gov (United States)

    Huang, Jie; Lan, Xinwei; Luo, Ming; Xiao, Hai

    2014-07-28

    This paper reports a spatially continuous distributed fiber optic sensing technique using optical carrier based microwave interferometry (OCMI), in which many optical interferometers with the same or different optical path differences are interrogated in the microwave domain and their locations can be unambiguously determined. The concept is demonstrated using cascaded weak optical reflectors along a single optical fiber, where any two arbitrary reflectors are paired to define a low-finesse Fabry-Perot interferometer. While spatially continuous (i.e., no dark zone), fully distributed strain measurement was used as an example to demonstrate the capability, the proposed concept may also be implemented on other types of waveguide or free-space interferometers and used for distributed measurement of various physical, chemical and biological quantities. PMID:25089493

  18. 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 , 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)

  19. Calibration and deployment of a fiber-optic sensing system for monitoring debris flows.

    Science.gov (United States)

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

    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 includes a geophone or a microphone. Following confirmation of the reliability of the proposed sensing system, the fiber-optic sensing systems are deployed along the Ai-Yu-Zi and Chu-Shui Creeks in Nautou County of central Taiwan for monitoring debris flows. Sensitivity test of the deployed fiber-optic sensing system along the creek banks is also performed. Analysis results of the seismic data recorded by the systems reveal in detail the frequency characteristics of the artificially generated ground vibrations. Results of this study demonstrate that the proposed fiber-optic sensing system is highly promising for use in monitoring natural disasters that generate ground vibrations. PMID:22778616

  20. 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.

  1. 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)

  2. 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...

  3. 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.

  4. 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)

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

    OpenAIRE

    Zhu, P. Y.; Zhou, Y.; The?venaz, Luc; Jiang, G. L.

    2008-01-01

    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 rel...

  6. Structural Health Monitoring of Civil Infrastructure Using Optical Fiber Sensing Technology: A Comprehensive Review

    OpenAIRE

    X. W. Ye; Su, Y H; Han, J. P.

    2014-01-01

    In the last two decades, a significant number of innovative sensing systems based on optical fiber sensors have been exploited in the engineering community due to their inherent distinctive advantages such as small size, light weight, immunity to electromagnetic interference (EMI) and corrosion, and embedding capability. A lot of optical fiber sensor-based monitoring systems have been developed for continuous measurement and real-time assessment of diversified engineering structures such as b...

  7. 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.

  8. 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

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

    Directory of Open Access Journals (Sweden)

    Arafat Shabaneh

    2015-05-01

    Full Text Available 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 sensing layer are micro-characterized using FESEM and Raman spectroscopy techniques. When the developed sensor was exposed to different concentrations of ethanol (5% to 80%, the sensor reflectance reduced proportionally. The developed sensors showed high sensitivity, repeatability and fast responses (<55 s towards ethanol.

  10. 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

  11. 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.

  12. Optical Fiber Pipeline Data Compression based on Segment Sequential Compressed Sensing

    Directory of Open Access Journals (Sweden)

    HongJie Wan

    2013-01-01

    Full Text Available In distributed optical fiber pipeline pre-warning system, the sampling rate is very high for threatening event location, so vast data will be generated. Huge amount of data is inconvenient for transfer or storage. Because compressive sensing is a widely used methods for sampling and compressing data in the same time in recent years, this study adopts the compressive sensing approach to reduce the data quantity. In compressive sensing, the sparsity of each segment is important for signal recovery and it controls the measurement number needed for certain recovery accuracy of the recovered signal. The sparsity should be known in advance to determine the measurement number, but it is difficult to achieve. This is specially exemplified in optical fiber pipeline compressive sensing as the optical fiber pipeline data is longtime running data and the sparsity of every segment varies with time. In this study, the sequential approach joint with linear prediction is used to fix the measurement number of each segment. This approach further reduces the amount of data on the basis of compressive sensing. Simulation is carried out on the actual optical fiber pipeline pre-warning data and the experimental results show that the reconstruction SNR could exceed 26 dB.

  13. Use of nondestructive inspection and fiber optic sensing for damage characterization in carbon fiber fuselage structure

    Science.gov (United States)

    Neidigk, Stephen; Le, Jacqui; Roach, Dennis; Duvall, Randy; Rice, Tom

    2014-04-01

    To investigate a variety of nondestructive inspection technologies and assess impact damage characteristics in carbon fiber aircraft structure, the FAA Airworthiness Assurance Center, operated by Sandia National Labs, fabricated and impact tested two full-scale composite fuselage sections. The panels are representative of structure seen on advanced composite transport category aircraft and measured approximately 56"x76". The structural components consisted of a 16 ply skin, co-cured hat-section stringers, fastened shear ties and frames. The material used to fabricate the panels was T800 unidirectional pre-preg (BMS 8-276) and was processed in an autoclave. Simulated hail impact testing was conducted on the panels using a high velocity gas gun with 2.4" diameter ice balls in collaboration with the University of California San Diego (UCSD). Damage was mapped onto the surface of the panels using conventional, hand deployed ultrasonic inspection techniques, as well as more advanced ultrasonic and resonance scanning techniques. In addition to the simulated hail impact testing performed on the panels, 2" diameter steel tip impacts were used to produce representative impact damage which can occur during ground maintenance operations. The extent of impact damage ranges from less than 1 in2 to 55 in2 of interply delamination in the 16 ply skin. Substructure damage on the panels includes shear tie cracking and stringer flange disbonding. It was demonstrated that the fiber optic distributed strain sensing system is capable of detecting impact damage when bonded to the backside of the fuselage.

  14. Characterization of flexible copolymer optical fibers for force sensing applications.

    Science.gov (United States)

    Krehel, Marek; Rossi, René M; Bona, Gian-Luca; Scherer, Lukas J

    2013-01-01

    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. PMID:24021967

  15. 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.

  16. A plastic optical fiber sensor for the dual sensing of temperature and oxygen

    Science.gov (United States)

    Lo, Yu-Lung; Chu, Chen-Shane

    2008-04-01

    This study presents a low-cost plastic optical fiber sensor for the dual sensing of temperature and oxygen. The sensor features a commercially available epoxy glue coated on the side-polished fiber surface for temperature sensing and a fluorinated xerogel doped with platinum tetrakis pentrafluoropheny porphine (PtTFPP) coated on the fiber end for oxygen sensing. The temperature and oxygen indicators are both excited using a UV LED light source with a wavelength of 380 nm. The luminescence emission spectra of the two indicators are well resolved and exhibit no cross-talk effects. Overall, the results indicate that the dual sensor presented in this study provides an ideal solution for the non-contact, simultaneous sensing of temperature and oxygen in general biological and medical applications.

  17. [Development and application of six-channel fiber optic sensing drug dissolution monitor].

    Science.gov (United States)

    Yao, Jun; Shen, Jing; Li, Li; Li, Xin-Xia; Chen, Jian

    2014-09-01

    The drug dissolution test is an important examination of drug testing, which plays a very important role in the drug quality assessment. Automation and proceduring monitoring of drug dissolution can be implemented by the optical fiber sensing technology. Two modes of detection of UV-Vis absorption and fluorescence quenching were established by software implementation, with xenon lamp, deuterium lamp or halogen tungsten lamp as fluorescence, UV and visible light source, branch Y type optical fiber as light path transmission medium, UV-Vis probe and fluorescence molecular probe as light response devices, and CCD as detector. Optical fiber sensing drug dissolution monitor not only solves the current problems of time-consuming, and sampling of off-line analysis, but also provides real-time information of drug dissolution process. Thus, our study may provide a better evaluation method for the drug quality control. PMID:25532369

  18. 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.

  19. High sensitivity cascaded preamplifier with an optical bridge structure in Brillouin distributed fiber sensing system

    Science.gov (United States)

    Bi, Weihong; Lin, Hang; Fu, Xinghu; Fu, Guangwei

    2013-12-01

    Fiber amplifiers such as Erbium-doped fiber amplifier (EDFA) played a key role in developing long-haul transmission system and have been an important element for enabling the development of optical communication system. EDFA amplifies the optical signal directly, without the optical-electric-optical switch and has the advantages such as high gain, broad band, low noise figure. It is widely used in repeaterless submarine system, smart grid and community antenna television system. This article describe the application of optical-fiber amplifiers in distributed optical fiber sensing system, focusing on erbium-doped fiber preamplifiers in modern transmission optical systems. To enhance the measurement range of a spontaneous Brillouin intensity based distributed fiber optical sensor and improve the receiver sensitivity, a two cascaded EDFAs C-band preamplifier with an optical bridge structure is proposed in this paper. The first cascaded EDFA is consisted of a length of 4.3m erbium-doped fiber and pumped in a forward pump light using a laser operating at 975nm. The second one made by using a length of 16m erbium-doped fiber is pumped in a forward pump light which is the remnant pump light of the first cascaded EDFA. At the preamplifier output, DWDM, centered at the signal wavelength, is used to suppress unwanted amplified spontaneous emission. The experimental results show that the two cascade preamplifier with a bridge structure can be used to amplify for input Brillouin backscattering light greater than about -43dBm. The optical gain is characterized and more than 26dB is obtained at 1549.50nm with 300mW pump power.

  20. 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.

  1. 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)

  2. An improved fiber optic current sensing system for high frequency RF susceptibility measurements

    Science.gov (United States)

    Gibes, Susan; Jensen, Earl; Sun, Mei; Wickersheim, Kenneth

    1987-12-01

    A temperature sensing system has been developed as an alternative to the thin-film thermocouple system for the real-time measurement of high-frequency induced currents in the bridge wires of electroexplosive devices. The new temperature measurement technology uses as the sensing material a phosphor in contact with the conductor whose temperature is to be measured. An optical fiber is used to illuminate and interrogate the sensor. Since all the materials used in the sensor and fiber are electrically insulating, the technique does not perturb the system electromagnetically. Here, recent improvements to the measurement technique aimed at increasing its overall performance are reported together with preliminary results.

  3. Semiconductor Optical Amplifier (SOA-Fiber Ring Laser and Its Application to Stress Sensing

    Directory of Open Access Journals (Sweden)

    Yoshitaka Takahashi

    2011-12-01

    Full Text Available We have developed a novel optical fiber ring laser using a semiconductor optical amplifier (SOA as the gain medium, and taking advantage of polarization anisotropy of its gain. The frequency difference of the bi-directional laser is controlled by birefringence which is introduced in the ring laser cavity. The beat frequency generated by combining two counter-propagating oscillations is proportional to the birefringence, the fiber ring laser of the present study is, therefore, applicable to the fiber sensor. The sensing signal is obtained in a frequency domain with the material which causes the retardation change by a physical phenomenon to be measured. For the application to stress sensing, the present laser was investigated with a photoelastic material.

  4. 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.

  5. Sensing the earth crustal deformation with nano-strain resolution fiber-optic sensors.

    Science.gov (United States)

    Liu, Qingwen; He, Zuyuan; Tokunaga, Tomochika

    2015-06-01

    Crustal deformation measurement with a high resolution on the order of nano-strains in static to low frequency region is required for geophysical research. Optical fiber sensors are very attractive in this research field due to their unique advantages including high resolution, small size and easy deployment. In this paper, a fiber optic strain sensor with nano-strain-resolution and large measurement range for sensing the earth crustal deformation is reported. With this sensor the tide induced crustal deformation and the seismic wave were successfully recorded in field experiments. PMID:26072867

  6. 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.

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

    OpenAIRE

    Zhang Yan; Dhawan Anuj; Vo-Dinh Tuan

    2011-01-01

    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...

  8. 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...

  9. 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)

  10. 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.

  11. Fiber Optic Shape Sensing for Tethered Marsupial Rovers Project

    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...

  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 temnt 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. Mechanism analysis on biofouling detection based on optical fiber sensing technique

    Science.gov (United States)

    Ma, Huiping; Yuan, Feng; Liu, Yongmeng; Jiang, Xiuzhen

    2010-08-01

    More attention is paid to on-line monitoring of biofouling in industrial water process systems. Based on optical fiber sensing technology, biofouling detection mechanism is put forward in the paper. With biofouling formation, optical characteristics and the relation between light intensity and refractive index studied, schematic diagram of optical fiber self-referencing detecting system and technological flowchart are presented. Immunity to electromagnetic interference and other influencing factors by which the precision is great improved is also remarkable characteristic. Absorption spectrum of fluid medium molecule is measured by infrared spectrum and impurity is analyzed by character fingerprints of different liquid. Other pollutant source can be identified by means of infrared spectrum and arithmetic research of artificial neural networks (ANN) technology. It can be used in other fields such as mining, environment protection, medical treatment and transportation of oil, gas and water.

  14. 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.

  15. E-beam patterned gold nanodot arrays on optical fiber tips for localized surface plasmon resonance biochemical sensing.

    Science.gov (United States)

    Lin, Yongbin; Zou, Yang; Mo, Yuanyao; Guo, Junpeng; Lindquist, Robert G

    2010-01-01

    Electron beam lithography (EBL) was used to directly pattern periodic gold nanodot arrays on optical fiber tips. Localized surface plasmon resonance of the E-beam patterned gold nanodot arrays on optical fiber tips was utilized for biochemical sensing. The advantage of the optical fiber based localized surface plasmon resonance (LSPR) sensors is the convenience to work with and work in harsh environments. An optical fiber tip LSPR refractive index sensor of 196 nm per refractive index unit (RIU) sensitivity has been demonstrated. The affinity sensing property of the fiber tip sensor was demonstrated using biotin/streptavidin as the receptor/analyte. The detection limit for streptavidin was determined to be 6 pM. PMID:22163415

  16. E-Beam Patterned Gold Nanodot Arrays on Optical Fiber Tips for Localized Surface Plasmon Resonance Biochemical Sensing

    Directory of Open Access Journals (Sweden)

    Yongbin Lin

    2010-10-01

    Full Text Available Electron beam lithography (EBL was used to directly pattern periodic gold nanodot arrays on optical fiber tips. Localized surface plasmon resonance of the E-beam patterned gold nanodot arrays on optical fiber tips was utilized for biochemical sensing. The advantage of the optical fiber based localized surface plasmon resonance (LSPR sensors is the convenience to work with and work in harsh environments. An optical fiber tip LSPR refractive index sensor of 196 nm per refractive index unit (RIU sensitivity has been demonstrated. The affinity sensing property of the fiber tip sensor was demonstrated using biotin/streptavidin as the receptor/analyte. The detection limit for streptavidin was determined to be 6 pM.

  17. A hybrid fiber-optic sensing system for down-hole pressure and distributed temperature measurements

    Science.gov (United States)

    Chen, Ke; Zhou, Xinlei; Yang, Bokai; Peng, Wei; Yu, Qingxu

    2015-10-01

    A hybrid fiber-optic sensing technique, combining the extrinsic Fabry-Perot interferometer (EFPI) based pressure sensor with the incoherent optical frequency domain reflectometry (IOFDR) based distributed temperature sensor (DTS), is presented for down-hole measurements. By using a laser diode as the common light source, a highly integrated hybrid EFPI/DTS sensing system has been developed with a single fiber. With the injection current of the laser diode below lasing threshold, the broadband spontaneous emission light is used for EFPI based pressure sensing; while with the injection current above the threshold, the stimulated emission light is used for Raman based distributed temperature sensing. There is no overlap between the spectral range of the reflected light from the EFPI sensor and the spectral range of the Raman scattered light. Pressure and distributed temperature can thus be measured by using wavelength-division multiplexing (WDM) technology. Experimental results show that both the pressure and the distributed temperature are measured with little interference. Furthermore, the pressure measurement can be compensated by the measured temperature values.

  18. Fiber Optics

    Science.gov (United States)

    SFGate: SBC and Microsofthttp://sfgate.com/cgi-bin/article.cgi?file=/c/a/2004/06/23/MNGVR7AI711.DTLSBC Communications Inc.http://www.sbc.com/gen/press-room?pid=5838How Stuff Works: How Fiber Optics Workhttp://electronics.howstuffworks.com/fiber-optic.htmFiber Optic Reference Guide: A Brief Historyhttp://www.fiber-optics.info/fiber-history.htmPC World: Has Your Broadband Had Its Fiber?http://www.pcworld.com/news/article/0,aid,117684,00.aspTelephony Onlinehttp://telephonyonline.com/ar/telecom_breaking_meg_barrier/index.htmThis article from SFGate reports on the recent negotiations between SBC and Microsoft (1) and the implications of the new technology for Internet and television access. This website from SBC (2) provides video footage and background information on their initiative called Project Lightspeed. This initiative is based largely on fiber technology, which is described further on this website from How Stuff Works (3). This website (4) provides a brief history of fiber optics technology along with links to sections on the applications of fiber optics and more basics on transmission. This article from PC World (5) discusses how fiber optics became a viable option. This article from Telephony Online 6)reviews some of the challenges that remain.

  19. Environmental sensing with optical fiber sensors processed with focused ion beam and atomic layer deposition

    Science.gov (United States)

    Flores, Raquel; Janeiro, Ricardo; Dahlem, Marcus; Viegas, Jaime

    2015-03-01

    We report an optical fiber chemical sensor based on a focused ion beam processed optical fiber. The demonstrated sensor is based on a cavity formed onto a standard 1550 nm single-mode fiber by either chemical etching, focused ion beam milling (FIB) or femtosecond laser ablation, on which side channels are drilled by either ion beam milling or femtosecond laser irradiation. The encapsulation of the cavity is achieved by optimized fusion splicing onto a standard single or multimode fiber. The empty cavity can be used as semi-curved Fabry-Pérot resonator for gas or liquid sensing. Increased reflectivity of the formed cavity mirrors can be achieved with atomic layer deposition (ALD) of alternating metal oxides. For chemical selective optical sensors, we demonstrate the same FIB-formed cavity concept, but filled with different materials, such as polydimethylsiloxane (PDMS), poly(methyl methacrylate) (PMMA) which show selective swelling when immersed in different solvents. Finally, a reducing agent sensor based on a FIB formed cavity partially sealed by fusion splicing and coated with a thin ZnO layer by ALD is presented and the results discussed. Sensor interrogation is achieved with spectral or multi-channel intensity measurements.

  20. 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.

  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. Long period gratings in random hole optical fibers for refractive index sensing.

    Science.gov (United States)

    Wang, Ke; Pickrell, Gary

    2011-01-01

    We have demonstrated the fabrication of long period gratings in random hole optical fibers. The long period gratings are fabricated by a point-by-point technique using a CO(2) laser. The gratings with a periodicity of 450 ?m are fabricated and a maximum coupling efficiency of -9.81 dB has been achieved. Sensing of different refractive indices in the surrounding mediums is demonstrated by applying standard liquids with refractive indices from 1.400 to 1.440 to the long period grating. PMID:22319368

  3. Long Period Gratings in Random Hole Optical Fibers for Refractive Index Sensing

    Directory of Open Access Journals (Sweden)

    Gary Pickrell

    2011-01-01

    Full Text Available We have demonstrated the fabrication of long period gratings in random hole optical fibers. The long period gratings are fabricated by a point-by-point technique using a CO2 laser. The gratings with a periodicity of 450 µm are fabricated and a maximum coupling efficiency of ?9.81 dB has been achieved. Sensing of different refractive indices in the surrounding mediums is demonstrated by applying standard liquids with refractive indices from 1.400 to 1.440 to the long period grating.

  4. Ammonia sensing properties of tapered plastic optical fiber coated with silver nanoparticles/PVP/PVA hybrid

    Science.gov (United States)

    Rithesh Raj, D.; Prasanth, S.; Vineeshkumar, T. V.; Sudarsanakumar, C.

    2015-04-01

    A tapered plastic optical fiber gas sensor coated with silver nanoparticles/PVP/PVA hybrid is proposed for ammonia gas sensing application. The spectral characteristics of the gas sensor for different silver concentrations were studied at room temperature against various concentrations (0-500 ppm) of ammonia, methanol and ethanol. All the samples exhibited a linear decrease in spectral intensity with the increase in concentration of ammonia whereas it showed little effect for methanol and ethanol. Gas sensitivity studies revealed that the sensors exhibit higher sensitivity at higher concentrations of silver nanoparticles than at lower concentrations. The spectral characteristics of the sensor selectively represented its ammonia sensitivity.

  5. Long Period Gratings in Random Hole Optical Fibers for Refractive Index Sensing

    OpenAIRE

    Gary Pickrell; Ke Wang

    2011-01-01

    We have demonstrated the fabrication of long period gratings in random hole optical fibers. The long period gratings are fabricated by a point-by-point technique using a CO2 laser. The gratings with a periodicity of 450 µm are fabricated and a maximum coupling efficiency of ?9.81 dB has been achieved. Sensing of different refractive indices in the surrounding mediums is demonstrated by applying standard liquids with refractive indices from 1.400 to 1.440 to the long period grating.

  6. 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.

  7. 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, ...

  8. Soil moisture and flux sensing at 0.25-10,000 m scales using fiber optics

    Science.gov (United States)

    Selker, J. S.; Steele-Dunne, S.; Van De Giesen, N.; Ochsner, T.; Sayde, C.; Cosh, M. H.; Hatch, C. E.; Tyler, S. W.

    2011-12-01

    Fiber optic based temperature sensing has gained attention in the last 5 years for geophysical monitoring tasks. For hydrological applications, multi-scale observation of soil moisture and soil water is helpful to close the water balance and identify the processes that are controlling fluxes to the atmosphere and aquifers. In this paper we present the underlying concepts of fiber optic distributed temperature sensing (often referred to as DTS), as well as the current state of the art of this instrumentation (This resolution currently being, in degrees C, approximately 0.3 /(4Lt)^0.5 where L, >0.25m, is the interrogation interval; t is the sampling time in seconds, with a lower bound due to instrument stability of about 0.03 C). The measurement methods emphasized in this presentation will focus on actively heated cable (introduced in WRR doi:10.1029/2009WR007846) as obtained in the laboratory and Oklahoma MOISST field campaign. People interested in the technology can gain access for their research via the CTEMPs.org NSF facility, as well as contacting the lead author.

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

    Science.gov (United States)

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

    2014-10-15

    An unclad, multi-mode single crystal sapphire fiber was used as a platform, and immobilized colloidal Ag nanoparticles (NPs) were used as enabler, for evanescent-field fiber-optic sensing via surface-enhanced Raman scattering (SERS) of Rhodamine 6G (R6G) solution. The dependence of the measured Raman intensity on NP coverage density (to a maximum of 120??particles/?m²) as well as the coverage length (to a maximum of 6 cm) was investigated. We demonstrate the utility of SERS-active sapphire fibers for sensitive measurements (10?? M R6G). We further reveal, with the aid of theoretical analysis, that multi-mode fiber offers a significant advantage compared to its single-mode counterpart because the former allows two orders of magnitude higher particle coverage density than the latter to maximize SERS benefit, while maintaining the dominance of Raman gain despite the competitive interplay of NP-induced absorption and scattering loss along the interaction path length. PMID:25361094

  10. Selective deep wet etching of fused silica optical fibers for sensing applications

    Science.gov (United States)

    Krogulski, Krzysztof; ?mietana, Mateusz; Kwietniewski, Norbert; Król, Krystian

    2013-07-01

    In the paper we discuss crucial aspects of selective deep wet etching technology of fused silica optical fibers. The technology includes preparation of the fiber, photolithography aiming to create a mask for etching, wet etching process and photoresist removal. We also discuss the influence of removing polyimide layer from the fiber, photoresist type, thickness of the photoresist and etching time. The developed technology allows for obtaining periodic variations in the fiber diameter resulting in formation of corrugated long-period grating (LPG). Introduction of strain induces appearing of attenuation peak in the transmission spectrum of the fiber. The developed technology can be also applied for fabrication of other optical fiber devices.

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

    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...

  12. 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.

  13. 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

  14. A multi path, weather independent avalanche monitoring tool using distributed acoustic fiber optic sensing

    Science.gov (United States)

    Prokop, Alexander; Wirbel, Anna

    2013-04-01

    Information on avalanche activity is a paramount parameter in avalanche forecasting. When avalanches are released spontaneously, the risk of avalanches is very high. Triggering avalanches by artificial means, such as explosives launched from helicopter or avalanche towers, can also give information on the stability of the snow pack. Hence, monitoring of avalanches released naturally or artificially, is an important quantity in avalanche forecasting. This information is also needed when deciding whether to close or not endangered ski runs, roads or railway lines. So far monitoring systems lack certain benefits. Either they monitor only large avalanches, can only be used for single avalanche tracks or are weather/sight dependant. Therefore a new tool for avalanche- monitoring, a distributed fiber optic system, is for the first time installed and adapted for the purpose of monitoring snow avalanche activity. The method is based on an optical time domain reflectometer (OTDR) system, which dates back to the 1970`s and detects seismic vibrations and acoustic signals on a fiber optic cable that can have a length of up to 30 km. An appropriate test slope for this configuration has been found in the ski area of "Lech am Arlberg". In this work a detailed description of the theoretical background, the system implementation, the field installation, realization of tests and an investigation of the recorded data is presented. We conducted 100 tests and triggered 41 avalanches so far with a runout distances ranging from a few meters to approximately 250 meters, all of which were detected by the system, as well as the 59 not successful attempts of artificial triggering. Moreover we measured properly if critical infrastructure (in our case a ski run) was reached by the avalanches or not. The spatial distributed sensing approach allowed us to relate the amplitude and spectral content of the signals to avalanche size, avalanche speed and snow properties of the avalanches. In conclusion we summarize that distributed acoustic fiber optic sensing is a precise method to monitor avalanche activity, runout distances and avalanche properties.

  15. Demodulation technique based on diffraction optical elements for fiber Bragg grating sensing system

    Science.gov (United States)

    Feng, Zhongwei; Zhang, Li

    2010-11-01

    A new demodulation technique based on diffraction grating is proposed for high speed application. Compared with tunable filter method, the diffraction grating method has the advantages of potential high interrogation speed, high energy efficiency, no sweeping movements, which makes it a competitive interrogation method in certain field such as dynamic strain monitoring. The optical layout is crucial to guarantee the required performance of the interrogator. A structure which consists of two diffraction gratings, a fiber collimator, a reflection mirror, and a detector is adopted in the consideration of spectrum resolution, optical aberration, and geometrical size. The initial parameters for the structure are figured out by the optical path calculation involving the coefficient of the employed optical elements. The optimized procedure is following sequentially in order to minimize the aberration and obtain the pre-defined specifications theoretically. As the central wavelength for the interrogator is 1550nm, the InGaAs linear array sensor is introduced as the photoelectrical detector. Experiment of demodulation for FBG sensing system is carried out to verify the feasibility of this technique. The wavelength resolution for the interrogator is 1pm, and the demodulation speed is about 2kHz.

  16. 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)

  17. Optical fiber core diameter mismatched in-fiber Mach-Zehnder interferometer for strain sensing

    Science.gov (United States)

    Zhao, Na; Fu, Haiwei; Qiao, Xueguang; Shao, Min; Li, Huidong; Liu, Qinpeng; Gao, Hong; Yan, Xu; Zhang, Yunshan

    2015-02-01

    A novel strain sensor based on in-fiber Mach-Zehnder interferometer (MZI) is proposed in this paper. The sensor is with the structure of single mode-thin core-multimode-thin core-single mode (STMTS) fiber structures fabricated by splicing two short sections of thin core fiber (TCF) among lead-in single mode fiber (SMF), multi-mode fiber (MMF) and lead-out SMF. The first section of TCF excites the core mode and high-order modes in the core of MMF and the second section of TCF couples the core mode and high-order modes into lead-out SMF to procedure inter-modes interferences. The sensor with MMF length of 20mm and TCFs length of 1mm is fabricated. The transmission spectrum of the sensor with respect to external strain has been studied by experiment. The result shows that the central wavelength respects to external strain with a good linearity. The strain sensitivity of the sensor is -2 pm/ue; over a strain range of 0 to 4500ue;. The temperature response of the sensor is also studied by experiment. The results indicate that the central wavelength of the transmission spectrum is insensitive to external temperature change. The proposed sensor features the advantages of easy fabrication, low cost and high sensitivity, and it exhibits great potential in single parameter measurement.

  18. 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.

  19. Sub-centimetre Spatial Resolution in Distributed Fibre Sensing, based on Dynamic Brillouin Grating in Optical Fibers

    OpenAIRE

    Chin, S.; Primerov, N.; The?venaz, Luc

    2012-01-01

    Optical fibre sensors based on stimulated Brillouin scattering in optical fibers have now clearly demonstrated their excellent capability for long-range distributed strain and temperature measurements. The fibre is used as sensing element and a value for temperature and/or strain can be obtained from any point along the fibre. While the spatial resolution of classical configurations is practically limited to 1 meter by the phonon lifetime, novel approaches have been demonstrated these past ye...

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

    OpenAIRE

    Hiroshi Tsuda

    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...

  1. 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.

  2. 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.

  3. A Multi-D-Shaped Optical Fiber for Refractive Index Sensing

    OpenAIRE

    Chien-Hsing Chen; Tzu-Chein Tsao; Jaw-Luen Tang; Wei-Te Wu

    2010-01-01

    A novel class of multi-D-shaped optical fiber suited for refractive index measurements is presented. The multi-D-shaped optical fiber was constructed by forming several D-sections in a multimode optical fiber at localized regions with femtosecond laser pulses. The total number of D-shaped zones fabricated could range from three to seven. Each D-shaped zone covered a sensor volume of 100 ?m depth, 250 ?m width, and 1 mm length. The mean roughness of the core surface obtained by the AFM image...

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

    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,...

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

    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...

  6. Optical fiber sensing of strain in synthetic fiber tension members: recent results

    OpenAIRE

    Uttamchandani, Deepak G.; Sass, A.; Culshaw, Brian; Overington, M. S.; Parsey, M.; Facchini, Massimo; Thévenaz, Luc

    1999-01-01

    Strain measurements on synthetic fibre rope constructions ofthe type used in marine applications are reported. The ropes are of a novel construction by virtue of incorporation of fibre-optic sensors for strain measurement. Two instrumentation approaches -a Brillouin strain measuring system and a RF sub-carrier strain measuring system -have been utilised to interrogate the fibre sensors.

  7. Efficient modeling of optical waveguides and fibers with chemical sensing applications

    Science.gov (United States)

    Weisshaar, Andreas; Remley, Kate A.

