Self-compensating fiber optic flow sensor having an end of a fiber optics element and a reflective surface within a tube

DOEpatents

Peng, Wei; Qi, Bing; Wang, Anbo

2006-05-16

A flow rate fiber optic transducer is made self-compensating for both temperature and pressure by using preferably well-matched integral Fabry-Perot sensors symmetrically located around a cantilever-like structure. Common mode rejection signal processing of the outputs allows substantially all effects of both temperature and pressure to be compensated. Additionally, the integral sensors can individually be made insensitive to temperature.

Modeling and testing of fast response, fiber-optic temperature sensors

NASA Astrophysics Data System (ADS)

Tonks, Michael James

The objective of this work was to design, analyze and test a fast response fiber-optic temperature probe and sensor. The sensor is intended for measuring rapid temperature changes such as produced by a blast wave formed by a detonation. This work was performed in coordination with Luna Innovations Incorporated, and the design is based on extensions of an existing fiber-optic temperature sensor developed by Luna. The sensor consists of a glass fiber with an optical wafer attached to the tip. A basic description of the principles behind the fiber-optic temperature sensor and an accompanying demodulation system is provided. For experimental validation tests, shock tubes were used to simulate the blast wave experienced at a distance of 3.0 m from the detonation of 22.7 kg of TNT. The flow conditions were predicted using idealized shock tube theory. The temperature sensors were tested in three configurations, flush at the end of the shock tube, extended on a probe 2.54 cm into the flow and extended on a probe 12.7 cm into the flow. The total temperature was expected to change from 300 K to 1130 K for the flush wall experiments and from 300 K to 960 K for the probe experiments. During the initial 0.1 milliseconds of the data the temperature only changed 8 K when the sensors were flush in the end of the shock tube. The sensor temperature changed 36 K during the same time when mounted on a probe in the flow. Schlieren pictures were taken of the flow in the shock tube to further understand the shock tube environment. Contrary to ideal shock tube theory, it was discovered that the flow did not remain stagnant in the end of the shock tube after the shock reflects from the end of the shock tube. Instead, the effects of turbulence were recorded with the fiber-optic sensors, and this turbulence was also captured in the schlieren photographs. A fast-response thermocouple was used to collect data for comparison with the fiber-optic sensor, and the fiber-optic sensor was proven to have a faster response time compared to the thermocouple. When the sensors were extended 12.7 cm into the flow, the fiber-optic sensors recorded a temperature change of 143 K compared to 38 K recorded by the thermocouple during the 0.5 millisecond test. This corresponds to 22% of the change of total temperature in the air recorded by the fiber-optic sensor and only 6% recorded by the thermocouple. Put another way, the fiber-optic sensor experience a rate of temperature change equal to 2.9x105 K/s and the thermocouple changed at a rate of 0.79x105 K/s. The data recorded from the fiber-optic sensor also contained much less noise than the thermocouple data. An unsteady finite element thermal model was created using ANSYS to predict the temperature response of the sensor. Test cases with known analytical solutions were used to verify the ANSYS modeling procedures. The shock tube flow environment was also modeled with Fluent, a commercially available CFD code. Fluent was used to determine the heat transfer between the shock tube flow and the sensor. The convection film coefficient for the flow was predicted by Fluent to be 27,150 W/m2K for the front of the wafer and 13,385 W/m2K for the side. The Fluent results were used with the ANSYS model to predict the response of the fiber-optic sensor when exposed to the shock tube flow. The results from the Fluent/ANSYS model were compared to the fiber-optic measurements taken in the shock tube. It was seen that the heat flux to the sensor was slightly over-predicted by the model, and the heat losses from the wafer were also over-predicted. Since the prediction fell within the uncertainty of the measurement, it was found to be in good agreement with the measured values. (Abstract shortened by UMI.)

Fiber optic sensors; Proceedings of the Meeting, Cannes, France, November 26, 27, 1985

NASA Technical Reports Server (NTRS)

Arditty, Herve J. (Editor); Jeunhomme, Luc B. (Editor)

1986-01-01

The conference presents papers on distributed sensors and sensor networks, signal processing and detection techniques, temperature measurements, chemical sensors, and the measurement of pressure, strain, and displacements. Particular attention is given to optical fiber distributed sensors and sensor networks, tactile sensing in robotics using an optical network and Z-plane techniques, and a spontaneous Raman temperature sensor. Other topics include coherence in optical fiber gyroscopes, a high bandwidth two-phase flow void fraction fiber optic sensor, and a fiber-optic dark-field microbend sensor.

Double-layer optical fiber coating analysis in MHD flow of an elastico-viscous fluid using wet-on-wet coating process

NASA Astrophysics Data System (ADS)

Khan, Zeeshan; Islam, Saeed; Shah, Rehan Ali; Khan, Muhammad Altaf; Bonyah, Ebenezer; Jan, Bilal; Khan, Aurangzeb

Modern optical fibers require a double-layer coating on the glass fiber in order to provide protection from signal attenuation and mechanical damage. The most important plastic resins used in wires and optical fibers are plastic polyvinyl chloride (PVC) and low and high density polyethylene (LDPE/HDPE), nylon and Polysulfone. One of the most important things which affect the final product after processing is the design of the coating die. In the present study, double-layer optical fiber coating is performed using melt polymer satisfying Oldroyd 8-constant fluid model in a pressure type die with the effect of magneto-hydrodynamic (MHD). Wet-on-wet coating process is applied for double-layer optical fiber coating. The coating process in the coating die is modeled as a simple two-layer Couette flow of two immiscible fluids in an annulus with an assigned pressure gradient. Based on the assumptions of fully developed laminar and MHD flow, the Oldroyd 8-constant model of non-Newtonian fluid of two immiscible resin layers is modeled. The governing nonlinear equations are solved analytically by the new technique of Optimal Homotopy Asymptotic Method (OHAM). The convergence of the series solution is established. The results are also verified by the Adomian Decomposition Method (ADM). The effect of important parameters such as magnetic parameter Mi , the dilatant constant α , the Pseodoplastic constant β , the radii ratio δ , the pressure gradient Ω , the speed of fiber optics V , and the viscosity ratio κ on the velocity profiles, thickness of coated fiber optics, volume flow rate, and shear stress on the fiber optics are investigated. At the end the result of the present work is also compared with the experimental results already available in the literature by taking non-Newtonian parameters tends to zero.

Trapping and Propelling Microparticles at Long Range by Using an Entirely Stripped and Slightly Tapered No-Core Optical Fiber

PubMed Central

Sheu, Fang-Wen; Huang, Yen-Si

2013-01-01

A stripped no-core optical fiber with a 125 μm diameter was transformed into a symmetric and unbroken optical fiber that tapers slightly to a 45-μm-diameter waist. The laser light can be easily launched into the no-core optical fiber. The enhanced evanescent wave of the slightly tapered no-core optical fiber can attract nearby 5-μm-diameter polystyrene microparticles onto the surface of the tapered multimode optical fiber within fast flowing fluid and propel the trapped particles in the direction of the light propagation to longer delivery range than is possible using a slightly tapered telecom single-mode optical fiber. PMID:23449118

Trapping and propelling microparticles at long range by using an entirely stripped and slightly tapered no-core optical fiber.

PubMed

Sheu, Fang-Wen; Huang, Yen-Si

2013-02-28

A stripped no-core optical fiber with a 125 µm diameter was transformed into a symmetric and unbroken optical fiber that tapers slightly to a 45-µm-diameter waist. The laser light can be easily launched into the no-core optical fiber. The enhanced evanescent wave of the slightly tapered no-core optical fiber can attract nearby 5-µm-diameter polystyrene microparticles onto the surface of the tapered multimode optical fiber within fast flowing fluid and propel the trapped particles in the direction of the light propagation to longer delivery range than is possible using a slightly tapered telecom single-mode optical fiber.

Large-aperture, tapered fiber-coupled, 10-kHz particle-image velocimetry.

PubMed

Hsu, Paul S; Roy, Sukesh; Jiang, Naibo; Gord, James R

2013-02-11

We demonstrate the design and implementation of a fiber-optic beam-delivery system using a large-aperture, tapered step-index fiber for high-speed particle-image velocimetry (PIV) in turbulent combustion flows. The tapered fiber in conjunction with a diffractive-optical-element (DOE) fiber-optic coupler significantly increases the damage threshold of the fiber, enabling fiber-optic beam delivery of sufficient nanosecond, 532-nm, laser pulse energy for high-speed PIV measurements. The fiber successfully transmits 1-kHz and 10-kHz laser pulses with energies of 5.3 mJ and 2 mJ, respectively, for more than 25 min without any indication of damage. It is experimentally demonstrated that the tapered fiber possesses the high coupling efficiency (~80%) and moderate beam quality for PIV. Additionally, the nearly uniform output-beam profile exiting the fiber is ideal for PIV applications. Comparative PIV measurements are made using a conventionally (bulk-optic) delivered light sheet, and a similar order of measurement accuracy is obtained with and without fiber coupling. Effective use of fiber-coupled, 10-kHz PIV is demonstrated for instantaneous 2D velocity-field measurements in turbulent reacting flows. Proof-of-concept measurements show significant promise for the performance of fiber-coupled, high-speed PIV using a tapered optical fiber in harsh laser-diagnostic environments such as those encountered in gas-turbine test beds and the cylinder of a combustion engine.

Repetitive Immunosensor with a Fiber-Optic Device and Antibody-Coated Magnetic Beads for Semi-Continuous Monitoring of Escherichia coli O157:H7

PubMed Central

Taniguchi, Midori; Saito, Hirokazu; Mitsubayashi, Kohji

2017-01-01

A rapid and reproducible fiber-optic immunosensor for Escherichia coli O157:H7 (E. coli O157:H7) was described. The biosensor consisted of a flow cell, an optical fiber with a thin Ni layer, and a PC linked fluorometer. First, the samples with E. coli O157:H7 were incubated with magnetic beads coated with anti-E. coli O157:H7 antibodies and anti-E. coli O157:H7 antibodies labeled cyanine 5 (Cy5) to make sandwich complexes. Then the Cy5-(E. coli O157:H7)-beads were injected into a flow cell and pulled to the magnetized Ni layer on the optical fiber set in the flow cell. An excitation light (λ = 635 nm) was used to illuminate the optical fiber, and the Cy5 florescent molecules facing the optical fiber were exposed to an evanescent wave from the optical fiber. The 670 nm fluorescent light was measured using a photodiode. Finally, the magnetic intensity of the Ni layer was removed and the Cy5-E. coli O157:H7-beads were washed out for the next immunoassay. E. coli O157:H7, diluted with phosphate buffer (PB), was measured from 1 × 105 to 1 × 107 cells/mL. The total time required for an assay was less than 15 min (except for the pretreatment process) and repeating immunoassay on one optical fiber was made possible. PMID:28925937

Repetitive Immunosensor with a Fiber-Optic Device and Antibody-Coated Magnetic Beads for Semi-Continuous Monitoring of Escherichia coli O157:H7.

PubMed

Taniguchi, Midori; Saito, Hirokazu; Mitsubayashi, Kohji

2017-09-19

A rapid and reproducible fiber-optic immunosensor for Escherichia coli O157:H7 ( E. coli O157:H7) was described. The biosensor consisted of a flow cell, an optical fiber with a thin Ni layer, and a PC linked fluorometer. First, the samples with E. coli O157:H7 were incubated with magnetic beads coated with anti- E. coli O157:H7 antibodies and anti- E. coli O157:H7 antibodies labeled cyanine 5 (Cy5) to make sandwich complexes. Then the Cy5-( E. coli O157:H7)-beads were injected into a flow cell and pulled to the magnetized Ni layer on the optical fiber set in the flow cell. An excitation light (λ = 635 nm) was used to illuminate the optical fiber, and the Cy5 florescent molecules facing the optical fiber were exposed to an evanescent wave from the optical fiber. The 670 nm fluorescent light was measured using a photodiode. Finally, the magnetic intensity of the Ni layer was removed and the Cy5- E. coli O157:H7-beads were washed out for the next immunoassay. E. coli O157:H7, diluted with phosphate buffer (PB), was measured from 1 × 10⁵ to 1 × 10⁷ cells/mL. The total time required for an assay was less than 15 min (except for the pretreatment process) and repeating immunoassay on one optical fiber was made possible.

Fiber-optic system for checking the acoustical parameters of gas-turbine engine flow-through passages

NASA Astrophysics Data System (ADS)

Vinogradov, Vasiliy Y.; Morozov, Oleg G.; Nureev, Ilnur I.; Kuznetzov, Artem A.

2015-03-01

In this paper we consider the integrated approach to development of the aero-acoustical methods for diagnostics of aircraft gas-turbine engine flow-through passages by using as the base the passive fiber-optic and location technologies.

Methods and systems for detecting gas flow by photoacoustic signal generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choudhury, Niloy; Challener, William Albert

A method for the detection of a gas flowing from a location in a structure is described. A hollow-core optical fiber is placed in a position adjacent the structure. The fiber includes a sound-conductive cladding layer; and further includes at least one aperture extending into its cross-sectional diameter. A beam of pulsed, optical is transmitted into the fiber with a tunable laser. The optical energy is characterized by a wavelength that can be absorbed by the gas that flows into the fiber through the aperture. This causes a temperature fluctuation in the region of gas absorption, which in turn generatesmore » an acoustic wave in the absorption region. The acoustic wave travels through the cladding layer, and can be detected with a microphone, so as to provide the location of gas flow, based on the recorded position and movement of the acoustic wave. A related system is also described.« less

Mode coupling in 340 μm GeO2 doped core-silica clad optical fibers

NASA Astrophysics Data System (ADS)

Djordjevich, Alexandar; Savović, Svetislav

2017-03-01

The state of mode coupling in 340 μm GeO2 doped core-silica clad optical fibers is investigated in this article using the power flow equation. The coupling coefficient in this equation was first tuned such that the equation could correctly reconstruct previously reported measured output power distributions. It was found that the GeO2 doped core-silica clad optical fiber showed stronger mode coupling than both, glass and popular plastic optical fibers. Consequently, the equilibrium as well as steady state mode distributions were achieved at shorter fiber lengths in GeO2 doped core-silica clad optical fibers.

