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1

Fiber-Optic Sensing Technology  

Energy Technology Data Exchange (ETDEWEB)

This article offers a basic review of fiber-optic sensing technology, or more specifically, fiber-optic sensing technology as applied to the qualitative or quantitative identification of a chemical sample, and how it works,

Milnes, M. [Westinghouse Savannah River Company, AIKEN, SC (United States); Baylor, L.C.; Bave, S.

1996-10-24

2

Optical fiber rotation sensing  

CERN Document Server

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

Burns, William K; Kelley, Paul

1993-01-01

3

Ultra small integrated optical fiber sensing system  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 resulti...

2012-01-01

4

Ultra Small Integrated Optical Fiber Sensing System  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 resulti...

2012-01-01

5

Ultra Small Integrated Optical Fiber Sensing System  

Directory of Open Access Journals (Sweden)

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.

Peter Van Daele

2012-09-01

6

Ultra Small Integrated Optical Fiber Sensing System  

Science.gov (United States)

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.

Van Hoe, Bram; Lee, Graham; Bosman, Erwin; Missinne, Jeroen; Kalathimekkad, Sandeep; Maskery, Oliver; Webb, David J.; Sugden, Kate; Van Daele, Peter; Van Steenberge, Geert

2012-01-01

7

Long-distance fiber-optic ?-OTDR intrusion sensing system  

Science.gov (United States)

A novel fiber-optic phase-sensitive optical time-domain reflectometer (?-OTDR) distributed sensing system is proposed and demonstrated for long-distance intrusion monitoring. By using the bi-directional Raman optical amplification technology, even intrusion signal detection along the whole sensing distance of ~62km has been demonstrated, resulting in the longest and the most sensitive ? -OTDR distributed sensing system reported so far, to the best of our knowledge. In addition, high-power single-mode fiber laser with ultra-narrow line-width and special optical fiber cable encapsulated by fiber reinforced plastic (FRP) are used to further enhance the intrusion detection sensitivity, respectively.

Rao, Yun-Jiang; Luo, Jun; Ran, Zeng-Ling; Yue, Jian-Feng; Luo, Xiao-Dong; Zhou, Zhi

2009-10-01

8

Fiber optic-based refractive index sensing at INESC Porto.  

Science.gov (United States)

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 fibers. PMID:22969405

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

2012-01-01

9

Fiber Optic-Based Refractive Index Sensing at INESC Porto  

Directory of Open Access Journals (Sweden)

Full Text Available 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 fibers.

Orlando Frazão

2012-06-01

10

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.

2011-02-01

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Fiber Optic-Based Refractive Index Sensing at INESC Porto  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

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

2012-01-01

12

Photoinduced Electron Transfer Based Ion Sensing within an Optical Fiber  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We combine suspended-core microstructured optical fibers with the photoinduced electron transfer (PET) effect to demonstrate a new type of fluorescent optical fiber-dip sensing platform for small volume ion detection. A sensor design based on a simple model PET-fluoroionophore system and small core microstructured optical fiber capable of detecting sodium ions is demonstrated. The performance of the dip sensor operating in a high sodium concentration regime (925 ppm Na+) and for lower sodium ...

Englich, Florian V.; Tze Cheung Foo; Richardson, Andrew C.; Heike Ebendorff-Heidepriem; Sumby, Christopher J.; Monro, Tanya M.

2011-01-01

13

Transformer partial discharge monitoring based on optical fiber sensing  

Science.gov (United States)

The power transformer is the most important equipment of the high voltage power grid, however, some traditional methods of online partial discharge monitoring have some limitations. Based on many advantages of the optical fiber sensing technology, we have done some research on fiber optics Fabry-Perot (FP) sensing which can be useful for the transformer on online partial discharge monitoring. This research aimed at improving the reliability of power system safety monitoring. We have done some work as follows: designing a set for fiber optics FP sensor preparation, according to the fabrication procedure strictly making out the sensors, building a reasonable signal demodulation system for fiber optics FP sensing, doing a preliminary analysis about online partial discharge signal monitoring, including the research on different discharge intensities with the same measuring distance and different measuring distances with the same discharge intensity, and then making a detailed analysis of the experimental results.

Wang, Kun; Tong, Xinglin; Zhu, Xiaolong

2014-06-01

14

Optical Fiber Sensing Based on Reflection Laser Spectroscopy  

Directory of Open Access Journals (Sweden)

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.

Gianluca Gagliardi

2010-03-01

15

Downhole fiber optic sensing: the oilfield service provider's perspective  

Science.gov (United States)

There is increasing interest in the petroleum industry in the application of fiber-optic sensing techniques. In this paper, we review which sensing technologies are being adopted downhole and the drivers for this deployment. We describe the performance expectations (accuracy, resolution, stability and operational lifetime) that the oil companies and the oil service companies have for fiber-optic sensing systems. We also describe the environmental conditions (high hydrostatic pressures, high temperatures, shock, vibration, crush, and chemical attack) that these systems must tolerate in order to provide reliable and economically attractive reservoir-performance monitoring solutions.

Skinner, Neal G.; Maida, John L., Jr.

2004-12-01

16

Sensing characteristics of birefringent microstructured polymer optical fiber  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We experimentally studied several sensing characteristics of a birefringent microstructured polymer optical fiber. The fiber exhibits a birefringence of the order 2×10-5 at 1.3 ?m because of two small holes adjacent to the core. In this fiber, we measured spectral dependence of phase and group modal birefringence, bending losses, polarimetric sensitivity to strain and temperature. The sensitivity to strain was also examined for intermodal interference observed in the spectral range below 0....

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

2011-01-01

17

Photoinduced electron transfer based ion sensing within an optical fiber.  

Science.gov (United States)

We combine suspended-core microstructured optical fibers with the photoinduced electron transfer (PET) effect to demonstrate a new type of fluorescent optical fiber-dip sensing platform for small volume ion detection. A sensor design based on a simple model PET-fluoroionophore system and small core microstructured optical fiber capable of detecting sodium ions is demonstrated. The performance of the dip sensor operating in a high sodium concentration regime (925 ppm Na(+)) and for lower sodium concentration environments (18.4 ppm Na(+)) is explored and future approaches to improving the sensor's signal stability, sensitivity and selectivity are discussed. PMID:22163712

Englich, Florian V; Foo, Tze Cheung; Richardson, Andrew C; Ebendorff-Heidepriem, Heike; Sumby, Christopher J; Monro, Tanya M

2011-01-01

18

The application of laser micromachining technology in fiber optic sensing  

Science.gov (United States)

Micromachining of optic fiber is one of the key technologies in the field of fiber optic sensing. In this paper, the progress of optic fiber machining has been discussed and our study in this field has been described. Because the main component of fiber optic materials is SiO2 and the optic fibers are thin, small, hard and crisp, the results of micromachining of optic fiber are poor by using traditional methods. It is impossible to do the partial precise modification for optic fibers or make holes on them and therefore it is difficult to meet the needs of practical use. The newly deep ultraviolet light micromachining technology is the effective technology for the micromachining of optic fiber. By using excimer laser, the three-dimensional micromachining of fiber materials has been studied, and the results show that with the increase of the pulse laser energy, the etching width of the fiber grooves will increase and then keep unchanged after the pulse laser energy reaches a certain value. For the two-dimensional micromachining of fiber materials, it was found that the etching was related to the focused spot quality such as energy uniformity, scanning velocity and repetition frequency, which provides theoretical and technical preliminary for the direct micromachining of optic fiber using excimer laser. Fiber Bragg Grating (FBG) sensors are new sensors which developed in recently years and have important application in many fields. FBG is the key sensing element and can be prepared by the precise micro modification of fiber optic materials. In this paper, the study on the micromachining to change precisely the local refractive ratio of optic fiber materials with excimer laser has performed and FBG can be formed in this way. Various kinds of FBG including single mode, multimode, chirp and long period fiber grating have been prepared, and the FBG sensors for the detection of stress/strain, pressure, temperature, vibration have been manufactured and used in many fields such as bridges, petroleum chemistry, industry and civil construction, navigation.

Jiang, Desheng; Xin, Sijin; Wei, Renxuan; Huang, Jun

2004-12-01

19

Multiparameter fiber optic sensing system for monitoring enhanced geothermal systems  

Energy Technology Data Exchange (ETDEWEB)

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.

William A. Challener

2014-12-04

20

Statistical-mode sensor for fiber optic vibration sensing uses.  

Science.gov (United States)

A method of sensing vibration using the detection of changes in the spatial distribution of energy in the output of a multimode optical fiber has been demonstrated. Two implementations of the sensor have been built and tested. The first implementation involved simple optical processing of the output fiber speckle pattern using spatial filtering. The second implementation involved projecting the pattern on a CCD array and digitally processing observed changes in the intensity distribution. A mathematical model has been developed which has shown good agreement with observed sensor behavior. The sensor technique has been used to detect induced structural vibration in laboratory test specimens. Simple field testing has also demonstrated the ability of the technique to detect personnel and vehicles passing over a buried and electrically undetectable sensing cable. The sensing technique is compatible with off-the-shelf components and fiber cable and even allows for simultaneous telecommunication and sensing using the same optical fiber cable. Near term application of this technology could provide significant benefits for vibration sensing, intrusion detection, and acoustic sensing. PMID:20555666

Spillman, W B; Kline, B R; Maurice, L B; Fuhr, P L

1989-08-01

 
 
 
 
21

Fiber optic shape sensing for monitoring of flexible structures  

Science.gov (United States)

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

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

2012-03-01

22

Distributed Fiber Optic Gas Sensing for Harsh Environment  

Energy Technology Data Exchange (ETDEWEB)

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.

Juntao Wu

2008-03-14

23

Melamine sensing based on evanescent field enhanced optical fiber sensor  

Science.gov (United States)

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

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

2013-08-01

24

Extreme temperature sensing using Brillouin scattering in optical fibers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Fellay, Alexandre

2003-01-01

25

Dielectric annular core fiber for optical sensing.  

Czech Academy of Sciences Publication Activity Database

. 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]Grant CEP: GA ?R(CZ) GA102/05/0948Výzkumný zám?r: CEZ:AV0Z2067918Klí?ová slova: fibre optic sensorscapillarityKód oboru RIV: JB - Senzory, ?idla, m??ení a regulace

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

26

RVM Based Compressed Sensing for Optical Fiber Pipeline Data Compression  

Directory of Open Access Journals (Sweden)

Full Text Available Due to long time continuous operation and the high sampling rate, the distributed optical fiber pre-warning system will generate vast amounts of data. Compressed sensing can sample and compress the signal at the same time thus reduce the data amount to be stored or transferred. Therefore, this article uses compressed sensing approach to compress the optical fiber pre-warning data. In compressed sampling phase, the signal is classified using sparse detection method, then more measurements will be taken for the segment containing threatening event than the segment of normal operation, through this the amount of data can be further reduced. In the signal reconstruction phase, the signal compressed sampling process is modeled by the relevant vector machine and the signal recovery is implemented by probabilistic parameter estimation methods. Using Bayesian framework, the sparsity of the signal and the noise each is modeled by a prior. The sparsity and the noise can be estimated in parameter estimation process and the sparsity needn't be given in advance. The optical fiber pre-warning system is long-running system and the sparsity of the signal will change with time, so the automatic sparsity determination ability is superior to other existing recovery methods. Experimental results show that, under the same measurement, the proposed method can reconstruct the signal with high quality and the reconstructed signal will not affect the positioning result.

HongJie Wan

2013-01-01

27

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

Science.gov (United States)

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

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

2013-07-29

28

Enabling aspects of fiber optic acoustic sensing in harsh environments  

Science.gov (United States)

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.

Saxena, Indu F.

2013-05-01

29

High-spatial-resolution fiber optic distributed force sensing with synthesis of optical coherence function  

Science.gov (United States)

Arbitrary characteristics of optical interference have been realized, in our group, by Synthesis of Optical Coherence Function(SOCF) with electrical control and without mechanical scanning. Various applications for optical sensing have been developed by SOCF. Delta function like optical coherence function with higher spatial resolution and higher dynamic range have been achieved by using a broadband tunable super-structure-grating distributed Bragg reflector laser diode (SSG-DBRLD). This time, we improve driving circuit and frequency calibration of the SSG-DBR-LD to achieve a 5THz tunable band width. We apply the characteristics to distributed fiber optic force sensing using polarization maintaining fiber (PMF) as a sensing head. Its principle is polarization mode coupling by the force applied to the fiber. In the experiment, we improve the spatial resolution more than one digit compared with the previous data, and realize 20cm. This technique can be used as a nerve system for smart materials and structures.

Hotate, Kazuo; Makino, Kohji; Ishikawa, Mitsuteru; Yoshikuni, Yuzo

30

Extreme temperature sensing using brillouin scattering in optical fibers  

CERN Document Server

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...

Fellay, Alexandre

31

Fiber optic device for sensing the presence of a gas  

Energy Technology Data Exchange (ETDEWEB)

A fiber-optic device for sensing the presence of a gas in an environment is provided. The device comprises a light source for directing a light beam to a layer system having a first surface and a second surface opposite the first surface. The first surface is exposable to the light beam and the second surface is exposable to the environment. A first light portion encounters and reflects from the first surface at an angle of incidence free from optical wave guide resonance phenomenon and the second light portion encounters and reflects from the first surface at an angle of incidence enabling an optical wave guide resonance phenomenon. The layer system is selected to reversibly react with the gas to be detected. The reaction between the gas and the material changes the material's optical properties and the wavelength at which the optical wave guide resonance occurs. Furthermore, a mechanism for measuring the intensity of the reflected first light portion relative to the reflected second light portion is provided with the ratio of the first and second light portions indicating the concentration of the gas presence in the environment.

Benson, David K. (14154 W. First Dr., Golden, CO 80401); Bechinger, Clemens S. (35 S. Holman Way, # 3D, Golden, CO 80401); Tracy, C. Edwin (19012 W. 60th Dr., Golden, CO 80403)

1998-01-01

32

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

Science.gov (United States)

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.

Fiechtner, Kaitlyn Leann

2010-01-01

33

Magnetic sensing with ferrofluid and fiber optic connectors.  

Science.gov (United States)

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. PMID:24573312

Homa, Daniel; Pickrell, Gary

2014-01-01

34

Perfluorinated Plastic Optical Fiber Tapers for Evanescent Wave Sensing  

Directory of Open Access Journals (Sweden)

Full Text Available In this work we describe the fabrication and the characterization of perfluorinated plastic-cladded optical fiber tapers. The heat-and-pull procedure has been used to fabricate symmetric tapers. Devices with different taper ratio have been produced and the repeatability of the process has been verified. The very low refractive indexes of the core-cladding perfluorinated polymers (n = 1.35–1.34 permit a strong enhancement of the evanescent wave power fraction in aqueous environments (n = 1.33, making them very attractive for evanescent wave sensing. The tapers have been characterized carrying out evanescent field absorbance measurements with different concentrations of methylene blue in water and fluorescence collection measurements in an aqueous solution containing Cy5 dye. A good sensitivity, tightly related to the low refractive index of the core-cladding materials and the geometrical profile, has been shown.

Romeo Bernini

2009-12-01

35

Fiber optic microphone having a pressure sensing reflective membrane and a voltage source for calibration purpose  

Science.gov (United States)

A fiber optic microphone is provided for measuring fluctuating pressures. An optical fiber probe having at least one transmitting fiber for transmitting light to a pressure-sensing membrane and at least one receiving fiber for receiving light reflected from a stretched membrane is provided. The pressure-sensing membrane may be stretched for high frequency response. Further, a reflecting surface of the pressure-sensing membrane may have dimensions which substantially correspond to dimensions of a cross section of the optical fiber probe. Further, the fiber optic microphone can be made of materials for use in high temperature environments, for example greater than 1000 F. A fiber optic probe is also provided with a back plate for damping membrane motion. The back plate further provides a means for on-line calibration of the microphone.

Zuckerwar, Allan J. (inventor); Cuomo, Frank W. (inventor); Robbins, William E. (inventor)

1993-01-01

36

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

Directory of Open Access Journals (Sweden)

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.

Fei Ye

2014-06-01

37

Expanding the realm of fiber optic confocal sensing for probing position, displacement, and velocity  

International Nuclear Information System (INIS)

We describe a fiber optic confocal sensor (FOCOS) system that uses an optical fiber and a lens to accurately detect the position of an object at, or close to, the image plane of the fiber tip. The fiber characteristics (diameter and numerical aperture) and optics (lens F and magnification) define the span and precision of the sensor and may be chosen to fit a desired application of position and displacement sensing. Multiple measurement points (i.e., fiber-tip images) may be achieved by use of multiple wavelengths in the fiber, so that each wavelength images the fiber at a different plane due to the chromatic dispersion of the optics. Further multiplexing may be achieved by adding fibers on the optical axis. A FOCOS with multiplexed fibers and wavelengths may also be used for velocity measurements

2006-10-20

38

Expanding the realm of fiber optic confocal sensing for probing position, displacement, and velocity.  

Science.gov (United States)

We describe a fiber optic confocal sensor (FOCOS) system that uses an optical fiber and a lens to accurately detect the position of an object at, or close to, the image plane of the fiber tip. The fiber characteristics (diameter and numerical aperture) and optics (lens F/# and magnification) define the span and precision of the sensor and may be chosen to fit a desired application of position and displacement sensing. Multiple measurement points (i.e., fiber-tip images) may be achieved by use of multiple wavelengths in the fiber, so that each wavelength images the fiber at a different plane due to the chromatic dispersion of the optics. Further multiplexing may be achieved by adding fibers on the optical axis. A FOCOS with multiplexed fibers and wavelengths may also be used for velocity measurements. PMID:17068508

Shafir, E; Berkovic, G

2006-10-20

39

Integration of nanoporous zeolite with optical fiber devices for chemical sensing  

Science.gov (United States)

Label-free optical fiber chemical sensors have provoked significant research interest in recent years due to their unique advantages of small size, low cost, potential for distributed sensing, capability of in situ and remote operation, and tolerance to harsh environments. However, existing optical fiber chemical sensors lack the desired sensitivity and specificity for many applications such as chemical and biological analysis, industrial process control, environmental monitoring, and national security. The dissertation summarizes our research efforts and results in functional integration of nanoporous zeolites with optical fiber devices for development of label-free optical fiber chemical sensors with high sensitivity and selectivity. Fundamental research has been conducted in nano-materials, micro-devices and the material-device integrations. The material research has been focused on synthesis and characterization of nanoporous zeolites for optical chemical sensing. The research in devices has led to the successful design, fabrication and demonstration of a number of fiber sensor platforms including the turn-around-point long period fiber gratings (TAP-LPFG), the singlemode-multimode- singlemode (SMS) fiber interferometers, the long period fiber grating (LPFG) assisted Michelson interferometers, and nanostructured fiber optic surface enhanced Raman scattering (SERS) probes. Optical fiber chemical sensors have been successfully fabricated by growing zeolite thin films on the fiber devices, and evaluated for their sensitivity, detection limit and selectivity/specificity. The encouraging results reveal that integration of nanoporous zeolite with optical fiber devices presents a promising solution for development of high performance optical chemical sensors.

Lan, Xinwei

40

On-line power transformer partial discharge monitoring based on the optical fiber sensing technology  

Science.gov (United States)

One of the most important equipment in high voltage power grid system is power transformer, however there are still some limitations on traditional methods of online partial discharge monitoring. Considering the advantages of optical fiber sensing technology, in this paper we do some research on fiber optics F-P sensing which can be used in transformer on online partial discharge monitoring. It also contributes to the improvement of the reliability of power system safety monitoring. This paper designs an equipment scheme for fiber optics F-P sensor, strictly fabricates the sensor according to the fabrication procedure. Moreover, we build a reasonable signal demodulation system for fiber optics F-P sensing, doing a preliminary analysis of online partial discharge signal monitoring,Partial discharge online monitoring system including different intensity discharge with a same sensing distance and a same intensity discharge with different sensing distances. Finally we make a detailed analysis of experimental result.

Wang, Kun; Tong, Xinglin; Hu, Jie; Zhu, Xiaolong

2013-09-01

 
 
 
 
41

Measuring artificial recharge with fiber optic distributed temperature sensing.  

Science.gov (United States)

Heat was used as a tracer to measure infiltration rates from a recharge basin. The propagation of diurnal oscillation of surface water temperature into the basin bed was monitored along a transect using Fiber Optic Distributed Temperature Sensing (FODTS). The propagation rate was related to downward specific discharge using standard theory of heat advection and dispersion in saturated porous media. An estimate of the temporal variation of heat propagation was achieved using a wavelet transform to find the phase lag between the surface temperature diurnal oscillation and the correlated oscillation at 0.33 and 0.98 m below the bed surface. The wavelet results compared well to a constant velocity model of thermal advection and dispersion during periods of relatively constant discharge rates. The apparent dispersion of heat was found to be due primarily to hydrodynamic mechanisms rather than thermal diffusion. Specific discharge estimates using the FODTS technique also compared well to water balance estimates over a four month period, although there were occasional deviations that have yet to be adequately explained. The FODTS technique is superior to water balance in that it produces estimates of infiltration rate every meter along the cable transect, every half hour. These high resolution measurements highlighted areas of low infiltration and demonstrated the degradation of basin efficiency due to source waters of high suspended solids. FODTS monitoring promises to be a useful tool for diagnosing basin performance in an era of increasing groundwater demand. PMID:23110559

Becker, Matthew W; Bauer, Brian; Hutchinson, Adam

2013-01-01

42

Characterization of Flexible Copolymer Optical Fibers for Force Sensing Applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 diamete...

Marek Krehel; Rossi, Rene? M.; Gian-Luca Bona; Scherer, Lukas J.

2013-01-01

43

Experimental study of liquid refractive index sensing based on a U-shaped optical fiber  

Science.gov (United States)

A U-shaped optical fiber sensing system designed to measure the refractive index of liquid had been proposed. The sensing mechanism of U-shaped optical fiber was discussed. A general single-mode fiber was bent into U-shaped and partially cladding of U-shaped fiber was corroded by HF acid buffer solution. Powers of different diameters of U-shaped fibers had been measured by many experiments. The results showed that the diameter of U-shaped fiber cladding 40 ?m and the diameter of U-shaped was 1 cm were suitable to measure liquid refractive index. Then, this U-shaped optical fiber was immersed in liquid, such as pure water, ethanol, acetone and isopropanol, respectively. The evanescent field of the U-shaped fiber should be modulated by the liquid. The optical signal in the U-shaped fiber was measured with the optical spectrum analyzers(OSA). Finally, the experimental results were analyzed, and the spectra in the air was selected as a reference. The relative intensity was obtained for the different liquid. These results showed that the relative intensity of the liquid had a good linear relationship. This sensing device could accurately demarcate refractive index of liquid. It is simple, low cost, and it can also be applied in measuring the level of liquid.

Zhang, Zhi; Yan, Haitao; Li, Liben; Wang, Ming

2013-12-01

44

Research on distributed strain separation technology of fiber Brillouin sensing system combining an electric power optical fiber cable  

Science.gov (United States)

Brillouin-based optical fiber sensing system has been taken more and more attentions in power transmission line in recent years. However, there exists a temperature cross sensitivity problem in sensing system. Hence, researching on strain separation technology of fiber brillouin sensing system is an urgent requirement in its practical area. In this paper, a real-time online distributed strain separation calculation technology of fiber Brillouin sensing combining an electric power optical fiber cable is proposed. The technology is mainly composed of the Brillouin temperature-strain distributed measurement system and the Raman temperature distributed measurement system. In this technology, the electric power optical fiber cable is a special optical phase conductor (OPPC); the Brillouin sensing system uses the Brillouin optical time domain analysis (BOTDA) method. The optical unit of the OPPC includes single-mode and multimode fibers which can be used as sensing channel for Brillouin sensing system and Raman sensing system respectively. In the system networking aspect, the data processor of fiber Brillouin sensing system works as the host processor and the data processor of fiber Raman sensing system works as the auxiliary processor. And the auxiliary processor transfers the data to the host processor via the Ethernet interface. In the experiment, the BOTDA monitoring system and the Raman monitoring system work on the same optical unit of the OPPC simultaneously; In the data processing aspect, the auxiliary processor of Raman transfers the temperature data to the host processor of Brillouin via the Ethernet interface, and then the host processor of Brillouin uses the temperature data combining itself strain-temperature data to achieve the high sampling rate and high-precision strain separation via data decoupling calculation. The data decoupling calculation is achieved through the interpolation, filtering, feature point alignment, and the singular point prediction algorithm etc. Testing in the laboratory and the transmission line test base all show that the simultaneous temperature and strain distribution measurement system can work effectively and reliably. This system provides a good solution reference to solve the temperature cross sensitivity problem in Brillouin-based optical fiber sensing system, and demonstrate a great practical value in power system applications.

Lei, Yuqing; Chen, Xi; Li, Jihui; Tong, Jie

2013-12-01

45

Applicability study of optical fiber distribution sensing to nuclear facilities  

Energy Technology Data Exchange (ETDEWEB)

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 {sup 60}Co {gamma} 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 {sup 60}Co {gamma} 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 10{sup 7}[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)

Takada, Eiji; Kimura, Atsushi; Nakazawa, Masaharu [Graduate School of Engineering, University of Tokyo, Tokyo (Japan); Kakuta, Tsunemi

1999-08-01

46

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2013-01-01

47

Application research on hydraulic coke cutting monitoring system based on optical fiber sensing technology  

Science.gov (United States)

With the development of the optical fiber sensing technology, the acoustic emission sensor has become one of the focal research topics. On the basis of studying the traditional hydraulic coke cutting monitoring system, the optical fiber acoustic emission sensor has been applied in the hydraulic coke cutting monitoring system for the first time, researching the monitoring signal of the optical fiber acoustic emission sensor in the system. The actual test results show that using the acoustic emission sensor in the hydraulic coke cutting monitoring system can get the real-time and accurate hydraulic coke cutting state and the effective realization of hydraulic coke cutting automatic monitoring in the Wuhan Branch of Sinopec.

Zhong, Dong; Tong, Xinglin

2014-06-01

48

Optical fiber based sensing system design for the health monitoring of multi-layered pavement structure  

Science.gov (United States)

This paper introduces an optical fiber based sensing system design for multi-layered pavement structural health monitoring. The co-line and integration design of FBG (Fiber Bragg Gating) sensors and BOTDR (Brillouin Optical Time Domain Reflectometry) sensors will ensure the large scale damage monitoring and local high accurate strain measurement. The function of pavement structure multi-scale shape measurement will provide real time subgrade settlement and rutting information. The sensor packaging methodology and strain transfer problem of the system will also be discussed in this paper. Primary lab tests prove the potential and feasibility of the practical application of the sensing system.

Liu, Wanqiu; Wang, Huaping; Zhou, Zhi; Li, Shiyu; Ni, Yuanbao; Wang, Geng

2011-11-01

49

Characterization of flexible copolymer optical fibers for force sensing applications.  

Science.gov (United States)

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

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

2013-01-01

50

Characterization of Flexible Copolymer Optical Fibers for Force Sensing Applications  

Directory of Open Access Journals (Sweden)

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.

Lukas J. Scherer

2013-09-01

51

Optical Fiber Pipeline Data Compression based on Segment Sequential Compressed Sensing  

Directory of Open Access Journals (Sweden)

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.

HongJie Wan

2013-01-01

52

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

Science.gov (United States)

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.

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

2014-04-01

53

High-resolution absolute frequency referenced fiber optic sensor for quasi-static strain sensing  

International Nuclear Information System (INIS)

We present a quasi-static fiber optic strain sensing system capable of resolving signals below nanostrain from 20 mHz. A telecom-grade distributed feedback CW diode laser is locked to a fiber Fabry-Perot sensor, transferring the detected signals onto the laser. An H13C14N absorption line is then used as a frequency reference to extract accurate low-frequency strain signals from the locked system.

2010-07-20

54

High-resolution absolute frequency referenced fiber optic sensor for quasi-static strain sensing.  