    1996-08-01

    The impedance boundary method of moments (IBMOM) for planar optical waveguides is reviewed. An extension of the IBMOM for optical fibers with truncated graded index profile is described. Results for a step index fiber show that virtually exact solutions for the modal field profile and propagation constant can be obtained with only three Legendre expansion functions. The IBMOM is applied in the design and analysis of an evanescent field optical waveguide chemical sensor which utilizes an antiresonant reflecting optical waveguide (ARROW) structure and is implemented as a Mach-Zehnder interferometer. The ARROW structure allows the use of a 5 micrometer wide guiding region for efficient coupling into a single mode optical fiber. The ARROW sensor is designed for a sensitivity of 180 degrees/cm phase change for a change of 0.05 in refractive index.

  8. Thymol blue immobilized on tapered fibers as optical transducer for pH sensing

    Science.gov (United States)

    Baldini, Francesco; Ciaccheri, Leonardo; Falai, Alida; Mignani, Anna G.; Rayss, Jan; Sudolski, Grzegorz

    1999-02-01

    The present work is concerned with the optical characterization of an evanescent wave sensor for pH detection. First, the interaction between the solution containing the acid-base indicator and the fiber core was investigated. Then, the acid-base indicator, thymol blue, was covalently immobilized on the core of a 200/380 micrometers fiber by means of a silylation process of the glass surface. The fiber core surface was modified along a section of 8 mm. A comparison was made using both bare and tapered fibers, with a tapering ratio (fiber diameter/waist diameter) of 2.3. An enhancement in sensitivity of a factor 6 was observed with tapered fibers in the 1/2.5 range, and a sensitivity of 0.05 pH units was attained.

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

    OpenAIRE

    Zhao, Mingtao; Huang, Yong; 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...

  10. 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

  11. 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

  12. Acousto-opto-mechanical theory for polarization maintaining optical fibers in Brillouin based sensing

    Science.gov (United States)

    Wang, Xiaoling; Ansari, Farhad; Meng, Dewei; Bao, Tengfei

    2015-01-01

    Change in phase or wavelength for interferometric and fiber Bragg Gratings (FBG) based sensors can be described by strain-optic effects. In Brillouin sensors, strain sensitivity need to be expressed in terms of acousto-opto-mechanical properties of fibers. It is then possible to formulate theoretical relationships that lead to the evaluation of strain sensitivities and establishment of gauge factors for Brillouin based sensors. This article reports on the derivation of generalized relationships describing the strain sensitivity in terms of acousto-optic effects in optical fibers. In particular, the formulations correspond to polarization maintaining fibers at various polarization angles with respect to the slow axis of the fiber. The scope of research encompassed theoretical and experimental studies involving both single mode as well as polarization maintaining optical fibers subjected to strain under isothermal conditions. A high resolution BOTDA was employed in the experiments in order to verify the validity of theoretical relationships between strain and Brillouin frequency shifts for different polarization angles.

  13. 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.

  14. High-spatial-resolution distributed optical fiber strain or temperature sensing

    Science.gov (United States)

    Julian, Princy L.; Farhadiroushan, Mahmoud; Handerek, Vincent A.; Rogers, Alan J.

    1999-02-01

    Two high resolution optical-fiber system for the distributed measurement of strain or temperature have been investigated. The first is a fully distributed system, based on a high spatial resolution POTDR which benefits from photon-counting detection, with a spatial resolution of 50mm. The second is a novel quasi-distributed system which uses coherent coupling of backscattered light in a high birefringence fiber, and also uses photon counting detection.

  15. 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.

  16. 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 optic s sensors * Backscattering * Nanomaterials Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.179, year: 2013

  17. Investigating Into Sensing Properties of Fiber Optic Thermo-Hygrometers for CMS

    CERN Document Server

    Wallangen, Veronica

    2013-01-01

    A set of optical fiber sensors based on FBG-technology are to be installed in the CMS experiment for the first time. These sensors consists of coupled pairs of temperature and relative humidity sensors and this report outlines the calibration performed primarily on the temperature sensors in preparation of the installation.

  18. 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.

  19. 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.

  20. High-Tg TOPAS microstructured polymer optical fiber for fiber Bragg grating strain sensing at 110 degrees

    DEFF Research Database (Denmark)

    Markos, Christos; Stefani, Alessio

    2013-01-01

    We present the fabrication and characterization of fiber Bragg gratings (FBGs) in an endlessly single-mode microstructured polymer optical fiber (mPOF) made of humidity-insensitive high-Tg TOPAS cyclic olefin copolymer. The mPOF is the first made from grade 5013 TOPAS with a glass transition temperature of Tg = 135°C and we experimentally demonstrate high strain operation (2.5%) of the FBG at 98°C and stable operation up to a record high temperature of 110°C. The Bragg wavelengths of the FBGs are around 860 nm, where the propagation loss is 5.1dB/m, close to the fiber loss minimum of 3.67dB/m at 787nm.

  1. 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.

  2. Coaxial fiber-optic chemical-sensing excitation-emission matrix fluorometer.

    Science.gov (United States)

    Kim, Yoon-Chang; Jordan, James A; Chávez, Diana; Booksh, Karl S

    2011-02-01

    Great reductions in the overall size and complexity of high throughput multichannel UV-visible fluorometers were achieved by coupling a compact optical fiber array to compact dispersive transmission optics. The coaxial configuration centers on the insertion of a silica/silica optical fiber into the hollow region of a UV-fused silica capillary waveguide. The outer core delivers the maximum power of the narrow wavelength region of the excitation spectrum created by coupling a xenon arc discharge lamp to a compact spectrometer. The molecular fluorescence resulting from the interaction of light emitted at the distal end of the hollow waveguide and the sample matrix is received and transmitted to a CCD via a compact dispersive grating-prism (grism) optical assembly. A linear array of the coaxial optical fibers permits a full excitation-emission matrix spectrum of the analyte matrix to be projected onto the face of the CCD. The in situ identification and monitoring of polycyclic aromatic hydrocarbons was carried out for the initial application testing for this prototype. PMID:21283188

  3. Fiber-optic sensing in cryogenic environments. [for rocket propellant tank monitoring

    Science.gov (United States)

    Sharma, M.; Brooks, R. E.

    1980-01-01

    Passive optical sensors using fiber-optic signal transmission to a remote monitoring station are explored as an alternative to electrical sensors used to monitor the status of explosive propellants. The designs of passive optical sensors measuring liquid level, pressure, and temperature in cryogenic propellant tanks are discussed. Test results for an experimental system incorporating these sensors and operating in liquid nitrogen demonstrate the feasibility of passive sensor techniques and indicate that they can serve as non-hazardous replacements for more conventional measuring equipment in explosive environments.

  4. 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"

  5. 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.

  6. 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)

  7. Preparation of Tapered Optical Fibers to utilize the Evanescent Field for Sensing Applications

    OpenAIRE

    Karra. Sony*, Soumya. M

    2013-01-01

    Optical fibers can be tapered in order to utilize the evanescent field present in the cladding region of the fiber. At the beginning of the taper region most of the power is present in the core. In the down taper region the light in the core region couples to the cladding region where the evanescent field is present. In the up taper region, light in the cladding region again couples back into the core region. Our experiment discusses about the process of tapering and the principle of tapered ...

  8. High-Performance Raman-Based Distributed Fiber-Optic Sensing Under a Loop Scheme Using Anti-Stokes Light Only

    OpenAIRE

    Soto, Marcelo A.; Signorini, Alessandro; Nannipieri, Tiziano; Faralli, Stefano; Bolognini, Gabriele

    2011-01-01

    A distributed fiber-optic temperature sensor technique inherently allowing for system calibration, compensating time-dependent variations of the fiber losses as well as local external perturbations, is proposed using a loop-scheme together with Raman anti-Stokes-only measurement. A temperature resolution enhancement with respect to a standard loop configuration is shown by experiments, providing a robust and reliable high-performance sensing technique for long sensing ranges.

  9. 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)

  10. 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.

  11. 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

  12. 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...

  13. 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.

  14. 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.

  15. Review on Optical Fiber Sensing Technologies for Industrical Applications at the NEL-FOST

    OpenAIRE

    Yang, Minghong; Li, Sheng; Jiang, Desheng

    2014-01-01

    The research on engineering experiment is a key step in translating technical development to industrial application. According to our practical experience for more than 30 years and some applications of the fire alarm system, bridge, coal and power safety ensuring system, this paper reviews on engineering technique problems in the application of fiber optic sensor and their solutions, which may provide some references for wider industrial applications.

  16. 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 arraa 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.

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

    Directory of Open Access Journals (Sweden)

    Chuji Wang

    2013-06-01

    Full Text Available 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 laboratory and their capabilities of detecting the respective quantities were demonstrated. Later, all of the sensors were installed in a test grout cube for real-time monitoring. This work presents the results obtained in the laboratory-based experiments as well as the results from the real-time monitoring process in the test cube.

  18. Sensing parts per million levels of gaseous NO2 by a optical fiber transducer based on calix[4]arenes.

    Science.gov (United States)

    Ohira, Shin-Ichi; Wanigasekara, Eranda; Rudkevich, Dmitry M; Dasgupta, Purnendu K

    2009-03-15

    Calixarenes are interesting building blocks in supramolecular receptor design. They can be easily functionalized to give the desired guest binding and sequestration properties. We demonstrate here the use of simple alkylated calixarenes as novel NO(2) sensors. Upon reacting with gaseous NO(2), alkylated calixarenes form stable calixarene-NO(+) (nitrosonium) complexes that have a deep purple color. This specific and selective formation of the colored complex was used to develop a fiber optic based colorimetric NO(2) sensor. Several alkylated calixarenes are used and tested as sensing materials. The calixarene compound was immobilized on a fine mesh silica-gel coated thin layer chromatography plate. The sensing plate was coupled with a fiber optic based photodetector. Gas samples were sampled in a manner where they impinged on the surface of sensing plate. The light transmission through the plate was continuously monitored. For a 5 min sample, the limit of detection was 0.54 ppmv with 1,3-alternate O-hexyl calix[4]arene (1a). There were no significant response differences between different conformations of calixarenes such as 1,3-alternate or cone. This chemistry can form the basis of a colorimetric sensor that relies on extant filter tape technology. With calixarenes however, such a reaction is potentially reversible - color formed upon reaction with NO(2) can be reversed by flushing the sensing plate by purified air. While we found that the removal of the developed color can be accelerated by simultaneous heating and suction, permitting the reuse of the same sensing area multiple times, we also observed that the sensitivity gradually decreased. The nitrosonium calixarene derivative tends to transform to the nitrated form; this process is catalyzed by light. Several methylated calixarenes were synthesized and tested but a fully satisfactory solution has proven elusive. PMID:19159804

  19. 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.

  20. 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.

  1. 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)

  2. 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.

  3. 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.

  4. Fiber-optic gas pressure sensing with a laser-heated silicon-based Fabry-Perot interferometer.

    Science.gov (United States)

    Liu, Guigen; Han, Ming

    2015-06-01

    We report a novel fiber-optic sensor for measurement of static gas pressure based on the natural convection of a heated silicon pillar attached to a fiber tip functioning as a Fabry-Perot interferometer (FPI). A visible laser beam is guided by the fiber to efficiently heat the silicon pillar, while an infrared whitelight source, also guided by the fiber, is used to measure the temperature of the FPI, which is influenced both by the laser power and the pressure through natural convection. We theoretically and experimentally show that, by monitoring the fringe shift caused by the laser heating, air pressure sensing with little temperature cross-sensitivity can be achieved. The pressure sensitivity can be easily tuned by adjusting the heating laser power. In our experiment, the sensor performance within the temperature range from 20°C to 50°C and the pressure range from 0 to 1400 psi has been characterized, showing an average sensitivity of -0.52??pm/psi. Compared to the passive version of the sensor, the pressure sensitivity was ?15 times larger, and the temperature cross-sensitivity was ?100 times smaller. PMID:26030532

  5. Optimization of wideband fiber optic hydrophone probe for ultrasound sensing applications

    Science.gov (United States)

    Minasamudram, Rupa Gopinath

    Acoustic characterization of medical ultrasound devices is needed for optimization of image quality in diagnostic applications and to ensure their safety and effectiveness in therapeutic applications. New generation of acoustic transducers operating at fundamental frequency 15 MHz are being developed and FDA requires that as many as 8 harmonics are considered for real-time pressure-time waveform measurements in dispersive nonlinear medium. Therefore, hydrophone probes are required to perform characterization of the acoustic output of these devices at least up to 100 MHz in terms of frequency response. The primary goal of this thesis is to develop a Fiber Optic Hydrophone Probe (FOHP) for spatial averaging free characterization of ultrasound field till 100 MHz. Spatial averaging free design of the sensor is based on optimization of fiber geometry to achieve an active fiber dimension of the order of 7 mum to be comparable with half of the acoustic wavelength at 100 MHz. An innovative aspect of this work includes the development of a semi-empirical model for extraction of complex refractive index at optical wavelengths of 980 nm, 1480 nm and 1550 nm and stress-strain relationship of thin film gold for thickness ranging from 2nm--35nm. These are indispensable in modeling and optimization of 100 MHz FOHP in calculation of optimized pressure to voltage responsivity. For responsivity optimization, a novel multi-physics numerical model based on the Finite Element Method (FEM) was employed to solve electromagnetic, mechanics, and acoustics performance of the FOHP. The model and the selection of its input parameters, including coupled acousto-optic interaction of thin film gold, are based on published physical parameters and accurate extraction of various fiber parameters. Optimization results indicate that cylindrically etched FOHP with 6 mum tip diameter and 5 nm gold coating provides the highest responsivity performance of 234 dB re 1V/ muPa. The experimental verification of the thin film coated FOHP using 1 MPa pressure amplitude, produced unprecedented voltage responsivity between -234 and -254 dB re 1V/muPa or 2V/MPa and 200 mV/MPa, respectively. The optimum detection sensitivity of around 0.3 kPa is achieved by Relative Intensity Noise cancellation of 10 dB using balanced optical photo-detector.

  6. Fiber optic strain, temperature and shape sensing via OFDR for ground, air and space applications

    Science.gov (United States)

    Bos, Joseph; Klein, Justin; Froggatt, Mark; Sanborn, Eric; Gifford, Dawn

    2013-09-01

    Optical Frequency Domain Reflectometry (OFDR) is used to interrogate fiber sensors adhered to various structures. Temperatures in excess of 1000°C are observed on a thermal-barrier coated stainless steel test plate as it is exposed to a high-temperature torch. The surface temperature distribution is mapped with 5 mm spatial resolution at 100 Hz, revealing large spatial and temporal thermal gradients at coating defect locations. Results and response times are compared with conventional K type thermocouples. Also presented in this work, are real-time position, shape and twist measurements of a simple structure as it is subjected to various loads.

  7. Process monitoring and control with fiber optics

    Science.gov (United States)

    Marcus, Michael A.

    1991-03-01

    The use of distributed and multiplexed fiber-optic sensors in the process monitoring and control environment is described. Recent application development work based on OTDR signal processing techniques is reviewed. Applications investigated include distributed temperature sensing strain sensing humidity sensing chemical sensing and distributed alarm sensing. Multiplexable fiber-optic sensing applications including edge sensing distance sensing vibration and particle sizing based on photon correlation spectroscopy are also described. The principles underlying these measurement techniques are presented and process application examples are provided.

  8. Fiber Singular Optics

    Directory of Open Access Journals (Sweden)

    A. V. Volyar

    2002-06-01

    Full Text Available 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.

  9. 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.

  10. A practical fiber optic accelerometer

    Science.gov (United States)

    Layton, M. R.; Danver, B. A.; Lastofka, J. D.; Bevan, D. P.; Carome, E. F.

    1988-03-01

    A fiber optic accelerometer exhibiting high sensitivity has been developed. The transduction element is configured optically as a Michelson interferometer. Mechanically it consists of a pair of liquid-filled mandrels wrapped with equal lengths of single mode fiber. Acceleration sensitivities in excess of 2000 radians/g are readily achieved. Such accelerometers have been employed as sensing elements in gradient hydrophones that have been tested successfully both in the laboratory and in the field. The practicality of this accelerometer's design and operation is compared with that of other recently proposed fiber optic interferometric vibration sensors.

  11. Photonic crystal sensing of components of a liquid mixture using an optical fiber spectrometer

    Science.gov (United States)

    Fudouzi, Hiroshi; Sawada, Tsutomu

    2007-09-01

    We report the application of a photonic crystal sensor for the components of a liquid mixture by a simple and easy technique. A closely packed colloidal crystal film is made of arrayed 202-nm PS particles and PDMS elastomer is used for filling the voids in the film. Bragg's diffraction in the visible wavelength region causes the formation of a structural color in the colloidal crystal. The structural color varies according to the solvents depending on the swelling ability of the PDMS elastomer. We can perform the quantitative analysis of the swelling phenomena by measuring Bragg's diffraction peaks. The peak shifts as a function of the mixing ratio of the solvents, i.e., methanol, ethanol, and propanol. The peak position is proportional to the solvent concentration. In the case of a water-ethanol system, there is little peak-shift up to 80 vol.% of ethanol concentration. Above this concentration, the rate of peak shift increases beyond 50 nm. A reflectance spectrometer enables the detection of the components of ethanol liquids with the volume concentration of water ranging from 0 to 10%. In this study, a commercially available optical fiber spectrometer detects the volume concentrations of water of the order of 1 vol.% in ethanol. The photonic sensor has the potential to be used in a rapid analysis method that employs a portable optical fiber spectrometer.

  12. 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)

  13. 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.

  14. Fiber optic sensors

    Science.gov (United States)

    Hesse, J.; Sohler, W.

    1984-01-01

    A survey of the developments in the field of fiber optics sensor technology is presented along with a discussion of the advantages of optical measuring instruments as compared with electronic sensors. The two primary types of fiber optics sensors, specifically those with multiwave fibers and those with monowave fibers, are described. Examples of each major sensor type are presented and discussed. Multiwave detectors include external and internal fiber optics sensors. Among the monowave detectors are Mach-Zender interferometers, Michelson interferometers, Sagnac interferometers (optical gyroscopes), waveguide resonators, and polarimeter sensors. Integrated optical sensors and their application in spectroscopy are briefly discussed.

  15. Omnidirectional fiber optic tiltmeter

    Science.gov (United States)

    Benjamin, B.C.; Miller, H.M.

    1983-06-30

    A tiltmeter is provided which is useful in detecting very small movements such as earth tides. The device comprises a single optical fiber, and an associated weight affixed thereto, suspended from a support to form a pendulum. A light source, e.g., a light emitting diode, mounted on the support transmits light through the optical fiber to a group of further optical fibers located adjacent to but spaced from the free end of the single optical fiber so that displacement of the single optical fiber with respect to the group will result in a change in the amount of light received by the individual optical fibers of the group. Photodetectors individually connectd to the fibers produce corresponding electrical outputs which are differentially compared and processed to produce a resultant continuous analog output representative of the amount and direction of displacement of the single optical fiber.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. An optical-fiber-scale electro-optic probe for minimally invasive high-frequency field sensing.

    Science.gov (United States)

    Lee, Dong-Joon; Whitaker, John F

    2008-12-22

    A sub-millimeter-dimension electro-optic probe that provides enhanced scanning accessibility with significantly less intrusiveness than metal-based or even other dielectric probes during electromagnetic characterization of microwave devices is presented. The quantitative and qualitative relative invasiveness of the probe on the operation of an example antenna device-under-test is explored with respect to previously demonstrated fiber and wafer electro-optic sensors. We also demonstrate that the miniaturized probe, with a diameter of 125 microm, can be used to reconstruct the three orthogonal vector components of near-electric fields without the need for different probe crystals or multiple calibration procedures. Finally, the advantages of the reduced size and invasiveness of the new micro-scale probe are demonstrated through the enhanced resolution of detailed images extracted from planar antennas, as well as the capability of reaching into circuit locations heretofore inaccessible. PMID:19104590

  2. Fiber optic plenum cable

    Science.gov (United States)

    Angeles, Purita; Kurt, Jeffrey

    1986-11-01

    Fiber optic plenum cables use fluorocarbon jackets to provide the low smoke and flame characteristics required to be classified as plenum cables. Compared with more commonly used optical cable jackets, fluorocarbon jackets have less creep resistance and potentially higher shrinkback. Consequently, the establishment of satisfactory plenum cables required both specialized modeling and experimental cable testing. This paper describes theoretical modelling of the change in attenuation of a plenum fiber optic cable as a function of temperature range. The temperature test results of one and two fiber plenum cables and single fiber connectorized assemblies show the models to be useful tools in rationally developing fiber optic plenum cable.

  3. 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.

  4. 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.

  5. Polymer optical fibers integrated directly into 3D orthogonal woven composites for sensing

    Science.gov (United States)

    Hamouda, Tamer; Seyam, Abdel-Fattah M.; Peters, Kara

    2015-02-01

    This study demonstrates that standard polymer optical fibers (POF) can be directly integrated into composites from 3D orthogonal woven preforms during the weaving process and then serve as in-situ sensors to detect damage due to bending or impact loads. Different composite samples with embedded POF were fabricated of 3D orthogonal woven composites with different parameters namely number of y-/x-layers and x-yarn density. The signal of POF was not affected significantly by the preform structure. During application of resin using VARTM technique, significant drop in backscattering level was observed due to pressure caused by vacuum on the embedded POF. Measurements of POF signal while in the final composites after resin cure indicated that the backscattering level almost returned to the original level of un-embedded POF. The POF responded to application of bending and impact loads to the composite with a reduction in the backscattering level. The backscattering level almost returned back to its original level after removing the bending load until damage was present in the composite. Similar behavior occurred due to impact events. As the POF itself is used as the sensor and can be integrated throughout the composite, large sections of future 3D woven composite structures could be monitored without the need for specialized sensors or complex instrumentation.

  6. 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.

  7. Remote optical fiber dosimetry

    International Nuclear Information System (INIS)

    Optical fibers offer a unique capability for remote monitoring of radiation in difficult-to-access and/or hazardous locations. Optical fiber sensors can be located in radiation hazardous areas and optically interrogated from a safe distance. A variety of remote optical fiber radiation dosimetry methods have been developed. All of the methods take advantage of some form of radiation-induced change in the optical properties of materials such as: radiation-induced darkening due to defect formation in glasses, luminescence from native defects or radiation-induced defects, or population of metastable charge trapping centers. Optical attenuation techniques are used to measure radiation-induced darkening in fibers. Luminescence techniques include the direct measurement of scintillation or optical excitation of radiation-induced luminescent defects. Optical fiber radiation dosimeters have also been constructed using charge trapping materials that exhibit thermoluminescence or optically stimulated luminescence (OSL)

  8. Fiber optic irradiation

    International Nuclear Information System (INIS)

    The transmission of information via optical fiber became more attractive due its advantageous characteristics in relation to the radio waves or metallic wires. Beside the applications in data-communication, the optic fibers have presented great benefit in the area of sensors and industrial controls, including the nuclear area. However, a major problem in the application of optical fibers in nuclear environments is the presence of ionizing radiation. When optical fibers are exposed to radiation field, color center are formed in the optical core or cladding and its can degrade the transmission. In this work it is presented the theoretical basis for color centers formation in optical fibers and the results attained in an exploratory experiment to measure the attenuation in a multimode optic fiber using a gamma ray source. (author)

  9. Rayleigh fiber optics gyroscope

    OpenAIRE

    Kung, A.; Budin, J.; The?venaz, 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

  10. Advanced fiber-optic acoustic sensors

    Science.gov (United States)

    Teixeira, João G. V.; Leite, Ivo T.; Silva, Susana; Frazão, Orlando

    2014-09-01

    Acoustic sensing is nowadays a very demanding field which plays an important role in modern society, with applications spanning from structural health monitoring to medical imaging. Fiber-optics can bring many advantages to this field, and fiber-optic acoustic sensors show already performance levels capable of competing with the standard sensors based on piezoelectric transducers. This review presents the recent advances in the field of fiber-optic dynamic strain sensing, particularly for acoustic detection. Three dominant technologies are identified — fiber Bragg gratings, interferometric Mach-Zehnder, and Fabry-Pérot configurations — and their recent developments are summarized.

  11. Random-access distributed fiber sensing

    OpenAIRE

    Zadok, Avinoam; Antman, Yair; Primerov, Nikolay; Denisov, Andrey; Sancho, Juan; The?venaz, Luc

    2012-01-01

    Optical sensing offers an attractive solution to the societal concern for prevention of natural and human-generated threats and for efficient use of natural resources. The unprecedented properties of optical fibers make them ideal for implementing a ‘nervous system’ in structural health monitoring: they are small, low-cost and electrically and chemically inert. In particular, the nonlinear interaction of stimulated Brillouin scattering allows for the distributed measurement of strain and ...

  12. Fiber optics in SHIVA

    International Nuclear Information System (INIS)

    SHIVA is a twenty arm laser which is controlled with a network of fifty computers, interconnected with digital fiber optic links. Three different fiber optic systems employed on the Shiva laser will be described. Two of the systems are for digital communications, one at 9600 baud and the other at 1 megabaud. The third system uses fiber optics to distribute diagnostic triggers with subnanosecond jitter

  13. 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

  14. 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

    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 propagating nanosecond pulses through the silica-core of the fiber. To the best of our knowledge, this is also the first experiment where a liquid is filled into the holes of a solid-core microstructured fiber to control the phase-match conditions for FWM. (C) 2011 Optical Society of America

  15. Multimode optical fiber

    Science.gov (United States)

    Bigot-Astruc, Marianne; Molin, Denis; Sillard, Pierre

    2014-11-04

    A depressed graded-index multimode optical fiber includes a central core, an inner depressed cladding, a depressed trench, an outer depressed cladding, and an outer cladding. The central core has an alpha-index profile. The depressed claddings limit the impact of leaky modes on optical-fiber performance characteristics (e.g., bandwidth, core size, and/or numerical aperture).

  16. Fiber Optics Basics

    Science.gov (United States)

    This pdf from OP-TEC, the National Center for Optics and Photonics Education, addresses basic concepts underlying the operation of fiber lasers. This free 26 page document supplements the fiber laser material presented in an Elements of Photonics Course by provided a more current and detailed description of how lasers operate. This course covers basic laser operations, basic structure of fiber lasers, pulsing methods, output characteristics of fiber lasers, and advanced structures.

  17. 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.

  18. Fiber optic hydrophone

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmenko, P.J.; Davis, D.T.

    1994-05-10

    A miniature fiber optic hydrophone based on the principles of a Fabry-Perot interferometer is disclosed. 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 optical 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. 2 figures.

  19. An approach to continuous on-site monitoring of contact forces in current collectors by a fiber optic sensing system

    Science.gov (United States)

    Schröder, Kerstin; Ecke, Wolfgang; Kautz, Michael; Willett, Simon; Jenzer, Matthias; Bosselmann, Thomas

    2013-02-01

    In the EU railway network, a multitude of railway companies runs their rolling stock on tracks which are not in their own responsibility. Consequently, permanent monitoring of security-relevant parameters becomes an issue of increasing importance. In order to characterize the status of the catenary-current collector interface, compliance with the specified contact force between them is a generally agreed-upon quality parameter. We report here on an approach to monitor contact forces (without correction of dynamic parts in this first step) inline using a potentially low-cost fiber optic sensing system which is insensitive to the high electrical potential and to field changes. It was implemented and tested successfully on regular trains by replacing the current collector with a sensor-embedded one, and by adding a small-sized signal processing unit in the driver cabin. In this article, we describe the construction and application results of the system and discuss its advantages and limitations. Sensor characteristics are investigated with the help of a mechanical model. The system has shown its potential during test drives on railway tracks in Switzerland.

  20. Phase noise in fiber-optic parametric amplifiers and converters and its impact on sensing and communication systems.

    Science.gov (United States)

    Moro, Slaven; Peric, Ana; Alic, Nikola; Stossel, Bryan; Radic, Stojan

    2010-09-27

    We present a theoretical analysis describing the spectral dependence of phase noise in one-pump fiber parametric amplifiers and converters. The analytical theory is experimentally validated and found to have high predictive accuracy. The implications related to phase-coded sensing and communications systems are discussed. PMID:20941041

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

    OpenAIRE

    Atie, Elie M.; Xie, Zhihua; 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...

  2. Fiber optics for controls

    Science.gov (United States)

    Seng, Gary T.

    1987-01-01

    The challenge of those involved in control-system hardware development is to accommodate an ever-increasing complexity in aircraft control, while limiting the size and weight of the components and improving system reliability. A technology that displays promise towards this end is the area of fiber optics for controls. The primary advantages of employing optical fibers, passive optical sensors, and optically controlled actuators are weight and volume reduction, immunity from electromagnetic effects, superior bandwidth capabilities, and freedom from short circuits and sparking contacts. Since 1975, NASA Lewis has performed in-house, contract, and grant research in fiber optic sensors, high-temperature electro-optic switches, and fly-by-light control-system architecture. Passive optical sensor development is an essential yet challenging area of work and has therefore received much attention during this period. A major effort to develop fly-by-light control-system technology, known as the Fiber-Optic Control System Integration (FOCSI) program, was initiated in 1985 as a cooperative effort between NASA and DOD. Phase 1 of FOCSI, completed in 1986, was aimed at the design of a fiber-optic integrated propulsion/flight control system. Phase 2, yet to be initiated, will provide subcomponent and system development, and a system engine test. In addition to a summary of the benefits of fiber optics, the FOCSI program, sensor advances, and future directions in the NASA Lewis program will be discussed.

  3. 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

  4. Remote open-path cavity-ringdown spectroscopic sensing of trace gases in air, based on distributed passive sensors linked by km-long optical fibers.

    Science.gov (United States)

    He, Yabai; Jin, Chunjiang; Kan, Ruifeng; Liu, Jianguo; Liu, Wenqing; Hill, Julian; Jamie, Ian M; Orr, Brian J

    2014-06-01

    A continuous-wave, rapidly swept cavity-ringdown spectroscopic technique has been developed for localized atmospheric sensing of trace gases at remote sites. It uses one or more passive open-path optical sensor units, coupled by optical fiber over distances of >1 km to a single transmitter/receiver console incorporating a photodetector and a swept-frequency diode laser tuned to molecule-specific near-infrared wavelengths. Ways to avoid interference from stimulated Brillouin scattering in long optical fibers have been devised. This rugged open-path system, deployable in agricultural, industrial, and natural atmospheric environments, is used to monitor ammonia in air. A noise-limited minimum detectable mixing ratio of ~11 ppbv is attained for ammonia in nitrogen at atmospheric pressure. PMID:24921513

  5. 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...

  6. Fiber Optic Cables

    Science.gov (United States)

    Bartelt, Terry L. M.

    This brief interactive activity, by the Electromechanical Digital Library and Wisconsin Technical College System faculty, is an easy-to-use introduction to fiber optic cables and their uses. Students are able to reveal each section at their leisure as they click through the helpful illustrations and animations on fiber optic cable components, LEDâ??s, multi-mode and single-mode cables, and cable connectors. Three review questions wrap up the slide show to test knowledge gained. This would be a great resource for teachers to help introduce the topic to students, or for students to have a comprehensive overview of fiber optic cables.

