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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

Fiber optic sensing and imaging  

CERN Document Server

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

2013-01-01

3

Fiber optic sensing system  

Science.gov (United States)

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

Adamovsky, Grigory (inventor)

1991-01-01

4

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

5

Optical Fiber Sensing Using Quantum Dots  

Directory of Open Access Journals (Sweden)

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

Faramarz Farahi

2007-12-01

6

Fiber Optical Sensing with Fiber Bragg Gratings  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A new measurement method is presented utilizing glass fibers with inscribed Fiber Bragg Gratings (FBG). Strain and temperature changes have direct effects on these gratings. With this technology and suitable transducers, however, also parameters like pressure, dislocation, vibration, acceleration, humidity and even chemicals can be monitored. A broadband or sweeping laser light source is used and light with wavelengths corresponding to the FBGs is reflected back to a data acquisition unit (in...

 eisenmann, T.

2010-01-01

7

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

8

Implementation of blind source separation for optical fiber sensing.  

Science.gov (United States)

Blind source separation (BSS) is implemented for optical fiber sensing systems, such as the fiber Bragg grating (FBG) sensing system and the single-mode-multimode-single-mode fiber (SMS) sensing system. The FastICA, a kind of multichannel BSS algorithm, is used to get the strain and the temperature with two FBGs. For the SMS sensing, a single-channel blind source separation (SCBSS) algorithm is employed to simultaneously measure the vibration and the temperature variation with only one SMS sensor. The errors of both the FBG and the SMS optical fiber sensing system are very small with the BSS algorithm. The implementation of BSS for the optical fiber sensing makes the multiparameter measurements more easily with low cost and high accuracy and can also be applied for signal de-noising field. PMID:24663460

Li, Qiang; Wang, Zhi; Huang, Zejia; Guo, Kaili; Liu, Lanlan

2014-03-20

9

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.

10

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 ...

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

2012-01-01

11

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

12

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

13

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

14

Fiber Optic Wing Shape Sensing on NASA's Ikhana UAV  

Science.gov (United States)

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

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

2008-01-01

15

Optical Fiber Sensing Using Quantum Dots  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2007-01-01

16

Extrinsic fiber optic displacement sensors and displacement sensing systems  

Energy Technology Data Exchange (ETDEWEB)

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

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

1994-01-01

17

Extrinsic fiber optic displacement sensors and displacement sensing systems  

Science.gov (United States)

An extrinsic Fizeau fiber optic sensor comprises a single-mode fiber, used as an input/output fiber, and a multimode fiber, used purely as a reflector, to form an air gap within a silica tube that acts as a Fizeau cavity. The Fresnel reflection from the glass/air interface at the front of the air gap (reference reflection) and the reflection from the air/glass interface at the far end of the air gap (sensing reflection) interfere in the input/output fiber. The two fibers are allowed to move in the silica tube, and changes in the air gap length cause changes in the phase difference between the reference reflection and the sensing reflection. This phase difference is observed as changes in intensity of the light monitored at the output arm of a fused biconical tapered coupler. The extrinsic Fizeau fiber optic sensor behaves identically whether it is surface mounted or embedded, which is unique to the extrinsic sensor in contrast to intrinsic Fabry-Perot sensors. The sensor may be modified to provide a quadrature phase shift extrinsic Fizeau fiber optic sensor for the detection of both the amplitude and the relative polarity of dynamically varying strain. The quadrature light signals may be generated by either mechanical or optical means. A plurality of the extrinsic sensors may connected in cascade and multiplexed to allow monitoring by a single analyzer. 14 figures.

Murphy, K.A.; Gunther, M.F.; Vengsarkar, A.M.; Claus, R.O.

1994-04-05

18

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

19

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Chin, Sanghoon; The?venaz, Luc

2013-01-01

20

Sensing characteristics of birefringent microstructured polymer optical fiber  

DEFF Research Database (Denmark)

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

Szczurowski, Marcin K.; Frazao, Orlando

2011-01-01

 
 
 
 
21

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

22

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

23

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

Science.gov (United States)

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

Warren-Smith, Stephen C; Monro, Tanya M

2014-01-27

24

Liquid Seal for Temperature Sensing with Fiber-Optic Refractometers  

Directory of Open Access Journals (Sweden)

Full Text Available Liquid sealing is an effective method to convert a fiber-optic refractometer into a simple and highly sensitive temperature sensor. A refractometer based on the thin-core fiber modal interferometer is sealed in a capillary tube filled with Cargille oil. Due to the thermo-optic effect of the sealing liquid, the high refractive-index sensitivity refractometer is subsequently sensitive to the ambient temperature. It is found that the liquid-sealed sensor produces a highest sensitivity of ?2.30 nm/°C, which is over 250 times higher than its intrinsic sensitivity before sealing and significantly higher than that of a grating-based fiber sensors. The sensing mechanisms, including the incidental temperature-induced strain effect, are analyzed in detail both theoretically and experimentally. The liquid sealing technique is easy and low cost, and makes the sensor robust and insensitive to the surrounding refractive index. It can be applied to other fiber-optic refractometers for temperature sensing.

Ben Xu

2014-08-01

25

Optical fiber current sensing based on Faraday effect in optical fiber  

Energy Technology Data Exchange (ETDEWEB)

Optical fiber current sensors based on the magnetooptic Faraday effect have been investigated as an alternative to conventional transformers. The Sagnac optical fiber current sensor by using a single mode fiber as a sensing medium is simpler than the polarimetric sensor with the input and output polarizer. Bur, the bending-induced linear birefringence existed in Sagnac loop reduces the long-term stability of Sagnac optical fiber current sensors. The stability of the Sagnac current sensors is also affected by vibration, stress, and temperature change. Two novel methods of stabilizing Sagnac current sensor developed in this work were presented. One method was realized by dividing the output of the ac current signal with the modulation signal output. As a result, the output of the sensor was stabilized within {+-}1.9%. The other method was characterized by creating an appropriate amount of circular birefringence into the Sagnac to remove the effect of the linear birefringence. We used a method of twisting a single mode fiber to induce a circular birefringence. The output of the sensor was stabilized within {+-}1.2% even under the application of pressing a portion of the fiber coil. When the twist-induced circular birefringence remains constant, the technique could be a good stabilization method. Bur, the twist-induced circular birefringence in single-mode fiber is sometimes temperature dependent. In this case, the output of the sensor drifts with temperature. To remove this drift problem, the twist-induced. circular birefringence needs to be readjusted as temperature changes. Here, we present another novel stabilization method which is realized by actively readjusting the twist-induced rotation angle to the maximum visibility point as the environmental condition changes. Employing the method, the stability of the sensor was demonstrated within {+-}1.7% even under the temperature change (36 deg C - 62 deg C). Also, the Sagnac current sensor shows good linearity up to 960 Arms. 30 refs., 19 figs. (author)

Lee, Kyung Sik; Kang, Hyun Seo; Lee, Jong Hun; Song Jung Tae; Lee Young Tak; Jung, Rae Sung [Sungkyunkwan University, Seoul (Korea, Republic of)

1997-07-01

26

Distributed measurement of chemicals using fiber optic evanescent wave sensing  

Science.gov (United States)

A truly distributed sensing system for nonpolar organic chemicals has been built up by adapting a chemically sensitive polymer-clad silica fiber to an optical time domain reflectometry (OTDR) set-up. This arrangement allows to measure the time delay between a short light pulse entering the fiber and the discrete signals of backscattered light caused by chemical effects in the fiber cladding. The backscatter signals originate from changes in the light guiding properties of the fiber, which are affected by the enrichment of chemicals in the cladding through the evanescent wave. The shape and magnitude of signals caused by penetrating chemicals either due to changes in refractive index, or absorption and fluorescence properties of the fiber cladding, have been examined. Changes in the optical properties of the cladding were produced either by contacting the fiber with solvents (e.g. tetrachloroethane) or organic dyes such as methylene blue and rhodamine 800. Typical parameters, that influence the intensity of the OTDR response signal are the refractive index, concentration and molar absorptivity of the analyte, as well as the power of the light source.

Buerck, Jochen; Sensfelder, Elke; Ache, Hans-Joachim

1996-12-01

27

Sensing principle of fiber-optic curvature sensor  

Science.gov (United States)

A novel fiber-optic sensor, which can measure curvature directly, has been developed in recent years. Its curvature measurement sensitivity is improved by a sensitive zone. To better understand the working principle and improve the performance of the sensor, the ray tracing simulation was carried out by using optical analysis software TracePro, which provides the sensing process for us. The results show that the rays will concentrate to the convex side of bent fiber. That is, the light intensity will increase at convex side and decrease at concave side, which leads to the changes of light leakage at sensitive zone and realizes the modulation to light intensity. The mathematic model of relationship among light loss, parameters of sensitive zone's configuration and bending curvature is presented.

Di, Haiting

2014-10-01

28

Optical trapping force and sensing detection research based on optical fiber shapes and transmission modes  

Science.gov (United States)

We consider the relationships between the optical trapping force of fiber optical tweezers and the different optical fiber modes and shapes. It is well known that the different optical fiber transmission modes and shapes can bring great influence to the light transmission. We calculate the radiation field of each model in the circle waveguide by using Huygens Fresnel principle. Then, based on the Maxwell Stress Tensor Integral, we can calculate the optical trapping force by using these radiation fields. Through the calculation and simulation, we explain the reason that the optical trapping force of fundamental mode is greater than the high modes in the case of having same shape of exit end face of a waveguide. At the same time, we explore the relationship between the optical trapping force and the fiber taper angles both in the fundamental mode and high modes. And we can obtain the maximum value of optical trapping force by optimizing the fiber taper angle. Optical fiber waveguides have the potential for integration of several functions including the sensing detection. Our results paved the road for utilizing the optical fiber waveguides in nano optical devices, optical trapping, and sensing.

Jiang, Hongmei; Liang, Yan; Cao, Pengfei; Shao, Qunfeng; Meng, Qingqing

2014-08-01

29

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

30

Chalcogenide Glass Fibers for Infrared Sensing and Space Optics  

Science.gov (United States)

This review deals with chalcogenide glasses and fibers. Chemical compositions and physical properties are given for specific glasses well suited for fiber drawing. Fabrication techniques of glass perform are described. Single-index and step-index single-mode fibers are characterized in terms of optical losses in the infrared. Examples of applications of chalcogenide fibers are given, as well as optical sensors in the fields of environment, microbiology and health, and as mode-filters for infrared interferometry in space.

Bureau, Bruno; Maurugeon, Sébastien; Charpentier, Frederic; Adam, Jean-Luc; Boussard-Plédel, Catherine; Zhang, Xiang-Hua

31

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

Science.gov (United States)

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

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

2009-03-01

32

CO2 laser ablation of bent optical fibers for sensing applications  

International Nuclear Information System (INIS)

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

33

Fiber optic device for sensing the presence of a gas  

Science.gov (United States)

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

34

High temperature fiber optic microphone having a pressure-sensing reflective membrane under tensile stress  

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 backplate for damping membrane motion. The backplate further provides a means for on-line calibration of the microphone.

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

1992-01-01

35

Distributed fiber optical sensing of oxygen with optical time domain reflectometry.  

Science.gov (United States)

In many biological and environmental applications spatially resolved sensing of molecular oxygen is desirable. A powerful tool for distributed measurements is optical time domain reflectometry (OTDR) which is often used in the field of telecommunications. We combine this technique with a novel optical oxygen sensor dye, triangular-[4] phenylene (TP), immobilized in a polymer matrix. The TP luminescence decay time is 86 ns. The short decay time of the sensor dye is suitable to achieve a spatial resolution of some meters. In this paper we present the development and characterization of a reflectometer in the UV range of the electromagnetic spectrum as well as optical oxygen sensing with different fiber arrangements. PMID:23727953

Eich, Susanne; Schmälzlin, Elmar; Löhmannsröben, Hans-Gerd

2013-01-01

36

Brief history of fiber optic sensing in the oil field industry  

Science.gov (United States)

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

Baldwin, Christopher S.

2014-06-01

37

Distributed and dynamical Brillouin sensing in optical fibers  

Science.gov (United States)

Employing stimulated Brillouin scattering (SBS), we present a novel method for the quasi-simultaneous distributed measurement of dynamic strain along an entire Brillouin-inhomogeneous optical fiber. Following classical mapping of the temporally slowly varying Brillouin gain spectrum (BGS) along the fiber, we use a specially synthesized and adaptable probe wave to always work on the slope of the local BGS, allowing a single pump pulse to sample fast strain variations along the entire fiber. Strain vibrations of tens of Hertz and up to 2KHz are demonstrated, simultaneously (i.e., using the same pump pulse) measured on two different segments of the fiber, having different static Brillouin shifts.

Peled, Yair; Motil, Avi; Yaron, Lior; Tur, Moshe

2011-05-01

38

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

Directory of Open Access Journals (Sweden)

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

Lee See Goh

2013-12-01

39

Theoretical study of high-sensitivity surface plasmon resonance fiber optic sensing technology  

Science.gov (United States)

Surface Plasmon Resonance (SPR) has been widely investigated for chemical and biological sensing applications. Especially, fiber optic SPR sensors have recently drawn considerable attention because of their fundamentally simpler structure, lower cost, and suitability for remote-sensing applications. This paper will present a research work for a novel multichannel SPR sensing technology. Based on the Kretschmann's SPR theory, we theoretically investigate the surface parameters effects to SPR wavelength changes. Emphasis will be placed on a theoretical design and numerical simulation of a multichannel fiber optic SPR sensing scheme based on a geometrical tapered fiber optic sensor probe that coated with nanoparticles imprinted polymer on the SPR sensing region. The parameter effects of SPR sensing area that include metal thickness, sensing area length and dielectric overcoat layer. SPR spectra that change with incidence angle and wavelength are investigated by using numerical calculations and simulations. While nanoparticles imprinted polymer for enhancement of sensitivity can serve as an enhanced transduction mechanism for recognition and sensing of target analytes in accordance with different requirements, the scheme of a multichannel fiber optic SPR sensor can be further adapted to the design and development of multi-channel optical fibers SPR sensor probes by combining SPR with other technology as a comprehensive sensor design.

Li, Hong; Jing, Zhenguo; Peng, Wei; Yu, Qi; Yao, Wenjuan; Hu, Lingling; Cheng, Huaqi

2011-08-01

40

Liquid Seal for Temperature Sensing with Fiber-Optic Refractometers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2014-01-01

 
 
 
 
41

Demodulation System for Fiber Optic Bragg Grating Dynamic Pressure Sensing  

Science.gov (United States)

Fiber optic Bragg gratings have been used for years to measure quasi-static phenomena. In aircraft engine applications there is a need to measure dynamic signals such as variable pressures. In order to monitor these pressures a detection system with broad dynamic range is needed. This paper describes an interferometric demodulator that was developed and optimized for this particular application. The signal to noise ratio was maximized through temporal coherence analysis. The demodulator was incorporated in a laboratory system that simulates conditions to be measured. Several pressure sensor configurations incorporating a fiber optic Bragg grating were also explored. The results of the experiments are reported in this paper.

Lekki, John D.; Adamovsky, Grigory; Floyd, Bertram

2001-01-01

42

Surface plasmon sensing of gas phase contaminants using optical fiber.  

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-10-01

43

Downhole fiber optic sensing: the oilfield service provider's perspective: from the cradle to the grave  

Science.gov (United States)

For almost three decades, interest has continued to increase with respect to the application of fiber-optic sensing techniques for the upstream oil and gas industry. This paper reviews optical sensing technologies that have been and are being adopted downhole, as well as their drivers. A brief description of the life of a well, from the cradle to the grave, and the roles fiber-optic sensing can play in optimizing production, safety, and protection of the environment are also presented. The performance expectations (accuracy, resolution, stability, and operational lifetime) that oil companies and oil service companies have for fiber-optic sensing systems is described. Additionally, the environmental conditions (high hydrostatic pressures, high temperatures, shock, vibration, crush, and chemical exposure) that these systems must tolerate to provide reliable and economically attractive oilfield monitoring solutions are described.

Skinner, Neal G.; Maida, John L.

2014-06-01

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

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

Science.gov (United States)

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

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

2014-03-31

46

Preliminary study of distributed optical fiber sensing technology in radiation monitoring  

International Nuclear Information System (INIS)

A decline of optical performance and corresponding loss originated when the optical fiber has been exposed in the radiation environment due to radiation-induced defects and the formation of color centers. According that, a conception of radiation monitoring system, based on distributed optical fiber single-end sensing technique,was introduced. It can be used to retrieve the dose of radiation by comparing light intensity of the output with the input. And space division multiplexing technology and many fiber-optic sensors are adopted to make multipoint supervision of nuclear power plants and nuclear arsenals and so on, where radioactive materials are concentrated, over large area. (authors)

47

Distributed Fiber Optical Sensing of Oxygen with Optical Time Domain Reflectometry  

Directory of Open Access Journals (Sweden)

Full Text Available In many biological and environmental applications spatially resolved sensing of molecular oxygen is desirable. A powerful tool for distributed measurements is optical time domain reflectometry (OTDR which is often used in the field of telecommunications. We combine this technique with a novel optical oxygen sensor dye, triangular-[4] phenylene (TP, immobilized in a polymer matrix. The TP luminescence decay time is 86 ns. The short decay time of the sensor dye is suitable to achieve a spatial resolution of some meters. In this paper we present the development and characterization of a reflectometer in the UV range of the electromagnetic spectrum as well as optical oxygen sensing with different fiber arrangements.

Elmar Schmälzlin

2013-05-01

48

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

International Nuclear Information System (INIS)

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

49

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

A method for seepage and settlement monitoring in earth embankment dams using fully distributed sensing along optical fibres is proposed. A model is developed for simulating and monitoring seepage and settlement systems. This model relates the strains and the temperature changes to the fiber Brillouin gain spectrum in the embankment dam embedding the optical fiber sensors. The model consists of two parts. Submodel 1 addresses the simulation of seepage inside the embankment dam. Submodel 2 rel...

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

2008-01-01

50

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2011-01-01

51

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

52

Thermal characterization of submicron polyacrylonitrile fibers based on optical heating and electrical thermal sensing  

International Nuclear Information System (INIS)

In this work, the thermal diffusivity of single submicron (?800 nm) polyacrylonitrile (PAN) fibers is characterized using the recently developed optical heating and electrical thermal sensing technique. In the experiment, a thin Au film (approximately in the nanometer range) is coated on the surface of nonconductive PAN fibers. A periodically modulated laser beam is used to irradiate suspended individual fibers to achieve noncontact periodical heating. The periodical temperature response of the sample is monitored by measuring the electrical resistance variation of the thin Au coating. The experimental results for three different synthesized PAN fibers with varying Au coating thickness are presented and discussed

53

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

54

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-03-01

55

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

International Nuclear Information System (INIS)

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

56

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

57

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

58

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

Science.gov (United States)

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

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

2013-09-01

59

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

Science.gov (United States)

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

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

2012-09-01

60

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

International Nuclear Information System (INIS)

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

 
 
 
 
61

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

62

Electrically Insulated Sensing of Respiratory Rate and Heartbeat Using Optical Fibers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Ernesto Suaste-Gómez; Daniel Hernández-Rivera; Sa?nchez-sa?nchez, Anabel S.; Elsy Villarreal-Calva

2014-01-01

63

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

Directory of Open Access Journals (Sweden)

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

Yoshitaka Takahashi

2011-12-01

64

Design and Fabrication of Fiber-Optic Nanoprobes for Optical Sensing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 aper...

Zhang Yan; Dhawan Anuj; Vo-Dinh Tuan

2010-01-01

65

Distributed sensing of hydrocarbons using evanescent wave interactions in a silicone-clad optical fiber  

Science.gov (United States)

A truly distributed sensing system for nonpolar organic chemicals is described which is built from a chemically sensitive polymer-clad silica fiber adapted to an optical time domain reflectometer (OTDR) set-up. This arrangement allows to measure the time delay between a short light pulse entering the fiber and the discrete signals of backscattered light caused by chemical effects in the fiber cladding. The light guiding properties of the fiber are affected by the enrichment of chemicals in the cladding through the evanescent wave. Changes in the refractive index (RI) of the cladding were produced by contacting the fiber with different solvents (e.g. dichloromethane, 1,1,1-trichloroethane or tetrachloroethene). Hydrocarbon compounds with a higher RI than the fiber cladding penetrating into the polysiloxane layer will increase the refractive index of the cladding and lead to a distinct step decrease in the OTDR response signal of the fiber at the position of enrichment. The size of the step decrease can be quantitatively correlated to the concentration of the hydrocarbon compound. Furthermore, the intensity of the OTDR response signal is dependent on the power of the light source and on the RI of the compound. By using a 5-W laser diode backscatter signals from tetrachloroethene in aqueous solution could be measured even at concentrations in the ppm range. The width of the step drop is linearly dependent on the interaction length between chemical and sensing fiber.

Buerck, Jochen; Sensfelder, Elke; Ache, Hans-Joachim

1997-05-01

66

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

Science.gov (United States)

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

Sastikumar, D.; Renganathan, B.

2014-11-01

67

SPR sensing with bimetallic layers in optical fibers and phase interrogation  

Science.gov (United States)

An analytical model based on geometrical optics and multilayer transfer matrix method is applied to determine the sensing properties of tapered optical fiber based SPR sensors incorporating bimetallic (Gold and Silver) layers, particularly when phase interrogation is considered. Phase interrogation is studied as a methodology to attain enhanced sensitivities. The performance of the sensing heads as function of the bimetallic layers and taper parameters is analyzed. It is shown the bimetallic combination is capable to provide larger values of sensitivity compared with the single layer approach. The results derived from this study are guiding the experimental study of these structures.

Moayyed, H.; Leite, I. T.; Coelho, L.; Santos, J. L.; Viegas, D.

2013-11-01

68

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-07-01

69

Long-distance fiber optic sensing solutions for pipeline leakage, intrusion, and ground movement detection  

Science.gov (United States)

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

Nikles, Marc

2009-05-01

70

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

71

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

72

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 Septemb...

Keller, C. A.; Huwald, H.; Vollmer, M. K.; Wenger, A.; Hill, M.; Parlange, M. B.; Reimann, S.