Fiber optic distributed temperature sensor mapping of a jet-mixing flow field

DOE PAGES

Lomperski, Stephen; Gerardi, Craig; Pointer, William David

2015-03-04

In this paper, we introduce the use of a Rayleigh backscatter-based distributed fiber optic sensor to map the temperature field in air flow for a thermal fatigue application. The experiment involves a pair of air jets at 22 and 70°C discharging from 136 mm hexagonal channels into a 1 × 1 × 1.7 m tank at atmospheric pressure. A 40 m-long, Φ155 µm fiber optic sensor was wound back and forth across the tank midplane to form 16 horizontal measurement sections with a vertical spacing of 51 mm. This configuration generated a 2D temperature map with 2800 data points overmore » a 0.76 × 1.7 m plane. Fiber optic sensor readings were combined with PIV and infrared measurements to relate flow field characteristics to the thermal signature of the tank lid. The paper includes sensor stability data and notes issues encountered using the distributed temperature sensor in a flow field. In conclusion, sensors are sensitive to strain and humidity, and so accuracy relies upon strict control of both.« less

Fiber optic distributed temperature sensor mapping of a jet-mixing flow field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lomperski, Stephen; Gerardi, Craig; Pointer, William David

In this paper, we introduce the use of a Rayleigh backscatter-based distributed fiber optic sensor to map the temperature field in air flow for a thermal fatigue application. The experiment involves a pair of air jets at 22 and 70°C discharging from 136 mm hexagonal channels into a 1 × 1 × 1.7 m tank at atmospheric pressure. A 40 m-long, Φ155 µm fiber optic sensor was wound back and forth across the tank midplane to form 16 horizontal measurement sections with a vertical spacing of 51 mm. This configuration generated a 2D temperature map with 2800 data points overmore » a 0.76 × 1.7 m plane. Fiber optic sensor readings were combined with PIV and infrared measurements to relate flow field characteristics to the thermal signature of the tank lid. The paper includes sensor stability data and notes issues encountered using the distributed temperature sensor in a flow field. In conclusion, sensors are sensitive to strain and humidity, and so accuracy relies upon strict control of both.« less

Fiber optic sensor for measurement of pressure fluctuations at high temperatures

NASA Technical Reports Server (NTRS)

Zuckerwar, Allan J.; Cuomo, Frank W.

1989-01-01

A fiber-optic sensor, based on the principle of the fiber-optic lever, is described which features small size, extended bandwidth, and capability to operate at high temeratures, as required for measurements in hypersonic flow. The principle of operation, design features peculiar to the intended application, and expected performance at high temperatures are described.

Applications for fiber optic sensing in the upstream oil and gas industry

NASA Astrophysics Data System (ADS)

Baldwin, Chris S.

2015-05-01

Fiber optic sensing has been used in an increasing number of applications in the upstream oil and gas industry over the past 20 years. In some cases, fiber optic sensing is providing measurements where traditional measurement technologies could not. This paper will provide a general overview of these applications and describe how the use of fiber optic sensing is enabling these applications. Technologies such as Bragg gratings, distributed temperature and acoustic sensing, interferometric sensing, and Brillouin scattering will be discussed. Applications for optic sensing include a range of possibilities from a single pressure measurement point in the wellbore to multizone pressure and flow monitoring. Some applications make use of fully distributed measurements including thermal profiling of the well. Outside of the wellbore, fiber optic sensors are used in applications for flowline and pipeline monitoring and for riser integrity monitoring. Applications to be described in this paper include in-flow profiling, well integrity, production monitoring, and steam chamber growth. These applications will cover well types such as injectors, producers, hydraulic fracturing, and thermal recovery. Many of these applications use the measurements provided by fiber optic sensing to improve enhanced oil recovery operations. The growing use of fiber optic sensors is providing improved measurement capabilities leading to the generation of actionable data for enhanced production optimization. This not only increases the recovered amount of production fluids but can also enhance wellbore integrity and safety.

Optofluidic microvalve-on-a-chip with a surface plasmon-enhanced fiber optic microheater

PubMed Central

Zhang, Zhijian; Kusimo, Abisola; Yu, Miao

2014-01-01

We present an optofluidic microvalve utilizing an embedded, surface plasmon-enhanced fiber optic microheater. The fiber optic microheater is formed by depositing a titanium thin film on the roughened end-face of a silica optical fiber that serves as a waveguide to deliver laser light to the titanium film. The nanoscale roughness at the titanium-silica interface enables strong light absorption enhancement in the titanium film through excitation of localized surface plasmons as well as facilitates bubble nucleation. Our experimental results show that due to the unique design of the fiber optic heater, the threshold laser power required to generate a bubble is greatly reduced and the bubble growth rate is significantly increased. By using the microvalve, stable vapor bubble generation in the microchannel is demonstrated, which does not require complex optical focusing and alignment. The generated vapor bubble is shown to successfully block a liquid flow channel with a size of 125 μm × 125 μm and a flow rate of ∼10 μl/min at ∼120 mW laser power. PMID:25538813

Gas-phase optical fiber photocatalytic reactors for indoor air application: a preliminary study on performance indicators

NASA Astrophysics Data System (ADS)

Palmiste, Ü.; Voll, H.

2017-10-01

The development of advanced air cleaning technologies aims to reduce building energy consumption by reduction of outdoor air flow rates while keeping the indoor air quality at an acceptable level by air cleaning. Photocatalytic oxidation is an emerging technology for gas-phase air cleaning that can be applied in a standalone unit or a subsystem of a building mechanical ventilation system. Quantitative information on photocatalytic reactor performance is required to evaluate the technical and economic viability of the advanced air cleaning by PCO technology as an energy conservation measure in a building air conditioning system. Photocatalytic reactors applying optical fibers as light guide or photocatalyst coating support have been reported as an approach to address the current light utilization problems and thus, improve the overall efficiency. The aim of the paper is to present a preliminary evaluation on continuous flow optical fiber photocatalytic reactors based on performance indicators commonly applied for air cleaners. Based on experimental data, monolith-type optical fiber reactor performance surpasses annular-type optical fiber reactors in single-pass removal efficiency, clean air delivery rate and operating cost efficiency.

High speed, wide velocity dynamic range Doppler optical coherence tomography (Part III): in vivo endoscopic imaging of blood flow in the rat and human gastrointestinal tracts

NASA Astrophysics Data System (ADS)

Yang, Victor X. D.; Gordon, Maggie L.; Tang, Shou-Jiang; Marcon, Norman E.; Gardiner, Geoffrey; Qi, Bing; Bisland, Stuart; Seng-Yue, Emily; Lo, Stewart; Pekar, Julius; Wilson, Brian C.; Vitkin, I. Alex

2003-09-01

We previously described a fiber based Doppler optical coherence tomography system [1] capable of imaging embryo cardiac blood flow at 4~16 frames per second with wide velocity dynamic range [2]. Coupling this system to a linear scanning fiber optical catheter design that minimizes friction and vibrations, we report here the initial results of in vivo endoscopic Doppler optical coherence tomography (EDOCT) imaging in normal rat and human esophagus. Microvascular flow in blood vessels less than 100 µm diameter was detected using a combination of color-Doppler and velocity variance imaging modes, during clinical endoscopy using a mobile EDOCT system.

Lab-on-fiber electrophoretic trace mixture separating and detecting an optofluidic device based on a microstructured optical fiber.

PubMed

Yang, Xinghua; Guo, Xiaohui; Li, Song; Kong, Depeng; Liu, Zhihai; Yang, Jun; Yuan, Libo

2016-04-15

We report an in-fiber integrated electrophoretic trace mixture separating and detecting an optofluidic optical fiber sensor based on a specially designed optical fiber. In this design, rapid in situ separation and simultaneous detection of mixed analytes can be realized under electro-osmotic flow in the microstructured optical fiber. To visually display the in-fiber separating and detecting process, two common fluorescent indicators are adopted as the optofluidic analytes in the optical fiber. Results show that a trace amount of the mixture (0.15 μL) can be completely separated within 3.5 min under a high voltage of 5 kV. Simultaneously, the distributed information of the separated analytes in the optical fiber can be clearly obtained by scanning along the optical fiber using a 355 nm laser. The emission from the analytes can be efficiently coupled into the inner core and guides to the remote end of the optical fiber. In addition, the thin cladding around the inner core in the optical fiber can prevent the fluorescent cross talk between the analytes in this design. Compared to previous optical fiber optofluidic devices, this device first realizes simultaneously separating treatment and the detection of the mixed samples in an optical fiber. Significantly, such an in-fiber integrated separating and detecting optofluidic device can find wide applications in various analysis fields involves mixed samples, such as biology, chemistry, and environment.

Development of Metal Oxide Nanostructure-based Optical Sensors for Fossil Fuel Derived Gases Measurement at High Temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Kevin P.

2015-02-13

This final technical report details research works performed supported by a Department of Energy grant (DE-FE0003859), which was awarded under the University Coal Research Program administrated by National Energy Technology Laboratory. This research program studied high temperature fiber sensor for harsh environment applications. It developed two fiber optical sensor platform technology including regenerative fiber Bragg grating sensors and distributed fiber optical sensing based on Rayleigh backscattering optical frequency domain reflectometry. Through the studies of chemical and thermal regenerative techniques for fiber Bragg grating (FBG) fabrication, high-temperature stable FBG sensors were successfully developed and fabricated in air-hole microstructured fibers, high-attenuation fibers,more » rare-earth doped fibers, and standard telecommunication fibers. By optimizing the laser processing and thermal annealing procedures, fiber grating sensors with stable performance up to 1100°C have been developed. Using these temperature-stable FBG gratings as sensor platform, fiber optical flow, temperature, pressure, and chemical sensors have been developed to operate at high temperatures up to 800°C. Through the integration of on-fiber functional coating, the use of application-specific air-hole microstructural fiber, and application of active fiber sensing scheme, distributed fiber sensor for temperature, pressure, flow, liquid level, and chemical sensing have been demonstrated with high spatial resolution (1-cm or better) with wide temperature ranges. These include the demonstration of 1) liquid level sensing from 77K to the room temperature, pressure/temperature sensing from the room temperature to 800C and from the 15psi to 2000 psi, and hydrogen concentration measurement from 0.2% to 10% with temperature ranges from the room temperature to 700°C. Optical sensors developed by this program has broken several technical records including flow sensors with the highest operation temperature up to 750°C, first distributed chemical measurements at the record high temperature up to 700°C, first distributed pressure measurement at the record high temperature up to 800°C, and the fiber laser sensors with the record high operation temperature up to 700°C. The research performed by this program dramatically expand the functionality, adaptability, and applicability of distributed fiber optical sensors with potential applications in a number of high-temperature energy systems such as fossil-fuel power generation, high-temperature fuel cell applications, and potential for nuclear energy systems.« less

One-Dimensional Scanning Approach to Shock Sensing

NASA Technical Reports Server (NTRS)

Tokars, Roger; Adamovsky, Girgory; Floyd, Bertram

2009-01-01

Measurement tools for high speed air flow are sought both in industry and academia. Particular interest is shown in air flows that exhibit aerodynamic shocks. Shocks are accompanied by sudden changes in density, pressure, and temperature. Optical detection and characterization of such shocks can be difficult because the medium is normally transparent air. A variety of techniques to analyze these flows are available, but they often require large windows and optical components as in the case of Schlieren measurements and/or large operating powers which precludes their use for in-flight monitoring and applications. The one-dimensional scanning approach in this work is a compact low power technique that can be used to non-intrusively detect shocks. The shock is detected by analyzing the optical pattern generated by a small diameter laser beam as it passes through the shock. The optical properties of a shock result in diffraction and spreading of the beam as well as interference fringes. To investigate the feasibility of this technique a shock is simulated by a 426 m diameter optical fiber. Analysis of results revealed a direct correlation between the optical fiber or shock location and the beam s diffraction pattern. A plot of the width of the diffraction pattern vs. optical fiber location reveals that the width of the diffraction pattern was maximized when the laser beam is directed at the center of the optical fiber. This work indicates that the one-dimensional scanning approach may be able to determine the location of an actual shock. Near and far field effects associated with a small diameter laser beam striking an optical fiber used as a simulated shock are investigated allowing a proper one-dimensional scanning beam technique.