Science.gov (United States)

We present a quasi-static fiber optic strain sensing system capable of resolving signals below nanostrain from 20 mHz. A telecom-grade distributed feedback CW diode laser is locked to a fiber Fabry-Perot sensor, transferring the detected signals onto the laser. An H(13)C(14)N absorption line is then used as a frequency reference to extract accurate low-frequency strain signals from the locked system. PMID:20648185

Lam, Timothy T-Y; Chow, Jong H; Shaddock, Daniel A; Littler, Ian C M; Gagliardi, Gianluca; Gray, Malcolm B; McClelland, David E

2010-07-20

55

High-resolution absolute frequency referenced fiber optic sensor for quasi-static strain sensing  

Energy Technology Data Exchange (ETDEWEB)

We present a quasi-static fiber optic strain sensing system capable of resolving signals below nanostrain from 20 mHz. A telecom-grade distributed feedback CW diode laser is locked to a fiber Fabry-Perot sensor, transferring the detected signals onto the laser. An H{sup 13}C{sup 14}N absorption line is then used as a frequency reference to extract accurate low-frequency strain signals from the locked system.

Lam, Timothy T.-Y.; Chow, Jong H.; Shaddock, Daniel A.; Littler, Ian C. M.; Gagliardi, Gianluca; Gray, Malcolm B.; McClelland, David E.

2010-07-20

56

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

Science.gov (United States)

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.

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

2013-12-01

57

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)

2012-11-01

58

Shear stress sensing with Bragg grating-based sensors in microstructured optical fibers.  

Science.gov (United States)

We demonstrate shear stress sensing with a Bragg grating-based microstructured optical fiber sensor embedded in a single lap adhesive joint. We achieved an unprecedented shear stress sensitivity of 59.8 pm/MPa when the joint is loaded in tension. This corresponds to a shear strain sensitivity of 0.01 pm/µ?. We verified these results with 2D and 3D finite element modeling. A comparative FEM study with conventional highly birefringent side-hole and bow-tie fibers shows that our dedicated fiber design yields a fourfold sensitivity improvement. PMID:24105585

Sulejmani, Sanne; Sonnenfeld, Camille; Geernaert, Thomas; Luyckx, Geert; Van Hemelrijck, Danny; Mergo, Pawel; Urbanczyk, Waclaw; Chah, Karima; Caucheteur, Christophe; Mégret, Patrice; Thienpont, Hugo; Berghmans, Francis

2013-08-26

59

A new optical fiber sensor for multipoint radiation measurement with sensing regions in its cladding  

International Nuclear Information System (INIS)

Current scintillating optical fibers for radiation measurement have drawbacks as high intrinsic and radiation-induced loss. In order to overcome these problems, a new optical fiber sensor for multi-point radiation measurements has been proposed with sensing regions in its cladding and in the area outside of the core. A part of the scintillation photons is trapped inside the fiber core and is transmitted to the end. The time of flight technique has been applied to the arrival time difference of the photons which are transmitted to each fiber end. Discrete radiation measurements were possible with a time resolution of 3nsec. Linearity of the measured counts has been demonstrated in a dose rate ranging between 4.2?Sv and 44?Sv. (author)

2004-04-01

60

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

Science.gov (United States)

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.

Duckworth, Gregory L.; Ku, Emery M.

2013-06-01

 
 
 
 
61

Characterization of time-resolved fluorescence response measurements for distributed optical-fiber sensing.  

Science.gov (United States)

A distributed optical-fiber sensing system based on pulsed excitation and time-gated photon counting has been used to locate a fluorescent region along the fiber. The complex Alq3 and the infrared dye IR-125 were examined with 405 and 780 nm excitation, respectively. A model to characterize the response of the distributed fluorescence sensor to a Gaussian input pulse was developed and tested. Analysis of the Alq3 fluorescent response confirmed the validity of the model and enabled the fluorescence lifetime to be determined. The intrinsic lifetime obtained (18.2±0.9 ns) is in good agreement with published data. The decay rate was found to be proportional to concentration, which is indicative of collisional deactivation. The model allows the spatial resolution of a distributed sensing system to be improved for fluorophores with lifetimes that are longer than the resolution of the sensing system. PMID:21102661

Sinchenko, Elena; Gibbs, W E Keith; Davis, Claire E; Stoddart, Paul R

2010-11-20

62

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Chuji Wang

2009-01-01

63

Vibration pattern recognition and classification in OTDR based distributed optical-fiber vibration sensing system  

Science.gov (United States)

In this paper we propose and demonstrate the scheme of vibration pattern recognition and classification in the OTDR based distributed optical-fiber vibration sensing system. We set up the engineering system with signal processing PC for perimeter security in some high-tech park in Nanjing. Three types of disturbing actions, including climbing up and kicking at the wall by a person, and watering on the sensing optical fiber cable same as the rain falling on, are implemented. By using level crossing rate (LCR), we can obtain their individual pattern features, so that the eigenvalue database for three disturbing actions can be built in the system. By comparing three types of vibrations, the differences among these can be given out. The results show three vibration patterns can be recognized and classified effectively.

Zhu, Hui; Pan, Chao; Sun, Xiaohan

2014-03-01

64

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

Science.gov (United States)

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

Gan, Weibing; Zhang, Cui

2013-09-01

65

Thermal-resistant radiation sensing system using optical fiber for monitoring progress of chemical decontamination  

International Nuclear Information System (INIS)

A thermal-resistant radiation sensing system using optical fiber has been developed. The system is for monitoring progress of chemical decontamination and able to measure the gamma-ray level in a hot solution of decontamination chemicals in situ. Our sensor head makes use of thermal-resistant NaI (T1) and it is connected to an optical fiber bundle. Scintillation photons pass from the NaI (T1) into the end of the bundle. This part of the system can withstand temperatures of over 100degC. At the far end of the optical fiber bundle, the scintillation photons are converted into fluorescent photons using a wavelength-shifting fiber. These photons are transferred to a distant photomultiplier tube through two thin transparent optical fibers. Furthermore, we propose a self-compensation technique for the dependence of scintillator sensitivity on. This compensation method is based on the correlation between temperature, sensitivity, and scintillation decay time. We have confirmed that it enables precise measurement of gamma-ray level without temperature-related variations. Finally, we have applied this system to a real project and can confirm its utility in monitoring progress of decontamination. It is able to provide the approximate decontamination factor (D.F.) and predict the dose rate after decontamination. (author)

1999-04-19

66

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

Science.gov (United States)

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

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

2008-12-01

67

Vibration waveform reproduction and location of OTDR based distributed optical-fiber vibration sensing system  

Science.gov (United States)

In this paper, the scheme for both reproducing vibration waveform and locating disturbed places in the OTDR based distributed optical fiber vibration sensing systems is proposed and demonstrated. Based on the sampling law, the vibration waveform is reproduced from the detecting pulses including original sensing signals by denoising selectively, adjusting bias voltage and band-pass filtering. The vibrations at the frequencies of 500Hz and 1000Hz have been experimentally located and reproduced, respectively, and the highest frequency of 1 kHz for reproducing vibration waveform is realized at the repeat frequency of 2 kHz for the laser.

Zhu, Hui; Pan, Chao; Sun, Xiaohan

2013-12-01

68

An optical fiber sensor for remote pH sensing and imaging.  

Science.gov (United States)

A fiber-optical probe for pH sensing and real-time imaging is successfully fabricated by connecting a polymer imaging fiber and a gradient index (GRIN) lens rod which was modified with a sensing film. By employing an improved metallographic microscope, an optical system is designed to cooperate with the probe. This novel technique has high-quality imaging capabilities for observing remote samples while measuring pH. The linear range of the probe is pH 1.2-3.5. This technique overcomes the difficulty that high-quality images cannot be obtained when directly using conventional imaging bundles for pH sensing and imaging. As preliminary applications, the corrosion behavior of an iron screw and the reaction process of rust were investigated in buffer solutions of pH 2.0 and 2.9, respectively. The experiment demonstrated that the pH values of the analytes' surface were higher than that of buffer solutions due to the chemical reaction. It provides great potential for applications in optical multifunctional detection, especially in chemical sensing and biosensing. PMID:22449307

Wang, Jian; Wang, Lili

2012-03-01

69

Spectroscopic and fiber optic ethanol sensing properties Gd doped ZnO nanoparticles.  

Science.gov (United States)

We report the structural, optical and gas sensing properties of prepared pure and Gd doped ZnO nanoparticles through solgel method at moderate temperature. Structural studies are carried out by X-ray diffraction method confirms hexagonal wurtzite structure and doping induced changes in lattice parameters is observed. Optical absorption spectral studies shows red shift in the absorption peak corresponds to band-gap from 3.42eV to 3.05eV and broad absorption in the visible range after Gd doping is observed. Scanning electron microscopic studies shows increase in particle size where the particle diameters increase from few nm to micrometers after Gd doping. The clad modified ethanol fiber-optic sensor studies for ethanol sensing exhibits best sensitivity for the 3% Gd doped ZnO nanoparticles and the sensitivity get lowered incase of higher percentage of Gd doped ZnO sample. PMID:24892544

Noel, J L; Udayabhaskar, R; Renganathan, B; Muthu Mariappan, S; Sastikumar, D; Karthikeyan, B

2014-11-11

70

Spectroscopic and fiber optic ethanol sensing properties Gd doped ZnO nanoparticles  

Science.gov (United States)

We report the structural, optical and gas sensing properties of prepared pure and Gd doped ZnO nanoparticles through solgel method at moderate temperature. Structural studies are carried out by X-ray diffraction method confirms hexagonal wurtzite structure and doping induced changes in lattice parameters is observed. Optical absorption spectral studies shows red shift in the absorption peak corresponds to band-gap from 3.42 eV to 3.05 eV and broad absorption in the visible range after Gd doping is observed. Scanning electron microscopic studies shows increase in particle size where the particle diameters increase from few nm to micrometers after Gd doping. The clad modified ethanol fiber-optic sensor studies for ethanol sensing exhibits best sensitivity for the 3% Gd doped ZnO nanoparticles and the sensitivity get lowered incase of higher percentage of Gd doped ZnO sample.

Noel, J. L.; Udayabhaskar, R.; Renganathan, B.; Muthu Mariappan, S.; Sastikumar, D.; Karthikeyan, B.

2014-11-01

71

FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS  

Energy Technology Data Exchange (ETDEWEB)

A reflection mode fiber optic oxygen sensor is being developed that can operate at high temperatures for power plant applications. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Two critical materials issues are the cluster's ability to withstand high temperatures when immobilized in a porous the sol-gel support, and whether after heating to high temperatures, the sol-gel matrix maintains a high and constant permeability to oxygen to support rapid quenching of luminescence. We used a composite materials approach to prepare stable sensing layers on optical fibers. We dispersed 60 w/w% of a pre-cured sol-gel composite containing the potassium salt of molybdenum clusters (K{sub 2}Mo{sub 6}Cl{sub 14}) into a sol-gel binder solution, and established the conditions necessary for deposition of sol-gel films on optical fibers and planar substrates. The fiber sensor has an output signal of 5 nW when pumped with an inexpensive commercial 365 nm ultraviolet light emitting diode (LED). Quenching of the sensor signal by oxygen was observed up to a gas temperature of 175 C with no degradation of the oxygen permeability of the composite after high temperature cycling. On planar substrates the cluster containing composite responds within <1 second to a gas exchange from nitrogen to oxygen, indicating the feasibility of real-time oxygen detection.

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

2005-07-01

72

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

Science.gov (United States)

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

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

2014-02-01

73

Novel method for improving the space resolution of distributed optical fiber temperature sensing system using decoupling technique  

Science.gov (United States)

The distributed optical fiber temperature sensing system based on the Raman back scattering has been widely used. By using the optical time domain reflection (OTDR) technique, the high intensity light pulse is coupled into optical fiber. By detecting and recording the variation of back scattering signal related to optical fiber temperature along with the time, the distribution measurement of environmental temperature is carried out. In order to ensure a certain intensity of the light pulse, it must have a certain width. In the meanwhile, the responding rate of the photoelectric components and the bandwidth of the digital collection systems cause the reduction of the space resolution. The signal coupling brought by the pulse width can be reduced and the space resolution of distributed optical fiber temperature sensing system can be improved by using self-adaptive wavelet nerve network which has a stronger ability of function approach and tolerant fault to process the data.

Hou, Peiguo; Zheng, Longjiang; Wang, Litian; Wang, Yutian

2000-10-01

74

Integrated guided wave generation and sensing using a single laser source and optical fibers  

International Nuclear Information System (INIS)

This study proposes an integrated lead zirconate titanate/fiber Bragg grating (PZT/FBG) system that can generate and measure guided waves for structural health monitoring (SHM) using a common laser source and optical cables. Among various SHM devices used for guided wave generation and sensing, PZT transducers and FBG sensors have been widely used because of their light weight, non-intrusive nature and compactness. To take the best advantage of the merits of these SHM devices, a combination of PZT-based guided wave generation and FBG-based sensing has been attempted by some researchers. However, the existing hybrid approaches have two independent systems: a wave generation system using electrical devices and a sensing system with optical devices. We have developed a fully integrated PZT/FBG system that uses a single laser source and optical cables. This system can alleviate problems associated with conventional electrical cables, such as electromagnetic interference, signal attenuation and vulnerability to noise. A tunable laser, the common power source for guided wave generation and sensing, is modulated and amplified to excite PZT. This laser is also used with FBG sensors for measuring high-speed strain changes induced by guided waves. The feasibility of this system has been experimentally demonstrated using an aluminum plate

2010-10-01

75

An implantable neural sensing microsystem with fiber-optic data transmission and power delivery.  

Science.gov (United States)

We have developed a prototype cortical neural sensing microsystem for brain implantable neuroengineering applications. Its key feature is that both the transmission of broadband, multichannel neural data and power required for the embedded microelectronics are provided by optical fiber access. The fiber-optic system is aimed at enabling neural recording from rodents and primates by converting cortical signals to a digital stream of infrared light pulses. In the full microsystem whose performance is summarized in this paper, an analog-to-digital converter and a low power digital controller IC have been integrated with a low threshold, semiconductor laser to extract the digitized neural signals optically from the implantable unit. The microsystem also acquires electrical power and synchronization clocks via optical fibers from an external laser by using a highly efficient photovoltaic cell on board. The implantable unit employs a flexible polymer substrate to integrate analog and digital microelectronics and on-chip optoelectronic components, while adapting to the anatomical and physiological constraints of the environment. A low power analog CMOS chip, which includes preamplifier and multiplexing circuitry, is directly flip-chip bonded to the microelectrode array to form the cortical neurosensor device. PMID:23666130

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

2013-01-01

76

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

Directory of Open Access Journals (Sweden)

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

Yoon-Kyu Song

2013-05-01

77

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)

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.

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

2007-07-03

78

Design and Fabrication of Fiber-Optic Nanoprobes for Optical Sensing  

Directory of Open Access Journals (Sweden)

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.

Zhang Yan

2011-01-01

79

Fiber optic vibration sensor  

Energy Technology Data Exchange (ETDEWEB)

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

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

1995-01-01

80

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

Science.gov (United States)

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

Dong, Saying; Liao, Yanbiao; Tian, Qian

2005-10-01

 
 
 
 
81

Monitoring of the ground settlement during a tunnel excavation using 4D optical fiber sensing system  

Science.gov (United States)

In this paper we present an engineering application of optical fiber distributed sensing for monitoring of the ground settlement during a tunnel excavation. The design, installation methods, and implementation of 4D (space plus time) warning system are outlined. The ground settlement was closely monitored for entire 6 months of tunnel construction process, revealing a wide range of geomechanical phenomena. Obtained on-line vertical displacements allowed engineers to control the excavation speed and monitor ground settlement, contributing substantially to the overall reliability and safety.

Guzik, Artur; Yokoyama, Mitsunori; Matsuda, Kimihiko; Kishida, Kinzo

2013-05-01

82

A novel microbending hetero-core fiber optic sensor for force and location sensing with applications to home security  

Science.gov (United States)

In this paper, a novel design of microbending hetero-core fiber optic sensor for force and location sensing is proposed, and potential applications to home security systems are discussed. Force and location detection is done by using two different microbending fiber optic sensors. The main idea is, we have two unknowns, two different fibers, and two simultaneous intensity measurements. In order to demonstrate the location detection of the microbending fiber optic sensor, changes in the light intensity are examined with different force locations and forces magnitudes on the microbending fiber optic sensor. Several experiments are performed for different microbend sensors by varying periodicity, corrugation size, thickness of plates, and the configuration of optical fiber type. All experiments were done on a microbending sensor constructed from 62,5/125 ?m multimode fibers and a microbending sensor constructed from 62,5-50-62,5/125 ?m hetero-core fiber. For each case, the output light intensity is measured as a function of applied force. The characteristics of hysteresis, repeatability and location comparison are examined for each combination of microbending fiber optic sensors. Experimental results show that the sensitivity of the proposed microbending sensor constructed using hetero-core optical fiber having loops is the highest.

Likoglu, Sumeyra; Alemdar, Kubra; Fidanboylu, Kemal; Toker, Onur

2014-03-01

83

Optic fiber sensor-based smart bridge cable with functionality of self-sensing  

Science.gov (United States)

Bridge cables, characterized by distributed large span, serving in harsh environment and vulnerability to random damage, are the key load-sustaining components of cable-based bridges. To ensure the safety of the bridge structure, it is critical to monitor the loading conditions of these cables under lengthwise random damages. Aiming at obtaining accurate monitoring at the critical points as well as the general information of the cable force distributed along the entire cable, this paper presents a study on cable force monitoring by combining optical fiber Bragg grating (FBG) sensors and Brillouin optical time domain analysis/reflectory (BOTDA/R) sensing technique in one single optical fiber. A smart FRP-OF-FBG rebar based cable was fabricated by protruding a FRP packaged OF-FBG sensor into the bridge cable. And its sensing characteristics, stability under high stress state temperature self-compensation as well as BOTDA/R distributed data improvement by local FBG sensors have been investigated. The results show that FRP-OF-FBG rebar in the smart cable can deform consistantly along with the steel wire and the cable force obtained from the optical fiber sensors agree well with theoretical value with relative error less than ±5%. Besides, the temperature self-compensation method provides a significant cost-effective technique for the FRP-OF-FBG based cables' in situ cable force measurement. And furthermore, potential damages of the bridge cable, e.g. wire breaking and corrosion, can be characterized and symbolized by the discontinuity and fluctuation of the distributed BOTDA data thereafter accuracy improved by local FBG sensors.

He, Jianping; Zhou, Zhi; Jinping, Ou

2013-02-01

84

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.

85

Dialysis-assisted fiber optic spectroscopy for in situ biomedical sensing  

Science.gov (United States)

A miniature fiber optic spectrometer enclosed within a semipermeable (dialysis) membrane is proposed for in vivo interstitial sensing applications. The semipermeable membrane acts as a molecular filter, allowing only small molecules to pass through to the sampling volume. This filtering, in principle, should enable continuous in vivo drug sensing, removing the necessity for complex microdialysis systems. We use a biological phantom to examine the reliable detection of a fluorescence signal from small dye molecules in the presence of large fluorophores and scatterers. We find that spectral artefacts arising from scatterers and large fluorophores are substantially suppressed, simplifying the spectral analysis. In addition, the measured sampling rate of 157 s is superior to existing in vivo tissue assaying techniques such as microdialysis, which can take tens of minutes.

Blazkiewicz, Paul P.; Blazkiewicz, K. L.; Verhaege, A.; Anissimov, Y. G.; Roberts, M. S.; Zvyagin, Andrei V.

2006-01-01

86

Optical Fiber Networks for Remote Fiber Optic Sensors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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, ...

Montserrat Fernandez-Vallejo; Manuel Lopez-Amo

2012-01-01

87

Continuous monitoring of plant growth using fiber-optic interferrometric sensing  

Science.gov (United States)

Dendrometers, dendrographs and dry weight measurements have been successfully used for measurements of plant growth. These sensors have been used with Linear Variable Differential Transformer (LVDT) based data logging systems for continuous monitoring. In this paper the preliminary results for a prototype technique is presented as a proof of concept for the continuous monitoring of plant growth using an approach based on fiber-optic interferrometric sensing. The advantage of this sensing technique over the others is the ability to measure and analyze with very high sensitivities such as micron changes in dimensions allowing measurements over short time spans. The sensor was mounted on a Dracaena Sanderiana (Lucky Bamboo) shoot and the change in shoot length dimensions resulted in changes in the output signal display which is in the form of interferrometric fringes. The data acquisition is performed over a long duration using labVIEW based data logging. Filtered output of the data has been presented where an attempt has been made to relate the fringes to length changes. The sensing system is nondestructive and noninvasive and has been targeted to respond to changes in stem length due to changes in plant growth parameters. The objective is to provide a measurement system to do research in optimizing plant growth in greatly reduced time spans. This form of sensing application is also applicable for monitoring the growth of plants growing at much slower rates.

Chatterjee, Julius; Grossman, Barry G.

2011-05-01

88

Fiber-Optic Sensor with Simultaneous Temperature, Pressure, and Chemical Sensing Capabilities  

Energy Technology Data Exchange (ETDEWEB)

This project aimed to develop a multifunctional sensor suitable for process control application in chemical and petrochemical industries. Specifically, the objective was to demonstrate a fiber optic sensing system capable of simultaneous temperature, pressure, and chemical composition determinations based on a single strand of sapphire optical fiber. These capabilities were to be achieved through the incorporation of a phosphor and a Bragg grating into the fiber, as well as the exploitation of the evanescent field interaction of the optical radiation inside the fiber with the surrounding chemical medium. The integration of the three functions into a single probe, compared to having three separate probes, would not only substantially reduce the cost of the combined system, but would also minimize the intrusion into the reactor. Such a device can potentially increase the energy efficiency in the manufacture of chemical and petrochemical products, as well as reduce waste and lead to improved quality. In accordance with the proposed research plan, the individual temperature, pressure and chemical sensors where fabricated and characterized first. Then towards the end of the program, an integrated system was implemented. The sapphire fibers were grown on a laser heated pedestal growth system. The temperature sensor was based on the fluorescence decay principle, which exploits the temperature dependence of the fluorescence decay rate of the selected phosphor. For this project, Cr3+ was chosen as the phosphor, and it was incorporated into the sapphire fiber by coating a short length of the source rod with a thin layer of Cr2O3. After the viability of the technique was established and the growth parameters optimized, the temperature sensor was characterized up to 300 ?C and its long term stability was verified. The chemical sensor determined the concentration of chemicals through evanescent field absorption. Techniques to increase the sensitivity of the evanescent field interaction such as tapering and coiling the fiber were successfully demonstrated. It was shown that the sensor is capable of quantitative measurements in both the mid-infrared and the near infrared regions of the spectrum. For the pressure sensor, a novel concept involving a pressure amplifier was investigated. While the basic idea was found to work, technical difficulties prevented the demonstration of a sensor capable of quantitative pressure measurements. As a result, the final combined probe contained only a temperature sensor and a chemical sensor. Under this program not only was the technical feasibility of a dual temperature/chemical sensor demonstrated, so were those of two ancillary devices. The first is a scan-and-dwell fiber optic mid-IR spectrometer specifically designed for process control applications. Also, a versatile high-brightness fiber optic light source with interchangeable emitting elements to cover different spectral regions has been demonstrated. The commercial potentials of the complete system as well as the individual components are being actively explored now.

Kennedy, Jermaine L

2009-03-12

89

Improved distributed fiber optic sensing system based on single-ended double-pulse input Brillouin scattering  

Science.gov (United States)

In a new distributed fiber optic sensing system, single-ended double-pulse input is used to strengthen Brillouin backscattered light by increasing the population of acoustic phonons. The first pulse (pump pulse), has a wide pulsewidth (tens or hundreds of us) and is used to generate a nonlinear population of acoustic phonons in the sensing fiber. Whereas the second pulse (probe pulse) has a different central wavelength and a much narrower pulse-width (several ns), and is emitted into the sensing fiber with a controlled time delay to absorb the generated abundant acoustic phonons, so that strong Anti-Stokes light can be generated. In this way, Brillouin backscattered light can be detected easily, leading to higher signal to noise ratio and better spatial resolution (less than 1 m), as well as good temperature and strain resolution, and longer sensing distance.

Chang, Tianying; Yang, Ruijuan; Wang, Yongliang; Li, David Y.; Jia, Lei; Cui, Hong-Liang

2014-03-01

90

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ÃŽÂ...

Bassam Alfeeli; Gary Pickrell; Garland, Marc A.; Anbo Wang

2007-01-01

91

Integrated analysis combining microseismic mapping and fiber-optic distributed temperature sensing (DTS)  

Energy Technology Data Exchange (ETDEWEB)

Microseismic mapping has been used for decades to better understand the propagation of fracture networks created during hydraulic fracturing treatments. The ability to accurately evaluate the geometry of a hydraulic fracture treatment and the points of fracture initiation at the near-wellbore provides valuable information. However, accurate production data must be available for each individual stage. Fiber-optic-based distributed temperature sensing (DTS) is a newer technology that provides almost immediate updates of the near-wellbore temperature distribution in one-meter intervals. The benefits of running microseismic mapping and fiber-optic DTS projects as individual diagnostic tools were discussed. The paper showed that the benefits gained from running these tools simultaneously outweighs the benefits of each diagnostic tool on its own. The combination of microseismic information, accurate near-wellbore fluid-travel information from DTS, and accurate production results provides a much better understanding of completion effectiveness by quantifying production rates from each perforation interval, crossflow rate while shut-in, and fluid types recovered from each perforation interval. This paper focused on 3 aspects of combining microseismic mapping with DTS, notably the real-time aspect; the use of both tools to perform more accurate post-fracture analysis; and combining these diagnostic tools with production analysis acquired to temperature data analysis. 9 refs., 12 figs.

Holley, E.H.; Zimmer, U.; Mayerhofer, M.J.; Samson, E. [Pinnacle Technologies, Calgary, AB (Canada)

2010-07-01

92

Research on fully distributed optical fiber sensing security system localization algorithm  

Science.gov (United States)

A new fully distributed optical fiber sensing and location technology based on the Mach-Zehnder interferometers is studied. In this security system, a new climbing point locating algorithm based on short-time average zero-crossing rate is presented. By calculating the zero-crossing rates of the multiple grouped data separately, it not only utilizes the advantages of the frequency analysis method to determine the most effective data group more accurately, but also meets the requirement of the real-time monitoring system. Supplemented with short-term energy calculation group signal, the most effective data group can be quickly picked out. Finally, the accurate location of the climbing point can be effectively achieved through the cross-correlation localization algorithm. The experimental results show that the proposed algorithm can realize the accurate location of the climbing point and meanwhile the outside interference noise of the non-climbing behavior can be effectively filtered out.

Wu, Xu; Hou, Jiacheng; Liu, Kun; Liu, Tiegen

2013-12-01

93

Calibrating Single-Ended Fiber-Optic Raman Spectra Distributed Temperature Sensing Data  

Directory of Open Access Journals (Sweden)

Full Text Available Hydrologic research is a very demanding application of fiber-optic distributed temperature sensing (DTS in terms of precision, accuracy and calibration. The physics behind the most frequently used DTS instruments are considered as they apply to four calibration methods for single-ended DTS installations. The new methods presented are more accurate than the instrument-calibrated data, achieving accuracies on the order of tenths of a degree root mean square error (RMSE and mean bias. Effects of localized non-uniformities that violate the assumptions of single-ended calibration data are explored and quantified. Experimental design considerations such as selection of integration times or selection of the length of the reference sections are discussed, and the impacts of these considerations on calibrated temperatures are explored in two case studies.

Nick van de Giesen

2011-11-01

94

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

Directory of Open Access Journals (Sweden)

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

C. A. Keller

2010-06-01

95

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

Directory of Open Access Journals (Sweden)

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

C. A. Keller

2011-02-01

96

Hollow-core photonic crystal fiber based multifunctional optical system for trapping, position sensing, and detection of fluorescent particles.  

Science.gov (United States)

We demonstrate a novel multifunctional optical system that is capable of trapping, imaging, position sensing, and fluorescence detection of micrometer-sized fluorescent test particles using hollow-core photonic crystal fiber (HC-PCF). This multifunctional optical system for trapping, position sensing, and fluorescent detection is designed such that a near-IR laser light is used to create an optical trap across a liquid-filled HC-PCF, and a 473 nm laser is employed as a source for fluorescence excitation. This proposed system and the obtained results are expected to significantly enable an efficient integrated trapping platform employing HC-PCF for diagnostic biomedical applications. PMID:22627511

Shinoj, V K; Murukeshan, V M

2012-05-15

97

PetroSense{reg_sign} CMS 5000, a fiber optic chemical sensing system for leak detection  

Energy Technology Data Exchange (ETDEWEB)

The PetroSense{reg_sign} CMS 5000 is a continuous monitoring system for the monitoring to total hydrocarbons. It is capable of providing real time, in-situ monitoring of hydrocarbons in water, vapor, soil and water/vapor interface. To monitor leaks for storage tanks the PetroSense{reg_sign} probes have to be placed under or around these tanks. In this paper the performance of the CMS 5000 probes under simulated field conditions will be described along with data from a field installation.