2011-01-01

73

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)

74

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

International Nuclear Information System (INIS)

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

75

Fiber Optic Sensors for Health Monitoring of Morphing Airframes. Part 2; Chemical Sensing Using Optical Fibers with Bragg Gratings  

Science.gov (United States)

Part 1 of this two part series described the fabrication and calibration of Bragg gratings written into a single mode optical fiber for use in strain and temperature monitoring. Part 2 of the series describes the use of identical fibers and additional multimode fibers, both with and without Bragg gratings, to perform near infrared spectroscopy. The demodulation system being developed at NASA Langley Research Center currently requires the use of a single mode optical fiber. Attempts to use this single mode fiber for spectroscopic analysis are problematic given its small core diameter, resulting in low signal intensity. Nonetheless, we have conducted a preliminary investigation using a single mode fiber in conjunction with an infrared spectrometer to obtain spectra of a high-performance epoxy resin system. Spectra were obtained using single mode fibers that contained Bragg gratings; however, the peaks of interest were barely discernible above the noise. The goal of this research is to provide a multipurpose sensor in a single optical fiber capable of measuring a variety of chemical and physical properties.

Wood, Karen; Brown, Timothy; Rogowski, Robert; Jensen, Brian

2000-01-01

76

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

77

A self-referencing intensity-based fiber optic sensor with multipoint sensing characteristics.  

Science.gov (United States)

A self-referencing, intensity-based fiber optic sensor (FOS) is proposed and demonstrated. The theoretical analysis for the proposed design is given, and the validity of the theoretical analysis is confirmed via experiments. We define the measurement parameter, X, and the calibration factor, ?, to find the transfer function, , of the intensity-based FOS head. The self-referencing and multipoint sensing characteristics of the proposed system are validated by showing the measured and relative error versus the optical power attenuation of the sensor head for four cases: optical source fluctuation, various remote sensing point distances, fiber Bragg gratings (FBGs) with different characteristics, and multiple sensor heads with cascade and/or parallel forms. The power-budget analysis and limitations of the measurement rates are discussed, and the measurement results of fiber-reinforced plastic (FRP) coupon strain using the proposed FOS are given as an actual measurement. The proposed FOS has several benefits, including a self-referencing characteristic, the flexibility to determine FBGs, and a simple structure in terms of the number of devices and measuring procedure. PMID:25046010

Choi, Sang-Jin; Kim, Young-Chon; Song, Minho; Pan, Jae-Kyung

2014-01-01

78

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

Directory of Open Access Journals (Sweden)

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

Sang-Jin Choi

2014-07-01

79

Fiber-optic high-temperature sensing system and its field application  

Science.gov (United States)

This paper presents the development of a sapphire-based fiber-optic sensing system for temperature monitoring in harsh environment, including sensor and system design, implementation, laboratory tests and field demonstration. The sensor is built with single-crystal sapphire fiber and sapphire wafer. As the sensing element, the wafer constitutes an extrinsic Fabry-Perot interferometer (EFPI) by its two surfaces. Its optical thickness has significant thermal dependence and provides temperature information through white light interferometry. The sensors were tested to 1600°C with 0.2% full scale accuracy and 0.5°C resolution. They were further demonstrated in industrial environment. A complete sensing system was developed around the sensor for temperature monitoring in a coal gasifier at the Tampa Electric Company's Polk Power Station. It consists of three major components: 1) Sensors and their packaging which were installed in the coal gasifier, 2) Optical interrogation unit for detection and transmission of sensor signal, and 3) Processing and control unit for signal demodulation. The system continuously operated and delivered temperature readings for seven months.

Zhu, Yizheng; Shen, Fabin; Huang, Zhengyu; Cooper, Kristie L.; Pickrell, Gary R.; Wang, Anbo; McDaniel, John; Pedro, Tim

2007-09-01

80

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

 
 
 
 
81

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

82

Fiber optic detector  

Energy Technology Data Exchange (ETDEWEB)

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

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

1990-12-31

83

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

84

Simultaneous strain and failure sensing of composite beam using an embedded fiber optic extrinsic Fabry-Perot sensor  

Science.gov (United States)

The fiber optic extrinsic Fabry-Perot sensor was embedded in composite beam to sense the strain and failure of composite structures. A tensile test was performed to confirm the strain sensitivity of the fiber optic sensor embedded in composite specimens. The strain sensitivity of the extrinsic Fabry-Perot sensor showed very good agreement with the theoretical value. The bending deformation and matrix cracking were investigated through four-point bending tests of cross-ply composite beams with embedded fiber optic extrinsic Fabry-Perot sensor. The failure due to matrix cracks in the composite beam was confirmed by an edge replica method. The strain and failure signals were separated by digital filtering from the signal of fiber optic sensor. The failure instants were obviously noticeable from the failure signal obtained from the fiber optic signal by high pass filtering. The dominant failure strain of the composite beam was determined by strain signal obtained by low pass filtering.

Hong, Chang-Sun; Kim, Chun-Gon; Kwon, Il-Bum; Park, Joong-Wan

1996-05-01

85

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

Directory of Open Access Journals (Sweden)

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

Gary Pickrell

2011-01-01

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

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

88

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

89

Distributed Fiber Optical Sensing of Oxygen with Optical Time Domain Reflectometry  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In many biological and environmental applications spatially resolved sensing of molecular oxygen is desirable. A powerful tool for distributed measurements is optical time domain reflectometry (OTDR) which is often used in the field of telecommunications. We combine this technique with a novel optical oxygen sensor dye, triangular-[4] phenylene (TP), immobilized in a polymer matrix. The TP luminescence decay time is 86 ns. The short decay time of the sensor dye is suitable to achieve a spatia...

Elmar Schmälzlin; Hans-Gerd Löhmannsröben; Susanne Eich

2013-01-01

90

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

Science.gov (United States)

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

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

2011-12-01

91

Magneto-optical garnet materials in fiber optic sensor systems for magnetic field sensing  

Science.gov (United States)

Magneto-optical garnet materials such as YIG, undoped as well as substituted, exhibit a large Faraday rotation. This fact makes them potentially suitable as sensing elements in fibre optic magnetic field sensor systems. We describe both an intensity based multimode system using bulk materials and a singlemode polarization based system using waveguiding films. A number of different material compositions, such as undoped YIG, (GdGa)- and different Bisubstituted YIG have been used for the sensor elements. Measurement results are presented and discussed. A detection limit in the xT range and a measurement range exceeding 10 have been achieved.

Svantesson, Kjell G.; Sohlstrom, Hans B.; Holm, Ulf

1990-08-01

92

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

International Nuclear Information System (INIS)

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

93

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...

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

2007-01-01

94

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

Science.gov (United States)

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

Prokop, Alexander; Wirbel, Anna

2013-04-01

95

Strain and failure sensing by the fiber optic Michelson sensor embedded in composite beam  

Science.gov (United States)

The bending deformation and matrix cracking were investigated by conducting a four-point bending test for a cross-ply composite beam with an embedded fiber optic Michelson sensor. The fiber optic Michelson interferometric sensor was constructed and embedded in the composite beam. The failure of composite beam, due to the matrix cracking, was successfully detected by the fiber optic sensor and the matrix crack in the composite beam was confirmed by an edge replica method. The characteristics of the failure signals from the fiber optic sensor were studied. The strain and failure signals of the composite beam were separated by digital filtering of the signal from the fiber optic sensor. The failure was obviously detectable by the failure signal filtered from the optical signal.

Hong, Chang-Sun; Kwon, Il-Bum; Kim, Chun-Gon

1996-04-01

96

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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. ...

Olivero, Massimo; Lousteau, Joris; Chen, Qiuping; Milanese, Daniel; Boetti, Nadia Giovanna; Chen, Qiuling

2012-01-01

97

Environmental temperature sensing using Raman spectra DTS fiber-optic methods  

Science.gov (United States)

Raman spectra distributed temperature sensing (DTS) by fiber-optic cables has recently shown considerable promise for the measuring and monitoring of surface and near-surface hydrologic processes such as groundwater-surface water interaction, borehole circulation, snow hydrology, soil moisture studies, and land surface energy exchanges. DTS systems uniquely provide the opportunity to monitor water, air, and media temperatures in a variety of systems at much higher spatial and temporal frequencies than any previous measurement method. As these instruments were originally designed for fire and pipeline monitoring, their extension to the typical conditions encountered by hydrologists requires a working knowledge of the theory of operation, limitations, and system accuracies, as well as the practical aspects of designing either short- or long-term experiments in remote or challenging terrain. This work focuses on providing the hydrologic user with sufficient knowledge and specifications to allow sound decisions on the application and deployment of DTS systems.

Tyler, Scott W.; Selker, John S.; Hausner, Mark B.; Hatch, Christine E.; Torgersen, Thomas; Thodal, Carl E.; Schladow, S. Geoffrey

2009-04-01

98

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

International Nuclear Information System (INIS)

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

99

Evaluation of optical fiber microcell reactor for use in remote acid sensing.  

Science.gov (United States)

An optical fiber acid-sensor based on protonation of a porphyrin solution within a single-hole structured optical fiber is proposed and demonstrated. The liquid-core fiber acts as a microcell reactor, and changes in the spectral signature with acidification are detected. Challenges and limitations in the practical deployment of such sensors are evaluated. An effective chemical sensor is demonstrated, but issues such as diffusion limit its full utilization. Some solutions are discussed. PMID:20237609

Huyang, George; Canning, John; Aslund, Mattias L; Stocks, Danial; Khoury, Tony; Crossley, Maxwell J

2010-03-15

100

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

 
 
 
 
101

Design and test research of a new optical fiber F-P humidity sensing system for modern agriculture environmental monitor  

Science.gov (United States)

Humidity monitoring is more and more emphasized on agriculture. Optical fiber humidity sensor has been paid great attention based on its excellent properties. In this paper, a novel method for the optic fiber F-P sensors based on the optimum double wavelength stabilization technique is put forward to use in humidity monitoring. The controlling system of work point which used for sensor stabilization is designed. DE algorithm stabilization model of sensing system is established. The working wavelength of DWDM and length of F-P cavity are calculated by the DE optimization design method. A sensing system with higher orthogonal precision is designed. The experimental setup of light route test is established. The results show that the light route performance of sensing system is well. This stabilization method is totally passive and offers a high resolution. It can satisfy the stabilization need of optical fiber F-P humidity sensor working point. DE algorithm can be used for the structural optimization design of optical fiber F-P humidity sensor.

Shan, Ning; Liu, Xia; Wang, Shaohua

102

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

Science.gov (United States)

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

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

2014-11-01

103

Heat Tracing Percolation in Managed Aquifer Recharge Facilities using Fiber Optic Distributed Temperature Sensing  

Science.gov (United States)

Percolation rates in Managed Aquifer Rechage (MAR) facilities, such as recharge basins and stream channels, can vary widely through both time and space. Natural variations in sediment hydraulic conductivity can create 'dead zones' in which percolation rates are negligible. Clogging is a constant problem, leading to decays in facility percolation rates . Measuring percolation rate variations is important for management, maintenance, and remediation of surface MAR facilities We have used Fiber Optic Distributed Temperature Sensing (FODTS) to monitor percolation in two very different recharge facilities. The first is a small (2 ha) nearly round recharge basin of homogeneous sediment type in which water balance can be closely monitored. The second is a long narrow river channel separated from an active river by a levee. The alluvial sediment in the river channel varies widely in texture and water balance is difficult to monitor independently. Both facilities were monitored by trenching in fiber optic cable and measuring the propagation rate of the diurnal temperature oscillations carried downward with infiltrating water. In this way, heat was used as a tracer of percolation rates along the section defined by the trenched cable (400 and 1600 m, respectively). We were able to confirm the FODTS measurements of percolation in the recharge basin and demonstrate its wide applicability in the river channel. Results from the measurements have been used to understand both the hydraulic behavior of percolation in the facilities and to make management decisions regarding facility operations and the potential need for additional surface sediment remediation. Estimation of specific discharge (m/day) through the basin using the wavelet method. Basin stage is shown above

Becker, M.; Ellis, W.; Bauer, B.; Hutchinson, A.

2013-12-01

104

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

105

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

106

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

107

An optical modulation method to suppress stimulated Brillouin scattering and the phase noise in a remote interferometric fiber sensing system  

Science.gov (United States)

A novel optical modulation method for stimulated Brillouin scattering (SBS) and the phase noise suppression in a remote interferometric fiber sensing system is proposed. Compared to the conventional phase modulation method to suppress SBS with only one phase modulation signal, another phase modulation signal with ? shift is applied at the output end of the fiber, which converts the generated multi-frequency light to single-frequency light. Therefore the method can suppress not only SBS but also the phase noise induced by linewidth broadening owing to the first phase modulation. As a result, the method can keep the system a low phase noise level with a higher input power, which overcomes the conventional drawback of linewidth broadening. The results show a good reference to the design of remote interferometric fiber sensing systems.

Hu, Xiaoyang; Chen, Wei; Fan, Liwen; Meng, Zhou; Chen, Mo

2014-10-01

108

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. Our approach towards immobilizing the potassium salt of the molybdenum cluster, K{sub 2}Mo{sub 6}Cl{sub 14}, at the far end of an optical fiber is to embed the cluster in a thermally cured sol-gel matrix particle. This particle-in-binder approach affords fibers with greatly improved mechanical properties, as compared to previous approaches. The sensor was characterized in 2-21% gas phase oxygen at 40, 70 and 100 C. 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; Po Zhang

2006-06-30

109

Development of optical fiber sensing instrument for aviation and aerospace application  

Science.gov (United States)

Optical fiber sensor has great advantage for applications dealing with extreme environment. We developed a high precision optical pressure sensor for aviation industry. The optical pressure sensor is based on two-beam interference of microcavity and is fabricated with Micro-electromechanical systems (MEMS) and laser fusion technology. The cavity length variation resulting from external pressure is demodulated with spatial polarization low coherence interference unit and a high stable phase demodulation algorithm. The effect of light source output parameter is also investigated. We carried out research on optical fiber strain, temperature and acoustic vibration sensor for aerospace application. The optical fiber sensors for strain and temperature measurement are based on fiber Bragg grating(FBG).Both bare FBG and packaged FBG performances under cryogenic temperature and high vacuum are investigated. An eight-channel parallel FBG wavelength interrogator is developed. The optical fiber acoustic vibration sensor is based on two-beam interference of microcavity and use intensity demodulation method for high speed response. The mutiple-parameter and multiplepoint measurement instrument is successfully applied to status monitoring of water sublimator.

Jiang, Junfeng; Liu, Tiegen; Liu, Kun; Wang, Shuang; Yin, Jinde; Zhao, Bofu; Zhang, Jingchuang; Song, Luyao; Zhao, Peng; Wu, Fan; Zhang, Xuezhi

2013-12-01

110

Fiber optic fluid detector  

Science.gov (United States)

Particular gases or liquids are detected with a fiber optic element (11, 11a to 11j) having a cladding or coating of a material (23, 23a to 23j) which absorbs the fluid or fluids and which exhibits a change of an optical property, such as index of refraction, light transmissiveness or fluoresence emission, for example, in response to absorption of the fluid. The fluid is sensed by directing light into the fiber optic element and detecting changes in the light, such as exit angle changes for example, that result from the changed optical property of the coating material. The fluid detector (24, 24a to 24j) may be used for such purposes as sensing toxic or explosive gases in the atmosphere, measuring ground water contamination or monitoring fluid flows in industrial processes, among other uses.

Angel, S. Michael (Livermore, CA)

1989-01-01

111

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. 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.

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

2004-10-01

112

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

113

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

Energy Technology Data Exchange (ETDEWEB)

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

Akimoto, Takuo [School of Bionics, Tokyo University of Technology, 1404-1 Katakura-machi, Hachiouji, 192-0982 Tokyo (Japan)], E-mail: akimoto@bs.teu.ac.jp; Wada, Syunsuke; Karube, Isao [School of Bionics, Tokyo University of Technology, 1404-1 Katakura-machi, Hachiouji, 192-0982 Tokyo (Japan)

2008-03-03

114

Optical Sensing using Fiber Bragg Gratings for Monitoring Structural Damage in Composite Over-Wrapped Vessels  

Science.gov (United States)

Composite Over-Wrap Vessels are widely used in the aerospace community. They are made of thin-walled bottles that are over wrapped with high strength fibers embedded in a matrix material. There is a strong drive to reduce the weight of space borne vehicles and thus pushes designers to adopt COPVs that are over wrapped with graphite fibers embedded in its epoxy matrix. Unfortunately, this same fiber-matrix configuration is more susceptible to impact damage than others and to make matters worse; there is a regime where impacts that damage the over wrap leave no visible scar on the COPV surface. In this paper FBG sensors are presented as a means of monitoring and detecting these types of damage. The FBG sensors are surface mounted to the COPVs and optically interrogated to explore the structural properties of these composite pressure vessels. These gratings optically inscribed into the core of a single mode fiber are used as a tool to monitor the stress strain relation in the composite matrix. The response of these fiber-optic sensors is investigated by pressurizing the cylinder up to its burst pressure of around 4500 psi. A Fiber Optic Demodulation System built by Blue Road Research, is used for interrogation of the Bragg gratings.

Grant, Joseph

2005-01-01

115

High-sensitivity temperature sensing using higher-order Stokes stimulated Brillouin scattering in optical fiber.  

Science.gov (United States)

In an effort to reduce the cost of sensing systems and make them more compact and flexible, Brillouin scattering has been demonstrated as a useful tool, especially for distributed temperature and strain sensing (DTSS), with a resolution of a few centimeters over several tens of kilometers of fiber. However, sensing is limited by the Brillouin frequency shift's sensitivity to these parameters, which are of the order of ~1.3??MHz/°C and of ~0.05??MHz/?? for standard fiber. In this Letter, we demonstrate a new and simple technique for enhancing the sensitivity of sensing by using higher-orders Stokes shifts with stimulated Brillouin scattering (SBS). By this method, we multiply the sensitivity of the sensor by the number of the Stokes order used, enhanced by six-fold, therefore reaching a sensitivity of ~7??MHz/°C, and potentially ~0.30??MHz/??. To do this, we place the test fiber within a cavity to produce a frequency comb. Based on a reference multiorder SBS source for heterodyning, this system should provide a new distributed sensing technology with significantly better resolution at a potentially lower cost than currently available DTSS systems. PMID:24562225

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

2014-02-15

116

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. Our approach towards immobilizing the potassium salt of the molybdenum cluster, K{sub 2}Mo{sub 6}Cl{sub 14}, at the far end of an optical fiber is to embed the cluster in a thermally cured sol-gel matrix particle. Due to the improved mechanical properties of this approach high temperature sensor measurements were performed up to 100 C. 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; Po Zhang

2006-09-30

117

Potential of the active heat pulse method with fiber optic temperature sensing for estimation of water content and infiltration in agricultural soils  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The principle of temperature measurement along a fiber optic cable is based on the thermal sensitivity of the relative intensities of backscattered Raman Stokes and anti Stokes photons that arise from collisions with electrons in the core of the glass fiber. A laser pulse, generated by the Distributed Temperature Sensing unit DTS, traversing a fiber optic cable will result in Raman backscatter at two frequencies, referred to as Stokes and anti-Stokes.

Sayde, C.; Selker, J.; English, M.; Rodri?guez Sinobas, Leonor; Gil Rodri?guez, Mari?a; Sa?nchez Calvo, Rau?l; Benitez Buelga, Javier

2010-01-01

118

Multimaterial photosensitive fiber constructs enable large-area optical sensing and imaging  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The process of optical imaging and the use of a glass lens have been hitherto inseparable since it is the lens that is responsible for mapping incoming rays to form an image. While performing this critical role, the lens, by virtue of its geometry and materials composition, presents constraints on the size, weight, angular field of view, and environmental stability of an optical imaging system as a whole. Here, a new approach to optical imaging is presented. Tough polymeric light-sensing fibe...

Abouraddy, Ayman F.; Fink, Yoel

2009-01-01

119

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% 240Pu). The system noise base was about 0.2 rad, equivalent to about 1 mg of plutonium

120

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% 240Pu). The system noise base was about 0.2 rad, equivalent to about 1 mg of plutonium

 
 
 
 
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 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

122

Research on acoustical properties of the femtosecond laser ablation targets using fiber optic sensing probe  

Science.gov (United States)

The acoustic signals of the laser micro plasma expansion for the femtosecond laser ablating pure Al, Cu and Fe target materials have been detected by the fiber Fabry-Perot (F-P) acoustic emission sensing probe. The frequency and amplitude of the acoustic emission spectrum have been analyzed. The results show that the detected acoustic emission frequency spectrum pattern is fixed and different for the three kinds of target materials. The amplitude of the acoustic emission spectrum grows up along with the enhancement of laser ablation energy. The amplitude of the acoustic emission spectrum decreases when the detection distance is enlarged. The developed measuring system provides a potential method aiming at the detection of solid materials based on the acoustic signals excided by femtosecond laser ablating target materials using the fiber F-P acoustic emission sensing probe.

Zhong, Dong; Tong, Xinglin; Wen, Xiaoyan; Jiang, Desheng; Mao, Yan; Li, Yan

2015-01-01

123

A compact fiber optic accelerator  

Science.gov (United States)

A compact fiber optic Michelson interferometer based accelerometer is proposed and demonstrated. In this sensing system, two optical fibers have been used as the differential sensing element. By way of demodulating the different optical phase, we can obtain the acceleration which proportional to the initial force applied on the central position of the two fibers. A simple model has been built to calculate the sensitivity and resonant frequency. The experimental results show that such an accelerometer has a sensitivity of 0.42rad/g at the resonant frequency 600Hz.