Monolithic fiber optic sensor assembly

DOEpatents

Sanders, Scott

2015-02-10

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

A high sensitivity fiber optic macro-bend based gas flow rate transducer for low flow rates: Theory, working principle, and static calibration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schena, Emiliano; Saccomandi, Paola; Silvestri, Sergio

2013-02-15

A novel fiber optic macro-bend based gas flowmeter for low flow rates is presented. Theoretical analysis of the sensor working principle, design, and static calibration were performed. The measuring system consists of: an optical fiber, a light emitting diode (LED), a Quadrant position sensitive Detector (QD), and an analog electronic circuit for signal processing. The fiber tip undergoes a deflection in the flow, acting like a cantilever. The consequent displacement of light spot center is monitored by the QD generating four unbalanced photocurrents which are function of fiber tip position. The analog electronic circuit processes the photocurrents providing voltage signalmore » proportional to light spot position. A circular target was placed on the fiber in order to increase the sensing surface. Sensor, tested in the measurement range up to 10 l min{sup -1}, shows a discrimination threshold of 2 l min{sup -1}, extremely low fluid dynamic resistance (0.17 Pa min l{sup -1}), and high sensitivity, also at low flow rates (i.e., 33 mV min l{sup -1} up to 4 l min{sup -1} and 98 mV min l{sup -1} from 4 l min{sup -1} up to 10 l min{sup -1}). Experimental results agree with the theoretical predictions. The high sensitivity, along with the reduced dimension and negligible pressure drop, makes the proposed transducer suitable for medical applications in neonatal ventilation.« less

OPTICAL FIBER SENSOR TECHNOLOGIES FOR EFFICIENT AND ECONOMICAL OIL RECOVERY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kristie Cooper; Gary Pickrell; Anbo Wang

2003-04-01

This report summarizes technical progress over the fourth year of the ''Optical Fiber Sensor Technologies for Efficient and Economical Oil Recovery'' program, funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. During the reporting period, research efforts under the program were focused on the development and evaluation of the fiber optic flow sensor system, and field testing in Tulsa, OK and the second field test of the pressure and temperature sensors in Coalinga, CA. The feasibilitymore » of a self-compensating fiber optic flow sensor based on a cantilever beam and interferometer for real-time flow rate measurements in the fluid filled pipes of oil field was clearly demonstrated. In addition, field testing of the pressure and temperature sensors deployed downhole continued. These accomplishments are summarized here: (1) Theoretical analysis and simulations were performed to ensure performance of the design. (2) The sensor fabrication and packaging techniques were investigated and improved. (3) Prototype flow sensors were fabricated based on the fabrication experience of hundreds of test sensors. (4) A lab-scale flow testing system was constructed and used for sensor evaluation. (5) Field-testing was performed in both the indoor and outdoor flow testing facility at the University of Tulsa, OK. (6) Testing of a multimode white light pressure and temperature sensor system continued at the oil site of Chevron/Texaco Company (Coalinga CA).« less

Optical Sensor of Thermal Gas Flow Based on Fiber Bragg Grating.

PubMed

Jiang, Xu; Wang, Keda; Li, Junqing; Zhan, Hui; Song, Zhenan; Che, Guohang; Lyu, Guohui

2017-02-15

This paper aims at solving the problem of explosion proof in measurement of thermal gas flow using electronic sensor by presenting a new type of flow sensor by optical fiber heating. A measuring unit based on fiber Bragg grating (FBG) for fluid temperature and a unit for heat dissipation are designed to replace the traditional electronic sensors. The light in C band from the amplified spontaneous emission (ASE) light source is split, with one part used to heat the absorbing coating and the other part used in the signal processing unit. In the heating unit, an absorbing coating is introduced to replace the traditional resistance heating module to minimize the risk of explosion. The measurement results demonstrate a fine consistency between the flow and temperature difference in simulation. The method to enhance the measurement resolution of flow is also discussed.

OPTICAL FIBER SENSOR TECHNOLOGIES FOR EFFICIENT AND ECONOMICAL OIL RECOVERY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anbo Wang; Kristie L. Cooper; Gary R. Pickrell

2003-06-01

Efficient recovery of petroleum reserves from existing oil wells has been proven to be difficult due to the lack of robust instrumentation that can accurately and reliably monitor processes in the downhole environment. Commercially available sensors for measurement of pressure, temperature, and fluid flow exhibit shortened lifetimes in the harsh downhole conditions, which are characterized by high pressures (up to 20 kpsi), temperatures up to 250 C, and exposure to chemically reactive fluids. Development of robust sensors that deliver continuous, real-time data on reservoir performance and petroleum flow pathways will facilitate application of advanced recovery technologies, including horizontal and multilateralmore » wells. This is the final report for the four-year program ''Optical Fiber Sensor Technologies for Efficient and Economical Oil Recovery'', funded by the National Petroleum Technology Office of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech from October 1, 1999 to March 31, 2003. The main objective of this research program was to develop cost-effective, reliable optical fiber sensor instrumentation for real-time monitoring of various key parameters crucial to efficient and economical oil production. During the program, optical fiber sensors were demonstrated for the measurement of temperature, pressure, flow, and acoustic waves, including three successful field tests in the Chevron/Texaco oil fields in Coalinga, California, and at the world-class oil flow simulation facilities in Tulsa, Oklahoma. Research efforts included the design and fabrication of sensor probes, development of signal processing algorithms, construction of test systems, development and testing of strategies for the protection of optical fibers and sensors in the downhole environment, development of remote monitoring capabilities allowing real-time monitoring of the field test data from virtually anywhere in the world, and development of novel data processing techniques. Comprehensive testing was performed to systematically evaluate the performance of the fiber optic sensor systems in both lab and field environments.« less

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

PubMed

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

2013-03-01

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

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

NASA Astrophysics Data System (ADS)

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

2013-03-01

In this work, a simple and low-cost air flow sensor, based on a novel fiber-optic sensing technique has been developed for monitoring air flows rates supplied by a neonatal ventilator to support infants in intensive care units. The device is based on a fiber optic sensing technique allowing (a) the immunity to light intensity variations independent by measurand and (b) the reduction of typical shortcomings affecting all biomedical fields (electromagnetic interference and patient electrical safety). The sensing principle is based on the measurement of transversal displacement of an emitting fiber-optic cantilever due to action of air flow acting on it; the fiber tip displacement is measured by means of a photodiode linear array, placed in front of the entrance face of the emitting optical fiber in order to detect its light intensity profile. As the measurement system is based on a detection of the illumination pattern, and not on an intensity modulation technique, it results less sensitive to light intensity fluctuation independent by measurand than intensity-based sensors. The considered technique is here adopted in order to develop two different configurations for an air flow sensor suitable for the measurement of air flow rates typically occurring during mechanical ventilation of newborns: a mono-directional and a bi-directional transducer have been proposed. A mathematical model for the air flow sensor is here proposed and a static calibration of two different arrangements has been performed: a measurement range up to 3.00 × 10-4 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 δQ 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.

Fiber Optic Temperature Sensors in TPS: Arc Jet Model Design & Testing

NASA Technical Reports Server (NTRS)

Black, Richard; Feldman, Jay; Ellerby, Donald; Monk, Joshua; Moslehi, Behzad; Oblea, Levy; Switzer, Matthew

2017-01-01

Techniques for using fiber optics with Fiber Bragg Gratings (FBGs) have been developed by IFOS Corp. for use in thermal protection systems (TPS) on spacecraft heat shield materials through NASA Phase 1 and 2 SBIR efforts and have been further improved in a recent collaboration between IFOS and NASA that will be described here. Fiber optic temperature sensors offer several potential advantages over traditional thermocouple sensors including a) multiplexing many sensors in a single fiber to increase sensor density in a given array or to provide spatial resolution, b) improved thermal property match between sensor and TPS to reduce heat flow disruption, c) lack of electrical conductivity.

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

PubMed

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

2014-06-21

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

Fiber Optic Sensors for Health Monitoring of Morphing Aircraft

NASA Technical Reports Server (NTRS)

Brown, Timothy; Wood, Karen; Childers, Brooks; Cano, Roberto; Jensen, Brian; Rogowski, Robert

2001-01-01

Fiber optic sensors are being developed for health monitoring of future aircraft. Aircraft health monitoring involves the use of strain, temperature, vibration and chemical sensors. These sensors will measure load and vibration signatures that will be used to infer structural integrity. Sine the aircraft morphing program assumes that future aircraft will be aerodynamically reconfigurable there is also a requirement for pressure, flow and shape sensors. In some cases a single fiber may be used for measuring several different parameters. The objective of the current program is to develop techniques for using optical fibers to monitor composite cure in real time during manufacture and to monitor in-service structural integrity of the composite structure. Graphite-epoxy panels were fabricated with integrated optical fibers of various types. The panels were mechanically and thermally tested to evaluate composite strength and sensor durability. Finally the performance of the fiber optic sensors was determined. Experimental results are presented evaluating the performance of embedded and surface mounted optical fibers for measuring strain, temperature and chemical composition. The performance of the fiber optic sensors was determined by direct comparison with results from more conventional instrumentation. The facilities for fabricating optical fiber and associated sensors and methods of demodulating Bragg gratings for strain measurement will be described.

Supersonic Flow Field Investigation Using a Fiber-optic based Doppler Global Velocimeter

NASA Technical Reports Server (NTRS)

Meyers, James F.; Lee, Joseph W.; Fletcher, Mark T.; Cavone, Angelo A.; AscencionGuerreroViramontes, J.

2006-01-01

A three-component fiber-optic based Doppler Global Velocimeter was constructed, evaluated and used to measure shock structures about a low-sonic boom model in a Mach 2 flow. The system was designed to have maximum flexibility in its ability to measure flows with restricted optical access and in various facilities. System layout is described along with techniques developed for production supersonic testing. System evaluation in the Unitary Plan Wind Tunnel showed a common acceptance angle of f4 among the three views with velocity measurement resolutions comparable with free-space systems. Flow field measurements of shock structures above a flat plate with an attached ellipsoid-cylinder store and a low-sonic boom model are presented to demonstrate the capabilities of the system during production testing.

Investigation on Dynamic Calibration for an Optical-Fiber Solids Concentration Probe in Gas-Solid Two-Phase Flows

PubMed Central

Xu, Guiling; Liang, Cai; Chen, Xiaoping; Liu, Daoyin; Xu, Pan; Shen, Liu; Zhao, Changsui

2013-01-01

This paper presents a review and analysis of the research that has been carried out on dynamic calibration for optical-fiber solids concentration probes. An introduction to the optical-fiber solids concentration probe was given. Different calibration methods of optical-fiber solids concentration probes reported in the literature were reviewed. In addition, a reflection-type optical-fiber solids concentration probe was uniquely calibrated at nearly full range of the solids concentration from 0 to packed bed concentration. The effects of particle properties (particle size, sphericity and color) on the calibration results were comprehensively investigated. The results show that the output voltage has a tendency to increase with the decreasing particle size, and the effect of particle color on calibration result is more predominant than that of sphericity. PMID:23867745

Civil infrastructure monitoring for IVHS using optical fiber sensors

NASA Astrophysics Data System (ADS)

de Vries, Marten J.; Arya, Vivek; Grinder, C. R.; Murphy, Kent A.; Claus, Richard O.

1995-01-01

8Early deployment of Intelligent Vehicle Highway Systems would necessitate the internal instrumentation of infrastructure for emergency preparedness. Existing quantitative analysis and visual analysis techniques are time consuming, cost prohibitive, and are often unreliable. Fiber optic sensors are rapidly replacing conventional instrumentation because of their small size, light weight, immunity to electromagnetic interference, and extremely high information carrying capability. In this paper research on novel optical fiber sensing techniques for health monitoring of civil infrastructure such as highways and bridges is reported. Design, fabrication, and implementation of fiber optic sensor configurations used for measurements of strain are discussed. Results from field tests conducted to demonstrate the effectiveness of fiber sensors at determining quantitative strain vector components near crack locations in bridges are presented. Emerging applications of fiber sensors for vehicle flow, vehicle speed, and weigh-in-motion measurements are also discussed.

Optical fiber sensor for breathing diagnostics

NASA Astrophysics Data System (ADS)

Claus, Richard O.; Distler, T.; Mecham, J. B.; Davis, B.; Arregui, F. J.; Matias, I. R.

2004-06-01

We report improvements of an optical fiber-based humidity sensor to the problem of breathing diagnostics. The sensor is fabricated by molecularly self-assembling selected polymers and functionalized inorganic nanoclusters into multilayered optical thin films on the cleaved and polished flat end of a singlemode optical fiber. Recent work has studied the synthesis process and the fundamental mechanisms responsible for the change in optical reflection from such a multicomponent film that occurs as a function of humidity and various chemicals. We briefly review that prior work as a way to introduce more recent developments. The paper then discusses the application of these humidity sensors to the analysis of air flow associated with breathing [1]. We have designed the sensor thin film materials to enable the detection of relative humidity over a wide range, from approximately 5 to 95%, and for response times as short as several microseconds. This fast response time allows the near real-time analysis of air flow and water vapor transport during a single breath, with the advantage of very small size. The use of multiple sensors spaced a known distance apart allows the measurement of flow velocity, and recent work indicates a variation in sensor response versus coating thickness.

All-optical fiber anemometer based on laser heated fiber Bragg gratings.

PubMed

Gao, Shaorui; Zhang, A Ping; Tam, Hwa-Yaw; Cho, L H; Lu, Chao

2011-05-23

A fiber-optic anemometer based on fiber Bragg gratings (FBGs) is presented. A short section of cobalt-doped fiber was utilized to make a fiber-based "hot wire" for wind speed measurement. Fiber Bragg gratings (FBGs) were fabricated in the cobalt-doped fiber using 193 nm laser pulses to serve as localized temperature sensors. A miniature all-optical fiber anemometer is constructed by using two FBGs to determine the dynamic thermal equilibrium between the laser heating and air flow cooling through monitoring the FBGs' central wavelengths. It was demonstrated that the sensitivity of the sensor can be adjusted through the power of pump laser or the coating on the FBG. Experimental results reveal that the proposed FBG-based anemometer exhibits very good performance for wind speed measurement. The resolution of the FBG-based anemometer is about 0.012 m/s for wind speed range between 2.0 m/s and 8.0 m/s.

Optical fiber sensors for breathing diagnostics

NASA Astrophysics Data System (ADS)

Chen, Q.; Claus, Richard O.; Mecham, Jeffrey B.; Vercellino, M.; Arregui, Francisco J.; Matias, Ignacio R.