Saini, D.P.; Leclerc, R.; Himka, R.L.; Arman, H. [FCI Environmental Inc., Las Vegas, NV (United States)

1995-12-31

98

Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants  

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-09-30

99

Fiber optic Surface Plasmon Resonance sensor based on wavelength modulation for hydrogen sensing:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A new design of a fiber optic Surface Plasmon Resonance (SPR) sensor using Palladium as a sensitive layer for hydrogen detection is presented. In this approach, a transducer layer is deposited on the outside of a multimode fiber, after removing the optical cladding. The transducer layer is a multilayer stack made of a Silver, a Silica and a Palladium layer. The spectral modulation of the light transmitted by the fiber allows to detect the presence of hydrogen in the environment. The sensor is...

Perrotton, C.; Javahiraly, N.; Slaman, M. J.; Dam, B.; Meyrueis, P.

2011-01-01

100

Vibration sensing in flexible structures using a distributed-effect modal domain optical fiber sensor  

Science.gov (United States)

Modal domain optical fiber sensors have recently been employed in the implementation of system identification algorithms and the closed-loop control of vibrations in flexible structures. The mathematical model of the modal domain optical fiber sensor used in these applications, however, only accounted for the effects of strain in the direction of the fiber's longitudinal axis. In this paper, we extend this model to include the effects of arbitrary stress. Using this sensor model, we characterize the sensor's sensitivity and dynamic range.

Reichard, Karl M.; Lindner, Douglas K.; Claus, Richard O.

1991-01-01

 
 
 
 
101

Fiber Optic Microphone  

Science.gov (United States)

Research into advanced pressure sensors using fiber-optic technology is aimed at developing compact size microphones. Fiber optic sensors are inherently immune to electromagnetic noise, and are very sensitive, light weight, and highly flexible. In FY 98, NASA researchers successfully designed and assembled a prototype fiber-optic microphone. The sensing technique employed was fiber optic Fabry-Perot interferometry. The sensing head is composed of an optical fiber terminated in a miniature ferrule with a thin, silicon-microfabricated diaphragm mounted on it. The optical fiber is a single mode fiber with a core diameter of 8 micron, with the cleaved end positioned 50 micron from the diaphragm surface. The diaphragm is made up of a 0.2 micron thick silicon nitride membrane whose inner surface is metallized with layers of 30 nm titanium, 30 nm platinum, and 0.2 micron gold for efficient reflection. The active sensing area is approximately 1.5 mm in diameter. The measured differential pressure tolerance of this diaphragm is more than 1 bar, yielding a dynamic range of more than 100 dB.

Cho, Y. C.; George, Thomas; Norvig, Peter (Technical Monitor)

1999-01-01

102

Integrated fiber optic sensing system for in-situ characterization of the curing process of thermoset-based composites  

Science.gov (United States)

In the last decade, in light of their superior mechanical properties advanced polymer matrix composites have been indicated as the most suitable candidates as Smart Materials and Structures. However, their final properties are strongly dependent on the processing stage and key points to improve the quality and the reliability of these materials that have been identified in the cure monitoring and the optimization of the manufacturing process. Based on this line of argument, an integrated fiber optic sensing system for simultaneous refractive index and temperature measurements has been designed and developed in order to monitor the curing process of thermoset based composites. A fiber optic refractometer has been designed by using the free end of the sensing optical fiber. A theoretical model has been developed for converting refractive index changes in detailed information on the extent of the curing. Its validation has been proved by comparison with calorimetric characterization. In addition, integrated fiber Bragg gratings has been used for local temperature measurements. The interrogation of the sensing Bragg grating has been implemented by using a different fiber Bragg grating able to convert the resonance wavelength shift in intensity changes. Preliminary results are presented.

Cusano, Andrea; Salvarezza, P.; Breglio, Giovanni; Cutolo, Antonello; Calabro, Antonio M.; Giordano, Michele; De Nicola, Sergio; Nicolais, Luigi

2001-08-01

103

Fiber optic lifetime pH sensing based on ruthenium(II) complexes with dicarboxybipyridine  

International Nuclear Information System (INIS)

The complexes of ruthenium(II) with phenanthroline (Phen), diphenylphenanthroline (Ph2Phen) and with 4,4'-dicarboxy-2,2'-bipyridine acid (Dcbpy) ([Ru(Phen)2Dcbpy]Cl2 and [Ru(Ph2Phen)2Dcbpy]Cl2) were synthesized and the variation of the correspondent fluorescence intensity and lifetime with the pH characterized. Luminescence intensity, emission wavelength and excited state lifetime all show a typical sigmoid variation with pH in the range 3-9, demonstrating the suitability of this complex for luminescence sensing applications. In aqueous solutions (28% ethanol) the complexes [Ru(Phen)2Dcbpy]Cl2 and [Ru(Ph2Phen)2Dcbpy]Cl2 show, respectively, the following properties: apparent pKa of 3.6 ± 0.4 and 3.7 ± 0.4; lifetimes of the protonated species 0.46 ± 0.01 ?s and 0.38 ± 0.02 ?s and ionised species 0.598 ± 0.001 ?s and 0.61 ± 0.08 ?s. The [Ru(Phen)2Dcbpy]Cl2 complex was immobilised in the tip of optical fibers using a hybrid sol-gel procedure based on tetraethoxysilan and phenyltriethoxysilan enabling pH sensitive fiber probes. The immobilised complex shows the following lifetimes: protonated species 1.05 ± 0.04 ?s and ionised species 1.16 ± 0.04 ?s. These characteristics show that these ruthenium(II) complexes are good indicators for pH sensing, either in aqueous solution or immobilised in sol-gel, and are well suited for intensity and/or frequency domain interrogation

2008-09-19

104

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 indigenous...

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

2013-01-01

105

All-in-fiber chemical sensing.  

Science.gov (United States)

A new all-in-fiber trace-level chemical sensing approach is demonstrated. Photoconductive structures, embedded directly into the fiber cladding along its entire length, capture light emitted anywhere within the fiber's hollow core and transform it directly into an electrical signal. Localized signal transduction circumvents problems associated with conventional fiber-optics, including limited signal collection efficiency and optical losses. This approach facilitates a new platform for remote and distributed photosensing. PMID:23027644

Gumennik, Alexander; Stolyarov, Alexander M; Schell, Brent R; Hou, Chong; Lestoquoy, Guillaume; Sorin, Fabien; McDaniel, William; Rose, Aimee; Joannopoulos, John D; Fink, Yoel

2012-11-27

106

Application of optical fiber sensing technology in the hydraulic decoking monitoring system  

Science.gov (United States)

On the basis of the analysis of the current hydraulic decoking monitoring system, it is proposed that use optical fiber Bragg grating (FBG) vibration sensor and fiber Fabry-Perot (FP) acoustic sensors to online monitor vibration signal and audio signal hydraulic of the coke drum in the running state progress, analysis the vibration sensor and acoustic sensor used in the system. Based on the actual monitoring results in Sinopec Wuhan Branch , the fiber optic acoustic emission sensors is more suitable for the hydraulic decoking online monitoring system than the FBG vibration sensor ,which can more accurate monitor of hydraulic decoking.

Fan, Yun-feng; Tong, Xing-lin; Ji, Tao; Gao, Xue-qing; Zhong, Dong

2013-09-01

107

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 fiber and their optical spectrum.

Karra. Sony*, Soumya. M

2013-03-01

108

Analysis of Faraday effect in multimode tellurite glass optical fiber for magneto-optical sensing and monitoring applications.  

Science.gov (United States)

The design and fabrication of a tellurite glass multimode optical fiber for magneto-optical applications are presented and discussed. The analysis of the polarization shows that an optical beam, linearly polarized at the fiber input, changes to elliptically polarized with an ellipticity of 1?4.5 after propagating down the fiber. However, the elliptical distribution remains unchanged with or without an applied magnetic field, demonstrating that no circular dichroism occurs within the fiber. The Verdet constant of the tellurite glass in the fiber is measured to be 28±0.5??rad·(T·m)-1, diverging by less than 3% from the Verdet constant found on the same glass composition in bulk form. These results demonstrate the feasibility to develop reliable tellurite glass fibers by the preform drawing method for magneto-optical applications. PMID:22772128

Shiyu, Yin; Lousteau, Joris; Olivero, Massimo; Merlo, Marco; Boetti, Nadia; Abrate, Silvio; Chen, Qiuling; Chen, Qiuping; Milanese, Daniel

2012-07-01

109

Optimized design and simulation of high temperature pressure pipeline strain monitoring with optical fiber sensing technology  

Science.gov (United States)

High temperature pressure piping have been applied widely in the chemical industry, the petroleum enterprises and the electrical power plants, and corresponding accidents happened frequently every year owing to the pipeline leakage and explosion. By massive accident statistics and analysis, the high temperature creep and the pipeline inside wall corroding are the main causes to result in the pipeline leakage and explosion accident. By real time sensing the strain change of pipeline outer surface, the online working status of the high temperature pipeline could be monitored and the leakage and explosion accidents would be avoided. Now several methods can be considered to sensing and monitoring the strain change of the high temperature pipeline surface, including Electricity sensor examination method, ultrasonic wave examination method and infrared thermal imagery examination method. After careful analysis and contrast, Electricity sensor examination method was given up for it couldn't be working steadily under high temperature conditions and easily excitated electric sparks which would result in flammable explosive danger in chemical industry and petroleum enterprises. Ultrasonic wave examination method and infrared thermal imagery examination method could avoid the shortages of Electricity sensor examination method based on the non-destructive examination theory, but the ultrasonic wave method could be applied only in examining the pipeline wall thickness, the inside wall crack as well as the material air bubble flaws restricted in its working principle. Consequently ultrasonic wave method examination method wasn't suitable to sense and monitor the strain change of the high temperature pipeline surface; Infrared thermal imagery examination method has low sensing resolution and can only examine internal etching pit and wall thickness attenuating, so it is unable to examine the pipeline surface strain change on time. Therefore three reported real-time examination methods mentioned above cannot satisfy the strain change monitoring of high temperature pressure piping. In this paper a novel method is presented using optical Fiber Bragg Grating sensor to carry on the real-time monitoring of the high temperature pressure piping surface strain change. firstly the stress and strain analysis of the high temperature pressure piping surface is given based on the established theoretical model, then optimized design and simulation is accomplished with computer ANSYS software. In the end a optimized set-up is put forward and discussed.

Zhang, Feng; Liu, Yueming; Lou, Jun

2011-06-01

110

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

Science.gov (United States)

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

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

2012-12-01

111

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

2004-01-01

112

Potential of Brillouin scattering in polymer optical fiber for strain-insensitive high-accuracy temperature sensing.  

Science.gov (United States)

We investigated the dependences of Brillouin frequency shift (BFS) on strain and temperature in a perfluorinated graded-index polymer optical fiber (PFGI-POF) at 1.55 ?m wavelength. They showed negative dependences with coefficients of -121.8 MHz/% and -4.09 MHz/K, respectively, which are -0.2 and -3.5 times as large as those in silica fibers. These unique BFS dependences indicate that the Brillouin scattering in PFGI-POFs has a big potential for strain-insensitive high-accuracy temperature sensing. PMID:21124587

Mizuno, Yosuke; Nakamura, Kentaro

2010-12-01

113

Optical fiber networks for remote fiber optic sensors.  

Science.gov (United States)

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, pros and cons. Finally, a synopsis of the main factors to take into consideration in the design of a remote sensor system is gathered. PMID:22666011

Fernandez-Vallejo, Montserrat; Lopez-Amo, Manuel

2012-01-01

114

Optical Fiber Networks for Remote Fiber Optic Sensors  

Directory of Open Access Journals (Sweden)

Full Text Available 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, pros and cons. Finally, a synopsis of the main factors to take into consideration in the design of a remote sensor system is gathered.

Montserrat Fernandez-Vallejo

2012-03-01

115

A novel approach for simultaneous sensing of urea and glucose by SPR based optical fiber multianalyte sensor.  

Science.gov (United States)

A novel design is presented for the sensing of urea and glucose simultaneously by surface plasmon resonance (SPR) based optical fiber multianalyte sensor using gel entrapment technique in a fluid for biomedical applications. Sensing surfaces are prepared by coating of different metals and high index dielectric over-layers (silver and silicon in channel 1 and copper and tin-oxide in channel 2) over two small and well separated unclad portions of an optical fiber. Enzymes urease and glucose oxidase are immobilized over respective surfaces using gel entrapment method for the sensing of urea and glucose, respectively. Wavelength interrogation technique is used for the calibration of the sensor. The concentration of urea and glucose are selected in the range 0-180 mM and 0-260 mg dl(-1), respectively, to mimic the physiological range of urea and glucose in human blood. Mixed solutions of urea and glucose with varying concentrations are prepared in buffer solution for the calibration of the sensor. The resonance wavelengths are determined corresponding to two channels responding independently to the interaction of analytes in solution on sensing channels. It is observed that the resonance wavelengths in the case of both the sensing channels decrease with the increasing concentrations of urea and glucose in solutions. The sensor gives 8.51 nm and 13.04 nm total shifts in resonance wavelength for 0 mM to 180 mM urea and 0 mg dl(-1) to 260 mg dl(-1) glucose concentrations in a sample, respectively. The advantages of the present sensor are cascaded design with multiple sensing channels on a single platform, inexpensive, simultaneous sensing of two parameters, possibility of online monitoring and remote sensing. PMID:24492310

Verma, Roli; Gupta, Banshi D

2014-03-21

116

The fiber-optic gyroscope: Challenges to become the ultimate rotation-sensing technology  

Science.gov (United States)

Taking advantage of the development of optical-fiber communication technologies, the fiber-optic gyroscope 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, but today, it reaches strategic-grade performance 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.

Lefèvre, Hervé C.

2013-12-01

117

Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants  

Energy Technology Data Exchange (ETDEWEB)

A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Previously we described a particle-in-binder approach to immobilizing the potassium salt of a molybdenum cluster, K{sub 2}Mo{sub 6}Cl{sub 14}, at the tips of optical fibers. Compared to previous methods, the particle-in-binder approach affords fibers with greatly improved mechanical properties. We have extensively characterized two fiber sensors at high temperature. We obtain quenching ratios between pure nitrogen and 21% oxygen as high as 3.9 x at 70 C. For the first sensor at 60 C we obtained a {+-} 1% variation in the quenching ratio over 6 cycles of measurement, and monitored the device performance over 23 days. We were able to operate the second sensor continuously for 14 hours at 70 C, and the sensor quenching ratio was stable to 5% over that time period. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

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

2006-01-01

118

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

CERN Document Server

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.

Wallangen, Veronica

2013-01-01

119

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)

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.

Shiquan Tao

2006-12-31

120

Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants  

Energy Technology Data Exchange (ETDEWEB)

A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Previously we described a particle-in-binder approach to immobilizing the potassium salt of the molybdenum cluster, K{sub 2}Mo{sub 6}Cl{sub 14}, at the tips of optical fibers. Compared to previous methods, the particle-in-binder approach affords fibers with greatly improved mechanical properties. The response of the sensor to oxygen at 40, 70 and 100 C was measured in 2-21% gas phase oxygen. The normalized sensor signal is linear with molar oxygen concentration and fits the theoretical Stern-Volmer relationship. Although the sensitivity decreases with temperature, at 100 C the sensitivity is 160 [O{sub 2}]{sup -1}. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

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

2006-05-01

 
 
 
 
121

Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants  

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-10-01

122

Fiber optic monitoring device  

Energy Technology Data Exchange (ETDEWEB)

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

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

1993-01-01

123

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)

2013-06-01

124

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 optical fibers for heat-flow measurements of special nuclear material. This calorimeter uses piezoelectric-generated phase-carrier modulation with subsequent electronic signal processes to allow phase shifts as small as 1 microradian (microrad) 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% "2"4"0Pu). The system noise base was about 0.2 rad, equivalent to about 1 mg of plutonium

1997-01-01

125

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 optical fibers 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 microrad 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 rad of phase shift per mW of thermal power. One milliwatt of thermal power is equivalent to 400 mg of plutonium (6% "2"4"0Pu). The system noise base was about 0.2 rad, equivalent to about 1 mg of plutonium

1998-07-26

126

Evanescent field characteristics of eccentric core optical fiber for distributed sensing.  

Science.gov (United States)

Fundamental core-mode cutoff and evanescent field are considered for an eccentric core optical fiber (ECOF). A method has been proposed to calculate the core-mode cutoff by solving the eigenvalue equations of an ECOF. Using conformal mapping, the asymmetric geometrical structure can be transformed into a simple, easily solved axisymmetric optical fiber with three layers. The variation of the fundamental core-mode cut-off frequency (V(c)) is also calculated with different eccentric distances, wavelengths, core radii, and coating refractive indices. The fractional power of evanescent fields for ECOF is also calculated with the eccentric distances and coating refractive indices. These calculations are necessary to design the structural parameters of an ECOF for long-distance, single-mode distributed evanescent field absorption sensors. PMID:24690642

Liu, Jianxia; Yuan, Libo

2014-03-01

127

High-resolution temperature sensing in the Dead Sea using fiber optics  

Science.gov (United States)

thermal stratification of the Dead Sea was observed in high spatial and temporal resolution by means of fiber-optics temperature sensing. The aim of the research was to employ the novel high-resolution profiler in studying the dynamics of the thermal structure of the Dead Sea and the related processes including the investigation of the metalimnion fluctuations. The 18 cm resolution profiling system was placed vertically through the water column supported by a buoy 450 m from shore, from 2 m above to 53 m below the water surface (just above the local seafloor), covering the entire seasonal upper layer (the metalimnion had an average depth of ˜20 m). Temperature profiles were recorded every 5 min. The May to July 2012 data set allowed quantitative investigation of the thermal morphology dynamics, including objective definitions of key locations within the metalimnion based on the temperature depth profile and its first and second depth derivatives. Analysis of the fluctuation of the defined metalimnion locations showed strong anticorrelation to measured sea level fluctuations. The slope of the sea level versus metalimnion depth was found to be related to the density ratio of the upper layer and the underlying main water body, according to the prediction of a two-layer model. The heat content of the entire water column was calculated by integrating the temperature profiles. The vertically integrated apparent heat content was seen to vary by 50% in a few hours. These fluctuations were not correlated to the atmospheric heat fluxes, nor to the momentum transfer, but were highly correlated to the metalimnion and the sea level fluctuations (r = 0.84). The instantaneous apparent heat flux was 3 orders of magnitude larger than that delivered by radiation, with no direct correlation to the frequency of radiation and wind in the lake. This suggests that the source of the momentary heat flux is lateral advection due to internal waves (with no direct relation to the diurnal cycle). In practice, it is shown that snap-shot profiles of the Dead Sea as obtained with standard thermal profilers will not represent the seasonal typical status in terms of heat content of the upper layer.

Arnon, A.; Lensky, N. G.; Selker, J. S.

2014-02-01

128

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

Energy Technology Data Exchange (ETDEWEB)

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

Battista, L.; Sciuto, S. A.; Scorza, A. [Department of Engineering, ROMA TRE University, via della Vasca Navale 79/81, Rome (Italy)

2013-03-15

129

System and method for determination of the reflection wavelength of multiple low-reflectivity bragg gratings in a sensing optical fiber  

Science.gov (United States)

A system and method for determining a reflection wavelength of multiple Bragg gratings in a sensing optical fiber comprise: (1) a source laser; (2) an optical detector configured to detect a reflected signal from the sensing optical fiber; (3) a plurality of frequency generators configured to generate a signal having a frequency corresponding to an interferometer frequency of a different one of the plurality of Bragg gratings; (4) a plurality of demodulation elements, each demodulation element configured to combine the signal produced by a different one of the plurality of frequency generators with the detected signal from the sensing optical fiber; (5) a plurality of peak detectors, each peak detector configured to detect a peak of the combined signal from a different one of the demodulation elements; and (6) a laser wavenumber detection element configured to determine a wavenumber of the laser when any of the peak detectors detects a peak.

Moore, Jason P. (Inventor)

2009-01-01

130

Spheroidal Fabry-Perot microcavities in optical fibers for high-sensitivity sensing.  

Science.gov (United States)

All-optical-fiber Fabry-Perot interferometers (FPIs) with microcavities of different shapes were investigated. It was found that the size and shape of the cavity plays an important role on the performance of these interferometers. To corroborate the analysis, FPIs with spheroidal cavities were fabricated by splicing a photonic crystal fiber (PCF) with large voids and a conventional single mode fiber (SMF), using an ad hoc splicing program. It was found that the strain sensitivity of FPIs with spheroidal cavities can be controlled through the dimensions of the spheroid. For example, a FPI whose cavity had a size of ~10x60 ?m exhibited strain sensitivity of ~10.3 pm/?? and fringe contrast of ~38 dB. Such strain sensitivity is ~10 times larger than that of the popular fiber Bragg gratings (~1.2 pm/??) and higher than that of most low-finesse FPIs. The thermal sensitivity of our FPIs is extremely low (~1pm/°C) due to the air cavities. Thus, a number of temperature-independent ultra-sensitive microscopic sensors can be devised with the interferometers here proposed since many parameters can be converted to strain. To this end, simple vibration sensors are demonstrated. PMID:22453393

Favero, F C; Araujo, L; Bouwmans, G; Finazzi, V; Villatoro, J; Pruneri, V

2012-03-26

131

Interferometric Fiber Optic Sensors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 t...

Byeong Ha Lee; Young Ho Kim; Kwan Seob Park; Joo Beom Eom; Myoung Jin Kim; Byung Sup Rho; Hae Young Choi

2012-01-01

132

Chemical sensing by differential thermal analysis with a digitally controlled fiber optic interferometer  

Science.gov (United States)

In this work the implementation of an optical fiber interferometric system for differential thermal analysis enabling the identification of chemical species is described. The system is based on a white light Mach-Zehnder configuration using pseudo-heterodyne demodulation to interrogate two identical fiber Bragg gratings (FBG) in a differential scheme. System performance is compared using either standard hardware or low cost virtual instrumentation for operation control and signal processing. The operation with the virtual system enabled temperature measurements with a +/-0.023 °C resolution nearly matching the performance of the standard hardware. The system ability to discriminate chemical species by differential thermal analysis was demonstrated. Mixed samples of acetone and methanol could be successfully identified, indicating the suitability of the system for high precision measurements using low cost instrumentation.

Gonçalves, L. C.; González-Aguilar, G.; Fraza~o, O.; Baptista, J. M.; Jorge, P. A. S.

2013-01-01

133

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

1998-01-01

134

Assessment of GeB doped SiO2 optical fiber for the application of remote radiation sensing system  

Science.gov (United States)

The research and development efforts on the silica (SiO2) optical fiber for application in radiation sensing and other dosimetry field have become quite active. The widely used LiF based dosimeter (TLD) has shown a relatively low reproducibility and there is a time delay in dose assessment which loses its capability as direct real-time dose assessment dosimeters unlike diodes. The macroscopic size of the optical fiber generally does not allow direct in vivo dose sensing in the inner organ for radiotherapy and medical imaging. A flat optical fiber (FF) with nominal dimensions of (0.08 x10 x 10) mm3 of pure silica SiO2 and GeO2 with Boron doped silica fiber SiO2 was selected for this research. The Germanium was used a dopant to enhance the flat optical fiber to reach much higher responsiveness and dose sensitivity in high energy and high dose irradiation. Together with this combination, both TLD dimension and dose assessment issues was hoped to be overcome. The research conducted by comparing the response of pure silica SiO2 flat optical fiber with a GeO2 with Boron doped silica SiO2 flat optical fiber. The FF sample was annealed at 400°C for one hour before irradiated. Kinetic parameters and dosimetric glow curve of TL response and sensitivity were studied with respect to the electron beam of high dose of micro beam irradiation of 1.0 kGy, 5.0 kGy, 10.0 kGy, 50.0 kGy, 100.0 kGy, 500.0 kGy, and 1.0 MGy using Singapore Synchrotron Light Source's (PCIT) beamline. The PCIT operates at 500mA current with real time current range from 90-100mA, dose rate of 3.03 MGy/hour and energy at 8.9KeV. The source to Source Surface Distance (SSD) was at 6.0 cm, with a field size of 20mm × 8mm diameter of a half circle. The TL response was measured using a TLD reader Harshaw Model 3500. The Time-Temperature-Profile (TTP) of the reader was obtained to a preheat temperature of 150 °C for 5 s, the output signal being acquired at a temperature ramprate of 35 °Cs-1, acquisition time of 10 s and a maximum temperature of 400 °C each of the FF samples. All reading was taken under N2 gas flow, suppressing oxidation and potential triboluminescence. The proposed FF shows the excellent TL response for high energy irradiation and good reproducibility and exhibits a very low rate of fading and low variation background signal. From these results, the proposed FF can be used as a radiation dosimeter in remote radiation sensing and favorably compares with the widely used of LiF based dosimeter on common medical radiotherapy application.

Alawiah, A.; Fadhli, M. M.; Bauk, S.; Abdul-Rashid, H. A.; Maah, M. J.

2013-12-01

135

Comparison of Al2O3 nano-overlays deposited with magnetron sputtering and atomic layer deposition on optical fibers for sensing purposes  

Science.gov (United States)

In this work we compare effects of thin (ALD) vapor deposition methods on optical fibers. We investigate an influence of the process parameters on optical properties of the nano-films deposited with MS. In order to investigate the properties of the films directly on the fibers, we induced long-period fiber grating (LPG) in the fiber prior the deposition. Thanks to LPG sensitivity to thickness and optical properties of the overlays deposited on the fiber, we are able to monitor Al2O3 nano-overlay properties. Moreover, we investigate an influence of the overlays deposited with both the methods on LPG-based refractive index (RI) sensing. We show and discuss tuning of the RI sensitivity by proper selection of both thickness and optical properties of the Al2O3 nano-overlays.

?mietana, Mateusz; DrÄ ?ewski, Tomasz; Firek, Piotr; Mikulic, Predrag; Bock, Wojtek J.

2013-12-01

136

Fiber optic connector  

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-01-01

137

Subsea downhole optical sensing  

International Nuclear Information System (INIS)

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

2009-07-01

138

Gated Fiber Optic Transmission.  

Science.gov (United States)

A gated fiber optic sensor system is disclosed for increasing the effective optical path of a length of optical fiber cable. A pulse of polarized light having a known optical wavelength is directed into a length of optical fiber cable for propagation ther...

L. C. Bobb

1982-01-01

139

Interferometric fiber optic sensors.  

Science.gov (United States)

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. PMID:22736961

Lee, Byeong Ha; Kim, Young Ho; Park, Kwan Seob; Eom, Joo Beom; Kim, Myoung Jin; Rho, Byung Sup; Choi, Hae Young

2012-01-01

140

Interferometric Fiber Optic Sensors  

Directory of Open Access Journals (Sweden)

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.

Hae Young Choi

2012-02-01

 
 
 
 
141

A sensing element based on a bent and elongated grooved polymer optical fiber.  

Science.gov (United States)

An experimental and numerical investigation is performed into the power loss induced in grooved polymer optical fibers (POFs) subjected to combined bending and elongation deformations. The power loss is examined as a function of both the groove depth and the bend radius. An elastic-plastic three-dimensional finite element model is constructed to simulate the deformation in the grooved region of the deformed specimens. The results indicate that the power loss increases significantly with an increasing bending displacement or groove depth. Specifically, the power loss increases to as much as 12% given a groove depth of 1.1 mm and a bending displacement of 10 mm. Based on the experimental results, an empirical expression is formulated to relate the power loss with the bending displacement for a given groove depth. It is shown that the difference between the estimated power loss and the actual power loss is less than 2%. PMID:22969356

Lu, Wei-Hua; Chen, Li-Wen; Xie, Wen-Fu; Chen, Yung-Chuan

2012-01-01

142

A Sensing Element Based on a Bent and Elongated Grooved Polymer Optical Fiber  

Directory of Open Access Journals (Sweden)

Full Text Available An experimental and numerical investigation is performed into the power loss induced in grooved polymer optical fibers (POFs subjected to combined bending and elongation deformations. The power loss is examined as a function of both the groove depth and the bend radius. An elastic-plastic three-dimensional finite element model is constructed to simulate the deformation in the grooved region of the deformed specimens. The results indicate that the power loss increases significantly with an increasing bending displacement or groove depth. Specifically, the power loss increases to as much as 12% given a groove depth of 1.1 mm and a bending displacement of 10 mm. Based on the experimental results, an empirical expression is formulated to relate the power loss with the bending displacement for a given groove depth. It is shown that the difference between the estimated power loss and the actual power loss is less than 2%.