Peng, Feng; Li, Xingliang; Wu, Bing; Yuan, Yonggui; Yang, Jun; Yuan, Libo

2011-05-01

124

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

DEFF Research Database (Denmark)

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

Markos, Christos; Stefani, Alessio

2013-01-01

125

Assessing the efficiency and detection limits of Fiber-Optic Distributed Temperature Sensing in environmental applications  

Science.gov (United States)

The use of Fiber-optic Distributed Temperature Sensing (FO-DTS) for the temporal and spatial measurement of transient/discrete changes in temperature continuously has seen a substantial increase in the environmental and hydrological sector. Popular hydrological applications of FO-DTS involve the monitoring of stream or streambed temperature dynamics, groundwater inflow patterns and stream/groundwater interaction. The temperature and sampling resolution of currently available FO-DTS instruments typically vary between 1-2m and 0.01°C with the most advanced systems providing spatial measurement resolutions of 0.25m. Temporal resolutions vary upwards from fractions of a minute (when a standard communication fiber-optic cable is used) for cable lengths of up to 30,000 m. FO-DTS technology has been applied to the measurement of both, continuous temperature changes over larger scales as well as discrete hot- or cold spots at small scales. For accurately measuring temperatures by FO-DTS, it is important to account for the aforementioned limitations during the monitoring set up. In order to ensure that the actual signal size and location are accurately reflected by the FO-DTS measurements, it is essential to prove that the spatial extent of the investigated signal variation can be captured by the DTS methodology. If detection limits and uncertainties are not considered thoroughly during the monitoring set up, the resulting errors can fundamentally affect the interpretation of the results. As such, it is essential that the spatial dependency of FO-DTS signal accuracy is understood (i.e., its ability to predict the actual magnitude temperature as well as the relative spatial location of the signal) in order to provide data which are reliable and comparable with other methods for temperature monitoring. This study presents an analysis of FO-DTS measurement precision based on the prediction of signal strength and location in relation to signal size and measurement set up. Using a DTS instrument with a spatial sampling resolution of 2m and a standard fibre-optic cable set up, measurements of 'warmer' (40±4oC) and colder (0±3oC) water bath temperatures were made in comparison to ambient 25oC. Spatial measurement increments ranged between 0.25m and 15m and the results investigated for accuracy in their prediction of magnitude (temperature) and location. The results showed that signals of the size of up to 3-times of the sampling interval would still be captured with substantial uncertainties in the signal magnitude (i.e., temperature). Although FO-DTS technology, and in particular spatial resolution of measurements, are fast advancing, the results prove that care is needed when interpreting discrete signal changes with spatial extents close to the sampling resolution. Ultimately, any limitations in the instrument precision and in the monitoring set up may limit the applicability of this exciting technology for precisely predicting small signal changes at small scales.

Rose, L.; Krause, S.; Cassidy, N.

2012-04-01

126

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

Science.gov (United States)

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

Lefèvre, Hervé C.

2014-12-01

127

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. Alkali salts of Mo{sub 6}Cl{sub 12} were synthesized and heated to 280 C for one hour in air. Optical measurements of the thermally treated material confirm the potential of the salts as lumophores in high temperature fiber optic sensors. In addition sol-gel films containing Mo{sub 6}Cl{sub 12} were dip coated on quartz substrates and heated at 200 C for one hour. Conditions were developed for successfully immobilizing monomeric complexes that are compatible with sol-gel processing.

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

2004-07-01

128

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

129

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

Science.gov (United States)

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

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

2014-09-01

130

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

131

Fiber optic calorimetry  

Energy Technology Data Exchange (ETDEWEB)

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 ({mu}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% {sup 240}Pu). The system noise base was about 0.2 rad, equivalent to about 1 mg of plutonium.

Rudy, C.; Bayliss, S.; Bracken, D. [Los Alamos National Lab., NM (United States); Bush, J.; Davis, P. [Optiphase, Inc., Van Nuys, CA (United States)

1998-01-01

132

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

133

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

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

2005-04-01

134

Optical fibre sensing of plasmas  

International Nuclear Information System (INIS)

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

135

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

CERN Document Server

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

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

2015-01-01

136

Optical fiber-tip Fabry-Perot interferometer for hydrogen sensing  

Science.gov (United States)

A novel optical fiber-tip Fabry-Perot interferometer (FPI) coated with Pt/WO3 film was demonstrated as a hydrogen sensor. The air-cavity of FPI was formed by inserting a single mode fiber (SMF) into a partially polymer-filled glass capillary. A layer of Pt/WO3 was coated on the capillary of the FPI serving as a reaction heater upon hydrogen exposure. The heat locally raised the FPI temperature, which led to the length of air-cavity decrease due to the volume expansion of polymer. Thus, the dip wavelength of interference spectrum yielded a blue shift. The temperature compensation method based on an optical switch was proposed to eliminate the effect of ambient temperature fluctuation. Experimental investigations demonstrated a high sensitivity of -5.1 nm/% at a low hydrogen concentration ranging from 0% to 0.5%.

Zhang, Guilin; Yang, Minghong; Wang, Yao

2014-10-01

137

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

International Nuclear Information System (INIS)

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

138

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

Energy Technology Data Exchange (ETDEWEB)

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

Chandler, G.I.; Jahoda, F.C.

1983-01-01

139

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

International Nuclear Information System (INIS)

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

140

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

 
 
 
 
141

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

Directory of Open Access Journals (Sweden)

Full Text Available Fiber loop ringdown (FLRD has demonstrated to be capable of sensing various quantities, such as chemical species, pressure, refractive index, strain, temperature, etc.; and it has high potential for the development of a sensor network. In the present work, we describe design and development of three different types of FLRD sensors for water, cracks, and temperature sensing in concrete structures. All of the three aforementioned sensors were indigenously developed very recently in our laboratory and their capabilities of detecting the respective quantities were demonstrated. Later, all of the sensors were installed in a test grout cube for real-time monitoring. This work presents the results obtained in the laboratory-based experiments as well as the results from the real-time monitoring process in the test cube.

Chuji Wang

2013-06-01

142

Strain measurement in concrete structure using distributed fiber optic sensing based on Brillouin scattering with single-mode fibers embedded in glass fiber reinforcing vinyl ester rod and bonded to steel reinforcing bars  

Science.gov (United States)

The strain distribution in a 1.65m long reinforced concrete beam was measured using the distributed fiber optic sensing system developed by Dr. Bao's Fiber Optic Group at the University of New Brunswick (UNB) with center point and two point loading pattern. A spatial resolution of 0.5m was used. Past experience has shown that the bare optical fiber is too fragile to act as a sensor in a reinforced concrete structure. Therefore, in this experiment, two methods of protecting the fibers were incorporated into the concrete beam to increase the fibers' resistance to mechanical damages and prevent chemical reaction from occurring between the fibers and the concrete. The fibers were either embedded in pultruded glass fiber reinforced vinyl ester (GFRP) rods or bonded to the steel reinforcing bars with an epoxy adhesive. The strain at midspan of the beam as measured by the distributed sensing system was compared with the readings of electrical resistance strain (ERS) and mechanical strain (MS) gauges. The experimental results showed that the pultruded GFRP rods effectively protected the fibers, but the strain readings from the GFRP rods did not agree with the strain measurement of the ERS on the steel reinforcing bars due to the possible slippage of the rods in the concrete. However, the fiber bonded to steel reinforcing bars produced more accurate results and confirmed the potential of this technology to accurately measure strain in a reinforced concrete structure. As expected, the fiber with direct contact to the concrete and steel reinforcing bar, can effectively measured the strain under center point or two point loading.

Chhoa, Cia Y.; Bao, Xiaoyi; Bremner, Theodore W.; Brown, Anthony W.; DeMerchant, Michael D.; Kalamkarov, Alexander L.; Georgiades, Anastasis V.

2001-08-01

143

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

144

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

Science.gov (United States)

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

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

2009-03-15

145

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

146

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

International Nuclear Information System (INIS)

Optical fiber sensors (OFSs) have many advantages like flexible configuration, intrinsic immunity for electromagnetic fields, and so on. For these reasons, it is very useful to apply OFSs to fast reactor plants for remote inspection and surveillance. However, under irradiation, because of radiation-induced transmission loss of optical fibers, OFSs have radiation-induced errors. Therefore, to apply OFSs to nuclear facilities, we have to estimate and correct the errors. In this report, Raman Distributed Temperature Sensor (RDTS; one of the OFSs) has been installed at the primary coolant loop of the experimental fast reactor JOYO of JNC (Japan Nuclear Cycle Development Institute). Two correction techniques (correction technique with two thermocouples and correction technique with loop arrangement) for radiation-induced errors have been developed and demonstrated. Because of the radiation-induced loss, measured temperature distributions had radiation-induced errors. However, during the continuous measurements with the total dose of more than 8 x 103[C/kg](3 x 107[R]), the radiation induced errors showed a saturation tendency. In case of the temperature distributions with fluorine doped fiber, with one of the correction techniques, the temperature errors reduced to 1?2degC and the feasibility of the loss correction techniques was demonstrated. For these results, it can be said that RDTS can be applied as a temperature distribution monitor in harsh radiation environments like fast reactor plants. (author)

147

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-12-01

148

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

149

Annealing of silicon optical fibers  

Science.gov (United States)

The recent realization of silicon core optical fibers has the potential for novel low insertion loss rack-to-rack optical interconnects and a number of other uses in sensing and biomedical applications. To the best of our knowledge, incoherent light source based rapid photothermal processing (RPP) was used for the first time to anneal glass-clad silicon core optical fibers. X-ray diffraction examination of the silicon core showed a considerable enhancement in the length and amount of single crystallinity post-annealing. Further, shifts in the Raman frequency of the silicon in the optical fiber core that were present in the as-drawn fibers were removed following the RPP treatment. Such results indicate that the RPP treatment increases the local crystallinity and therefore assists in the reduction of the local stresses in the core, leading to more homogenous fibers. The dark current-voltage characteristics of annealed silicon optical fiber diodes showed lower leakage current than the diodes based on as-drawn fibers. Photons in UV and vacuum ultraviolet (VUV) regions play a very important role in improving the bulk and carrier transport properties of RPP-treated silicon optical fibers, and the resultant annealing permits a path forward to in situ enhancement of the structure and properties of these new crystalline core optical fibers.

Gupta, N.; McMillen, C.; Singh, R.; Podila, R.; Rao, A. M.; Hawkins, T.; Foy, P.; Morris, S.; Rice, R.; Poole, K. F.; Zhu, L.; Ballato, J.

2011-11-01

150

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. The luminescence of Mo{sub 6}Cl{sub 12} immobilized in a sol-gel matrix was measured as a function of heater temperature up to 200 C, in an inert environment. While the luminescence decreased with temperature, the integrated intensity at 200 C should be sufficient to enable detection of the luminescence in a fiber geometry. Previously we found that aging Mo{sub 6}Cl{sub 12} at temperatures above 250 C converts the canary yellow Mo{sub 6}Cl{sub 12} to a non-luminescent gray solid. Optical and thermal aging experiments show that the alkali metal salts of Mo{sub 6}Cl{sub 12} have higher thermal stabilities and remain luminescent after aging at 280 C.

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

2004-04-01

151

Omnidirectional fiber optic tiltmeter  

Science.gov (United States)

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

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

1983-06-30

152

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

Energy Technology Data Exchange (ETDEWEB)

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

Challener, William

2014-12-31

153

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

Scientific Electronic Library Online (English)

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

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

2010-06-01

154

Detection of plasma equilibrium shifts with fiber optic sensing of image currents  

Energy Technology Data Exchange (ETDEWEB)

The radial equilibrium position of Reverse Field Pinch experiments is determined by the j x B force on the plasma. The current density is that of the toroidal plasma current and the B field is the vertical magnetic field which is present in the plasma. This magnetic field is the result of several components. The main field, generated by the toroidal current windings, is corrected by adjustable trim windings to achieve a desired equilibrium position. There is an additional component to the field due to induced image currents in the close fitting conducting shell which encircles the plasma. These currents vary in time due to the finite L/R time of the conducting shell. It is the object of this paper to investigate the possibility of measuring these shell currents accurately using fiber optics so as to provide an analog signal to the equilibrium feedback circuit. 7 refs., 7 figs.

Forman, P.R.; Jahoda, F.C.; Miller, G.

1988-01-01

155

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

156

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

157

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

158

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

159

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...

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

2012-01-01

160

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.

 
 
 
 
161

Subsea downhole optical sensing  

Science.gov (United States)

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.

McStay, D.; Shiach, G.; McAvoy, S.

2009-07-01

162

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

Directory of Open Access Journals (Sweden)

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

Abdul Samee Khan

2012-09-01

163

Fiber optic plenum cable  

Science.gov (United States)

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

Angeles, Purita; Kurt, Jeffrey

1986-11-01

164

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

165

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

Science.gov (United States)

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

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

2015-02-01

166

[Determination of intrinsic alliin dissolution rates with fiber-optic sensing process analysis].  

Science.gov (United States)

The apparatus for intrinsic dissolution test recorded in United States Pharmacopeia (USP) integrating with fiber-optic drug dissolution test system (FODT) were used to real-time monitor intrinsic dissolution processes of alliin in four media which were water, solution of HCl with pH 1.2, buffer solution of acetate with pH 4.5, and buffer solution of phosphate with pH 6.8. The intrinsic dissolution rate (IDR) and the similarity factor (f2) of two intrinsic dissolution curves with two apparatuses were calculated. The IDR values of alliin with rotating disk system were 28.1.3, 33.55, 28.38 and 30.95 mg x cm(-2) x min(-1) in four media, respectively. And the IDR values of alliin with stationary disk system were 44.16, 47.07, 45.11 and 51.34 mg x cm(-2) x min(-1), respectively. The similarity factors were 56.42, 50.75, 40.30 and 40.64, respectively. The results showed that the intrinsic alliin dissolution rates were much greater than 1 mg x cm(-2) x min(-1). It inferred that alliin dissolution would not be the rate limiting step to absorption. PMID:25577881

Geng, Jing; Zhang, Zi-Cheng; Zhang, Hai-Bo; Li, Xin-Xia; Chen, Jian

2014-10-01

167

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

Science.gov (United States)

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

Lan, Chunguang; Zhou, Zhi; Ou, Jinping

2012-01-01

168

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

169

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

170

Advanced fiber-optic acoustic sensors  

Science.gov (United States)

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

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

2014-09-01

171

Polarization in optical fibers  

CERN Document Server

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

172

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

International Nuclear Information System (INIS)

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

173

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

174

Multimode optical fiber  

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-11-04

175

Superlattice Microstructured Optical Fiber  

Directory of Open Access Journals (Sweden)

Full Text Available A generic three-stage stack-and-draw method is demonstrated for the fabrication of complex-microstructured optical fibers. We report the fabrication and characterization of a silica superlattice microstructured fiber with more than 800 rhomboidally arranged air-holes. A polarization-maintaining fiber with a birefringence of 8.5 × 10?4 is demonstrated. The birefringent property of the fiber is found to be highly insensitive to external environmental effects, such as pressure.

Ming-Leung Vincent Tse

2014-06-01

176

Woven fiber optics.  

Science.gov (United States)

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

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

1975-02-01

177

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

Science.gov (United States)

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

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

2010-09-27

178

Fiber Optic Level Sensor  

Science.gov (United States)

A system has been developed which permits the remote non-contact sensing of the correct fill level of granular, diffuse scattering materials where electrical connections may pose a hazard. The system consists of a sensor head, a fiber optic cable containing three low-loss fibers, and a small console which contains the light source, detector and all electrical and electronic components. The system uses a pair of nearly collimated parallel light beams to define a pair of lines in space, which are intersected at a small angle by the field of view of the detection system. The midpoint between the two intersections is the position at which a scattering surface produces equal intensity signals at the detector from the two beams. The distance below the sensor head at which the intersection occurs defines the level at which valve closing signal is generated. In order to label the light beams, a chopper modulates the two beams 90° out of phase. This permits separation of an automatic gain control signal to virtually remove dependence on the absorbance of the scattering material, as well as permitting independent measures of the two backscatter signals which activate a comparator when the relative scattering intensity from the nearer beam exceeds that from the further beam. Within the defined operating range, the reproducibility of trip level is about +/-0.7% at a range of about 300mm.

Unterleitner, Fred C.

1983-11-01

179

Radiochromic gel-core fluorinated-polyethylene-propylene fiber optics for distributed sensing of X and gamma rays  

Science.gov (United States)

A novel fiber optic sensor responds with a supra-linear relationship between optical density readout and absorbed dose, when irradiated with high doses of x and gamma radiation (10-2 to 104 Gy). The radiation sensor medium is a radiochromic gel core filling a flexible fluorinated polyethylene plastic tubing that is fitted with either Suprasil quartz plugs as radiation-insensitive end windows or Pyrex glass beads that serve as lenses. Readings are made with a specially designed spectrophotometer enabling efficient propagation of interrogating light with a narrow band-pass filter at the optical wavelength of the radiation-induced color absorption band maximum (600 nm). The absorption at 600 nm is related to the formation of a highly conjugated carbocationic dye. The formation of the conjugation proceeds through very fast kinetics (approximately 1 ns) followed by relatively slower kinetics (2 ms). The shortest selective fiber optic sensor length is 5 cm and outer diameter is 0.27 cm, allowing selective placement of the sensor portion into remote irradiated components. Fiber optic sensor lengths up to 150 cm allow dose measurements as low as 10 -2 Gy. Extraction of radiation dosimetry data to the external reader is carried out either in real-time or on demand following irradiation, and is made possible by connecting the sensor length to ancillary fiber optic access loop.

Al-Sheikhly, Mohamad; McLaughlin, William L.; Hsu, Chun-Keng; Christou, Aristos

1996-10-01

180

Optical fiber spectrophotometer  

International Nuclear Information System (INIS)

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

 
 
 
 
181

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

Science.gov (United States)

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

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

2014-06-01

182

Optical fiber head for providing lateral viewing  

Science.gov (United States)

The head of an optical fiber comprising the sensing probe of an optical heterodyne sensing device includes a planar surface that intersects the perpendicular to axial centerline of the fiber at a polishing angle .theta.. The planar surface is coated with a reflective material so that light traveling axially through the fiber is reflected transverse to the fiber's axial centerline, and is emitted laterally through the side of the fiber. Alternatively, the planar surface can be left uncoated. The polishing angle .theta. must be no greater than 39.degree. or must be at least 51.degree.. The emitted light is reflected from adjacent biological tissue, collected by the head, and then processed to provide real-time images of the tissue. The method for forming the planar surface includes shearing the end of the optical fiber and applying the reflective material before removing the buffer that circumscribes the cladding and the core.

Everett, Matthew J. (Livermore, CA); Colston, Billy W. (Livermore, CA); James, Dale L. (Tracy, CA); Brown, Steve (Livermore, CA); Da Silva, Luiz (Danville, CA)

2002-01-01

183

Polymer optical fiber fuse  

CERN Document Server

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

Mizuno, Yosuke; Tanaka, Hiroki; Nakamura, Kentaro

2013-01-01

184

Characterizing fractured rock aquifers using heated Distributed Fiber-Optic Temperature Sensing to determine borehole vertical flow  

Science.gov (United States)

In highly heterogeneous media, fracture network connectivity and hydraulic properties can be estimated using methods such as packer- or cross-borehole pumping-tests. Typically, measurements of hydraulic head or vertical flow in such tests are made either at a single location over time, or at a series of depths by installing a number of packers or raising or lowering a probe. We show how this often encountered monitoring problem, with current solutions sacrificing either one of temporal or spatial information, can be addressed using Distributed Temperature Sensing (DTS). Here, we electrically heat the conductive cladding materials of cables deployed in boreholes to determine the vertical flow profile. We present results from heated fiber optic cables deployed in three boreholes in a fractured rock aquifer at the much studied experimental site near Ploemeur, France, allowing detailed comparisons with alternative methods (e.g. Le Borgne et al., 2007). When submerged in water and electrically heated, the cable very rapidly reaches a steady state temperature (less than 60 seconds). The steady state temperature of the heated cable, measured using the DTS method, is then a function of the velocity of the fluid in the borehole. We find that such cables are sensitive to a wide range of fluid velocities, and thus suitable for measuring both ambient and pumped flow profiles at the Ploemeur site. The cables are then used to monitor the flow profiles during all possible configurations of: ambient flow, cross-borehole- (pumping one borehole, and observing in another), and dipole-tests (pumping one borehole, re-injection in another). Such flow data acquired using DTS may then be used for tomographic flow inversions, for instance using the approach developed by Klepikova et al., (submitted). Using the heated fiber optic method, we are able to observe the flow response during such tests in high spatial detail, and are also able to capture temporal flow dynamics occurring at the start of both the pumping and recovery phase of cross-borehole- and dipole- tests. In addition, the clear advantage of this is that by deploying a single fiber optic cable in multiple boreholes at a site, the flow profiles in all boreholes can be simultaneously measured, allowing many different pumping experiments to be conducted and monitored in a time efficient manner. Klepikova M. V., Le Borgne T., Bour O., and J-R.de Dreuzy, Inverse modelling of flow tomography experiments in fractured media, submitted to Water Resources Research. Le Borgne T., Bour O., Riley M. S., Gouze P., Pezard P.A., Belghoul A., Lods G., Le Provost R., Greswell R. B., Ellis P.A., Isakov E., and B. J. Last, Comparison of alternative methodologies for identifying and characterizing preferential flow paths in heterogeneous aquifers. Journal of Hydrology 2007, 345, 134-148.

Read, T. O.; Bour, O.; Selker, J. S.; Le Borgne, T.; Bense, V.; Hochreutener, R.; Lavenant, N.

2013-12-01

185

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

186

A fiber optic sensor for nerve agent  

Science.gov (United States)

We report advances made on the development of a fiber optic nerve agent sensor having its entire length as the sensing element. The optical fiber is multimode, and consists of a fused-silica core and a nerve agent sensitive cladding. Upon exposure to sarin gas, the cladding changes color, resulting in an alteration of the light intensity throughput. The fiber is mass produced using a conventional fiber optic draw tower. This technology could replace, or be used with, a collection of point-detectors to protect personnel, buildings and perimeters from dangerous chemical attacks.

Cordero, Steven R.; Mukamal, Harold; Low, Aaron; Locke, Edward P.; Lieberman, Robert A.