  7. 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.

  8. Comparison of evanscent-wave and leaky-wave fiber optic sensing structures for gas detection.

    Czech Academy of Sciences Publication Activity Database

    Mrázek, Jan; Mat?jec, Vlastimil; Chomát, Miroslav; Renault, N. J.; Dzyadevych, S.; Rose, K.

    [Monastir] : [Faculté des Sciences de Monastir], 2004. s. 121. [Journees Maghreb-Europe sur les Materiaux et Leurs Applications aux Dispositifs et Capteurs MADICA 2004 /4./. 29.11.2004-01.12.2004, Tunis] Institutional research plan: CEZ:AV0Z2067918 Keywords : fibre optic sensors * gas sensors Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  9. Chemical Sensing Using Fiber Cavity Ring-Down Spectroscopy

    OpenAIRE

    Hans-Peter Loock; Barnes, Jack A.; Cheung, Adrienne H.; 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 ...

  10. 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

  11. Polymer optical fiber fuse

    CERN Document Server

    Mizuno, Yosuke; Tanaka, Hiroki; Nakamura, Kentaro

    2013-01-01

    Although high-transmission-capacity optical fibers are in demand, the problem of the fiber fuse phenomenon needs to be resolved to prevent the destruction of fibers. As polymer optical fibers become more prevalent, clarifying their fuse properties has become important. Here, we experimentally demonstrate a fuse propagation velocity of 21.9 mm/s, which is 1 to 2 orders of magnitude slower than that in standard silica fibers. The achieved threshold power density and proportionality constant between the propagation velocity and the power density are respectively 1/186 of and 16.8 times the values for silica fibers. An oscillatory continuous curve instead of periodic voids is formed after the passage of the fuse. An easy fuse termination method is presented herein, along with its potential plasma applications.

  12. Recent Development in Optical Fiber Biosensors

    Directory of Open Access Journals (Sweden)

    Catalina Bosch Ojeda

    2007-06-01

    Full Text Available Remarkable developments can be seen in the field of optical fibre biosensors in the last decade. More sensors for specific analytes have been reported, novel sensing chemistries or transduction principles have been introduced, and applications in various analytical fields have been realised. This review consists of papers mainly reported in the last decade and presents about applications of optical fiber biosensors. Discussions on the trends in optical fiber biosensor applications in real samples are enumerated.

  13. Fiber Optics: No Illusion.

    Science.gov (United States)

    American School and University, 1983

    1983-01-01

    A campus computer center at Hofstra University (New York) that holds 70 terminals for student use was first a gymnasium, then a language laboratory. Strands of fiber optics are used for the necessary wiring. (MLF)

  14. Fiber optic hydrogen sensor

    Science.gov (United States)

    Buchanan, B.R.; Prather, W.S.

    1991-01-01

    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.

  15. 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.

  16. Microstructured fibers for sensing applications

    Science.gov (United States)

    Petrovich, M. N.; van Brakel, A.; Poletti, F.; Mukasa, K.; Austin, E.; Finazzi, V.; Petropoulos, P.; O'Driscoll, E.; Watson, M.; DelMonte, T.; Monro, T. M.; Dakin, J. P.; Richardson, D. J.

    2005-11-01

    Microstructured fibers (MOFs) are among the most innovative developments in optical fiber technology in recent years. These fibers contain arrays of tiny air holes that run along their length and define the waveguiding properties. Optical confinement and guidance in MOFs can be obtained either through modified total internal reflection, or photonic bandgap effects; correspondingly, they are classified into index-guiding Holey Fibers (HFs) and Photonic Bandgap Fibers (PBGFs). MOFs offer great flexibility in terms of fiber design and, by virtue of the large refractive index contrast between glass/air and the possibility to make wavelength-scale features, offer a range of unique properties. In this paper we review the current status of air/silica MOF design and fabrication and discuss the attractions of this technology within the field of sensors, including prospects for further development. We focus on two primary areas, which we believe to be of particular significance. Firstly, we discuss the use of fibers offering large evanescent fields, or, alternatively, guidance in an air core, to provide long interaction lengths for detection of trace chemicals in gas or liquid samples; an improved fibre design is presented and prospects for practical implementation in sensor systems are also analysed. Secondly, we discuss the application of photonic bandgap fibre technology for obtaining fibres operating beyond silica's transparency window, and in particular in the 3?m wavelength region.

  17. Electrospun amplified fiber optics

    OpenAIRE

    Morello, Giovanni; Camposeo, Andrea; Moffa, Maria; Pisignano, Dario

    2015-01-01

    A lot of research is focused on all-optical signal processing, aiming to obtain effective alternatives to existing data transmission platforms. Amplification of light in fiber optics, such as in Erbium-doped fiber amplifiers, is especially important for an efficient signal transmission. However, the complex fabrication methods, involving high-temperature processes performed in highly pure environment, slow down the fabrication and make amplified components expensive with res...

  18. 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

  19. Optical detection of toluene in water by using an IGI optical fiber with a short sensing region.

    Czech Academy of Sciences Publication Activity Database

    Chomát, Miroslav; Berková, Daniela; Mat?jec, Vlastimil; Kašík, Ivan; Kuncová, Gabriela; Hayer, Miloš

    B87, ?. 2 (2002), s. 258-267. ISSN 0925-4005 R&D Projects: GA ?R GA102/99/0548 Institutional research plan: CEZ:AV0Z2067918 Keywords : optical fibres * fibre optic sensors * chemical sensors Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 1.893, year: 2002

  20. 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%.

  1. Polymer optical fiber tapering without the use of external heat source and its application to refractive index sensing

    Science.gov (United States)

    Ujihara, Hiroki; Hayashi, Neisei; Minakawa, Kazunari; Tabaru, Marie; Mizuno, Yosuke; Nakamura, Kentaro

    2015-07-01

    We perform a pilot trial of the highly convenient taper fabrication of perfluorinated graded-index polymer optical fibers. Instead of conventional external heating, we utilize internal heating caused by high-power propagating light (500 mW in this experiment). An approximately 4-mm-long section of a polymer fiber is tapered, and the outer diameter of the ?2-mm-long waist around its midpoint is approximately 200 µm, which is quite uniform with a standard deviation of 4.3 µm. The polymer fiber taper fabricated by this technique is shown to be capable of generating evanescent waves and thus measuring the refractive indices of liquids from 1.333 to 1.410.

  2. Mustiscaling Analysis applied to field Water Content through Distributed Fiber Optic Temperature sensing measurements

    Science.gov (United States)

    Benitez Buelga, Javier; Rodriguez-Sinobas, Leonor; Sanchez, Raul; Gil, Maria; Tarquis, Ana M.

    2014-05-01

    Soils can be seen as the result of spatial variation operating over several scales. This observation points to 'variability' as a key soil attribute that should be studied. Soil variability has often been considered to be composed of 'functional' (explained) variations plus random fluctuations or noise. However, the distinction between these two components is scale dependent because increasing the scale of observation almost always reveals structure in the noise. Geostatistical methods and, more recently, multifractal/wavelet techniques have been used to characterize scaling and heterogeneity of soil properties among others coming from complexity science. Multifractal formalism, first proposed by Mandelbrot (1982), is suitable for variables with self-similar distribution on a spatial domain (Kravchenko et al., 2002). Multifractal analysis can provide insight into spatial variability of crop or soil parameters (Vereecken et al., 2007). This technique has been used to characterize the scaling property of a variable measured along a transect as a mass distribution of a statistical measure on a spatial domain of the studied field (Zeleke and Si, 2004). To do this, it divides the transect into a number of self-similar segments. It identifies the differences among the subsets by using a wide range of statistical moments. Wavelets were developed in the 1980s for signal processing, and later introduced to soil science by Lark and Webster (1999). The wavelet transform decomposes a series; whether this be a time series (Whitcher, 1998; Percival and Walden, 2000), or as in our case a series of measurements made along a transect; into components (wavelet coefficients) which describe local variation in the series at different scale (or frequency) intervals, giving up only some resolution in space (Lark et al., 2003, 2004). Wavelet coefficients can be used to estimate scale specific components of variation and correlation. This allows us to see which scales contribute most to signal variation, or to see at which scales signals are most correlated. This can give us an insight into the dominant processes An alternative to both of the above methods has been described recently. Relative entropy and increments in relative entropy has been applied in soil images (Bird et al., 2006) and in soil transect data (Tarquis et al., 2008) to study scale effects localized in scale and provide the information that is complementary to the information about scale dependencies found across a range of scales. We will use them in this work to describe the spatial scaling properties of a set of field water content data measured in an extension of a corn field, in a plot of 500 m2 and an spatial resolution of 25 cm. These measurements are based on an optics cable (BruggSteal) buried on a ziz-zag deployment at 30cm depth. References Bird, N., M.C. Díaz, A. Saa, and A.M. Tarquis. 2006. A review of fractal and multifractal analysis of soil pore-scale images. J. Hydrol. 322:211-219. Kravchenko, A.N., R. Omonode, G.A. Bollero, and D.G. Bullock. 2002. Quantitative mapping of soil drainage classes using topographical data and soil electrical conductivity. Soil Sci. Soc. Am. J. 66:235-243. Lark, R.M., A.E. Milne, T.M. Addiscott, K.W.T. Goulding, C.P. Webster, and S. O'Flaherty. 2004. Scale- and location-dependent correlation of nitrous oxide emissions with soil properties: An analysis using wavelets. Eur. J. Soil Sci. 55:611-627. Lark, R.M., S.R. Kaffka, and D.L. Corwin. 2003. Multiresolution analysis of data on electrical conductivity of soil using wavelets. J. Hydrol. 272:276-290. Lark, R. M. and Webster, R. 1999. Analysis and elucidation of soil variation using wavelets. European J. of Soil Science, 50(2): 185-206. Mandelbrot, B.B. 1982. The fractal geometry of nature. W.H. Freeman, New York. Percival, D.B., and A.T. Walden. 2000. Wavelet methods for time series analysis. Cambridge Univ. Press, Cambridge, UK. Tarquis, A.M., N.R. Bird, A.P. Whitmore, M.C. Cartagena, and Y. Pachepsky. 2008. Multiscale analysis of soil transect data. Vadose Zone J. 7: 563-569. Vere

  3. Electrospun amplified fiber optics.

    Science.gov (United States)

    Morello, Giovanni; Camposeo, Andrea; Moffa, Maria; Pisignano, Dario

    2015-03-11

    All-optical signal processing is the focus of much research aiming to obtain effective alternatives to existing data transmission platforms. Amplification of light in fiber optics, such as in Erbium-doped fiber amplifiers, is especially important for efficient signal transmission. However, the complex fabrication methods involving high-temperature processes performed in a highly pure environment slow the fabrication process and make amplified components expensive with respect to an ideal, high-throughput, room temperature production. Here, we report on near-infrared polymer fiber amplifiers working over a band of ?20 nm. The fibers are cheap, spun with a process entirely carried out at room temperature, and shown to have amplified spontaneous emission with good gain coefficients and low levels of optical losses (a few cm(-1)). The amplification process is favored by high fiber quality and low self-absorption. The found performance metrics appear to be suitable for short-distance operations, and the large variety of commercially available doping dyes might allow for effective multiwavelength operations by electrospun amplified fiber optics. PMID:25710188

  4. Optical-fiber penetration devices

    International Nuclear Information System (INIS)

    Optical communications use optical-fiber signal-transmission lines and optical-fiber penetration instead of conventional wire penetration. Optical-fiber penetration devices must be gastight and have low transmission losses, characteristics which must be guaranteed irrespective of ambient conditions. Mitsubishi Electric has developed two methods of optical-fiber penetration, which are introduced in the article: hermetically sealed and organic material sealed. Both provide excellent resistance to environmental factors, including heat, radiation, and seismic distrubance. (author)

  5. 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.

  6. River Temperature Dynamics and Habitat Characteristics as Predictors of Salmonid Abundance using Fiber-Optic Distributed Temperature Sensing

    Science.gov (United States)

    Gryczkowski, L.; Gallion, D.; Haeseker, S.; Bower, R.; Collier, M.; Selker, J. S.; Scherberg, J.; Henry, R.

    2011-12-01

    Salmonids require cool water for all life stages, including spawning and growth. Excessive water temperature causes reduced growth and increased disease and mortality. During the summer, salmonids seek local zones of cooler water as a refuge from elevated temperatures. They also prefer specific habitat features such as boulders and overhanging vegetation. The purpose of this study is to determine whether temperature dynamics or commonly measured fish habitat metrics best explain salmonid abundance. The study site was a 2-kilometer reach of the Walla Walla River near Milton-Freewater, OR, USA, which provides habitat for the salmonids chinook salmon (Oncorhynchus tshawytscha), steelhead/rainbow trout (Oncorhynchus mykiss), mountain whitefish (Prosopium williamsoni), and the endangered bull trout (Salvelinus confluentus). The Walla Walla River is listed as an impaired water body under section 303(d) of the Clean Water Act due to temperature. The associated total maximum daily load (TMDL) calls for temperatures to be below 18 °C at all times for salmonid rearing and migration; however, river temperatures surpassed 24 °C in parts of the study reach in 2009. The two largest factors contributing to the warmer water are reduced riparian vegetation, which decreases shading and increases direct solar radiation, and decreased summer flows caused by diversions and irrigation for agriculture. Fiber-optic distributed temperature sensing has emerged as a unique and powerful tool for ecological applications because of its high spatial and temporal resolution. In this study, meter-scale temperature measurements were obtained at 15-minute intervals along the length of the study reach, allowing for the detection and quantification of cold water inflows during the summer of 2009. The cold water inflows were classified as groundwater or hyporheic sources based on the diurnal temperature patterns. Snorkel surveys were conducted in mid-July and mid-August, 2009 to enumerate salmonid abundance in 23 pools. Fish habitat metrics were quantified for each pool by visual estimation. Regression analysis suggests that temperature-related variables explain fish abundance better than habitat variables, and that salmonids' affinity for cold water refuge may be enhanced following periods of high temperature approaching the lethal threshold.

  7. 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.)

  8. 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

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

    OpenAIRE

    Linec, Matjaz?; Ðonlagic?, 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 amo...

  10. 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.)

  11. 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

  12. The Physics of Fiber Optics

    Science.gov (United States)

    This module, produced by the Wind Technician TV project from Highland Community College, introduces students to the physics of fiber optics. The module consists of four lessons, which are titled: The physics of fiber optics, Fiber optic fundamentals part 1, Fiber optic fundamentals part 2 and Working with plastic fiber optical fiber. Each lesson has a video or animation to explain the concepts involved, and a skill check feature to assess learning and ensure student grasp the concepts before moving on. A PDF accompanies each lesson, with pertinent images and notes from the video or animation.

  13. FOA Lecture 3: Optical Fiber

    Science.gov (United States)

    This is Lecture 3 in the FOA Series on fiber optics. This lecture covers optical fiber, how it works, the types of fiber, fiber specifications, and how it is made. Running time for the lecture is 10:39. Flash is required to view the video.

  14. Integrated optics for fiber optic sensors

    Science.gov (United States)

    Minford, W. J.; Depaula, R. P.

    1991-01-01

    Recent progress achieved in the field of fiber-optic sensor applications is discussed with emphasis placed on LiNbO3-based integrated optics (IO). Particular consideration is given to advanced electromagnetic-field sensors, an integrated laser vibrometer system, and a fiber-optic gyroscope system. It is shown that the multifunction IO chips have enabled high perforamance fiber-optic sensors (e.g., fiber-optic gyros), provided advanced and unique signal processing capabilities and advanced architectures, and have a potential of making fiber-optic sensors at low cost.

  15. Developments in distributed optical fiber detection technology

    Science.gov (United States)

    Ye, Wei; Zhu, Qianxia; You, Tianrong

    2014-12-01

    The distributed optical fiber detection technology plays an important role in many fields, such as key regional security monitoring, pipeline maintenance and communication cable protection. It is superior to the traditional detector, and has a good prospect. This paper presents an overview of various distributed optical fiber sensors. At first, some related technologies of the optical fiber detection schemes are introduced in respect of sensing distance, real-time ability, signal strength, and system complexity; and the advantages and limitations of fiber gratings sensors, reflection-based optical fiber sensors, and interference- based optical fiber sensors are discussed. Then some advanced distributed optical fiber detection systems are mentioned. And the double-loop Sagnac distributed system is improved by adding photoelectric modulators and depolarizers. In order to denoise and enhance the original signal, a spectral subtraction-likelihood ratio method is improved. The experiment results show the spatial resolution is +/-15m per kilometer. Finally, based on the development trends of optical fiber detection technology at home and abroad, development tendency and application fields are predicted.

  16. 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.

  17. Buying Fiber-Optic Networks.

    Science.gov (United States)

    Fickes, Michael

    2003-01-01

    Describes consortia formed by college and university administrators to buy, manage, and maintain their own fiber-optic networks with the goals of cutting costs of leasing fiber-optic cable and planning for the future. Growth capacity is the real advantage of owning fiber-optic systems. (SLD)

  18. 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, ...

  19. 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.

  20. Distributed optical fiber dynamic magnetic field sensor based on magnetostriction.

    Science.gov (United States)

    Masoudi, Ali; Newson, Trevor P

    2014-05-01

    A distributed optical fiber sensor is introduced which is capable of quantifying multiple magnetic fields along a 1 km sensing fiber with a spatial resolution of 1 m. The operation of the proposed sensor is based on measuring the magnetorestrictive induced strain of a nickel wire attached to an optical fiber. The strain coupled to the optical fiber was detected by measuring the strain-induced phase variation between the backscattered Rayleigh light from two segments of the sensing fiber. A magnetic field intensity resolution of 0.3 G over a bandwidth of 50-5000 Hz was demonstrated. PMID:24921868

  1. In-fiber integrated chemiluminiscence online optical fiber sensor.

    Science.gov (United States)

    Yang, Xinghua; Yuan, Tingting; Yang, Jun; Dong, Biao; Liu, Yanxin; Zheng, Yao; Yuan, Libo

    2013-09-01

    We report an in-fiber integrated chemiluminiscence (CL) sensor based on a kind of hollow optical fiber with a suspended inner core. The path of microfluid is realized by etching microholes for inlets and outlets on the surface of the optical fiber without damaging the inner core and then constructing a melted point beside the microhole of the outlet. When samples are injected into the fiber, the liquids can be fully mixed and form steady microflows. Simultaneously, the photon emitted from the CL reaction is efficiently coupled into the core and can be detected at the end of the optical fiber. In this Letter, the concentration of H2O2 samples is analyzed through the emission intensity of the CL reaction among H2O2, luminol, K3Fe(CN)6, and NaOH in the optical fiber. The linear sensing range of 0.1-4.0 mmol/L of H2O2 concentration is obtained. The emission intensity can be determined within 400 ms at a total flow rate of 150 ?L/min. Significantly, this work presents the information of developing in-fiber integrated online analyzing devices based on optical methods. PMID:23988977

  2. Development of sensing coils for an ultraminiaturized tactical fiber gyroscope

    Science.gov (United States)

    Lofts, Cassie M.; Ruffin, Paul B.; Sawyer, Janet G.; Parker, Mike D.

    1994-03-01

    A parametric study has been performed on fiber gyroscope sensing coils to investigate the effects of substantially reducing the inner diameter. Three coils with inner diameters ranging from 6.0 to 1.5 cm were precision-wound with 350 meters of a high-strength, bend-insensitive single mode fiber typically used in Fiber Optic Guided Missile payout systems. Optical loss and extinction ratio measurements were made on the test coils over temperature. The results indicate that the optical loss in the bend-insensitive fiber is not significantly affected by reducing the coil diameter. The fluctuation observed in optical loss during the first thermal cycle is significantly reduced. Extinction ratio data support the theory that the bending-induced birefringence can be significant in single mode fiber wound onto small coils.

  3. 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 ror is included as a practical example. 7 refs., 10 figs

  4. 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

  5. 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)

  6. 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

  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. Distributed flow sensing using optical hot -wire grid.

    Science.gov (United States)

    Chen, Tong; Wang, Qingqing; Zhang, Botao; Chen, Rongzhang; Chen, Kevin P

    2012-04-01

    An optical hot-wire flow sensing grid is presented using a single piece of self-heated optical fiber to perform distributed flow measurement. The flow-induced temperature loss profiles along the fiber are interrogated by the in-fiber Rayleigh backscattering, and spatially resolved in millimeter resolution using optical frequency domain reflectometry (OFDR). The flow rate, position, and flow direction are retrieved simultaneously. Both electrical and optical on-fiber heating were demonstrated to suit different flow sensing applications. PMID:22513536

  9. Fiber optic and laser sensors V; Proceedings of the Meeting, San Diego, CA, Aug. 17-19, 1987

    Science.gov (United States)

    De Paula, Ramon P. (editor); Udd, Eric (editor)

    1988-01-01

    The papers contained in this volume focus on recent developments in fiber optic and laser sensors. Topics discussed include electric and magnetic field sensors, fiber optic pressure sensors, fiber optic gyros, fiber optic sensors for aerospace applications, fiber sensor multiplexing, temperature sensors, and specialized fiber optic sensors. Papers are presented on remote fiber optic sensors for angular orientation; fiber optic rotation sensor for space missions; adaptation of an electro-optic monitoring system to aerospace structures; optical fiber sensor for dust concentration measurements; and communication-sensing system using a single optical fiber.

  10. Fiber optic multimode displacement sensor

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, K.A.; Jarzynski, J. [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States)

    1996-04-01

    An underwater Optical Motion Sensor (OMS) based on a design first presented by W. B. Spillman, {ital Schlieren} {ital multimode} {ital fiber}-{ital optic} {ital hydrophone}, Applied Physics Letters 37(2), 15 July 1980, p. 145{endash}146 is described. The displacement sensor uses the same acoustooptical intensity modulation mechanism as Spillman, however the sensing mechanism is isolated from the ambient fluid environment by a small cylindrical aluminum enclosure (1{double_prime} OD{times}3/4{double_prime}). The enclosure contains an inertial mass and the fiber collimators. The inertial mass is suspended in the center of the enclosure by three small wires rigidly mounted to the walls. The mass and wires act as a cantilever beam system with a mechanical resonance near 100 Hz. The transduction mechanism consists of two opposed optical gratings aligned and positioned between the fiber collimators. One grating is mounted on the inertial mass while the other is mounted on the lower end cap of the enclosure. Relative motion between the gratings causes a modulation of the light transmitted through the gratings. The modulated beam is focused onto a photodetector and converted to electric current. The frequency response is flat from 200 Hz{endash}9 kHz with a minimum detectable displacement of 0.002 A and the dynamic range is 136 dB. The small size and light weight give the sensor an effective density of 1.08 g/cm{sup 3} making it almost neutrally buoyant in water. This in conjunction with the performance characteristics make this sensor suitable for use in acoustical sensing applications. {copyright} {ital 1996 American Institute of Physics.}

  11. 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)

  12. 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

  13. Fiber Optic Testing Course

    Science.gov (United States)

    After completing this self-study program you should learn: What needs testing in fiber optics?What equipment is needed to perform the tests? How are these tests performed? What options exist for performing the tests? How are the tests affected by network types (telco, long haul, LAN, FTTx, etc.)? When testing loss, what is the expected value? How accurate are the tests? How can they be made more accurate? What documentation should be kept on the tests? How is troubleshooting done? How does one write a test plan as part of a SOW (scope of work)? What are common mistakes made in testing? What standards apply to testing and how to use them? This extensive page should be useful for students learning more about testing fiber optic systems.

  14. 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.

  15. Chemical Sensing Using Fiber Cavity Ring-Down Spectroscopy

    Science.gov (United States)

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

    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 types of cavities were coupled to a variety of chemical sensor elements, which are discussed and compared. PMID:22294895

  16. Optical Communication over Plastic Optical Fibers Integrated Optical Receiver Technology

    CERN Document Server

    Atef, Mohamed

    2013-01-01

    This book presents high-performance data transmission over plastic optical fibers (POF) using integrated optical receivers having good properties with multilevel modulation, i.e. a higher sensitivity and higher data rate transmission over a longer plastic optical fiber length. Integrated optical receivers and transmitters with high linearity are introduced for multilevel communication. For binary high-data rate transmission over plastic optical fibers, an innovative receiver containing an equalizer is described leading also to a high performance of a plastic optical fiber link. The cheap standard PMMA SI-POF (step-index plastic optical fiber) has the lowest bandwidth and the highest attenuation among multimode fibers. This small bandwidth limits the maximum data rate which can be transmitted through plastic optical fibers. To overcome the problem of the plastic optical fibers high transmission loss, very sensitive receivers must be used to increase the transmitted length over POF. The plastic optical fiber li...

  17. 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

  18. Modal analysis of layer-structured optical fibers

    OpenAIRE

    Hautakorpi, Markus

    2008-01-01

    Numerical modeling techniques play a key role in the development of new fiber optics, e.g., for telecommunications or sensing applications. In particular, the refractive-index profiles of various specialty optical fibers are increasingly designed with numerical tools. In this thesis, analytical and numerical mode-analysis techniques are applied to layer-structured specialty fibers as well as to partially coherent optical fields. The work is divided into three parts. In the first part, ho...

  19. 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.

  20. Nonlinear optics of microstructure fibers

    Energy Technology Data Exchange (ETDEWEB)

    Zheltikov, Aleksei M [Department of Physics, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

    2004-01-31

    Microstructure fibers have opened a new phase in nonlinear optics. Due to their unique properties, fibers of this type radically enhance all the basic nonlinear-optical phenomena, offering new strategies for frequency conversion, spectral transformation, and control of ultrashort laser pulses. These fibers allow supercontinuum radiation to be efficiently generated using nano- and subnanojoule femtosecond pulses. Here, we analyze the physical mechanisms behind the enhancement of nonlinear-optical interactions of ultrashort pulses in microstructure and hollow photonic-crystal fibers and discuss applications of microstructure fibers for highly efficient supercontinuum generation and frequency conversion of femtosecond laser pulses. (reviews of topical problems)

  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. A phase mask fiber grating and sensing applications

    Directory of Open Access Journals (Sweden)

    Preecha P. Yupapin

    2003-09-01

    Full Text Available This paper presents an investigation of a fabricated fiber grating device characteristics and its applications, using a phase mask writing technique. The use of a most common UV phase laser (KrF eximer laser, with high intensity light source was focussed to the phase mask for writing on a fiber optic sample. The device (i.e. grating characteristic especially, in sensing application, was investigated. The possibility of using such device for temperature and strain sensors is discussed.

  3. System for testing optical fibers

    Science.gov (United States)

    Golob, J.E.; Looney, L.D.; Lyons, P.B.; Nelson, M.A.; Davies, T.J.

    1980-07-15

    A system for measuring a combination of optical transmission properties of fiber optic waveguides. A polarized light pulse probe is injected into one end of the optical fiber. Reflections from discontinuities within the fiber are unpolarized whereas reflections of the probe pulse incident to its injection remain polarized. The polarized reflections are prevented from reaching a light detector whereas reflections from the discontinuities reaches the detector. 2 figs.

  4. Optical fiber network : Cisco part

    OpenAIRE

    Chen, Lu

    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. Electronic Fabrication and Fiber Optics

    Science.gov (United States)

    This pdf contains a syllabus for a course on electronic fabrication and fiber optics as part of the Aerospace Technology Program. The course provides an introduction to basic soldering, crimping, harnessses, and fiber optics as it applies to the aerospace industry with a focus on the space program. Hands on skill training utilizing electronic parts, soldering stations, multimeter, and fiber optic test equipment is a major part of the course.

  6. Fiber optic TV direct

    Science.gov (United States)

    Kassak, John E.

    1991-12-01

    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.

  7. Anisotropic metamaterial optical fibers.

    Science.gov (United States)

    Pratap, Dheeraj; Anantha Ramakrishna, S; Pollock, Justin G; Iyer, Ashwin K

    2015-04-01

    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 such anisotropic circular waveguides can be uncommon Bessel functions with imaginary orders. PMID:25968741

  8. 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.

  9. Fiber optic sensors for process monitoring and control

    Science.gov (United States)

    Marcus, Michael A.

    1991-04-01

    In the past decade a broad range of sensing applications have been reported which utilize optical fiber based sensors. 1''2 These applications range from the measurement of a variety of physical parameters to the quantitative determination of chemical and biochemical species. This paper discusses recent work performed at Eastman Kodak CoiTpany concerning development and testing of fiberoptic sensors in process monitoring and control environments. Topics include sensing mechanisms sensor design environmental considerations and sensor performance characterization in process environments. Sensing mechanisms described inlude optical time domain reflectometer (OTDR) distributed fiber-optic sensing multiplexable reflective fiberpair sensing and photoncorrelation spectroscopy. Distributed fiber-optic sensing applications including temperature pressure strain humidity chemicals and distributed alarms are discussed. Reflective fiberpair sensors described include edge location distance and vibration. Use of photoncorrelation techniques with fiberoptic sensors are also described and process applications of these techniques are presented. 1.

  10. 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

  11. Fiber optics opens window on stream dynamics

    OpenAIRE

    Selker, John; Giesen, Nick; Westhoff, Martijn; Luxemburg, Wim; Parlange, Marc B.

    2006-01-01

    A new approach to monitoring surface waters using distributed fiber optic temperature sensing is presented, allowing resolutions of temperature of 0.01°C every meter along a fiber optic cable of up to 10,000 m in length. We illustrate the potential of this approach by quantifying both stream temperature dynamics and groundwater inflows to the Maisbich, a first-order stream in Luxembourg (49°47?N, 6°02?E). The technique provides a very rich dataset, which may be of interest to many type...

  12. Highly flexible short-pulse generation and high sensitivity sensing with stimulated Brillouin scattering in optical fibers

    Science.gov (United States)

    Lambin Iezzi, Victor; Loranger, Sébastien; Kashyap, Raman

    2014-10-01

    We demonstrate two novel types of applications using the same generator as a source for Brillouin multi-wavelength generation. The first is as a highly flexible picosecond pulsed laser source which is tunable in time duration, repetition rate and emission wavelength for optical clock applications in telecommunication. The second application is a high sensitivity distributed Brillouin sensors (DTS) to lower costs and widens the market sector. We demonstrate tunability of the pulsed laser source from ~15 ps down to ~3.5 ps over the whole telecommunications C-band by simply controlling the number of Stokes waves being generated forming a phase-locked Brillouin frequency comb. The repetition rate is the Brillouin frequency shift of ~10 GHz which can be tuned by changing the gain fiber within the cavity. An increase in the standard temperature sensitivity of DTS of ~1.3 MHz/°C by 6 fold is also demonstrated. This increase is of great importance in DTS, since the detection of any variation can be made faster, which can enhance the functionality of such sensors.