Wen-Fu Xie

2012-06-01

143

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

Science.gov (United States)

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.

Villalba, Sergi; Casas, Joan R.

2013-08-01

144

Fiber Singular Optics  

Directory of Open Access Journals (Sweden)

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.

A. V. Volyar

2002-06-01

145

Fiber optic ring network  

Energy Technology Data Exchange (ETDEWEB)

An optical fiber cable distribution architecture and a ring interface are described. The unique synergism of the ring configuration coupled with a widespread optical fiber cable facility are explored. The ring interface adapts a token passing network of work-stations from coaxial cable to 50 micron core, telecommunications type, fiber optic cable. The optical fiber cable links a series of communications centers to as many as 288 optical fibers. The loop distribution of optical fibers forms the backbone for a 6.7 km ring operating at 6 to 12 Mbps.

Gossage, S.A.

1985-01-01

146

Geothermal point sources identified in a fumarolic ice cave on Erebus volcano, Antarctica using fiber optic distributed temperature sensing  

Science.gov (United States)

Degassing of CO2 on the flanks of the active Erebus volcano is thought to occur mainly through fumarolic ice caves (FIC) and associated fumarolic ice towers. There is also minor CO2 degassing from isolated areas of warm ground. The mechanism supplying heat and CO2 gas into the FIC is poorly understood. To investigate this system, a fiber optic distributed temperature sensing (DTS) system was deployed in a FIC to obtain temperature measurements every meter. The DTS data reveal that localized gas vents (GV) supply heat to the FIC air mass and are an important component of the FIC microclimate. FIC temperature is anti-correlated with local atmospheric pressure, indicating barometric pumping of the GV. These results enable the use of FIC temperature as a proxy for flank degassing rate on Erebus, and represent the first application of DTS for monitoring an active volcano.

Curtis, Aaron; Kyle, Philip

2011-08-01

147

Fiber Optic Ring Network.  

Science.gov (United States)

An optical fiber cable distribution architecture and a ring interface are described. The unique synergism of the ring configuration coupled with a widespread optical fiber cable facility are explored. The ring interface adapts a token passing network of w...

S. A. Gossage

1985-01-01

148

Fiber optics in adverse environments  

Energy Technology Data Exchange (ETDEWEB)

Radiation effects in optical fibers are considered, taking into account recent progress in the investigation of radiation resistant optical fibers, radiation damage in optical fibers, radiation-induced transient absorption in optical fibers, X-ray-induced transient attenuation at low temperatures in polymer clad silica (PCS) fibers, optical fiber composition and radiation hardness, the response of irradiated optical waveguides at low temperatures, and the effect of ionizing radiation on fiber-optic waveguides. Other topics explored are related to environmental effects on components of fiber optic systems, and radiation detection systems using optical fibers. Fiber optic systems in adverse environments are also discussed, giving attention to the survivability of Army fiber optics systems, space application of fiber optics systems, fiber optic wavelength multiplexing for civil aviation applications, a new fiber optic data bus topology, fiber optics for aircraft engine/inlet control, and application of fiber optics in high voltage substations.

Lyous, P.B.

1982-01-01

149

Calibration of fiber Bragg gratings for optical sensing (FIBOS) for an aerospace application  

Science.gov (United States)

Fiber Bragg grating Sensors, FBGs, have been widely used as optical sensors for structural health monitoring of different materials. They can be embedded in composite structures or attached on their surface to monitor the entire life cycle of the material or to measure different physical parameters. FIBOS contains two FBGs and will be used to measure temperature and strain during the aerospace mission OPTOS. OPTOS is a picosatellite, designed and manufactured by the Spanish Institute for Aerospace Technology, INTA that will be launched during the summer 2009. The main goal of the mission is to demonstrate the possibility of using some novel technologies for space applications inside a miniaturized space and with big restrictions in terms of mass and power consumption. The paper describes the different units that constitute the FIBOS payload: one tunable laser, two FBGs mounted onto one steel mechanical structure to monitor independently temperature and strain and the processing unit that include all the electronics to control and connect the payload with the DOT of the satellite. Calibration measurements at different temperatures inside a thermalvacuum chamber as well as FIBOS operation during the mission are also presented.

Heredero, R. L.; Frovel, M.; Laguna, H.; Belenguer-Dávila, T.

2009-03-01

150

Power loss characteristics of a sensing element based on a grooved polymer optical fiber under elongation  

International Nuclear Information System (INIS)

This study conducts a numerical and experimental investigation into the effects of elongation on the power attenuation characteristics of grooved polymer optical fibers (POFs). POFs with groove depths ranging from 0 to 1.1 mm are tensile tested. The load–elongation data are then used to compute the corresponding average plastic energy density (APED). An elastic–plastic three-dimensional finite element model is used to simulate the deformation which takes place near the grooved region of the elongated POF in order to clarify the experimental results. In general, the results show that the change rate of the power ratio or the sensitivity increases with increasing elongation and increasing groove depth. By applying a curve-fitting technique, an empirical expression is developed to relate the power ratio to the APED and the groove depth. It is found that the difference between the predicted values obtained from the proposed equation and the experimental results is less than 7%, thus confirming the APED to be a meaningful index with which to evaluate the sensitivity of POF sensors

2008-10-01

151

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

Science.gov (United States)

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.

Richards, Lance

2014-01-01

152

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

Directory of Open Access Journals (Sweden)

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

Chunguang Lan

2012-04-01

153

Specialty optical fibers: revisited  

Science.gov (United States)

The paper contains description of chosen aspects of analysis and design of tailored optical fibers. By specialty optical fibers we understand here the fibers which have complex construction and which serve for the functional processing of optical signal rather than long distance transmission. Thus, they are called also instrumentation optical fibers. The following issues are considered: transmission properties, transformation of optical signal, fiber characteristics, fiber susceptibility to external reactions. The technology of tailored optical fibers offers a wider choice of the design tools for the fiber itself, and then various devices made from these fiber, than classical technology of communication optical fibers. The consequence is different fiber properties, nonstandard dimensions and different metrological problems. The price to be paid for wider design possibilities are bigger optical losses of these fibers and weaker mechanical properties, and worse chemical stability. These fibers find their applications outside the field of telecommunications. The applications of instrumentation optical fibers combine other techniques apart from the photonics ones like: electronic, chemical and mechatronic.

Romaniuk, Ryszard S.

2011-06-01

154

Optical Sensors Based on Plastic Fibers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The recent advances of polymer technology allowed the introduction of plastic optical fiber in sensor design. The advantages of optical metrology with plastic optical fiber have attracted the attention of the scientific community, as they allow the development of low-cost or cost competitive systems compared with conventional technologies. In this paper, the current state of the art of plastic optical fiber technology will be reviewed, namely its main characteristics and sensing advantages. S...

Lúcia Bilro; Nélia Alberto; Pinto, Joa?o L.; Rogério Nogueira

2012-01-01

155

Random-access distributed fiber sensing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

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

2012-01-01

156

PetroSense reg-sign CMS 5000, a fiber optic chemical sensing system for leak detection  

International Nuclear Information System (INIS)

The PetroSense reg-sign CMS 5000 is a continuous monitoring system for the monitoring to total hydrocarbons. It is capable of providing real time, in-situ monitoring of hydrocarbons in water, vapor, soil and water/vapor interface. To monitor leaks for storage tanks the PetroSense reg-sign probes have to be placed under or around these tanks. In this paper the performance of the CMS 5000 probes under simulated field conditions will be described along with data from a field installation

1995-06-19

157

Focused ion beam post-processing of optical fiber Fabry-Perot cavities for sensing applications.  

Science.gov (United States)

Focused ion beam technology is combined with chemical etching of specifically designed fibers to create Fabry-Perot interferometers. Hydrofluoric acid is used to etch special fibers and create microwires with diameters of 15 ?m. These microwires are then milled with a focused ion beam to create two different structures: an indented Fabry-Perot structure and a cantilever Fabry-Perot structure that are characterized in terms of temperature. The cantilever structure is also sensitive to vibrations and is capable of measuring frequencies in the range 1 Hz - 40 kHz. PMID:24921506

André, Ricardo M; Pevec, Simon; Becker, Martin; Dellith, Jan; Rothhardt, Manfred; Marques, Manuel B; Donlagic, Denis; Bartelt, Hartmut; Frazão, Orlando

2014-06-01

158

Fiber optic sensors for nuclear power plants  

Energy Technology Data Exchange (ETDEWEB)

Fiber optic sensors are being considered as potential replacements for some of the conventional sensors in the nuclear power industry. Fiber optic sensing technology offers performance enhancements over conventional systems in terms of dynamic range, sensitivity, signal isolation, distributed measurement, reduced size and mass, and resistance to high temperatures, vibration, electromagnetic interference, and radiation. The electronic components of a fiber optic sensing system may be located remotely, allowing installation of the sensing element in electrically noisy, chemically hazardous, or potentially explosive process measurement environments.

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

1994-10-01

159

Fiber optic sensors for nuclear power plants  

International Nuclear Information System (INIS)

Fiber optic sensors are being considered as potential replacements for some of the conventional sensors in the nuclear power industry. Fiber optic sensing technology offers performance enhancements over conventional systems in terms of dynamic range, sensitivity, signal isolation, distributed measurement, reduced size and mass, and resistance to high temperatures, vibration, electromagnetic interference, and radiation. The electronic components of a fiber optic sensing system may be located remotely, allowing installation of the sensing element in electrically noisy, chemically hazardous, or potentially explosive process measurement environments

1994-10-01

160

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

DEFF Research Database (Denmark)

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

Frosz, Michael Henoch; Stefani, Alessio

2011-01-01

 
 
 
 
161

Hydrogen Optical Fiber Sensors  

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-07-28

162

A neodymium doped hollow optical fiber laser for applications in sensing and laser guided atoms  

Science.gov (United States)

The development of a diode pumped capillary fiber laser is described. Its emission properties are changed by influencing the evanescent field. Besides its application as a sensor device, the usability of such a laser is illustrated for the example of guiding atoms on straight and curved paths.

Glas, P.; Naumann, M.; Schirrmacher, A.; Pertsch, Th.

1999-08-01

163

Rayleigh fiber optics gyroscope  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Kung, A.; Budin, J.; The?venaz, Luc; Robert, P. A.

1997-01-01

164

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

1978-09-14

165

Polarization in optical fibers  

CERN Multimedia

This essential book analyzes polarization effects, including non-linear effects, and their influence in communications and sensing. You get full details on telecom system degradation caused by PMD, PDL, and PDG and techniques for mitigating it, plus insight into the effects and consequences of polarization on solitons, amplifiers, and switches. Fiber polarization in sensing applications is explained through detailed treatment of such key issues as stress/strain, displacement, point sensing, and distributed sensing.

Rogers, Alan

2008-01-01

166

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

CERN Document Server

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

Loas, Goulc'hen; Vallet, Marc

2014-01-01

167

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

Science.gov (United States)

We present a setup dedicated to the measurement of the small scalar directional anisotropies associated to the magnetochiral interaction. The apparatus, based on a polarization-independent fiber Sagnac interferometer, is optimized to be insensitive to circular anisotropies and to residual absorption. It can thus characterize samples of biological interests, for which the two enantiomers are not available and/or which present poor transmission. The signal-to-noise ratio is shown to be limited only by the source intensity noise, leading to a detection limit of ?? = 500 nrad?Hz(-1/2). It yields a limit on the magnetochiral index nMC < 4 × 10(-13) T(-1) at 1.55 ?m for the organic molecules tested. PMID:24784595

Loas, G; Alouini, M; Vallet, M

2014-04-01

168

Fiber optics development, prospects assessed  

Science.gov (United States)

The status of fiber optics technology in Poland is discussed. Application of fiber optics to telecommunication and military radar is mentioned. Internal problems slowing the development of Polish fiber optics technology are addressed.

Marks, B.

1984-10-01

169

Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants  

Energy Technology Data Exchange (ETDEWEB)

Spectroscopy of Mo{sub 6}Cl{sub 12} immobilized in a sol-gel matrix and heated to 200 C has been performed. Oxygen quenching of the luminescence was observed. Aging Mo{sub 6}Cl{sub 12} to temperatures above 250 C converts the canary yellow Mo{sub 6}Cl{sub 12} to a non-luminescent gray solid. Preliminary experiments point to oxidation of the clusters as the likely cause of thermally induced changes in the physical and optical properties of the clusters.

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

2003-09-30

170

Python fiber optic seal  

Energy Technology Data Exchange (ETDEWEB)

Sandia National Laboratories has developed a high security fiber optic seal that incorporates tamper resistance features that are not available in commercial fiber optic seals. The Python Seal is a passive fiber optic loop seal designed to give indication of unauthorized entry. The seal includes a fingerprint feature that provides seal identity information in addition to the unique fiber optic pattern created when the seal is installed. The fiber optic cable used for the seal loop is produced with tamper resistant features that increase the difficulty of attacking that component of a seal. A Seal Reader has been developed that will record the seal signature and the fingerprint feature of the seal. A Correlator software program then compares seal images to establish a match or mismatch. SNL is also developing a Polaroid reader to permit hard copies of the seal patterns to be obtained directly from the seal.

Ystesund, K.; Bartberger, J.; Brusseau, C.; Fleming, P.; Insch, K.; Tolk, K.

1993-08-01

171

Chemical Sensing Using Fiber Cavity Ring-Down Spectroscopy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

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

2010-01-01

172

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

Science.gov (United States)

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

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

2013-12-01

173

Investigation of gold-coated bare fiber probe for in situ intra-vitreous coherence domain optical imaging and sensing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have investigated the usage of gold-plated bare fiber probes for in situ imaging of retinal layers and surrounding ocular tissues using time-domain common-path optical coherence tomography. The fabricated intra-vitreous gold-plated micro-fiber probe can be fully integrated with surgical tools working in close proximity to the tissue to provide subsurface images having a self-contained reference plane independent to the Fresnel reflection between the distal end of the probe and the followin...

2010-01-01

174

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

Science.gov (United States)

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

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

2014-05-01

175

Optic Radiation Fiber Tractography in Glioma Patients Based on High Angular Resolution Diffusion Imaging with Compressed Sensing Compared with Diffusion Tensor Imaging - Initial Experience  

Science.gov (United States)

Objective Up to now, fiber tractography in the clinical routine is mostly based on diffusion tensor imaging (DTI). However, there are known drawbacks in the resolution of crossing or kissing fibers and in the vicinity of a tumor or edema. These restrictions can be overcome by tractography based on High Angular Resolution Diffusion Imaging (HARDI) which in turn requires larger numbers of gradients resulting in longer acquisition times. Using compressed sensing (CS) techniques, HARDI signals can be obtained by using less non-collinear diffusion gradients, thus enabling the use of HARDI-based fiber tractography in the clinical routine. Methods Eight patients with gliomas in the temporal lobe, in proximity to the optic radiation (OR), underwent 3T MRI including a diffusion-weighted dataset with 30 gradient directions. Fiber tractography of the OR using a deterministic streamline algorithm based on DTI was compared to tractography based on reconstructed diffusion signals using HARDI+CS. Results HARDI+CS based tractography displayed the OR more conclusively compared to the DTI-based results in all eight cases. In particular, the potential of HARDI+CS-based tractography was observed for cases of high grade gliomas with significant peritumoral edema, larger tumor size or closer proximity of tumor and reconstructed fiber tract. Conclusions Overcoming the problem of long acquisition times, HARDI+CS seems to be a promising basis for fiber tractography of the OR in regions of disturbed diffusion, areas of high interest in glioma surgery.

Kuhnt, Daniela; Bauer, Miriam H. A.; Sommer, Jens; Merhof, Dorit; Nimsky, Christopher

2013-01-01

176

Fiber Optic Cables  

Science.gov (United States)

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, LEDâÂÂs, 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.

Bartelt, Terry L.

2009-04-28

177

Tapered Optical Fiber Sensor.  

Science.gov (United States)

A sensor is disclosed in which light is launched into the core of a single mode optical fiber having a tapered-down or narrow waist region between 2 tapers along an internal portion of the length thereof. The fiber is positioned so that a physical effect ...

H. D. Krumboltz L. C. Bobb

1992-01-01

178

Investigation of gold-coated bare fiber probe for in situ intra-vitreous coherence domain optical imaging and sensing  

Science.gov (United States)

We have investigated the usage of gold-plated bare fiber probes for in situ imaging of retinal layers and surrounding ocular tissues using time-domain common-path optical coherence tomography. The fabricated intra-vitreous gold-plated micro-fiber probe can be fully integrated with surgical tools working in close proximity to the tissue to provide subsurface images having a self-contained reference plane independent to the Fresnel reflection between the distal end of the probe and the following medium for achieving reference in typical common-path optical coherence tomography. We have fully characterized the probe in an aqueous medium equivalent to the vitreous humor in the eye and were able to differentiate various functional retinal tissue layers whose thickness is larger than the system’s resolution.

Han, J.-H.; Ilev, I. K.; Kim, D.-H.; Song, C. G.; Kang, J. U.

2010-06-01

179

Optical fiber switch  

Energy Technology Data Exchange (ETDEWEB)

Optical fiber switches operated by electrical activation of at least one laser light modulator through which laser light is directed into at least one polarizer are used for the sequential transport of laser light from a single laser into a plurality of optical fibers. In one embodiment of the invention, laser light from a single excitation laser is sequentially transported to a plurality of optical fibers which in turn transport the laser light to separate individual remotely located laser fuel ignitors. The invention can be operated electro-optically with no need for any mechanical or moving parts, or, alternatively, can be operated electro-mechanically. The invention can be used to switch either pulsed or continuous wave laser light.

Early, James W. (Los Alamos, NM); Lester, Charles S. (San Juan Pueblo, NM)

2002-01-01

180

Lanthanide upconversion within microstructured optical fibers: improved detection limits for sensing and the demonstration of a new tool for nanocrystal characterization.  

Science.gov (United States)

We investigate a powerful new sensing platform based on the excitation of upconversion luminescence from NaYF(4):Yb/Er nanocrystals loaded in solution within a suspended-core microstructured optical fiber. We demonstrate a substantial improvement in the detection limit that can be achieved in a suspended-core fiber sensor for solution-based measurements using these nanocrystals as an alternative to more traditional fluorophores, with sensing of concentrations as low as 660 fM demonstrated compared with the 10 pM obtained using quantum dots. This nanocrystal loaded suspended core fiber platform also forms the basis for a novel and robust nanoscale spectrometry device capable of capturing power-dependent spectra over a large dynamic range from 10(3) W cm(-2) to 10(6) W cm(-2) using a laser diode. This serves as a useful tool to study the multiple energy levels of rare earth luminescent nano-materials, allowing the two sharp emission bands to be studied in detail over a large dynamic range of excitation powers. Thus, in addition to demonstrating a highly sensitive dip sensor, we have devised a powerful new approach for characterizing upconversion nanoparticles. PMID:23086019

Schartner, Erik P; Jin, Dayong; Ebendorff-Heidepriem, Heike; Piper, James A; Lu, Zhenda; Monro, Tanya M

2012-12-01

 
 
 
 
181

Multimode fiber optics  

Science.gov (United States)

In 2012, Loyola University Maryland and Rockhurst University received a grant to develop three upper-­?division active learning physics modules that relate physics principles to medicine. One of these modules is concerned with multimode fiber optics. The teaching materials for fiber optics are divided into two levels: Level 1 is appropriate for introductory/intermediate students and Level 2 is designed for intermediate/advanced students. Level 2 materials concentrate on the physics and experimental techniques of coupling laser light into a 200 um fiber, and are suitable for students who may encounter optics in research or industrial environments. In the process of working with Level 2 materials, the students will learn about numerical aperture, beam waist due to diffraction and spherical aberration, optical alignment techniques, overfilling and underfilling of fibers, skew rays, loss, and applications of fiber optics in medicine and other fields. We wish to acknowledge support from NSF TUES grant 1140406. Presented at the 2013 AAPT Summer Meeting, W36: Advanced Labs Workshop

Lowe, Mary

2013-10-02

182

Power Loss Characteristics of a Sensing Element Based on a Polymer Optical Fiber under Cyclic Tensile Elongation  

Science.gov (United States)

In this study, power losses in polymer optical fiber (POF) subjected to cyclic tensile loadings are studied experimentally. The parameters discussed are the cyclic load level and the number of cycles. The results indicate that the power loss in POF specimens increases with increasing load level or number of cycles. The power loss can reach as high as 18.3% after 100 cyclic loadings. Based on the experimental results, a linear equation is proposed to estimate the relationship between the power loss and the number of cycles. The difference between the estimated results and the experimental results is found to be less than 3%.

Chen, Yung-Chuan; Chen, Li-Wen; Lu, Wei-Hua

2011-01-01

183

Optical fiber stripper positioning apparatus  

Energy Technology Data Exchange (ETDEWEB)

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

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

1990-01-01

184

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

International Nuclear Information System (INIS)

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

2000-01-01

185

Quasi-distributed long-gauge fiber optic sensor system  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Linec, Matjaz?; Ðonlagic?, Denis

2012-01-01

186

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.)

1998-06-09

187

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

1995-01-01

188

Assessment of fiber optic pressure sensors  

Energy Technology Data Exchange (ETDEWEB)

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.

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

1995-04-01

189

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)

2013-01-01

190

Optical fiber fault location method.  

Science.gov (United States)

An optical pulse reflection method based on the optical radar principle is discussed for optical fiber cable fault location. The optical reflection coefficient at flat surfaces of optical fibers was measured and found to be in good agreement with calculated value. The average reflection coefficient at fractures in optical fibers, which were generated by simple tensile stress, was about 0.5%. The reflected pulse signal from an optical fiber fault at a distance of 1.4 km in a SELFOC fiber having transmission loss of 17 dB/km was detected experimentally. PMID:20165194

Ueno, Y; Shimizu, M

1976-06-01

191

Applications of nonlinear fiber optics  

CERN Document Server

* The only book describing applications of nonlinear fiber optics * Two new chapters on the latest developments: highly nonlinear fibers and quantum applications* Coverage of biomedical applications* Problems provided at the end of each chapterThe development of new highly nonlinear fibers - referred to as microstructured fibers, holey fibers and photonic crystal fibers - is the next generation technology for all-optical signal processing and biomedical applications. This new edition has been thoroughly updated to incorporate these key technology developments.The bo

Agrawal, Govind P

2008-01-01

192

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.)

2001-05-01

193

Nanophotonics of optical fibers  

Science.gov (United States)

This review is concerned with nanoscale effects in highly transparent dielectric photonic structures fabricated from optical fibers. In contrast to those in plasmonics, these structures do not contain metal particles, wires, or films with nanoscale dimensions. Nevertheless, a nanoscale perturbation of the fiber radius can significantly alter their performance. This paper consists of three parts. The first part considers propagation of light in thin optical fibers (microfibers) having the radius of the order of 100 nanometers to 1 micron. The fundamental mode propagating along a microfiber has an evanescent field which may be strongly expanded into the external area. Then, the cross-sectional dimensions of the mode and transmission losses are very sensitive to small variations of the microfiber radius. Under certain conditions, a change of just a few nanometers in the microfiber radius can significantly affect its transmission characteristics and, in particular, lead to the transition from the waveguiding to non-waveguiding regime. The second part of the review considers slow propagation of whispering gallery modes in fibers having the radius of the order of 10-100 microns. The propagation of these modes along the fiber axis is so slow that they can be governed by extremely small nanoscale changes of the optical fiber radius. This phenomenon is exploited in SNAP (surface nanoscale axial photonics), a new platform for fabrication of miniature super-low-loss photonic integrated circuits with unprecedented sub-angstrom precision. The SNAP theory and applications are overviewed. The third part of this review describes methods of characterization of the radius variation of microfibers and regular optical fibers with sub-nanometer precision.

Sumetsky, M.

2013-12-01

194

Integrated optics for fiber optic sensors  

Science.gov (United States)

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.

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

1991-01-01

195

Reduced Gravity Zblan Optical Fiber  

Science.gov (United States)

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

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

2000-01-01

196

Micromachined optical fiber current sensor  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We describe a micromachined optical fiber current sensor. The sensing element consists of a squared silicon membrane (8 mm long and 20 ?m thick) that has a cylindrical permanent magnet (NdFeB alloy, 3-mm diameter, 1.5 mm high) fixed on its central region. This structure allows the permanent magnet to vibrate in the presence of the magnetic field gradient generated by an ac. A linear relation between the electrical current and the magnet displacement was measured with white-light interferomet...

Heredero, R. L.; Ferna?ndez Caleya, Ramo?n; Guerrero, He?ctor; Losantos Vin?olas, Pedro; Acero, M. C.; Esteve, J.

1999-01-01

197

Fiber optics turbidity sensor  

Science.gov (United States)

The aim of this paper is the presentation of constructed and investigation models of fiber-optic sensors used as turbidimeters. Sensors were designed in two versions: for examination of liquid samples and for monitoring of transparency in the flow of liquids (`on-line' version).

Perlicki, Krzysztof; Beblowska, Maria; Kruszewski, Jerzy

1995-06-01

198

Large core fiber optic cleaver  

Energy Technology Data Exchange (ETDEWEB)

The present invention relates to a device and method for cleaving optical fibers which yields cleaved optical fiber ends possessing high damage threshold surfaces. The device can be used to cleave optical fibers with core diameters greater than 400 .mu.m.

Halpin, John M. (Livermore, CA)

1996-01-01

199

Aerogel-clad optical fiber  

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-01-01

200

Radiation hardness of optical fibers  

International Nuclear Information System (INIS)

Optical fibers of silica and plastic composition are rendered relatively stable to nuclear radiation induced optical losses by preirradiating with a high initial radiation dosage. Subsequent exposure of the radiation hardended fibers produce substantially lower radiation induced optical loss and faster fiber transmission recovery rates

1980-01-01

 
 
 
 
201

Interferometric Fiber-Optic Sensors.  

Science.gov (United States)

The article discusses the principles and performance of fiber-optic laser doppler velocimeters (LDVs) and fiber-optic gyroscopes developed and marketed by Mitsubishi Electric. The fiber-optic LDVs use He-Ne or Ar laser units already developed as light sou...

K. Kyuma S. Tai M. Nunoshita M. Fukuda T. Nagao

1984-01-01

202

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2012-01-01

203

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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, we review two kinds o...

Zhu, Tao; Wu, Di; Liu, Min; Duan, De-wen

2012-01-01

204

In-fiber integrated chemiluminiscence online optical fiber sensor.  

Science.gov (United States)

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

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

2013-09-01

205

Nonlinear fiber optics  

CERN Document Server

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

Agrawal, Govind

2012-01-01

206

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

Science.gov (United States)

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

Nishiyama, Michiko; Sasaki, Hiroyuki; Watanabe, Kazuhiro

2007-05-01

207

New concepts for fiber optic position sensors  

Science.gov (United States)

Digital or ladar fiber optic position sensors may be a promising alternative to electrical LVDT or RVDT for aeronautics. They are rugged devices, they do not need some form of referencing to avoid any error arising from random in-line loss, and they give absolute measurement results. Besides they are to date, the sensors which are the most advanced in tests for aeronautical applications. In this paper we present new concepts for these sensors which make them easier to implement on an aircraft. One of these ideas consists in referencing the optical fiber length from the emitter/receiver to the ladar sensing head, thus making the sensor acquisition independent of the optical fiber length. The other principles which are discussed in this paper concern digital fiber optic sensors. The second concept consists in adding a checksum to each position encoding word in order to test if the measure is valid or not. At last we propose a specific quantization law.

Perraud, Eric

1993-02-01

208

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

1981-01-01

209

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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. T...

Mustapha Remouche; Francis Georges; Patrick Meyrueis

2013-01-01

210

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

Science.gov (United States)

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.

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

1988-01-01

211

Noncontact fiber optic micrometer  

Science.gov (United States)

A sensor instrument able to measuring the thickness of different semitransparent objects with a resolution of one micron is described. This is based on a fiber optic reflectometer and a laser autofocus system and permit to measuring the thickness of thin surfaces such as semiconductor films, plastic materials and semitransparent objects. The response time for the measuring was roughly 2 sec and the thickness results were compared with a digital mechanical micrometer and both are in good agreement.