2002-03-01

We report the application of an optical fiber-based humidity sensor to the problem of breathing diagnostics. The sensor is fabricated by molecularly self-assembling selected polymers and functionalized inorganic nanoclusters into multilayered optical thin films on the cleaved and polished flat end of a singlemode optical fiber. Prior work has studied the synthesis process and the fundamental mechanisms responsible for the change in optical reflection from the film that occurs as a function of humidity. We will briefly review that prior work as a way to introduce more recent developments. This paper will then discuss the application of these sensors to the analysis of air flow. We have designed the sensor thin film materials for the detection of relative humidity over a wide range, from approximately 10 to 95%, and for response times as short as several tens of milliseconds. This very fast response time allows the near real-time analysis of air flow and humidity during a single breath, with the advantage of very small size.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2013-03-15

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;more » 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.« less

High-performance parallel interface to synchronous optical network gateway

DOEpatents

St. John, Wallace B.; DuBois, David H.

1996-01-01

A system of sending and receiving gateways interconnects high speed data interfaces, e.g., HIPPI interfaces, through fiber optic links, e.g., a SONET network. An electronic stripe distributor distributes bytes of data from a first interface at the sending gateway onto parallel fiber optics of the fiber optic link to form transmitted data. An electronic stripe collector receives the transmitted data on the parallel fiber optics and reforms the data into a format effective for input to a second interface at the receiving gateway. Preferably, an error correcting syndrome is constructed at the sending gateway and sent with a data frame so that transmission errors can be detected and corrected in a real-time basis. Since the high speed data interface operates faster than any of the fiber optic links the transmission rate must be adapted to match the available number of fiber optic links so the sending and receiving gateways monitor the availability of fiber links and adjust the data throughput accordingly. In another aspect, the receiving gateway must have sufficient available buffer capacity to accept an incoming data frame. A credit-based flow control system provides for continuously updating the sending gateway on the available buffer capacity at the receiving gateway.

Fiber optic liquid mass flow sensor and method

NASA Technical Reports Server (NTRS)

Korman, Valentin (Inventor); Gregory, Don Allen (Inventor); Wiley, John T. (Inventor); Pedersen, Kevin W. (Inventor)

2010-01-01

A method and apparatus are provided for sensing the mass flow rate of a fluid flowing through a pipe. A light beam containing plural individual wavelengths is projected from one side of the pipe across the width of the pipe so as to pass through the fluid under test. Fiber optic couplers located at least two positions on the opposite side of the pipe are used to detect the light beam. A determination is then made of the relative strengths of the light beam for each wavelength at the at least two positions and based at least in part on these relative strengths, the mass flow rate of the fluid is determined.

Decreasing diameter fluctuation of polymer optical fiber with optimized drawing conditions

NASA Astrophysics Data System (ADS)

Çetinkaya, Onur; Wojcik, Grzegorz; Mergo, Pawel

2018-05-01

The diameter fluctuations of poly(methyl methacrylate) based polymer optical fibers, during drawing processes, have been comprehensively studied. In this study, several drawing parameters were selected for investigation; such as drawing tensions, preform diameters, preform feeding speeds, and argon flows. Varied drawing tensions were used to draw fibers, while other parameters were maintained at constant. At a later stage in the process, micro-structured polymer optical fibers were drawn under optimized drawing conditions. Fiber diameter deviations were reduced to 2.2%, when a 0.2 N drawing tension was employed during the drawing process. Higher drawing tensions led to higher diameter fluctuations. The Young’s modulus of fibers drawn with different tensions was also measured. Our results showed that fiber elasticity increased as drawing tensions decreased. The inhomogeneity of fibers was also determined by comparing the deviation of Young’s modulus.

Fiber optic fluid detector

DOEpatents

Angel, S.M.

1987-02-27

Particular gases or liquids are detected with a fiber optic element having a cladding or coating of a material 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 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. 10 figs.

Microfluidic Flows and Heat Transfer and Their Influence on Optical Modes in Microstructure Fibers

PubMed Central

Davies, Edward; Christodoulides, Paul; Florides, George; Kalli, Kyriacos

2014-01-01

A finite element analysis (FEA) model has been constructed to predict the thermo-fluidic and optical properties of a microstructure optical fiber (MOF) accounting for changes in external temperature, input water velocity and optical fiber geometry. Modeling a water laminar flow within a water channel has shown that the steady-state temperature is dependent on the water channel radius while independent of the input velocity. There is a critical channel radius below which the steady-state temperature of the water channel is constant, while above, the temperature decreases. However, the distance required to reach steady state within the water channel is dependent on both the input velocity and the channel radius. The MOF has been found capable of supporting multiple modes. Despite the large thermo-optic coefficient of water, the bound modes’ response to temperature was dominated by the thermo-optic coefficient of glass. This is attributed to the majority of the light being confined within the glass, which increased with increasing external temperature due to a larger difference in the refractive index between the glass core and the water channel. PMID:28788263

An integrated micro-volume fiber-optic sensor for oxygen determination in exhaled breath based on iridium(III) complexes immobilized in fluorinated xerogels.

PubMed

Xiong, Yan; Ye, Zhongbin; Xu, Jing; Zhu, Yuanqiang; Chen, Chen; Guan, Yafeng

2013-03-21

A novel integrated fiber-optic sensor with micro detection volume is developed and evaluated for O(2) determination on a breath-by-breath basis in human health monitoring applications. The sensing element was fabricated by dip-coating an uncladded optical fiber with [Ir(piq)(2)(acac)]-doped hybrid fluorinated ORMOSIL (organically modified silicate) film, which was prepared from 3,3,3-trifluoropropyltrimethoxysilane (TFP-TriMOS) and n-propyltrimethoxysilane (n-propyl-TriMOS). The sensor was then constructed by inserting the prepared optical fiber into a transparent capillary. A microchannel formed between the optical fiber and the capillary inner wall acted as a flow cell for the sample flowing through. The evanescent wave (EW) field produced on the fiber core surface can excite the O(2)-sensitive fluorophores of [Ir(piq)(2)(acac)] to produce emission fluorescence. O(2) can be sensed by its quenching effect on the emission fluorescence intensity. Spectroscopic properties have been characterized by FTIR and fluorescence measurements. Stern-Volmer and Demas models were both employed to analyse the sensor sensitivity, which is 13.0 with the LOD = 0.009% (3σ) and the response time is about 1 s. By integrating the sensing and detection elements on the optical fiber, the novel configuration showed advantages of easy fabrication and low cost. Parameters of sensitivity, response time, repeatability, humidity effect and temperature effect were discussed in detail. The proposed sensor showed potential for practical in-breath O(2) analysis application due to its advantages of easy fabrication, low cost, fast response, excellent hydrophobicity, negligible temperature interference and suitable sensitivity.

Photoacoustic removal of occlusions from blood vessels

DOEpatents

Visuri, Steven R.; Da Silva, Luiz B.; Celliers, Peter M.; London, Richard A.; Maitland, IV, Duncan J.; Esch, Victor C.

2002-01-01

Partial or total occlusions of fluid passages within the human body are removed by positioning an array of optical fibers in the passage and directing treatment radiation pulses along the fibers, one at a time, to generate a shock wave and hydrodynamics flows that strike and emulsify the occlusions. A preferred application is the removal of blood clots (thrombin and embolic) from small cerebral vessels to reverse the effects of an ischemic stroke. The operating parameters and techniques are chosen to minimize the amount of heating of the fragile cerebral vessel walls occurring during this photo acoustic treatment. One such technique is the optical monitoring of the existence of hydrodynamics flow generating vapor bubbles when they are expected to occur and stopping the heat generating pulses propagated along an optical fiber that is not generating such bubbles.

Fiber-Based Measurement of Bow-Shock Spectra for Reentry Flight Testing

NASA Technical Reports Server (NTRS)

Schott, Timothy D.; Herring, Gregory C.; Munk, Michelle M.; Grinstead, Jay H.; Prabbu, Dinesh K.

2010-01-01

We demonstrated a fiber-based approach for obtaining optical spectra of a glowing bow shock in a high-enthalpy air flow. The work was performed in a ground test with the NASA Ames Aerodynamic Heating Facility (AHF) that is used for atmospheric reentry simulation. The method uses a commercial fiber optic that is embedded in the nose of an ablating bluntbody model and provides a line-of-sight view in the streamwise direction - directly upstream into the hot post-shock gas flow. Both phenolic impregnated carbon ablator (PICA) and phenolic carbon (PhenCarb 28) materials were used as thermal protection systems. Results show that the fibers survive the intense heat and operate sufficiently well during the first several seconds of a typical AHF run (20 MJ/kg). This approach allowed the acquisition of optical spectra, enabling a Boltzmann-based electronic excitation temperature measurement from Cu atom impurities (averaged over a line-of-sight through the gas cap, with a 0.04 sec integration time).

Preliminary design of land displacement-optical fiber sensor and analysis of observation during laboratory and field test

NASA Astrophysics Data System (ADS)

Bayuwati, Dwi; Waluyo, Tomi B.; Widiyatmoko, Bambang

2015-01-01

An optical fiber optic sensor for detecting land displacement is discussed in this paper. The sensor system consists of a laser at wavelength 1.3 um, optical fiber coupler, optical fiber as sensor and light transmitting media, PIN photodiodedetector system, data logger and personal computer. Sensor was made from a curved optical fiber with diameter 35 mm, which will be changed into a heart-shape fiber if it is pulled. The heart-shape fiber sensor is the modification of the earlier displacement fiber sensor model which was in an ellipse form. Light to and from the optical fiber sensor was transmitted into a length of a multi core, single mode optical fiber cable. The scheme of the optical displacement sensor system has been described here. Characterization in the laboratory has been done by applying a series of pulling mechanism, on the heart-shape fiber sensor; which represents the land displacement process. Characterization in the field was carried out by mounting the sensor system on a scaled-down model of a land slope and artificially reproducing the landslide process using a steady-flow of artificial rainfall as the trigger. The voltage sensor output was recorded during the artificial landslide process. The displacement occurence can be indicated from the declining of the sensor signal received by the detector while the reference signal is steady. Characterization in the laboratory resulted in the performance of the optical fiber land displacement, namely, sensitivity 0.027(mV/mV)/mm, resolution 0.37 mm and measurement range 30 mm; compared with earlier optical fiber sensor performance with similar sensitivity and resolution which works only in 8 mm displacement range. Based on the experiment of landslides simulation in the field, we can define a critical condition in the real situation before landslides occurence to take any measures to prevent more casualties and losses.

High-performance parallel interface to synchronous optical network gateway

DOEpatents

St. John, W.B.; DuBois, D.H.

1996-12-03

Disclosed is a system of sending and receiving gateways interconnects high speed data interfaces, e.g., HIPPI interfaces, through fiber optic links, e.g., a SONET network. An electronic stripe distributor distributes bytes of data from a first interface at the sending gateway onto parallel fiber optics of the fiber optic link to form transmitted data. An electronic stripe collector receives the transmitted data on the parallel fiber optics and reforms the data into a format effective for input to a second interface at the receiving gateway. Preferably, an error correcting syndrome is constructed at the sending gateway and sent with a data frame so that transmission errors can be detected and corrected in a real-time basis. Since the high speed data interface operates faster than any of the fiber optic links the transmission rate must be adapted to match the available number of fiber optic links so the sending and receiving gateways monitor the availability of fiber links and adjust the data throughput accordingly. In another aspect, the receiving gateway must have sufficient available buffer capacity to accept an incoming data frame. A credit-based flow control system provides for continuously updating the sending gateway on the available buffer capacity at the receiving gateway. 7 figs.

Optical fiber sensor based on surface plasmon resonance for rapid detection of avian influenza virus subtype H6: Initial studies.

PubMed

Zhao, Xihong; Tsao, Yu-Chia; Lee, Fu-Jung; Tsai, Woo-Hu; Wang, Ching-Ho; Chuang, Tsung-Liang; Wu, Mu-Shiang; Lin, Chii-Wann

2016-07-01

A side-polished fiber optic surface plasmon resonance (SPR) sensor was fabricated to expose the core surface and then deposited with a 40 nm thin gold film for the near surface sensing of effective refractive index changes with surface concentration or thickness of captured avian influenza virus subtype H6. The detection surface of the SPR optical fiber sensor was prepared through the plasma modification method for binding a self-assembled monolayer of isopropanol chemically on the gold surface of the optical fiber. Subsequently, N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide/N-hydroxysuccinimide was activated to enable EB2-B3 monoclonal antibodies to capture A/chicken/Taiwan/2838V/00 (H6N1) through a flow injection system. The detection limit of the fabricated optical fiber sensor for A/chicken/Taiwan/2838V/00 was 5.14 × 10(5) EID50/0.1 mL, and the response time was 10 min on average. Moreover, the fiber optic sensor has the advantages of a compact size and low cost, thus rendering it suitable for online and remote sensing. The results indicated that the optical fiber sensor can be used for epidemiological surveillance and diagnosing of avian influenza subtype H6 rapidly. Copyright © 2016 Elsevier B.V. All rights reserved.

Aqueous carrier waveguide in a flow cytometer

DOEpatents

Mariella, Jr., Raymond P.; van den Engh, Gerrit; Northrup, M. Allen

1995-01-01

The liquid of a flow cytometer itself acts as an optical waveguide, thus transmitting the light to an optical filter/detector combination. This alternative apparatus and method for detecting scattered light in a flow cytometer is provided by a device which views and detects the light trapped within the optical waveguide formed by the flow stream. A fiber optic or other light collecting device is positioned within the flow stream. This provides enormous advantages over the standard light collection technique which uses a microscope objective. The signal-to-noise ratio is greatly increased over that for right-angle-scattered light collected by a microscope objective, and the alignment requirements are simplified.

Fiber optic illumination of a poly(dimethylsiloxane) sheath flow cuvette for diode laser induced fluorescence detection in capillary electrophoresis.