2006-10-01

187

Optical fiber interferometric spectrometer  

Science.gov (United States)

We design an optical fiber spectrometer based on optical fiber Mach-Zehnder interferometer. In optical fiber Fourier transform spectrometer spectra information is obtained by Fourier transform of interferogram, which recording intensity change vs. optical path difference. Optical path difference is generated by stretching one fiber arm which wound around fiber stretch drive by high power supply. Information from detector is linear with time rather than with optical path difference. In order to obtain high accuracy wavenumber, reference beam is used to control the optical path difference. Optical path difference is measured by reference laser interference fringe. Interferogram vs. optical path difference is resampled by Brault algorithm with information from reference beam and test beam. In the same condition, one-sided interferogram has higher resolution than that of two-sided interferogram. For one-sided interferogram, zero path difference position must be determined as accurately as possible, small shift will result in phase error. For practical experiment in laboratory, position shift is inevitable, so phase error correction must be considered. Zero order fringe is determined by curve fitting. Spectrum of light source is obtained from one-sided interferogram by Fourier cosine transform. A spectral resolution of about ~3.1 cm -1 is achieved. In practice, higher resolution is needed. This compact equipment will be used in emission spectra and absorption spectra, especially in infrared region.

Liu, Yong; Li, Baosheng; Liu, Yan; Zhai, Yufeng; Wang, An

2006-02-01

188

Liquid Crystal Devices for Optical Communications and Sensing Applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis is focussed on the design and development of liquid crystal based tunable photonic devices for applications in optical communications and optical sensing, with an emphasis on all-fiber device configuration. The infiltration of liquid crystals into photonic crystal fiber provides a suitable common platform to design and fabricate simple and compact all-fiber tunable photonic devices which can be easily integrated with optical fiber networks and sensing systems. Based on the infiltr...

Mathews, Sunish

2011-01-01

189

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Chunguang Lan; Zhi Zhou; Jinping Ou

2012-01-01

190

Fiber optics dosimetry  

Science.gov (United States)

Nuclear radiation induced darkening of optical fibers has been employed to extend the range of glass dosimetry to that of personal dosimetry. Dosimeters constructed using this principle have proved sufficiently rugged and reliable for civil defense applications.

Kronenberg, Stanley; Siebentritt, Carl R.

1980-09-01

191

Optical Waveguide Sensing and Imaging  

CERN Document Server

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

Bock, Wojtek J; Tanev, Stoyan

2008-01-01

192

Self focusing optical fiber  

International Nuclear Information System (INIS)

The invention relates to the field of optoelectronics and may be used in the fiber/optic data transmission systems. Summary of the invention consists in that the self focusing optical fiber contains a shell with a core, placed between two control electrodes. With that the shell is made in the form of a plastic tube, and the core - in the form of a colloidal suspention of PbTiO3 and SrTiO3 powders in the polyethilsiloxane oil

193

Optical remote sensing  

CERN Document Server

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

Prasad, Saurabh; Chanussot, Jocelyn

2011-01-01

194

Vapor sensing properties of carbon nanotubes onto cadmium arachidate multilayer investigated by optical-fiber-based reflectometer sensor and acoustic sensors  

Science.gov (United States)

We have investigated the sensing properties of the carbon nanotubes deposited onto a cadmium arachidate buffered multilayer by acoustic sensors -- SAW and QCM -- and a reflectometric sensor system based on optical fiber for purposes of chemical detection of volatile organic compound (VOCs), at room temperature. The carbon nanotubes have been deposited by the molecular engineering Langmuir-Blodgett (L-B) technique onto a buffer multilayer of cadmium arachidate prepared monolayer-by-monolayer using the L-B technique as well. The sensing multilayered material has been prepared both onto a standard silica optical fiber configured in a reflectometer sensor system and onto acoustic sensors -- SAW and QCM -- configured as oscillators. The acoustic sensors and the optical sensor have been exposed simultaneously, in the same test chamber, towards different VOCs such as ethanol, methanol, iso-propanol, acetone, ethylacetate, toluene with different vapor pressures for comparing the sensitivity of the coating onto the different kinds of acoustic and optical transducers. Moreover, for the same type of transducer, acoustic or optical, the effect of carbon nanotubes onto the gas sensitivity is remarkably higher in all investigated cases.

Cusano, A.; Cutolo, Antonello; Penza, M.; Cassano, G.; Aversa, P.; Antolini, F.; Giordano, Michele

2004-06-01

195

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

196

Longitudinally Graded Optical Fibers  

Science.gov (United States)

Described herein, for the first time to the best of our knowledge, are optical fibers possessing significant compositional gradations along their length due to longitudinal control of the core glass composition. More specifically, MCVD-derived germanosilicate fibers were fabricated that exhibited a gradient of up to about 0.55 weight percent GeO2 per meter. These gradients are about 1900 times greater than previously reported for fibers possessing longitudinal changes in composition. The refractive index difference is shown to change by about 0.001, representing a numerical aperture change of about 10%, over a fiber length of less than 20 m. The lowest attenuation measured from the present longitudinally-graded fiber (LGF) was 82 dB/km at a wavelength of 1550 nm, though this is shown to result from extrinsic process-induced factors and could be reduced with further optimization. The stimulated Brillouin scattering (SBS) spectrum from the LGF exhibited a 4.4 dB increase in the spectral width, and thus reduction in Brillouin gain, relative to a standard commercial single mode fiber, over a fiber length of only 17 m. Fibers with longitudinally uniform (i.e., not gradient) refractive index profiles but differing chemical compositions among various core layers were also fabricated to determine acoustic effects of the core slug method. The refractive index of the resulting preform varies by about +/- 0.00013 from the average. Upon core drilling, it was found that the core slugs had been drilled off-center from the parent preform, resulting in semi-circular core cross sections that were unable to guide light. As a result, optical analysis could not be conducted. Chemical composition data was obtained, however, and is described herein. A third fiber produced was actively doped with ytterbium (Yb3 ) and fabricated similarly to the previous fibers. The preforms were doped via the solution doping method with a solution of 0.015 M Yb 3 derived from ytterbium chloride hexahydrate and 0.30 M Al 3 derived from aluminum chloride hexahydrate. The doped preform was engineered to have two core layers of differing chemical composition, resulting in both a gradient refractive index profile as well as a gradient acoustic profile. While exhibiting higher loss than the original LGF, the Yb 3-doped fiber showed slightly better SBS suppression with preliminary calculations showing at least 6 dB reduction in Brillouin gain. Lastly, reported here is a straight-forward and flexible method to fabricate silica optical fibers of circular cladding cross-section and rectilinear cores whose aspect ratio and refractive index profile changes with position along the fiber in a deterministic way. Specifically, a modification to the process developed to produce longitudinally-graded optical fibers, was employed. Herein reported are MCVD-derived germanosilicate fibers with rectangular cores where the aspect ratio changes by nearly 200 % and the average refractive index changed by about 5 %. Fiber losses were measured to be about 50 dB/km. Such rectangular core fibers are useful for a variety of telecommunication and biomedical applications and the dimensional and optical chirp provides a deterministic way to control further the modal properties of the fiber. Possible applications of longitudinally graded optical fibers and future improvements are also discussed. The methods employed are very straight-forward and technically simple, providing for a wide variety of longitudinal refractive index and acoustic velocity profiles, as well as core shapes, that could be especially valuable for SBS suppression in high energy laser systems. Next generation analogs, with longitudinally-graded compositional profiles that are very reasonable to fabricate, are shown computationally to be more effective at suppressing SBS than present alternatives, such as externally-applied temperature or strain gradients.

Evert, Alexander George

197

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

Science.gov (United States)

Silica and silica incorporated nanocomposite materials have been extensively studied for a wide range of applications. Here we demonstrate an intriguing optical effect of silica that, depending on the solution pH, amplifies or attenuates the optical absorption of a variety of embedded optically active materials with very distinct properties, such as plasmonic Au nanoparticles, non-plasmonic Pt nanoparticles, and the organic dye rhodamine B (not a pH indicator), coated on an optical fiber. Interestingly, the observed optical response to varying pH appears to follow the surface charge density of the silica matrix for all the three different optically active materials. To the best of our knowledge, this optical effect has not been previously reported and it appears universal in that it is likely that any optically active material can be incorporated into the silica matrix to respond to solution pH or surface charge density variations. A direct application of this effect is for optical pH sensing which has very attractive features that can enable minimally invasive, remote, real time and continuous distributed pH monitoring. Particularly, as demonstrated here, using highly stable metal nanoparticles embedded in an inorganic silica matrix can significantly improve the capability of pH sensing in extremely harsh environments which is of increasing importance for applications in unconventional oil and gas resource recovery, carbon sequestration, water quality monitoring, etc. Our approach opens a pathway towards possible future development of robust optical pH sensors for the most demanding environmental conditions. The newly discovered optical effect of silica also offers the potential for control of the optical properties of optically active materials for a range of other potential applications such as electrochromic devices. PMID:25572664

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

2015-01-28

198

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

International Nuclear Information System (INIS)

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

199

Fiber optic gas sensor  

Science.gov (United States)

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

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

2010-01-01

200

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

 
 
 
 
201

Fluoride glass fiber optics  

CERN Document Server

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

Aggarwal, Ishwar D

1991-01-01

202

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

203

Optical fiber communications  

CERN Document Server

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

Keiser, Gerd

2008-01-01

204

Developments in distributed optical fiber detection technology  

Science.gov (United States)

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

Ye, Wei; Zhu, Qianxia; You, Tianrong

2014-12-01

205

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 NaYF4: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 103 W cm-2 to 106 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.

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

2012-11-01

206

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

207

Advanced Pulse Coding Techniques for Distributed Optical Fiber Sensors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Advanced optical pulse coding methods to enhance the performance of distributed optical fiber sensors are reviewed. In particular, the latest implementations dedicated to high-performance long-range Raman and Brillouin based distributed sensing are described.

Soto, Marcelo A.; The?venaz, Luc

2013-01-01

208

Fiber optic hydrogen sensors: a review  

Science.gov (United States)

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

Yang, Minghong; Dai, Jixiang

2014-12-01

209

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)

210

Introduction to optical fiber sensors  

International Nuclear Information System (INIS)

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

211

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

212

Advances on Optical Fiber Sensors  

Directory of Open Access Journals (Sweden)

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

Luciano Mescia

2013-12-01

213

Advances on Optical Fiber Sensors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Luciano Mescia; Francesco Prudenzano

2013-01-01

214

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)

215

Multichannel fiber optic laser vibrometer  

Science.gov (United States)

A non-contact nine channel fiber optic laser vibrometer has been developed to measure the vibrations of low mass flexible space structures. The Multi-Channel Fiber optic VIBrometer (MCFVIB) system is based on a commercial single channel laser vibrometer and a fiber-optic distribution system. This entailed the development of appropriate systems architecture for the optical signals, active 1 X 9 optical switch, and optical sensor heads suitable for coupling the reflected test signal back into the fiber optic system. MCFVIB employs single-mode, polarization maintaining fibers to maintain the signal coherence. The performance of the MCFVIB was tested at various vibrational frequencies using a shaker. Correlation of the measurements against those measured by an accelerometer indicate excellent linearity and accuracy for the fiber optic vibrometer system.

Changkakoti, Rupak; Kruzelecky, Roman V.; Ghosh, Asoke K.; Zheng, Wanping

1998-09-01

216

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

217

Optical Fiber Spectroscopy  

Science.gov (United States)

This is the final report of work done on NASA Grant NAG-1-443. The work covers the period from July 1, 1992 to December 1, 1998. During this period several distinct but related research studies and work tasks were undertaken. These different subjects are enumerated below with a description of the work done on each of them. The focus of the research was the development of optical fibers for use as distributed temperature and stress sensors. The initial concept was to utilize the utilize the temperature and stress dependence of emission from rare earth and transition metal ions substitutionally doped into crystalline or glass fibers. During the course of investigating this it became clear that fiber Bragg gratings provided a alternative for making the desired measurements and there was a shift of research focus on to include the photo-refractive properties of germano-silicate glasses used for most gratings and to the possibility of developing fiber laser sources for an integrated optical sensor in the research effort. During the course of this work several students from Christopher Newport University and other universities participated in this effort. Their names are listed below. Their participation was an important part of their education.

Buoncristiani, A. M.

1999-01-01

218

Fiber Optic Testing Course  

Science.gov (United States)

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

219

Optical fiber laser  

Energy Technology Data Exchange (ETDEWEB)

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

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

1987-07-14

220

In situ sensing of volatile organic compounds in groundwater: first field tests of a mid-infrared fiber-optic sensing system.  

Science.gov (United States)

A prototype mid-infrared sensor system for the determination of volatile organic pollutants in groundwater was developed and tested under real-world conditions. The sensor comprises a portable Fourier transform infrared spectrometer, coupled to the sensor head via mid-infrared transparent silver halide fiber-optic cables. A 10 cm unclad middle section of the 6-m-long fiber is coated with ethylene propylene copolymer in order to enrich the analytes within the penetration depth of the evanescent field protruding from the fiber sensor head. A mixture of tetrachloroethylene, dichlorobenzene, diethyl phthalate, and xylene isomers at concentrations in the low ppm region was investigated qualitatively and quantitatively in an artificial aquifer system filled with Munich gravel. This simulated real-world site at a pilot scale enables in situ studies of the sensor response and spreading of the pollutants injected into the system with controlled groundwater flow. The sensor head was immersed into a monitoring well of the aquifer system at a distance of 1 m downstream of the sample inlet and at a depth of 30 cm. Within one hour, the analytes were clearly identified in the fingerprint region of the IR spectrum (1300 to 700 cm(-1)). The results have been validated by head-space gas chromatography, using samples collected during the field measurement. Five out of six analytes could be discriminated simultaneously; for two of the analytes the quantitative results are in agreement with the reference analysis. PMID:14658691

Steiner, H; Jakusch, M; Kraft, M; Karlowatz, M; Baumann, T; Niessner, R; Konz, W; Brandenburg, A; Michel, K; Boussard-Plédel, C; Bureau, B; Lucas, J; Reichlin, Y; Katzir, A; Fleischmann, N; Staubmann, K; Allabashi, R; Bayona, J M; Mizaikoff, B

2003-06-01

 
 
 
 
221

Optical fiber synaptic sensor  

Science.gov (United States)

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

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

2011-06-01

222

Chemical Sensing Using Fiber Cavity Ring-Down Spectroscopy  

Directory of Open Access Journals (Sweden)

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

Hans-Peter Loock

2010-03-01

223

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

224

The bright future of optical fibers beyond telecommunications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nowadays optical fibers have become an integral part of life in the information age. Anyway, there are a lots of non-telecom applications for fibers, too, for example in high power generation and beam delivery for high precision applications such as the scribing of the solar cells, sensing and other fields of the physics and engineering. Researchers and engineers are still working hard to develop new optical fibers, which could outperform conventional fibers in specific fiel...

Passaro, Davide

2010-01-01

225

Fiber-optic seismic sensor  

International Nuclear Information System (INIS)

A vibration sensor is constructed by providing two preferably matched coils of fiber-optic material. When the sensor experiences vibration, a differential pressure is exerted on the two fiber coils. The differential pressure results in a variation in the relative optical path lengths between the two fibers so that light beams transmitted through the two fibers are differently delayed, the phase difference therebetween being a detectable indication of the vibration applied to the sensor

226

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

International Nuclear Information System (INIS)

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

227

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

2007-04-01

228

Optical fiber network : Cisco part  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Chen, Lu

2014-01-01

229

Anisotropic Metamaterial Optical Fibers  

CERN Document Server

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

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

2014-01-01

230

Optical Fiber Sensors for Smart Structures : A Review  

Directory of Open Access Journals (Sweden)

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

P. Kundu

2013-04-01

231

A phase mask fiber grating and sensing applications  

Directory of Open Access Journals (Sweden)

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

Preecha P. Yupapin

2003-09-01

232

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

233

A novel optical-fiber based surface plasmon resonance sensing architecture and its application to gastric cancer diagnostics  

Science.gov (United States)

The management of threats such as pandemics and explosives, and of health and the environment requires the rapid deployment of highly sensitive detection tools. Sensors based on Surface Plasmon Resonance (SPR) allow rapid, labelfree, highly sensitive detection, and indeed this phenomenon underpins the only label-free optical biosensing technology that is available commercially. In these sensors, the existence of surface plasmons is inferred indirectly from absorption features that correspond to the coupling of light to the surface plasmon. Although SPR is not intrinsically a radiative process, under certain conditions the surface plasmon can itself couple to the local photon states, and emit light. Here we show for the first time that by collecting and characterising this re-emitted light, it is possible to realise new SPR sensing architectures that are more compact, versatile and robust than existing approaches. It is applicable to a range of SPR geometries, including optical fibres. As an example, this approach has been used to demonstrate the detection of a protein identified as a being a biomarker for cancer.

Francois, Alexandre; Boehm, Jonathan; Penno, Megan; Hoffmann, Peter; Monro, Tanya M.

2011-05-01

234

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

Science.gov (United States)

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

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

2014-10-01

235

Fiber optic control system integration  

Science.gov (United States)

A total fiber optic, integrated propulsion/flight control system concept for advanced fighter aircraft is presented. Fiber optic technology pertaining to this system is identified and evaluated for application readiness. A fiber optic sensor vendor survey was completed, and the results are reported. The advantages of centralized/direct architecture are reviewed, and the concept of the protocol branch is explained. Preliminary protocol branch selections are made based on the F-18/F404 application. Concepts for new optical tools are described. Development plans for the optical technology and the described system are included.

Poppel, G. L.; Glasheen, W. M.; Russell, J. C.

1987-02-01

236

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

Science.gov (United States)

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

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

2014-09-01

237

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

238

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

239

Tackling the Limits of Optical Fiber Links  

CERN Document Server

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

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

2014-01-01

240

Fiber optic combiner and duplicator  

Science.gov (United States)

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

1979-01-01

 
 
 
 
241

Fiber optic acoustic sensor technology  

Science.gov (United States)

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

Cole, James; Kirkendall, Clay; Dandridge, Anthony

2005-04-01

242

Simultaneous single-fiber communications and linear position sensing  

Science.gov (United States)

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

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

1992-02-01

243

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

Directory of Open Access Journals (Sweden)

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

Mustapha Remouche

2013-06-01

244

chalcogenide microstructured optical fiber  

Science.gov (United States)

We demonstrate the supercontinuum (SC) generation in a four-hole As2S5 chalcogenide microstructured optical fiber (MOF) experimentally. The As2S5 glass has better property of transmission than As2S3 glass in the visible range. The four-hole As2S5 MOF is fabricated by a rod-in-tube method. The SCs generated by different pump wavelengths at 2,000, 2,300 and 2,500 nm in the MOF whose length is from 2.3 to 20 cm are demonstrated. Those pump wavelengths correspond to the chromatic dispersion wavelength in the normal chromatic dispersion region, the anomalous chromatic dispersion region close to zero-dispersion wavelength (ZDW) and the anomalous chromatic dispersion region far from ZDW, respectively. Wider SCs can be obtained when pumped at a wavelength in the anomalous dispersion region close to ZDW. The widest SC range of 4,280 nm (from 1,370 to 5,650 nm) covering two octaves was obtained in a 4.8-cm-long fiber pumped at 2,300 nm.

Gao, Weiqing; Duan, Zhongchao; Asano, Koji; Cheng, Tonglei; Deng, Dinghuan; Matsumoto, Morio; Misumi, Takashi; Suzuki, Takenobu; Ohishi, Yasutake

2014-09-01

245

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

246

Optical fiber dispersion characterization study  

Science.gov (United States)

The theory, design, and results of optical fiber pulse dispersion measurements are considered. Both the hardware and software required to perform this type of measurement are described. Hardware includes a thermoelectrically cooled injection laser diode source, an 800 GHz gain bandwidth produce avalanche photodiode and an input mode scrambler. Software for a HP 9825 computer includes fast Fourier transform, inverse Fourier transform, and optimal compensation deconvolution. Test set construction details are also included. Test results include data collected on a 1 Km fiber, a 4 Km fiber, a fused spliced, eight 600 meter length fibers concatenated to form 4.8 Km, and up to nine optical connectors.

Geeslin, A.; Arriad, A.; Riad, S. M.; Padgett, M. E.

1979-01-01

247

Fiber optic pressure sensors for nuclear power plants  

International Nuclear Information System (INIS)

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

248

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

International Nuclear Information System (INIS)

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

249

Classification of Fiber Optical Sensors  

Directory of Open Access Journals (Sweden)

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

Shivang Ghetia

2013-07-01

250

Shaping of Looped Miniaturized Chalcogenide Fiber Sensing Heads for Mid-Infrared Sensing  

Directory of Open Access Journals (Sweden)

Full Text Available Chalcogenide glass fibers are promising photonic tools to develop Fiber Evanescent Wave Spectroscopy (FEWS optical sensors working in the mid-infrared region. Numerous pioneering works have already been carried out showing their efficiency, especially for bio-medical applications. Nevertheless, this technology remains confined to academic studies at the laboratory scale because chalcogenide glass fibers are difficult to shape to produce reliable, sensitive and compact sensors. In this paper, a new method for designing and fabricating a compact and robust sensing head with a selenide glass fiber is described. Compact looped sensing heads with diameter equal to 2 mm were thus shaped. This represents an outstanding achievement considering the brittleness of such uncoated fibers. FEWS experiments were implemented using alcoholic solutions as target samples showing that the sensitivity is higher than with the routinely used classical fiber. It is also shown that the best compromise in term of sensitivity is to fabricate a sensing head including two full loops. From a mechanical point of view, the breaking loads of the loop shaped head are also much higher than with classical fiber. Finally, this achievement paves the way for the use of mid-infrared technology during in situ and even in vivo medical operations. Indeed, is is now possible to slide a chalcogenide glass fiber in the operating channel of a standard 2.8 mm diameter catheter.

Patrick Houizot

2014-09-01

251

Surface plasmon resonance based fiber optic refractive index sensors  

Science.gov (United States)

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

Hlubina, Petr; Kadulova, Miroslava; Ciprian, Dalibor

2014-12-01

252

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Allsop, T.; Bhamber, R.; Lloyd, G.; Miller, M. R.; Dixon, A.; Webb, D.; Ania Castan?o?n, Juan Diego; Bennion, I.