Betancourt Ibarra, F.; Guajardo-Gonzalez, Candelario; Castillo-Guzman, Arturo; Guzman-Ramos, Valentin; Selvas, Romeo

2010-10-01

212

Optical fibers for FTTH application  

Science.gov (United States)

In this paper the specifics of FTTH (Fiber To The Home) networks in terms of requirements for optical fibers has been presented. Optical fiber samples used in FTTH applications acquired from the worldwide leading manufacturers were subjected to small diameter mandrel wraps tests. The detailed procedures of performed tests and the measurement results has been presented.

Guzowski, Bartlomiej; Tosik, Grzegorz; Lisik, Zbigniew; Bedyk, Michal; Kubiak, Andrzej

2013-07-01

213

Rapid determination of surfactant critical micelle concentration in aqueous solutions using fiber-optic refractive index sensing.  

Science.gov (United States)

We describe a simple and rapid method for determining the critical micelle concentration (CMC) of surfactants from fiber-optic measurements of refractive index. The refractive index of an aqueous surfactant solution was monitored as the surfactant concentration was increased using an automated dispensing system. On reaching the surfactant's CMC value, an abrupt change was observed in the rate of increase of the refractive index with increasing concentration. The measurement system provides rapid semiautomatic data collection and analysis, increasing the precision, sensitivity, and range of applicability of the technique while substantially decreasing the amount of manual intervention required. Measurements of CMC for sodium dodecyl sulfate (8.10mM), cetyltrimethylammonium chloride (1.58mM), and Triton X-100 (0.21mM) were in excellent agreement with values previously reported in the literature. The method is applicable to cationic, anionic, and nonionic surfactants, and it offers a facile, in situ, and sensitive means of detecting micelle formation over a broad range of CMC values larger than 10(-1)mM. PMID:20175982

Tan, Chun Hua; Huang, Zhen Jian; Huang, Xu Guang

2010-06-01

214

Fiber optic micro sensor for the measurement of tendon forces  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A fiber optic sensor developed for the measurement of tendon forces was designed, numerically modeled, fabricated, and experimentally evaluated. The sensor incorporated fiber Bragg gratings and micro-fabricated stainless steel housings. A fiber Bragg grating is an optical device that is spectrally sensitive to axial strain. Stainless steel housings were designed to convert radial forces applied to the housing into axial forces that could be sensed by the fiber Bragg grating. The metal housing...

Behrmann, Gregory P.; Hidler, Joseph; Mirotznik, Mark S.

2012-01-01

215

Fiber optic micro sensor for the measurement of tendon forces  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract A fiber optic sensor developed for the measurement of tendon forces was designed, numerically modeled, fabricated, and experimentally evaluated. The sensor incorporated fiber Bragg gratings and micro-fabricated stainless steel housings. A fiber Bragg grating is an optical device that is spectrally sensitive to axial strain. Stainless steel housings were designed to convert radial forces applied to the housing into axial forces that could be sensed by the fiber Bragg grating...

Behrmann Gregory P; Hidler Joseph; Mirotznik Mark S

2012-01-01

216

Optical Communication over Plastic Optical Fibers Integrated Optical Receiver Technology  

CERN Multimedia

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...

Atef, Mohamed

2013-01-01

217

Alining sleeve for optical fibers  

Science.gov (United States)

Sleeve for alining two optical fibers is made with precisely correct inside diameter by using section of fiber as mandrel. Because optical fiber is manufactured to very close tolerances, diameter of section serving as mandrel will be same as diameters of two fibers that are mated in butt joint inside sleeve. Result, determined by experiments, is loss of no more that 0.3 dB at joint.

Austin, K. L.

1981-01-01

218

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

International Nuclear Information System (INIS)

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

2013-10-01

219

Sensing characteristics of polymer highly birefringent side-hole fiber  

Science.gov (United States)

This paper presents the sensor characteristics of highly birefringent polymer side-hole optical fiber. The fiber core with greater refractive index was made of copolymer PMMA-PS, while the cladding of pure PMMA. The fabricated fiber showed relatively low losses of the order of 6 dB/m in the visible range. We measured several sensing characteristics in the fabricated fiber, including birefringence and polarimetric sensitivity to pressure and temperature. The fiber showed high polarimetric sensitivity to pressure, which is directly related to the presence of two large holes transferring symmetrical load applied to the cladding into nonsymmetric stress distribution in the core region. This in turn changes modal birefringence of the investigated fiber and increases the sensitivity to pressure.

Mergo, Pawe?; Klimek, Jacek; Skorupski, Krzysztof; Gasior, Katarzyna; Grzondko, Mateusz; Martynkien, Tadeusz; Wójcik, Grzegorz; Walewski, Aleksander; Pédzisz, Janusz; Kope?, Jaros?aw; Urba?czyk, Wac?aw

2013-07-01

220

Harnessing the fiber fuse for sensing applications.  

Science.gov (United States)

A simple refractive index sensor based on a small section of fiber damaged by the fiber fuse is proposed and demonstrated with a sensitivity of 350.58 nm/refractive index unit (RIU). For comparison, a hetero-core structure fiber sensor composed of a short no-core fiber (NCF) sandwiched between two pieces of single-mode fibers is demonstrated with a sensitivity of 157.29 nm/RIU. The fiber fuse technique can allow mass production of sensors by incorporating small sections of the damaged fiber of any type into each device. We believe this is the first application of the periodic damage tracks in optical fibers formed by the fiber fuse. PMID:24787785

Lin, Guei-Ru; Baiad, Mohamad Diaa; Gagne, Mathieu; Liu, Wen-Fung; Kashyap, Raman

2014-04-21

 
 
 
 
221

Infrared optical material and fibers V  

Energy Technology Data Exchange (ETDEWEB)

These proceedings collect papers on the subject of infrared optical fiber materials. Topics include: mechanical properties of IR fibers, optical properties of IR fibers, aging effects in extruded polycrystalline thallium bromo-iodide fibers, and IR waveguides.

Klocek, P.

1987-01-01

222

Advanced technique in fiber optic sensors  

Science.gov (United States)

There are a lot of optical sensors for the selective determination of ion species. Some organic compounds also have been determined by optical sensors using the enzymatic and immunological reactions. On the other hand, calixarenes are well known as novel host molecules, and specific guest ions or molecules can be incorporated inside the cavity of calixarenes. This specific recognition function of calixarene has been applied to the development of electrochemical and optical ion sensors. However, an optical sensing of organic molecules using this host-guest system is a new approach at present. In this study, a sensing membrane containing a fluorescent probe and a calixarene derivative is prepared, and it is attached on a distal end of an optical fiber. An organic compound, which specially interacts with the calixarene derivative, is optically determined. The response mechanism of the sensor is discussed.

Kawabata, Yuji; Yamashiro, T.; Imasaka, Totaro

1993-04-01

223

Optical-Fiber Leak Detector  

Science.gov (United States)

Proposed optical-fiber sensor detects small changes in pressure in elastomeric O-ring or similar pressure seal, which may indicate deterioration of seal and interpreted as indications of incipient failure. According to concept, length of optical fiber embedded in seal. Light-emitting diode illuminates one end of fiber; photodetector measures intensity of light emerging from other end. Pressure-induced changes in seal bend fiber slightly, altering microbending-induced loss of light from fiber and alter intensity of light at photodetector. Change in intensity approximately proportional to change in pressure.

Workman, Gary L.; Kosten, Susan E.

1994-01-01

224

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

Science.gov (United States)

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

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

2014-02-01

225

Fluorescing optical fibers and uses  

International Nuclear Information System (INIS)

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

1989-01-01

226

Latest advances in optical fibers  

Science.gov (United States)

Optical fibers can now be encountered anywhere in a telecommunication network. In that field, one of the major changes that occurred, at the turn of the Century, is the growing interest in Fiber-to-the-Home (FTTH) architectures, that is, optical fibers replacing copper in access networks to directly connect subscribers. This gave birth to a new category of single mode fibers referred to as bend-insensitive fibers, which has represented one of the major development focus of optical fiber manufacturers for the last 5 years. In parallel, key evolutions also took place in data communications with the decision to create, at the end of this decade, the next generation Ethernet hierarchy for equipment interfaces at rates of 40 and 100 Gb/s. This is driving recent research on fibers to be used to transport such high-rate signals between these equipments. To cite this article: L.-A. de Montmorillon et al., C. R. Physique 9 (2008).

de Montmorillon, Louis-Anne; Kuyt, Gerard; Nouchi, Pascale; Bertaina, Alain

2008-11-01

227

Optical fiber Fabry-Perot interferometer cavity fabricated by femtosecond laser micromachining and fusion splicing for refractive index sensing.  

Science.gov (United States)

We demonstrate a fiber in-line Fabry-Perot interferometer cavity sensor for refractive index measurement. The interferometer cavity is formed by drilling a micro-hole at the cleaved fiber end facet, followed by fusion splicing. A micro-channel is inscribed by femtosecond laser micromachining to vertically cross the cavity to allow liquid to flow in. The refractive index sensitivity obtained is ~994 nm/RIU (refractive index unit). Such a device is simple in configuration, easy for fabrication and reliable in operation due to extremely low temperature cross sensitivity of ~4.8 × 10(-6) RIU/°C. PMID:23037431

Liao, C R; Hu, T Y; Wang, D N

2012-09-24

228

Fiber-optic technology review  

International Nuclear Information System (INIS)

A history of fiber technology is presented. The advantages of fiber optics are discussed (bandwidth, cost, weight and size, nonmetallic construction and isolation). Some aspects of the disadvantages of fiber systems briefly discussed are fiber and cable availability, fiber components, radiation effects, receivers and transmitters, and material dispersion. Particular emphasis over the next several years will involve development of fibers and systems optimized for use at wavelengths near 1.3 ?m and development of wavelengths multiplexers for simultaneous system operation at several wavelengths

1980-03-25

229

Fiber-optic technology review  

Energy Technology Data Exchange (ETDEWEB)

A history of fiber technology is presented. The advantages of fiber optics are discussed (bandwidth, cost, weight and size, nonmetallic construction and isolation). Some aspects of the disadvantages of fiber systems briefly discussed are fiber and cable availability, fiber components, radiation effects, receivers and transmitters, and material dispersion. Particular emphasis over the next several years will involve development of fibers and systems optimized for use at wavelengths near 1.3 ..mu..m and development of wavelengths multiplexers for simultaneous system operation at several wavelengths.

Lyons, P.B.

1980-01-01

230

Fiber optic hydrogen sensor  

Energy Technology Data Exchange (ETDEWEB)

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).

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

1996-05-01

231

In-line fiber optic interferometric sensors in single-mode fibers.  

Science.gov (United States)

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, we review two kinds of typical in-line fiber optic interferometers formed in single-mode fibers fabricated with different post-processing techniques. Also, some recently reported specific technologies for fabricating such fiber optic interferometers are presented. PMID:23112608

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

2012-01-01

232

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

Directory of Open Access Journals (Sweden)

Full Text Available 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, we review two kinds of typical in-line fiber optic interferometers formed in single-mode fibers fabricated with different post-processing techniques. Also, some recently reported specific technologies for fabricating such fiber optic interferometers are presented.

De-Wen Duan

2012-08-01

233

Glass-clad semiconductor core optical fibers  

Science.gov (United States)

Glass-clad optical fibers comprising a crystalline semiconductor core have garnered considerable recent attention for their potential utility as novel waveguides for applications in nonlinear optics, sensing, power delivery, and biomedicine. As research into these fibers has progressed, it has become evident that excessive losses are limiting performance and so greater understanding of the underlying materials science, coupled with advances in fiber processing, is needed. More specifically, the semiconductor core fibers possess three performance-limiting characteristics that need to be addressed: (a) thermal expansion mismatches between crystalline core and glass cladding that lead to cracks, (b) the precipitation of oxide species in the core upon fiber cooling, which results from partial dissolution of the cladding glass by the core melt, and (c) polycrystallinity; all of which lead to scattering and increased transmission losses. This dissertation systematically studies each of these effects and develops both a fundamental scientific understanding of and practical engineering methods for reducing their impact. With respect to the thermal expansion mismatch and, in part, the dissolution of oxides, for the first time to our knowledge, oxide and non-oxide glass compositions are developed for a series of semiconductor cores based on two main design criteria: (1) matching the thermal expansion coefficient between semiconductor core and glass cladding to minimize cracking and (2) matching the viscosity-temperature dependences, such that the cladding glass draws into fiber at a temperature slightly above the melting point of the semiconductor in order to minimize dissolution and improve the fiber draw process. The x[Na 2O:Al2O3] + (100 - 2x)SiO2 glass compositional family was selected due to the ability to tailor the glass properties to match the aforementioned targets through slight variations in composition and adjusting the ratios of bridging and non-bridging oxygen; experimental results show a decrease in fiber core oxygen content in the fibers drawn with the tailored glass composition. In a further attempt to reduce the presence of oxide species in the core, a reactive molten core approach to semiconductor optical fibers are developed. Specifically, the addition of silicon carbide (SiC) into a silicon (Si) core provides an in-situ reactive getter of oxygen during the draw process to achieve oxygen-free silicon optical fibers. Elemental analysis and x-ray diffraction of fibers drawn using this reactive chemistry approach show negligible oxygen concentration in the highly crystalline silicon core, a significant departure from the nearly 18 atom percent oxygen in previous fibers. Scattering of light out of the core is shown qualitatively to have been reduced in the process. The role of the cross-sectional geometry on the resultant core crystallography with respect to the fiber axis is explored in a continued effort to better understand the nature of the crystal formation and structural properties in these semiconductor core optical fibers. A square cross-sectional geometry was explored to determine if core non-circularity can enhance or promote single crystallinity, as the semiconductors studied have a preference to form cubic crystals. Resultant crystallography of the non-circular core showed a significant improvement in maintaining a preferred crystallographic orientation, with the square core fibers exhibiting a 90% preference for the family of directions occurring closest to the longitudinal direction of the fiber. The ability to orient the crystallography with respect to the fiber axis could be of great value to future nonlinear optical fiber-based devices. In summary, this dissertation begins to elucidate some of the microstructural features, not present in conventional glass optical fibers, which could be important for future low-loss single crystalline semiconductor optical fibers. Additionally, this dissertation offers novel insight into the various aspects of mate

Morris, Stephanie Lynn

234

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 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

1995-04-01

235

Locally pressed photonic crystal fiber interferometer for multiparameter sensing.  

Science.gov (United States)

A mode interferometer consisting of a short section of photonic crystal fiber (PCF) fusion spliced to a standard single-mode optical fiber with localized perturbations is proposed for multiparameter sensing. In this sensing configuration, the parameter being sensed changes the visibility (an absolute parameter) of the interference pattern and also causes a shift (a relative parameter) to the interference pattern. To achieve this dual effect, a portion of the PCF is squeezed on localized regions with a serrated mechanical piece. In this manner, we introduce attenuation losses and effective refractive index changes to the interfering modes, hence, visibility changes and a shift to the interference pattern. Our device is suitable for monitoring diverse physical parameters, such as weight, lateral force, pressure, load, etc., with the advantage that compensation to temperature or power fluctuations is not required. Moreover, the sensor sensitivity can be adjusted in a simple manner. PMID:24784050

Villatoro, Joel; Minkovich, Vladimir P; Zubia, Joseba

2014-05-01

236

High Precision Displacement Measurement Using Fiber Optics  

CERN Document Server

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

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

2002-01-01

237

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)

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.

Farley, Douglas L.

2005-01-01

238

Optical active fiber parameters identification  

Science.gov (United States)

Erbium doped fiber is a basic element of an optical amplifier. The estimation of fiber parameters set is the main problem of designing its application. The knowledge of fiber core radius, the overlap factors representing the fraction of pump power and signal within the doped region, doping concentration and fiber glass type are necessary for this task. The problem is significant, because fiber producers do not print full data or the printed data do not agree with facts. The presented solution is their identification with typical printed and measured data using in mathematical model of quantum and wave optics. The elaborated method was tried on 3M active fiber samples, effects show that its correctness is about 15%.

Borecki, Michal; Kruszewski, Jerzy

2004-09-01

239

Ultra Low Loss Optical Fiber Cable Assemblies.  

Science.gov (United States)

Progress toward development of ruggedized ultra low loss (optical fiber cable assemblies consisting of six optical fibers is reported. Effort involves investigations of fiber, cabling, and connector development on an individual as well as comb...

R. Kopstein

1981-01-01

240

Ultra Low Optical Fiber Cable Assemblies.  

Science.gov (United States)

Progress toward development of ruggedized ultra low loss (optical fiber cable assemblies consisting of six optical fibers is reported. Effort involves investigations of fiber, cabling, and connector development on an individual as well as comb...

J. Smith X. Glavas R. Kopstein

1980-01-01

 
 
 
 
241

Beam Diagnostics with Optical Fiber Optics  

CERN Multimedia

Optical fiber has been widely used for communications. It is a waveguide with very high-frequency bandwidth. Therefore, it has broad applications for high-frequency related signals such as high-energy Accelerator beam signls. Research and developments has been done to measure charged particle beam and synchrotron radiation with optical fiber based instruments developed by the author. The paper will describe and discuss the experiments and testing of charged particle beams and synchrotron radiation that haverecently been performed.

Yin, Yan

2005-01-01

242

Bidirectional optical coupler for plastic optical fibers.  

Science.gov (United States)

We have developed a low-loss bidirectional optical coupler for high-speed optical communication with plastic optical fibers (POFs). The coupler, which is fabricated by an injection molding method that uses poly (methyl methacrylate), has an antisymmetric tapered shape. We show that the coupler has low insertion and branching losses. The tapered shape of the receiving branch reduces beam diameter and increases detection efficiency coupling to a photodetector, whose area is smaller than that of the plastic optical fiber. The possibility of more than 15-m bidirectional transmission with a signaling bit rate up to 500 Mbits/s for simplex step-index POFs is demonstrated. PMID:15929280

Sugita, Tatsuya; Abe, Tomiya; Hirano, Kouki; Itoh, Yuzo

2005-05-20

243

Longitudinal strain sensing with photonic crystal fibers and fiber Bragg gratings  

Science.gov (United States)

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

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

2014-03-01

244

Robust Mapping of Incoherent Fiber-Optic Bundles  

Science.gov (United States)

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.

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

2007-01-01

245

Optical fibers and their applications  

Energy Technology Data Exchange (ETDEWEB)

Fiber optics have become in the last few years an extremely attractive method of data transfer. A short review of their properties and of their applications is given, together with some feelings from personal experience of the author. (orig.).

Trasatti, L.

1989-07-01

246

Radiation damage in optical fibers  

International Nuclear Information System (INIS)

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

1983-04-11

247

Fracture analysis of optical fibers  

International Nuclear Information System (INIS)

The fracture markings on glass optical fiber surfaces are quantitatively related to the strength and time under load. Knowledge of the fracture-initiating defects and the surrounding topography pinpoints the source of failure, aids in troubleshooting, and improves production procedures. It is shown that the techniques of fracture surface analysis help analyze in-service failures as well as improve fiber optic production control

1980-03-27

248

Quantum cryptography using optical fibers.  

Science.gov (United States)

Quantum cryptography permits the transmission of secret information whose security is guaranteed by the uncertainty principle. An experimental system for quantum crytography is implemented based on the linear polarization of single photons transmitted by an optical fiber. Polarization-preserving optical fiber and a feedback loop are employed to maintain the state of polarization. Error rates of less than 0.5% are obtained. PMID:20885657

Franson, J D; Lives, H

1994-05-10

249

Fiber-Optic Distribution Of Pulsed Power To Multiple Sensors  

Science.gov (United States)

Optoelectronic systems designed according to time-sharing scheme distribute optical power to multiple integrated-circuit-based sensors in fiber-optic networks. Networks combine flexibility of electronic sensing circuits with advantage of electrical isolation afforded by use of optical fibers instead of electrical conductors to transmit both signals and power. Fiber optics resist corrosion and immune to electromagnetic interference. Sensor networks of this type useful in variety of applications; for example, in monitoring strains in aircraft, buildings, and bridges, and in monitoring and controlling shapes of flexible structures.

Kirkham, Harold

1996-01-01

250

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)

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.

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

2013-12-01

251

Towards biochips using microstructured optical fiber sensors  

DEFF Research Database (Denmark)

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

Rindorf, Lars Henning; Jensen, Jesper Bo

2006-01-01

252

Developments on high temperature fiber optic microphone  

Science.gov (United States)

A fiber optic microphone, based on the principle of the fiber optic lever, features small size, extended bandwidth, and capability to operate at high temperatures. These are requirements for measurements in hypersonic flow. This paper describes the principles of operation of fiber optic sensors, a discussion of the design of a fiber optic microphone, the functional elements and packaging techniques of the optoelectronic circuitry, and the calibration techniques used in the development of the high temperature fiber optic microphone.

Wright, Kenneth D., II; Zuckerwar, Allan J.

1992-01-01

253

Novel optical fiber ultrasonic sensor based on fiber laser  

Science.gov (United States)

Researching high-sensitivity flexible ultrasonic sensor is important in the field of structural health monitoring (SHM). In this research, a novel ultrasonic sensor based on fiber ring laser with an in-built phase shifted fiber Bragg grating (PSFBG) is proposed and demonstrated. The first function of the PS-FBG is to determine the wavelength of the laser. Thus, this sensing system is robust to temperature change and quasi-static strain change because the PS-FBG is always illuminated. The other function of the PS-FBG is a sensor with ultra-steep slope and short effective grating length. It is beneficial for achievement of high-sensitivity and broad-bandwidth ultrasonic detection. The experimental evaluated sensitivity was 58.5+/-3 dB, which is 7.5 dB higher than traditional PZT sensor. This may be the highest sensitivity obtained by optical fiber sensing system. Because of the advantages including robustness, simple structure and low cost in addition to the high sensitivity and broad bandwidth, this sensing system has potential practical applications in ultrasonic SHM.

Wu, Qi; Okabe, Yoji; Sun, Junqiang

2014-03-01

254

Nonlinear effects in optical fibers  

CERN Document Server

This book will provide insight into the principles and applications of nonlinear effects in fibers for students, researchers, and developers who have a basic understanding of electromagnetic theory under their belts.  It will explore the physics, limitations, applications, and research results surrounding nonlinear effects in fiber optics. In addition to communications, optical fibers are already used in medical procedures, automobiles, and aircraft and are expected to have many other applications.  This will expand the range of industry workers who will find a book of this type useful.

Ferreira, Mario F

2011-01-01

255

Supercontinuum Generation in Optical Fibers  

Science.gov (United States)

1. Introduction and history J. R. Taylor; 2. Supercontinuum generation in microstructure fiber - an historical note J. K. Ranka; 3. Nonlinear fiber optics overview J. C. Travers, M. H. Frosz and J. M. Dudley; 4. Fiber supercontinuum generation overview J. M. Dudley; 5. Silica fibers for supercontinuum generation J. C. Knight and W. Wadsworth; 6. Supercontinuum generation and nonlinearity in soft glass fibers J. H. V. Price and D. J. Richardson; 7. Increasing the blue-shift of a picosecond pumped supercontinuum M. H. Frosz, P. M. Moselund, P. D. Rasmussen, C. L. Thomsen and O. Bang; 8. Continuous wave supercontinuum generation J. C. Travers; 9. Theory of supercontinuum and interactions of solitons with dispersive waves D. V. Skryabin and A. V. Gorbach; 10. Interaction of four-wave mixing and stimulated Raman scattering in optical fibers S. Coen, S. G. Murdoch and F. Vanholsbeeck; 11. Nonlinear optics in emerging waveguides: revised fundamentals and implications S. V. Afshar, M. Turner and T. M. Monro; 12. Supercontinuum generation in dispersion varying fibers G. Genty; 13. Supercontinuum generation in chalcogenide glass waveguides Dong-Il Yeom, M. R. E. Lamont, B. Luther Davies and B. J. Eggleton; 14. Supercontinuum generation for carrier-envelope phase stabilization of mode-locked lasers S. T. Cundiff; 15. Biophotonics applications of supercontinuum generation C. Dunsby and P. M. W. French; 16. Fiber sources of tailored supercontinuum in nonlinear microspectroscopy and imaging A. M. Zheltikov; Index.

Dudley, J. M.; Taylor, J. R.

2010-04-01

256

Achromatic optical diode in fiber optics  

CERN Document Server

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.

Berent, Michal; Vitanov, Nikolay V

2013-01-01

257

A fiber-optic polarimetric demonstration kit  

International Nuclear Information System (INIS)

A simple and multifunctional fiber-optic polarimetric kit on the basis of highly birefringent single-mode fibers is presented. The fiber-optic polarimetric kit allows us to perform the following laboratory exercises: (i) fiber excitation and the measurement of numerical aperture, (ii) polarization preservation and (iii) obtain polarization-sensitive fiberized interferometers.

2012-05-01

258

Fiber optic fire detection technology  

International Nuclear Information System (INIS)

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

1990-02-20

259

Potting techniques for fiber optical couplers  

Science.gov (United States)

A coupler for coupling light from one single mode optical fiber to another. Two or more optical fibers are provide in twisted or braided adjacency so that the evanescent field of one optical fiber is coupled into at least one other fiber for dividing the power therebetween. Means are provided for coextensively supporting and encapsulating the optical fibers to stabilize and protect them under demanding environmental conditions resulting from temperature variations, physical shock and vibration.

Giallorenzi, T. G.

1986-06-01

260

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

Directory of Open Access Journals (Sweden)

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

Lai-Kwan Chau

2009-08-01

 
 
 
 
261

Fiber optic crossbar switch for automatically patching optical signals  

Science.gov (United States)

A system for automatically optically switching fiber optic data signals between a plurality of input optical fibers and selective ones of a plurality of output fibers is described. The system includes optical detectors which are connected to each of the input fibers for converting the optic data signals appearing at the respective input fibers to an RF signal. A plurality of RF to optical signal converters are arranged in rows and columns. The output of each of the optical detectors are each applied to a respective row of optical signal converted for being converters back to an optical signal when the particular optical signal converter is selectively activated by a dc voltage.

Bell, C. H. (inventor)

1983-01-01

262

Fiber optic pressure sensors in skin-friction measurements  

Science.gov (United States)

A fiber optic lever sensing technique that can be used to measure normal pressure as well as shear stresses is discussed. This method uses three unequal fibers combining small size and good sensitivity. Static measurements appear to confirm the theoretical models predicted by geometrical optics and dynamic tests performed at frequencies up to 10 kHz indicate a flat response within this frequency range. These sensors are intended for use in a low speed wind tunnel environment.

Cuomo, F. W.

1986-01-01

263

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

Directory of Open Access Journals (Sweden)

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.

Bongsoo Lee

2011-10-01

264

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

1988-01-27

265

Thick Film Fiber Optics to Integrated Optics Interface.  

Science.gov (United States)

Thick film optical waveguides have been integrated with mechanical fiber optics connectors on a single substrate. Micron alignment accuracies are possible by photo-lithographically fabricating the mechanical fiber guides in the same medium as the optical ...

I. Aeby

1979-01-01

266

Scintillating optical fibers in mammography  

International Nuclear Information System (INIS)

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

1996-11-21

267

A Smart Graded-index Multimode Fiber Based Sensor Unit for Multi-parameter Sensing Applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We demonstrate a smart optical fiber sensor unit to realize a multi-parameter sensing, including temperature, curvature and strain or displacement. The sensor unit is composed of a Bragg grating in graded-index multimode fiber and a Fizeau cavity.

Shuo Fang; Baoyong Li; Dawei Song; Jianzhong (Charlie) Zhang; Weimin Sun; Libo Yuan

2013-01-01

268

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 w...

Wook Jae Yoo; Kyoung Won Jang; Jeong Ki Seo; Jinsoo Moon; Ki-Tek Han; Jang-Yeon Park; Byung Gi Park; Bongsoo Lee

2011-01-01

269

Integrated optics for fiber gyro's  

Science.gov (United States)

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.

Goss, W.; Goldstein, R.

1983-01-01

270

Optical sensor based on two in-series birefringent optical fibers.  