PubMed

Skinner, Cameron D

2015-02-01

A Tee configuration sheath flow cuvette with square cross-section channels has been produced in PDMS for CE detection. The output of a 1.4 W laser diode operating at 450 nm was focused onto the 300 μm core of a 370 μm od fiber optic whose end was inserted into one arm of the Tee for LIF. The optimal configuration had the fiber optic positioned 500 μm downstream from the intersection and the end of the 35 cm 50 μm id 365 μm od capillary just outside the intersection and in the leg of the Tee, resulting in a 90° configuration. Detection limits of 50 and 3 pM and linear calibrations of at least three orders of magnitude were obtained for Lucifer Yellow and fluorescein, respectively. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Measuring electrically charged particle fluxes in space using a fiber optic loop sensor

NASA Technical Reports Server (NTRS)

1992-01-01

The purpose of this program was to demonstrate the potential of a fiber optic loop sensor for the measurement of electrically charged particle fluxes in space. The key elements of the sensor are a multiple turn loop of low birefringence, single mode fiber, with a laser diode light source, and a low noise optical receiver. The optical receiver is designed to be shot noise limited, with this being the limiting sensitivity factor for the sensor. The sensing element is the fiber optic loop. Under a magnetic field from an electric current flowing along the axis of the loop, there is a non-vanishing line integral along the fiber optic loop. This causes a net birefringence producing two states of polarization whose phase difference is correlated to magnetic field strength and thus, current in the optical receiver electronic processing. The objectives in this program were to develop a prototype laser diode powered fiber optic sensor. The performance specification of a minimum detectable current density of 1 (mu)amp/sq m-(radical)Hz, should be at the shot noise limit of the detection electronics. OPTRA has successfully built and tested a 3.2 m diameter loop with 137 turns of low birefringence optical fiber and achieved a minimum detectable current density of 5.4 x 10(exp-5) amps/(radical)Hz. If laboratory space considerations were not an issue, with the length of optical fiber available to us, we would have achieved a minimum detectable current density of 4 x 10(exp -7) amps/(radical)Hz.

Optical characteristics of modified fiber tips in single fiber, laser Doppler flowmetry

NASA Astrophysics Data System (ADS)

Oberg, P. Ake; Cai, Hongming; Rohman, Hakan; Larsson, Sven-Erik

1994-02-01

Percutaneous laser Doppler flowmetry (LDF) and bipolar surface electromyography (EMG) were used simultaneously for measurement of skeletal muscle (trapezius) perfusion in relation to static load and fatigue. On-line computer (386 SX) processing of the LDF- and EMG- signals made possible interpretation of the relationship between the perfusion and the activity of the muscle. The single fiber laser Doppler technique was used in order to minimize the trauma. A ray-tracing program was developed in the C language by which the optical properties of the fiber and fiber ends could be simulated. Isoirradiance graphs were calculated for three fiber end types and the radiance characteristics were measured for each fiber end. The three types of fiber-tips were evaluated and compared in flow model measurements.

Femtosecond laser fabrication of fiber based optofluidic platform for flow cytometry applications

NASA Astrophysics Data System (ADS)

Serhatlioglu, Murat; Elbuken, Caglar; Ortac, Bulend; Solmaz, Mehmet E.

2017-02-01

Miniaturized optofluidic platforms play an important role in bio-analysis, detection and diagnostic applications. The advantages of such miniaturized devices are extremely low sample requirement, low cost development and rapid analysis capabilities. Fused silica is advantageous for optofluidic systems due to properties such as being chemically inert, mechanically stable, and optically transparent to a wide spectrum of light. As a three dimensional manufacturing method, femtosecond laser scanning followed by chemical etching shows great potential to fabricate glass based optofluidic chips. In this study, we demonstrate fabrication of all-fiber based, optofluidic flow cytometer in fused silica glass by femtosecond laser machining. 3D particle focusing was achieved through a straightforward planar chip design with two separately fabricated fused silica glass slides thermally bonded together. Bioparticles in a fluid stream encounter with optical interrogation region specifically designed to allocate 405nm single mode fiber laser source and two multi-mode collection fibers for forward scattering (FSC) and side scattering (SSC) signals detection. Detected signal data collected with oscilloscope and post processed with MATLAB script file. We were able to count number of events over 4000events/sec, and achieve size distribution for 5.95μm monodisperse polystyrene beads using FSC and SSC signals. Our platform shows promise for optical and fluidic miniaturization of flow cytometry systems.

Processes for design, construction and utilisation of arrays of light-emitting diodes and light-emitting diode-coupled optical fibres for multi-site brain light delivery

PubMed Central

Bernstein, Jacob G.; Allen, Brian D.; Guerra, Alexander A.; Boyden, Edward S.

2016-01-01

Optogenetics enables light to be used to control the activity of genetically targeted cells in the living brain. Optical fibers can be used to deliver light to deep targets, and LEDs can be spatially arranged to enable patterned light delivery. In combination, arrays of LED-coupled optical fibers can enable patterned light delivery to deep targets in the brain. Here we describe the process flow for making LED arrays and LED-coupled optical fiber arrays, explaining key optical, electrical, thermal, and mechanical design principles to enable the manufacturing, assembly, and testing of such multi-site targetable optical devices. We also explore accessory strategies such as surgical automation approaches as well as innovations to enable low-noise concurrent electrophysiology. PMID:26798482

Fiber optic fluid detector

DOEpatents

Angel, S. Michael

1989-01-01

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.

A plasmonic optical fiber patterned by template transfer as a high-performance flexible nanoprobe for real-time biosensing

NASA Astrophysics Data System (ADS)

Jia, Peipei; Yang, Jun

2014-07-01

Surface plasmon resonance (SPR) on metal nanostructures offers a promising route for manipulation and interrogation of light in the subwavelength regime. However, the utility of SPR structures is largely limited by currently used complex nanofabrication methods and relatively sophisticated optical components. Here to relieve these restrictions, plasmonic optical fibers are constructed by transferring periodic metal nanostructures from patterned templates onto endfaces of optical fibers using an epoxy adhesive. Patterned metal structures are generally extended from two-dimensional (2D) nanohole arrays to one-dimensional (1D) nanoslit arrays. By controlling the viscosity of the adhesive layer, diverse surface topographies of metal structures are realized with the same template. We design a special plasmonic fiber that simultaneously implements multimode refractive index sensing (transmission and reflection) with remarkably narrow linewidth (6.6 nm) and high figure of merit (60.7), which are both among the best reported values for SPR sensors. We further demonstrate a real-time immunoassay relying on our plasmonic fiber integrated with a special flow cell. Plasmonic optical fibers also take advantages of excellent stability during fiber bending and capability of spectrum filtering. These features enable our plasmonic fibers to open up an alternative avenue for the general community in biosensing and nanoplasmonics.

A plasmonic optical fiber patterned by template transfer as a high-performance flexible nanoprobe for real-time biosensing.

PubMed

Jia, Peipei; Yang, Jun

2014-08-07

Surface plasmon resonance (SPR) on metal nanostructures offers a promising route for manipulation and interrogation of light in the subwavelength regime. However, the utility of SPR structures is largely limited by currently used complex nanofabrication methods and relatively sophisticated optical components. Here to relieve these restrictions, plasmonic optical fibers are constructed by transferring periodic metal nanostructures from patterned templates onto endfaces of optical fibers using an epoxy adhesive. Patterned metal structures are generally extended from two-dimensional (2D) nanohole arrays to one-dimensional (1D) nanoslit arrays. By controlling the viscosity of the adhesive layer, diverse surface topographies of metal structures are realized with the same template. We design a special plasmonic fiber that simultaneously implements multimode refractive index sensing (transmission and reflection) with remarkably narrow linewidth (6.6 nm) and high figure of merit (60.7), which are both among the best reported values for SPR sensors. We further demonstrate a real-time immunoassay relying on our plasmonic fiber integrated with a special flow cell. Plasmonic optical fibers also take advantages of excellent stability during fiber bending and capability of spectrum filtering. These features enable our plasmonic fibers to open up an alternative avenue for the general community in biosensing and nanoplasmonics.

Aqueous carrier waveguide in a flow cytometer

DOEpatents

Mariella, R.P. Jr.; Engh, G. van den; Northrup, M.A.

1995-12-12

The liquid of a flow cytometer itself acts as an optical waveguide, thus transmitting the light to an optical filter/detector combination. This alternative apparatus and method for detecting scattered light in a flow cytometer is provided by a device which views and detects the light trapped within the optical waveguide formed by the flow stream. A fiber optic or other light collecting device is positioned within the flow stream. This provides enormous advantages over the standard light collection technique which uses a microscope objective. The signal-to-noise ratio is greatly increased over that for right-angle-scattered light collected by a microscope objective, and the alignment requirements are simplified. 6 figs.

Optical Electronic Bragg Reflection Sensor System with Hydrodynamic Flow Applications

NASA Technical Reports Server (NTRS)

Lyons, D. R.

2003-01-01

This project, as described in the following report, involved design and fabrication of fiber optic sensors for the detection and measurement of dynamic fluid density variations. These devices are created using UV (ultraviolet) ablation and generally modified transverse holographic fiber grating techniques. The resulting phase gratings created on or immediately underneath the flat portion of D-shaped optical waveguides are characterized as evanescent field sensing devices. The primary applications include the sensor portion of a real-time localized or distributed measurement system for hydrodynamic flow, fluid density measurements, and phase change phenomena. Several design modifications were implemented in an attempt to accomplish the tasks specified in our original proposal. In addition, we have established key collaborative relationships with numerous people and institutions.

A commercialized, continuous flow fiber optic sensor for trichloroethylene and haloforms

NASA Technical Reports Server (NTRS)

Wells, James C.; Johnson, Mark D.

1994-01-01

Purus, Inc. has commercialized a fiber optic chemical sensor using technology developed by Lawrence Livermore National Laboratory and licensed from The University of California. The basis for the sensor is the development of color within a reagent when exposed to an analyte. The sensor consists of an optrode, reagent delivery and recover system, fiber optic transmitter-receiver, controller, and display. Reagent is pumped through the optrode. Analyte diffuses across a gas permeable membrane and reacts with the reagent to form a colored product. The colored product is detected by measuring the absorbance of light from a 568 nm diode. Reagents are currently available for TCE and trihalomethanes. Initial reagent chemistry is based on the Fujiwara alkaline pyridine reaction. The optrode contacts only gas streams, but the volatility of the current analytes also allows measurements of aqueous streams, without being affected by aqueous interferents that are non-volatile. Sensitivity of the sensor has been demonstrated to 5 ppb aqueous solutions and 0.1 ppmv in flowing gas streams.

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

PubMed

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

2015-02-18

Long-term monitoring with optical fibers has moved into the focus of attention due to the applicability for medical measurements. Within this Review, setups of flexible, unobtrusive body-monitoring systems based on optical fibers and the respective measured vital parameters are in focus. Optical principles are discussed as well as the interaction of light with tissue. Optical fiber-based sensors that are already used in first trials are primarily selected for the section on possible applications. These medical textiles include the supervision of respiration, cardiac output, blood pressure, blood flow and its saturation with hemoglobin as well as oxygen, pressure, shear stress, mobility, gait, temperature, and electrolyte balance. The implementation of these sensor concepts prompts the development of wearable smart textiles. Thus, current sensing techniques and possibilities within photonic textiles are reviewed leading to multiparameter designs. Evaluation of these designs should show the great potential of optical fibers for the introduction into textiles especially due to the benefit of immunity to electromagnetic radiation. Still, further improvement of the signal-to-noise ratio is often necessary to develop a commercial monitoring system. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

UV-transmitting step-index fluorophosphate glass fiber fabricated by the crucible technique

NASA Astrophysics Data System (ADS)

Galleani, Gustavo; Ledemi, Yannick; de Lima Filho, Elton Soares; Morency, Steeve; Delaizir, Gaëlle; Chenu, Sébastien; Duclere, Jean René; Messaddeq, Younes

2017-02-01

In this study, we report on the fabrication process of highly pure step-index fluorophosphate glass optical fibers by a modified crucible technique. High-purity fluorophosphate glasses based on 10 mol% of barium metaphosphate and 90 mol% of metal fluorides (AlF3sbnd CaF2sbnd MgF2sbnd SrF2) have been studied in order to produce step-index optical fibers transmitting in the deep-ultraviolet (DUV) region. The characteristic temperatures, viscosity around softening temperature and optical transmission in the UV-visible region of the prepared bulk glasses were characterized in a first step. The selected glass compositions were then used to prepare core-cladding optical preforms by using a modified built-in casting technique. While uncontrolled crystallization of the fiber was observed during the preform stretching by using the conventional method, we successfully obtained crystal-free fiber by using a modified crucible technique. In this alternative approach, the produced core-cladding preforms were inserted into a home-designed fused silica crucible assembly and heated at 643 °C to allow glass flowing throughout the crucible, preventing the formation of crystals. Single index fluorophosphate glass fibers were fabricated following the same process as well. The optical attenuation at 244 nm and in the interval 350-1750 nm was measured on both single index and step-index optical fibers. Their potential for using in DUV applications is discussed.

Fire Source Localization Based on Distributed Temperature Sensing by a Dual-Line Optical Fiber System.

PubMed

Sun, Miao; Tang, Yuquan; Yang, Shuang; Li, Jun; Sigrist, Markus W; Dong, Fengzhong

2016-06-06

We propose a method for localizing a fire source using an optical fiber distributed temperature sensor system. A section of two parallel optical fibers employed as the sensing element is installed near the ceiling of a closed room in which the fire source is located. By measuring the temperature of hot air flows, the problem of three-dimensional fire source localization is transformed to two dimensions. The method of the source location is verified with experiments using burning alcohol as fire source, and it is demonstrated that the method represents a robust and reliable technique for localizing a fire source also for long sensing ranges.