  13. Tackling the limits of optical fiber links

    Science.gov (United States)

    Stefani, Fabio; Lopez, Olivier; Bercy, Anthony; Lee, Won-Kyu; Chardonnet, Christian; Santarelli, Giorgio; Pottie, Paul-Eric; Amy-Klein, Anne

    2015-05-01

    We theoretically and experimentally investigate relevant noise processes arising in optical fiber links, which fundamentally limit their relative stability. We derive the unsuppressed delay noise for three configurations of optical links: two-way method, Sagnac interferometry, and actively compensated link, respectively designed for frequency comparison, rotation sensing, and frequency transfer. We also consider an alternative two-way setup allowing real-time frequency comparison and demonstrate its effectiveness on a proof-of-principle experiment with a 25-km fiber spool. For these three configurations, we analyze the noise arising from uncommon fiber paths in the interferometric ensemble and design optimized interferometers. We demonstrate interferometers with very low temperature sensitivity of respectively -2.2, -0.03 and 1 fs/K. We use one of these optimized interferometers on a long haul compensated fiber link of 540km. We obtain a relative frequency stability of 3E-20 after 10,000 s of integration time.

  14. Fiber-optic accelerometer with hydrophone applications.

    Science.gov (United States)

    Rines, G A

    1981-10-01

    A fiber-optic linear accelerometer based on intensity modulation produced by lateral displacement of a cantilevered fiber has been fabricated and tested. The model reported on is constructed with multimode fiber and has a displacement sensitivity of 6.4 x 10(-13) m. The device has general application as a linear accelerometer with the inherent advantages of remote optical fiber sensing. Particular attention is given to sono-buoy hydrophone applications in which the present model has a sensitivity limit corresponding to 75 dB relative to 1 microPa at 1 kHz. Means for substantially improving the accelerometer's sensitivity as a hydrophone are discussed. PMID:20333170

  15. Tackling the Limits of Optical Fiber Links

    CERN Document Server

    Stefani, Fabio; Bercy, Anthony; Lee, Won-Kyu; Chardonnet, Christian; Santarelli, Giorgio; Pottie, Paul-Eric; Amy-Klein, Anne

    2014-01-01

    We theoretically and experimentally investigate relevant noise processes arising in optical fiber links, which fundamentally limit their relative stability. We derive the unsuppressed delay noise for three configurations of optical links: two-way method, Sagnac interferometry, and actively compensated link, respectively designed for frequency comparison, rotation sensing, and frequency transfer. We also consider an alternative two-way setup allowing real-time frequency comparison and demonstrate its effectiveness on a proof-of-principle experiment with a 25-km fiber spool. For these three configurations, we analyze the noise arising from uncommon fiber paths in the interferometric ensemble and design optimized interferometers. We demonstrate interferometers with very low temperature sensitivity of respectively -2.2, -0.03 and 1 fs/K. We use one of these optimized interferometers on a long haul compensated fiber link of 540km. We obtain a relative frequency stability of 3E-20 after 10,000 s of integration time...

  16. Chemical vapor deposition of anisotropic ultrathin gold films on optical fibers: real-time sensing by tilted fiber Bragg gratings and use of a dielectric pre-coating

    Science.gov (United States)

    Mandia, David J.; Zhou, Wenjun; Ward, Matthew J.; Joress, Howie; Giorgi, Javier B.; Gordon, Peter; Albert, Jacques; Barry, Seán. T.

    2014-09-01

    Tilted fiber Bragg gratings (TFBGs) are refractometry-based sensor platforms that have been employed herein as devices for the real-time monitoring of chemical vapour deposition (CVD) in the near-infrared range (NIR). The coreguided light launched within the TFBG core is back-reflected off a gold mirror sputtered onto the fiber-end and is scattered out into the cladding where it can interact with a nucleating thin film. Evanescent fields of the growing gold nanostructures behave differently depending on the polarization state of the core-guided light interrogating the growing film, therefore the resulting spectral profile is typically decomposed into two separate peak families for the orthogonal S- and P-polarizations. Wavelength shifts and attenuation profiles generated from gold films in the thickness regime of 5-100 nm are typically degenerate for deposition directly onto the TFBG. However, a polarization-dependence can be imposed by adding a thin dielectric pre-coating onto the TFBG prior to using the device for CVD monitoring of the ultrathin gold films. It is found that addition of the pre-coating enhances the sensitivity of the P-polarized peak family to the deposition of ultrathin gold films and renders the films optically anisotropic. It is shown herein that addition of the metal oxide coating can increase the peak-to-peak wavelength separation between orthogonal polarization modes as well as allow for easy resonance tracking during deposition. This is also the first reporting of anisotropic gold films generated from this particular gold precursor and CVD process. Using an ensemble of x-ray techniques, the local fine structure of the gold films deposited directly on the TFBG is compared to gold films of similar thicknesses deposited on the Al2O3 pre-coated TFBG and witness slides.

  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. 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 bot...

  19. Fiber Optic Pulsed Laser Delivery For Remote Measurements

    Science.gov (United States)

    Allison, S. W.; Cates, M. R.; Gillies, G. T.; Noel, B. W.

    1987-06-01

    The results of a research program on the delivery of high-peak-power laser light via fiber optics are presented. We discuss the influence of the host medium and the optical signals on the choice of fiber materials, complemented by a consideration of the measurement environment's effects on the quality of the data. We pay close attention to the choice of input/output beam/fiber coupling optics, nonlinear processes in the core, measurement system noise, and baseline drifts. Useful discussions of pulsed laser damage to optical fibers and data for optimization of a given fiber optic laser beam delivery system are given. As an example, details are given of the optical and instrumentational aspects of a particular fiber optic system developed for remote sensing of pressures and temperatures of UF6 gas in an operating advanced gas centrifuge.

  20. 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.

  1. 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

  2. Single-end simultaneous temperature and strain sensing techniques based on Brillouin optical time domain reflectometry in few-mode fibers.

    Science.gov (United States)

    Weng, Yi; Ip, Ezra; Pan, Zhongqi; Wang, Ting

    2015-04-01

    Recently there is a growing interest in developing few-mode fiber (FMF) based distributed sensors, which can attain higher spatial resolution and sensitivity compared with the conventional single-mode approaches. However, current techniques require two lightwaves injected into both ends of FMF, resulting in their complicated setup and high cost, which causes a big issue for geotechnical and petroleum applications. In this paper, we present a single-end FMF-based distributed sensing system that allows simultaneous temperature and strain measurement by Brillouin optical time-domain reflectometry (BOTDR) and heterodyne detection. Theoretical analysis and experimental assessment of multi-parameter discriminative measurement techniques applied to distributed FMF sensors are presented. Experimental results confirm that FM-BOTDR has similar performance with two-end methods such as FM-BOTDA, but with simpler setup and lower cost. The temperature-induced expansion strain (TIES) in response to different modes is discussed as well. Furthermore, we optimized the FMF design by exploiting modal profile and doping concentration, which indicates up to fivefold enhancement in measurement accuracy. This novel distributed FM-sensing system endows with good sensitivity characteristics and can prevent catastrophic failure in many applications. PMID:25968738

  3. 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.

  4. Stress Sensing by an Optical Fiber Sensor: Method and Process for the Characterization of the Sensor Response Depending on Several Designs

    Directory of Open Access Journals (Sweden)

    Mustapha Remouche

    2013-06-01

    Full Text Available In this paper we propose an analyzing of the response of a stress optical fiber sensor of which we proposed several design. We show that an optical fiber sensor with these designs can covenanting allow the measuring the force/stress applied to a mechanical structure or which it is linked, by optimizing the uses of appropriate materials for constituting the sensor support. The experiment that we introduce to validate our approach based in principles includes design with a support bearing a multimode optical fiber organized in such a way that the transmitted light is attenuated when the fiber-bending angle coming from stitching in holes of the support is modified by the effects of the force/stress applied to the optical fiber sensor realized in this way. The tests realized concern the most relevant parameters that define the performances of the stress sensor that we propose. We present the problems that we to solved for the optimization of the sensor for selecting the more efficient material for the optical fiber sensor support related to a relevant choice of optical fibers.

  5. Fiber optic acoustic sensor technology

    Science.gov (United States)

    Cole, James; Kirkendall, Clay; Dandridge, Anthony

    2005-04-01

    Fiber optic sensor technology has been under development for over 25 years, recently a major milestone has been reached- the introduction of the Fiber Optic Wide Aperture Array on the first Virginia class submarine. This paper will review the development of this technology, outlining the principles of operation and the technological developments that led to fiber optic interferometric sensors becoming viable for production in an advanced sonar system. The Fiber Optic Wide Aperture array is a large channel count planar array mounted on the side of the submarine, but fiber sensor technology is also being developed for both towed arrays (as a replacement for the Navy's thin-line towed arrays) and for bottom mounted acoustic arrays for a number of Navy applications. This paper will describe the development of the fiber optic hydrophones for these applications as well as the optical interrogation techniques. One of the key features of fiber optic sensor technology is the ability to passively multiplex many hydrophone channels per fiber, several multiplexing techniques will also be described. Some of the issues and challenges of this technology, such as coherent noise for large channel count systems will also be briefly discussed.

  6. Combined electromechanical impedance and fiber optic diagnosis of aerospace structures

    Science.gov (United States)

    Schlavin, Jon; Zagrai, Andrei; Clemens, Rebecca; Black, Richard J.; Costa, Joey; Moslehi, Behzad; Patel, Ronak; Sotoudeh, Vahid; Faridian, Fereydoun

    2014-03-01

    Electromechanical impedance is a popular diagnostic method for assessing structural conditions at high frequencies. It has been utilized, and shown utility, in aeronautic, space, naval, civil, mechanical, and other types of structures. By contrast, fiber optic sensing initially found its niche in static strain measurement and low frequency structural dynamic testing. Any low frequency limitations of the fiber optic sensing, however, are mainly governed by its hardware elements. As hardware improves, so does the bandwidth (frequency range * number of sensors) provided by the appropriate enabling fiber optic sensor interrogation system. In this contribution we demonstrate simultaneous high frequency measurements using fiber optic and electromechanical impedance structural health monitoring technologies. A laboratory specimen imitating an aircraft wing structure, incorporating surfaces with adjustable boundary conditions, was instrumented with piezoelectric and fiber optic sensors. Experiments were conducted at different structural boundary conditions associated with deterioration of structural health. High frequency dynamic responses were collected at multiple locations on a laboratory wing specimen and conclusions were drawn about correspondence between structural damage and dynamic signatures as well as correlation between electromechanical impedance and fiber optic sensors spectra. Theoretical investigation of the effect of boundary conditions on electromechanical impedance spectra is presented and connection to low frequency structural dynamics is suggested. It is envisioned that acquisition of high frequency structural dynamic responses with multiple fiber optic sensors may open new diagnostic capabilities for fiber optic sensing technologies.

  7. 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).

  8. Measurement of spontaneous Brillouin scattering in optical fiber with a fiber Bragg grating Sagnac loop

    Science.gov (United States)

    Ou, Zhonghua; Zhang, Lixun; Dai, Zhiyong; Liu, Yongzhi

    2008-04-01

    A novel method for direct optical detection of spontaneous Brillouin scattering in optical fiber by using a fiber Bragg grating (FBG) Sagnac loop is introduced. The transmission character as an optical filter of FBG Sagnac loop is investigated theoretically. The filter which is based on an asymmetric grating Sagnac loop is manufactured and used in the measurement of spontaneous Brillouin scattering sensing system, and the separation of backscattered spontaneous Brillouin from Rayleigh is achieved effectively. It is demonstrated that the fiber grating Sagnac loop filter can be applied in the distributed sensing system based on spontaneous Brillouin scattering.

  9. Fiber optic pressure sensors for nuclear power plants

    International Nuclear Information System (INIS)

    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 pegulatory 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

  10. Refractive index sensing of fiber optic long-period grating structures coated with a plasma deposited diamond-like carbon thin film

    International Nuclear Information System (INIS)

    Long-period grating (LPG) structures including cascaded LPGs on step index fibers and photonic crystal fibers were coated with thin films of diamond-like carbon (DLC) using plasma deposition techniques. Improvements in the coating procedures increased sensitivity to external refractive index variations indicating significant improvements in sensing capability of the hybrid structures. DLC films in the range of tens of nanometers significantly increased sensitivity of all the structures tested

  11. Surface plasmon resonance based fiber optic refractive index sensors

    Science.gov (United States)

    Hlubina, Petr; Kadulova, Miroslava; Ciprian, Dalibor

    2014-12-01

    Refractive index sensors based on surface plasmon resonance (SPR) in a thin metal film deposited on an unclad core of a multimode fiber are presented. The sensing element of the fiber optic SPR sensors is a bare core of a step-index optical fiber made of fused silica with a double-sided sputtered gold film. First, an in-line transmissionbased sensing scheme with the fiber optic SPR probe is used. Second, a reflection-based sensing scheme with a terminated fiber optic SPR probe is employed. The fiber optic SPR probes have different lengths and the thickness of the sputtered gold film is about 50 nm. Both sensing schemes utilize a wavelength interrogation method so that the refractive index of a liquid is sensed by measuring the position of the dip in the transmitted or reflected spectral intensity distribution. As an example, the aqueous solutions of ethanol with refractive indices in a range from 1.333 to 1.364 are measured. For the transmission-based sensing scheme a polarization-dependent response is revealed.

  12. Multiplexed fiber optic displacement sensors

    International Nuclear Information System (INIS)

    A multiplexed bend loss type single-mode fiber-optic sensor system was prepared to measure the displacement of several cm of the civil engineering structures such as many bridges, tunnels and various buildings. This bend loss type fiber-optic sensor used the signal difference between two reflection signals due to various bend losses generating at a pair of optical connectors by using OTDR (optical time domain reflectometer) for measuring displacements. The experiments were conducted for showing the measurement feasibility on the range of 10 cm, and the multiplexing experiments were also performed to measure the displacements of 5 measuring positions of an object by setting these 5 fiber-optic sensors on a single mode fiber simultaneously.

  13. 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.

    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...

  14. 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

  15. 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.

  16. Achieving Optical Fiber Communication Experiments by OptiSystem?

    OpenAIRE

    Alla Abbas Khadir; Baydaa F. Dhahir; Xiquan Fu?

    2014-01-01

    Recently, optical fiber communication technology have made great progress, where has been constantly exploring new technologies has greatly enhanced communications capabilities in the traditional sense, this makes the optical fiber communication technology in a broader context has been applied. Deployment of optical communication systems is costly and reconfiguration is in some cases impossible or uneconomical, therefore the experiments and simulation of systems are has become nec...

  17. Optical Fiber Grating based Sensors

    OpenAIRE

    Michelsen, Susanne; Henningsen, Jes; Kristensen, Martin

    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 ...

  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. 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.

  20. System for testing optical fibers

    Science.gov (United States)

    Davies, Terence J. (Santa Barbara, CA); Franks, Larry A. (Santa Barbara, CA); Nelson, Melvin A. (Santa Barbara, CA)

    1981-01-01

    A system for nondestructively determining the attenuation coefficient, .alpha.(.lambda.), of low-loss optical fiber wave guides. Cerenkov light pulses are generated at a plurality of locations in the fiber by a beam of charged particles. The transit times of selected spectral components and their intensities are utilized to unfold the .alpha.(.lambda.) values over the measured spectrum.

  1. Fiber optic refractive index monitor

    Science.gov (United States)

    Weiss, Jonathan David (Albuquerque, NM)

    2002-01-01

    A sensor for measuring the change in refractive index of a liquid uses the lowest critical angle of a normal fiber optic to achieve sensitivity when the index of the liquid is significantly less than the index of the fiber core. Another embodiment uses a liquid filled core to ensure that its index is approximately the same as the liquid being measured.

  2. Fiber Optics: A Bright Future.

    Science.gov (United States)

    Rice, James, Jr.

    1980-01-01

    Presents an overview of the impact of fiber optics on telecommunications and its application to information processing and library services, including information retrieval, news services, remote transmission of library services, and library networking. (RAA)

  3. Fiber optic multiplex optical transmission system

    Science.gov (United States)

    Bell, C. H. (inventor)

    1977-01-01

    A multiplex optical transmission system which minimizes external interference while simultaneously receiving and transmitting video, digital data, and audio signals is described. Signals are received into subgroup mixers for blocking into respective frequency ranges. The outputs of these mixers are in turn fed to a master mixer which produces a composite electrical signal. An optical transmitter connected to the master mixer converts the composite signal into an optical signal and transmits it over a fiber optic cable to an optical receiver which receives the signal and converts it back to a composite electrical signal. A de-multiplexer is coupled to the output of the receiver for separating the composite signal back into composite video, digital data, and audio signals. A programmable optic patch board is interposed in the fiber optic cables for selectively connecting the optical signals to various receivers and transmitters.

  4. Light diffusing fiber optic chamber

    Science.gov (United States)

    Maitland, Duncan J. (Lafayette, CA)

    2002-01-01

    A light diffusion system for transmitting light to a target area. The light is transmitted in a direction from a proximal end to a distal end by an optical fiber. A diffusing chamber is operatively connected to the optical fiber for transmitting the light from the proximal end to the distal end and transmitting said light to said target area. A plug is operatively connected to the diffusing chamber for increasing the light that is transmitted to the target area.

  5. Fiber optics for advanced aircraft

    Science.gov (United States)

    Baumbick, Robert J.

    1989-01-01

    The increased use of composites makes the digital control more susceptible to electromagnetic effects. In order to provide the protection to the digital control additional shielding will be required as well as protective circuitry for the electronics. This results in increased weight and reduced reliability. The advantages that fiber optic technology provides for advanced aircraft applications is recognized. The use of optical signals to carry information between the aircraft and the control module provides immunity from contamination by electromagnetic sources as well as other important benefits such as reduced weight and volume resulting from the elimination of the shielding and the replacement of metal conductors with low weight glass fibers. In 1975 NASA began work to develop passive optical sensors for use with fiber optics in aircraft control systems. The problem now is to choose the best optical sensor concepts and evaluate them for use. In 1985 NASA and DOD entered into a joint program, Fiber Optic Control System Integration (FOCSI), to look at optical technology specifically for use in advanced aircraft systems. The results of this program are discussed. The conclusion of the study indicated that the use of fiber optic technology in advanced aircraft systems is feasible and desirable. The study pointed to a lack of available sensors from vendors capable of operating in the adverse environments of advanced aircraft.

  6. Femtosecond laser microprocessing for implanting sensor function into optical fibers

    Science.gov (United States)

    Goya, Kenji; Tokita, Daisaku; Watanabe, Kazuhiro

    2010-09-01

    The purpose of this study is to fabricate an internal structure in a silica fiber using internal processing with a femtosecond laser to develop a novel optical fiber sensor. We have found that bending directions can be detected by measuring transmitted light that has been affected from non-axial symmetry-sensing region in our proposed optical fiber sensor. In this paper, an optical fiber-processing experiment is carried out with the intensity of light transmitted through the sensing region being measured so that light loss through internal processing is measured. In the processing experiment, it was confirmed that use of a Ti:sapphire laser results in a processed region inside the fiber. In the measurement experiment, light transmitted through the core of a processed fiber was measured when the fiber was bent toward the processed region and when the fiber was bent toward the other side. The intensity of transmitted light obtained was found to be dependent on the two bending directions. This indicates that detection of the bending direction is possible. Experimental results are presented for the optimum irradiation parameters for internal processing of optical fibers for the fabrication of various required dot structures in the vicinity of the fiber core surface. We also report measurement experiment for the processed fiber.

  7. Recent Developments Of Optical Fiber Sensors For Automotive Use

    Science.gov (United States)

    Sasayama, Takao; Oho, Shigeru; Kuroiwa, Hiroshi; Suzuki, Seikoo

    1987-12-01

    Optical fiber sensing technologies are expected to apply for many future electronic control systems in automobiles, because of their original outstanding features, such as high noise immunity, high heat resistance, and flexible light propagation paths which can be applicable to measure the movements and directions of the mobiles. In this paper, two typical applications of fiber sensing technologies in automobiles have been described in detail. The combustion flame detector is one of the typical applications of a fiber spectroscopic technology which utilizes the feature of high noise and heat resistibility and remote sensibility. Measurements of engine combustion conditions, such as the detonation, the combustion initiation, and the air-fuel ratio, have been demonstrated in an experimental fiber sensing method. Fiber interferometers, such as a fiber gyroscope, have a lot of possibilities in future mobile applications because they are expandable to many kinds of measurements for movements and physical variables. An optical fiber gyroscope utilizing the single polarized optical fiber and optical devices has been developed. Quite an accurate measurement of vehicle position was displayed on a prototype navigation system which installed the fiber gyroscope as a rotational speed sensor.

  8. The fiber optic probe hydrophone

    OpenAIRE

    Wurster, Clemens; Staudenraus, Joachim; Eisenmenger, Wolfgang

    1994-01-01

    We present a new type of hydrophone based on a fiber-optic sensor principle for shock wave and ultrasonic measurements in water. Its detection mechanism is based on the change of the optical reflection coefficient at the end surface of a glass fiber in water by pressure signals. The relation between the intensity of the reflected light and the water pressure is defined by material constants so that calibration by reference is not necessary. Shock wave measurements were made with the fiber opt...

  9. 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.

  10. Fiber optic Adaline neural networks

    Science.gov (United States)

    Ghosh, Anjan K.; Trepka, Jim; Paparao, Palacharla

    1993-02-01

    Optoelectronic realization of adaptive filters and equalizers using fiber optic tapped delay lines and spatial light modulators has been discussed recently. We describe the design of a single layer fiber optic Adaline neural network which can be used as a bit pattern classifier. In our realization we employ as few electronic devices as possible and use optical computation to utilize the advantages of optics in processing speed, parallelism, and interconnection. The new optical neural network described in this paper is designed for optical processing of guided lightwave signals, not electronic signals. We analyzed the convergence or learning characteristics of the optically implemented Adaline in the presence of errors in the hardware, and we studied methods for improving the convergence rate of the Adaline.

  11. 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.

  12. Temperature sensing in multiple zones based on Brillouin fiber ring laser

    Energy Technology Data Exchange (ETDEWEB)

    Galindez, C A; Madruga, F J; Ullan, A; Lopez-Higuera, J M [Photonics Engineering Group, Universidad de Cantabria, Av Castros s/n, 39005-Santander (Spain); Lopez-Amo, M, E-mail: galindezca@unican.e [Depto. IngenierIa Electrica y Electronica, Universidad Publica de Navarra, Campus de Arrosadia s/n, 31006 Pamplona (Spain)

    2009-07-01

    A simple system for sensing temperature in multiple zones based on a multi-wavelength Brillouin fiber laser ring is presented. Optical fiber reels are serially concatenated and divided in zones (one per sensing area). Setting the Brillouin lasing in each spool of fiber generates a characteristic wavelength that depends on the fiber properties and the temperature in the zone. Thus, it is possible to measure temperature independently and accurately through heterodyne detection between two narrow laser signals. The proposed sensor integrates the temperature along the whole spool of fiber in each zone. These real time measurements were successfully checked in our laboratory.

  13. Demonstration of a refractometric sensor based on an optical micro-fiber three-beam interferometer

    OpenAIRE

    Han, Chunyang; Ding, Hui; Lv, Fangxing

    2014-01-01

    With diameter close to the wavelength of the guided light and high index contrast between the fiber and the surrounding, an optical micro-fiber shows a variety of interesting waveguiding properties, including widely tailorable optical confinement, strong evanescent fields and waveguide dispersion. Among various micro-fiber applications, optical sensing has been attracting increasing research interest due to its possibilities of realizing miniaturized fiber optic sensors with small footprint, ...

  14. Laser-Pulse/Fiber-Optic Liquid-Leak Detector

    Science.gov (United States)

    Padgett, M. E.

    1986-01-01

    Several potential leak sites monitored using single sensing fiber. Fluid systems monitored quickly for leaks in remote, hazardous, or inaccessible locations by system of compact, lightweight fiber-optic leak sensors presently undergoing development. Sensors installed at potential leak sites as joints, couplings, and fittings. Sensor read by sending laser pulse along fiber, then noting presence or relative amplitude of return pulse. Leak-monitoring technique applicable to wide range of fluid systems and minimizes human exposure to toxic or dangerous fluids.

  15. Monolithic fiber optic sensor assembly

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. Modulation in optical fiber lasers using polarization feedback

    Science.gov (United States)

    Hernández-Cordero, Juan; Cuando-Espitia, Natanael

    2007-09-01

    Modulated optical fiber laser sources have proven useful in applications ranging from fiber communications systems to optical fiber sensors. As with many other coherent light sources, fiber lasers can easily be modulated by means of electro-optical devices; several modulation schemes have been successfully reported. In this paper, we report on a fiber laser with modulation regimes achieved by means of polarization feedback. The all-fiber laser cavity is based on a Fabry-Perot arrangement in which single or dual polarization output can be obtained upon adjusting the intra-cavity birefringence. Feedback of one polarization yields several effects on the population dynamics of the fiber laser, thereby providing a simple way of achieving a dual polarization modulated output. Monitoring of both polarization modes show that during modulation, polarization dynamics can exhibit in-phase and anti-phase behavior, and for pump power levels well above threshold, chaotic-like behavior can also be observed. Experiments show that the modulated regime obtained with the fiber laser depends on operating parameters such as pump power level, intra-cavity birefringence and the phase of the polarized mode used as a feedback signal. As shown through radio-frequency spectral analysis, the proposed arrangement could provide a simple polarimetric sensing scheme with radio-frequency readout for fiber optic sensors. Finally, we discuss the use of the proposed fiber laser in applications such as polarization-switched sensing and self-mixing interferometry.

  17. 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 carryingages 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

  18. 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.

  19. Tapered optical fibres for sensing

    Science.gov (United States)

    Martan, Tomas; Kanka, Jiri; Kasik, Ivan; Matejec, Vlastimil

    2008-11-01

    Recently, optical fibre tapers have intensively been investigated for many applications e.g. in telecommunications, medicine and (bio-) chemical sensing. The paper deals with enhancement of evanescent-field sensitivity of the solid-core microstructured fibre with steering-wheel air-cladding. Enhancement of a performance of the microstructured fibre is based on reduction of fibre core diameter down to narrow filament by tapering thereby defined part of light power is guided by an evanescent wave traveling in axial cladding air holes. The original fibre structure with outer diameter of 125 µm was reduced 2×, 2.5×, 3.33×, and 4× for increasing relatively small intensity overlap of guided core mode at wavelength of 1.55 ?m with axial air holes. The inner structures of tapered microstructured fibre with steering-wheel aircladding were numerically analyzed and mode intensity distributions were calculated using the FDTD technique. Analyzed fiber tapers were prepared by constructed fibre puller employing 'flame brush technique'.

  20. Online fiber-optic photometer

    International Nuclear Information System (INIS)

    The development and implementation of a fiber-optic photometer for process control at the Savannah River Plant (SRP) will be discussed. The instrument is a modified Du Pont 400 photometric analyzer which incorporates quartz fiber-optic cables, a high-intensity tungsten-halogen lamp source, and a sight glass with sealed optics. Six of these photometers have been installed at SRP to monitor the elution of neptunium or plutonium from anion exchange columns. The fiber optics allow the instrument to be located 50 feet from the sight glass, which is in a highly radioactive area. This ensures easy access to the instrument and minimizes radiation exposure to personnel. The modifications to the analyzer and its application to process control will be presented

  1. Fiber optic spectrochemical emission sensors

    International Nuclear Information System (INIS)

    Prior work on fiber optic spectrochemical emission sensor (FOSES) concepts has been extended to the design and fabrication of a prototype fiber optic chemical sensor system for chlorinated compounds. The sensor performs analyte dissociation and atomic excitation via a radio-frequency-excited helium plasma. The device has been configured for field measurements of vadose-zone concentrations of carbon tetrachloride on the Hanford Reservation in southeastern Washington state. Detection and quantification of other atomic species may be achieved by varying the analytical wavelength. The sensor system design incorporates and RF excitation source: a metered, sub-atmospheric pressure helium supply system; and optical detection system; and a fiber optic umbilical to transmit analyte emissions to a central detection/data acquisition system. Sensor system design is summarized as well as performance data relating to detection limits and dynamic range

  2. Optical fiber acousto-optic phase modulators

    Science.gov (United States)

    Roeksabutr, Athikom

    1998-08-01

    Although optical fiber acousto-optic phase modulators using piezoelectric ZnO coating have been widely investigated for a decade, the exact theory of high frequency modulation for this device structure has rarely been studied in great detail. Moreover, reports on optical phase modulation in the microwave frequency region are few in number. This thesis reports on an intensive study of such a device in both theoretical modelling and experimental demonstrations. It includes the acoustic transducer and acousto-optic phase modulator. The technique of thin-film deposition is described. The development of a DC magnetron sputtering system for device fabrication is explained in detail. The fabrication procedure and device assembly are also mentioned. Acoustic transducers using piezoelectric ZnO coating on the fiber surface were successfully fabricated for the coupling of high frequency acoustic waves into optical fibers in the region of a few hundred MHz to over 1 GHz. The electrical models based on the actual structure of an acoustic resonator structure for each layer and the resonator itself are presented in full detail. The validity of this model is confirmed by the S11-parameter measurement of the practical devices. In comparison with the well-known Mason model, this model exhibits an asymmetrical property due to the different radii of curvature at each side of the thin layer. By using this model, the device performance in various parameters has been investigated for transducer design consideration. The comprehensive theory of optical fiber acousto-optic phase modulators is presented. Optical phase modulation results from both axial and radial strains induced by acoustic waves in the fiber. The phase modulation up to almost 1 GHz has been demonstrated with the maximum phase shift of 0.7 radians. The theoretical calculation expresses good agreement in comparison with the experimental results. This theoretical model is useful in the device design for many applications. A novel microwave frequency optoelectronics tone decoder system has been theoretically proposed. The device utilizes the properties of a fiber ring resonator at the resonance condition and of an optical fiber acousto-optic phase modulator in the fiber loop. The functioning of the system is confirmed by theoretical calculation using practical parameters.

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

    OpenAIRE

    Sayde, C.; Gregory, C.; Gil-rodriguez, M.; Tufillaro, N.; Tyler, S.; 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...

  4. 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.