2012-01-01

253

Efficient fiber-optical interface for nanophotonic devices  

CERN Document Server

We demonstrate a method for efficient coupling of guided light from a single mode optical fiber to nanophotonic devices. Our approach makes use of single-sided conical tapered optical fibers that are evanescently coupled over the last ~10 um to a nanophotonic waveguide. By means of adiabatic mode transfer using a properly chosen taper, single-mode fiber-waveguide coupling efficiencies as high as 97(1)% are achieved. Efficient coupling is obtained for a wide range of device geometries which are either singly-clamped on a chip or attached to the fiber, demonstrating a promising approach for integrated nanophotonic circuits, quantum optical and nanoscale sensing applications.

Tiecke, T G; Thompson, J D; Peyronel, T; de Leon, N P; Vuleti?, V; Lukin, M D

2014-01-01

254

Broadband fiber optical parametric amplifiers.  

Science.gov (United States)

The bandwidth of a single-pump fiber optical parametric amplifier is governed by the even orders of fiber dispersion at the pump wavelength. The amplifier can exhibit gain over a wide wavelength range when operated near the fiber's zero-dispersion wavelength. It can also be used for broadband wavelength conversion,with gain. We have experimentally obtained gain of 10-18 dB as the signal wavelength was tuned over a 35-nm bandwidth near 1560 nm. PMID:19876087

Marhic, M E; Kagi, N; Chiang, T K; Kazovsky, L G

1996-04-15

255

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

256

Optimize Etching Based Single Mode Fiber Optic Temperature Sensor  

Directory of Open Access Journals (Sweden)

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

Ajay Kumar

2014-02-01

257

Sensing via optical interference  

Directory of Open Access Journals (Sweden)

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

Ryan C. Bailey

2005-04-01

258

Spatial coherence in optical fibers  

International Nuclear Information System (INIS)

The spatial degree of coherence on the cross-section of a graded-index optical fiber is evaluated under the assumption that all the propagating modes are uncorrelated among themselves. A detailed example for the case of parabolic fibers is given. (orig.)

259

Fiber optic refractive index monitor  

Science.gov (United States)

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

Weiss, Jonathan David (Albuquerque, NM)

2002-01-01

260

Fiber optics installer (FOI) certification exam guide  

CERN Document Server

Pass the FOI exam with a strong foundation in fiber optic technology Fiber Optics Installer (FOI) Certification Exam Guide gives you a solid foundation in fiber optics and thorough preparation for the Fiber Optics Installer (FOI) certification. Endorsed by the Electronics Technicians Association, International, this guide serves as both a comprehensive self-study course and a useful desk reference for aspiring fiber optics installers. Coverage includes the basic principles of light, optical fiber construction, safety, fusion, mechanical splicing, connectors, fiber-optic light sources, transmit

Woodward, Bill

2014-01-01

 
 
 
 
261

Scintillator fiber optic long counter  

Science.gov (United States)

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

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

1994-01-01

262

Innovative Plastic Optical Fiber Sensors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis describes the development of new types of fiber optic sensors for the measurement of mechanical quantities such as displacement, vibration and acceleration. Also, it describes the realization of specific acquisition systems designed to interrogate the developed sensors. Since optical fibers have been historically associated with high speed telecommunication links because of their very large bandwidth and low attenuation, there is a great interest for their employment in sensor app...

Casalicchio, Maria Luisa

2012-01-01

263

Classification of Fiber Optical Sensors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Shivang Ghetia; Ruchi Gajjar; Pujal Trivedi

2013-01-01

264

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

265

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

266

Localized wave solutions in optical fiber waveguides  

Energy Technology Data Exchange (ETDEWEB)

A novel bidirectional decomposition of exact solutions to the scalar wave equation has been shown to form a natural basis for synthesizing localized wave (LW) solutions that describe localized, slowly decaying transmission of energy in free space. In this work, we demonstrate the existence of LW solutions in optical fiber waveguides operated in the linear regime. In this sense, these solutions are fundamentally different from the non-linear, soliton-based communication systems. Despite the dielectric waveguiding constraints introduced by the fiber, solutions that resemble the fire-space solutions can be obtained with broad bandwidth source spectra As with the fire-space case, these optical waveguide LW solutions propagate over very long distances, undergoing only local variations. Four different source modulation spectra that give rise to solutions similar to Focus Wave Modes (FWM's), splash pulses, the scalar equivalent of Hilhon's spinor modes and the Modified Power Spectrum (MPS) pulses are considered. A detailed study of the MPS pulse is performed, practical issues regarding source spectra are addressed, and distances over which such LW solutions maintain their non-decaying nature are quantified. Present day state-of-the-art technology is not capable of meeting requirements that will make practical implementation of LW solution-based fiber optic systems a reality. We address futuristic technology issues and briefly describe efforts that could lead to efficient LW solution-based fiber optic systems.

Besieris, I.M.; Vengsarkar, A.M. (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Electrical Engineering)

1991-08-01

267

Localized wave solutions in optical fiber waveguides  

Energy Technology Data Exchange (ETDEWEB)

A novel bidirectional decomposition of exact solutions to the scalar wave equation has been shown to form a natural basis for synthesizing localized wave (LW) solutions that describe localized, slowly decaying transmission of energy in free space. In this work, we demonstrate the existence of LW solutions in optical fiber waveguides operated in the linear regime. In this sense, these solutions are fundamentally different from the non-linear, soliton-based communication systems. Despite the dielectric waveguiding constraints introduced by the fiber, solutions that resemble the fire-space solutions can be obtained with broad bandwidth source spectra As with the fire-space case, these optical waveguide LW solutions propagate over very long distances, undergoing only local variations. Four different source modulation spectra that give rise to solutions similar to Focus Wave Modes (FWM`s), splash pulses, the scalar equivalent of Hilhon`s spinor modes and the Modified Power Spectrum (MPS) pulses are considered. A detailed study of the MPS pulse is performed, practical issues regarding source spectra are addressed, and distances over which such LW solutions maintain their non-decaying nature are quantified. Present day state-of-the-art technology is not capable of meeting requirements that will make practical implementation of LW solution-based fiber optic systems a reality. We address futuristic technology issues and briefly describe efforts that could lead to efficient LW solution-based fiber optic systems.

Besieris, I.M.; Vengsarkar, A.M. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Electrical Engineering

1991-08-01

268

Monolithic fiber optic sensor assembly  

Energy Technology Data Exchange (ETDEWEB)

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

Sanders, Scott

2015-02-10

269

FBG sensor interrogation using fiber optical bistability in frequency domain  

Science.gov (United States)

In this paper, we propose a novel scheme of fiber Bragg grating interrogation by use of hybrid fiber optical bistable device (OBD). The OBD is realized in the fiber Bragg grating (FBG) sensing element. Light source is an electronic tuned widely swept ring fiber laser. In this experiment, FBG's are acting as optical intensity modulator and sensing elements at same time. Combined with feedback control circuit, the OBD can be used as an optic-fiber sensor working in digital type through bistable switching phenomenon. We discuss the mechanism of this bistable sensor. Scanning the bias Voltage on PZT, the bistable pulse signal can be counted by circuit that operates in the manner of a pulse-equivalent. If we use 16 bit Digital Analog Converter (DAC), the resolution will achieve 1pm level. High accuracy, high speed and high ratio of signal to noise are the advantages of this scheme.

Lv, Guohui; Ou, Jinping; Ye, Hongan; Zhou, Zhi; Shang, Shaohua; Yang, Chao; Wang, Huiying

2007-01-01

270

Te-based glass fiber for far-infrared biochemical sensing up to 16 ?m.  

Science.gov (United States)

Chalcogenide glass fibers are very suitable to carry out mid-infrared spectroscopy by Fiber Evanescent Wave Spectroscopy (FEWS). Nowadays, selenide glasses are used for FEWS, but the reachable domain is limited in the infrared to typically 12 µm. Te-rich glasses, due to their heavy atomic weight, are better for far-infrared sensing but they crystallize easily and until now that was difficult to prepare operational optical fibers from such glasses. In this work, Te-Ge-AgI highly purified glasses have been prepared and successfully drawn into optical fiber. The minimum of attenuation is 3 dB/m around 10 ?m, which is up to now the lowest value ever measured for Te-based fiber. Overall, such fibers open the sensing window up to 16 ?m against 12 µm so far. Then, for the first time, tapered telluride fibers with different diameters at the sensing zone were obtained during the fiber drawing process. Chloroform and butter were used to test the fiber infrared sensing ability, and the sensitivity has been greatly enhanced as the sensing zone fiber diameter decreases. Finally, the new protocol of telluride glass preparation allows shaping them into efficient functional fibers, opening further in the mid-infrared which is essential for chemical spectroscopy. PMID:25321505

Cui, Shuo; Boussard-Plédel, Catherine; Lucas, Jacques; Bureau, Bruno

2014-09-01

271

Wavelength demodulation of fiber grating sensors using hybrid optical bistability  

Science.gov (United States)

In this article, a novel approach for demodulation of fiber grating sensors with high resolution is proposed based on a hybrid fiber optical bistablity device (OBD). This OBD is consisted of a FFP ring-cavity laser, fiber Bragg grating (FBG) and a certain optoelectronic feedback circuit. The optical bistability can be realized through alternative the center wavelength of the tunable fiber laser when the output power of the laser is fixed. The Bragg wavelength of sensing grating is determined by the switching on voltage of OBD.

Lv, Guohui; Ou, Jinping; Wang, Huiying; Jiang, Xu; Shang, Shaohua

2007-07-01

272

Porous plastic optical fiber sensor for ammonia measurement.  

Science.gov (United States)

A porous plastic optical fiber has been developed for use in chemical gas sensing. This porous plastic waveguide, which was made with copolymer materials, has an interconnective porous structure as well as uniformity of pore size. These sensors are based on in-line optical absorption within the porous plastic fiber core and have much greater sensitivities than sensors based on evanescent coupling to a surrounding medium. Furthermore, this fiber simultaneously exhibits very high gas permeability and liquid impermeability. This combination makes the fiber particularly suitable for gas concentration measurements in aqueous samples. An ammonia gas sensor has been tested to demonstrate the effectiveness of this porous plastic waveguide. PMID:20555459

Zhou, Q; Kritz, D; Bonnell, L; Sigel, G H

1989-06-01

273

A fiber-optic current sensor for aerospace applications  

International Nuclear Information System (INIS)

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

274

Antiguiding in microstructured optical fibers.  

Science.gov (United States)

Antiguiding, as opposed to positive index-contrast guiding (or index-guiding), in microstructured air-silica optical fibers is shown to have a significant influence on the fiber's transmission property, especially when perturbations exist near the defect core. Antiguided modes are numerically analyzed in such fibers by treating the finite periodic air-silica composite (including the central defect) as the core and outer bulk silica region as the cladding. Higher-order modes, which can couple energy from the fundamental mode in the presence of waveguide irregularities, are predicted to be responsible for high leakage loss of realistic holey fibers. The modal property of an equivalent simple step-index antiguide model is also analyzed. Results show that approximation from a composite core waveguide to a simple step-index fiber always neglects some important modal characteristics. PMID:19471516

Yan, M; Shum, P

2004-01-12

275

Multimode optical fiber based spectrometers  

CERN Document Server

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

Redding, Brandon; Cao, Hui

2013-01-01

276

Installation and testing of high-temperature optical fiber sensors  

Science.gov (United States)

We report test results using optical fiber sensor to measure dynamic strain and temperature on ceramic-matrix composite (CMC) specimens at temperatures up to 600 degrees C. For strain sensing we are employing extrinsic Fabry-Perot interferometric strain gages fabricated with gold-coated optical fibers and attached to the CMC specimens using high- temperature ceramic adhesive. For temperature measurements, specially fabricated Bragg and long-period grating sensors are being employed.

Greene, Jonathan A.; Wavering, Thomas A.; Bailey, Timothy A.; Kozikowski, Carrie L.; Poland, Stephen H.; Gunther, Michael F.; Murphy, Kent A.; Camden, Michael P.; Simmons, Larry W.

1998-07-01

277

Fiber-optic strain-displacement sensor employing nonlinear buckling.  

Science.gov (United States)

A new class of intrinsic fiber-optic strain-displacement sensors based on the precisely controlled nonlinear buckling of optical fibers and the resulting optical bend loss is introduced. A multimode fiber version of the sensor is described that exhibits a sensing range convenient for many structural monitoring applications (<100 nm to several millimeters), linear response over a wide range of displacements, and excellent repeatability. It is extremely simple to fabricate and employs inexpensive optoelectronics. A high-temperature version of the sensor is capable of operation at temperatures as high as 600 degrees C. PMID:18253297

Voss, K F; Wanser, K H

1997-05-01

278

Scintillating optical fiber trajectory detectors  

International Nuclear Information System (INIS)

Measurements of attenuation in several types of plastic scintillating optical fibers give attenuation lengths varying from 0.8 to 1.5 m. By comparing attenuation as a function of wavelength in fibers of different thicknesses we infer the contributions to the attenuation from reflection losses and bulk scintillation losses. We find good agreement between these values and calculated estimates of attenuation in scintillator. We have also calculated the effective scintillation efficiency of small fibers relative to that of bulk scintillator (for scintillator with dimethyl POPOP as the waveshifting dye) for the two cases of optically coupled and decoupled fibers. Scintillating fiber ribbons made of 200 ?m square cross section fibers were exposed to relativistic iron nuclei at the LBL Bevalac, and positional resolution of 70 ?m was obtained. Relativistic neon and carbon were also detected in these ribbons. In a similar exposure of 100 ?m fibers to 50 MeV/n nitrogen nuclei at the NSCL cyclotron, Michigan State University, a positional resolution of about 50 ?m was obtained. (orig.)

279

Thermally regenerated fiber Bragg gratings in twin-air-hole microstructured fibers for high temperature pressure sensing  

Science.gov (United States)

We present thermally regnenerated fiber Bragg grating in air-hole microstructured fibers for high temperature hydrostatic pressure sensing application. Saturated type I gratings were inscribed in hydrogen-loaded two-hole optical fibers using 248-nm KrF laser, and regenerated during annealing at 800ºC. The fiber Bragg grating resonance wavelength shift and peak splits were studied as a function of external hydrostatic pressure from 15 psi to 2400 psi. The grating pressure sensor shows stable and reproducible operation up to 800ºC. This paper demonstrates a multiplexible pressure sensor network technology for high temperature harsh environment using a single fiber feedthrough.

Chen, Tong; Chen, Rongzhang; Jewart, Charles; Zhang, Botao; Canning, John; Cook, Kevin; Chen, Kevin P.

2011-06-01

280

All-optical storage and processing in optical fibers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

The?venaz, Luc; Primerov, Nikolay; Chin, Sanghoon; Antman, Yair; Denisov, Andrey; Zadok, Avi; Santagiustina, Marco

2012-01-01

 
 
 
 
281

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

282

Fiber optics principles and practices  

CERN Document Server

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

Al-Azzawi, Abdul

2007-01-01

283

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...

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

2011-01-01

284

Refractive Index Measurement of Liquids Based on Microstructured Optical Fibers  

Directory of Open Access Journals (Sweden)

Full Text Available This review is focused on microstructured optical fiber sensors developed in recent years for liquid RI sensing. The review is divided into three parts: the first section introduces a general view of the most relevant refractometric sensors that have been reported over the last thirty years. Section 2 discusses several microstructured optical fiber designs, namely, suspended-core fiber, photonic crystal fiber, large-core air-clad photonic crystal fiber, and others. This part is also divided into two main groups: the interferometric-based and resonance-based configurations. The sensing methods rely either on full/selective filling of the microstructured fiber air holes with a liquid analyte or by simply immersing the sensing fiber into the liquid analyte. The sensitivities and resolutions are tabled at the end of this section followed by a brief discussion of the obtained results. The last section concludes with some remarks about the microstructured fiber-based configurations developed for RI sensing and their potential for future applications.

Susana Silva

2014-12-01

285

Fiber-optic currents measurements  

Energy Technology Data Exchange (ETDEWEB)

Polarization maintaining pigtailed laser diodes have greatly increased the ease with which fiber-optic sensors for Faraday current measurements on large pulsed experiments can be deployed. 670, 830, and 1300 nm units are readily available. Such diode lasers can easily be mounted in an RF shielded box along with the simple electronics and batteries to power them. Our units measure 16.5 {times} 8 {times} 6 cm. and have a single external control; an on off switch. They use two 1.5 volt ``C`` cell batteries. By using an LT1073 chip in the electronics the batteries are an energy source rather than a voltage source. These units can provide 100 mA drive to a LT015MD laser diode so that 1 mW of 830 nm fight exits the fiber pigtail for up to 23 hours with no detectable droop in power. For the sensor element twisted single mode low birefringence fibers are wrapped around the region of interest. The fiber pigtail is fused to the sensor section so changes in alignment are avoided. The light exiting the fiber sensor section is immediately analyzed by a compact, 3 {times} 3.5 {times} 5 cm, bulk optical unit which outputs quadrature optical signals into two multimode fibers leading to detectors in a screen room. The system is thus completely free of ground loops and is as immune to noise as the screen room. These sensors have the usual advantages claimed for them and the all dielectric feature was the original reason for their use on our experiments. The ease of deployment however is not usually cited. On our Pegasus II experiment the need arose for a total current measurement at the main header of the capacitor banks. A single turn of optical fiber was easily strung in a 6.4 m diameter circle and attached to laser and analyzer in a few hours.

Forman, P.R.; Looney, L.D.; Tabaka, L.J.

1993-03-01

286

Fiber-optic currents measurements  

Science.gov (United States)

Polarization maintaining pigtailed laser diodes have greatly increased the ease with which fiber-optic sensors for Faraday current measurements on large pulsed experiments can be deployed. 670, 830, and 1300 nm units are readily available. Such diode lasers can easily be mounted in an RF shielded box along with the simple electronics and batteries to power them. Our units measure 16.5 x 8 x 6 cm. and have a single external control; an on off switch. They use two 1.5 volt C cell batteries. By using an LT1073 chip in the electronics, the batteries are an energy source rather than a voltage source. These units can provide 100 mA drive to a LT015MD laser diode so that 1 mW of 830 nm light exits the fiber pigtail for up to 23 hours with no detectable droop in power. For the sensor element, twisted single mode low birefringence fibers are wrapped around the region of interest. The fiber pigtail is fused to the sensor section so changes in alignment are avoided. The light exiting the fiber sensor section is immediately analyzed by a compact, 3 x 3.5 x 5 cm, bulk optical unit which outputs quadrature optical signals into two multimode fibers leading to detectors in a screen room. The system is thus completely free of ground loops and is as immune to noise as the screen room. These sensors have the usual advantages claimed for them and the all dielectric feature was the original reason for their use on our experiments. The ease of deployment however is not usually cited. On our Pegasus 2 experiment, the need arose for a total current measurement at the main header of the capacitor banks. A single turn of optical fiber was easily strung in a 6.4 m diameter circle and attached to laser and analyzer in a few hours.

Forman, P. R.; Looney, L. D.; Tabaka, L. J.

287

Fiber-optic currents measurements  

Energy Technology Data Exchange (ETDEWEB)

Polarization maintaining pigtailed laser diodes have greatly increased the ease with which fiber-optic sensors for Faraday current measurements on large pulsed experiments can be deployed. 670, 830, and 1300 nm units are readily available. Such diode lasers can easily be mounted in an RF shielded box along with the simple electronics and batteries to power them. Our units measure 16.5 [times] 8 [times] 6 cm. and have a single external control; an on off switch. They use two 1.5 volt C'' cell batteries. By using an LT1073 chip in the electronics the batteries are an energy source rather than a voltage source. These units can provide 100 mA drive to a LT015MD laser diode so that 1 mW of 830 nm fight exits the fiber pigtail for up to 23 hours with no detectable droop in power. For the sensor element twisted single mode low birefringence fibers are wrapped around the region of interest. The fiber pigtail is fused to the sensor section so changes in alignment are avoided. The light exiting the fiber sensor section is immediately analyzed by a compact, 3 [times] 3.5 [times] 5 cm, bulk optical unit which outputs quadrature optical signals into two multimode fibers leading to detectors in a screen room. The system is thus completely free of ground loops and is as immune to noise as the screen room. These sensors have the usual advantages claimed for them and the all dielectric feature was the original reason for their use on our experiments. The ease of deployment however is not usually cited. On our Pegasus II experiment the need arose for a total current measurement at the main header of the capacitor banks. A single turn of optical fiber was easily strung in a 6.4 m diameter circle and attached to laser and analyzer in a few hours.

Forman, P.R.; Looney, L.D.; Tabaka, L.J.

1993-01-01

288

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

289

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)

290

Novel optical microresonators for sensing applications  

Science.gov (United States)

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

Wang, Hanzheng

291

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.

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

2013-01-01

292

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

293

The new-conceptual fiber-optic gyroscope  

Science.gov (United States)

A new-conceptual fiber-optic gyroscope is introduced. The gyroscope employs the two newly-emerged novel technologies: the optical frequency-modulated continuous-wave (FMCW) interference, and the differential fiber-optic gyroscope, and therefore, it can overcome the problems in the traditional fiber-optic gyroscopes, such as temperature drift and poor long-term stability. The FMCW interference, which was originally investigated in radar technology, has been successfully used to construct various fiber-optic interferometers and sensors. The advantages of this technology include accurate calibration of the phase, simple count of fringes, and easy signal processing. The interest in the application of the FMCW technique to rotation sensing has been growing for a long period. The problem in the FMCW fiber-optic gyroscope is that the gyroscope must be an unbalanced, and the initial optical path difference in the gyroscope will cause an unexpected non-reciprocal phase drift if the environmental conditions are unstable. This paper reports a differential FMCW fiber-optic gyroscope. The advantages of this fiber-optic gyroscope include: (1) Due to the nature of the differential interferometer structure, the unexpected non-reciprocal phase drift is automatically removed, and the calibration fact of the gyroscope is automatically doubled. (2) Benefited from the FMCW technology, this gyroscope has no zero-sensitivity point problem, and it has a higher resolution and a larger dynamic range.