Integrated microfluidic flowmeter based on a micro-FBG inscribed in Co²⁺-doped optical fiber.

PubMed

Liu, Zhengyong; Tse, Ming-Leung Vincent; Zhang, A Ping; Tam, Hwa-Yaw

2014-10-15

A novel microfluidic flowmeter integrated with microfiber Bragg grating (µFBG) is presented. Two glass capillaries and a short length of high-light-absorption Co²⁺-doped optical fiber were stacked inside a larger outer capillary tube. The stack was then drawn into a tapered device. Two microchannels with the diameter of ~50  μm were formed inside the capillaries for flowing of microfluidics. An FBG was inscribed in the tapered Co²⁺-doped fiber with waist diameter of ~70  μm, and acts as a flow-rate sensor. A pump laser with wavelength of 1480 nm was utilized to locally heat the µFBG, rendering the µFBG as miniature "hot-wire" flowmeter. The flow rate of the liquid in the microchannels is determined by the induced wavelength shift of the µFBG. The experimental results achieve a minimum detectable change of ~16  nL/s in flow rate, which is very promising in the use as part of biochips.

Distributed Optical Fiber Sensors Based on Optical Frequency Domain Reflectometry: A review

PubMed Central

Wang, Chenhuan; Liu, Kun; Jiang, Junfeng; Yang, Di; Pan, Guanyi; Pu, Zelin; Liu, Tiegen

2018-01-01

Distributed optical fiber sensors (DOFS) offer unprecedented features, the most unique one of which is the ability of monitoring variations of the physical and chemical parameters with spatial continuity along the fiber. Among all these distributed sensing techniques, optical frequency domain reflectometry (OFDR) has been given tremendous attention because of its high spatial resolution and large dynamic range. In addition, DOFS based on OFDR have been used to sense many parameters. In this review, we will survey the key technologies for improving sensing range, spatial resolution and sensing performance in DOFS based on OFDR. We also introduce the sensing mechanisms and the applications of DOFS based on OFDR including strain, stress, vibration, temperature, 3D shape, flow, refractive index, magnetic field, radiation, gas and so on. PMID:29614024

Distributed Optical Fiber Sensors Based on Optical Frequency Domain Reflectometry: A review.

PubMed

Ding, Zhenyang; Wang, Chenhuan; Liu, Kun; Jiang, Junfeng; Yang, Di; Pan, Guanyi; Pu, Zelin; Liu, Tiegen

2018-04-03

Distributed optical fiber sensors (DOFS) offer unprecedented features, the most unique one of which is the ability of monitoring variations of the physical and chemical parameters with spatial continuity along the fiber. Among all these distributed sensing techniques, optical frequency domain reflectometry (OFDR) has been given tremendous attention because of its high spatial resolution and large dynamic range. In addition, DOFS based on OFDR have been used to sense many parameters. In this review, we will survey the key technologies for improving sensing range, spatial resolution and sensing performance in DOFS based on OFDR. We also introduce the sensing mechanisms and the applications of DOFS based on OFDR including strain, stress, vibration, temperature, 3D shape, flow, refractive index, magnetic field, radiation, gas and so on.

Laser beam joining of optical fibers in silicon V-grooves

NASA Astrophysics Data System (ADS)

Kaufmann, Stefan; Otto, Andreas; Luz, Gerhard

2000-06-01

The increasing use of optical data transmission systems and the development of new optical components require adjustment-insensitive and reliable joining and assembling techniques. The state of the art includes the utilization of silicon submounts with anisotropically etched V-grooves. Several glass fibers are fixed in these V-grooves with adhesive. Adhesive bonds tend towards degradation under the influence of temperature and moisture. For this reason, the alternative joining processes laser beam welding and laser beam soldering are relevant. The goal is a reliable joining of optical fibers in V-grooves without damage to the fibers or the silicon submount. Because of the anomaly of silicon during phase transformation, a positive joining can be realized by laser beam welding. A melt pool is created through the energy of a Nd:YAG-laser pulse. During solidification, the volume of silicon increases and a bump is formed in the center. Experiments have shown that this phenomenon can be used for joining optical fibers in silicon-V-grooves. With suitable parameters the silicon flows half around the fiber during solidification. For each fiber, several welding points are necessary. Another promising joining method is laser bema soldering. In this case, a second silicon sheet with a solder deposit is placed on the fibers which lie in the V-grooves of the metallized silicon submount. The laser heats the upper silicon until the solder metals by heat conduction.

Optical Measurement of Mass Flow of a Two-Phase Fluid

NASA Technical Reports Server (NTRS)

Wiley, John; Pedersen, Kevin; Koman, Valentin; Gregory, Don

2008-01-01

An optoelectronic system utilizes wavelength-dependent scattering of light for measuring the density and mass flow of a two-phase fluid in a pipe. The apparatus was invented for original use in measuring the mass flow of a two-phase cryogenic fluid (e.g., liquid hydrogen containing bubbles of hydrogen gas), but underlying principles of operation can readily be adapted to non-cryogenic two-phase fluids. The system (see figure) includes a laser module, which contains two or more laser diodes, each operating at a different wavelength. The laser module also contains beam splitters that combine the beams at the various wavelengths so as to produce two output beams, each containing all of the wavelengths. One of the multiwavelength output beams is sent, via a multimode fiberoptic cable, to a transmitting optical coupler. The other multiwavelength output beam is sent, via another multimode fiber-optic cable, to a reference detector module, wherein fiber-optic splitters split the light into several multiwavelength beams, each going to a photodiode having a spectral response that is known and that differs from the spectral responses of the other photodiodes. The outputs of these photodiodes are digitized and fed to a processor, which executes an algorithm that utilizes the known spectral responses to convert the photodiode outputs to obtain reference laser-power levels for the various wavelengths. The transmitting optical coupler is mounted in (and sealed to) a hole in the pipe and is oriented at a slant with respect to the axis of the pipe. The transmitting optical coupler contains a collimating lens and a cylindrical lens that form the light emerging from the end of the fiber-optic cable into a fan-shaped beam in a meridional plane of the pipe. Receiving optical couplers similar to the transmitting optical couplers are mounted in the same meridional plane at various longitudinal positions on the opposite side of the pipe, approximately facing the transmitting optical coupler along the same slant. Light collected by each receiving optical coupler is sent, via a multimode fiber-optic cable, to a detector module similar to the reference detector module. The outputs of the photodiodes in each detector module are digitized and processed, similarly to those of the reference detector module, to obtain indications of the amounts of light of each wavelength scattered to the corresponding receiving position. The value for each wavelength at each position is also normalized to the reference laser-power level for that wavelength. From these normalized values, the density and the mass flow rate of the fluid are estimated.

Hollow fiber optics with improved durability for high-peak-power pulses of Q-switched Nd:YAG lasers.

PubMed

Matsuura, Yuji; Tsuchiuchi, Akio; Noguchi, Hiroshi; Miyagi, Mitsunobu

2007-03-10

To improve the damage threshold of hollow optical waveguides for transmitting Q-switched Nd:YAG laser pulses, we optimize the metallization processes for the inner coating of fibers. For silver-coated hollow fiber as the base, second, and third Nd:YAG lasers, drying silver films at a moderate temperature and with inert gas flow is found to be effective. By using this drying process, the resistance to high-peak-power optical pulse radiation is drastically improved for fibers fabricated with and without the sensitizing process. The maximum peak power transmitted in the fiber is greater than 20 MW. To improve the energy threshold of aluminum-coated hollow fibers for the fourth and fifth harmonics of Nd:YAG lasers, a thin silver film is added between the aluminum film and the glass substrate to increase adhesion of the aluminum coating. By using this primer layer, the power threshold improves to 3 MW for the fourth harmonics of a Q-switched Nd:YAG laser light.

Research and investigation of a communication chain on optical fiber with a Fabry-Perot power diode for the automotive industry

NASA Astrophysics Data System (ADS)

Bacis, Irina Bristena; Vasile, Alexandru; Ionescu, Ciprian; Marghescu, Cristina

2016-12-01

The purpose of this paper is to analyze different power devices - emitters of optical flow, from the point of view of optical coupling, emitted optical powers, optical fiber losses and receiver. The research and characterization of the transmission through a power optical system is done using a computer system specialized for the automotive industry. This system/platform can deliver current pulses that are controlled by a computer through a software (it is possible to set different parameters such as pulse repetition frequency, duty cycle, and current intensity). For the experiments a power Fabry Perot 1035 laser diode operating in pulse with μφ 1055 nm, Ith = 40 mA, and Iop =750 mA was used with a single-mode SFM 128 optical fiber and an EM type optical coupler connected through alignment. Two types of measurements were conducted to demonstrate the usefulness of the experimental structure. In the first case the amplitude of the voltage pulses was measured at the output of an optical detector with receiving diode in a built-in amplifier with a 50 kΩ load resistance. In the second stage measurements were conducted to determine the optical power injected in the optical fiber and received at the reception cell of a power meter. Another parameter of optical coupling that can be measured using the experimental structure is irradiation. This parameter is very important to determine the optimum cutting angle of the fiber for continuity welding.

Multisensor Instrument for Real-Time Biological Monitoring

NASA Technical Reports Server (NTRS)

Zhang, Sean (Zhanxiang); Xu, Guoda; Qiu, Wei; Lin, Freddie

2004-01-01

The figure schematically depicts an instrumentation system, called a fiber optic-based integration system (FOBIS), that is undergoing development to enable real-time monitoring of fluid cell cultures, bioprocess flows, and the like. The FOBIS design combines a micro flow cytometer (MFC), a microphotometer (MP), and a fluorescence-spectrum- or binding-force-measuring micro-sensor (MS) in a single instrument that is capable of measuring multiple biological parameters simultaneously or sequentially. The fiber-optic-based integration system is so named because the MFC, the MP, and the MS are integrated into a single optical system that is coupled to light sources and photometric equipment via optical fibers. The optical coupling components also include a wavelength-division multiplexer and diffractive optical elements. The FOBIS includes a laserdiode- and fiber-optic-based optical trapping subsystem (optical tweezers ) with microphotometric and micro-sensing capabilities for noninvasive confinement and optical measurement of relevant parameters of a single cell or other particle. Some of the measurement techniques implemented together by the FOBIS have long been used separately to obtain basic understanding of the optical properties of individual cells and other organisms, the optical properties of populations of organisms, and the interrelationships among these properties, physiology of the organisms, and physical processes that govern the media that surround the organisms. For example, flow cytometry yields information on numerical concentrations, cross-sectional areas, and types of cells or other particles. Micro-sensing can be used to measure pH and concentrations of oxygen, carbon dioxide, glucose, metabolites, calcium, and antigens in a cell-culture fluid, thereby providing feedback that can be helpful in improving control over a bioprocess. Microphotometry (including measurements of scattering and fluorescence) can yield further information about optically trapped individual particles. In addition to the multifunctionality not previously available in a single biological monitoring system, the FOBIS offers advantages of low mass, sensitivity, accuracy, portability, low cost, compactness (the overall dimensions of the fully developed FOBIS sensor head are expected to be less than 1 by 1 by 2 cm), and immunity to electromagnetic interference at suboptical frequencies. FOBIS could be useful in a variety of laboratory and field settings in such diverse endeavors as medical, veterinary, and general biological research; medical and veterinary diagnosis monitoring of industrial bioprocesses; and analysis of biological contaminants in air, water, and food.

Performance and safety of holmium: YAG laser optical fibers.

PubMed

Knudsen, Bodo E; Glickman, Randolph D; Stallman, Kenneth J; Maswadi, Saher; Chew, Ben H; Beiko, Darren T; Denstedt, John D; Teichman, Joel M H

2005-11-01

Lower-pole ureteronephroscopy requires transmission of holmium:YAG energy along a deflected fiber. Current ureteroscopes are capable of high degrees of deflection, which may stress laser fibers beyond safe limits during lower-pole use. We hypothesized that optical fiber and safety measures differ among manufacturers. Small (200-273-microm) and medium-diameter (300-400-microm) Ho:YAG fibers were tested in a straight and 180 degrees bent configuration. Energy transmission was measured by an energy detector. Fiber durability was assessed by firing the laser in sequentially tighter bending diameters. The fibers were bent to 180 degrees with a diameter of 6 cm and run at 200- to 4000-mJ pulse energy to determine the minimum energy required to fracture the fiber. The bending diameter was decreased by 1-cm increments and testing repeated until a bending diameter of 1 cm was reached. The maximum deflection of the ACMI DUR-8E ureteroscope with each fiber in the working channel was recorded. The flow rate through the working channel of the DUR-8E was measured for each fiber. The mean energy transmission differed among fibers (P < 0.001). The Lumenis SL 200 and the InnovaQuartz 400 were the best small and medium-diameter fibers, respectively, in resisting thermal breakdown (P < 0.01). The Dornier Lightguide Super 200 fractured repeatedly at a bend diameter of 2 cm and with the lowest energy (200 mJ). The other small fibers fractured only at a bend diameter of 1 cm. The Sharplan 200 and InnovaQuartz Sureflex 273T were the most flexible fibers, the Lumenis SL 365 the least. The flow rate was inversely proportional to four times the power of the diameter of the fiber. Optical performance and safety differ among fibers. Fibers transmit various amounts of energy to their cladding when bent. During lower-pole nephroscopy with the fiber deflected, there is a risk of fiber fracture from thermal breakdown and laser-energy transmission to the endoscope. Some available laser fibers carry a risk of ureteroscope damage.

A packaged, low-cost, robust optical fiber strain sensor based on small cladding fiber sandwiched within periodic polymer grating.