  5. Development of a 2-Channel Embedded Infrared Fiber-Optic Temperature Sensor Using Silver Halide Optical Fibers

    Directory of Open Access Journals (Sweden)

    Bongsoo Lee

    2011-10-01

    Full Text Available A 2-channel embedded infrared fiber-optic temperature sensor was fabricated using two identical silver halide optical fibers for accurate thermometry without complicated calibration processes. In this study, we measured the output voltages of signal and reference probes according to temperature variation over a temperature range from 25 to 225 °C. To decide the temperature of the water, the difference between the amounts of infrared radiation emitted from the two temperature sensing probes was measured. The response time and the reproducibility of the fiber-optic temperature sensor were also obtained. Thermometry with the proposed sensor is immune to changes if parameters such as offset voltage, ambient temperature, and emissivity of any warm object. In particular, the temperature sensing probe with silver halide optical fibers can withstand a high temperature/pressure and water-chemistry environment. It is expected that the proposed sensor can be further developed to accurately monitor temperature in harsh environments.

  6. Multimode optical fiber based spectrometers

    CERN Document Server

    Redding, Brandon; Cao, Hui

    2013-01-01

    A standard multimode optical fiber can be used as a general purpose spectrometer after calibrating the wavelength dependent speckle patterns produced by interference between the guided modes of the fiber. A transmission matrix was used to store the calibration data and a robust algorithm was developed to reconstruct an arbitrary input spectrum in the presence of experimental noise. We demonstrate that a 20 meter long fiber can resolve two laser lines separated by only 8 pm. At the other extreme, we show that a 2 centimeter long fiber can measure a broadband continuous spectrum generated from a supercontinuum source. We investigate the effect of the fiber geometry on the spectral resolution and bandwidth, and also discuss the additional limitation on the bandwidth imposed by speckle contrast reduction when measuring dense spectra. Finally, we demonstrate a method to reduce the spectrum reconstruction error and increase the bandwidth by separately imaging the speckle patterns of orthogonal polarizations. The mu...

  7. All-optical storage and processing in optical fibers

    OpenAIRE

    Thévenaz, Luc; Primerov, Nikolay; Chin, Sanghoon; Antman, Yair; Denisov, Andrey; Zadok, Avi; Santagiustina, Marco

    2012-01-01

    The recent possibility to generate and read dynamic Bragg gratings in optical fibers by the interaction of multiple optical waves through stimulated Brillouin scattering has opened a new field to realize all-optical fiber-based functions.

  8. 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

  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. Optical fiber beam loss monitor

    International Nuclear Information System (INIS)

    We have been developed an arc sensor with high sensitivity since 2007. When the arc sensor was installed into the cavity coupler located in the beam tunnel, it is found that an arc sensor reacted to beam loss sensitively. This is because Cherenkov light occurs in the optical fiber by the charged particle. This means that the state of the beam loss can be detected by observing the Cherenkov light. Large-diameter optical fibers were set into the acceleration structures and vacuum ducts. We observed light from an optical fiber by the photo-multiplier tube (PMT). When we observed light from the upstream, we can identify the point of the beam loss in position resolution of 8.3 nsec/m. We observed beam loss at various points of the Linac. (author)

  11. 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.

  12. 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.

  13. A fiber-optic hydrophone with an acoustic filter

    Science.gov (United States)

    Wang, Zefeng; Hu, Yongming; Meng, Zhou; Ni, Ming; Luo, Hong

    2007-11-01

    A novel Michelson interferometric fiber-optic hydrophone with a mechanical anti-aliasing acoustic filter, which consists of a two-hole cylindrical Helmholtz resonator, has been manufactured and tested. Experimental results show that this new fiber-optic hydrophone has a function of acoustic low-pass filtering. The low frequency sensitivity, as determined by the fiber interferometer and the sensing mandrel, is about -159dB re 1rad/?Pa. The frequency response has a break point near 1200Hz and a measured roll-off of 50dB/octave. The fiber-optic hydrophone is a prototype device for a class of sensors that used to eliminate aliasing in the future sonar systems. To our knowledge, this is the first time that such a fiber-optic hydrophone has been reported.

  14. Report on a simultaneous ion viscosity, strain and impedance measurement technique using a novel integrated dielectric, optical fiber and piezoelectric sensing element for the online characterization of smart structures

    Science.gov (United States)

    Talaie, A.; Kosaka, T.; Oshima, N.; Osaka, K.; Asano, Y.; Fukuda, T.

    2001-04-01

    This paper reports on a simultaneous ion viscosity, strain and impedance (SISI) system in order to measure the physical and chemical properties of composites during their curing process. The SISI system uses an integrated multi-sensing element, entitled DOP, that is comprised of dielectric (D), optical fiber (O) and piezoelectric (P) sensors. This system was used to measure several data simultaneously in real time and in situ. The results clearly show that there is a direct relationship between the ion viscosity, impedance and strain changes during the curing process. It was found that dielectric sensor is very sensitive to physical and chemical changes of the composite both in the heating and cross-linking periods. The piezoelectric proved to be a useful element during the heating period with a very sensitive and surprising behavior during the cooling period. The optical fiber also demonstrated a very striking profile in strain variations during cooling.

  15. 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

  16. Selective Serial Multi-Antibody Biosensing with TOPAS Microstructured Polymer Optical Fibers

    DEFF Research Database (Denmark)

    Emiliyanov, Grigoriy Andreev; HØiby, Poul E.

    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.

  17. 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)

  18. 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.

  19. Fiber-optical microphones and accelerometers based on polymer optical fiber Bragg gratings : [invited

    DEFF Research Database (Denmark)

    Yuan, Scott Wu Technical University of Denmark,

    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 accelerometer. The specs are compared to the specs obtained when using Silica FBGs.

  20. Rayleigh backscatter mitigation by RF modulation in a 100-km remote fiber sensing system

    Science.gov (United States)

    Chow, Jong H.; McClelland, David E.; Gray, Malcolm B.

    2007-04-01

    One of the main factors limiting high performance remote fiber sensing systems is the Rayleigh backscatter associated with a long length of optical delivery fiber. Rayleigh backscatter introduces amplitude and phase noise during interferometric signal extraction, resulting in degradation of system sensitivity. This noise source increases with the length of optical fiber used in the architecture, and thus traditionally sets the lower limit on signal strength and the total remote sensing distance. We present the latest results for a 100 km remote fiber dynamic strain sensing system, where a radio-frequency (RF) modulated laser is used to interrogate a fiber Fabry- Perot sensor. The signal extraction is derived interferometrically from the differential phase between the carrier and its RF sidebands. We demonstrate unprecedented remote sensitivity performance by complete mitigation of the debilitating effects associated with Rayleigh backscatter in the 100 km of optical delivery fiber. We show that optimization of the laser modulation depth, as well as fiber Fabry-Perot design both facilitate a large signal-to-noise ratio. This maximized signal-to-noise ratio enables the complete suppression of the noise associated with Rayleigh backscatter. The result is a long-distance remote fiber sensing system that is limited only by the laser frequency noise. This remote sensitivity is an important breakthrough for a range of applications, such as sea floor acoustic sensing arrays, deep sea hydrophone arrays, and remote surveillance arrays.

  1. Catching Attention in Fiber Optics Class

    OpenAIRE

    Kezerashvili, R. Ya; Leng, L.

    2004-01-01

    Following a brief review on the history and the current development of fiber optics, the significance of teaching fiber optics for science and non-science major college students is addressed. Several experimental demonstrations designed to aid the teaching and learning process in fiber optics lectures are presented. Sample laboratory projects are also proposed to help the students to understand the physical principles of fiber optics.

  2. Laser and Fiber Optics Student Resources

    Science.gov (United States)

    This page from Laser-Tec, the Laser and Fiber Optics Regional Center, contains resources for students considering a career in lasers and fiber optics. First, lasers and fiber optics are defined and example applications are listed. Next, a list of laser and fiber optics technician jobs is presented along with a short description of what tasks these jobs perform. Lastly, external links are provided to educational resources.

  3. 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.

  4. 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

  5. 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.

  6. Fiber optic and laser sensors IX; Proceedings of the Meeting, Boston, MA, Sept. 3-5, 1991

    Science.gov (United States)

    Depaula, Ramon P. (editor); Udd, Eric (editor)

    1991-01-01

    The present volume on fiber-optic and laser sensors discusses industrial applications of fiber-optic sensors, fiber-optic temperature sensors, fiber-optic current sensors, fiber-optic pressure/displacement/vibration sensors, and generic fiber-optic systems. Attention is given to a fiber-sensor design for turbine engines, fiber-optic remote Fourier transform IR spectroscopy, near-IR fiber-optic temperature sensors, and an intensity-type fiber-optic electric current sensor. Topics addressed include fiber-optic magnetic field sensors based on the Faraday effect in new materials, diaphragm size and sensitivity for fiber-optic pressure sensors, a microbend pressure sensor for high-temperature environments, and linear position sensing by light exchange between two lossy waveguides. Also discussed are two-mode elliptical-core fiber sensors for measurement of strain and temperature, a fiber-optic interferometric X-ray dosimeter, fiber-optic interferometric sensors using multimode fibers, and optical fiber sensing of corona discharges.

  7. Optical fibers and RF a natural combination

    CERN Document Server

    Romeiser, Malcolm

    2004-01-01

    The optical fiber industry has experienced a period of consolidation and reorganization and is now poised for a new surge in growth. To take advantage of that growth, and to respond to the demand to use fiber more efficiently, designers need a better understanding of fiber optics. Taking the approach that optical fibers are an extension of RF-based communications, the author explains basic optical concepts, applications, and systems; the nature and performance characteristics of optical fibers; and optical sources, connectors and splices. Subsequent chapters explore current applications of fib

  8. 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

  9. Radiation characteristics of optical fibers

    International Nuclear Information System (INIS)

    Recently, the radiation characteristics of various optical fibers have been examined, but those of single mode fibers have been rarely reported. The authors examined the radiation characteristics of the single mode fibers prepared by VAD (vapor axial deposition) method to compare them with those of multi-mode fibers. The fibers prepared are: (A) Ge-doped quartz glass core, highly pure quartz glass clad and (B) OH-doped quartz glass core, F-doped quartz glass clad as the single mode fibers, and (C) Ge and P-doped quartz glass core and quartz glass clad and (D) Ge-doped quartz glass core and quartz glass clad as the GI fibers. Those were irradiated with 60Co ?-ray at 2.7 x 104 rad/h to examine the increase of loss. For the element fibers of these, the loss spectra in infrared region were also measured with a monochromator after they had been left for 4 hours in a furnace at 200 deg C through which only hydrogen gas flowed and cooled. Both the samples (A) and (B) increased the loss with the increase of radiation dose, and the increase tended to saturate at 5 x 105 Rad. The radiation characteristics of the sample (B) were inferior, and this was the exact opposite to the result which has so far been obtained in multi-mode fibers. The increase of loss at 850 nm in the sample (C) was about 17 times as large as the sample (D) in the results for the GI fibers. This shows that the effect of phosphorus was more remarkable than that of germanium s more remarkable than that of germanium because the Ge content in both samples (C) and (D) was almost the same. (Wakatsuki, Y)

  10. 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.

  11. 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…

  12. FOA Lecture 1: Fiber Optics & Communications

    Science.gov (United States)

    Hayes, Jim

    This is the first of a series of short lectures on fiber optics by Jim Hayes, president of the Fiber Optic Association. This lecture covers how fiber optics are used in various types of systems such as telecommunications, CATV, security and Smart Grid. Running time for the lecture is 12:21. Flash is required to view the video.

  13. Optically powered fiber networks

    OpenAIRE

    Roger, M.; Bo?ttger, G.; Dreschmann, M.; Klamouris, C.; Hu?bner, M.; Bett, A. W.; Becker, J.; Freude, W.; Leuthold, J.

    2008-01-01

    Optically powered networks are demonstrated. Heterogeneous subscribers having widely varying needs with respect to power and bandwidth can be effectively controlled and optically supplied by a central office. The success of the scheme relies both on power-efficient innovative hardware and on a novel low-energy medium access control protocol. We demonstrate a sensor network with subscribers consuming less than 1 mu W average power, and an optically powered high-speed video link transmitting da...

  14. 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

  15. Speckle characterization in multimode fibers for sensing applications

    Science.gov (United States)

    Rodriguez-Cobo, Luis; Lomer, Mauro; Galindez, Carlos; Lopez-Higuera, J. M.

    2012-10-01

    This paper proposes the characterization of speckle patterns of multimode fibers in view of sensing applications and particularly for detection of vibration or seismic activity. Plastic optical fibers are used in this work due to its excellent flexibility and adaptability to build sensor heads. We are interested in the response to vibration, for which we use a short cylindrical piezoelectric transducer (PZT) vibrating in radial direction. The multimode fiber was coiled as tightly as possible around the mandrel of the PZT and periodic stretching effect was caused by the radial oscillations of the actuator. The PZT is modulated with a frequency generator by applying a sinusoidal signal in the range of 0 to 20 Hz, so the speckle patterns can be time averaged. The fiber extreme is attached to a high speed camera with a plastic adaptor, centering the speckle pattern into the CCD. Maintaining the fiber position, a region of interest is selected to capture the video sequence and it is captured to detect the variations in the speckle pattern. Once having the video sequence, it is processed by averaging the pixel differences between two consecutive frames. This processed sequence is also filtered in order to reduce the high frequency noise component. In this work we report the results of the characterization of 3 types of multimode fibers, with core diameters of 50 μm, 240 μm and 980 μm.

  16. Temperature sensing by using whispering gallery modes with hollow core fibers

    International Nuclear Information System (INIS)

    We describe temperature sensing by hollow core fibers using whispering gallery modes of a spherical microresonator. Light from a tunable laser was coupled into the input end of the hollow core fiber. Optical resonances were excited in a microsphere inserted in the modified output end. Part of the light was coupled back from the resonator into the hollow core fiber and transported back to the input end. This light was recorded via a beam splitter by a diode. The sensing principle is based on the shift of the optical resonances by changing the temperature of the resonator. This shift is monitored and leads to the temperature of the resonator and surrounding respectively

  17. Fiber Optic Pressure Sensor Design Considerations And Evaluation

    Science.gov (United States)

    Hong, LiLi; Nara, Andren R.; Prohaska, Otto J.

    1989-08-01

    A new type of fiber optic pressure transducer has been developed and tested for biomedical application. It consists of two parts: a pressure-sensing membrane and a fiber optic displacement transducer which is based on the light intensity loss caused by angular misalignment between two fibers. The light intensity change is registered by a photodiode. The pressure transducer has been evaluated for static and dynamic pressure measurements. Not only does it have adequate linearity and frequency response and is safe and small in size, but it also may be an attractive device for designing catheters for multiple site static pressure detection.

  18. Laser and Fiber Optics Curriculum Resources

    Science.gov (United States)

    This page from Laser-Tec, the Laser and Fiber Optics Regional Center, contains links to resources for educators to use in instruction on lasers and fiber optics. These include curriculum materials from OP-TEC, SPIE Hands-On Optics, Practical Optics & Photonics Education Tools, and Fiber U Online learning website. Additionally, Laser-Tec is developing a "compact and low-cost optics toolkit that will include laboratory manual and video demonstrations."

  19. High resolution underwater fiber optic threat detection system

    Science.gov (United States)

    Berger, Alexander; Hermesh, Shalmon; Durets, Eugene; Kempen, Lothar U.

    2006-10-01

    Current underwater protection systems are complex expensive devices consisting of multiple electronic sensing elements. The detection and identification of divers and small submerged watercraft requires very high image resolution. The high price of an array of conventional piezoelectric transducers and associated electronic components makes this solution feasible for localized implementations, but the protection of large stretches of coastline requires a different approach. We present a novel multichannel sonar design that augments current active sonar transducers with a passive fiber-optic multichannel acoustic emission sensing array. The system provides continuous monitoring of the acoustic wave reflections emitted by a single projector, yielding information about the size and shape of approaching objects. A novel fiber hydrophone enclosure is utilized to dramatically enhance the sensor response to the sonar frequency, while suppressing out-of-band sound sources and noise. The ability of a fiber hydrophone to respond to acoustic emissions is based on established fiber Bragg grating sensing techniques. In this approach, the energy of an acoustic wave is converted into the modulation of the in-fiber optical transducer's optical properties. The obtained results demonstrate significant response of the designed fiber optic hydrophone to the incident acoustic wave over the frequency domain from 1-80 kHz. Our approach allows selective tuning of the sensor to a particular acoustic frequency, as well as potential extension of the spectral response to 300- 400kHz.2

  20. 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)

  1. Distributed fiber sensing using Brillouin echoes

    OpenAIRE

    The?venaz, Luc; Foaleng, Stella M.

    2008-01-01

    A simple physical description of the nonlinear optical interaction based on Brillouin echoes is presented. This technique makes potentially possible distributed Brillouin sensing down to centimeter spatial resolution while preserving the narrowband feature of the natural Brillouin gain spectrum. Experimental conditions for the generation of Brillouin echoes are described and demonstrations of distributed measurements using a 1 ns (10 cm) pulse are presented.

  2. Artificially disordered birefringent optical fibers.

    Science.gov (United States)

    Herath, S; Puente, N P; Chaikina, E I; Yamilov, A

    2012-02-13

    We develop and experimentally verify a theory of evolution of polarization in artificially-disordered multi-mode optical fibers. Starting with a microscopic model of photo-induced index change, we obtain the first and second order statistics of the dielectric tensor in a Ge-doped fiber, where a volume disorder is intentionally inscribed via UV radiation transmitted through a diffuser. A hybrid coupled-power & coupled-mode theory is developed to describe the transient process of de-polarization of light launched into such a fiber. After certain characteristic distance, the power is predicted to be equally distributed over all co-propagating modes of the fiber regardless of their polarization. Polarization-resolved experiments, confirm the predicted evolution of the state of polarization. Complete mode mixing in a segment of fiber as short as ? 10cm after 3.6dB insertion loss is experimentally observed. Equal excitation of all modes in such a multi-mode fiber creates the conditions to maximize the information capacity of the system under e.g. multiple-input-multiple-output (MIMO) transmission setup. PMID:22418121

  3. FOA Lecture 4: Fiber Optic Cables

    Science.gov (United States)

    Hayes, Jim

    This is the 4th lecture on fiber optics by Jim Hayes, president of the Fiber Optic Association. This lecture covers fiber optic cables. Cables are used to protect the fibers in the installation environment, outdoors or indoors. In this lecture, Hayes covers the requirements of cables for various applications and the types of cables typically used. Running time for the lecture is 10:15. Flash is required to view the video.

  4. 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...

  5. 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.

  6. Robust fiber optic sensors for process monitoring and control applications

    Science.gov (United States)

    Marcus, Michael A.

    1996-12-01

    In the past decade a broad range of sensing applications have been reported utilizing optical-fiber-based sensors. These applications range from the measurement of a variety of physical parameters to the quantitative determination of chemical and biochemical species. The acceptance of many of these sensors by the process monitoring and control industry has not met manufacturer's expectations. This paper describes the special requirements and concerns which must be addressed in implementing fiber-optic sensors in process environments. Topics include sensor specificity and interferences, environmental constraints, long term stability, sensor calibration methods, sensing mechanisms, sensor system design for self-calibration, and performance characterization in process environments. Special requirements for single point and distributed fiber-optic sensing applications including temperature, pressure, strain, humidity, and chemical concentration are described. Methods are discussed for designing robust fiber-optic sensors which remain calibrated for extended periods of time. Also included is a discussion of self calibration methods for use in reflective mode intensity, analyte and distributed based fiber-optic sensors.

  7. Interferometric fiber optic displacement sensor

    Science.gov (United States)

    Farah, John (M.I.T. P.O. Box 397301, Cambridge, MA 02139)

    1999-01-01

    A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically.

  8. Polyimide-coated embedded optical fiber sensors

    Science.gov (United States)

    Nath, Dilip K.; Nelson, Gary W.; Griffin, Stephen E.; Harrington, C. T.; He, Yi-Fei; Reinhart, Lawrence J.; Paine, D. C.; Morse, Theodore F.

    1991-10-01

    The present paper describes the behavior of embedded optical sensor fibers in a high- temperature PEEK (polyether ether ketone) carbon fiber composite. Sheets of this material, 200 micrometers thick, were layered in alternating directions for the carbon fibers. Typically, 16 sheets were used to form 3' X 6' or 3' X 8' panels by placing the optical fibers in the middle of the `prepreg' sheets, which were then heated to the processing temperature, and subjected to a pressure of 300 psi during the cool-down phase. Since the ordinary polymeric coatings of optical fibers cannot survive the 380 degree(s)C to 400 degree(s)C processing temperature of PEEK impregnated fiber composites, all of the optical sensor fibers tested were polyimide coated. The optical, mechanical, and thermal properties are reported and it is concluded that polyimide coated fibers can withstand PEEK processing conditions.

  9. Ball lens fiber optic sensor based smart handheld microsurgical instrument

    Science.gov (United States)

    Song, Cheol; Gehlbach, Peter L.; Kang, Jin U.

    2013-03-01

    During freehand performance of vitreoretinal microsurgery the surgeon must perform precise and stable maneuvers that achieve surgical objectives and avoid surgical risk. Here, we present an improved smart handheld microsurgical tool which is based on a ball lens fiber optic sensor that utilizes common path swept source optical coherence tomography. Improvements include incorporation of a ball lens single mode fiber optic probe that increases the working angle of the tool to greater than 45 degrees; and increases the magnitude of the distance sensing signal through water. Also presented is a cutting function with an improved ergonomic design.

  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. LDEF fiber optic exposure experiment

    International Nuclear Information System (INIS)

    Ten fiber optic cable samples of different types were exposed in low Earth orbit for over 5.5 years on the Long Duration Exposure Facility (LDEF). Four of the samples were mounted externally, and the remaining six were internal, under approximately .5 gc/sq m of aluminum. The experiment was recovered in January of 1990, and laboratory evaluation of the effects of the exposure has continued since. An increase in loss, presumed to be from radiation darkening, aging effects on polymer materials used in cabling, unique contamination effects on connector terminations, and micrometeoroid impacts were observed on some of the samples. In addition, the dependence of sample loss was measured as a function of temperature before and after the flight. All cable samples were functional, and the best exhibited no measurable change in performance, indicating that conventional fiber optic cables can perform satisfactorily in spacecraft. Experimental results obtained to date will be presented and discussed

  12. 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.

  13. Color centers in optic fibers

    International Nuclear Information System (INIS)

    Full text: Short-living and stationary color centers are studied in optic fibers (OF) with concentration of OH 1000 ppm at the temperatures of 77-300 K. As it was demonstrated in [1] concentration of OH of 1000 ppm in the optic fibers at room temperature does not observed. The studies showed that under irradiation at 77 K the color centers are formed with the absorption bands at 215, 260, 330 and 550 nm. In this work the idea was proposed that under irradiation with 105 Rad non-bridge oxygen atoms is not formed. This is supported by the researches showing that the band 215 nm, which is formed by E - centers, disappears at two values of temperature. The first E - centers disappear at 77 K, whereas the second one at 310 K. Here, the first E - center can be observed at 470-500 nm. Based on the stated above we assume that the values of OH concentration at 1000 ppm in optic fibers are not correct. It is obtained that at low temperatures of 77 - 300 K new phenomena are observed, i.e. existence of two E - color with peaks at 215 nm. The values of temperature at which these centers exist are different, the first exist at temperature up to 85 K, and the second one up to 300 K. (author) Reference: 1. V.B. Gavrilov, A.I. Golutvan, Yu.S. Gershtein et al. Absorption spectra in pure quartz optic fibers gamma-irradiated with 60Co source. // Instrumentation and techniques of experiment.- 1997.- No 4.- p. 23-32.

  14. Fiber optic accelerometers and seismometers

    Energy Technology Data Exchange (ETDEWEB)

    Brown, D.A. [Department of Electrical and Computer Engineering, University of Massachusetts Dartmouth, North Dartmouth, Massachusetts 02747 (United States)]|[Naval Postgraduate School, Monterey, California 93943 (United States)

    1996-04-01

    This paper presents performance and figures-of-merit of fiber optic interferometric accelerometers and seismometers using flexural disk, mandrel, and fluid filled transducers. Flexural disk devices having sensitivities of 50 radians/g and operating bandwidths to 2 kHz have been reported. This sensitivity corresponds to a minimum detectable signal of 20 nano-g/{radical}Hz for a system demodulation noise floor of 1 micro-radian/{radical}Hz. {copyright} {ital 1996 American Institute of Physics.}

  15. Brillouin optical time-domain analysis of fiber-optic parametric amplifiers

    OpenAIRE

    Vedadi, Armand; Alasia, Dario; Lantz, Eric; Maillotte, Herve?; The?venaz, Luc; Gonzalez-herraez, Miguel; Sylvestre, Thibaut

    2007-01-01

    We carried out distributed measurements of the longitudinal gain of fiber-optical parametric amplifiers using a novel sensing technique based on Brillouin optical time-domain analysis. Using this technique, we successfully characterized different gain behaviors in the linear and the saturation regimes. In addition, we demonstrated the recently predicted gain reciprocity at opposite ends of the amplifier span.

  16. 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

  17. A Polymer Optical Fiber Fuel Level Sensor: Application to Paramotoring and Powered Paragliding

    OpenAIRE

    David Sánchez Montero; Carmen Vázquez; Pedro Contreras Lallana

    2012-01-01

    A low-cost intensity-based polymer optical fiber (POF) sensor for fuel level measurements in paramotoring and powered paragliding is presented, exploiting the advantages of the optical fiber sensing technology. Experimental results demonstrate that the best option can be performed by stripping the fiber at the desired discrete points to measure the fuel level as well as with a gauge-shape fiber bending. The prototype has a good linearity, better than 4% full scale (F.S.), and sensitivity arou...

  18. Preliminary Development of a Fiber Optic Sensor for Measuring Bilirubin

    OpenAIRE

    Babin, Steven M.; Raymond M. Sova

    2014-01-01

    Preliminary development of a fiber optic bilirubin sensor is described, where an unclad sensing portion is used to provide evanescent wave interaction of the transmitted light with the chemical environment. By using a wavelength corresponding to a bilirubin absorption peak, the Beer–Lambert Law can be used to relate the concentration of bilirubin surrounding the sensing portion to the amount of absorbed light. Initial testing in vitro suggests that the sensor response is consistent with the...

  19. Qualification of a truly distributed fiber optic technique for strain and temperature measurements in concrete structures

    OpenAIRE

    Taillade F.; Bertand J.; Delepine-Lesoille S.; Moreau G.; Salin J.; Henault J.M.; Quiertant M.; Benzarti K.

    2010-01-01

    Structural health monitoring is a key factor in life cycle management of infrastructures. Truly distributed fiber optic sensors are able to provide relevant information on large structures, such as nuclear power plants or nuclear waste disposal facilities. The sensing chain includes an optoelectronic unit and a sensing cable made of one or more optical fibers. A new instrument based on Optical Frequency Domain Reflectometry (OFDR), enables to perform temperature and strain measurements with a...

  20. On-fiber plasmonic interferometer for multi-parameter sensing.

    Science.gov (United States)

    Zhang, Zhijian; Chen, Yongyao; Liu, Haijun; Bae, Hyungdae; Olson, Douglas A; Gupta, Ashwani K; Yu, Miao

    2015-04-20

    We demonstrate a novel miniature multi-parameter sensing device based on a plasmonic interferometer fabricated on a fiber facet in the optical communication wavelength range. This device enables the coupling between surface plasmon resonance and plasmonic interference in the structure, which are the two essential mechanisms for multi-parameter sensing. We experimentally show that these two mechanisms have distinctive responses to temperature and refractive index, rendering the device the capability of simultaneous temperature and refractive index measurement on an ultra-miniature form factor. A high refractive index sensitivity of 220 nm per refractive index unit (RIU) and a high temperature sensitivity of -60 pm/ °C is achieved with our device. PMID:25969110

  1. A Fiber-Tip Label-Free Biological Sensing Platform: A Practical Approach toward In-Vivo Sensing

    Directory of Open Access Journals (Sweden)

    Alexandre François

    2015-01-01

    Full Text Available The platform presented here was devised to address the unmet need for real time label-free in vivo sensing by bringing together a refractive index transduction mechanism based on Whispering Gallery Modes (WGM in dye doped microspheres and Microstructured Optical Fibers. In addition to providing remote excitation and collection of the WGM signal, the fiber provides significant practical advantages such as an easy manipulation of the microresonator and the use of this sensor in a dip sensing architecture, alleviating the need for a complex microfluidic interface. Here, we present the first demonstration of the use of this approach for biological sensing and evaluate its limitation in a sensing configuration deprived of liquid flow which is most likely to occur in an in vivo setting. We also demonstrate the ability of this sensing platform to be operated above its lasing threshold, enabling enhanced device performance.

  2. Air backed mandrel type fiber optic hydrophone with low noise floor

    Science.gov (United States)

    Rajesh, R.; V, Sreehari C.; N, Praveen Kumar; Awasthi, R. L.; K, Vivek; B, Vishnu M.; Santhanakrishnan, T.; Moosad, K. P. B.; Mathew, Basil

    2014-10-01

    Low noise fiber optic hydrophone based on optical fiber coil wound on air-backed mandrel was developed. The sensor can be effectively used for underwater acoustic sensing. The design and characterization of the hydrophone is illustrated in this paper. A fiber Mach-Zehnder Interferometer (MZI) was developed and coupled with a Distributed Feedback (DFB) fiber laser source and an optical phase demodulation system, with an active modulation in one of the arms. The sensor head design was optimized to achieve noise spectral density <10 ?rad/?Hz, for yielding sufficient sensitivity to sense acoustic pressure close to Deep Sea Sate Zero (DSS0).

  3. 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.

  4. Interferometric microstructured polymer optical fiber ultrasound sensor for optoacoustic endoscopic imaging in biomedical applications

    Science.gov (United States)

    Gallego, Daniel; Sáez-Rodríguez, David; Webb, David; Bang, Ole; Lamela, Horacio

    2014-05-01

    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.

  5. Interference effects in optical fiber connections.

    Science.gov (United States)

    Wagner, R E; Sandahl, C R

    1982-04-15

    Optical interference may occur in fiber connections, and this can have an important effect on transmission loss. A theoretical analysis shows that the effect occurs in both single-mode and multimode fibers and depends on fiber end face separation, the source spectrum, and the modal power distribution in the fiber. Experimental observations of interference in dry multimode fiber connections confirm the analysis for both laser diode and LED sources. PMID:20389863

  6. Reliability Considerations In Fiber Optic System Design

    Science.gov (United States)

    Paul, D. K.