Science.gov (United States)

An optical fiber sensor based on the combination of two spliced birefringent optical fiber sections is proposed in this paper. The sensor is built up in a Solc-filter-like configuration and a simple theoretical model based on Jones matrices is employed to predict experimental results. By choosing the suitable birefringent optical fibers (e.g., photonic crystal fibers, birefringent microfibers, elliptical core fibers, PANDA fibers, etc.), the sensor described herein allows for probing of two physical parameters (e.g., refractive index and temperature, hydrostatic pressure and temperature) or sensing the same parameter in two disconnected environments. In order to demonstrate the sensor performance, the system response was evaluated in a temperature-sensing measurement. PMID:23852207

Osório, Jonas H; Cordeiro, Cristiano M B

2013-07-10

271

High-performance hybrid Raman/fiber Bragg grating fiber-optic sensor based on simplex cyclic pulse coding.  

Science.gov (United States)

We propose and experimentally demonstrate the use of cyclic pulse coding to improve the performance of hybrid Raman/fiber Bragg grating (FBG) fiber-optic sensors, for simultaneous measurement of distributed static temperature and discrete dynamic strain over the same sensing fiber. Effective noise reduction is achieved in both Raman optical time-domain reflectometry and dynamic interrogation of time-division-multiplexed fiber FBG sensors, enhancing the sensing range resolution and providing real-time point dynamic strain measurement capabilities. The highly integrated sensor scheme employs broadband apodized low-reflectivity FBGs, a single narrowband optical source, and a shared receiver block. PMID:23455106

Taki, M; Zaidi, F; Toccafondo, I; Nannipieri, T; Signorini, A; Faralli, S; Di Pasquale, F

2013-02-15

272

Recent progress in distributed fiber optic sensors.  

Science.gov (United States)

Rayleigh, Brillouin and Raman scatterings in fibers result from the interaction of photons with local material characteristic features like density, temperature and strain. For example an acoustic/mechanical wave generates a dynamic density variation; such a variation may be affected by local temperature, strain, vibration and birefringence. By detecting changes in the amplitude, frequency and phase of light scattered along a fiber, one can realize a distributed fiber sensor for measuring localized temperature, strain, vibration and birefringence over lengths ranging from meters to one hundred kilometers. Such a measurement can be made in the time domain or frequency domain to resolve location information. With coherent detection of the scattered light one can observe changes in birefringence and beat length for fibers and devices. The progress on state of the art technology for sensing performance, in terms of spatial resolution and limitations on sensing length is reviewed. These distributed sensors can be used for disaster prevention in the civil structural monitoring of pipelines, bridges, dams and railroads. A sensor with centimeter spatial resolution and high precision measurement of temperature, strain, vibration and birefringence can find applications in aerospace smart structures, material processing, and the characterization of optical materials and devices. PMID:23012508

Bao, Xiaoyi; Chen, Liang

2012-01-01

273

Recent Progress in Distributed Fiber Optic Sensors  

Directory of Open Access Journals (Sweden)

Full Text Available Rayleigh, Brillouin and Raman scatterings in fibers result from the interaction of photons with local material characteristic features like density, temperature and strain. For example an acoustic/mechanical wave generates a dynamic density variation; such a variation may be affected by local temperature, strain, vibration and birefringence. By detecting changes in the amplitude, frequency and phase of light scattered along a fiber, one can realize a distributed fiber sensor for measuring localized temperature, strain, vibration and birefringence over lengths ranging from meters to one hundred kilometers. Such a measurement can be made in the time domain or frequency domain to resolve location information. With coherent detection of the scattered light one can observe changes in birefringence and beat length for fibers and devices. The progress on state of the art technology for sensing performance, in terms of spatial resolution and limitations on sensing length is reviewed. These distributed sensors can be used for disaster prevention in the civil structural monitoring of pipelines, bridges, dams and railroads. A sensor with centimeter spatial resolution and high precision measurement of temperature, strain, vibration and birefringence can find applications in aerospace smart structures, material processing, and the characterization of optical materials and devices.

Xiaoyi Bao

2012-06-01

274

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)

2011-01-01

275

Localized strain sensing with fiber Bragg-grating ring cavities.  

Science.gov (United States)

We report the theoretical description and the experimental demonstration of an optical resonator formed by inserting a Fiber Bragg Grating (FBG) in a closed fiber loop. The spectral characteristics of such a resonator strongly depend on the reflectivity of the FBG. In the wavelength region where the FBG reflectivity R is negligible, the system behaves like a conventional ring resonator. On the other hand, when R is not vanishing, a split-mode structure can be observed, associated to the degeneracy removal of two counterpropagating resonant modes. The magnitude of the mode splitting can be used to sense small variations of the FBG physical parameters, such as length, temperature or group index. An example of strain sensing with this setup is reported, showing that the mode splitting is sensitive to a mechanical strain applied to the FBG, while it is almost insensitive to a strain applied to any other point of the resonator. This peculiar feature allows to perform cavity-enhanced, local strain measurements with a reduced sensitivity to environmental perturbations, which represents an important improvement in the framework of the fiber-optic sensors. PMID:24514497

Campanella, C E; Giorgini, A; Avino, S; Malara, P; Zullo, R; Gagliardi, G; De Natale, P

2013-12-01

276

Fiber optic probes for biomedical optical spectroscopy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Optical spectroscopy has been well validated by the physical sciences as a method to characterize chemical compositions in biological material. It has also showed promising to detect atherosclerotic plaques, which can form in the coronary artery walls, and cause heart attacks and strokes. This project seeks to optimize and build fiber optic probes for diffuse reflectance and fluorescence spectroscopy which can assess these plaques. A side-viewing probe is particularly advantageous in t...

Bru, Jørgen

2008-01-01

277

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

DEFF Research Database (Denmark)

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 α-streptavidin and Cy5-labelled α-CRP antibodies is demonstrated.

Emiliyanov, Grigoriy Andreev; Høiby, Poul E.

2013-01-01

278

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

Emiliyanov, Grigoriy; Høiby, Poul E.; Pedersen, Lars H.; Bang, Ole

2013-01-01

279

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

Directory of Open Access Journals (Sweden)

Full Text Available We have developed a fluorescence-based fiber-optical biosensor, which can selectively detect different antibodies in serial at preselected positions inside a single piece of fiber. The fiber is a microstructured polymer optical fiber fabricated from TOPAS cyclic olefin copolymer, which allows for UV activation of localized sensor layers inside the holes of the fiber. Serial fluorescence-based selective sensing of Cy3-labelled ?-streptavidin and Cy5-labelled ?-CRP antibodies is demonstrated.

Lars H. Pedersen

2013-03-01

280

Plastic optical fibers in sensors: a review  

Science.gov (United States)

Basic properties of thermoplastic optical fibers are described. Resulting possibilities and limitations of polymer fiber use in optical sensors are discussed. As an example the idea of the integrated alarm system head, containing smoke, temperature and humidity sensors, is shown.

Kruszewski, Jerzy; Borecki, Michal; Beblowska, Maria

2004-09-01

 
 
 
 
281

Fabrication Quality Analysis of a Fiber Optic Refractive Index Sensor Created by CO2 Laser Machining  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study investigates the CO2 laser-stripped partial cladding of silica-based optic fibers with a core diameter of 400 ?m, which enables them to sense the refractive index of the surrounding environment. However, inappropriate treatments during the machining process can generate a number of defects in the optic fiber sensors. Therefore, the quality of optic fiber sensors fabricated using CO2 laser machining must be analyzed. The results show that analysis of the fiber core size after machi...

Chien-Hsing Chen; Bo-Kuan Yeh; Jaw-Luen Tang; Wei-Te Wu

2013-01-01

282

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

1994-01-01

283

Sealed fiber-optic bundle feedthrough  

Energy Technology Data Exchange (ETDEWEB)

A sealed fiber-optic bundle feedthrough by which a multitude of fiber-optic elements may be passed through an opening or port in a wall or structure separating two environments at different pressures or temperatures while maintaining the desired pressure or temperature in each environment. The feedthrough comprises a rigid sleeve of suitable material, a bundle of individual optical fibers, and a resin-based sealing material that bonds the individual optical fibers to each other and to the rigid sleeve.

Tanner, Carol E. (Niles, MI)

2002-01-01

284

Applications of fiber optics in physical protection  

Energy Technology Data Exchange (ETDEWEB)

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.

Buckle, T.H. [Sandia National Labs., Albuquerque, NM (United States)

1994-03-01

285

High pressure fiber optic sensor system  

Energy Technology Data Exchange (ETDEWEB)

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.

Guida, Renato; Xia, Hua; Lee, Boon K; Dekate, Sachin N

2013-11-26

286

Interferometric fiber-optic bending / nano-displacement sensor using plastic dual-core fiber  

CERN Document Server

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.

Qu, H; Skorobogatiy, M

2014-01-01

287

Multiple object fiber optic spectroscopy  

Science.gov (United States)

The Steward Observatory of the University of Arizona employs short optical fiber lengths to bring light from galaxy images at the 2.3 m telescope's focus to a line along a spectrograph slit, thereby obtaining simultaneous spectra of many objects of the field of view. After describing this instrument, attention is given to the development of an improved version through which efficiency gains will be obtained by remotely positioning the fibers under computer control and by correctly matching fiber outputs to the spectrograph optics. A CCD will replace the presently employed image tube and photographic plate detector system, in order to permit sky subtraction, yield increased dynamic range, and provide more accurate wavelength calibration due to the detector's fixed format.

Hill, J. M.; Angel, J. R. P.; Scott, J. S.; Lindley, D.; Hintzen, P.

1982-01-01

288

Fiber Optic System for Measuring Electric Fields.  

Science.gov (United States)

A fiber optic sensor system and associated technique is disclosed for measuring an electric field wherein a sensor arm of optical fiber cable is wound about a core member of piezoelectric material. A reference arm of optical fiber cable substantially equa...

L. C. Bobb

1982-01-01

289

Alterable magnetic gratings for fiber optic switching  

Science.gov (United States)

Optical mode switching of fiber light can enhance the capability of fiber optic communications systems by eliminating opto-electronic-opto converters at switching nodes and by performing the switching even on crosstalk-prone high data rate channels. During this program several aspects of the stripe domain alterable grating were studied in a fiber optic switch mode.

Sauter, G. F.; Krawczak, J. A.; Nelson, G. L.; Hewitt, F. G.

1982-12-01

290

Fiber optic bundle array wide field-of-view optical receiver for free space optical communications.  

Science.gov (United States)

We propose a design for a free space optical communications (FSOC) receiver terminal that offers an improved field of view (FOV) in comparison to conventional FSOC receivers. The design utilizes a microlens to couple the incident optical signal into an individual fiber in a bundle routed to remote optical detectors. Each fiber in the bundle collects power from a solid angle of space; utilizing multiple fibers enhances the total FOV of the receiver over typical single-fiber designs. The microlens-to-fiber-bundle design is scalable and modular and can be replicated in an array to increase aperture size. The microlens is moved laterally with a piezoelectric transducer to optimize power coupling into a given fiber core in the bundle as the source appears to move due to relative motion between the transmitter and receiver. The optimum position of the lens array is determined via a feedback loop whose input is derived from a position sensing detector behind another lens. Light coupled into like fibers in each array cell is optically combined (in fiber) before illuminating discrete detectors. PMID:21042349

Hahn, Daniel V; Brown, David M; Rolander, Nathan W; Sluz, Joseph E; Venkat, Radha

2010-11-01

291

A reliable, sensitive and fast optical fiber hydrogen sensor based on surface plasmon resonance :  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report for the first time on the experimental response of a Surface Plasmon Resonance fiber optic sensor based on wavelength modulation for hydrogen sensing. This approach of measuring the hydrogen concentration makes the sensor insensitive to intensity fluctuations. The intrinsic fiber sensor developed provides remote sensing and enables the possibility of multi-points sensing. The sensor consists of a multilayer of 35 nm Au / 180 nm SiO2/ Pd deposited on a step- index multimode fiber cor...

Perrotton, C.; Westerwaal, R. J.; Javahiraly, N.; Slaman, M.; Schreuders, H.; Dam, B.; Meyrueis, P.

2013-01-01

292

Advanced fiber optic seismic sensors (geophone) research  

Science.gov (United States)

The systematical research on the fiber optic seismic sensors based on optical Fiber Bragg Grating (FBG) sensing technology is presented in this thesis. Optical fiber sensors using fiber Bragg gratings have a number of advantages such as immunity to electromagnetic interference, lightweight, low power consumption. The FBG sensor is intrinsically sensitive to dynamic strain signals and the strain sensitivity can approach sub micro-strain. Furthermore, FBG sensors are inherently suited for multiplexing, which makes possible networked/arrayed deployment on a large scale. The basic principle of the FBG geophone is that it transforms the acceleration of ground motion into the strain signal of the FBG sensor through mechanical design, and after the optical demodulation generates the analog voltage output proportional to the strain changes. The customized eight-channel FBG seismic sensor prototype is described here which consists of FBG sensor/demodulation grating pairs attached on the spring-mass mechanical system. The sensor performance is evaluated systematically in the laboratory using the conventional accelerometer and geophone as the benchmark, Two major applications of FBG seismic sensor are demonstrated. One is in the battlefield remote monitoring system to detect the presence of personnel, wheeled vehicles, and tracked vehicles. The other application is in the seismic reflection survey of oilfield exploration to collect the seismic waves from the earth. The field tests were carried out in the air force base and the oilfield respectively. It is shown that the FBG geophone has higher frequency response bandwidth and sensitivity than conventional moving-coil electromagnetic geophone and the military Rembass-II S/A sensor. Our objective is to develop a distributed FBG seismic sensor network to recognize and locate the presence of seismic sources with high inherent detection capability and a low false alarm rate in an integrated system.

Zhang, Yan

293

Extrinsic fiber-optic Fabry-Perot interferometer sensor for refractive index measurement of optical glass.  

Science.gov (United States)

A simple fiber-optic sensor based on Fabry-Perot interference for refractive index measurement of optical glass is investigated both theoretically and experimentally. A broadband light source is coupled into an extrinsic fiber Fabry-Perot cavity formed by the surfaces of a sensing fiber end and the measured sample. The interference signals from the cavity are reflected back into the same fiber. The refractive index of the sample can be obtained by measuring the contrast of the interference fringes. The experimental data meet with the theoretical values very well. The proposed technique is a new method for glass refractive index measurement with a simple, solid, and compact structure. PMID:20935706

Chen, Ji-Huan; Zhao, Jia-Rong; Huang, Xu-Guang; Huang, Zhen-Jian

2010-10-10

294

Interferometric fiber optic displacement sensor  

Energy Technology Data Exchange (ETDEWEB)

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. 23 figs.

Farah, J.

1999-04-06

295

Interferometric fiber optic displacement sensor  

Energy Technology Data Exchange (ETDEWEB)

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. 29 figs.

Farah, J.

1995-05-30

296

The power of fiber optics  

Energy Technology Data Exchange (ETDEWEB)

The latest technology in optical groundwire (OPGW), involving a single cable serving as a communications network, providing high-speed data and voice transmission, and as a conventional groundwire, part of a power transmission grid, is described. The first-ever symposium devoted to OPGW was held at Hydro-Quebec`s IREQ facility in Montreal, a fitting venue, considering that Hydro-Quebec has installed an extensive network of some 3,500 km of OPGW cables since 1992. The international symposium was attended by over 130 interested experts mainly from North America, but with delegates as far away as Australia, Japan, Libya, Brazil and the UK. The three-day event showcased a number of presentations and demonstrations concerning OPGW splicing requirements, the live-line installation process, the merits of using fiber optics in a power situation, comparison of international standards in OPGW and fiber optics applications, and future developments in fiber optics technology. Demonstration of IREQ`s OPGW type-testing and manufacturer`s exhibits provided an opportunity for hands-on experience.

Roy, C.

1999-03-01

297

Optical fiber temperature sensors: applications in heat treatments for foods  

Science.gov (United States)

Heat treatments are important methods to provide safe foods. Conventional heat treatments involve the application of steam and recently microwave treatments have been studied and applied as they are considered as fast, clean and efficient. Optical fiber sensing is an excellent tool to measure the temperature during microwave treatments. This paper shows the application of optical fiber temperature sensing during the heat treatment of different foods such as vegetables (jalapeño pepper and cilantro), cheese and ostrich meat. Reaching the target temperature, important bacteria were inactivated: Salmonella, Listeria and Escherichia coli. Thus, the use of optical fiber sensors has resulted be a useful way to develop protocols to inactivate microorganisms and to propose new methods for food processing.

Sosa-Morales, María Elena; Rojas-Laguna, Roberto; López-Malo, Aurelio

2010-10-01

298

Fabrication of a Porous Fiber Cladding Material Using Microsphere Templating for Improved Response Time with Fiber Optic Sensor Arrays  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A highly porous optical-fiber cladding was developed for evanescent-wave fiber sensors, which contains sensor molecules, maintains guiding conditions in the optical fiber, and is suitable for sensing in aqueous environments. To make the cladding material (a poly(ethylene) glycol diacrylate (PEGDA) polymer) highly porous, a microsphere templating strategy was employed. The resulting pore network increases transport of the target analyte to the sensor molecules located in the cladding, which im...

Henning, Paul E.; Rigo, M. Veronica; Geissinger, Peter

2012-01-01

299

Wavefront sensing reveals optical coherence  

CERN Document Server

Wavefront sensing is a set of techniques providing efficient means to ascertain the shape of an optical wavefront or its deviation from an ideal reference. Due to its wide dynamical range and high optical efficiency, the Shack-Hartmann is nowadays the most widely used of these sensors. Here, we show that it actually performs a simultaneous measurement of position and angular spectrum of the incident radiation and, therefore, when combined with tomographic techniques previously developed for quantum information processing, the Shack-Hartmann can be instrumental in reconstructing the complete coherence properties of the signal. We confirm these predictions with an experimental characterization of partially coherent vortex beams, a case that cannot be treated with the standard tools. This seems to indicate that classical methods employed hitherto do not fully exploit the potential of the registered data.

Stoklasa, B; Rehacek, J; Hradil, Z; Sanchez-Soto, L L

2014-01-01

300

Wavefront sensing reveals optical coherence  

Science.gov (United States)

Wavefront sensing is a set of techniques providing efficient means to ascertain the shape of an optical wavefront or its deviation from an ideal reference. Owing to its wide dynamical range and high optical efficiency, the Shack-Hartmann wavefront sensor is nowadays the most widely used of these sensors. Here we show that it actually performs a simultaneous measurement of position and angular spectrum of the incident radiation and, therefore, when combined with tomographic techniques previously developed for quantum information processing, the Shack-Hartmann wavefront sensor can be instrumental in reconstructing the complete coherence properties of the signal. We confirm these predictions with an experimental characterization of partially coherent vortex beams, a case that cannot be treated with the standard tools. This seems to indicate that classical methods employed hitherto do not fully exploit the potential of the registered data.

Stoklasa, B.; Motka, L.; Rehacek, J.; Hradil, Z.; Sánchez-Soto, L. L.

2014-02-01

 
 
 
 
301

Distributed fiber optic fuel leak detection system  

Science.gov (United States)

With the increase worldwide demand for hydrocarbon fuels and the vast development of new fuel production and delivery infrastructure installations around the world, there is a growing need for reliable fuel leak detection technologies to provide safety and reduce environmental risks. Hydrocarbon leaks (gas or liquid) pose an extreme danger and need to be detected very quickly to avoid potential disasters. Gas leaks have the greatest potential for causing damage due to the explosion risk from the dispersion of gas clouds. This paper describes progress towards the development of a fast response, high sensitivity, distributed fiber optic fuel leak detection (HySensTM) system based on the use of an optical fiber that uses a hydrocarbon sensitive fluorescent coating to detect the presence of fuel leaks present in close proximity along the length of the sensor fiber. The HySenseTM system operates in two modes, leak detection and leak localization, and will trigger an alarm within seconds of exposure contact. The fast and accurate response of the sensor provides reliable fluid leak detection for pipelines, tanks, airports, pumps, and valves to detect and minimize any potential catastrophic damage.

Mendoza, Edgar; Kempen, C.; Esterkin, Yan; Sun, Sunjian

2013-05-01

302

Fiber Optic Pressure Sensor using Multimode Interference  

International Nuclear Information System (INIS)

Based on the theory of multimode interference (MMI) and self-image formation, we developed a novel intrinsic optical fiber pressure sensor. The sensing element consists of a section of multimode fiber (MMF) without cladding spliced between two single mode fibers (SMF). The MMI pressure sensor is based on the intensity changes that occur in the transmitted light when the effective refractive index of the MMF is changed. Basically, a thick layer of Polydimethylsiloxane (PDMS) is placed in direct contact with the MMF section, such that the contact area between the PDMS and the fiber will change proportionally with the applied pressure, which results in a variation of the transmitted light intensity. Using this configuration, a good correlation between the measured intensity variations and the applied pressure is obtained. The sensitivity of the sensor is 3 ?V/psi, for a range of 0-60 psi, and the maximum resolution of our system is 0.25 psi. Good repeatability is also observed with a standard deviation of 0.0019. The key feature of the proposed pressure sensor is its low fabrication cost, since the cost of the MMF is minimal.

2011-01-01

303

Fiber Optic Pressure Sensor using Multimode Interference  

Energy Technology Data Exchange (ETDEWEB)

Based on the theory of multimode interference (MMI) and self-image formation, we developed a novel intrinsic optical fiber pressure sensor. The sensing element consists of a section of multimode fiber (MMF) without cladding spliced between two single mode fibers (SMF). The MMI pressure sensor is based on the intensity changes that occur in the transmitted light when the effective refractive index of the MMF is changed. Basically, a thick layer of Polydimethylsiloxane (PDMS) is placed in direct contact with the MMF section, such that the contact area between the PDMS and the fiber will change proportionally with the applied pressure, which results in a variation of the transmitted light intensity. Using this configuration, a good correlation between the measured intensity variations and the applied pressure is obtained. The sensitivity of the sensor is 3 {mu}V/psi, for a range of 0-60 psi, and the maximum resolution of our system is 0.25 psi. Good repeatability is also observed with a standard deviation of 0.0019. The key feature of the proposed pressure sensor is its low fabrication cost, since the cost of the MMF is minimal.

Ruiz-Perez, V I; Sanchez-Mondragon, J J [INAOE, Apartado Postal 51 y 216, Puebla 72000 (Mexico); Basurto-Pensado, M A [CIICAp, Universidad Autonoma del Estado de Morelos (Mexico); LiKamWa, P [CREOL, University of Central Florida, Orlando, FL 32816 (United States); May-Arrioja, D A, E-mail: iruiz@inaoep.mx, E-mail: mbasurto@uaem.mx, E-mail: delta_dirac@hotmail.com, E-mail: daniel_may_arrioja@hotmail.com [UAT Reynosa Rodhe, Universidad Autonoma de Tamaulipas (Mexico)

2011-01-01

304

Quantum limited particle sensing in optical tweezers  

International Nuclear Information System (INIS)

Particle sensing in optical tweezers systems provides information on the position, velocity, and force of the specimen particles. The conventional quadrant detection scheme is applied ubiquitously in optical tweezers experiments to quantify these parameters. In this paper, we show that quadrant detection is nonoptimal for particle sensing in optical tweezers and propose an alternative optimal particle sensing scheme based on spatial homodyne detection. A formalism for particle sensing in terms of transverse spatial modes is developed and numerical simulations of the efficacies of both quadrant and spatial homodyne detection are shown. We demonstrate that 1 order of magnitude improvement in particle sensing sensitivity can be achieved using spatial homodyne over quadrant detection.

2009-12-01

305

A Highly Sensitive Fiber Optic Sensor Based on Two-Core Fiber for Refractive Index Measurement  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A simple and compact fiber optic sensor based on a two-core fiber is demonstrated for high-performance measurements of refractive indices (RI) of liquids. In order to demonstrate the suitability of the proposed sensor to perform high-sensitivity sensing in a variety of applications, the sensor has been used to measure the RI of binary liquid mixtures. Such measurements can accurately determine the salinity of salt water solutions, and detect the water content of adulterated alcoholic beverage...

José Rafael Guzmán-Sepúlveda; Rafael Guzmán-Cabrera; Miguel Torres-Cisneros; José Javier Sánchez-Mondragón; Daniel Alberto May-Arrioja

2013-01-01

306

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.

2012-09-01

307

Utilization of fiber optics in radiation diagnostics  

International Nuclear Information System (INIS)

Fiber optics can provide a cost effective transmission medium for wide bandwidth radiation diagnostics. Passive systems have been investigated which allow conversion of radiation energy to optical energy with direct coupling to optical fibers. Organic scintillators have been developed which emit at wavelengths near 600 nm. The new scintillators yield a FWHM below 1.5 ns. The scintillator emission band is very broad, leading to the requirement of optical filtering to limit material dispersion in the fiber. Trade-offs involving fiber length, dynamic range, fiber radiation damage, scintillator radiation damage, bandwidth, and spectral filter width are discussed

1978-09-08

308

Photonic crystal fiber modal interferometer for refractive index sensing of glycerine solution  

Science.gov (United States)

A photonic crystal fiber sensor was prepared for refractive index sensing. Based on modal interferometer theory, the relationships between the refractive index of glycerine solution and resonant wavelength shift of the sensor are analyzed by numerical simulation. A fiber optical device was designed to operate the sensing experiment. The sensing experiment shows that the resonant wavelength blued-shift for the sensor with refractive index in the range of 1.33~1.41 happens when increasing glycerine solution from 0.0% to 50.0% (v/v). The experimental results are approximately consistent with theory.

Huang, Jing; Li, Xueming; Yang, Jianchun

2013-12-01

309

Fiber-optic communication systems  

CERN Document Server

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

Agrawal, Govind P

2010-01-01

310

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)

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.

Dhadwal, Harbans Singh

1994-01-01

311

Supercontinuum fiber laser source for reflectance calibrations in remote sensing  

Science.gov (United States)

The Optical Technology Division of the National Institute of Standards and Technology (NIST) provides reference measurements of specular and diffuse reflectance of materials, including measurements that provide traceability for diffuser plaques that are used as onboard calibration standards in remote sensing. We are developing new instrumentation that will enable angle-resolved Bidirectional Reflectance Distribution Function (BRDF) measurements using a supercontinuum fiber laser-based source and a tunable monochromator. A significant improvement in optical power density at the specimen over that of lamp-based sources is expected. We present an overview of the source design and evaluation, including the predicted impact of supercontinuum sources on our next generation of BRDF measurement instrumentation.

Zarobila, Clarence J.; Patrick, Heather J.

2010-08-01

312

An in-fiber integrated optofluidic device based on an optical fiber with an inner core.  

Science.gov (United States)

A new kind of optofluidic in-fiber integrated device based on a specially designed hollow optical fiber with an inner core is designed. The inlets and outlets are built by etching the surface of the optical fiber without damaging the inner core. A reaction region between the end of the fiber and a solid point obtained after melting is constructed. By injecting samples into the fiber, the liquids can form steady microflows and react in the region. Simultaneously, the emission from the chemiluminescence reaction can be detected from the remote end of the optical fiber through evanescent field coupling. The concentration of ascorbic acid (AA or vitamin C, Vc) is determined by the emission intensity of the reaction of Vc, H2O2, luminol, and K3Fe(CN)6 in the optical fiber. A linear sensing range of 0.1-3.0 mmol L(-1) for Vc is obtained. The emission intensity can be determined within 2 s at a total flow rate of 150 ?L min(-1). Significantly, this work presents information for the in-fiber integrated optofluidic devices without spatial optical coupling. PMID:24799034

Yang, Xinghua; Yuan, Tingting; Teng, Pingping; Kong, Depeng; Liu, Chunlan; Li, Entao; Zhao, Enming; Tong, Chengguo; Yuan, Libo

2014-06-21

313

Skew radiation in optical fiber: the proposal of share measure  

Science.gov (United States)

The propagation of light in optical fiber one can describe with following methods: phase, propagation of bundle and optics of rays. At present, the foundation in model of ray optic take that ray is the flat wave with small field of intersection. This is well known, according to talked over model, that in optical fibers the following rays propagate: ballistic, meridional and skew. The presented work shows from mathematical side the description of ray propagation in optical fibers and the proposal of statistical measure of skew and meridional radiance share. For the visualization of this the close field distribution is useful. Turns out, that for large shares of skew rays close field distribution is homogeneous and its shape alters in sense of normal distribution from growing shares of meridional radiance.

Borecki, M.; Kruszewski, J.