PubMed

Chiang, Chia-Chin; Li, Chein-Hsing

2014-06-02

In the present study, a novel packaged long-period fiber grating (PLPFG) strain sensor is first presented. The MEMS process was utilized to fabricate the packaged optical fiber strain sensor. The sensor structure consisted of etched optical fiber sandwiched between two layers of thick photoresist SU-8 3050 and then packaged with poly (dimethylsiloxane) (PDMS) polymer material to construct the PLPFG strain sensor. The PDMS packaging material was used to prevent the glue effect, wherein glue flows into the LPFG structure and reduces coupling strength, in the surface bonding process. Because the fiber grating was packaged with PDMS material, it was effectively protected and made robust. The resonance attenuation dip of PLPFG grows when it is loading. This study explored the size effect of the grating period and fiber diameter of PLPFG via tensile testing. The experimental results found that the best strain sensitivity of the PLPFG strain sensor was -0.0342 dB/με, and that an R2 value of 0.963 was reached.

Towards Silk Fiber Optics: Refractive Index Characterization, Fiber Spinning, and Spinneret Analysis

NASA Astrophysics Data System (ADS)

Spitzberg, Joshua David

Of the many biologically derived materials, whose historical record of use by humans underscores an ex-vivo utility, silk is interesting for it's contemporary repurposing from textile to biocompatible substrate. And while even within this category silk is one of several materials studied for novel repurposing, it has the unique character of being evolutionarily developed specifically for fiber spinning in vivo. The work discussed here is inspired by taking what nature has given, to explore the in vitro spinning of silk towards biocompatible fiber optics applications. A common formulation of silk used in biomedical studies for re-forming it into the various structures begins with the silkworm cocoon, which is degummed and dissolved into an aqueous solution of its miscible protein, fibroin, and post-treated to fabricate solid structures. In the first aim, the optical refractive index (RI) of various post-treatment methods is discussed towards determining RI design techniques. The methods considered in this work for re-forming a solid fiber from the reconstituted silk fibroin (RSF) solution borrow from the industrial techniques of gel spinning, and dry-spinning. In the second aim, methods are applied to RSF and quality of the spun fibers discussed. A feature common to spinning techniques is passing the (silk) material through a spinneret of specific shape. In the third aim, fluid flow through a simplified native silkworm spinneret is modeled towards bio-inspired lessons in design. In chapter 1 the history, reconstitution, are discussed towards understanding the fabrication of several optical device examples. Chapter 2 then prefaces the experiments and measurements in fiber optics by reviewing electromagnetic theory of waveguide function, and loss factors, to be considered in actual device fabrication. Chapter 3 presents results and discussion for the first aim, understanding design principles for the refractive index of RSF. From this point, industrial fiber-spinning approaches are reviewed from a theoretical and methodological perspective in chapter 4. Thus, chapter 5 presents results for the second aim, efforts to apply these techniques using RSF. Chapter 6 discusses the third aim, understanding the design of the silkworm spinneret by an idealized model of natural and reconstituted silk fibroin flow. While the ultimate goal of a structurally and optically smooth and uniform fiber remains elusive, this work serves as a guide for future efforts.

Fiber-optic manipulation of urinary stone phantoms using holmium:YAG and thulium fiber lasers.

PubMed

Blackmon, Richard L; Case, Jason R; Trammell, Susan R; Irby, Pierce B; Fried, Nathaniel M

2013-02-01

Fiber-optic attraction of urinary stones during laser lithotripsy may be exploited to manipulate stone fragments inside the urinary tract without mechanical grasping tools, saving the urologist time and space in the ureteroscope working channel. We compare thulium fiber laser (TFL) high pulse rate/low pulse energy operation to conventional holmium:YAG low pulse rate/high pulse energy operation for fiber-optic suctioning of plaster-of-paris (PoP) stone phantoms. A TFL (wavelength of 1908 nm, pulse energy of 35 mJ, pulse duration of 500 μs, and pulse rate of 10 to 350 Hz) and a holmium laser (wavelength of 2120 nm, pulse energy of 35 to 360 mJ, pulse duration of 300 μs, and pulse rate of 20 Hz) were tested using 270-μm-core optical fibers. A peak drag speed of ~2.5 mm/s was measured for both TFL (35 mJ and 150 to 250 Hz) and holmium laser (210 mJ and 20 Hz). Particle image velocimetry and thermal imaging were used to track water flow for all parameters. Fiber-optic suctioning of urinary stone phantoms is feasible. TFL operation at high pulse rates/low pulse energies is preferable to holmium operation at low pulse rates/high pulse energies for rapid and smooth stone pulling. With further development, this novel technique may be useful for manipulating stone fragments in the urinary tract.

Laser Ignition Technology for Bi-Propellant Rocket Engine Applications

NASA Technical Reports Server (NTRS)

Thomas, Matt; Bossard, John; Early, Jim; Trinh, Huu; Dennis, Jay; Turner, James (Technical Monitor)

2001-01-01

This viewgraph presentation gives an overview of laser ignition technology for bipropellant rocket engines applications. The objectives of this project include: (1) the selection test chambers and flows; (2) definition of the laser ignition setup; (3) pulse format optimization; (4) fiber optic coupled laser ignition system analysis; and (5) chamber integration issues definition. The testing concludes that rocket combustion chamber laser ignition is imminent. Support technologies (multiplexing, window durability/cleaning, and fiber optic durability) are feasible.

Lag compensation of optical fibers or thermocouples to achieve waveform fidelity in dynamic gas pyrometry

NASA Technical Reports Server (NTRS)

Warshawsky, I.

1991-01-01

Fidelity of waveform reproduction requires constant amplitude ratio and constant time lag of a temperature sensor's indication, at all frequencies of interest. However, heat-transfer type sensors usually cannot satisfy these requirements. Equations for the actual indication of a thermocouple and an optical-fiber pyrometer are given explicitly, in terms of sensor and flowing-gas properties. A practical, realistic design of each type of sensor behaves like a first-order system with amplitude-ratio attenuation inversely proportional to frequency when the frequency exceeds the corner frequency. Only at much higher frequencies does the amplitude-ratio attenuation for the optical fiber sensor become inversely proportional to the square root of the frequency. Design options for improving the frequency response are discussed. On-line electrical lag compensation, using a linear amplifier and a passive compensation network, can extend the corner frequency of the thermocouple 100-fold or more; a similar passive network can be used for the optical-fiber sensor. Design details for these networks are presented.

Electro-optic architecture (EOA) for sensors and actuators in aircraft propulsion systems

NASA Technical Reports Server (NTRS)

Glomb, W. L., Jr.

1989-01-01

Results of a study to design an optimal architecture for electro-optical sensing and control in advanced aircraft and space systems are described. The propulsion full authority digital Electronic Engine Control (EEC) was the focus for the study. The recommended architecture is an on-engine EEC which contains electro-optic interface circuits for fiber-optic sensors on the engine. Size and weight are reduced by multiplexing arrays of functionally similar sensors on a pair of optical fibers to common electro-optical interfaces. The architecture contains common, multiplex interfaces to seven sensor groups: (1) self luminous sensors; (2) high temperatures; (3) low temperatures; (4) speeds and flows; (5) vibration; (6) pressures; and (7) mechanical positions. Nine distinct fiber-optic sensor types were found to provide these sensing functions: (1) continuous wave (CW) intensity modulators; (2) time division multiplexing (TDM) digital optic codeplates; (3) time division multiplexing (TDM) analog self-referenced sensors; (4) wavelength division multiplexing (WDM) digital optic code plates; (5) wavelength division multiplexing (WDM) analog self-referenced intensity modulators; (6) analog optical spectral shifters; (7) self-luminous bodies; (8) coherent optical interferometers; and (9) remote electrical sensors. The report includes the results of a trade study including engine sensor requirements, environment, the basic sensor types, and relevant evaluation criteria. These figures of merit for the candidate interface types were calculated from the data supplied by leading manufacturers of fiber-optic sensors.

Bubble velocity, diameter, and void fraction measurements in a multiphase flow using fiber optic reflectometer

NASA Astrophysics Data System (ADS)

Lim, Ho-Joon; Chang, Kuang-An; Su, Chin B.; Chen, Chi-Yueh

2008-12-01

A fiber optic reflectometer (FOR) technique featuring a single fiber probe is investigated for its feasibility of measuring the bubble velocity, diameter, and void fraction in a multiphase flow. The method is based on the interference of the scattered signal from the bubble surface with the Fresnel reflection signal from the tip of the optical fiber. Void fraction is obtained with a high accuracy if an appropriate correction is applied to compensate the underestimated measurement value. Velocity information is accurately obtained from the reflected signals before the fiber tip touches the bubble surface so that several factors affecting the traditional dual-tip probes such as blinding, crawling, and drifting effects due to the interaction between the probe and bubbles can be prevented. The coherent signals reflected from both the front and rear ends of a bubble can provide velocity information. Deceleration of rising bubbles and particles due to the presence of the fiber probe is observed when they are very close to the fiber tip. With the residence time obtained, the bubble chord length can be determined by analyzing the coherent signal for velocity determination before the deceleration starts. The bubble diameters are directly obtained from analyzing the signals of the bubbles that contain velocity information. The chord lengths of these bubbles measured by FOR represent the bubble diameters when the bubble shape is spherical or represent the minor axes when the bubble shape is ellipsoidal. The velocity and size of bubbles obtained from the FOR measurements are compared with those obtained simultaneously using a high speed camera.

Design and realization of temperature measurement system based on optical fiber temperature sensor for wireless power transfer

NASA Astrophysics Data System (ADS)

Chen, Xi; Zeng, Shuang; Liu, Xiulan; Jin, Yuan; Li, Xianglong; Wang, Xiaochen

2018-02-01

The electric vehicles (EV) have become accepted by increasing numbers of people for the environmental-friendly advantages. A novel way to charge the electric vehicles is through wireless power transfer (WPT). The wireless power transfer is a high power transfer system. The high currents flowing through the transmitter and receiver coils increasing temperature affects the safety of person and charging equipment. As a result, temperature measurement for wireless power transfer is needed. In this paper, a temperature measurement system based on optical fiber temperature sensors for electric vehicle wireless power transfer is proposed. Initially, the thermal characteristics of the wireless power transfer system are studied and the advantages of optical fiber sensors are analyzed. Then the temperature measurement system based on optical fiber temperature sensor is designed. The system consists of optical subsystem, data acquisition subsystem and data processing subsystem. Finally, the system is tested and the experiment result shows that the system can realize 1°C precision and can acquire real-time temperature distribution of the coils, which can meet the requirement of the temperature measuring for wireless power transfer.

A compact optical fiber positioner

NASA Astrophysics Data System (ADS)

Hu, Hongzhuan; Wang, Jianping; Liu, Zhigang; Zhou, Zengxiang; Zhai, Chao; Chu, Jiaru

2016-07-01

In this paper, a compact optical fiber positioner is proposed, which is especially suitable for small scale and high density optical fiber positioning. Based on the positioning principle of double rotation, positioner's center shaft depends on planetary gear drive principle, meshing with the fixed annular gear central motor gear driving device to rotate, and the eccentric shaft rotated driving by a coaxial eccentric motor, both center and the eccentric shaft are supported by a rolling bearings; center and eccentric shaft are both designed with electrical zero as a reference point, and both of them have position-limiting capability to ensure the safety of fiber positioning; both eccentric and center shaft are designed to eliminating clearance with spring structure, and can eliminate the influence of gear gap; both eccentric and center motor and their driving circuit can be installed in the positioner's body, and a favorable heat sink have designed, the heat bring by positioning operation can be effectively transmit to design a focal plane unit through the aluminum component, on sleeve cooling spiral airway have designed, when positioning, the cooling air flow is inlet into install hole on the focal plate, the cooling air flow can effectively take away the positioning's heat, to eliminate the impact of the focus seeing. By measuring position device's sample results show that: the unit accuracy reached 0.01mm, can meet the needs of fiber positioning.

An improved optical scheme for self-mixing low-coherence flowmeters

NASA Astrophysics Data System (ADS)

Di Cecilia, Luca; Rovati, Luigi; Cattini, Stefano

2017-02-01

In this paper we present a fiber-based low-coherence self-mixing interferometer exploiting a single-arm approach to measure the flow in a pipe. The main advantages of the proposed system are the flexibility offered by fiber-connected optical head, a greater ease of alignment, the rejection of "common-mode" vibrations, and greater stability. Thanks to the use of a low-coherence source, the proposed system investigates the velocity of the scattering particles owing only in a fixed and well defined region located close to the duct wall itself. The reported experimental results demonstrate that in laminar flow regime the developed system is able to determine the flow and it is quite robust to variation in the scatterers concentration. Increasing the scatterers concentration of about 24 times, the sensitivity S has reduced of less than 30%.

Recent progress on mid-IR sensing with optical fibers

NASA Astrophysics Data System (ADS)

Kellner, Robert A.; Gobel, R.; Goetz, R.; Lendl, B.; Edl-Mizaikoff, B.; Tacke, Maurus; Katzir, Abraham

1995-09-01

Chemical sensors are analytical systems for the evaluation of compound- or ion-specific or - selective signals produced by specific or selective chemical reactions taking place at the interface between the chemically modified sensor surface and the substrate. The well known electrochemical sensing schemes have greatly contributed that sensors are considered now as the 'third supporting pillar of analytical chemistry' besides chromatography and spectroscopy. The aim of this paper is to describe the novel capabilities of chemical modified IR-transparent fibers as chemical IR-sensors for the on-line analysis of chlorinated hydrocarbons and organic compounds in aqueous solutions and gaseous mixtures, glucose, and sucrose in aqueous solution as developed in our laboratory. Moreover, the relative merits of this new method wil be depicted in comparison to other sensing techniques. Optical fiber sensors are novel analysis systems, based on molecular spectroscopy in the UV/VIS/IR-range. They benefit from the tremendous development in the field of optical fibers, an offspring of the telecommunication industry and the electronic revolution during the last few years. With the development of new materials besides the well known quartz fibers for the UV/VIS/NIR-range the optical window for fiber optic sensors was enlarged from 0,2 to 20 micrometers recently. The fiber length was increased recently to up to 2 meters for silver halides and approximately 10 meters for chalcogenides. New applications for environmental, food, and clinical sensing as well as process analysis are the driving force for modern research in IR-optical fiber sensors using mainly sapphire (Al2O3), chalcogenide (As-Se-Te) and silver halide (AgBr/AgCl) fibers and flow injection analysis (FIA) systems. Few representative examples for each of the various optical sensor types will be presented. Particular attention will be given to the use of silver halide fibers for the simultaneous determination of traces of chlorinated hydrocarbons in water and to FIA-systems for the process analysis of beverages.