    1987-02-01

    This paper summarizes the state-of-the-art operational and reliability characteristics of fiber optical components typical of those used in optical transmission systems. Standby requirements for vulnerable components are evaluated by using this data in relevant reliability formulae developed for fiber optic systems having a redundant design.

  7. Study on a fiber optic gradient hydrophone based on interferometer

    Science.gov (United States)

    Lv, Wenlei; Pang, Meng; Shi, Qingping; Zhang, Min; Liao, Yanbiao; Yuan, Libo; Kang, Chong

    2008-12-01

    We proposed a kind of fiber-optic gradient hydrophone based on interferometer. Two arms of the interferometer are sensing fibers, each of which can be regard as a scalar pressure sensing element, and then the phase gradient between the two elements is transformed into the light intensity modulated output by the coupler. In this paper, a suit of analytical models for researching the sensor performance are developed. The theoretical and experimental research was carried out to demonstrate this kind of gradient hydrophone's phase sensitivity as the function of the measure frequency and the "8" directivity response.

  8. 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...

  9. Use of Distributed Fiber Optic Sensors to Detect Damage in a Pavement

    OpenAIRE

    Chapeleau, Xavier; BLANC, Juliette; Hornych, Pierre; Gautier, Jean-Luc; Carroget, Jean

    2014-01-01

    This paper presents the feasibility of damage detection in the asphalt pavements by embedded fiber optics as a new non-destructive inspection technique. The distributed fiber optic sensing technology called ÒRayleigh techniqueî was used in this study. The main advantage of this technique is that it allows to measure strains over long length of fiber optic with a high spatial resolution, less than 1 cm. By comparing strain profiles measured at different time, an attempt was made to link strain...

  10. Brillouin Corrosion Expansion Sensors for Steel Reinforced Concrete Structures Using a Fiber Optic Coil Winding Method

    OpenAIRE

    Xingjun Lv; Jinping Ou; Jie Lu(IFIC, Universitat de València – CSIC, Apt. Correus 22085, E-46071 València, Spain); 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. ...

  11. Optical fiber gas sensor development and application

    Science.gov (United States)

    Jin, W.; Ho, H. L.

    2008-12-01

    This paper reports recent development and application of optical fiber gas sensors using absorption spectroscopy, including open-path gas sensors using fiber coupled micro-optic cells and photonic bandgap (PBG) fibers. A fiber-optic sensor system capable of detecting dissolved fault gases in oil-insulated equipment in power industry is presented. The gases include methane (CH4), acetylene (C2H2) and ethylene (C2H4). In addition, the development of gas sensor using PBG fiber will be reported.

  12. 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.

  13. Interfacial characterization of soil-embedded optical fiber for ground deformation measurement

    Science.gov (United States)

    Zhang, Cheng-Cheng; Zhu, Hong-Hu; Shi, Bin; She, Jun-Kuan

    2014-09-01

    Recently fiber-optic sensing technologies have been applied for performance monitoring of geotechnical structures such as slopes, foundations, and retaining walls. However, the validity of measured data from soil-embedded optical fibers is strongly influenced by the properties of the interface between the sensing fiber and the soil mass. This paper presents a study of the interfacial properties of an optical fiber embedded in soil with an emphasis on the effect of overburden pressure. Laboratory pullout tests were conducted to investigate the load-deformation characteristics of a 0.9 mm tight-buffered optical fiber embedded in soil. Based on a tri-linear interfacial shear stress-displacement relationship, an analytical model was derived to describe the progressive pullout behavior of an optical fiber from soil matrix. A comparison between the experimental and predicted results verified the effectiveness of the proposed pullout model. The test results are further interpreted and discussed. It is found that the interfacial bond between an optical fiber and soil is prominently enhanced under high overburden pressures. The apparent coefficients of friction of the optical fiber/soil interface decrease as the overburden pressure increases, due to the restrained soil dilation around the optical fiber. Furthermore, to facilitate the analysis of strain measurement, three working states of a soil-embedded sensing fiber were defined in terms of two characteristic displacements.

  14. 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...

  15. Fiber-optical accelerometers based on polymer optical fiber Bragg gratings

    OpenAIRE

    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.

  16. General purpose fiber optic hydrophone made of castable epoxy

    Science.gov (United States)

    Garrett, Steven L.; Brown, David A.; Beaton, Brian L.; Wetterskog, Kevin; Serocki, John

    1991-02-01

    A fiber-optic, interferometric, flexural disk hydrophone cast from an epoxy resin is described. This hydrophone is designed in the shape of an enclosed, hollow cylinder with pairs of flat, spiral wound coils of optical fiber embedded in each sensing plate. An all-fiber Michelson interferometer is used to detect the optical phase shift which results from pressure induced strains in the optical fiber. The sensing coils are positioned in the plates in a manner to enhance the acoustic response and provide cancelation of acceleration induced signals. An epoxy resin was chosen for its relatively high tensile strength, its low Young's modulus, and its ability to cure at room temperature. The acoustic sensitivity of this sensor in both air and water was measured to be 0.277 0.005 rad/Pa (-131.2 dB re rad/?Pa) which corresponds to a normalized sensitivity (formula available in paper)re 1 ?Pa-1 below 1 .0 kHz. This measured result is in excellent agreement with simple elastic theory and the measured epoxy elastic constants. The normalized acceleration sensitivity is (formula available in paper)dB re g-1. The acceleration-to-acoustic sensitivity ratio (figure-of-merit) of -134 dB re g4tPa is the largest reported to date for any fiber-optic hydrophone.

  17. Large-scale multiplexed fiber optic arrays for geophysical applications

    Science.gov (United States)

    Nash, Phillip J.; Cranch, Geoffrey A.; Hill, David J.

    2000-12-01

    Fiber optic sensors are becoming a well-established technology for a range of geophysical applications, and static pressure and temperature sensors in particular are now comparatively well developed. However, rather less attention has been paid to systems for measuring dynamic quantities such as acoustic and seismic signals. Furthermore, the very large multiplexing potential of fiber optic sensing systems has yet to be fully explored for geophysical applications. However, development of fiber optic sonar systems for military applications has proven the viability of large multiplexed arrays, and demonstrated advantages which include electrically passive arrays, long term reliability and the potential for operation in very deep ($GTR3000m) water. This paper describes the applications for large scale fiber optic sensing arrays in geophysical metrology. The main applications considered here are ocean bottom cables and streamers for marine seismic, and downwell seismic systems. Systems can require up to several thousand channels and the use of multi- component sensors, which include 3-axis geophones and hydrophones. The paper discusses the specific requirements for each application, and shows how these requirements can be met using a system approach based on time and wavelength multiplexing of interferometric sensors. Experimental and theoretical studies at DERA into the performance of highly multiplexed systems are also described, together with initial development work on fiber optic hydrophones and geophones.

  18. An update on monitoring moisture ingression with fiber optic sensors

    Science.gov (United States)

    Trego, Angela

    2003-11-01

    Newly developed advanced aircraft structures are utilizing composite technology for improving stiffness, strength and weight properties. Such structures are commonly found in inaccessible regions where current NDE techniques are limited. The development of low profile, distributed, embeddable, real-time, optical fiber sensors capable of detecting the onset of composite failure in aircraft structures would eliminate a significant portion of related maintenance costs. Notable composite failures that are difficult to assess include delaminations and moisture ingression issues. Optical fiber-based sensors add the inherent advantages of being lightweight, low profile, immune to EMI, resistant to harsh environments, and highly sensitive to a variety of physical and chemical measurements. Optical fiber-based sensors can also be embedded directly into the composite part during manufacturing and co-cured. This creates a monitoring system that has little impact on the properties of the final part while providing significant benefits. Fiber optics embedded in composite honeycomb panels were fabricated and tested using ground - air - ground thermal cycles to determine moisture ingression monitoring capabilities of the sensors. Two different types of moisture sensing fiber optics were measured. One type of installed moisture sensor is based off of a Bragg grating system, while the other moisture sensor is based off of a long period grating system. Presented herein is a comparison of the two different types of fiber optic sensors that monitored the moisture ingression in honeycomb panels.

  19. 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...

  20. 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)

  1. Degradation points detection in optical fiber

    Science.gov (United States)

    Salikhov, Aydar I.

    2015-03-01

    In this paper, we propose a new algorithm for monitoring the state of the fiber-optic link using polarization effects. The necessity of this work is because currently in operation is a very large number of fiber-optic cables with expired or expiring operation. This means that they are actively developing microcracks and other local defects. In this paper we propose a method for continuous monitoring of optical fiber communication cables.

  2. 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

  3. 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.

  4. 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

    Science.gov (United States)

    Hassan, Moinuddin; Ilev, Ilko

    2014-10-01

    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.

  5. 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.

  6. Flexible Optical Waveguide Bent Loss Attenuation Effects Analysis and Modeling Application to an Intrinsic Optical Fiber Temperature Sensor

    OpenAIRE

    Patrick Meyrueis; Francis Georges; Mustapha Remouche

    2012-01-01

    The temperature dependence of the bending loss light energy in multimode optical fibers is reported and analyzed. The work described in this paper aims to extend an initial previous analysis concerning planar optical waveguides, light energy loss, to circular optical waveguides. The paper also presents à novel intrinsic fiber optic sensing device base on this study allowing to measure temperatures parameters. The simulation results are validated theoretically in the case of silica/silicone o...

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Fiber-optic based instrumentation for water and air monitoring

    International Nuclear Information System (INIS)

    In this paper real-time in-situ water and air monitoring capabilities based on fiber-optic sensing technology are described. This relatively new technology combines advances in fiber optic and optoelectronics with chemical spectorscopic techniques to enable field environmental monitoring of sub ppm quantities of specific pollutants. The advantages of this technology over conventional sampling methods are outlined. As it is the more developed area the emphasis is on water quality monitoring rather than air. Examples of commercially available, soon-to be available and laboratory systems are presented. One such example is a system used to detect hydrocarbon spills and leaking of underground hydrocarbon storage tanks

  12. A fiber optics textile composite sensor for geotechnical applications

    Science.gov (United States)

    Artières, Olivier; Dortland, Gerrit

    2010-09-01

    The fiber optics in structural health monitoring systems for civil engineering applications have been widely used. By integrating fiber optic sensing into a geotextile fabric, the TenCate GeoDetect® system is the first designed specifically for geotechnical applications. This monitoring solution embodies fiber optics on a geotextile fabric, e.g. a textile used into the soil, and combines the benefits of geotextile materials, such as high interface friction in contact with the soil, with the latest fiber optics sensing technologies. It aims to monitor geotechnical structure and to generate early warnings if it detects and localizes the early signs of malfunctioning, such as leaks or instability. This is a customizable solution: Fiber Bragg gratings, Brillouin and Raman scattering can be built into this system. These technologies measure both strain and temperature changes in soil structures. It can provide a leak and deformation location within accuracies resp. 1 l/min/m and 0.02%. The TenCate GeoDetect® solution provides objective, highly precise, and timely in-situ performance information, allowing the design professional and owner to understand system performance in addition to providing alerts for negative "geo-events" (subsidence) and other potentially deleterious events.

  13. A cylindrical-core fiber-optic oxygen sensor based on fluorescence quenching of a platinum complex immobilized in a polymer matrix

    OpenAIRE

    Chen, R.; Farmery, AD; Obeid, A; Hahn, CEW

    2012-01-01

    A miniature (200 ?m in diameter) cylindrical-core fiber-optic oxygen sensor has been developed for measuring rapid change in oxygen partial pressure (pO 2). The fiber-optic sensing element is based on a cylindrical-core waveguide structure formed by coating a thin medical grade polymer sensing film that contains immobilized Pt(II) complexes on silica optical fiber. The performance such as sensitivity and time response of the fiber-optic oxygen sensors were evaluated...

  14. 21 CFR 872.4620 - Fiber optic dental light.

    Science.gov (United States)

    2010-04-01

    ...2010-04-01 2010-04-01 false Fiber optic dental light. 872.4620 Section 872... Surgical Devices § 872.4620 Fiber optic dental light. (a) Identification. A fiber optic dental light is a device that is a...

  15. 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

  16. 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.

  17. Measuring Bragg gratings in multimode optical fibers.

    Science.gov (United States)

    Schmid, Markus J; Müller, Mathias S

    2015-03-23

    Fiber Bragg gratings (FBG) in multimode optical fibers provide a means for cost-effictive devices resulting in simplified and robust optic sensor systems. Parasitic mode effects in optical components of the entire measurement system strongly influence the measured multi-resonance reflection spectrum. Using a mode transfer matrix formalism we can describe these complex mode coupling effects in multimode optical systems in more detail. We demonstrate the accordance of the theory by two experiments. With this formalism it is possible to understand and optimize mode effects in multimode fiber optic systems. PMID:25837146

  18. 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

  19. Fiber optic gyroscope using an eight-component LiNbO3 integrated optic circuit

    Science.gov (United States)

    Minford, W. J.; Stone, F. T.; Youmans, B. R.; Bartman, R. K.

    1990-01-01

    A LiNbO3 integrated optic circuit (IOC) containing eight optical functions has been successfully incorporated into an interferometric fiber optic gyroscope. The IOC has the minimum configuration optical functions (a phase modulator, a polarizer, and two beam splitters) and Jet Propulsion Laboratory's novel beat detection circuit (a phase modulator, two optical taps, and a beam splitter) which provides a means of directly reading angular position and rotation rate. The optical subsystem consisting of the fiber-pigtailed IOC and a sensing coil of 945 meters of polarization-maintaining fiber has a loss of 18.7dB, which includes 9dB due to the architecture and unpolarized source. A random walk coefficient was measured using an edge-emitting LED as the source.

  20. 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

  1. 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.

  2. 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.

  3. Fiber Optic Microswitch For Industrial Use

    Science.gov (United States)

    Desforges, F. X.; Jeunhomme, L. B.; Graindorge, Ph.; LeBoudec, G.

    1988-03-01

    Process control instrumentation is a large potential market for fiber optic sensors and particulary for fiber optic microswitches. Use of such devices brings a lot of advantages such as lighter cables, E.M. immunity, intrinsic security due to optical measurement, no grounding problems and so on. However, commercially available fiber optic microswitches exhibit high insertion losses as well as non optimal mechanical design. In fact, these drawbacks are due to operation principles which are based on a mobile shutter displaced between two fibers. The fiber optic microswitch we present here, has been specially designed for harsh environments (oil industry). The patented operation principle uses only one fiber placed in front of a retroreflecting material by the mean of a fiber optic connector. The use of this retroreflector material allows an important reduction of the position tolerances required in two fibers devices, as well as easier fabrication and potential mass production of the optical microswitch. Moreover, such a configuration yields good performances in term of reflection coefficient leading to large dynamic range and consequently large distances (up to 250 m) between the optical microswitch and its optoelectronic instrument. Optomechanical design of the microswitch as well as electronic design of the optoelectronic instrument will be examined and discussed.

  4. FOA Lecture 20: Other Fiber Optic Tests

    Science.gov (United States)

    This is Lecture 20 in the Fiber Optic Association's series on fiber optics. This video covers some lesser well-known tests like reflectance, CD and PMD that are important to long distance and high speed links. Running time for the lecture is 7:52. Flash is required to view the video.

  5. 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

  6. Miniaturized mandrel-based fiber optic hydrophone.

    Science.gov (United States)

    Ames, Gregory H; Maguire, Jason M

    2007-03-01

    Fiber optic hydrophones typically use a long sensor fiber wrapped around an air-filled mandrel to achieve high responsivity. Minimum mandrel diameter is determined by fiber reliability considerations. A miniature hydrophone, with diameter of about a third that of previous hydrophones, is reported. Such a hydrophone has applications for very thin towed arrays. Small diameter fiber with high strength Bragg gratings written through the coating are key enablers. PMID:17407875

  7. FOA Lecture 12: Fiber Optic Testing Overview

    Science.gov (United States)

    Lecture 12 begins a series of lectures on fiber optic testing. In this lecture, the presenter discusses what fiber optic testing means- what components need testing and where testing is done. The next few lectures will cover topics like visual testing, insertion loss, OTDR testing and advanced topics like testing multimode and singlemode fibers and long haul link testing. Those lectures are available separately. Running time for the lecture is 9:35. Flash is required to view the video.

  8. Fiber Optic Temperature Sensors for Thermal Protection Systems Project

    National Aeronautics and Space Administration — Intelligent Fiber Optic Systems Corporation (IFOS) proposes an innovative fiber optic-based, multiplexable, highly ruggedized, integrated sensor system for...

  9. A polymer optical fiber fuel level sensor: application to paramotoring and powered paragliding.

    Science.gov (United States)

    Sánchez Montero, David; Contreras Lallana, Pedro; Vázquez, Carmen

    2012-01-01

    A low-cost intensity-based polymer optical fiber (POF) sensor for fuel level measurements in paramotoring and powered paragliding is presented, exploiting the advantages of the optical fiber sensing technology. Experimental results demonstrate that the best option can be performed by stripping the fiber at the desired discrete points to measure the fuel level as well as with a gauge-shape fiber bending. The prototype has a good linearity, better than 4% full scale (F.S.), and sensitivity around 0.5 V per bend are obtained. Hysteresis due to residual fluid at the sensing points is found to be less than 9% F.S. PMID:22778637

  10. A Polymer Optical Fiber Fuel Level Sensor: Application to Paramotoring and Powered Paragliding

    Directory of Open Access Journals (Sweden)

    David Sánchez Montero

    2012-05-01

    Full Text Available A low-cost intensity-based polymer optical fiber (POF sensor for fuel level measurements in paramotoring and powered paragliding is presented, exploiting the advantages of the optical fiber sensing technology. Experimental results demonstrate that the best option can be performed by stripping the fiber at the desired discrete points to measure the fuel level as well as with a gauge-shape fiber bending. The prototype has a good linearity, better than 4% full scale (F.S., and sensitivity around 0.5 V per bend are obtained. Hysteresis due to residual fluid at the sensing points is found to be less than 9% F.S.

  11. Fiber optic applications in nuclear power plants

    International Nuclear Information System (INIS)

    Fiber optic technology possesses many desirable attributes for applications in commercial nuclear power plants. The non-electrical nature of fiber optics is an important factor in an industry governed by federal safety regulations such as Class 1E isolation and separation criteria. Immunity from Electromagnetic Interference (EMI), an increasing industry problem area, is another significant characteristic. Because of the extremely wide bandwidth offered, fiber optics better addresses the data acquisition and communication requirements of the complex processes of a nuclear power plant. Potential for fiber optic sensor applications exists within the nuclear industry because their small size and physical flexibility allows access into normally inaccessible areas. They possess high accuracy and allow environmentally sensitive electronics to be remotely located. The purpose of this paper is to explore current applications for fiber optic technology in modern nuclear plants, document examples of present day usage in C-E plants and suggest possible future application areas

  12. Fiber optic applications in nuclear power plants

    International Nuclear Information System (INIS)

    Fiber optic technology possesses many desirable attributes for applications in commercial nuclear power plants. The non-electrical nature of fiber optics is an important factor in an industry governed by federal safety regulations such as Class 1E isolation and separation criteria. Immunity from Electromagnetic Interference (EMI), an increasing industry problem area, is another significant characteristic. Because of the extremely wide bandwidth offered, fiber optics better addresses the data acquistion and communication requirements of the complex processes of a nuclear power plant. Potential for fiber optic sensor applications exists within the nuclear industry because their small size and physical flexibility allows access into normally inaccessible areas. They possess high accuracy and allow environmentally sensitive electronics to be remotely located. The purpose of this paper is to explore current applications for fiber optic technology in modern nuclear plants, document examples of present day usage in C-E plants and suggest possible future application areas

  13. A Large Area Fiber Optic Gyroscope on multiplexed fiber network

    OpenAIRE

    Pizzocaro, Marco; Costanzo, Giovanni Antonio; Clivati, Cecilia

    2013-01-01

    We describe a fiber optical gyroscope based on the Sagnac effect realized on a multiplexed telecom fiber network. Our loop encloses an area of 20 km^2 and coexists with Internet data traffic. This Sagnac interferometer achieves a sensitivity of about 1e-8 (rad/s)/sqrt(Hz), thus approaching ring laser gyroscopes without using narrow-linewidth laser nor sophisticated optics. The proposed gyroscope is sensitive enough for seismic applications, opening new possibilities for this...

  14. Optical fiber sensor having an active core

    Science.gov (United States)

    Egalon, Claudio Oliveira (inventor); Rogowski, Robert S. (inventor)

    1993-01-01

    An optical fiber is provided. The fiber is comprised of an active fiber core which produces waves of light upon excitation. A factor ka is identified and increased until a desired improvement in power efficiency is obtained. The variable a is the radius of the active fiber core and k is defined as 2 pi/lambda wherein lambda is the wavelength of the light produced by the active fiber core. In one embodiment, the factor ka is increased until the power efficiency stabilizes. In addition to a bare fiber core embodiment, a two-stage fluorescent fiber is provided wherein an active cladding surrounds a portion of the active fiber core having an improved ka factor. The power efficiency of the embodiment is further improved by increasing a difference between the respective indices of refraction of the active cladding and the active fiber core.

  15. Internally sensed optical phased array.

    Science.gov (United States)

    Bowman, David J; King, Malcolm J; Sutton, Andrew J; Wuchenich, Danielle M; Ward, Robert L; Malikides, Emmanuel A; McClelland, David E; Shaddock, Daniel A

    2013-04-01

    Extending phased array techniques to optical frequencies is challenging because of the considerably smaller wavelengths and the difficulty of stabilizing the optical path lengths of multiple emitters to this level of precision. This is especially true under real-world conditions where thermal and vibrational disturbances cause path length variations that are considerable in relation to the wavelength. Earlier attempts have relied on an external mechanism to sense and compensate for any unwanted variations in the outgoing beams. Here we propose and demonstrate a method that does not rely on any external components. The method combines a pseudo-random noise phase modulation scheme together with conventional heterodyne interferometry to simultaneously measure phase variations between emitters. This information is then used to control the relative phases between the emitters and compensate for any unwanted disturbance. Experimental results are presented that support the viability of this design. PMID:23546269

  16. Harsh environment fiber optic connectors/testing

    Science.gov (United States)

    Parker, Douglas A.

    2014-09-01

    Fiber optic systems are used frequently in military, aerospace and commercial aviation programs. There is a long history of implementing fiber optic data transfer for aircraft control, for harsh environment use in local area networks and more recently for in-flight entertainment systems. The advantages of fiber optics include high data rate capacity, low weight, immunity to EMI/RFI, and security from signal tapping. Technicians must be trained particularly to install and maintain fiber systems, but it is not necessarily more difficult than wire systems. However, the testing of the fiber optic interconnection system must be conducted in a standardized manner to assure proper performance. Testing can be conducted with slight differences in the set-up and procedure that produce significantly different test results. This paper reviews various options of interconnect configurations and discusses how these options can affect the performance, maintenance required and longevity of a fiber optic system, depending on the environment. Proper test methods are discussed. There is a review of the essentials of proper fiber optic testing and impact of changing such test parameters as input launch conditions, wavelength considerations, power meter options and the basic methods of testing. This becomes important right from the start when the supplier test data differs from the user's data check upon receiving the product. It also is important in periodic testing. Properly conducting the fiber optic testing will eliminate confusion and produce meaningful test results for a given harsh environment application.

  17. Fiber optic cryogenic liquid level detection system for space applications

    Science.gov (United States)

    Kazemi, Alex A.; Yang, Chengning; Chen, Shiping

    2009-05-01

    Liquid hydrogen and oxygen are widely used as fuels in space vehicles. Because both are highly dangerous materials prone to explosion, detection of the liquid level in fuel tank becomes a critical element for the safety and efficiency in space operations. Two liquid level sensing techniques are presented in this paper. The first technique is based on optical fiber long period gratings. In this technique, the full length of a specially fabricated fiber is the body of the probe becomes the length of the sensing fiber that is submerged in the liquid can be detected by the interrogation system. The second system uses optical fibers to guide light to and from an array of point probes. These probes are specially fabricated, miniature optical components which reflects a substantial amount of light back into the lead fiber when the probe is gas but almost no light when it is in liquid. A detailed theoretical study by computer simulation was carried out on these two techniques in order to determine which technique was more suitable for experimental investigation. The study revealed that although the first technique may provide more potential benefits in terms of weight and easy installation; a number of technical challenges make it not suitable for a short term solution. The second, probe array based technique, on the other hand, is more mature technically. The rest of the research program was therefore focused on the experimental investigation of the probe array detection technique and the test results are presented in this paper.

  18. Fiber optic liquid level sensor system for aerospace applications

    Science.gov (United States)

    Kazemi, Alex A.; Yang, Chenging; Chen, Shiping

    2014-09-01

    Detection of the liquid level in fuel tank becomes a critical element for the safety and efficiency in aerospace operations. Two liquid level sensing techniques are presented in this paper. The first technique is based on optical fiber Long Period Gratings (LPG). In this system, the full length of a specially fabricated fiber is the body of the probe because the length of the sensing fiber that is submerged in the liquid can be detected by the interrogation system. The second system based on Total Internal Reflection (TIR) uses optical fibers to guide light to and from an array of point probes. These probes are specially fabricated, miniature optical components which reflects a substantial amount of light back into the lead fiber when the probe is gas but almost no light when it is in liquid. A detailed theoretical study by computer simulation was carried out on these two techniques in order to determine which technique was more suitable for experimental investigation. The study revealed that although the first technique may provide more potential benefits in terms of weight and easy installation; a number of technical challenges make it not suitable for a short term solution. The second, probe array based technique, on the other hand, is more mature technically. The rest of the research program was therefore focused on the experimental investigation of the probe array detection technique and the test results are presented in this paper.

  19. Optical gas sensing responses in transparent conducting oxides with large free carrier density

    Science.gov (United States)

    Ohodnicki, P. R.; Andio, M.; Wang, C.

    2014-07-01

    Inherent advantages of optical-based sensing devices motivate a need for materials with useful optical responses that can be utilized as thin film functional sensor layers. Transparent conducting metal oxides with large electrical conductivities as typified by Al-doped ZnO (AZO) display attractive properties for high temperature optical gas sensing through strong optical transduction of responses conventionally monitored through changes in measured electrical resistivity. An enhanced optical sensing response in the near-infrared and ultraviolet/visible wavelength ranges is demonstrated experimentally and linked with characteristic modifications to the dielectric constant due to a relatively high concentration of free charge carriers. The impact of light scattering on the magnitude and wavelength dependence of the sensing response is also discussed highlighting the potential for tuning the optical sensing response by controlling the surface roughness of a continuous film or the average particle size of a nanoparticle-based film. The physics underpinning the optical sensing response for AZO films on planar substrates yields significant insight into the measured sensing response for optical fiber-based evanescent wave absorption spectroscopy sensors employing an AZO sensing layer. The physics of optical gas sensing discussed here provides a pathway towards development of sensing materials for extreme temperature optical gas sensing applications. As one example, preliminary results are presented for a Nb-doped TiO2 film with sufficient stability and relatively large sensing responses at sensing temperatures greater than 500 °C.

  20. Fiber-Optic Interferometry Using Narrowband Light Source and Electrical Spectrum Analyzer: Influence on Brillouin Measurement

    OpenAIRE

    Mizuno, Yosuke; Hayashi, Neisei; Nakamura, Kentaro

    2014-01-01

    We observe an interference pattern using a simple fiber-optic interferometer consisting of an electrical spectrum analyzer and a narrowband light source, which is commonly employed for observing the Brillouin gain spectrum. This interference pattern expands well beyond the frequency range corresponding to the Brillouin frequency shift in silica fibers (approximately 11 GHz at 1550 nm). Using both silica single-mode and polymer optical sensing fibers, we then experimentally p...

  1. Low-cost fiber-optic chemochromic hydrogen detector

    Energy Technology Data Exchange (ETDEWEB)

    Benson, D.K.; Tracy, C.E.; Hishmeh, G.; Ciszek, P.; Lee, S.H. [National Renewable Energy Lab., Golden, CO (United States)

    1998-08-01

    The ability to detect hydrogen gas leaks economically and with inherent safety is an important technology that could facilitate commercial acceptance of hydrogen fuel in various applications. In particular, hydrogen fueled passenger vehicles will require hydrogen leak detectors to signal the activation of safety devices such as shutoff valves, ventilating fans, alarms, etc. Such detectors may be required in several locations within a vehicle--wherever a leak could pose a safety hazard. It is therefore important that the detectors be very economical. This paper reports progress on the development of low-cost fiber-optic hydrogen detectors intended to meet the needs of a hydrogen-fueled passenger vehicle. In the design, the presence of hydrogen in air is sensed by a thin-film coating at the end of a polymer optical fiber. When the coating reacts reversibly with the hydrogen, its optical properties are changed. Light from a central electro-optic control unit is projected down the optical fiber where it is reflected from the sensor coating back to central optical detectors. A change in the reflected intensity indicates the presence of hydrogen. The fiber-optic detector offers inherent safety by removing all electrical power from the leak sites and offers reduced signal processing problems by minimizing electromagnetic interference. Critical detector performance requirements include high selectivity, response speed and durability as well as potential for low-cost production.

  2. Fiber optic evanescent field sensors for pH monitoring in civil infrastructure

    Science.gov (United States)

    Ghandehari, Masoud; Vimer, Cristian S.

    2002-06-01

    Fiber optic pH sensors based on the evanescent field spectroscopic technique is studied. Portions of poly (-methyl methacrylate) (PMMA) cladding of plastic clad silica (PCS) optical fibers are replaced with new cladding composed of PMMA doped with a pH sensitive chromophore. Methyl Red, Thymol Blue, Thymolphtalein are used for sensing pH at the acid, neutral and base levels. Changes in the pH of the analyte are detected by measuring the absorption spectrum of the new cladding in the sensing region of the optical fiber.

  3. First observation of fiber fuse phenomenon in polymer optical fibers

    Science.gov (United States)

    Mizuno, Yosuke; Hayashi, Neisei; Tanaka, Hiroki; Nakamura, Kentaro; Todoroki, Shin-ichi

    2014-05-01

    Recently, distributed strain/temperature measurement based on Brillouin scattering in polymer optical fibers (POFs) has been successfully demonstrated, but its signal-to-noise ratio is not yet sufficient. One approach to overcome this issue is to enhance the incident optical power, which could cause a so-called fiber fuse phenomenon. In this study, we report the first observation of the fiber fuse in POFs. A fuse propagation velocity of 21.9 mm/s, which is 1-2 orders of magnitude slower than that in standard silica fibers, is experimentally demonstrated. The achieved threshold power density and proportionality constant between the propagation velocity and the power density are 1/180 of and 17 times the values for silica fibers, respectively. An oscillatory continuous curve instead of periodic voids is formed after the passage of the fuse. An easy fuse termination method is also presented.