Zheng, Gang

2010-11-01

294

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

DEFF Research Database (Denmark)

Polymer optical fibers (POFs) are ideal for applications as the sensing element in fiber-optical microphones and accelerometers based on fiber Bragg gratings (FBGs) due to their reduced Young’s Modulus of 3.2GPa, compared to 72GPa of Silica. To maximize the sensitivity and the dynamic range of the device the outer diameter and the length of the sensing fiber segment should be as small as possible. To this end we have fabricated 3mm FBGs in single-mode step-index POFs of diameter 115 micron, using 325nm UV writing and a phase-mask technique. 6mm POF sections with FBGs in the center have been glued to standard Silica SMF28 fibers. These POF FBGs have been characterized in terms of temperature and strain to find operating regimes with no hysteresis. Commercial fast wavelength interrogators (KHz) are shown to be able to track the thin POF FBGs and they are finally applied in a prototype accelerometer. The specs are compared to the specs obtained when using Silica FBGs.

Yuan, Scott Wu Technical University of Denmark,

2010-01-01

295

Optically powered fiber networks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2008-01-01

296

Laser and Fiber Optics Student Resources  

Science.gov (United States)

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

297

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

298

Sealed fiber-optic bundle feedthrough  

Science.gov (United States)

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

299

Optical fibers and RF a natural combination  

CERN Document Server

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

Romeiser, Malcolm

2004-01-01

300

Nonlinear fiber optics formerly quantum electronics  

CERN Document Server

The field of nonlinear fiber optics has grown substantially since the First Edition of Nonlinear Fiber Optics, published in 1989. Like the First Edition, this Second Edition is a comprehensive, tutorial, and up-to-date account of nonlinear optical phenomena in fiber optics. It synthesizes widely scattered research material and presents it in an accessible manner for students and researchers already engaged in or wishing to enter the field of nonlinear fiber optics. Particular attention is paid to the importance of nonlinear effects in the design of optical fiber communication systems. This is

Agrawal, Govind

1995-01-01

 
 
 
 
301

Overview of Fiber-Optical Sensors  

Science.gov (United States)

Design, development, and sensitivity of sensors using fiber optics reviewed. State-of-the-art and probable future developments of sensors using fiber optics described in report including references to work in field. Serves to update previously published surveys. Systems incorporating fiber-optic sensors used in medical diagnosis, navigation, robotics, sonar, power industry, and industrial controls.

Depaula, Ramon P.; Moore, Emery L.

1987-01-01

302

Chiral fiber gratings: perspectives and challenges for sensing applications  

Science.gov (United States)

Chiral fiber gratings are produced in a microforming process in which optical fibers with noncircular or nonconcentric cores are twisted as they pass though a miniature oven. Periodic glass structures as stable as the glass material itself are produced with helical pitch that ranges from under a micron to hundreds of microns. The geometry of the fiber cross section determines the symmetry of the resulting structure which in turn determines its polarization selectivity. Single helix structures are polarization insensitive while double helix gratings interact only with a single optical polarization. Both single and double helix gratings may act as a fiber long period grating, coupling the core and cladding modes. The coupling is manifested in a series of narrow dips in the transmission spectrum. The dip position is sensitive to fiber elongation, twist and temperature, and to the refractive index of the surrounding medium. The suitability of chiral gratings for sensing pressure, temperature and liquid levels is investigated. Polarization insensitive single helix silica glass gratings display excellent stability up to temperatures of 600°C, while a pressure sensor with dynamic range of nearly 40 dB is demonstrated in polarization selective double helix gratings.

Kopp, Victor I.; Churikov, Victor M.; Zhang, Guoyin; Singer, Jonathan; Draper, Christopher W.; Chao, Norman; Neugroschl, Daniel; Genack, Azriel Z.

2007-07-01

303

Optically powered fiber networks.  

Science.gov (United States)

Optically powered networks are demonstrated. Heterogeneous subscribers having widely varying needs with respect to power and band-width can be effectively controlled and optically supplied by a central of-fice. The success of the scheme relies both on power-efficient innovative hardware and on a novel low-energy medium access control protocol. We demonstrate a sensor network with subscribers consuming less than 1 microW average power, and an optically powered high-speed video link transmitting data at a bitrate of 100 Mbit/s. PMID:19104615

Röger, M; Böttger, G; Dreschmann, M; Klamouris, C; Huebner, M; Bett, A W; Becker, J; Freude, W; Leuthold, J

2008-12-22

304

Laser and Fiber Optics Curriculum Resources  

Science.gov (United States)

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

305

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

306

Gamma-rays and neutrons effects on optical fibers and Bragg gratings for temperature sensors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The nuclear industry shows an increasing interest in the fiber optic technology for both data communication and sensing applications in nuclear plants. The optical fibers offer several advantages and the sensors based on this technology do not need any electrical power at the sensing point, they have a quick response and they can be easily multiplexed: in the case of a temperature sensor, several thermocouples can be substituted by a single fiber, resulting in a decrease of the waste material...

Morana, Adriana

2013-01-01

307

Real-time In-Flight Strain and Deflection Monitoring with Fiber Optic Sensors  

Science.gov (United States)

This viewgraph presentation reviews Dryden's efforts to develop in-flight monitoring based on Fiber Optics. One of the motivating factors for this development was the breakup of the Helios aircraft. On Ikhana the use of fiber optics for wing shape sensing is being developed. They are being used to flight validate fiber optic sensor measurements and real-time wing shape sensing predictions on NASA's Ikhana vehicle; validate fiber optic mathematical models and design tools; Assess technical viability and, if applicable, develop methodology and approach to incorporate wing shape measurements within the vehicle flight control system, and develop and flight validate advanced approaches to perform active wing shape control.

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

2008-01-01

308

Active Optical Fibers Doped with Ceramic Nanocrystals  

Directory of Open Access Journals (Sweden)

Full Text Available Erbium-doped active optical fiber was successfully prepared by incorporation of ceramic nanocrystals inside a core of optical fiber. Modified chemical vapor deposition was combined with solution-doping approach to preparing preform. Instead of inorganic salts erbium-doped yttrium-aluminium garnet nanocrystals were used in the solution-doping process. Prepared preform was drawn into single-mode optical fiber with a numerical aperture 0.167. Optical and luminescence properties of the fiber were analyzed. Lasing ability of prepared fiber was proofed in a fiber-ring set-up. Optimal laser properties were achieved for a fiber length of 20~m. The slope efficiency of the fiber-laser was about 15%. Presented method can be simply extended to the deposition of other ceramic nanomaterials.

Jan Mrazek

2014-01-01

309

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

International Nuclear Information System (INIS)

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.

310

Use of optical fibers in spectrophotometry  

Science.gov (United States)

The use of single or small numbers of fiber optic fibers in astronomical spectroscopy with the goal of greater spectrophotometric and radial velocity accuracy is discussed. The properties of multimode step index fibers which are most important for this application are outlined, as are laboratory tests of currently available fibers.

Ramsey, Lawrence W.

1988-01-01

311

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

312

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

313

Fiber-optically sensorized composite wing  

Science.gov (United States)

Electromagnetic interference (EMI) immune and light-weight, fiber-optic sensor based Structural Health Monitoring (SHM) will find increasing application in aerospace structures ranging from aircraft wings to jet engine vanes. Intelligent Fiber Optic Systems Corporation (IFOS) has been developing multi-functional fiber Bragg grating (FBG) sensor systems including parallel processing FBG interrogators combined with advanced signal processing for SHM, structural state sensing and load monitoring applications. This paper reports work with Auburn University on embedding and testing FBG sensor arrays in a quarter scale model of a T38 composite wing. The wing was designed and manufactured using fabric reinforced polymer matrix composites. FBG sensors were embedded under the top layer of the composite. Their positions were chosen based on strain maps determined by finite element analysis. Static and dynamic testing confirmed expected response from the FBGs. The demonstrated technology has the potential to be further developed into an autonomous onboard system to perform load monitoring, SHM and Non-Destructive Evaluation (NDE) of composite aerospace structures (wings and rotorcraft blades). This platform technology could also be applied to flight testing of morphing and aero-elastic control surfaces.

Costa, Joannes M.; Black, Richard J.; Moslehi, Behzad; Oblea, Levy; Patel, Rona; Sotoudeh, Vahid; Abouzeida, Essam; Quinones, Vladimir; Gowayed, Yasser; Soobramaney, Paul; Flowers, George

2014-04-01

314

Fiber Fourier optics: previous publication  

Science.gov (United States)

Subsequent to publication of my recent Letter on fiber Fourier optics, I became aware that the basic physical concepts described in this Letter had already been described in an earlier Letter by Marhic, who discussed discrete Fourier transforms using single-mode star networks. I regret that, despite the best efforts of the referees and me, this earlier publication was overlooked, and I can only hope that renewed publication of the basic idea may stimulate further efforts toward its practical implementation.

Siegman, A. E.

2002-03-01

315

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

316

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

317

Applications of capillary optical fibers  

Science.gov (United States)

The paper updates and summarizes contemporary applications of capillary optical fibers. Some of these applications are straight consequence of the classical capillary properties and capillary devices like: rheometry, electrophoresis, column chromatography (gas and liquid). Some new applications are tightly connected with co-propagation (or counter-propagation) of micro-mass together with optical wave - evanescent or of considerable intensity. In the first case, the optical wave is propagated in a narrow (more and more frequently single-mode) optical ring core adjacent to the capillary hole. The optical propagation is purely refractive. In the second case, the intensity maximum of optical wave is on the capillary long axis, i.e. in the center of the hole. The optical propagation is purely photonic, i.e. in a Bragg waveguide (one dimensional photonic band-gap). The capillary hole is filled with vacuum or with propagated matter (gas, liquid, single atoms, continuous particle arrangement). Optical capillaries, filamentary and embedded, are turning to a fundamental component of nano- and micro-MOEMS.

Romaniuk, Ryszard

2006-10-01

318

Raman effect in optical fiber and liquid-core fiber  

Science.gov (United States)

The backscattering spectrum of optical fiber G652 (SiO2) has been researched, in the Stokes region the first order and second order Raman spectrum have been observed and the ZX band backscattering spectrum is first observed. The small signal pump on/off Raman gain spectrums have been measured by the 1427.2nm Raman laser and Q8384 optical spectrum analyzer, during different pump power. The Raman gain is 19dB and gain band width is 96nm (1440nm-1536nm) during the pump power is 700mw. The liquid-core optical fiber is made ofhollow quartz fiber filling organic liquid materials including C6H6, CS2, CCl4 and so on. The constitution and proportion of liquid materials are designed. Raman effect in liquid-core optical fiber is researched. The liquid-core optical fiber Raman amplifier are designed by using FRA optimum design software. This observed Stokes frequency shift is characteristic of the 992-cm-1, 656-cm-1, and 459cm-1 lines in C6H6 CS2, andCCl4. The Raman laser (1427mm) is used as pumping laser. A mini-ASE light source is used as signal source. The Raman spectrum has been measured by OSA Q8384 in liquid-core optical fiber. The Raman amplified bandwidth in liquid-core optical fiber is researched. The relations between the pumping threshold and liquid-core optical fiber length are attained.

Jin, Shangzhong; Zhou, Wen; Zhang, Zaixuan; Wang, Jianfeng; Liu, Honglin

2002-08-01

319

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2007-01-01

320

Interferometric closed-loop fiber-optic gyroscopes  

Science.gov (United States)

The operation of Fiber Optic Gyro is based on the Sagnac Effect which states that light beams propagating along opposite directions in a rotating frame experience an optical path length difference. These two counter-propagating waves propagate within a closed fiber coil, and when this coil rotates the resultant phase difference is proportional to the rotation rate ?. Fiber optic gyroscopes are desirable devices for many navigation and guidance applications because, being solid state devices, they have several major advantages including light weight, long working lifetimes, no moving parts and operate using low voltage power. In this paper the Optolink's single-axis and three-axis fiber optic gyroscopes are described. The Optolink's FOGs consist of the light-emitting diode, one or three photodetectors, circulators and polarization maintaining fiber couplers to divide the light into two or three parts, one or three sets of ring interferometers to sense one or three orthogonal angular rates, and installed PCB signal processing circuits. The ring interferometer consists of a multifunction integrated optic chip and polarization maintaining fiber coil, both these components are designed and fabricated by Optolink. The results illustrate the versatility of the technology, showing its potential to meet both the low-cost, compact sized needs of tactical guidance, as well as the very high performance needs of inertial navigation and precision applications. The optic and electronic blocks of closed-loop gyroscopes with integrated optic components are also considered in this paper.

Korkishko, Yuri N.; Fedorov, Vyacheslav &.; Prilutskii, Victor &.; Ponomarev, Vladimir G.; Morev, Ivan V.; Kostritskii, Sergey M.

2012-02-01

 
 
 
 
321

Simultaneous Temperature and Strain Sensing for Cryogenic Applications Using Dual-Wavelength Fiber Bragg Gratings  

Science.gov (United States)

A new technique has been developed for sensing both temperature and strain simultaneously by using dual-wavelength fiber-optic Bragg gratings. Two Bragg gratings with different wavelengths were inscribed at the same location in an optical fiber to form a sensor. By measuring the wavelength shifts that resulted from the fiber being subjected to different temperatures and strains, the wavelength-dependent thermo-optic coefficients and photoelastic coefficients of the fiber were determined. This enables the simultaneous measurement of temperature and strain. In this study, measurements were made over the temperature range from room temperature down to about 10 K, addressing much of the low temperature range of cryogenic tanks. A structure transition of the optical fiber during the temperature change was found. This transition caused splitting of the waveforms characterizing the Bragg gratings, and the determination of wavelength shifts was consequently complicated. The effectiveness and sensitivities of these measurements in different temperature ranges are also discussed.

Wu, Meng-Chou; Prosser, William H.

2003-01-01

322

Optical Fiber Grating based Sensors  

DEFF Research Database (Denmark)

In this thesis differenct optical fiber gratings are used for sensor purposes. If a fiber with a core concentricity error (CCE) is used, a directional dependent bend sensor can be produced. The CCE direction can be determined by means of diffraction. This makes it possible to produce long-period gratings in a fiber with a CCE direction parallel or perpendicular to the writing direction. The maximal bending sensitivity is independent on the writing direction, but the detailed bending response is different in the two cases. A temperature and strain sensor, based on a long-period grating and two sampled gratings, was produced and investigated. It is based on the different temperature and strain response of these gratings. Both a transfer matrix method and an overlap calculation is performed to explain the sensor response. Another type of sensor is based on tuning and modulation of a laser wavelength. It is shown that it is possible to tune and modulate a DFB fiber laser with both strain from a piezoelectric transducer and by temperature through resistive heating of a methal film. Both a chemical deposited silver layer and an electron-beam evaporation technique has been investigated, to find the most reproducible method. Such a laser can be applied for gas monitoring and it can be stabilized by locking it to an absorption line. The locked laser has a stability of ~2 MHz, which makes it suitable as a wavelength standard in the 1.5 um telecommunication band.

Michelsen, Susanne

2003-01-01

323

Fiber optic neutron imaging system: calibration  

International Nuclear Information System (INIS)

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

324

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

325

Optical Fiber Sensor Instrumentation for Slagging Coal Gasifiers  

Energy Technology Data Exchange (ETDEWEB)

Coal gasifier is one of the most promising solutions for clean fossil energy. Refractory thickness monitoring and online real-time temperature measurement is needed for improved reliability and advanced process control for current and future generation power plants. The objective of this program is to design and implement an optical fiber based sensing system that could potentially be used to monitor refractory wall thickness and temperature inside a coal gasifier. For the thickness monitoring, the system should be able to operate at temperatures up to 1000 C. For this temperature range, silica fiber can still work so it is chosen for the sensor design. The measurement is based on a photon counting optical time domain reflectometer. A narrow light pulse is launched into a silica fiber which could be embedded into the gasifier refractory wall, and is partially reflected by the far end of the fiber. The time of flight of the light pulse in the fiber then gives an indication of the position of the fiber end, which is a function of the wall thickness when the fiber is embedded. Results obtained show a measurement accuracy of {+-}2cm in environment of 1000 C with a saw cut fiber end. When the fiber end is corroded by sodium carbide at 900 C, the accuracy is {+-}3cm. For the temperature measurement, a single crystal sapphire fiber sensor is designed. The sapphire fiber guides the broadband light from a light emitting diode to a sapphire wafer functioning as a Fabry-Perot interferometer and the wafer optical thickness is a function of temperature. The returned optical signal is then demodulated by multimode fiber based whitelight interferometry. The system was tested up to 1500 C with a measurement accuracy of {+-}10 C for the entire measurement range.

Anbo Wang; Kristie Cooper

2008-07-19

326

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 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

327

Air backed mandrel type fiber optic hydrophone with low noise floor  

Science.gov (United States)

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

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

2014-10-01

328

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

Science.gov (United States)

The platform presented here was devised to address the unmet need for real time label-free in vivo sensing by bringing together a refractive index transduction mechanism based on Whispering Gallery Modes (WGM) in dye doped microspheres and Microstructured Optical Fibers. In addition to providing remote excitation and collection of the WGM signal, the fiber provides significant practical advantages such as an easy manipulation of the microresonator and the use of this sensor in a dip sensing architecture, alleviating the need for a complex microfluidic interface. Here, we present the first demonstration of the use of this approach for biological sensing and evaluate its limitation in a sensing configuration deprived of liquid flow which is most likely to occur in an in vivo setting. We also demonstrate the ability of this sensing platform to be operated above its lasing threshold, enabling enhanced device performance. PMID:25585104

François, Alexandre; Reynolds, Tess; Monro, Tanya M

2015-01-01

329

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

Directory of Open Access Journals (Sweden)

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

Alexandre François

2015-01-01

330

Fiber-optical accelerometers based on polymer optical fiber Bragg gratings  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fiber-optical accelerometers based on polymer optical fiber Bragg gratings (FBGs) are reported. We have written 3mm FBGs for 1550nm operation, characterized their temperature and strain response, and tested their performance in a prototype accelerometer.

Yuan, Scott Wu; Stefani, Alessio; Bang, Ole; Andresen, Søren; Nielsen, Finn Kryger; Jacobsen, Torben; Rose, Bjarke; Herholdt-rasmussen, Nicolai

2010-01-01

331

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...

Leos Bohac

2010-01-01

332

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...

Chih-Ying Huang; Shiuh-Chuan Her

2013-01-01

333

System performances of fiber optical parametric amplifiers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The research field of fiber optical parametric amplifiers has steadily expanded over the last two decades as a host of all-optical signal processing techniques have been demonstrated in nonlinear optical fibers such as wavelength conversion, optical regeneration, optical switching, limiting, buffering, and sampling. This article reviews the system performances of theses parametric devices such as gain bandwidth, focuses on the main limitations and demonstrates efficient techniques for suppres...

Sylvestre, T.; Mussot, A.; Vedadi, A.; Provino, L.; Lantz, E.; Maillotte, H.

2009-01-01

334

Engineering metal oxide nanostructures for the fiber optic sensor platform.  

Science.gov (United States)

This paper presents an effective integration scheme of nanostructured SnO2 with the fiber optic platform for chemical sensing applications based on evanescent optical interactions. By using a triblock copolymer as a structure directing agent as the means of nano-structuring, the refractive index of SnO2 is reduced from >2.0 to 1.46, in accordance with effective medium theory for optimal on-fiber integration. High-temperature stable fiber Bragg gratings inscribed in D-shaped fibers were used to perform real-time characterization of optical absorption and refractive index modulation of metal oxides in response to NH3 from the room temperature to 500 °C. Measurement results reveals that the redox reaction of the nanostructured metal oxides exposed to a reactive gas NH3 induces much stronger changes in optical absorption as opposed to changes in the refractive index. Results presented in this paper provide important guidance for fiber optic chemical sensing designs based on metal oxide nanomaterials. PMID:24663558

Poole, Zsolt L; Ohodnicki, Paul; Chen, Rongzhang; Lin, Yuankun; Chen, Kevin P

2014-02-10

335

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...

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

2013-01-01

336

New Methods of Enhancing the Thermal Durability of Silica Optical Fibers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Microstructured optical fibers can be precisely tailored for many different applications, out of which sensing has been found to be particularly interesting. However, placing silica optical fiber sensors in harsh environments results in their quick destruction as a result of the hydrolysis process. In this paper, the degradation mechanism of bare and metal-coated optical fibers at high temperatures under longitudinal strain has been determined by detailed analysis of the thermal behavior of s...

Karol Wysoki?ski; Tomasz Sta?czyk; Katarzyna Giba?a; Tadeusz Tenderenda; Anna Zio?owicz; Mateusz S?owikowski; Ma?gorzata Broczkowska; Tomasz Nasi?owski

2014-01-01

337

Enhancing Optical Communications with Brand New Fibers  

DEFF Research Database (Denmark)

Optical fibers have often been considered to offer effectively infinite capacity to support the rapid traffic growth essential to our information society. However, as demand has grown and technology has developed, we have begun to realize that there is a fundamental limit to fiber capacity of ~ 100 Tb/s per fiber for systems based on conventional single-core single-mode optical fiber as the transmission medium. This limit arises from the interplay of a number of factors including the Shannon limit, optical fiber nonlinearities, the fiber fuse effect, as well as optical amplifier bandwidth. This article reviews the most recent research efforts around the globe launched over the past few years with a view to overcome these limitations and substantially increase capacity by exploring the last degree of freedom available: the spatial domain. Central to this effort has been the development of brand new fibers for space-division multiplexing and mode-division multiplexing.

Morioka, Toshio; Awaji, Yoshinari

2012-01-01

338

Grazing incidence angle based sensing approach integrated with fiber-optic Fourier transform infrared (FO-FTIR) spectroscopy for remote and label-free detection of medical device contaminations  

Science.gov (United States)

Contamination of medical devices has become a critical and prevalent public health safety concern since medical devices are being increasingly used in clinical practices for diagnostics, therapeutics and medical implants. The development of effective sensing methods for real-time detection of pathogenic contamination is needed to prevent and reduce the spread of infections to patients and the healthcare community. In this study, a hollow-core fiber-optic Fourier transform infrared spectroscopy methodology employing a grazing incidence angle based sensing approach (FO-FTIR-GIA) was developed for detection of various biochemical contaminants on medical device surfaces. We demonstrated the sensitivity of FO-FTIR-GIA sensing approach for non-contact and label-free detection of contaminants such as lipopolysaccharide from various surface materials relevant to medical device. The proposed sensing system can detect at a minimum loading concentration of approximately 0.7 ?g/cm2. The FO-FTIR-GIA has the potential for the detection of unwanted pathogen in real time.