2005-09-01

314

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Henault, Jm; Salin, J.; Moreau, G.; Delepine Lesoille, S.; Bertrand, J.; Taillade, Fre?de?ric; Quiertant, Marc; Benzarti, Karim

2010-01-01

315

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2011-01-01

316

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

David Sánchez Montero; Pedro Contreras Lallana; Carmen Vázquez

2012-01-01

317

Temperature and refractive index sensing characteristics of an MZI-based multimode fiber-dispersion compensation fiber-multimode fiber structure  

Science.gov (United States)

We proposed an optical fiber sensor with simple multimode fiber (MMF)-dispersion compensation fiber (DCF)-multimode fiber structure based on Mach-Zehnder Interferometer (MZI) and researched its temperature and refractive index (RI) sensing characteristics. The sensing principle is based on the interference between core and cladding modes of DCF due to the large core diameter mismatch. Spectral analyses demonstrate that the transmission spectrum is mainly formed by the interference between the dominant excited cladding mode and core modes. The experimental results show that the proposed sensor has high temperature sensitivity of 0.118 nm/°C in the range of 20-250 °C and RI sensitivity of 66.32 nm/RIU within the linear sensing range of 1.33-1.39 RIU. Therefore, the characteristics of compact size, low cost, easy fabrication, high sensitivities, and good anti-interference ability make this sensor have extensive application prospects.

Sun, Hao; Yang, Shen; Zhang, Jing; Rong, Qiangzhou; Liang, Lei; Xu, Qinfang; Xiang, Guanghua; Feng, Dingyi; Du, Yanying; Feng, Zhongyao; Qiao, Xueguang; Hu, Manli

2012-12-01

318

Remotely readable fiber optic compass  

Energy Technology Data Exchange (ETDEWEB)

A remotely readable fiber optic compass. A sheet polarizer is affixed to a magnet rotatably mounted in a compass body, such that the polarizer rotates with the magnet. The optical axis of the sheet polarizer is preferably aligned with the north-south axis of the magnet. A single excitation light beam is divided into four identical beams, two of which are passed through the sheet polarizer and through two fixed polarizing sheets which have their optical axes at right angles to one another. The angle of the compass magnet with respect to a fixed axis of the compass body can be determined by measuring the ratio of the intensities of the two light beams. The remaining ambiguity as to which of the four possible quadrants the magnet is pointing to is resolved by the second pair of light beams, which are passed through the sheet polarizer at positions which are transected by two semicircular opaque strips formed on the sheet polarizer. The incoming excitation beam and the four return beams are communicated by means of optical fibers, giving a remotely readable compass which has no electrical parts.

Migliori, Albert (Santa Fe, NM); Swift, Gregory W. (Los Alamos, NM); Garrett, Steven L. (Pebble Beach, CA)

1986-01-01

319

Engineering modes in optical fibers with metamaterial  

DEFF Research Database (Denmark)

In this paper, we report a preliminary theoretical study on optical fibers with fine material inclusions whose geometrical inhomogeneity is almost indistinguishable by the operating wavelength.We refer to such fibers as metamaterial optical fibers, which can conceptually be considered as an extension from the previously much publicized microstructured optical fibers. Metamaterials can have optical properties not obtainable in naturally existing materials, including artificial anisotropy as well as graded material properties. Therefore, incorporation of metamaterial in optical fiber designs can produce a new range of fiber properties. With a particular example, we will show how mode discrimination can be achieved in a multimode Bragg fiber with the help of metamaterial. We also look into the mean field theory as well as Maxwell-Garnett theory for homogenizing a fine metamaterial structure to a homogeneous one. The accuracies of the two homogenization approaches are compared with fullstructure calculation.

Yan, Min; Mortensen, Asger

2009-01-01

320

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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. ...

Xuefeng Zhao; Peng Gong; Guofu Qiao; Jie Lu; Xingjun Lv; Jinping Ou

2011-01-01

 
 
 
 
321

Monitoring the Evaporation of Fluids from Fiber-Optic Micro-Cell Cavities  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Eyal Preter; Borut Preloznik; Vlada Artel; Sukenik, Chaim N.; Denis Donlagic; Avi Zadok

2013-01-01

322

Optical Fiber LSPR Biosensor Prepared by Gold Nanoparticle Assembly on Polyelectrolyte Multilayer  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This article provides a novel method of constructing an optical fiber localized surface plasmon resonance (LSPR) biosensor. A gold nanoparticle (NP) assembled film as the sensing layer was built on the polyelectrolyte (PE) multilayer modified sidewall of an unclad optical fiber. By using a trilayer PE structure, we obtained a monodisperse gold NP assembled film. The preparation procedure for this LSPR sensor is simple and time saving. The optical fiber LSPR sensor has higher sensitivity and o...

Yunliang Shao; Shuping Xu; Xianliang Zheng; Ye Wang; Weiqing Xu

2010-01-01

323

Method and apparatus for distributed sensing of volatiles using a long period fiber grating sensor with modulated plastic coating for environmental monitoring  

Science.gov (United States)

Optical time domain reflectometry caused by absorption of a volatile or analyte into the fiber optic cladding is used as an optical nose. The fiber optics (14) are covered with a gas permeable film (44) which is patterned to leave millimeter wide gas permeable notches (48a-48d). The notches contain a sensing polymer that responds to different gases by expanding or contracting.

Ponce, Adrian (Inventor); Kossakovski, Dmitri A. (Inventor); Bearman, Gregory H. (Inventor)

2010-01-01

324

Fiber Optics Physics and Technology  

CERN Document Server

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...

Mitschke, Fedor

2010-01-01

325

Intensity-based optical fiber sensors for condition monitoring of engineering materials  

Science.gov (United States)

This paper presents a general overview of intensity-based optical fiber sensor systems, including those developed at Brunel University for condition and health monitoring of engineering materials. The sensor systems covered are: crack detection, a novel technique for converting glass reinforcing fibers into light guides for sensing applications, vibration monitoring and a new intensity- independent demodulation technique for fiber Fabry-Perot interferometers.

Doyle, Crispin T.; Martin, Anthony R.; Wu, M.; Liu, Tongyu; Hayes, Simon A.; Brooks, David; Badcock, Rodney A.; Fernando, Gerard F.

1996-09-01

326

Study on optical fiber based displacement sensor  

Science.gov (United States)

Fiber optic sensor is commonly used in control and monitoring system for material deformation, strain, temperature, pressure and other industrial process parameters. Fiber optic displacement sensor based on intensity modulation can be designed by using the transmission technique where the intensity gradually changes due to change of detected laser intensity. Previous optical fiber based displacement sensors are constructed using two fibers along with a mirror arrangement or a single optical fiber acting as both transmitter and receiver such as 2X1 fiber couplers. The reported resolution of the system was in the range of 5 ?m-10 ?m. In our present study the displacement sensor composed of a laser source, optical fiber cable, microscope objective and power meter is designed. As in source-fiber coupling geometry, the microscope objective focuses the laser light onto a multimode glass fiber. The other end of the fiber is coupled to a power meter. As the fiber is displaced towards the focused spot, the detected power changes. The displacement resolution of 5 ?m is obtained with this simple setup. In the present paper, the results of theoretical analysis and experimental study of such a simple optical fiber based displacement sensor are presented.

Chakraborty, B.; Sinha, B. K.

2011-10-01

327

Simulation of Three Different Double-Fiber Probes for Reflection Sensing  

Directory of Open Access Journals (Sweden)

Full Text Available In this study simulation results for three double-fiber optical designs for the reflection measurements are reported. Modeling is perused for three cases namely Equal Fibers (EF, transmitter fiber shorter (TS and receiver fiber shorter (RS designs. By proper modeling and written programs the operations of such symmetric double-fiber probes are simulated and the role of different crucial parameters such as fiber-to-fiber distance (t, fiber core radius (r and fiber Numerical Aperture (NA are investigated. In the second study simulation results for the transmitter fiber shorter and receiver fiber shorter designs are investigated for different fiber length differences (w. Finally simulation results for the three different designs of equal fibers, transmitter shorter and receiver fiber shorter probes are compared and optimum conditions are described. All three arrangements simulated here offer valuable results for sensing operations such as reflection or displacement measurements. However, the RS probe geometry offers a better design with the less dead region in comparison with the EF and TS designs.

R. Jafari

2010-01-01

328

Fiber optic neutron imaging system: calibration  

Energy Technology Data Exchange (ETDEWEB)

Two neutron imaging experiments using fiber optics have been performed at the Nevada Test Site. In each experiment, an array of scintillator fluor tubes is exposed to neutrons. Light is coupled out through radiation resistant PCS fibers (8-m long) into high-bandwidth, graded index fibers. For image reconstruction to be accurate, common timing differences and transmission variations between fiber optic channels are needed. The calibration system featured a scanning pulsed dye laser, a specially designed fiber optic star coupler, a Tektronix 7912AD transient digitizer, and a DEC PDP 11/34 computing system.

Malone, R.M.; Gow, C.E.; Thayer, D.R.

1981-01-01

329

Single-crystal fiber optics: a review  

Science.gov (United States)

Single-crystal (SC) fiber optics have been grown for many years for use as passive fibers for the delivery of IR laser radiation and as active fibers useful as minirod lasers. Most of the early work on SC fiber optics involved the growth of unclad sapphire fibers for the transmission of Er:YAG laser radiation at 2.94 ?m. More recently there has been a renewed interest in rare-earth (RE) doped oxide crystal fibers for use as high power fiber lasers. By analogy with RE doped-bulk laser crystals it is expected that pure YAG and other crystalline SC fibers should be capable of transmitting extremely high laser energies. SC oxide fibers have some distinct advantages over conventional glass fibers including higher thermal conductivity and low stimulated Brillouin scattering (SBS) gain coefficients. The latter can limit the ultimate power output of glass fiber lasers. To date most of the investigators have used the technique of Laser Heated Pedestal Growth (LHPG) to grow unclad SC fibers with diameters ranging from 30 to 350 ?m and in lengths as long as 5 m. The loss for SC sapphire fibers at 2.94 ?m has been measured as low as 0.3 dB/m. In this review we discuss the technique of LHPG, the various SC fiber optics that have been grown for both active and passive applications, and methods that may be used to clad the fibers.

Harrington, James A.

2014-02-01

330

The Soliton Transmissions in Optical Fibers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The objective of this paper is to familiarize readers with the basic analytical propagation model of short optical pulses in optical fiber. Based on this model simulation of propagation of the special type of pulse, called a soliton, will be carried out. A soliton transmission is especially attractive in the fiber optic telecommunication systems as it does not change a pulses shape during propagating right-down the fiber link to the receiver. The model of very short pulse propagation is based...

2010-01-01

331

Thermal Strain Analysis of Optic Fiber Sensors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Shiuh-Chuan Her; Chih-Ying Huang

2013-01-01

332

Photoactive coating for hardening optical fibers  

Energy Technology Data Exchange (ETDEWEB)

In accordance with the foregoing principles and objects of the present invention, an improved optical fiber structure is provided which is hardened against the effects of ionizing nuclear radiation and comprises a conventional plastic, glass or silica optical fiber core and cladding, having an additional outer coating comprising phosphorescent or luminescent material for interacting with the ionizing radiation to provide a source of light to optically bleach the fiber core of optical absorption sites produced as a result of the interaction of the ionizing radiation with the fiber core material.

Caldwell, R.S.

1982-07-29

333

Measuring soil strains using fiber optic sensors  

Science.gov (United States)

The measurement of strain within a compacted soil mass using optical fibers was demonstrated. The sensitivity of the fiber optic sensor was shown to match that of an existing soil strain sensor. Experimental data were gathered by dynamically loading the soil. Data from the optical fibers was processed by a Fabry-Perot interferometer into a localized strain. The data was verified by comparing with data obtained from a LVDT and a commercial soil strain sensor as well as theoretical data obtained from a finite element analysis. The data indicate that fiber optic sensors have the ability to detect viscoelastic soil strains and may be used to measure the permanent deformation of soil.

Miller, Craig E.; Sharma, M. G.; Sherwood, James A.

1996-04-01

334

Fiber optic MCM for spaceborne applications  

Science.gov (United States)

This paper presents a fiber optic packaging technique using qualifiable materials and processes that has been developed for space applications. The technique is consistent with a Multi Chip Module implementation. This packaging technique allows multiple fiber optic interfaces to be combined with high density electronics within a single easily integrable package and can be used wherever fiber optics are incorporated into spaceborne systems, including the Fiber Optic Data Bus, the Space Station FDDI interface, any upgrades of the Space Station Local Bus from 1553 to 1773, and various Dual Rate 1773 applications.

Bristow, Julian P.; Lehman, John A.; Liu, Yue; Goldberg, W. T.; Deruiter, John L.; Kersch, Dennis

1994-06-01

335

A Large Area Fiber Optic Gyroscope on multiplexed fiber network  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 km2 and coexists with Internet data traffic. This Sagnac interferometer achieves a sensitivity of about (10-8 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 kind of optical fi...

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

2013-01-01

336

Quantitative broadband chemical sensing in air-suspended solid-core fibers  

CERN Document Server

We demonstrate a quantitative broadband fiber sensor, based on evanescent field sensing in the cladding holes of an air-suspended solid-core photonic crystal fiber. We discuss the fabrication process, together with the structural- and optical characterization of a range of different fibers. Measured mode profiles are in good agreement with finite element method calculations made without free parameters. The fraction of the light in the hollow cladding can be tuned via the core diameter of the fiber. Dispersion measurements are in excellent agreement with theory and demonstrate tuning of the zero dispersion wavelength via the core diameter. Optimum design parameters for absorption sensors are discussed using a general parameter diagram. From our analysis, we estimate that a sensitivity increase of three orders of magnitude is feasible compared to standard cuvette measurements. Our study applies to both liquid and gas fiber sensors. We demonstrate the applicability of our results to liquid chemical sensing by m...

Euser, T G; Farrer, N J; Scharrer, M; Sadler, P J; Russell, P St J

2007-01-01

337

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Alexopoulos N.; Poulin P.; Bartholome C.; Marioli-Riga Z.

2010-01-01

338

Tunable Laser Development for In-flight Fiber Optic Based Structural Health Monitoring Systems  

Science.gov (United States)

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.

Richards, Lance; Parker, Allen; Chan, Patrick

2014-01-01

339

Fiber optic hydrogen detection system  

Science.gov (United States)

Commercial and military launch vehicles are designed to use hydrogen as the main propellant, which is very volatile, extremely flammable, and highly explosive. Current detection systems uses Teflon transfer tubes at a large number of vehicle locations through which gas samples are drawn and the stream analyzed by a mass spectrometer. A concern with this approach is the high cost of the system. Also, the current system does not provide leak location and is not in real-time. This system is very complex and cumbersome for production and ground support measurement personnel. The fiber optic micromirror sensor under development for cryogenic environment relies on a reversible chemical interaction causing a change in reflectivity of a thin film of coated Palladium. The magnitude of the reflectivity change is correlated to hydrogen concentration. The sensor uses only a tiny light beam, with no electricity whatsoever at the sensor, leading to devices that is intrinsically safe from explosive ignition. The sensor, extremely small in size and weight detects, hydrogen concentration using a passive element consisting of chemically reactive microcoatings deposited on the surface of a glass microlens, which is then bonded to an optical fiber. The system uses a multiplexing technique with a fiber optic driver-receiver consisting of a modulated LED source that is launched into the sensor, and a photodiode detector that synchronously measures the reflected signal. The system incorporates a microprocessor (or PC) to perform the data analysis and storage, as well as trending and set alarm function. As it is a low cost system with a fast response, many more detection sensors can be used that will be extremely helpful in determining leak location for safety of crew and vehicles during launch operations.

Kazemi, Alex A.; Larson, David B.; Wuestling, Mark D.

1999-12-01

340

Hollow-core photonic crystal fiber probe for remote fluorescence sensing with single molecule sensitivity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Current optical fiber probes for fluorescence spectroscopy struggle with large luminescence background and low detection sensitivities that challenge the detection of fluorescent molecules at sub-micromolar concentration. Here we report the demonstration of a hollow-core photonic crystal fiber (HC-PCF) probe for remote fluorescence sensing with single molecule sensitivity down to nanomolar concentrations, where both the excitation and fluorescence beams are counter-propagating through the sam...

Ghenuche, Petru; Rigneault, Herve; Wenger, Jerome

2012-01-01

 
 
 
 
341

Development of smart textiles with embedded fiber optic chemical sensors  

Science.gov (United States)

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.

Khalil, Saif E.; Yuan, Jianming; El-Sherif, Mahmoud A.

342

Fiber-Optic Continuous Liquid Sensor for Cryogenic Propellant Gauging  

Science.gov (United States)

An innovative fiber-optic sensor has been developed for low-thrust-level settled mass gauging with measurement uncertainty propellant tank fill levels from 2 to 98 percent. The proposed sensor uses a single 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

Xu. Wei

2010-01-01

343

Fiber Optic High Voltage Probe  

Energy Technology Data Exchange (ETDEWEB)

We developed a fiber coupled sensor to measure High Voltage directly using only light as the probe. We use the Pockles effect in lithium niobate crystal which will induce a phase shift in a laser beam that varies according to applied voltage. This can then be transformed into a modulation of beam intensity by polarizers, interferometery, or waveguide coupling. No voltage dividers are necessary, nor is any physical connection. This is accompanied by taking advantage of the structure of the power system itself, using voltage planes and dielectric insulation already present as the capacitive voltage divider. We hypothesize a bandwidth from GHz to DC. Such a system could be used in any application that calls for isolated and unobtrusive voltage sensing.

Matthew J. Heino

1999-08-01

344

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

Science.gov (United States)

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.

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

1990-01-01

345

Method for optical and mechanically coupling optical fibers  

Energy Technology Data Exchange (ETDEWEB)

A method and apparatus for splicing optical fibers. A fluorescing solder glass frit having a melting point lower than the melting point of first and second optical fibers is prepared. The solder glass frit is then attached to the end of the first optical fiber and/or the end of the second optical fiber. The ends of the optical fibers are aligned and placed in close proximity to each other. The solder glass frit is then heated to a temperature which is lower than the melting temperature of the first and second optical fibers, but which is high enough to melt the solder glass frit. A force is applied to the first and second optical fibers pushing the ends of the fibers towards each other. As the solder glass flit becomes molten, the layer of molten solder glass is compressed into a thin layer between the first and second optical fibers. The thin compressed layer of molten solder glass is allowed to cool such that the first and second optical fibers are bonded to each other by the hardened layer of solder glass.

Toeppen, John S. (Livermore, CA)

1996-01-01

346

All-optical photoacoustic imaging system using fiber ultrasound probe and hollow optical fiber bundle.  

Science.gov (United States)

An all-optical 3D photoacoustic imaging probe that consists of an optical fiber probe for ultrasound detection and a bundle of hollow optical fibers for excitation of photoacoustic waves was developed. The fiber probe for ultrasound is based on a single-mode optical fiber with a thin polymer film attached to the output end surface that works as a Fabry Perot etalon. The input end of the hollow fiber bundle is aligned so that each fiber in the bundle is sequentially excited. A thin and flexible probe can be obtained because the probe system does not have a scanning mechanism at the distal end. PMID:24104094

Miida, Yusuke; Matsuura, Yuji

2013-09-23

347

Optical pulse generation using fiber lasers and integrated optics  

International Nuclear Information System (INIS)

We have demonstrated an optical pulse forming system using fiber and integrated optics, and have designed a multiple-output system for a proposed fusion laser facility. Our approach is an advancement over previous designs for fusion lasers, and an unusual application of fiber lasers and integrated optics

1995-06-26

348

Optical pulse generation using fiber lasers and integrated optics  

Energy Technology Data Exchange (ETDEWEB)

We have demonstrated an optical pulse forming system using fiber and integrated optics, and have designed a multiple-output system for a proposed fusion laser facility. Our approach is an advancement over previous designs for fusion lasers, and an unusual application of fiber lasers and integrated optics.

Wilcox, R.B.; Browning, D.F.; Burkhart, S.C.; VanWonterghem, B.W.

1995-03-27

349

Online fiber-optic spectrophotometry  

Energy Technology Data Exchange (ETDEWEB)

The Savannah River Plant operates two radio-chemical separations areas to recover uranium and plutonium from nuclear reactor fuel and target assemblies. Chemical processes in these areas are controlled based on laboratory analysis of samples extracted from the process. While analytical results from the laboratory are reliable, the process of pulling samples, transporting them to the laboratory, analyzing them, and then reporting results is time consuming and potentially exposes many workers to highly radioactive solutions. To improve the timeliness of chemical information and reduce personnel radiation exposure, the Savannah River Laboratory has developed an online fiber optic spectrophotometer which combines three new technologies, fiber optics, diode array spectrophotometers, and multivariate data analysis. The analyzer monitors the uranium and nitrate concentration of seven aqueous process streams in a uranium purification process. The analyzer remotely controls the sampling of each process stream and monitors the relative flow rate through each sampler. Spectrophotometric data from the analyzer is processed by multivariate data analysis to give both uranium and nitrate concentrations as well as an indication of the quality of the data.

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

1989-01-01

350

Seismic damage identification for steel structures using distributed fiber optics.  

Science.gov (United States)

A distributed fiber optic monitoring methodology based on optic time domain reflectometry technology is developed for seismic damage identification of steel structures. Epoxy with a strength closely associated to a specified structure damage state is used for bonding zigzagged configured optic fibers on the surfaces of the structure. Sensing the local deformation of the structure, the epoxy modulates the signal change within the optic fiber in response to the damage state of the structure. A monotonic loading test is conducted on a steel specimen installed with the proposed sensing system using selected epoxy that will crack at the designated strain level, which indicates the damage of the steel structure. Then, using the selected epoxy, a varying degree of cyclic loading amplitudes, which is associated with different damage states, is applied on a second specimen. The test results show that the specimen's damage can be identified by the optic sensors, and its maximum local deformation can be recorded by the sensing system; moreover, the damage evolution can also be identified. PMID:19649054

Hou, Shuang; Cai, C S; Ou, Jinping

2009-08-01

351

High Spatial Resolution Fiber-Optic Distributed Lateral-Stress Sensing by Stepwise Frequency Modulation of a Super Structure Grating Distributed Bragg Reflector Laser Diode  

Science.gov (United States)

We have reported recently a distributed lateral-stress sensor based on the polarization mode coupling in polarization-maintaining fiber (PMF), in which the frequency of a super structure grating distributed Bragg reflector laser diode (SSG-DBR-LD) source was modulated stepwise to synthesize the optical coherence function into a narrow peak for spatially resolved detection. Its spatial resolution, however, was limited to 2.5 m due to the instability of the lasing frequency (J. Lightw. Technol., vol. 20, p. 1715, 2002). In this paper, the effect of the frequency instability on the synthesized coherence function is studied per simulation. By improving the driving electronics and the frequency calibration of the SSG-DBR-LD, a stable stepwise frequency modulation over a range of 5 THz is obtained, which enables the synthesis of a coherence peak as narrow as 24 µm in the experiment. The spatial resolution of the distributed stress sensor is thus improved to 20 cm. This technique can be used for smart materials and structures.

Hotate, Kazuo; Makino, Koji; He, Zuyuan; Ishikawa, Mitsuteru; Yoshikuni, Yuzo

2006-07-01

352

Optical fiber sensor based on a radio frequency Mach-Zehnder interferometer.  

Science.gov (United States)

This Letter proposes an optical fiber radio frequency (RF) Mach-Zehnder interferometer (MZI) for sensing applications. An RF modulated laser source is injected into an optical fiber RF-MZI and collected by a photodiode. The interference pattern is observed in the RF domain by sweeping the frequency using a network analyzer. The proposed sensor has a linear response to applied temperature change. In addition, the sensitivity, observation frequency range, and the length of the sensing arm are discussed. PMID:22344135

Wei, Tao; Huang, Jie; Lan, Xinwei; Han, Qun; Xiao, Hai

2012-02-15

353

Long distance fiber-optic displacement sensor based on fiber collimator  

Science.gov (United States)

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.

Shen, Wei; Wu, Xiaowei; Meng, Hongyun; Zhang, Guanbin; Huang, Xuguang

2010-12-01

354

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

1978-01-01

355

Feasibility of giant fiber-optic gyroscopes  

CERN Document Server

The availability of long-distance, underground fiber-optic links opens a perspective of implementing interferometric fiber-optic gyroscopes embracing very large areas. We estimate the potential sensitivity of such configurations and discuss some disturbances and approaches to overcome them.

Schiller, Stephan

2013-01-01

356

Fiber optic intracranial pressure sensor system  

Science.gov (United States)

Fiber optics, thanks to its many advantages finds new areas of ap plication in medicine. This paper describes a fiber optic pressure sensor system. A short sensor theory, a building of a sensor probe and a callibration during measure methode are given.

Dorosz, Jan; Kruczkowski, Krzysztof

1990-07-01

357

Fiber optic sensors for gas turbine control  

Science.gov (United States)

An apparatus for detecting flashback occurrences in a premixed combustor system having at least one fuel nozzle includes at least one photodetector and at least one fiber optic element coupled between the at least one photodetector and a test region of the combustor system wherein a respective flame of the fuel nozzle is not present under normal operating conditions. A signal processor monitors a signal of the photodetector. The fiber optic element can include at least one optical fiber positioned within a protective tube. The fiber optic element can include two fiber optic elements coupled to the test region. The optical fiber and the protective tube can have lengths sufficient to situate the photodetector outside of an engine compartment. A plurality of fuel nozzles and a plurality of fiber optic elements can be used with the fiber optic elements being coupled to respective fuel nozzles and either to the photodetector or, wherein a plurality of photodetectors are used, to respective ones of the plurality of photodetectors. The signal processor can include a digital signal processor.

Shu, Emily Yixie (Inventor); Petrucco, Louis Jacob (Inventor); Daum, Wolfgang (Inventor)

2005-01-01

358

Optical Rotation-Sensing Interferometer with (3X3)-(2X2) Directional Coupler.  

Science.gov (United States)

This document describes a Sagnac rotation-sensing interferometer with a fiber-optic loop for providing a closed optical path in which counter-propagating light beams are phase shifted due to the Sagnac effect and with an optical coupler for splitting an i...

S. K. Sheem

1982-01-01

359

Seismic fiber optic multiplexed sensors for exploration and reservoir management  

Science.gov (United States)

Reliable downhole communications, control and sensor networks will dramatically improve oil reservoir management practices and will enable the construction of intelligent or smart-well completions. Fiber optic technology will play a key role in the implementation of these communication, control and sensing systems because of inherent advantages of power, weight and reliability over more conventional electronic-based systems. Field test data, acquired using an array of fiber optic seismic hydrophones within a steam-flood, heavy oil- production filed, showed a significant improvement (10X in this specific case) in subsurface resolution as compared to conventional surface seismic acquisition. These results demonstrate the viability of using multiplexed fiber optic sensors for exploration and reservoir management in 3D vertical seismic profiling (VSP) surveys and in permanent sensor arrays for 4D surveys.

Houston, Mark H.

2000-12-01

360

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

2007-04-04

 
 
 
 
361

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

Science.gov (United States)

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.

Montero, David Sanchez; Lallana, Pedro Contreras; Vazquez, Carmen

2012-01-01

362

Single-mode optical fiber cable.  

Science.gov (United States)

A single-mode optical fiber cable was manufactured; loss increase characteristics due to cabling were evaluated. The existence of wide V-value regions without cabling loss increases is shown by a suitable selection of fiber parameters and optical wavelengths. A selection method for fiber parameters, which minimizes cabling and splicing loss increases, is discussed. Selected values are Delta = 0.2% and V = 2.2, based on experimental results. PMID:20212639

Katsuyama, Y; Mochizuki, S; Ishihara, K; Miyashita, T

1979-07-01

363

Fiber-optic time domain reflectometer  

Energy Technology Data Exchange (ETDEWEB)

An optical time domain reflectometer is described which combines in one instrument the basic capability to analyze several important fiber characteristics. The device uses the polarization properties of light to enable high sensitivity fault detection close to the fiber input end; its probe pulse temporal characteristics and high gain photodetector in combination provide excellent discontinuity location resolution in long lossy fibers, and give an indication of fiber dispersion at large bandwidths.