  4. 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.

  5. Expansion of Dynamic Range in Interferometric Fiber Optic Hydrophone

    Science.gov (United States)

    Sato, Ryotaku; Saito, Shigemi

    2013-01-01

    In a conventional interferometric fiber optic hydrophone where a light pulse stops being generated before the last pulse finishes passing through a sensing fiber, the dynamic range cannot be expanded even if the sensing fiber is made long to enhance sensitivity. The reason is that a long repetition period of the light pulse causes a failure in demodulation of a high-level signal with a quick phase change. In this paper, the dynamic range is expanded at least by 26 dB by shortening the repetition period such that the pulses interfering with each other are avoided. The effect of a wide dynamic range is also confirmed by observing that when a high-level sound simulating a jamming sound is applied, a sound 95 dB lower than the jamming sound can be detected with the newly developed hydrophone.

  6. Optical fiber probe for all-optical photoacoustic measurement

    Science.gov (United States)

    Miida, Y.; Matsuura, Y.

    2013-03-01

    An optical fiber ultrasound probe for all-optical photoacoustic endoscopy imaging is developed. The probe has a Fabry Perot interferometer consisting of a polymer film attached at the end surface of a single-mode optical fiber. The interferometer detects acoustically-induced pressure change in the optical thickness and transforms the change into output optical power. Experimental results show that the probe functions well as a photoacoustic probe and the SNR is comparable to that of a PVDF hydrophone. Results for B-mode imaging of blood vessel phantom taken by using the fiber probe are also shown.

  7. Fiber Optic Sensors for Detection of Toxic and Biological Threats

    Science.gov (United States)

    El-Sherif, Mahmoud; Bansal, Lalitkumar; Yuan, Jianming

    2007-01-01

    Protection of public and military personnel from chemical and biological warfare agents is an urgent and growing national security need. Along with this idea, we have developed a novel class of fiber optic chemical sensors, for detection of toxic and biological materials. The design of these fiber optic sensors is based on a cladding modification approach. The original passive cladding of the fiber, in a small section, was removed and the fiber core was coated with a chemical sensitive material. Any change in the optical properties of the modified cladding material, due to the presence of a specific chemical vapor, changes the transmission properties of the fiber and result in modal power redistribution in multimode fibers. Both total intensity and modal power distribution (MPD) measurements were used to detect the output power change through the sensing fibers. The MPD technique measures the power changes in the far field pattern, i.e. spatial intensity modulation in two dimensions. Conducting polymers, such as polyaniline and polypyrrole, have been reported to undergo a reversible change in conductivity upon exposure to chemical vapors. It is found that the conductivity change is accompanied by optical property change in the material. Therefore, polyaniline and polypyrrole were selected as the modified cladding material for the detection of hydrochloride (HCl), ammonia (NH3), hydrazine (H4N2), and dimethyl-methl-phosphonate (DMMP) {a nerve agent, sarin stimulant}, respectively. Several sensors were prepared and successfully tested. The results showed dramatic improvement in the sensor sensitivity, when the MPD method was applied. In this paper, an overview on the developed class of fiber optic sensors is presented and supported with successful achieved results.

  8. Microstructured optical fibers - Fundamentals and applications

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper; Bjarklev, Anders Overgaard

    2006-01-01

    In recent years optical fibers having a complex microstructure in the transverse plane have attracted much attention from both researchers and industry. Such fibers can either guide light through total internal reflection or the photonic bandgap effect. Among the many unique applications offered by these fibers are mode guidance in air, highly flexible dispersion engineering, and the use of very heterogeneous material combinations. In this paper, we review the different types and applications of microstructured optical fibers, with particular emphasis on recent advances in the field.

  9. MEMS based optical cross connects for fiber optical communication

    OpenAIRE

    Zickar, Michael; de Rooij, Nico

    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...

  10. Micromachined fiber optic Fabry-Perot underwater acoustic probe

    Science.gov (United States)

    Wang, Fuyin; Shao, Zhengzheng; Hu, Zhengliang; Luo, Hong; Xie, Jiehui; Hu, Yongming

    2014-08-01

    One of the most important branches in the development trend of the traditional fiber optic physical sensor is the miniaturization of sensor structure. Miniature fiber optic sensor can realize point measurement, and then to develop sensor networks to achieve quasi-distributed or distributed sensing as well as line measurement to area monitoring, which will greatly extend the application area of fiber optic sensors. The development of MEMS technology brings a light path to address the problems brought by the procedure of sensor miniaturization. Sensors manufactured by MEMS technology possess the advantages of small volume, light weight, easy fabricated and low cost. In this paper, a fiber optic extrinsic Fabry-Perot interferometric underwater acoustic probe utilizing micromachined diaphragm collaborated with fiber optic technology and MEMS technology has been designed and implemented to actualize underwater acoustic sensing. Diaphragm with central embossment, where the embossment is used to anti-hydrostatic pressure which would largely deflect the diaphragm that induce interferometric fringe fading, has been made by double-sided etching of silicon on insulator. By bonding the acoustic-sensitive diaphragm as well as a cleaved fiber end in ferrule with an outer sleeve, an extrinsic Fabry-Perot interferometer has been constructed. The sensor has been interrogated by quadrature-point control method and tested in field-stable acoustic standing wave tube. Results have been shown that the recovered signal detected by the sensor coincided well with the corresponding transmitted signal and the sensitivity response was flat in frequency range from 10 Hz to 2kHz with the value about -154.6 dB re. 1/?Pa. It has been manifest that the designed sensor could be used as an underwater acoustic probe.

  11. Thermal Strain Analysis of Optic Fiber Sensors

    Directory of Open Access Journals (Sweden)

    Chih-Ying Huang

    2013-01-01

    Full Text Available 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 stresses can be generated due to a mismatch of thermal expansion coefficients between the optical fiber and host structure. The optical fiber thermal strain induced by the host structure is transferred via the adhesive layer and protective coating. In this investigation, an analytical expression of the thermal strain and stress in the optical fiber is presented. The theoretical predictions are validated using the finite element method. Numerical results show that the thermal strain and stress are linearly dependent on the difference in thermal expansion coefficients between the optical fiber and host structure and independent of the thermal expansion coefficients of the adhesive and coating.

  12. Optical fiber thermometers; Thermometres a fibre optique

    Energy Technology Data Exchange (ETDEWEB)

    Ferdinand, P. [CEA Saclay, Dir. de la Recherche Technologique, List, 91 - Gif sur Yvette (France)

    2003-09-01

    Optical fiber temperature captors are classified in two classes: the measure being carried out without or with contact. It concerns on one side the pyrometers, based on the detection of the infrared flux emitted by the materials whose surface temperature is to be determined and for which the fiber is used only to transport the measure point and on the other side the captors and the fiber captors networks of intrinsic type (fiber plays the role of transducer) and of extrinsic type (the fiber is not transducer). All these measure methods are compared in this work. (O.M.)

  13. Internal and External Optical Feedback Effect in Fiber Linear Lasers

    Directory of Open Access Journals (Sweden)

    Junping Zhou

    2013-09-01

    Full Text Available In this paper, models of internal and external optical feedback effect in fiber linear lasers have been presented. The effects of optical feedback could be equivalent to the variation of laser cavity loss, and the output expressions of two models are deduced. According to the simulation results, the optical feedback system in fiber linear lasers has the same phase sensitivity as the traditional self-mixing effect in semiconductor lasers. The experimental results show a good agreement with the simulated results. Comparing the output of internal structure with that of external structure, we can conclude that the internal optical feedback system can get higher output gain and stripe depth, which reveals that the internal feedback structure has better sensing characteristics

  14. Optical Fiber for High-Power Optical Communication

    OpenAIRE

    Kenji Kurokawa

    2012-01-01

    We examined optical fibers suitable for avoiding such problems as the fiber fuse phenomenon and failures at bends with a high power input. We found that the threshold power for fiber fuse propagation in photonic crystal fiber (PCF) and hole-assisted fiber (HAF) can exceed 18 W, which is more than 10 times that in conventional single-mode fiber (SMF). We considered this high threshold power in PCF and HAF to be caused by a jet of high temperature fluid penetrating the air holes. We showed exam...

  15. Study on temperature and current sensors based on optical driving optical fiber transmission

    Science.gov (United States)

    Wang, Dong-sheng; Pan, Wei-wei

    2013-03-01

    A sensing measurement scheme based on the optical fiber coupling optical driving converting probe is proposed. Using the optical feedback stabilized 5 mW LD as illuminant, the optical driving distance is 100 m. The power of designed low-consumption temperature-sensitive sensor probe is small to 2.2 mW. The design idea of this new sensor and the key technology of realizing optical driving are introduced in this paper. Experimental results show that the temperature sensor with high resolution can resist high-voltage and electromagnetic interference, and has high sensitivity and precision with 1000 Hz/°C.

  16. Protective coating and hyperthermal atomic oxygen texturing of optical fibers used for blood glucose monitoring

    Science.gov (United States)

    Banks, Bruce A. (Inventor)

    2008-01-01

    Disclosed is a method of producing cones and pillars on polymethylmethacralate (PMMA) optical fibers for glucose monitoring. The method, in one embodiment, consists of using electron beam evaporation to deposit a non-contiguous thin film of aluminum on the distal ends of the PMMA fibers. The partial coverage of aluminum on the fibers is randomly, but rather uniformly distributed across the end of the optical fibers. After the aluminum deposition, the ends of the fibers are then exposed to hyperthermal atomic oxygen, which oxidizes the areas that are not protected by aluminum. The resulting PMMA fibers have a greatly increased surface area and the cones or pillars are sufficiently close together that the cellular components in blood are excluded from passing into the valleys between the cones and pillars. The optical fibers are then coated with appropriated surface chemistry so that they can optically sense the glucose level in the blood sample than that with conventional glucose monitoring.

  17. Fiber optic communications fundamentals and applications

    CERN Document Server

    Kumar, Shiva

    2014-01-01

    Fiber-optic communication systems have advanced dramatically over the last four decades, since the era of copper cables, resulting in low-cost and high-bandwidth transmission. Fiber optics is now the backbone of the internet and long-distance telecommunication. Without it we would not enjoy the benefits of high-speed internet, or low-rate international telephone calls. This book introduces the basic concepts of fiber-optic communication in a pedagogical way. The important mathematical results are derived by first principles rather than citing research articles. In addition, physical interpre

  18. Absorbance Response of Graphene Oxide Coated on Tapered Multimode Optical Fiber Towards Liquid Ethanol

    Science.gov (United States)

    Girei, S. H.; Shabaneh, A. A.; Lim, H. M.; Huang, N. H.; Mahdi, M. A.; Yaacob, M. H.

    2015-04-01

    The investigation of graphene oxide (GO) for sensing applications is attractive due to its nanoscale structure and its sensing properties has yet to be fully understood. In this paper, optical response of GO coated optical fiber sensor towards ethanol is described. GO was coated onto a multimode tapered optical fiber by drop-casting technique. The coated fiber was exposed to 5-40% of ethanol in water. The films were characterized with field emission scanning electron microscope, ultraviolet-visible spectroscopy and Raman spectroscopy. The sensing is based on changes following the absorbance of the GO coated optical fiber upon exposure to ethanol. The developed sensor shows fast response and recovery with duration of 22 and 20 s, respectively. The sensor also displays high repeatability and reversibility.

  19. Polymer optical fiber bragg grating sensors : measuring acceleration

    DEFF Research Database (Denmark)

    Stefani, Alessio; Yuan, Scott Wu

    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.

  20. Long-gauge length embedded fiber optic ultrasonic sensor for large-scale concrete structures

    Science.gov (United States)

    Yuan, Libo; Zhou, Limin; Jin, Wei

    2004-02-01

    A fiber optic ultrasonic sensor based on Fizeau interferometer has been developed and demonstrated. A helium-neon laser light source with wavelength 0.6328 ?m is used in our experiment. A special feature is its Fizeau configuration, which enables one to eliminate much undesirable noise by combining both the reference arm and the sensing arm within the same length of fiber. The dynamic response model of photo-elastic effect of ultrasonic wave and optical fiber is established. The fiber optic ultrasonic sensor experimental results are obtained and compared with the convenient PZT transducer.

  1. Side-emitting fiber optic position sensor

    Science.gov (United States)

    Weiss, Jonathan D. (Albuquerque, NM)

    2008-02-12

    A side-emitting fiber optic position sensor and method of determining an unknown position of an object by using the sensor. In one embodiment, a concentrated beam of light source illuminates the side of a side-emitting fiber optic at an unknown axial position along the fiber's length. Some of this side-illuminated light is in-scattered into the fiber and captured. As the captured light is guided down the fiber, its intensity decreases due to loss from side-emission away from the fiber and from bulk absorption within the fiber. By measuring the intensity of light emitted from one (or both) ends of the fiber with a photodetector(s), the axial position of the light source is determined by comparing the photodetector's signal to a calibrated response curve, look-up table, or by using a mathematical model. Alternatively, the side-emitting fiber is illuminated at one end, while a photodetector measures the intensity of light emitted from the side of the fiber, at an unknown position. As the photodetector moves further away from the illuminated end, the detector's signal strength decreases due to loss from side-emission and/or bulk absorption. As before, the detector's signal is correlated to a unique position along the fiber.

  2. Fiber optic sensor for methanol quantification in biodiesel

    Science.gov (United States)

    Kawano, Marianne S.; Kamikawachi, Ricardo Canute; Fabris, José L.; Müller, Marcia

    2014-05-01

    In this work a refractometric sensor for assessment of methanol presence in biodiesel is reported. The transducer relies on the interference between the forward and back propagating modes of a single long period grating, written close to an end-face mirror optical fiber. The sensing method is thermally assisted in order to overcome the drawback caused by the high refractive index (close to the fiber cladding index) of methanol-biodiesel blends at low temperatures. Sensor showed a combined standard uncertainty of 0.6 % v/v of methanol in biodiesel for a confidence level of 68.27%, within the methanol concentration ranging from 0 to 25 % v/v.

  3. Applicability of optical fiber Bragg grating in radiation environment

    International Nuclear Information System (INIS)

    Fiber Bragg grating (FBG) is a kind of an optical device developing rapidly in these years. FBGs have capability of multiparameter sensing at many points along a fiber. To assess the applicability of FBRs to nuclear plants, influences of jackets' degradation and temperature sensitivity in gamma-ray environment were investigated. It was shown that Bragg peaks were not shifted by gamma-ray and have no dependence on the existence of jackets. Moreover, temperature sensitivities of FBGs were not influenced by gamma-ray irradiation. (author)

  4. Observation of polymer optical fiber fuse

    Science.gov (United States)

    Mizuno, Yosuke; Hayashi, Neisei; Tanaka, Hiroki; Nakamura, Kentaro; Todoroki, Shin-ichi

    2014-01-01

    Although high-transmission-capacity optical fibers are in demand, the problem of the fiber fuse phenomenon needs to be resolved to prevent the destruction of fibers. As polymer optical fibers become more prevalent, clarifying their fuse properties has become important. Here, we experimentally demonstrate a fuse propagation velocity of 21.9 mm/s, which is 1-2 orders of magnitude slower than that in standard silica fibers. The achieved threshold power density and proportionality constant between the propagation velocity and the power density are 1/180 of and 17 times the values for silica fibers, respectively. An oscillatory continuous curve instead of periodic voids is formed after the passage of the fuse. An easy fuse termination method is also presented.

  5. Prospective Vitreous Materials For Infrared Fiber Optics

    Science.gov (United States)

    Bendow, Bernard; Drexhage, Martin G.

    1982-02-01

    Fiber optics operating in the mid-infrared (IR) offer the potential for lower losses and better tolerance to nuclear radiation than current silicate-based fibers. Moreover, mid-IR fibers may be useful for a variety of shorter distance applications such as laser surgery, spot welding, and infrared integrated optics. Although a wide array of potentially highly transmissive mid-IR materials are available in bulk form, most are not suitable for fiber fabrication. Recently, however, a variety of new multicomponent glasses based on the fluorides of heavy metals have been developed, which may offer the best prospects to date for high performance mid-IR fibers. A critical comparison of the advantages as well as the problems associated with various prospective materials and fiber fabrication techniques is given.

  6. Review of Brillouin-active fiber-based acousto-optic sensors

    Science.gov (United States)

    Yu, Chung; Kim, Yong K.

    2002-09-01

    Brillouin active fibers, based on stimulated Brillouin scattering (sBs), have been extensively studied as ambient sensors by exploiting quartz fiber intrinsic acoustooptic properties[5-7]. Thus, the fiber is inherently a sensor, as opposed to fiber Bragg gratings, in which lines have to be photolithographically etched on the fiber by UV light. The sBs threshold enables sensing to be switched on and off in standard communication fibers, leading to fiber dual use. They have also been examined as combined optical and acoustic waveguides for joint optical and acoustic sensing. Success of these sensors lies in lowering the sBs threshold to achieve low power, short fiber length and multi-Stokes line generation. Numerous schemes have been proposed and tested, such as fiber rings, and they will be surveyed. The inherent optical feedback by the back-scattered Stokes wave leads to instabilities in the form of optical chaos. This paradigm of optical chaos serves as a test for fundamental study of chaos and its suppression and exploitation in practical application in communication and sensing.

  7. Optical design of a high power fiber optic coupler

    International Nuclear Information System (INIS)

    Fiber optic beam delivery systems are replacing conventional mirror delivery systems for many reasons (e.g., system flexibility and redundancy, stability, and ease of alignment). Commercial products are available that use of fiber optic delivery for laser surgery and materials processing. Also, pump light of dye lasers can be delivered by optical fibers. Many laser wavelengths have been transported via optical fibers; high power delivery has been reported for argon, Nd:YAG, and excimer. We have been developing fiber optic beam delivery systems for copper vapor laser light; many of the fundamental properties of these systems are applicable to other high power delivery applications. A key element of fiber optic beam delivery systems is the coupling of laser light into the optical fiber. For our application this optical coupler must be robust to a range of operating parameters and laser characteristics. We have access to a high power copper vapor laser beam that is generated by a master oscillator/power amplifier (MOPA) chain comprised of three amplifiers. The light has a pulse width of 40--50 nsec with a repetition rate of about 4 kHz. The average power (nominal) to be injected into a fiber is 200 W. (We will refer to average power in this paper.) In practice, the laser beam's direction and collimation change with time. These characteristics plus other mechanical and operational constraints make it difficult for our coupler to be opto-mechanically referenced to the laser beam. We describe specifications, design, and operation of an optical system that couples a high-power copper vapor laser beam into a large core, multimode fiber. The approach used and observations reported are applicable to fiber optic delivery applications. 6 refs., 6 figs

  8. Fiber optic pH sensing with long wavelength excitable Schiff bases in the pH range of 7.0-12.0.

    Science.gov (United States)

    Derinkuyu, Sibel; Ertekin, Kadriye; Oter, Ozlem; Denizalti, Serpil; Cetinkaya, Engin

    2007-04-01

    Most of the fluorescent pH probes work near neutral or acidic regions of the pH scale. In this work, two different fluorescent Schiff bases, chloro phenyl imino propenyl aniline (CPIPA) and nitro phenyl imino propenyl aniline (NPIPA), have been investigated for pH sensing in the alkaline region. Absorption and emission based spectral data, quantum yield, fluorescence lifetime, photostability and acidity constant (pK(a)) of the Schiff bases were determined in conventional solvents and in PVC. The long wavelength excitable immobilized Schiff bases CPIPA (lambda(ex)=556 nm) and NPIPA (lambda(ex)=570 nm) exhibited absorption and emission based optical response to proton in the pH range of 8.0-12.0 and 7.0-12.0, respectively. Response of the CPIPA was fully reversible within the dynamic working range. The response times were between 3-13 min. A relative signal change of 95% and 96% have been achieved for sensor dyes of CPIPA and NPIPA, respectively. The CPIPA displayed better fluorescence quantum yield (varphi(F)=3.7 x 10(-1)) and higher matrix compatibility compared to NPIPA (varphi(F)=1.6 x 10(-1)) in immobilized PVC. The CPIPA and NPIPA exhibited a slight cross sensitivity to the ions of Hg(+) and Fe(3+), respectively. PMID:17386792

  9. Fiber optic pH sensing with long wavelength excitable Schiff bases in the pH range of 7.0-12.0

    International Nuclear Information System (INIS)

    Most of the fluorescent pH probes work near neutral or acidic regions of the pH scale. In this work, two different fluorescent Schiff bases, chloro phenyl imino propenyl aniline (CPIPA) and nitro phenyl imino propenyl aniline (NPIPA), have been investigated for pH sensing in the alkaline region. Absorption and emission based spectral data, quantum yield, fluorescence lifetime, photostability and acidity constant (pK a) of the Schiff bases were determined in conventional solvents and in PVC. The long wavelength excitable immobilized Schiff bases CPIPA (? ex = 556 nm) and NPIPA (? ex = 570 nm) exhibited absorption and emission based optical response to proton in the pH range of 8.0-12.0 and 7.0-12.0, respectively. Response of the CPIPA was fully reversible within the dynamic working range. The response times were between 3-13 min. A relative signal change of 95% and 96% have been achieved for sensor dyes of CPIPA and NPIPA, respectively. The CPIPA displayed better fluorescence quantum yield (? F = 3.7 x 10-1) and higher matrix compatibility compared to NPIPA (? F = 1.6 x 10-1) in immobilized PVC. The CPIPA and NPIPA exhibited a slight cross sensitivity to the ions of Hg+ and Fe3+, respectively

  10. Fiber optic sensor integration system and measurement technique

    Science.gov (United States)

    Stinson-Bagby, Kelly L.; Marcus, Michael A.; Fielder, Robert S.

    2004-03-01

    Fiber optic measurement systems are on the cutting edge of instrumentation for many industries from military and government applications to commercial needs such as the automotive, aerospace, and power turbine industries. Measurement parameters including temperature, pressure, and strain can provide valuable information. Sensor mapping allows for larger scale monitoring capabilities and provide flexibility in sensing applications. A sensor and readout system is being developed to expand the capabilities of fiber optic sensing. Several iterations of multiplexed sensors have been tested using a high-resolution fiber optic coupled dual Michelson interferometer based-instrument that has the capability of reading gaps of 25?m to 6.5mm. This measurement range opened the opportunity to read several different sensors on the same fiber, i.e. the same channel. Sensor strings combining temperature and strain extrinsic Fabry-Perot interferometric sensors were tested. These sensor strings produced were either serial multiplexed, parallel multiplexed, or a combination. This paper will discuss the capabilities of the sensors and instrumentation systems developed.

  11. Critical applications of fiber optic sensors in nuclear industry

    International Nuclear Information System (INIS)

    Sensors have a useful role in many industries for monitoring processes and environmental parameters. They provide vital feedback either to control vital process conditions or to activate preset safety procedures. Off late, optical fiber based sensors are gaining importance. They offer unique advantages like distributed sensing and immune to electromagnetic interference. Fast Breeder Reactors (FBRs) use liquid sodium as coolant. The heat is transferred from the reactor core to the steam generator through the coolant loops. Continuous monitoring of temperature in the coolant loops of FBRs is important for the safety of the reactors. The advantage of fiber optic sensor over all other types of temperature sensors is that it provides sensing over the length of the sodium pipeline. Temperature can be measured at each zone along the length of the fiber sensor. At Kalpakkam, India, a programme on development of Raman Distributed Temperature Sensor (RDTS) for deployment on sodium circuits in FBR was undertaken; for distributed temperature measurement and sodium leak detection. This talk presents the author's experience in adopting the fiber optic sensors for nuclear applications

  12. Fiber Optic Communications Technology. A Status Report.

    Science.gov (United States)

    Hull, Joseph A.

    Fiber optic communications (communications over very pure glass transmission channels of diameter comparable to a human hair) is an emerging technology which promises most improvements in communications capacity at reasonable cost. The fiber transmission system offers many desirable characteristics representing improvements over conventional…

  13. Optical fibers and sensors for chemistry

    International Nuclear Information System (INIS)

    The idea of using optical fibers in nuclear environment occurs as soon as 1967, too soon for practical realizations. In 1973 the first glass fibers were made available in Switzerland. From 1973 to 1988 three periods show the development: conception from 1973 to 1978, technique strengthening from 1978 to 1983 and nuclear and non nuclear industrial development since 1983. 45 refs., 27 figs

  14. Fiber Optic Pressure Sensor Array Project

    National Aeronautics and Space Administration — VIP Sensors proposes to develop a Fiber Optic Pressure Sensor Array for measuring air flow pressure at multiple points on the skin of aircrafts for Flight Load Test...

  15. Fiber Optic Pressure Sensor Array Project

    National Aeronautics and Space Administration — VIP Sensors proposes to develop a Fiber Optic Pressure Sensor Array System for measuring air flow pressure at multiple points on the skin of aircrafts for Flight...

  16. Fiber optic telemetry techniques in fusion environments

    International Nuclear Information System (INIS)

    The use of fiber optic communication links in fusion research is widespread. The applications range from the control and monitoring of simple switches to integrated communications systems which integrate machine control, data acquisition, and video monitoring onto a common network

  17. Fiber optics speckle interferometer for diffusivity measurements

    OpenAIRE

    Paoletti, D.; Schirripa Spagnolo, G.

    1993-01-01

    A digital speckle pattern interferometer with optical fibers is proposed for the real time measurement of the diffusion coefficient of liquid binary mixtures. Some examples of application of the technique are reported.

  18. Stable transmission of radio frequency signals on fiber links using interferomectric delay sensing

    International Nuclear Information System (INIS)

    The authors demonstrate distribution of a 2850 MHz rf signal over stabilized optical fiber links. For a 2.2 km link they measure an rms drift of 19.4 fs over 60 h, and for a 200 m link an rms drift of 8.4 fs over 20 h. The rf signals are transmitted as amplitude modulation on a continuous optical carrier. Variations in the delay length are sensed using heterodyne interferometry and used to correct the rf phase. The system uses standard fiber telecommunications components.

  19. Development of prototype fiber optics dosimeter for remote radiation measurements

    International Nuclear Information System (INIS)

    Optical fiber dosimetry has been studied as an emerging method of monitoring radiation remotely in difficult to access and hazardous areas and is suitable for use in confined environments that may be inaccessible using existing dosimeters. Being light weight and non intrusive, optical fibers provide several advantages in the field of dosimetry like resistant to electromagnetic interferences. An extrinsic architecture, where the radiation-sensing component is spliced or coupled to an optical fiber, is employed in this work. A prototype single channel fiber optic based remote radiation measurement system with BaFBr:Eu sensor, which has a wide linear dose response, is developed at Radiological Safety Division, IGCAR. High sensitive BaFBr:Eu2+ storage phosphor of 10 mm dia and 4 mm thickness has been successfully synthesized using high temperature solid state diffusion route in a reducing atmosphere. Optical characteristics of the BaFBr:Eu pellet were studied by taking Photoluminescence (PL) and Photo stimulated luminescence (PSL) measurements. PL emission wavelength is measured to be 390 nm. The BaFBr:Eu is irradiated for various absorbed doses in a gamma chamber at 213 Gy/hr using 60Co standard source (BRIT make) available at RSD, IGCAR

  20. Polymeric Optical Fibres for Biomedical Sensing

    OpenAIRE

    Krehel, M P

    2014-01-01

    In this thesis we focus on the integration of optical fibres in textiles to create wearable sensing systems. In the introduction (Chapter 3) we describe the basics of light guiding in optical fibres and methods of lateral light coupling. Subsequently, a literature review and motivation are presented. Afterwards two main parts can be differentiated. In the first one (Chapters 4, 5) a new method of continuous extrusion of optical fibres and their medical sensing application using photoplethysmo...

  1. Measurement of Faraday rotation in twisted optical fiber using rotating polarization and analog phase detection

    International Nuclear Information System (INIS)

    We demonstrated phase modulation of rotating linearly polarized light by current-induced Faraday rotation in a single mode optical fiber and used the technique to measure the current in ZT-40M, a Reversed-Field Pinch. We have also demonstrated the practicality of using twisted sensing fiber to overcome the problems associated with linear birefringence

  2. Real time sensing of structural glass fiber reinforced composites by using embedded PVA - carbon nanotube fibers

    Directory of Open Access Journals (Sweden)

    Marioli-Riga Z.

    2010-06-01

    Full Text Available Polyvinyl alcohol - carbon nanotube (PVA-CNT fibers had been embedded to glass fiber reinforced polymers (GFRP for the structural health monitoring of the composite material. The addition of the conductive PVA-CNT fiber to the nonconductive GFRP material aimed to enhance its sensing ability by means of the electrical resistance measurement method. The test specimen’s response to mechanical load and the in situ PVA-CNT fiber’s electrical resistance measurements were correlated for sensing and damage monitoring purposes. The embedded PVA-CNT fiber worked as a sensor in GFRP coupons in tensile loadings. Sensing ability of the PVA-CNT fibers was also demonstrated on an integral composite structure. PVA-CNT fiber near the fracture area of the structure recorded very high values when essential damage occurred to the structure. A finite element model of the same structure was developed to predict axial strains at locations of the integral composite structure where the fibers were embedded. The predicted FEA strains were correlated with the experimental measurements from the PVA-CNT fibers. Calculated and experimental values were in good agreement, thus enabling PVA-CNT fibers to be used as strain sensors.

  3. Fiber-Optic Vibration Sensor Based on Multimode Fiber

    Directory of Open Access Journals (Sweden)

    I. Lujo

    2008-06-01

    Full Text Available The purpose of this paper is to present a fiberoptic vibration sensor based on the monitoring of the mode distribution in a multimode optical fiber. Detection of vibrations and their parameters is possible through observation of the output speckle pattern from the multimode optical fiber. A working experimental model has been built in which all used components are widely available and cheap: a CCD camera (a simple web-cam, a multimode laser in visible range as a light source, a length of multimode optical fiber, and a computer for signal processing. Measurements have shown good agreement with the actual frequency of vibrations, and promising results were achieved with the amplitude measurements although they require some adaptation of the experimental model. Proposed sensor is cheap and lightweight and therefore presents an interesting alternative for monitoring large smart structures.

  4. Fiber Optic Polishing by CO2 Lasers

    Science.gov (United States)

    Er, Ibrahim G.; Ozer, M.

    2007-04-01

    In this study, mechanical and laser polishing of fiber optic surfaces were done and changing of gain (loss decreasing) were determined. It was observed that the polishing by carbon dioxide laser beam decreases the loss in the efficiency instead of cutting by fiber optic cables were used and the losses are measured as decibel (dB). The application time with respect to efficiency was investigated and minimum loss was determined in the six second laser beam applications.