Hassan, Moinuddin; Ilev, Ilko

2014-10-01

339

Grazing incidence angle based sensing approach integrated with fiber-optic Fourier transform infrared (FO-FTIR) spectroscopy for remote and label-free detection of medical device contaminations  

Energy Technology Data Exchange (ETDEWEB)

Contamination of medical devices has become a critical and prevalent public health safety concern since medical devices are being increasingly used in clinical practices for diagnostics, therapeutics and medical implants. The development of effective sensing methods for real-time detection of pathogenic contamination is needed to prevent and reduce the spread of infections to patients and the healthcare community. In this study, a hollow-core fiber-optic Fourier transform infrared spectroscopy methodology employing a grazing incidence angle based sensing approach (FO-FTIR-GIA) was developed for detection of various biochemical contaminants on medical device surfaces. We demonstrated the sensitivity of FO-FTIR-GIA sensing approach for non-contact and label-free detection of contaminants such as lipopolysaccharide from various surface materials relevant to medical device. The proposed sensing system can detect at a minimum loading concentration of approximately 0.7 ?g/cm{sup 2}. The FO-FTIR-GIA has the potential for the detection of unwanted pathogen in real time.

Hassan, Moinuddin, E-mail: moinuddin.hassan@fda.hhs.gov; Ilev, Ilko [Optical Therapeutics and Medical Nanophotonics Laboratory, Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland 20993 (United States)

2014-10-15

340

Grazing incidence angle based sensing approach integrated with fiber-optic Fourier transform infrared (FO-FTIR) spectroscopy for remote and label-free detection of medical device contaminations  

International Nuclear Information System (INIS)

Contamination of medical devices has become a critical and prevalent public health safety concern since medical devices are being increasingly used in clinical practices for diagnostics, therapeutics and medical implants. The development of effective sensing methods for real-time detection of pathogenic contamination is needed to prevent and reduce the spread of infections to patients and the healthcare community. In this study, a hollow-core fiber-optic Fourier transform infrared spectroscopy methodology employing a grazing incidence angle based sensing approach (FO-FTIR-GIA) was developed for detection of various biochemical contaminants on medical device surfaces. We demonstrated the sensitivity of FO-FTIR-GIA sensing approach for non-contact and label-free detection of contaminants such as lipopolysaccharide from various surface materials relevant to medical device. The proposed sensing system can detect at a minimum loading concentration of approximately 0.7 ?g/cm2. The FO-FTIR-GIA has the potential for the detection of unwanted pathogen in real time

 
 
 
 
341

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

342

Actively Heated Fiber Optic Method for Distributed Soil Moisture Monitoring  

Science.gov (United States)

The temporal and spatial distribution of soil water at scales from 1 to 10,000m is both poorly understood and critical to terrestrial processes. Areas of great uncertainty include the spatio-temporal patterns of: soil water; evapo-transpiration; recharge during and following rainfalls. Observation of dynamics at these scales requires an innovative measurement approach. A novel in-situ distributed measurement of soil water content using temperature measured with Raman scattering in fiber optic cables is presented. This technology, called “Actively Heated Fiber Optic Method,” demonstrated in the lab setting by Sayde et al. 2010 in Water Resources Research involves use of a heat pulse method with fiber optic temperature sensing to obtain precise, distributed measurements of soil water content, with high temporal resolution and sub-meter scale spatial resolution, along a fiber optic cable that can exceed several km in length. The method is based on the influence of water content on soil thermal properties as observed with a buried fiber optical cable monitored by a laser Raman backscatter DTS system. The buried fiber optic is actively heated via electrical resistance, using the steel elements that surround the fiber, and the optical fiber is used as a sub-meter scale thermal sensor to monitor the changes in soil thermal responses every meter along the fiber optic cable. A response metric that has not been previously employed “the time integral of temperature deviation” is used as a simple interpretation of heat data that takes advantage of the characteristics of fiber optic measurements. Validation of the method based on large-column laboratory tests, and field testing results using and 750 m of fiber optic cable buried at 30, 60, and 90 cm depth in the field are presented. The results indicate the feasibility of using the actively heated fiber optic method to monitor soil water content at temporal resolution well under one hour and spatial resolution of 1 m. In principle, this DTS method could monitor soil moisture along cables exceeding 10,000 m in extent. Such measurements could be transformative in our understanding of soil hydrology in natural and managed systems at field and watershed scales.

Sayde, C.; Selker, J. S.; Rodriguez-Sinobas, L.; Gil-Rodriguez, M.; Cuenca, R. H.; Tyler, S. W.; English, M.

2010-12-01

343

Optical fiber lasers and amplifiers  

Energy Technology Data Exchange (ETDEWEB)

An optical fiber is described, which comprises: a substantially single-mode core having an index of refraction n/sub 1/ comprised of laser material disposed within a multi-mode cladding having an index of refraction n/sub 2/; and a further cladding having an index of refraction n/sub 3/ surrounding the multi-mode cladding with substantially no space between the further cladding and the multi-mode cladding; wherein the single-mode core is disposed at an offset from the geometric center of the multi-mode cladding.

Snitzer, E.; Po, H.; Tumminelli, R.P.; Hakimi, F.

1989-03-21

344

Recent advances toward a fiber optic sensor for nerve agent  

Science.gov (United States)

We report advances made on the development of a fiber optic nerve agent sensor having its entire length as the sensing element. Upon exposure to sarin gas or its simulant, diisopropyl fluorophosphate, the cladding changes color resulting in an alteration of the light intensity throughput. The optical fiber is multimode and consists of a fused-silica core and a nerve agent sensitive cladding. The absorption characteristics of the cladding affect the fiber's spectral attenuation and limit the length of light guiding fiber that can be deployed continuously. The absorption of the cladding is also dependent on the sensor formulation, which in turn influences the sensitivity of the fiber. In this paper, data related to the trade-off of sensitivity, spectral attenuation, and length of fiber challenged will be reported. The fiber is mass produced using a conventional fiber optic draw tower. This technology could be used to protect human resources and buildings from dangerous chemical attacks, particularly when large areas or perimeters must be covered. It may also be used passively to determine how well such areas have been decontaminated.

Beshay, Manal; Cordero, Steven R.; Mukamal, Harold; Ruiz, David; Lieberman, Robert A.

2008-04-01

345

Ec-135 Fiber Optic Technology Review  

Science.gov (United States)

Fiber optic technology offers many advantages for upgrading nuclear survivability in systems such as the Airborne Command Post EC-135 aircraft, including weight and cost savings, EMI and EMC immunity, high data rates. The greatest advantage seen for nuclear survivable systems, however, is that a fiber optic system's EMP hardness can be maintained more easily with the use of fiber optics than with shielded cables or other protective methods. TRW recently completed a study to determine the feasibility of using fiber optic technology in an EC-135 aircraft environment. Since this study was conducted for a USAF Logistics Command Agency, a feasible system had to be one which could be realistically priced by an integrating contractor. Thus, any fiber optic approach would have to be well developed before it could be considered feasible. During the course of the study problem areas were encountered which are associated with the readiness of the technology for use rather than with the technology itself. These included connectors, standards, fiber radiation resistance, busing, maintenance, and logistics. Because these problems areas have not been resolved, it was concluded that fiber optic technology, despite its advantages, is not ready for directed procurement (i.e., included as a requirement in a prime mission equipment specification). However, offers by a manufacturer to use fiber optic technology in lieu of conventional technology should be considered. This paper treats these problems in more detail, addresses the areas which need further development, and discusses the hardness maintenance advantages of using fiber optic technology.

Schultz, Jan R...; Hodges, Harry N.

1984-10-01

346

Optical fiber accelerometer based on MEMS torsional micromirror  

Science.gov (United States)

A novel structure of optical fiber accelerometer based on MEMS torsional micro-mirror is introduced, including MEMS torsional micro-mirror and optical signal detection. The micro-mirror is a non-symmetric one, which means that the torsional bar supporting the micro-mirror is not located in the axis where the center of the micro-mirror locates. The optical signal detection is composed of PIN diode and dual fiber collimator, which is very sensitive to the coupling angle between the input fiber and output fiber. The detection principle is that acceleration is first transformed into torsional angle of the micro-mirror, then, optical insertion loss of the dual fiber collimator caused by the angle can be received by PIN. So under the flow of acceleration to torsional angle to optical signal attenuation to optical power detection, the acceleration is detected. The theory about sensing and optical signal detect of the device are discussed in this paper. The sensitive structure parameters and performance parameters are calculated by MATLAB. To simulate the static and modal analysis, the finite element analysis, ANSYS, is employed. Based on the above calculation, several optimization methods and the final structure parameters are given. The micro-mirror is completed by using silicon-glass bonding and deep reactive ion etching (DRIE). In the experiment, the acceleration is simulated by electrostatic force and the test results show that the static acceleration detection agrees with the theory analysis very well.

Zeng, Fanlin; Zhong, Shaolong; Xu, Jing; Wu, Yaming

2008-03-01

347

Fiber optic quasi-distributed sensors for water leak detection  

Science.gov (United States)

A fiber optic quasi-distributed sensing technique was suggested to use for detecting the location and severity of water leakage. A novel fiber optic sensor probe was devised with a vessel of water absorption material called as water combination soil (WCS) located between two highly reflected connectors. The largest vessel probe provides the highest sensitivity, 0.267 dB/ml, while the small one shows relatively low sensitivity, 0.067 dB/ml, and unstable response. The sensor probe with a high output value provides a high sensitivity with various detection levels while the number of total installable sensor probes decreases.

Cho, Tae-Sik; Kwon, Il-Bum

2013-08-01

348

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

349

Radiation damage in commercial optical fibers  

International Nuclear Information System (INIS)

Experimental results obtained by exposure of commercial optical fibers to 60Co ?-ray irradiation, are reported. The possibility of utilizing these fibers as far as a total dose of 6000 rad in the light spectrum is shown. It is also shown that it is possible to obtain total recovery of irradiated fibers by annealing at 5000C. (author)

350

Fiber optic sensors IV; Proceedings of the Third European Congress on Optics, The Hague, Netherlands, Mar. 13, 14, 1990  

Science.gov (United States)

Recent advances in fiber-optic sensor (FOS) technology are examined in reviews and reports. Sections are devoted to components for FOSs, special fibers for FOSs, interferometry, FOS applications, and sensing principles and influence. Particular attention is given to solder glass sealing technology for FOS packaging, the design of optical-fiber current sensors, pressure and temperature effects on beat length in highly birefringent optical fibers, a pressure FOS based on vibrating-quartz-crystal technology, remote sensing of flammable gases using a fluoride-fiber evanescent probe, a displacement sensor with electronically scanned white-light interferometer, the use of multimode laser diodes in low-coherence coupled-cavity interferometry, electronic speckle interferometry compensated for environmentally induced phase noise, a dual-resolution noncontact vibration and displacement sensor based on a two-wavelength source, and fiber optics in composite materials.

Kersten, Ralf T.

1990-08-01

351

An optical fiber optofluidic particle aspirator  

Science.gov (United States)

A fiberized optofluidic particle trapping device based on a micro-slot fabricated in a standard single-mode optical fiber by femtosecond laser micromachining is demonstrated. While fluidic convective motions move a large number of microparticles into the slot, the optical mode propagating in the nearby optical fiber core is exploited to trap and propel the particles inside the slot, thereby facilitating their collection at one of the slot extremities. The combined effect of fluidic and optical trapping allows for the collection of particles from as far as 60 ?m away from the optical trap. Application to particle and live cell trapping and propulsion is demonstrated.

Murugan, Ganapathy S.; Belal, Mohammad; Grivas, Christos; Ding, Ming; Wilkinson, James S.; Brambilla, Gilberto

2014-09-01

352

Laboratory Equipment Type Fiber Optic Refractometer  

Directory of Open Access Journals (Sweden)

Full Text Available Using fiber optics and micro optics technologies we designed aninnovative fiber optic index of refraction transducer that has uniqueproperties. On the base of this transducer a laboratory equipment typefiber optic refractometer was developed for liquid index of refractionmeasurements. Such refractometer may be used for medical,pharmaceutical, industrial fluid, petrochemical, plastic, food, andbeverage industry applications. For example, it may be used formeasuring the concentrations of aqueous solutions: as the concentrationor density of a solute increase, the refractive index increasesproportionately. The paper describes development work related to designof laboratory type fiber optic refractometer and describes experimentsto evaluation of its basic properties.

E. F. Carome

2002-09-01

353

Laser beam shaping inside an optical fiber  

International Nuclear Information System (INIS)

Some laser applications like the injection line of powerful lasers requires a very uniform laser beam spatial profile. Such a profile is usually obtained by using expensive optic components that are difficult to align. A new solution consists of shaping the laser beam not in the open air but inside an optic fiber. We have created a micro-structured optic fiber whose propagation mode is not Gaussian as usual but is of a flattened shape. This optic fiber will replace the optic component dedicated to spatial shaping of the laser beam, this function is usually made by phase mirrors located in the first stage of the amplification process

354

A fiber optics textile composite sensor for geotechnical applications  

Science.gov (United States)

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

Artières, Olivier; Dortland, Gerrit

2010-09-01

355

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

356

Fiber optic (flight quality) sensors for advanced aircraft propulsion  

Science.gov (United States)

Development of flight prototype, fiber-optic sensing system components for measuring nine sensed parameters (three temperatures, two speeds, three positions, and one flame) on an F404-400 aircraft engine is described. Details of each sensor's design, functionality, and environmental testing, and the electro-optics architecture for sensor signal conditioning are presented. Eight different optical sensing techniques were utilized. Design, assembly, and environmental testing of an engine-mounted, electro-optics chassis unit (EOU), providing MIL-C-1553 data output, are related. Interconnection cables and connectors between the EOU and the sensors are identified. Results of sensor/cable/circuitry integrated testing, and installation and ground testing of the sensor system on an engine in October 1993 and April 1994 are given, including comparisons with the engine control system's electrical sensors. Lessons learned about the design, fabrication, testing, and integration of the sensor system components are included.

Poppel, Gary L.

1994-01-01

357

Compact fiber optic gyroscopes for platform stabilization  

Science.gov (United States)

SA Photonics has developed a family of compact Fiber Optic Gyroscopes (FOGs) for platform stabilization applications. The use of short fiber coils enables the high update rates required for stabilization applications but presents challenges to maintain high performance. We are able to match the performance of much larger FOGs by utilizing several innovative technologies. These technologies include source noise reduction to minimize Angular Random Walk (ARW), advanced digital signal processing that minimizes bias drift at high update rates, and advanced passive thermal packaging that minimizes temperature induced bias drift while not significantly affecting size, weight, or power. In addition, SA Photonics has developed unique distributed FOG packaging technologies allowing the FOG electronics and photonics to be packaged remotely from the sensor head or independent axis heads to minimize size, weight, and power at the sensing location(s). The use of these technologies has resulted in high performance, including ARW less than 0.001 deg/rt-hr and bias drift less than 0.004 deg/hr at an update rate of 10 kHz, and total packaged volume less than 30 cu. in. for a 6 degree of freedom FOG-based IMU. Specific applications include optical beam stabilization for LIDAR and LADAR, beam stabilization for long-range free-space optical communication, Optical Inertial Reference Units for HEL stabilization, and Ka band antenna pedestal pointing and stabilization. The high performance of our FOGs also enables their use in traditional navigation and positioning applications. This paper will review the technologies enabling our high-performance compact FOGs, and will provide performance test results.

Dickson, William C.; Yee, Ting K.; Coward, James F.; McClaren, Andrew; Pechner, David A.

2013-09-01

358

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 ...

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

2010-01-01

359

Optical fibers in broadband networks, instrumentation, and urban and industrial environments; Proceedings of the Meeting, Paris, France, May 16-19, 1983  

Science.gov (United States)

Developments related to optical fibers in broadband networks are discussed, taking into account questions regarding the development of videocommunications cable networks, CATV fiberoptic cable markets in the U.S., new directions in videocommunications, the present status of local area network systems using optical fibers in Japan, developments toward a general integrated broadband optical fiber telecommunications network in the subscriber area, an interactive teledistribution network using fiber optic technologies, and the methodology for cost optimization of a wideband optical fiber network. Other topics explored are connected with optical fibers in instrumentation, optical fibers in urban and industrial environments, new technologies and international cooperation, and a mixed optoelectrical cable for a color camera link. Attention is given to the characteristics of fiber optic radiation detectors, a fiber optical system in remote sensing instrumentation, optical fibers in the industrial and commercial environment, and optical fiber systems related to space applications.

Boucher, D.

1983-01-01

360

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

 
 
 
 
361

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

362

Multimode optical fiber radiation modal decomposition  

CERN Document Server

We proposed the method of the optical fiber modal decomposition of the radiation propagating in a multimode optical fiber with a step like refractive index profile. The field distribution at the output end of the fiber was used. The method is based on the field decomposition by non-orthogonal modes. The full complex expansion coefficients of the light field were calculated for theoretical data.

Bolshakov, M V; Kundikova, N D

2013-01-01

363

Fiber optic applications in nuclear power plants  

International Nuclear Information System (INIS)

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

364

Fiber optic applications in nuclear power plants  

International Nuclear Information System (INIS)

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

365

Measuring Longitudinal Strain In Optical Fibers  

Science.gov (United States)

The measurement of longitudinal strain of optical fibers using several optical techniques is discussed. A review of the optical principles used to design each measurement system is included. Mathematical expressions for strain due to tensile stress, thermal stress, and hydrostatic pressure are provided. Each technique is based upon directly or indirectly measuring the change in the transit time of an optical signal injected into the test fiber. Equations are provided that relate the strain to the change in fiber transit time. Examples of calibration results and cable tests are given.

Brininstool, Michael R.

1987-11-01

366

Bio-chemical sensor based on imperfected plastic optical fiber  

Science.gov (United States)

In this paper we report results for an intrinsic evanescent field sensor based on not-regular plastic optical fiber with polymer film containing Malachite Green MG +([PhC(C 6H 4NMe II) 3] +) as an absorption reagent, which coats the fiber's imperfected area. A theoretical model was developed which shows that changes of light in such structure result from the attenuation of light in the strait and bent imperfected fiber. In this model, the imperfected area with malachite green polymer film is replaced by a uniform layer with a complex refractive index. The changes in color and absorption characteristics of the polymer film depend on the acidic and basic environmental properties in the sensing area. Additional increase of the evanescent field interaction can be achieved by decrease the bending radius of the fiber with the coated imperfection area at the middle of the bent fiber. An imperfected plastic optical fiber with Malachite Green coating has been presented for the detection of ammonia vapor. The initial results show that depending on the sensing application demands, it is possible to design a high sensitive sensor with a relatively long response time, while when the demands require fast response times the sensor with less sensitivity can be used. In addition, the sensors' sensitivity can be calibrated in real-time by changing the bending radius.

Babchenko, Anatoly; Chernyak, Valeri; Maryles, Jonathan

2007-05-01

367

Fiber optic liquid level sensor system for aerospace applications  

Science.gov (United States)

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

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

2014-09-01

368

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. PMID:24509982

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

2014-01-01

369

Synopsis of fiber optics in harsh environments  

Science.gov (United States)

Fiber optic technology is making significant advances for use in a number of harsh environments, such as air and space platforms. Many of these applications involve integration into systems which make extensive use of optical fiber for high bandwidth signal transmission. The large signal transmission bandwidth of optical fiber has a large and positive impact on the overall performance and weight of the cable harness. There are many benefits of fiber optic systems for air and space harsh environment applications, including minimal electromagnetic interference and environmental effects, lightweight and smaller diameter cables, greater bandwidth, integrated prognostics and diagnostics and the ability to be easily upgraded. To qualify and use a fiber optic cable in space and air harsh environments requires treatment of the cable assembly as a system and understanding the design and behavior of its parts. Many parameters affect an optical fiber's ability to withstand a harsh temperature and radiation environment. The space radiation environment is dependent on orbital altitude, inclination and time, contains energetic magnetically-trapped electrons in the outer Van Allen radiation belt, trapped protons in the inner belt and solar event protons and ions. Both transient and permanent temperature and radiation have an attenuation effect on the performance of the cable fiber. This paper presents an overview of defining fiber optic system and component performance by identifying operating and storage environmental requirements, using appropriate standards to be used in fiber optic cable assembly manufacturing and integration, developing inspection methods and fixtures compliant with the selected standards and developing a fiber optic product process that assures compliance with each design requirement.

Pirich, Ronald

2014-09-01

370

Fiber-optic magnetic-field imaging.  

Science.gov (United States)

We demonstrate a scanning fiber-optic probe for magnetic-field imaging where nitrogen-vacancy (NV) centers are coupled to an optical fiber integrated with a two-wire microwave transmission line. The electron spin of NV centers in a diamond microcrystal attached to the tip of the fiber probe is manipulated by a frequency-modulated microwave field and is initialized by laser radiation transmitted through the optical tract of the fiber probe. The two-dimensional profile of the magnetic field is imaged with a high speed and high sensitivity using the photoluminescence spin-readout return from NV centers, captured and delivered by the same optical fiber. PMID:25503039

Fedotov, I V; Doronina-Amitonova, L V; Sidorov-Biryukov, D A; Safronov, N A; Blakley, S; Levchenko, A O; Zibrov, S A; Fedotov, A B; Kilin, S Ya; Scully, M O; Velichansky, V L; Zheltikov, A M

2014-12-15

371

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

Science.gov (United States)

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

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

2014-07-01

372

Micromachined fiber optic Fabry-Perot underwater acoustic probe  

Science.gov (United States)

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

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

2014-08-01

373

All-fiber resonator fiber optic gyroscope (R-FOG) using a spliceless phase-modulation fiber resonator with 90-deg polarization rotation in the lapped coupler  

Science.gov (United States)

The experimental demonstration of an all-fiber resonator optic gyroscope employing a spliceless PM-fiber resonator with 90 degree(s) polarization rotation in the lapped coupler is presented. A Frequency Modulation spectroscopy technique has been demonstrated for rotation sensing using two piezoelectric transducer phase modulators. The short term bias stability better than 16 degree/hr with integration time of 10 sec has been obtained. The main error sources of optical system are discussed and some reduction measures are suggested.