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

1978-01-01

364

Optical amplification for the fiber interferometer gyro  

International Nuclear Information System (INIS)

An improvement for a fiber interferometer gyro provides for greater rotation rate sensitivity. The gyro has a single mode fiber coiled about an identical area a great number of times. A single external laser sends pulses of energy which are split and passed in opposite directions through the coiled fiber and a pair of optical amplifiers inserted to amplify the energy pulses. This permits the length of the coiled fiber to be increased and, hence , provides for greater interferometer sensitivity

1981-01-01

365

Linear and nonlinear properties in soft glass optical fibers for device applications  

Science.gov (United States)

Optical fiber technology is predominantly based on silica glass fibers. Non-silica soft glass fibers exhibit substantially different optical properties such as higher refractive index, larger nonlinear coefficient and structural fabrication flexibility. We aim to exploit these novel properties for device applications such as sensing and light generation. We report measurement of linear dispersion and nonlinear coefficient in the range of 1.5 ?m in two custom designed soft glass microstructure optical fibers. The fibers are composed of SF57 (Schott) and Bismuth-doped silica (Asahi Glass Co.) respectively with Hexagonal Wagonwheel microstructure design. These fibers are designed to allow phase matching of nonlinear optical processes near 1.6?m. Our measurements indicate nonlinear coefficients 1000 times that of standard silica fiber. Transverse modes in these fibers are difficult to separate leading to a complicated dispersion results. Next steps include observation of parametric generation and Brillouin gain.

Kiani, Leily; Munasinghe, Tilanka; Zhang, Wen Qi; Afshar, Shahraam; Sharping, Jay

2012-02-01

366

Optically driven deposition of nanostructures on optical fiber end faces  

Science.gov (United States)

We present a simple and inexpensive way to incorporate nanostructures in optical fibers based on optically driven transport of nanoparticles. The technique has been previously used to incorporate carbon nanotubes in fiber laser systems and relies on the deposition of nanostructures driven by the optical radiation propagating in the fiber. We demonstrate that this technique allows for incorporating graphite nanotubes and nanoparticles on the tip of the fibers and fiber connectors. Flow visualization techniques and thermal analysis of the deposition process show experimental evidence of the thermophoretic and pressure gradients involved in the incorporation of nanostructures onto optical fibers. Furthermore, we demonstrate the formation of micron sized bubbles on the tip of the fibers coated with nanostructures and show that this technique could render useful for developing micro bubble generators and mixers for micron sized structures.

Pimentel-Domínguez, Reinher; Cuando-Espitia, Natanael; Hernández-Cordero, Juan

2010-10-01

367

Development of fiber optic cabling technology  

Energy Technology Data Exchange (ETDEWEB)

Optical glass fiber is a better choice than copper media for supporting both today/tomorrow`s communication network requirements. The optical fiber cable as its final product will play an important role in the high bandwidth superhighway traffic that networks will soon carry. The basic manufacturing technology of fiber optic cables, including its processes and materials, entails the same as that of the conventional copper wire cable, but the performance of the final products is strongly dependent on the details of the cabling designs, materials and processes because the optical fiber is extremely sensitive to environmental conditions. This paper will discuss the technological development of optical fiber cables used in various communication applications.

Oh, P.S. [Optical Cable Corporation, Roanoke, VA (United States)

1995-12-01

368

Power system applications of fiber optics  

Energy Technology Data Exchange (ETDEWEB)

Power system applications of optical systems, primarily using fiber optics, are reviewed. The first section of the report reviews fibers as components of communications systems. The second section deals with fiber sensors for power systems, reviewing the many ways light sources and fibers can be combined to make measurements. Methods of measuring electric field gradient are discussed. Optical data processing is the subject of the third section, which begins by reviewing some widely different examples and concludes by outlining some potential applications in power systems: fault location in transformers, optical switching for light-fired thyristors and fault detection based on the inherent symmetry of most power apparatus. The fourth and final section is concerned with using optical fibers to transmit power to electronic equipment in a high-voltage situation, potentially replacing expensive high-voltage low-power transformers. JPL has designed small photodiodes specifically for this purpose, and fabricated and tested several samples.

Kirkham, H.; Johnston, A.; Lutes, G.; Daud, T.; Hyland, S.

1984-03-01

369

Power system applications of fiber optics  

Science.gov (United States)

Power system applications of optical systems, primarily using fiber optics, are reviewed. The first section reviews fibers as components of communication systems. The second section deals with fiber sensors for power systems, reviewing the many ways light sources and fibers can be combined to make measurements. Methods of measuring electric field gradient are discussed. Optical data processing is the subject of the third section, which begins by reviewing some widely different examples and concludes by outlining some potential applications in power systems: fault location in transformers, optical switching for light fired thyristors and fault detection based on the inherent symmetry of most power apparatus. The fourth and final section is concerned with using optical fibers to transmit power to electric equipment in a high voltage situation, potentially replacing expensive high voltage low power transformers. JPL has designed small photodiodes specifically for this purpose, and fabricated and tested several samples. This work is described.

Kirkham, H.; Johnston, A.; Lutes, G.; Daud, T.; Hyland, S.

1984-01-01

370

Fiber optic MEMS pressure sensors based on evanescent field interaction  

Science.gov (United States)

Micro-opto-electro-mechanical sensors (MOEMS) where optics are integrated with micro-electro-mechanical systems are logical candidates for sensing flow properties in high temperature and pressure applications. MOEMS offer high frequency response, small size, immunity to electromagnetic interference, and resistance to degradation from exposure to harsh environments. Interfacing MEMS sensors with fiber optics is quite challenging. We are investigating novel transduction and coupling methods based on evanescent field interaction and fiber bending methods. An evanescent field, created when total internal reflection between two dielectric media occurs, is an electromagnetic field in the lower index medium. In the case of fiber optics, the evanescent field decays exponentially away from the fiber core/cladding interface. The decay length depends on refractive indices and incident angles inside the fiber. Bringing a foreign object close to the exposed core introduces a change in the effective index and as a result, the transmitted light output is modified. Sensors can also be designed based on the `touching' and `bending' of the fiber optic. In this case, the output light is affected in a linear manner as opposed to the evanescent mode interaction where the sensitivity is exponential. Experimental results obtained regarding pressure sensors for both of these methods are discussed in terms of sensitivity, temperature effect, design parameters, and fabrication techniques.

Tabib-Azar, Massood; Sutapun, Boonsong; Glawe, Diana

1998-03-01

371

A Large Area Fiber Optic Gyroscope on multiplexed fiber network  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Clivati, Cecilia; Calonico, Davide; Costanzo, Giovanni A.; Mura, Alberto; Pizzocaro, Marco; Levi, Filippo

2012-01-01

372

Optical fiber sensor having an active core  

Science.gov (United States)

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.

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

1993-01-01

373

Modeling and testing of static pressure within an optical fiber cable spool using distributed fiber Bragg gratings  

Science.gov (United States)

Based on the force analysis, we establish a theoretical model to study the static pressure distribution of the fiber cable spool for the fiber optic guided missile (FOG-M). Simulations indicate that for each fiber layer in the fiber cable spool, the applied static pressure on it asymptotically converges as the number of fiber layers increases. Using the distributed fiber Bragg grating (FBG) sensing technique, the static pressure of fiber cable layers in the spool on the cable winding device was measured. Experiments show that the Bragg wavelength of FBG in every layer varies very quickly at the beginning and then becomes gently as the subsequent fiber cable was twisted onto the spool layer by layer. Theoretical simulations agree qualitatively with experimental results. This technology provides us a real-time method to monitor the pressure within the fiber cable layer during the cable winding process.

Ma, Chengju; Ren, Liyong; Qu, Enshi; Tang, Feng; Liang, Quan

2012-11-01

374

Low-cost fiber-optic chemochromic hydrogen detector  

Energy Technology Data Exchange (ETDEWEB)

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.

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

1998-08-01

375

Analysis of a distributed fiber-optic temperature sensor using single-photon detectors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We demonstrate a high-accuracy distributed fiber-optic temperature sensor using superconducting nanowire single-photon detectors and single-photon counting techniques. Our demonstration uses inexpensive single-mode fiber at standard telecommunications wavelengths as the sensing fiber, which enables extremely low-loss experiments and compatibility with existing fiber networks. We show that the uncertainty of the temperature measurement decreases with longer integration period...

Dyer, Shellee D.; Tanner, Michael G.; Baek, Burm; Hadfield, Robert H.; Nam, Sae Woo

2011-01-01

376

Analysis of a distributed fiber-optic temperature sensor using single-photon detectors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We demonstrate a high-accuracy distributed fiber-optic temperature sensor using superconducting nanowire single-photon detectors and single-photon counting techniques. Our demonstration uses inexpensive single-mode fiber at standard telecommunications wavelengths as the sensing fiber, which enables extremely low-loss experiments and compatibility with existing fiber networks. We show that the uncertainty of the temperature measurement decreases with longer integration periods, but is ultimate...

Dyer, S. D.; Tanner, M. G.; Baek, B.; Hadfield, R.; Nam, S. W.

2012-01-01

377

High capacity fiber optic sensor networks using hybrid multiplexing techniques and their applications  

Science.gov (United States)

Fiber optic sensor network is the development trend of fiber senor technologies and industries. In this paper, I will discuss recent research progress on high capacity fiber sensor networks with hybrid multiplexing techniques and their applications in the fields of security monitoring, environment monitoring, Smart eHome, etc. Firstly, I will present the architecture of hybrid multiplexing sensor passive optical network (HSPON), and the key technologies for integrated access and intelligent management of massive fiber sensor units. Two typical hybrid WDM/TDM fiber sensor networks for perimeter intrusion monitor and cultural relics security are introduced. Secondly, we propose the concept of "Microstructure?Optical X Domin Refecltor (M-OXDR)" for fiber sensor network expansion. By fabricating smart micro-structures with the ability of multidimensional encoded and low insertion loss along the fiber, the fiber sensor network of simple structure and huge capacity more than one thousand could be achieved. Assisted by the WDM/TDM and WDM/FDM decoding methods respectively, we built the verification systems for long-haul and real-time temperature sensing. Finally, I will show the high capacity and flexible fiber sensor network with IPv6 protocol based hybrid fiber/wireless access. By developing the fiber optic sensor with embedded IPv6 protocol conversion module and IPv6 router, huge amounts of fiber optic sensor nodes can be uniquely addressed. Meanwhile, various sensing information could be integrated and accessed to the Next Generation Internet.

Sun, Qizhen; Li, Xiaolei; Zhang, Manliang; Liu, Qi; Liu, Hai; Liu, Deming

2013-12-01

378

Poly aniline Nano fiber as Modified Cladding for Optical Fiber Sensor to Detect Acetone Vapor  

International Nuclear Information System (INIS)

In this research, we used poly aniline nano fiber as modified cladding material for a fiber optic sensor system to detect the acetone vapor. The sensor was designed based on variation of evanescent field absorption on the core-modified cladding interface when exposed with varied acetone vapor. Poly aniline nano fiber synthesized by interfacial polymerization was coated onto the un-cladded core and acts as sensing element. Response of the fiber optic sensor was investigated by measuring the transmission light intensity via fiber optic sensor system while exposed with acetone vapor. Based on the sensor response curve, it is obtained a very fast response time of 30 s and recovery time of 10 s. The fiber optic sensor also exhibits a good reversibility and repeatability. Sensitivity of the sensor to variation of acetone vapor pressure was obtained 1.25 %/mmHg, that means the transmission intensity of the sensor changes 1.25 % for acetone vapor change of 1 mmHg. (author)

2008-06-01

379

Fiber-optic chemical sensors for competitive binding fluoroimmunoassay  

Energy Technology Data Exchange (ETDEWEB)

This paper describes the development of a fiber-optic chemical sensor based on the principle of competitive-binding fluorescence immunoassay. Rabbit immunoglobin G (IgG) is covalently immobilized on the distal sensing tip of a quartz optical fiber. The sensor is exposed to fluorescein isothiocyanate (FITC) labeled and unlabeled anti-rabbit IgG. The 488-nm line of an argon-ion laser provides excitation of sensor-bound analyte. This results in fluorescence emission at the optical fiber's sensing tip. Sensor response is inversely proportional to the amount of unlabeled anti-IgG in the sample. Limits of detection (LOD) vary with incubation time, sample size, and measurement conditions. For 10-/sup +/L samples, typical LOD are 25 fmol of unlabeled antibody in a 20-min incubation period. These results indicate that each fiber-optic fluoroimmunosensor can be constructed to perform a single sensitive, rapid, low-volume immunoassay, in in situ or benchtop applications.

Tromberg, B.J.; Sepaniak, M.J.; Vo-Dinh, T.; Griffin, G.D.

1987-04-15

380

Fiber optic D dimer biosensor  

Energy Technology Data Exchange (ETDEWEB)

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.

Glass, Robert S. (Livermore, CA); Grant, Sheila A. (Pleasanton, CA)

1999-01-01

 
 
 
 
381

Curved Piezoelectric Actuators for Stretching Optical Fibers  

Science.gov (United States)

Assemblies containing curved piezoceramic fiber composite actuators have been invented as means of stretching optical fibers by amounts that depend on applied drive voltages. Piezoceramic fiber composite actuators are conventionally manufactured as sheets or ribbons that are flat and flexible, but can be made curved to obtain load-carrying ability and displacement greater than those obtainable from the flat versions. In the primary embodiment of this invention, piezoceramic fibers are oriented parallel to the direction of longitudinal displacement of the actuators so that application of drive voltage causes the actuator to flatten, producing maximum motion. Actuator motion can be transmitted to the optical fiber by use of hinges and clamp blocks. In the original application of this invention, the optical fiber contains a Bragg grating and the purpose of the controlled stretching of the fiber is to tune the grating as part of a small, lightweight, mode-hop-free, rapidly tunable laser for demodulating strain in Bragg-grating strain-measurement optical fibers attached to structures. The invention could also be used to apply controllable tensile force or displacement to an object other than an optical fiber.

Allison, Sidney G.; Shams, Qamar A.; Fox, Robert L.

2008-01-01

382

Internal and External Optical Feedback Effect in Fiber Linear Lasers  

Directory of Open Access Journals (Sweden)

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

Junping Zhou

2013-09-01

383

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

Energy Technology Data Exchange (ETDEWEB)

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.

Wilcox, Russell B.; Byrd, J.M.; Doolittle, Lawrence; Huang, Gang; Staples, J.W.

2009-07-29

384

Transmission of ?erenkov radiation in optical fibers  

Science.gov (United States)

?erenkov radiation is generated as an unwanted background when optical fibers carrying signals passthrough radiation fields. The angular dependence of the intensity of ?erenkov radiation transmitted in silica-core fibers was measured using 6 and 12 MeV electron beams from a Varian Clinac accelerator. These confirmed theoretical predictions that the angular variation of ?erenkov radiation transmitted along optical fibers depends only on the refractive index difference ?n between the core and the cladding, and that the peak intensity is proportional to the cube of the fiber core radius.

Law, S. H.; Suchowerska, N.; McKenzie, D. R.; Fleming, S. C.; Lin, T.

2007-05-01

385

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

Directory of Open Access Journals (Sweden)

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.

Manuel Lopez-Amo

2013-06-01

386

Thermal strain analysis of optic fiber sensors.  

Science.gov (United States)

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. PMID:23385407

Her, Shiuh-Chuan; Huang, Chih-Ying

2013-01-01

387

Refractive index sensing characterization of a singlemode-claddingless-singlemode fiber structure based fiber ring cavity laser.  

Science.gov (United States)

This paper firstly demonstrated the refractive index (RI) characteristics of a singlemode-claddingless-singlemode fiber structure filter based fiber ring cavity laser sensing system. The experiment shows that the lasing wavelength shifts to red side with the ambient RI increase. Linear and parabolic fitting are both done to the measurements. The linear fitting result shows a good linearity for applications in some areas with the determination coefficient of 0.993. And a sensitivity of ~131.64nm/RIU is experimentally achieved with the aqueous solution RI ranging from 1.333 to 1.3707, which is competitively compared to other existing fiber-optic sensors. While the 2 order polynomial fitting function, which determination relationship is higher than 0.999, can be used to some more rigorous monitoring. The proposed fiber laser has a SNR of ~50dB, and 3dB bandwidth ~0.03nm. PMID:24663842

Liu, Zhi-bo; Tan, Zhongwei; Yin, Bin; Bai, Yunlong; Jian, Shuisheng

2014-03-10

388

High-sensitivity bend angle measurements using optical fiber gratings.  

Science.gov (United States)

We present a high-sensitivity and more flexible bend measurement method, which is based on the coupling of core mode to the cladding modes at the bending region in concatenation with optical fiber grating serving as band reflector. The characteristics of a bend sensing arm composed of bending region and optical fiber grating is examined for different configurations including single fiber Bragg grating (FBG), chirped FBG (CFBG), and double FBGs. The bend loss curves for coated, stripped, and etched sections of fiber in the bending region with FBG, CFBG, and double FBG are obtained experimentally. The effect of separation between bending region and optical fiber grating on loss is measured. The loss responses for single FBG and CFBG configurations are compared to discover the effectiveness for practical applications. It is demonstrated that the sensitivity of the double FBG scheme is twice that of the single FBG and CFBG configurations, and hence acts as sensitivity multiplier. The bend loss response for different fiber diameters obtained through etching in 40% hydrofluoric acid, is measured in double FBG scheme that resulted in a significant increase in the sensitivity, and reduction of dead-zone. PMID:23872750

Rauf, Abdul; Zhao, Jianlin; Jiang, Biqiang

2013-07-20

389

Optical fiber cable chemical stripping fixture  

Science.gov (United States)

An elongated fixture handle member is connected to a fixture body member with both members having interconnecting longitudinal central axial bores for the passage of an optical cable therethrough. The axial bore of the fixture body member, however, terminates in a shoulder stop for the outer end of a jacket of the optical cable covering both an optical fiber and a coating therefor, with an axial bore of reduced diameter continuing from the shoulder stop forward for a predetermined desired length to the outer end of the fixture body member. A subsequent insertion of the fixture body member including the above optical fiber elements into a chemical stripping solution results in a softening of the exposed external coating thereat which permits easy removal thereof from the optical fiber while leaving a desired length coated fiber intact within the fixture body member.

Kolasinski, John R. (Inventor); Coleman, Alexander M. (Inventor)

1995-01-01

390

Multiwavelength monolithic integrated fiber-optic terminal  

Science.gov (United States)

The paper presents the Multiwavelength Monolithic Integrated Fiber Optic Terminal (MMIFOT) developed under NASA sponsorship. The program aims to utilize the advantage of optical fiber and integrated optical device technology to achieve parallel transmission of many data channels over the same optical fiber link, and to develop an eight channel wavelength multiplexed fiber optic link that transmits eight bit words in a parallel format at a nominal rate of 20 Mw/s; in the second phase of the program a transmitter/multiplexer chip will be developed. The MMIFOT configuration, the receiver/demultiplexer development, and the waveguide detector development are discussed, concluding that the first phase of the MMIFOT program will culminate in the demonstration of an eight channel receiver/demultiplexer chip with a four channel breadboard multiplexer with the data rate of 20 Mbps per channel with a dynamic range of minimum 20 dB.

Rice, R. R.; Zino, J. D.; Bryan, D. A.; Dalke, E. A.; Reed, W. R.

1979-01-01

391

Development of distributed fiber optic sensor system for electric power systems (III)  

Energy Technology Data Exchange (ETDEWEB)

In this research, the key technologies on the distributed fiber optic sensor system are developed. A high power pulse laser driver is designed. The optical coupler for discriminating backscattered optical signal and splicing sensing optical fiber, and signal precessing electronics for receiving backscattered optical signal are also developed. By using the parallel processing algorithms and EPLD technique, a high speed signal averaged which is used for improving the signal to noise ratio is developed. A communication software used for sending received optical sensing signal to personal computer and a graphic software used for displaying the measurement result on personal computer monitor are developed. Test of distributed fiber optic sensor system was made along 1.1 km optical fiber. Experimental results show that optical output power of the backscattering light wave exponentially decays as the time axis approaches to the fiber end point. Since the output power of backscattered signal is very weak, the high speed signal averaged which is used for improving the signal to noise ratio and parallel processing algorithm which is used for reducing the measuring time of distributed fiber optic sensor system should be adapted. In the near future, developed technologies will be applied to new application system about distributed fiber optic sensor system. (author). refs., figs., tabs.

Kim, Y. S.; Kim, Y. H.; Oh, S. K.; Kim, I. S.; Park, H. S.; Roh, J. D. [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of)

1996-12-01

392

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

Directory of Open Access Journals (Sweden)

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.

Marioli-Riga Z.

2010-06-01

393

Specialty optical fiber products for sensor applications  

Science.gov (United States)

3M has developed and commercialized a line of specialty single-mode fibers to meet the unique requirements of advanced fiber optic sensor applications. 3M implements a dual- technology approach which combines novel materials technology with optical waveguide design to produce high-performance fibers which have been qualified in many military and aerospace programs. The 3M product offering includes high numerical aperture single-mode fibers which tightly confine the guided mode to resist bending losses in miniature sensor packaging configurations. 3M offers a complete line of polarization-control fiber products to allow all-fiber construction of sensor optical circuits. Standard polarization-maintaining fibers that feature reduced size and high numerical aperture are designed specifically for use in high- density, miniature sensor coil applications. 3M single-polarization (polarizing) fiber is remarkably versatile, enabling system construction and packaging previously limited by conventional polarizer technology. All 3M polarization-control products employ unique coating and packaging materials to meet demanding optical and mechanical specifications from -55 degree(s)C to +85 degree(s)C. Fiber specifications and performance data, including radiation performance, will be presented along with strength and reliability data.

Sanders, Paul E.

1994-11-01

394

Microcontroller Based Mobile Platform with Fiber Optic Sensors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the present work a mobile platform with optical fiber sensor was designed, built and tested. The IC 89C51RD2 was used as controller on the platform. The platform was designed with two powered wheels on the back and one free turning wheel on the front. Further the platform was outfitted with proximity, weight and touch plastic fiber sensors. Home position was sensed by touch sensor, the destination by proximity sensor and weight by the load cell sensor. A program was written to move the pla...

2013-01-01

395

Fiber optic gas sensor with nanocrystalline ZnO  

Science.gov (United States)

A fiber optic gas sensor with a PMMA fiber whose clad is modified with chemically sensitive nano-crystalline zinc oxide has been developed and investigated to detect acetone, isopropyl alcohol and benzene gases. The spectral characteristics of the sensor were recorded for different concentrations ranging from (0-500 ppm) for these gases both with as-prepared and annealed nanocrystalline ZnO, and the influence of annealing on the gas sensing has been studied.The response time and recovery time were found to be 48 min. and 42 min. respectively for 500 ppm concentration.

Renganathan, B.; Ganesan, A. R.

2014-01-01

396

NO2 detection with a fiber optic evanescent wave sensor  

Science.gov (United States)

A novel approach for the detection of nitrogen dioxide gas is described. This optical fiber based sensor (FOS) works on the principal of evanescent wave (EW) absorption phenomenon. EWs at the uncladded portion of a multimode fiber is utilized for the senor development by replacing this region with a coating of Metallophthalocyanine, which is thermally deposited at a reduced pressure. MPcs are very sensitive to NO2 gas and there is a change in the EW absorption in the NO2 environment. Compared to other gas sensing devices, this is highly sensitive technique. The attraction of this FOS is its simple architecture and the easiness to implement.

Mechery, John S.; Thomas, Jayan; Unnikrishnan, K. P.; Radhakrishnan, P.; Nampoori, V. P.; Vallabhan, C. P.

1999-11-01

397

Distributed Optical Fiber Vibration Sensor Based on Rayleigh Backscattering  

Science.gov (United States)

This thesis includes studies of developing distributed optical fiber vibration sensor based on Rayleigh backscattering with broad frequency response range and high spatial resolution. Distributed vibration sensor based on all-polarization-maintaining configurations of the phase-sensitive optical time domain reflectometry (OTDR) is developed to achieve high frequency response and spatial resolution. Signal fading and noise induced by polarization change can be mitigated via polarization-maintaining components. Pencil-break event is tested as a vibration source and the layout of the sensing fiber part is designed for real applications. The spatial resolution is 1m and the maximum distance between sensing fiber and vibration event is 18cm. Wavelet denoising method is introduced to improve the performance of the distributed vibration sensor based on phase-sensitive OTDR in standard single-mode fiber. Noise can be reduced more effectively by thresholding the wavelet coefficient. Sub-meter spatial resolution is obtained with a detectable frequency up to 8 kHz. A new distributed vibration sensor based on time-division multiplexing (TDM) scheme is also studied. A special probe waveform including a narrow pules and a quasi-continuous wave can combine the conventional phase-sensitive OTDR system and polarization diversity scheme together in one single-mode fiber without crosstalk. Position and frequency of the vibration can be determined by these two detection systems consecutively in different time slots. Vibration event up to 0.6 MHz is detected with 1m spatial resolution along a 680m single-mode sensing fiber. Continuous wavelet transform (CWT) is investigated to study the non-stationary vibration events measured by our phase OTDR system. The CWT approach can access both frequency and time information of the vibration event simultaneously. Distributed vibration measurements of 500Hz and 500Hz to 1 kHz sweep events over 20 cm fiber length are demonstrated using a single-mode fiber. Optical frequency-domain reflectometry (OFDR) for vibration sensing is proposed for the first time. The local Rayleigh backscatter spectrum shift in time sequence could be used to determine dynamic strain information at a specific position of the vibrated state with respect to that of the non-vibrated state. Measurable frequency range of 0-32 Hz with the spatial resolution of 10 cm is demonstrated along a 17 m fiber.

Qin, Zengguang

398

Fiber Optic Connector Polishing Fixture Assembly  

Science.gov (United States)

A fiber optic connector polishing fixture assembly for sup- porting a terminus of a fiber optic cable before a polishing surface. The assembly comprises: a fiber optic polishing fixture adapted to support the terminus before the polishing surface; a fixture support connected to the fixture for sup- porting the fixture before the polishing surface; and an adjustable connection between the fixture and the fixture support having user accessible adjustment controls for allowing a user to operate the controls to shift the fixture and fixture support relative to one another for substantially eliminating an apex offset of the terminus with respect to the polishing surface.

Kolasinski, John R. (Inventor); Moszcziewski, Joseph Roch (Inventor)

2003-01-01

399

Fiber optic communication in borehole applications  

Energy Technology Data Exchange (ETDEWEB)

The Telemetry Technology Development Department have, in support of the Advanced Geophysical Technology Department and the Oil Recovery Technology Partnership, developed a fiber optic communication capability for use in borehole applications. This environment requires the use of packaging and component technologies to operate at high temperature (up to 175{degrees}C) and survive rugged handling. Fiber optic wireline technology has been developed by The Rochester Corporation under contract to Sandia National Labs and produced a very rugged, versatile wireline cable. This development has utilized commercial fiber optic component technologies and demonstrated their utility in extreme operating environments.

Franco, R.J.; Morgan, J.R.

1997-04-01

400

Fiber optic communications fundamentals and applications  

CERN Document Server

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

Kumar, Shiva

2014-01-01

 
 
 
 
401

High-temperature fiber optic pressure sensor  

Science.gov (United States)

Attention is given to a program to develop fiber optic methods to measure diaphragm deflection. The end application is intended for pressure transducers capable of operating to 540 C. In this paper are reported the results of a laboratory study to characterize the performance of the fiber-optic microbend sensor. The data presented include sensitivity and spring constant. The advantages and limitations of the microbend sensor for static pressure measurement applications are described. A proposed design is presented for a 540 C pressure transducer using the fiber optic microbend sensor.

Berthold, J. W.

1984-01-01

402

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

1991-07-21

403

Stabilizing Fiber-Optic Transmission Lines  

Science.gov (United States)

Voltage-controlled optical phase shifter is key. Optical phase shifter stabilizes propagation delay of fiber-optic transmission line by compensating for temperature and pressure effects. Applicable to phased array antenna systems and very-long-baseline interferometer distribution systems.

Lutes, G. F.; Lau, K. Y.

1984-01-01

404

Extending the Real Remoteness of Long-Range Brillouin Optical Time-Domain Fiber Analyzers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The real remoteness of a distributed optical fiber sensor based on Brillouin optical time-domain analysis is considerably extended in this paper using seeded second-order Raman amplification and optical pulse coding. The presented analysis and the experimental results demonstrate that a proper optimization of both methods combined with a well-equalized two-sideband probe wave provide a suitable solution to enhance the signal-to-noise ratio of the measurements when an ultra-long sensing fiber ...

Soto, Marcelo A.; Angulo-vinuesa, Xabier; Martin-lopez, Sonia; Chin, Sang-hoon; Ania-castanon, Juan Diego; Corredera, Pedro; Rochat, Etienne; Gonzalez-herraez, Miguel; The?venaz, Luc

2014-01-01

405

Fiber optic sensor integration system and measurement technique  

Science.gov (United States)

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