  5. Sensing features of long period gratings in hollow core fibers.

    Science.gov (United States)

    Iadicicco, Agostino; Campopiano, Stefania

    2015-01-01

    We report on the investigation of the sensing features of the Long-Period fiber Gratings (LPGs) fabricated in hollow core photonic crystal fibers (HC-PCFs) by the pressure assisted Electric Arc Discharge (EAD) technique. In particular, the characterization of the LPG in terms of shift in resonant wavelengths and changes in attenuation band depth to the environmental parameters: strain, temperature, curvature, refractive index and pressure is presented. The achieved results show that LPGs in HC-PCFs represent a novel high performance sensing platform for measurements of different physical parameters including strain, temperature and, especially, for measurements of environmental pressure. The pressure sensitivity enhancement is about four times greater if we compare LPGs in HC and standard fibers. Moreover, differently from LPGs in standard fibers, these LPGs realized in innovative fibers, i.e., the HC-PCFs, are not sensitive to surrounding refractive index. PMID:25855037

  6. Sensing Features of Long Period Gratings in Hollow Core Fibers

    Directory of Open Access Journals (Sweden)

    Agostino Iadicicco

    2015-04-01

    Full Text Available We report on the investigation of the sensing features of the Long-Period fiber Gratings (LPGs fabricated in hollow core photonic crystal fibers (HC-PCFs by the pressure assisted Electric Arc Discharge (EAD technique. In particular, the characterization of the LPG in terms of shift in resonant wavelengths and changes in attenuation band depth to the environmental parameters: strain, temperature, curvature, refractive index and pressure is presented. The achieved results show that LPGs in HC-PCFs represent a novel high performance sensing platform for measurements of different physical parameters including strain, temperature and, especially, for measurements of environmental pressure. The pressure sensitivity enhancement is about four times greater if we compare LPGs in HC and standard fibers. Moreover, differently from LPGs in standard fibers, these LPGs realized in innovative fibers, i.e., the HC-PCFs, are not sensitive to surrounding refractive index.

  7. Sensing Features of Long Period Gratings in Hollow Core Fibers

    Science.gov (United States)

    Iadicicco, Agostino; Campopiano, Stefania

    2015-01-01

    We report on the investigation of the sensing features of the Long-Period fiber Gratings (LPGs) fabricated in hollow core photonic crystal fibers (HC-PCFs) by the pressure assisted Electric Arc Discharge (EAD) technique. In particular, the characterization of the LPG in terms of shift in resonant wavelengths and changes in attenuation band depth to the environmental parameters: strain, temperature, curvature, refractive index and pressure is presented. The achieved results show that LPGs in HC-PCFs represent a novel high performance sensing platform for measurements of different physical parameters including strain, temperature and, especially, for measurements of environmental pressure. The pressure sensitivity enhancement is about four times greater if we compare LPGs in HC and standard fibers. Moreover, differently from LPGs in standard fibers, these LPGs realized in innovative fibers, i.e., the HC-PCFs, are not sensitive to surrounding refractive index. PMID:25855037

  8. Moire-Fringe-Based Fiber Optic Tiltmeter for Structural Health Monitoring

    International Nuclear Information System (INIS)

    This paper presents a novel fiber optic tiltmeter system for the health monitoring of large-size structures. The system is composed of a sensor head, a light control unit and a signal processing unit. The sensing mechanism of the sensor head is based on a novel integration of the moire fringe phenomenon with fiber optics to achieve a robust performance in addition to its immunity to EM interference, easy ratting, and low cost. In this paper, a prototype of the fiber optic tiltmeter system has been developed successfully. A low-cost light control unit has been developed to drive the system's optic and electronic components. From an experimental test, the fiber optic tiltmeter is proven to be a prospective sensor for the monitoring of the tilting angle of civil structure with a good linearity. Finally, the test also successfully demonstrates the performance and the potential of the novel fiber optic tiltmeter system to monitor the health of civil infrastructures.

  9. A Study on the Security of Infrastructure using fiber Optic Scattering Sensors

    International Nuclear Information System (INIS)

    We have studied tile detection techniques, which can determine the location and the weight of an intruder into infrastructure, by using fiber-optic ROTDR (Rayleigh optical time domain reflectometry) sensor and fiber-optic BOTDA (Brillouin Optical time domain analysis) sensor, which can use an optical fiber longer than that of ROTDR sensor Fiber-optic sensing plates of ROTDR sensor, which arc buried in sand, were prepared to respond the intruder effects. The signal of ROTDR was analyzed to confirm the detection performance. The constructed ROTDR could be used up to 10km at the pulse width of 30ns. The location error was less than 2 m and the weight could be detected as 4 grades, such as 20kgf, 40kgf, 60kgf and 80kgf. Also, fiber optic BOTDA sensor was developed to be able to detect intrusion effect through an optical fiber of tells of kilometers longer than ROTDR sensor. fiber-optic BOTDA sensor was constructed with 1 laser diode and 2 electro-optic modulators. The intrusion detection experiment was performed by the strain inducing set-up installed on an optical table to simulate all intrusion effect. In the result of this experiment, the intrusion effort was well detected as the distance resolution of 3m through the fiber length of about 4.81km during 1.5 seconds

  10. Tunable Polymer Fiber Bragg Grating (FBG) Inscription: Fabrication of Dual-FBG Temperature Compensated Polymer Optical Fiber Strain Sensors

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Stefani, Alessio

    2012-01-01

    We demonstrate stable wavelength tunable inscription of polymer optical fiber Bragg gratings (FBGs). By straining the fiber during FBG inscription, we linearly tune the center wavelength over 7 nm with less than 1% strain. Above 1% strain, the tuning curve saturates and we show a maximum tuning of 12 nm with 2.25% strain. We use this inscription method to fabricate a dual-FBG strain sensor in a poly (methyl methacrylate) single-mode microstructured polymer optical fiber and demonstrate temperature compensated strain sensing around 850 nm.

  11. An In-Reflection Strain Sensing Head Based on a Hi-Bi Photonic Crystal Fiber

    Directory of Open Access Journals (Sweden)

    Manuel Lopez-Amo

    2013-06-01

    Full Text Available A photonic crystal fiber-based sensing head is proposed for strain measurements. The sensor comprises a Hi-Bi PCF sensing head to measure interferometric signals in-reflection. An experimental background study of the sensing head is conducted through an optical backscatter reflectometer confirming the theoretical predictions, also included. A cost effective setup is proposed where a laser is used as illumination source, which allows accurate high precision strain measurements. Thus, a sensitivity of ~7.96 dB/me was achieved in a linear region of 1,200 ?e.

  12. Fiber optic, Fabry-Perot high temperature sensor

    Science.gov (United States)

    James, K.; Quick, B.

    1984-11-01

    A digital, fiber optic temperature sensor using a variable Fabry-Perot cavity as the sensor element was analyzed, designed, fabricated, and tested. The fiber transmitted cavity reflection spectra is dispersed then converted from an optical signal to electrical information by a charged coupled device (CCD). A microprocessor-based color demodulation system converts the wavelength information to temperature. This general sensor concept not only utilizes an all-optical means of parameter sensing and transmitting, but also exploits microprocessor technology for automated control, calibration, and enhanced performance. The complete temperature sensor system was evaluated in the laboratory. Results show that the Fabry-Perot temperature sensor has good resolution (0.5% of full seale), high accuracy, and potential high temperature ( 1000 C) applications.

  13. Advanced fiber components for optical networks

    OpenAIRE

    Ylä-Jarkko, Kalle

    2004-01-01

    Due to the tremendous growth in data traffic and the rapid development in optical transmission technologies, the limits of the transmission capacity available with the conventional erbium-doped amplifiers (EDFA), optical filters and modulation techniques have nearly been reached. The objective of this thesis is to introduce new fiber-optic components to optical networks to cope with the future growth in traffic and also to bring down the size and cost of the transmission equipment. Improvemen...

  14. Diaphragm resonance-based fiber optic hydrophone

    Science.gov (United States)

    Saxena, Indu F.; Guzman, Narciso; Hui, Kaleonui J.; Pflanze, Stephen

    2010-04-01

    Passive hydrophones with a minimal footprint are useful for a variety of underwater monitoring applications; a fiber optic hydrophone is being investigated. Fiber optic hydrophones have been used in offshore moored applications, and have the capability to cover large areas. A resonant hydrophone using a fiber Bragg grating (FBG) transducer for limited bandwidth operation is described and compared with predicted diaphragm resonances. A battery-power readout system using a laser diode source that can typically operate for a full day, and can be used in off-mooring applications such as in autonomous underwater vehicles, is outlined.

  15. Ultrasensitive fiber optic sensors and their applications

    Science.gov (United States)

    Nam, SungHyun; Lee, Jon; Yin, Shizhuo; Reichard, Karl; Ruffin, Paul; Wang, Qing

    2005-03-01

    In this paper, a brief review on ultrasensitive fiber optic sensors and their applications, done recently at Penn State, is presented. Our discussions will mainly focus on two types of highly sensitive fiber optic sensors. One type is based on the combination of single resonant band long period gratings (LPGs) with the second refractive index matched polymer cladding layer. The other one is based on the LPGs fabricated in photonic nanostructured fibers and waveguides. It is found that a significantly increased sensitivity (two order plus) can be achieved by harnessing these approaches, which will benefit a variety of applications, in particular, low concentration chemical/biological agents detection.

  16. Fiber optic signal processing of ultrawideband signals

    Science.gov (United States)

    Mathis, Ronald F.; Floyd, William L.; Pappert, Stephen A.; Orazi, Richard J.

    1998-11-01

    Two L-band phase-matched fiber optic delay line channels and a broadband fiber optic RF signal processing filter have been designed, fabricated, tested, and evaluated. These two related RF photonic system development efforts are potentially useful in ELINT signal processing of ultrawideband signal. Specifically, two high performance optical delay lines operating at 1 GHz with a 500 MHz bandwidth have been prototype and show prototyped and show improved dynamic range and environmental phase tracking performance over conventional SAW delay lines. In addition, an eight-tap fiber optic transversal filter using wavelet amplitude weighting has been designed, fabricated, and tested in the 50 MHz to 20 GHz frequency range. A high pass wavelet filter useful for ultrawideband signal detection has been optically implemented, and test result presented for sensitivity and dynamic range are promising.

  17. Fiber Optic Sensors For Detection of Toxic and Biological Threats

    Directory of Open Access Journals (Sweden)

    Jianming Yuan

    2007-12-01

    Full Text Available Protection of public and military personnel from chemical and biological warfareagents is an urgent and growing national security need. Along with this idea, we havedeveloped a novel class of fiber optic chemical sensors, for detection of toxic and biologicalmaterials. The design of these fiber optic sensors is based on a cladding modificationapproach. The original passive cladding of the fiber, in a small section, was removed and thefiber core was coated with a chemical sensitive material. Any change in the opticalproperties of the modified cladding material, due to the presence of a specific chemicalvapor, changes the transmission properties of the fiber and result in modal powerredistribution in multimode fibers. Both total intensity and modal power distribution (MPDmeasurements were used to detect the output power change through the sensing fibers. TheMPD technique measures the power changes in the far field pattern, i.e. spatial intensitymodulation in two dimensions. Conducting polymers, such as polyaniline and polypyrrole,have been reported to undergo a reversible change in conductivity upon exposure tochemical vapors. It is found that the conductivity change is accompanied by optical propertychange in the material. Therefore, polyaniline and polypyrrole were selected as the modifiedcladding material for the detection of hydrochloride (HCl, ammonia (NH3, hydrazine(H4N2, and dimethyl-methl-phosphonate (DMMP {a nerve agent, sarin stimulant},respectively. Several sensors were prepared and successfully tested. The results showeddramatic improvement in the sensor sensitivity, when the MPD method was applied. In thispaper, an overview on the developed class of fiber optic sensors is presented and supportedwith successful achieved results.

  18. Chronology of Fabry-Perot Interferometer Fiber-Optic Sensors and Their Applications: A Review

    Directory of Open Access Journals (Sweden)

    Md. Rajibul Islam

    2014-04-01

    Full Text Available 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 interferometers. Fabry-Perot interferometer (FPI fiber-optic sensors have been extensively investigated for their exceedingly effective, simple fabrication as well as low cost aspects. In this study, a wide variety of FPI sensors are reviewed in terms of fabrication methods, principle of operation and their sensing applications. The chronology of the development of FPI sensors and their implementation in various applications are discussed.

  19. Theoretical investigation of absorption and sensitivity of nano-plasmonic fiber optic sensors

    Science.gov (United States)

    Salari, M.; Askari, H. R.

    2013-06-01

    In this paper, fiber-optic sensor based on surface plasmon resonance (SPR) is considered. The fiber-optic sensor is coated with thin nanoparticle metallic films. The nanoparticle metallic film consists of spherical metallic nanoparticles embedded in a host material. It is shown that sensitivity and absorption of sensor depends on number and type of films. It theoretically analyzed that the different states such as, fiber-optic sensor with a single thin layer of spherical gold or silver nanoparticle and a bimetallic arrangement of silver and gold nanoparticles. It also studied dependence of the sensitivity and absorption of sensor on the parameters such as gold particle size, film thickness, refractive index of host material, sensing region length, fiber core diameter, maximum absorption wavelength, half maximum width of the sensing medium and background refractive index of the sensing layer.

  20. Chronology of Fabry-Perot interferometer fiber-optic sensors and their applications: a review.

    Science.gov (United States)

    Islam, Md Rajibul; Ali, Muhammad Mahmood; Lai, Man-Hong; Lim, Kok-Sing; Ahmad, Harith

    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 interferometers. Fabry-Perot interferometer (FPI) fiber-optic sensors have been extensively investigated for their exceedingly effective, simple fabrication as well as low cost aspects. In this study, a wide variety of FPI sensors are reviewed in terms of fabrication methods, principle of operation and their sensing applications. The chronology of the development of FPI sensors and their implementation in various applications are discussed. PMID:24763250

  1. Automated photosensitivity enhancement in optical fiber tapers

    Scientific Electronic Library Online (English)

    Aleksander Sade, Paterno; Valmir de, Oliveira; Hypolito J., Kalinowski.

    2011-06-01

    Full Text Available An alternative technique that uses a flame-brush at high temperature to enhance UV light photosensitivity in an optical fiber is described. An extreme low-cost air aspirated propane-butane mini-torch is used, which produces a lower temperature flame than the one in the flame-brush original technique [...] . It is shown that this change in the previous technique is also capable of improving photosensitivity and allowing the fiber Bragg grating imprinting process to be accelerated. Since the flame-brush photosensitivity enhancement process is designed to operate in an automated fiber taper rig, the process was evaluated in optical fiber tapers with different diameters. In this case, changes in photosensitivity are observed in the tapers in addition to the intrinsic photosensitivity occurring in the pristine fiber without being tapered.

  2. Plastic optical fibers: properties and practical applications

    Science.gov (United States)

    Loch, Manfred, Jr.

    2004-10-01

    Driven by the increasing data traffic and the increasing demand for bandwidth optical fiber technologies play a greater role in todays and future data-communication networks. Although the well-known silica fiber have the potential of achieving very large bandwidth, this fiber is not the ideal medium for high bit rate data-communication for office and home applications because its small dimension requires well sophisticated components as well as installation technologies. This increases the total system cost, inevitably. However, the technologies of plastic (polymer) optical fibers (POF) and the devices for POF nowadays show rapid process /2/. So, we could benefit from the special advantages of these fibers over a wide field of applications, from decoration to local networks, including lighting, image guides and sensor technique. Today, inexpensive and robust POF transmission systems are available on the market with high bit rate capacity. Bus-systems, e.g. MOST and Byteflight, are applied in the rough automotive environment.

  3. Dynamically tunable optical bottles from an optical fiber

    DEFF Research Database (Denmark)

    Chen, Yuhao; Yan, Lu

    2012-01-01

    Optical fibers have long been used to impose spatial coherence to shape free-space optical beams. Recent work has shown that one can use higher order fiber modes to create more exotic beam profiles. We experimentally generate optical bottles from Talbot imaging in the coherent superposition of two fiber modes excited with long period gratings, and obtain a 28 ?m × 6 ?m bottle with controlled contrast up to 10.13 dB. Our geometry allows for phase tuning of one mode with respect to the other, which enables us to dynamically move the bottle in free space.

  4. Remote fiber sensors and optical amplification

    Science.gov (United States)

    Pontes, M. J.; Coelho, Thiago V. N.; Carvalho, Joel P.; Santos, J. L.; Guerreiro, A.

    2013-11-01

    This work discusses remote fiber sensors enabled by optical amplification. Continuous wave numerical modeling based on the propagation of pumps and signal lasers coupled to optical fibers explores Raman amplification schemes to predict the sensor's behavior. Experimental analyses report the results to a temperature remote optical sensor with 50 km distance between the central unit and the sensor head. An electrical interrogation scheme is used due to their low cost and good time response. Different architectures in remote sensor systems are evaluated, where diffraction gratings are the sensor element. A validation of calculated results is performed by experimental analyses and, as an application, the noise generated by Raman amplification in the remote sensors systems is simulated applying such numerical modeling. The analyses of sensors systems based on diffraction gratings requires optical broadband sources to interrogate the optical sensor unit, mainly in long period gratings that shows a characteristic rejection band. Therefore, the sensor distance is limited to a few kilometers due to the attenuation in optical fibers. Additional attenuation is introduced by the sensor element. Hence, to extend the distance in the optical sensor system, the optical amplification system is needed to compensate the losses in the optical fibers. The Raman amplification technology was selected mainly due to the flexibility in the gain bandwidth. The modeling can be applied to sensor systems that monitor sites located at long distances, or in places that the access is restricted due to harsh environment conditions in such cases conventional sensors are relatively fast deteriorated.

  5. Nonlinear fiber-optic strain sensor based on four-wave mixing in microstructured optical fiber

    DEFF Research Database (Denmark)

    Gu, Bobo; Yuan, Scott Wu

    2012-01-01

    We demonstrate a nonlinear fiber-optic strain sensor, which uses the shifts of four-wave mixing Stokes and anti-Stokes peaks caused by the strain-induced changes in the structure and refractive index of a microstructured optical fiber. The sensor thus uses the inherent nonlinearity of the fiber and does not require any advanced post-processing of the fiber. Strain sensitivity of -0.23 pm/mu epsilon is achieved experimentally and numerical simulations reveal that for the present fiber the sensitivity can be increased to -4.46 pm/mu epsilon by optimizing the pump wavelength and power.

  6. Photogrammetric Verification of Fiber Optic Shape Sensors on Flexible Aerospace Structures

    Science.gov (United States)

    Moore, Jason P.; Rogge, Matthew D.; Jones, Thomas W.

    2012-01-01

    Multi-core fiber (MCF) optic shape sensing offers the possibility of providing in-flight shape measurements of highly flexible aerospace structures and control surfaces for such purposes as gust load alleviation, flutter suppression, general flight control and structural health monitoring. Photogrammetric measurements of surface mounted MCF shape sensing cable can be used to quantify the MCF installation path and verify measurement methods.

  7. Ultra-low-loss optical fiber nanotapers

    Science.gov (United States)

    Brambilla, Gilberto; Finazzi, Vittoria; Richardson, David J.

    2004-05-01

    Optical fiber tapers with a waist size larger than 1µm are commonplace in telecommunications and sensor applications. However the fabrication of low-loss optical fiber tapers with subwavelength diameters was previously thought to be impractical due to difficulties associated with control of the surface roughness and diameter uniformity. In this paper we show that very-long ultra-low-loss tapers can in fact be produced using a conventional fiber taper rig incorporating a simple burner configuration. For single-mode operation, the optical losses we achieve at 1.55µm are one order of magnitude lower than losses previously reported in the literature for tapers of a similar size. SEM images confirm excellent taper uniformity. We believe that these low-loss structures should pave the way to a whole range of fiber nanodevices.

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

    DEFF Research Database (Denmark)

    Hu, Xiaolian; Saez-Rodriguez, D.

    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 325 nm HeCd laser. For the first time to the best of our knowledge, we study photoinduced birefringence effects in (m)POFBGs. To achieve this, highly reflective gratings were inscribed with the phase mask technique. They were then monitored in transmission with polarized light. For this, (m)POF sections a few cm in length containing the gratings were glued to angled silica fibers. Polarization dependent loss (PDL) and differential group delay (DGD) were computed from the Jones matrix eigenanalysis using an optical vectoranalyser. Maximum values exceeding several dB and a few picoseconds were obtained for the PDL and DGD, respectively. The response to lateral force was finally investigated. As it induces birefringence in addition to the photo-induced one, an increase of the PDL and DGD values were noticed.

  9. Fiber-Optic Sensor for Aircraft Lightning Current Measurement

    Science.gov (United States)

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George G.; Mata, Carlos T.; Mata, Angel G.; Snyder, Gary P.

    2012-01-01

    An electric current sensor based on Faraday rotation effect in optical fiber was developed for measuring aircraft lightning current. Compared to traditional sensors, the design has many advantages including the ability to measure total current and to conform to structure geometries. The sensor is also small, light weight, non-conducting, safe from interference, and free of hysteresis and saturation. Potential applications include characterization of lightning current waveforms, parameters and paths, and providing environmental data for aircraft certifications. In an optical fiber as the sensing medium, light polarization rotates when exposed to a magnetic field in the direction of light propagation. By forming closed fiber loops around a conductor and applying Ampere s law, measuring the total light rotation yields the enclosed current. A reflective polarimetric scheme is used, where polarization change is measured after the polarized light travels round-trip through the sensing fiber. The sensor system was evaluated measuring rocket-triggered lightning over the 2011 summer. Early results compared very well against a reference current shunt resistor, demonstrating the sensor s accuracy and feasibility in a lightning environment. While later comparisons show gradually increasing amplitude deviations for an undetermined cause, the overall waveforms still compared very well.

  10. Response Characterization of a Fiber Optic Sensor Array with Dye-Coated Planar Waveguide for Detection of Volatile Organic Compounds

    OpenAIRE

    Jae-Sung Lee; Na-Rae Yoon; Byoung-Ho Kang; Sang-Won Lee; Sai-Anand Gopalan; Hyun-Min Jeong; Seung-Ha Lee; Dae-Hyuk Kwon; Shin-Won Kang

    2014-01-01

    We have developed a multi-array side-polished optical-fiber gas sensor for the detection of volatile organic compound (VOC) gases. The side-polished optical-fiber coupled with a polymer planar waveguide (PWG) provides high sensitivity to alterations in refractive index. The PWG was fabricated by coating a solvatochromic dye with poly(vinylpyrrolidone). To confirm the effectiveness of the sensor, five different sensing membranes were fabricated by coating the side-polished optical-fiber us...

  11. Optically powered active sensing system for Internet Of Things

    Science.gov (United States)

    Gao, Chen; Wang, Jin; Yin, Long; Yang, Jing; Jiang, Jian; Wan, Hongdan

    2014-10-01

    Internet Of Things (IOT) drives a significant increase in the extent and type of sensing technology and equipment. Sensors, instrumentation, control electronics, data logging and transmission units comprising such sensing systems will all require to be powered. Conventionally, electrical powering is supplied by batteries or/and electric power cables. The power supply by batteries usually has a limited lifetime, while the electric power cables are susceptible to electromagnetic interference. In fact, the electromagnetic interference is the key issue limiting the power supply in the strong electromagnetic radiation area and other extreme environments. The novel alternative method of power supply is power over fiber (PoF) technique. As fibers are used as power supply lines instead, the delivery of the power is inherently immune to electromagnetic radiation, and avoids cumbersome shielding of power lines. Such a safer power supply mode would be a promising candidate for applications in IOT. In this work, we built up optically powered active sensing system, supplying uninterrupted power for the remote active sensors and communication modules. Also, we proposed a novel maximum power point tracking technique for photovoltaic power convertors. In our system, the actual output efficiency greater than 40% within 1W laser power. After 1km fiber transmission and opto-electric power conversion, a stable electric power of 210mW was obtained, which is sufficient for operating an active sensing system.

  12. Fiber Optic Temperature Sensors for Thermal Protection Systems Project

    National Aeronautics and Space Administration — In Phase 1, Intelligent Fiber Optic Systems Corporation (IFOS), in collaboration with North Carolina State University, successfully demonstrated a Fiber Bragg...

  13. ANALYSIS OF OPTICAL FIBER COMMUNICATION SYSTEM USING FREE-SPACE FIBER OPTIC SWITCHES

    OpenAIRE

    Ashutosh Kumar

    2014-01-01

    Optical fiber offers many advantages compared with electric cables, including high bandwidth, low loss, and lightweight, immunity from lightening strikes and the resultant current surges, and no electromagnetic interference. Fiber optic networks such as fiber distributed data interface (FDDI) are widely accepted and supported by the industry as one of the international standards for high-speed local area networks (LAN).Therefore, in this presentation, a novel surface-micro mac...

  14. Development of an optical fiber hydrophone with fiber Bragg grating

    Science.gov (United States)

    Takahashi; Yoshimura; Takahashi; Imamura

    2000-03-01

    A new type of optical fiber hydrophone is constructed with a fiber Bragg grating (FBG) based on the intensity modulation of laser light in an FBG under the influence of sound pressure. The FBG hydrophone shows linearity, with dynamic range about 70 dB. It can measure amplitude and phase of an acoustic field in real time, and operates in a wide range of acoustic frequency, at least from 1 kHz to 3 MHz. No signal distortion is observed in the detected signal. Because of the simplicity in its operating principle and geometry, an FBG hydrophone is expected to be an acoustic sensor of high practicality compared to a conventional optical fiber hydrophone. PMID:10829730

  15. 77 FR 65713 - Certain Optoelectronic Devices for Fiber Optic Communications, Components Thereof, and Products...

    Science.gov (United States)

    2012-10-30

    ...Certain Optoelectronic Devices for Fiber Optic Communications, Components Thereof...certain optoelectronic devices for fiber optic communications, components thereof...certain optoelectronic devices for fiber optic communications, components...

  16. ArF excimer laser microprocessing of polymer optical fibers for photonic sensor applications

    International Nuclear Information System (INIS)

    A study of polymer optical fiber microstructuring by use of deep ultraviolet excimer laser radiation at 193 nm wavelength is performed. The ablation characteristics of the fiber cladding and core materials are analyzed comparatively. The laser irradiation effects are dynamically studied by on-line monitoring of the laser ablation induced waveguiding losses, the latter being correlated with the spatial structuring parameters. The fiber surface is modified to incorporate cavities, which are subsequently employed as sensitive material receptors for the development of customized photonic sensors. The sensing capability of the microstructured plastic optical fibers is demonstrated by ammonia and humidity detection. (paper)

  17. Demonstration of a refractometric sensor based on an optical micro-fiber three-beam interferometer

    Science.gov (United States)

    Han, Chunyang; Ding, Hui; Lv, Fangxing

    2014-12-01

    With diameter close to the wavelength of the guided light and high index contrast between the fiber and the surrounding, an optical micro-fiber shows a variety of interesting waveguiding properties, including widely tailorable optical confinement, strong evanescent fields and waveguide dispersion. Among various micro-fiber applications, optical sensing has been attracting increasing research interest due to its possibilities of realizing miniaturized fiber optic sensors with small footprint, high sensitivity, and low optical power consumption. Typical micro-fiber based sensing structures, including Michelson interferometer, Mach-Zenhder interferometer, Fabry-Perot interferometer, micro-fiber ring resonator, have been proposed. The sensitivity of these structures heavily related to the fraction of evanescent field outside micro-fiber. In this paper, we report the first theoretical and experimental study of a new type of refractometric sensor based on micro-fiber three-beam interferometer. Theoretical and experimental analysis reveals that the sensitivity is not only determined by the fraction of evanescent field outside the micro-fiber but also related to the values of interferometric arms. The sensitivity can be enhanced significantly when the effective lengths of the interferometric arms tends to be equal. We argue that this has great potential for increasing the sensitivity of refractive index detection.

  18. Demonstration of a refractometric sensor based on an optical micro-fiber three-beam interferometer.

    Science.gov (United States)

    Han, Chunyang; Ding, Hui; Lv, Fangxing

    2014-01-01

    With diameter close to the wavelength of the guided light and high index contrast between the fiber and the surrounding, an optical micro-fiber shows a variety of interesting waveguiding properties, including widely tailorable optical confinement, strong evanescent fields and waveguide dispersion. Among various micro-fiber applications, optical sensing has been attracting increasing research interest due to its possibilities of realizing miniaturized fiber optic sensors with small footprint, high sensitivity, and low optical power consumption. Typical micro-fiber based sensing structures, including Michelson interferometer, Mach-Zenhder interferometer, Fabry-Perot interferometer, micro-fiber ring resonator, have been proposed. The sensitivity of these structures heavily related to the fraction of evanescent field outside micro-fiber. In this paper, we report the first theoretical and experimental study of a new type of refractometric sensor based on micro-fiber three-beam interferometer. Theoretical and experimental analysis reveals that the sensitivity is not only determined by the fraction of evanescent field outside the micro-fiber but also related to the values of interferometric arms. The sensitivity can be enhanced significantly when the effective lengths of the interferometric arms tends to be equal. We argue that this has great potential for increasing the sensitivity of refractive index detection. PMID:25511687

  19. Metal-coated optical fiber damage sensors

    Science.gov (United States)

    Chang, Chia-Chen; Sirkis, James S.

    1993-07-01

    A process which uses electroplating methods has been developed to fabricate metal coated optical fiber sensors. The elastic-plastic characteristics of the metal coatings have been exploited to develop a sensor capable of `remembering' low velocity impact damage. These sensors have been investigated under uniaxial tension testing of unembedded sensors and under low velocity impact of graphite/epoxy specimens with embedded sensors using both Michelson and polarimetric optical arrangements. The tests show that coating properties alter the optical fiber sensor performance and that the permanent deformation in the coating can be used to monitor composite delamination/impact damage.

  20. Functional analysis of fiber optic sensors using statistical photon counting: an automobile case study covered from quantum mechanics

    Science.gov (United States)

    Betancur, J. Alejandro

    2012-06-01

    Currently, the applications of fiber optic sensors on the automobile industry are gaining importance due to their potential for implementation in data acquisition and signal transmission. This paper covers from quantum mechanics, the photon counting in optical fibers using coherent states and generalized intelligent states, described by hyper-geometric functions and Bessel functions. Different fiber optic configurations will be showed, in order to show some representative factors that influence the probability of coherent and intelligent photons detected and transmitted by optical fibers. Finally, from the automotive industry, some applications are presented, from which the quantum-optical approach here proposed makes sense.