Yao, Yi; Shi, Kun; Lu, Weidong; Jian, Shuisheng; Zhang, Weixu

1994-11-01

374

Optical fiber voltage sensors for broad temperature ranges  

Science.gov (United States)

We describe the development of an optical fiber ac voltage sensor for aircraft and spacecraft applications. Among the most difficult specifications to meet for this application is a temperature stability of +/- 1 percent from -65 C to +125 C. This stability requires a careful selection of materials, components, and optical configuration with further compensation using an optical-fiber temperature sensor located near the sensing element. The sensor is a polarimetric design, based on the linear electro-optic effect in bulk Bi4Ge3O12. The temperature sensor is also polarimetric, based on the temperature dependence of the birefringence of bulk SiO2. The temperature sensor output is used to automatically adjust the calibration of the instrument.

Rose, A. H.; Day, G. W.

1992-12-01

375

Orbital angular momentum in optical fibers  

Science.gov (United States)

Internet data traffic capacity is rapidly reaching limits imposed by nonlinear effects of single mode fibers currently used in optical communications. Having almost exhausted available degrees of freedom to orthogonally multiplex data in optical fibers, researchers are now exploring the possibility of using the spatial dimension of fibers, via multicore and multimode fibers, to address the forthcoming capacity crunch. While multicore fibers require complex manufacturing, conventional multi-mode fibers suffer from mode coupling, caused by random perturbations in fibers and modal (de)multiplexers. Methods that have been developed to address the problem of mode coupling so far, have been dependent on computationally intensive digital signal processing algorithms using adaptive optics feedback or complex multiple-input multiple-output algorithms. Here we study the possibility of using the orbital angular momentum (OAM), or helicity, of light, as a means of increasing capacity of future optical fiber communication links. We first introduce a class of specialty fibers designed to minimize mode coupling and show their potential for OAM mode generation in fibers using numerical analysis. We then experimentally confirm the existence of OAM states in these fibers using methods based on fiber gratings and spatial light modulators. In order to quantify the purity of created OAM states, we developed two methods based on mode-image analysis, showing purity of OAM states to be 90% after 1km in these fibers. Finally, in order to demonstrate data transmission using OAM states, we developed a 4-mode multiplexing and demultiplexing systems based on free-space optics and spatial light modulators. Using simple coherent detection methods, we successfully transmit data at 400Gbit/s using four OAM modes at a single wavelength, over 1.1 km of fiber. Furthermore, we achieve data transmission at 1.6Tbit/s using 10 wavelengths and two OAM modes. Our study indicates that OAM light can exist, and be long lived, in a special class of fibers and our data transmission demonstrations show that OAM could be considered an additional degree of freedom for data multiplexing in future optical fiber communication links. Our studies open the doors for other applications such as micro-endoscopy and nanoscale imaging which require fiber based remote delivery of OAM light.

Bozinovic, Nenad

376

Practical aspects of fiber optical parametric amplifiers for optical communication  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fiber optical parametric amplifiers (OPAs) are based on the third-order nonlinear susceptibility of glass fibers. If two strong pumps and a weak signal are fed into a fiber, an idler is generated. Signal and idler can grow together if pump power is high enough, and phase matching occurs. Until recently, impressive performance of fiber OPAs has been demonstrated in different respects. However, secondary effects should be addressed before OPAs can be utilized in practical applications. Here we ...

Wong, Kky

2010-01-01

377

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

378

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

379

The Soliton Transmissions in Optical Fibers  

Directory of Open Access Journals (Sweden)

Full Text Available 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 on the numerical solution of the nonlinear Schroedinger equation (NLSE, although in some specific cases it is possible to solve it analytically.

Leos Bohac

2010-01-01

380

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

 
 
 
 
381

Optical fiber sensors for high temperature harsh environment applications  

Science.gov (United States)

This paper summarizes our recent research progresses in developing optical fiber harsh environment sensors for various high temperature harsh environment sensing applications such as monitoring of the operating conditions in a coal-fired power plant and in-situ detection of key gas components in coal-derived syngas. The sensors described in this paper include a miniaturized inline fiber Fabry-Perot interferometer (FPI) fabricated by one-step fs laser micromachining, a long period fiber grating (LPFG) and a fiber inline core-cladding mode interferometer (CMMI) fabricated by controlled CO2 laser irradiations. Their operating principles, fabrication methods, and applications for measurement of various physical and chemical parameters in a high temperature and high pressure coexisting harsh environment are presented.

Xiao, Hai; Wei, Tao; Lan, Xinwei; Zhang, Yinan; Duan, Hongbiao; Han, Yukun; Tsai, Hai-Lung

2010-04-01

382

Robust optical fiber bending sensor to measure frequency of vibration  

Science.gov (United States)

A simple technique for sensing the acoustic vibration of a cantilever beam, using a single-fiber Mach-Zehnder interferometer, is presented. The interferometer consists of two concatenated low-loss fused fiber tapers, with a waist diameter of 60 ?m, separated by an un-tapered fiber section of 10 mm length. The interferometer transmitted signal is modulated when the device is bent under the presence of an external acoustic signal. The optical fiber device glued directly on a metallic cantilever beam is capable of measuring frequency of the resonant modes. The interrogation set-up is simple consisting of a single tunable diode laser and a photodetector. The measured frequencies of the resonating modes agree with the numerical results obtained by the Finite Element Method.

Hernández-Serrano, Arturo Ignacio; Salceda-Delgado, Guillermo; Moreno-Hernández, David; Martínez-Ríos, Alejandro; Monzón-Hernández, David

2013-09-01

383

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

2013-01-01

384

Polymer optical fiber bragg grating sensors : measuring acceleration  

DEFF Research Database (Denmark)

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

Stefani, Alessio; Yuan, Scott Wu

2010-01-01

385

Applicability of optical fiber Bragg grating in radiation environment  

International Nuclear Information System (INIS)

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

386

Attenuation in silica-based optical fibers  

DEFF Research Database (Denmark)

In this thesis on attenuation in silica based optical fibers results within three main topics are reported. Spectral attenuation measurements on transmission fibers are performed in the wide wavelength range 290 nm – 1700 nm. The measured spectral attenuation is analyzed with special emphasis on absorption peaks in order to investigate the cause of an unusual high attenuation in a series of transmission fibers. Strong indications point to Ni2+ in octahedral coordination as being the cause of the high attenuation. The attenuation of fibers having a high core refractive index is analyzed and the cause of the high attenuation measured in such fibers is described as being due to scattering of light on fluctuations of the core diameter. A novel semi-empirical model for predicting the attenuation of high index fibers is presented. The model is shown to be able to predict the attenuation of high index fibers having viscosity profiles similar to those for which the model was calibrated but not of fibers having dissimilar viscosity profiles. The model is improved by including the viscosity profiles of the fibers. A set of fibers is produced demonstrating that by carefully designing the index profile as well as the viscosity profile a lower attenuation of high index fibers can be obtained. The design of dispersion compensating fibers using the super mode approach is described, the object being to design dispersion compensating fibers for dispersion compensating fiber modules having a low attenuation, described by a high figure of merit. The major trade offs encountered when designing dispersion compensating fibers with high figure of merit are to obtain a very negative dispersion, low attenuation and low micro bend loss at the same time. The model for predicting the attenuation of high index fibers is used for the optimization process and results are reported of a dispersion compensating fiber having a record high figure of merit of 470 ps/(nm dB).

Wandel, Marie Emilie

2006-01-01

387

Electron spin manipulation and readout through an optical fiber  

Science.gov (United States)

The electron spin of nitrogen--vacancy (NV) centers in diamond offers a solid-state quantum bit and enables high-precision magnetic-field sensing on the nanoscale. Implementation of these approaches in a fiber format would offer unique opportunities for a broad range of technologies ranging from quantum information to neuroscience and bioimaging. Here, we demonstrate an ultracompact fiber-optic probe where a diamond microcrystal with a well-defined orientation of spin quantization NV axes is attached to the fiber tip, allowing the electron spins of NV centers to be manipulated, polarized, and read out through a fiber-optic waveguide integrated with a two-wire microwave transmission line. The microwave field transmitted through this line is used to manipulate the orientation of electron spins in NV centers through the electron-spin resonance tuned by an external magnetic field. The electron spin is then optically initialized and read out, with the initializing laser radiation and the photoluminescence spin-readout return from NV centers delivered by the same optical fiber.

Fedotov, I. V.; Doronina-Amitonova, L. V.; Voronin, A. A.; Levchenko, A. O.; Zibrov, S. A.; Sidorov-Biryukov, D. A.; Fedotov, A. B.; Velichansky, V. L.; Zheltikov, A. M.

2014-07-01

388

Electron spin manipulation and readout through an optical fiber.  

Science.gov (United States)

The electron spin of nitrogen--vacancy (NV) centers in diamond offers a solid-state quantum bit and enables high-precision magnetic-field sensing on the nanoscale. Implementation of these approaches in a fiber format would offer unique opportunities for a broad range of technologies ranging from quantum information to neuroscience and bioimaging. Here, we demonstrate an ultracompact fiber-optic probe where a diamond microcrystal with a well-defined orientation of spin quantization NV axes is attached to the fiber tip, allowing the electron spins of NV centers to be manipulated, polarized, and read out through a fiber-optic waveguide integrated with a two-wire microwave transmission line. The microwave field transmitted through this line is used to manipulate the orientation of electron spins in NV centers through the electron-spin resonance tuned by an external magnetic field. The electron spin is then optically initialized and read out, with the initializing laser radiation and the photoluminescence spin-readout return from NV centers delivered by the same optical fiber. PMID:25028257

Fedotov, I V; Doronina-Amitonova, L V; Voronin, A A; Levchenko, A O; Zibrov, S A; Sidorov-Biryukov, D A; Fedotov, A B; Velichansky, V L; Zheltikov, A M

2014-01-01

389

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

390

Hydrogen leak detection: a comparison between fiber optic sensors based on different designs  

Science.gov (United States)

We present a review of optical fiber hydrogen sensors based on Palladium. Palladium hydrogen optical fiber sensing system can be considered as a model for other metal hybrid system. Besides, the Palladium hydrogen, systems are well characterized in bulk, cluster or thin film form. We focus on the fiber principles. We discuss then their performances regarding their configurations. We will conclude by introducing the challenges for designing an ideal hydrogen optical fiber sensor based on metal hybrids approach and which designing direction seen the best to take.

Javahiraly, Nicolas; Perrotton, Cedric

2014-09-01

391

Attenuation in silica-based optical fibers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this thesis on attenuation in silica based optical fibers results within three main topics are reported. Spectral attenuation measurements on transmission fibers are performed in the wide wavelength range 290 nm – 1700 nm. The measured spectral attenuation is analyzed with special emphasis on absorption peaks in order to investigate the cause of an unusual high attenuation in a series of transmission fibers. Strong indications point to Ni2+ in octahedral coordination as being the cause o...

Wandel, Marie Emilie; Rottwitt, Karsten; Povlsen, Jørn Hedegaard

2007-01-01

392

Effect of Heating on Jacketed Optical Fibers  

Science.gov (United States)

Optical fibers installed in optoelectronic devices are frequently exposed to heat during assembly and inspection. In order to examine the effect of heating the fibers, the thermomechanical performance of a commercial fiber jacketed with a UV-cured acrylate was measured and partial delamination of the jacket materials between the primary and secondary coats was found after the test. Further, it is possible that delamination may occur even at temperatures less than the 80°C required for burn-in of the devices.

Nagata, Hirotoshi

2000-04-01

393

Continuous-wave fiber optical parametric oscillator.  

Science.gov (United States)

We report continuous-wave operation of singly resonant fiber optical parametric oscillators. In a cavity formed by 100 m of highly nonlinear fiber and two fiber Bragg gratings, the pump power threshold was 240 mW; the output wavelength could be tuned over 80 nm by tuning of the pump. We also obtained an internal conversion efficiency of 30%, compared with the maximum theoretical value of 50%, by use of a 1-km-long cavity. PMID:18026472

Marhic, M E; Wong, K K-Y; Kazovsky, L G; Tsai, T-E

2002-08-15

394

Exposed core microstructured optical fiber surface plasmon resonance biosensor  

Science.gov (United States)

Surface Plasmon Resonance (SPR) scattering offers significant advantages compared to traditional reflectivity measure- ments, essentially turning a non-radiative process into a radiative one. Recently, we have shown that SPR scattering can be used in an optical fiber, enabling higher signal to noise ratio, reduced dependence on the metallic thickness as well as the unique capability of multiplexed detection with a single fiber. Here we report a novel SPR scattering based sensor fabricated based on an exposed-core silica Microstructured Optical Fiber (MOF). This MOF presents a structure with a relatively small core (Ø = 10µm), exposed along the whole fiber length. This exposed core MOF allows for fabrication of SPR supporting metallic thin films directly onto the fiber core offering the new prospect of exploiting SPR in a waveguide structure that supports only a relatively small number of guided optical modes, with a structure that offers ease of fabri- cation and handling. A thin silver film of 50 nm thickness was deposited onto the fiber core by thermal evaporation. The significant surface roughness of the prepared metallic coatings facilitates strong scattering of the light wave coupled into the surface plasmon. Performance characteristics of the new exposed core fiber sensor were compared to those of a large bare core silica fiber (Ø = 140µm). Although sensitivity of both sensors was comparable (around 2500nm/RIU ), full width at half maximum (FWHM) of the SPR peaks for the new exposed core fiber sensor decreased by a factor of 3 offering an significant enhancement in the detection limit of the new sensing platform in addition to the prospect of a sensor with a lower detection volume.

Klantsataya, Elizaveta; François, Alexandre; Zuber, Agnieszka; Torok, Valeria; Kostecki, Roman; Monro, Tanya M.

2014-02-01

395

Application of Point and Distributed Optical Fiber Sensors to Health Monitoring of Smart Structures  

Science.gov (United States)

Point optical fiber sensors are useful in the monitoring of localized structural damage, but a large number of the sensors must be multiplexed for large structure monitoring. On the other hand, distributed optical fiber sensors can obtain a continuous distribution of strain or temperature with one sensing fiber, and they are suitable for the large structure monitoring due to their measurement range reaching tens of kilometers. However, the distributed sensors have the spatial resolution of tens of centimeters to several meters, and they measure averaged strain or temperature. In this paper, the application results of transmission-type extrinsic Fabry-Perot interferometric (TEFPI) optical fiber sensors and Brillouin distributed optical fiber sensors to structural monitoring are presented. The TEFPI optical fiber sensors and Brillouin distributed sensors were applied to the fatigue damage monitoring of an aluminum plate patched with CFRP composite and the deflection monitoring of an alumimum-bending beam, respectively.

Kim, Sang Hoon; Lee, Jung Ju; Seo, Dae Cheol; Lim, Jeong Ok

396

Effects of imperfect serrodyne phase modulation in resonator fiber optic gyroscopes  

Science.gov (United States)

In order for the resonator fiber optic gyroscope to achieve navigation grade performance, it must employ an optical frequency shifting technique for high scale factor accuracy. Serrodyne phase modulation commonly used in interferometric fiber optic gyros, has been considered a leading choice of modulation techniques. Here we present theoretical analysis on the effects of imperfect serrodyne phase modulation along with experimental results. A solution for substantially reducing the rotation sensing errors associated with imperfect serrodyne is also presented.

Strandjord, Lee K.; Sanders, Glen A.

1994-11-01

397

Fiber-optic color multiplexing system  

Science.gov (United States)

A fiber optic color multiplexed system has been developed which uses solid state light emitting diodes (LED) to obtain optical pulses in different colors in the visible range. By color coding, the information capacity of a communication system using LED sources can be expanded. A block diagram of the proposed system is presented and the operation of its major components, such as fiber optic color bidirectional transmission system, optical combiner, and light source driver is discussed. Measurements of multiplexing losses show that they are apparently independent of the number of input or output fibers in the combiner or decombiner, but the power dispersion tends to increase with the number of fibers in the decombiner.

Zaman, M. K.

1980-01-01

398

Laser drawing of optical fibers.  

Science.gov (United States)

A system consisting of a cw CO(2) laser and an ellipsoidal reflector was developed in order to draw fused silica fibers from bulk material. The system was used to obtain unclad fused silica fibers (Suprasil 2) having a total transmission loss of less than 100 dB/km at 6328 A. Preforms (rod in tube) have also been drawn to fibers of long lengths with diameters as small as 10 microm and variations within 5%. Analysis of the fiber drawing process established relations that allow determination of the design parameters for fiber drawing systems. Experimental results are given that support these relationships. PMID:20126202

Paek, U C

1974-06-01

399

Crystallization of compound plastic optical fibers  

Energy Technology Data Exchange (ETDEWEB)

Melt-spinning processes are often used to manufacture optical, textile, electrically conducting and reinforced fibers. This paper proposed a single-phase two-dimensional model of the spinning of compound plastic optical fibers that used a Newtonian rheology modified by the degrees of crystallization and molecular orientation. The model accounted for temperature through an effective dynamic viscosity, and the molecular orientation of the liquid crystalline polymer through an orientation parameter that depended on the velocity field. For slender fibers, an asymptotic procedure based on the slenderness ratio showed that the temperature was uniform across the compound fiber provided that the Biot number was in the order of the fourth power of the slenderness ratio and the leading-order equations for the fiber's geometry and axial velocity component, temperature, molecular orientation and crystallization were one-dimensional. This paper also proposed a two-dimensional model based on the leading-order equations for the fiber's geometry and velocity for slender fibers. This model provided the two-dimensional fields of temperature, molecular orientation and degree of crystallization and indicated that for moderate Biot numbers, the temperature distribution across the fiber was not uniform and a thermal boundary layer was formed on the outer surface of the compound fiber. The study showed that the crystallization of the compound fiber affected primarily by thermal effects rather than by flow-induced effects. 17 refs., 1 tab., 7 figs.

Ramos, J.I.; Blanco-Rodriguez, F.J. [Malaga Univ., Malaga (Spain). School of Engineering

2010-07-01

400

Fiber-Optic Vibration Sensor Based on Multimode Fiber  

Directory of Open Access Journals (Sweden)

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

I. Lujo

2008-06-01

 
 
 
 
401

Fiber-optic sensor for butylamine  

International Nuclear Information System (INIS)

Fiber-optic chemical sensor for butylamine was realized. The sensor includes a thin layer nanostructure on the end of optical fiber with a diameter of 600 ?m. It consists of luminescent silica nanoparticles modified with pyrylocyanine dye, silver nanoparticles and photonic-crystal film. The sensitivity of the sensor is increased tenfold due to an additional covering of the film with photonic crystal as a porous mirror and the injection of silver nanoparticles with a diameter of 5-7 nm.

402

Fiber-optic sensor for butylamine  

Science.gov (United States)

Fiber-optic chemical sensor for butylamine was realized. The sensor includes a thin layer nanostructure on the end of optical fiber with a diameter of 600 ?m. It consists of luminescent silica nanoparticles modified with pyrylocyanine dye, silver nanoparticles and photonic-crystal film. The sensitivity of the sensor is increased tenfold due to an additional covering of the film with photonic crystal as a porous mirror and the injection of silver nanoparticles with a diameter of 5-7 nm.

Boldov, I. A.; Kuchyanov, A. S.; Plekhanov, A. I.; Orlova, N. A.; Kargapolova, I. Yu; Shelkovnikov, V. V.

2011-04-01

403

Fresnel drag effect in fiber optic gyroscope  

Science.gov (United States)

Consideration is given to the development of a low-noise fiber-optic ring interferometer gyroscope. A technique for measuring the Fresnel drag coefficient of optical fibers is described, and the accuracy of the technique is considered. An experiment is performed which allows verification of the Einstein velocity addition theorem to the first nonlinear term. An experimental setup for measuring Fresnel drag is described: it consists of a Sagnac interferometer and a Fresnel drag measurement configuration.

Vali, V.; Berg, M. F.; Shorthill, R. W.

1978-01-01

404

Optical isolator system for fiber-optic uses  

Science.gov (United States)

A low loss optical isolator suitable for fiber-optic uses has been assembled from commercial components. The isolator exhibits reverse isolation of greater than 70 dB, with a forward loss of less than 1.3dB. This system provides an effective approach for reducing instabilities encountered in the output signal of semiconductor lasers in certain applications of fiber-optic systems. The paper presents a phenomenological explanation for the superior performance of the isolator system.

Lutes, George

1988-01-01

405

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

406

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

Science.gov (United States)

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.

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

2010-06-01

407

Real-time optical fiber dosimeter probe  

Science.gov (United States)

There is a pressing need for a passive optical fiber dosimeter probe for use in real-time monitoring of radiation dose delivered to clinical radiation therapy patients. An optical fiber probe using radiochromic material has been designed and fabricated based on a thin film of the radiochromic material on a dielectric mirror. Measurements of the net optical density vs. time before, during, and after irradiation at a rate of 500cGy/minute to a total dose of 5 Gy were performed. Net optical densities increased from 0.2 to 2.0 for radiochromic thin film thicknesses of 2 to 20 ?m, respectively.

Croteau, André; Caron, Serge; Rink, Alexandra; Jaffray, David; Mermut, Ozzy

2011-03-01

408

Optical system components for navigation grade fiber optic gyroscopes  

Science.gov (United States)

Interferometric fiber optic gyroscopes belong to the class of inertial sensors. Due to their high accuracy they are used for absolute position and rotation measurement in manned/unmanned vehicles, e.g. submarines, ground vehicles, aircraft or satellites. The important system components are the light source, the electro optical phase modulator, the optical fiber coil and the photodetector. This paper is focused on approaches to realize a stable light source and fiber coil. Superluminescent diode and erbium doped fiber laser were studied to realize an accurate and stable light source. Therefor the influence of the polarization grade of the source and the effects due to back reflections to the source were studied. During operation thermal working conditions severely affect accuracy and stability of the optical fiber coil, which is the sensor element. Thermal gradients that are applied to the fiber coil have large negative effects on the achievable system accuracy of the optic gyroscope. Therefore a way of calculating and compensating the rotation rate error of a fiber coil due to thermal