Multiple sclerosis and optic nerve: an analysis of retinal nerve fiber layer thickness and color Doppler imaging parameters

PubMed Central

Akçam, H T; Capraz, I Y; Aktas, Z; Batur Caglayan, H Z; Ozhan Oktar, S; Hasanreisoglu, M; Irkec, C

2014-01-01

Purpose To compare both retinal nerve fiber layer thickness and orbital color Doppler ultrasonography parameters in patients with multiple sclerosis (MS) versus healthy controls. Methods This is an observational case–control study. Forty eyes from MS patients and twenty eyes from healthy volunteers were examined. Eyes were classified into three groups as group 1, eyes from MS patients with previous optic neuritis (n=20); group 2, eyes from MS patients without previous optic neuritis (n=20); and group 3, eyes from healthy controls (n=20). Following complete ophthalmologic examination and retinal nerve fiber layer thickness measurement for each group, blood flow velocities of posterior ciliary arteries, central retinal artery, ophthalmic artery, and superior ophthalmic vein were measured. Pourcelot index (resistive index), an indicator of peripheral vascular resistance, was also calculated. The statistical assessment was performed with the assistance of Pearson's Chi-square test, Mann–Whitney U-test, Kruskal–Wallis test, and Spearman's correlation test. Results The studied eyes exposed similar values in terms of intraocular pressure and central corneal thickness, implying no evidence in favor of glaucoma. All nerve fiber layer thickness values, except superior nasal quadrants, in group 1 were found to be significantly thinner than groups 2 and 3. Blood flow velocity and mean resistivity index parameters were similar in all the groups. Conclusions In MS patients, especially with previous optic neuritis, diminished retinal nerve fiber layer thickness was observed. Contrary to several studies in the current literature, no evidence supporting potential vascular origin of ocular involvement in MS was found. PMID:25081285

PATHOGENESIS OF OPTIC DISC EDEMA IN RAISED INTRACRANIAL PRESSURE

PubMed Central

Hayreh, Sohan Singh

2015-01-01

Optic disc edema in raised intracranial pressure was first described in 1853. Ever since, there has been a plethora of controversial hypotheses to explain its pathogenesis. I have explored the subject comprehensively by doing basic, experimental and clinical studies. My objective was to investigate the fundamentals of the subject, to test the validity of the previous theories, and finally, based on all these studies, to find a logical explanation for the pathogenesis. My studies included the following issues pertinent to the pathogenesis of optic disc edema in raised intracranial pressure: the anatomy and blood supply of the optic nerve, the roles of the sheath of the optic nerve, of the centripetal flow of fluids along the optic nerve, of compression of the central retinal vein, and of acute intracranial hypertension and its associated effects. I found that, contrary to some previous claims, an acute rise of intracranial pressure was not quickly followed by production of optic disc edema. Then, in rhesus monkeys, I produced experimentally chronic intracranial hypertension by slowly increasing in size space-occupying lesions, in different parts of the brain. Those produced raised cerebrospinal fluid pressure (CSFP) and optic disc edema, identical to those seen in patients with elevated CSFP. Having achieved that, I investigated various aspects of optic disc edema by ophthalmoscopy, stereoscopic color fundus photography and fluorescein fundus angiography, and light microscopic, electron microscopic, horseradish peroxidase and axoplasmic transport studies, and evaluated the effect of opening the sheath of the optic nerve on the optic disc edema. This latter study showed that opening the sheath resulted in resolution of optic disc edema on the side of the sheath fenestration, in spite of high intracranial CSFP, proving that a rise of CSFP in the sheath was the essential pre-requisite for the development of optic disc edema. I also investigated optic disc edema with raised CSFP in patients, by evaluating optic disc and fundus changes by stereoscopic fundus photography and fluorescein fundus angiography. Based on the combined information from all the studies discussed above, it is clear that the pathogenesis of optic disc edema in raised intracranial pressure is a mechanical phenomenon. It is primarily due to a rise of CSFP in the optic nerve sheath, which produces axoplasmic flow stasis in the optic nerve fibers in the surface nerve fiber layer and prelaminar region of the optic nerve head. Axoplasmic flow stasis then results in swelling of the nerve fibers, and consequently of the optic disc. Swelling of the nerve fibers and of the optic disc secondarily compresses the fine, low-pressure venules in that region, resulting in venous stasis and fluid leakage; that leads to the accumulation of extracellular fluid. Contrary to the previous theories, the various vascular changes seen in optic disc edema are secondary and not primary. Thus, optic disc edema in raised CSFP is due to a combination of swollen nerve fibers and the accumulation of extracellular fluid. My studies also provided information about the pathogeneses of visual disturbances in raised intracranial pressure. PMID:26453995

Pathogenesis of optic disc edema in raised intracranial pressure.

PubMed

Hayreh, Sohan Singh

2016-01-01

Optic disc edema in raised intracranial pressure was first described in 1853. Ever since, there has been a plethora of controversial hypotheses to explain its pathogenesis. I have explored the subject comprehensively by doing basic, experimental and clinical studies. My objective was to investigate the fundamentals of the subject, to test the validity of the previous theories, and finally, based on all these studies, to find a logical explanation for the pathogenesis. My studies included the following issues pertinent to the pathogenesis of optic disc edema in raised intracranial pressure: the anatomy and blood supply of the optic nerve, the roles of the sheath of the optic nerve, of the centripetal flow of fluids along the optic nerve, of compression of the central retinal vein, and of acute intracranial hypertension and its associated effects. I found that, contrary to some previous claims, an acute rise of intracranial pressure was not quickly followed by production of optic disc edema. Then, in rhesus monkeys, I produced experimentally chronic intracranial hypertension by slowly increasing in size space-occupying lesions, in different parts of the brain. Those produced raised cerebrospinal fluid pressure (CSFP) and optic disc edema, identical to those seen in patients with elevated CSFP. Having achieved that, I investigated various aspects of optic disc edema by ophthalmoscopy, stereoscopic color fundus photography and fluorescein fundus angiography, and light microscopic, electron microscopic, horseradish peroxidase and axoplasmic transport studies, and evaluated the effect of opening the sheath of the optic nerve on the optic disc edema. This latter study showed that opening the sheath resulted in resolution of optic disc edema on the side of the sheath fenestration, in spite of high intracranial CSFP, proving that a rise of CSFP in the sheath was the essential pre-requisite for the development of optic disc edema. I also investigated optic disc edema with raised CSFP in patients, by evaluating optic disc and fundus changes by stereoscopic fundus photography and fluorescein fundus angiography. Based on the combined information from all the studies discussed above, it is clear that the pathogenesis of optic disc edema in raised intracranial pressure is a mechanical phenomenon. It is primarily due to a rise of CSFP in the optic nerve sheath, which produces axoplasmic flow stasis in the optic nerve fibers in the surface nerve fiber layer and prelaminar region of the optic nerve head. Axoplasmic flow stasis then results in swelling of the nerve fibers, and consequently of the optic disc. Swelling of the nerve fibers and of the optic disc secondarily compresses the fine, low-pressure venules in that region, resulting in venous stasis and fluid leakage; that leads to the accumulation of extracellular fluid. Contrary to the previous theories, the various vascular changes seen in optic disc edema are secondary and not primary. Thus, optic disc edema in raised CSFP is due to a combination of swollen nerve fibers and the accumulation of extracellular fluid. My studies also provided information about the pathogeneses of visual disturbances in raised intracranial pressure. Copyright © 2015 Elsevier Ltd. All rights reserved.

The PolyScope: a modular design, semidisposable flexible ureterorenoscope system.

PubMed

Bader, Markus Juergen; Gratzke, Christian; Walther, Sebastian; Schlenker, Boris; Tilki, Derya; Hocaoglu, Yasemin; Sroka, Ronald; Stief, Christian Georg; Reich, Oliver

2010-07-01

To characterize the mechanical and optical properties of the PolyScope endoscope system and to examine the clinical outcome in patients who were undergoing ureteronephroscopy. Mechanical assessment involved measurement of the deflection angle and irrigation flow rate. Optical resolution and distortion, field and angle of view, and light transmission and output formed the optical assessment. Clinical assessment was made in a series of consecutive ureteronephroscopy procedures. The optical cord was disconnected after each procedure, and the image fiber was assessed for damage. The mean value for the angle of maximum active tip deflection with an empty working channel was 265 degrees (261-275 degrees). Deflection was impaired most with insertion of the 3.0 F basket (10% decrease) and least with an indwelling 220 microm laser fiber (2% decrease). Irrigation flow rate was 57 mL/min with an empty working channel. Flow was reduced by 50% and 68%, with the insertion of a 200 microm or 365 microm laser probe, respectively, and by 92.5% with a 3.2F basket. No damage to the image fiber occurred. The PolyScope optics system could identify a target of about 0.125 mm at a distance of 2 to 4 mm, based on 3 line-pairs/mm needed for clear identification. Lithotripsy of renal calculi was performed for 40 stone burdens in 32 patients; the resulting stone-free rate was 87.5%. The novel semidisposable ureteroscope system PolyScope was simple to use, effective, and reliable in this preliminary clinical evaluation. It overcomes the inherent fragility of comparable devices, which renders the need for maintenance unnecessary.

Embedded fiber optic sensors for monitoring processing, quality and structural health of resin transfer molded components

NASA Astrophysics Data System (ADS)

Keulen, C.; Rocha, B.; Yildiz, M.; Suleman, A.

2011-07-01

Due to their small size and flexibility fiber optics can be embedded into composite materials with little negative effect on strength and reliability of the host material. Fiber optic sensors such as Fiber Bragg Gratings (FBG) or Etched Fiber Sensors (EFS) can be used to detect a number of relevant parameters such as flow, degree of cure, quality and structural health throughout the life of a composite component. With a detection algorithm these embedded sensors can be used to detect damage in real time while the component remains in service. This paper presents the research being conducted on the use of fiber optic sensors for process and Structural Health Monitoring (SHM) of Resin Transfer Molded (RTM) composite structures. Fiber optic sensors are used at all life stages of an RTM composite panel. A laboratory scale RTM apparatus was developed with the capability of visually monitoring the resin filling process. A technique for embedding fiber optic sensors with this apparatus has also been developed. Both FBGs and EFSs have been embedded in composite panels using the apparatus. EFSs to monitor the fabrication process, specifically resin flow have been embedded and shown to be capable of detecting the presence of resin at various locations as it is injected into the mold. Simultaneously these sensors were multiplexed on the same fiber with FBGs, which have the ability to measure strain. Since multiple sensors can be multiplexed on a single fiber the number of ingress/egress locations required per sensor can be significantly reduced. To characterize the FBGs for strain detection tensile test specimens with embedded FBG sensors have been produced. These specimens have been instrumented with a resistive strain gauge for benchmarking. Both specimens and embedded sensors were characterized through tensile testing. Furthermore FBGs have been embedded into composite panels in a manner that is conducive to detection of Lamb waves generated with a centrally located PZT. To sense Lamb waves a high speed, high precision sensing technique is required to acquire data from embedded FBGs due to the high velocities and small strain amplitudes of these guided waves. A technique based on a filter consisting of a tunable FBG was developed. Since this filter is not dependant on moving parts, tests executed with this filter concluded with the detection of Lamb waves, removing the influence of temperature and operational strains. A damage detection algorithm was developed to detect and localize cracks and delaminations.

Analysis of seawater flow through optical fiber

NASA Astrophysics Data System (ADS)

Fernández López, Sheila; Carrera Ramírez, Jesús; Rodriguez Sinobar, Leonor; Benitez, Javier; Rossi, Riccardo; Laresse de Tetto, Antonia

2015-04-01

The relation between sea and coastal aquifer is very important to the human populations living in coastal areas. The interrelation involves the submarine ground water discharge of relatively fresh water to the sea and the intrusion of sea water into the aquifer, which impairs the quality of ground water. The main process in seawater intrusion is managed by fluid-density effects which control the displacement of saline water. The underlain salinity acts as the restoring force, while hydrodynamic dispersion and convection lead to a mixing and vertical displacement of the brine. Because of this, a good definition of this saltwater-freshwater interface is needed what is intimately joined to the study of the movements (velocity fields) of fresh and salt water. As it is well known, the flow of salt water studied in seawater intrusion in stationary state, is nearly null or very low. However, in the rest of cases, this flux can be very important, so it is necessary its study to a better comprehension of this process. One possible manner of carry out this analysis is through the data from optical fiber. So, to research the distribution and velocity of the fresh and saltwater in the aquifer, a fiber optic system (OF) has been installed in Argentona (Baix Maresme, Catalonia). The main objective is to obtain the distributed temperature measurements (OF-DTS) and made progress in the interpretation of the dynamic processes of water. For some applications, the optical fiber acts as a passive temperature sensor but in our case, the technique Heated Active Fiber Optic will be used. This is based on the thermal response of the ground as a heat emission source is introduced. The thermal properties of the soil, dependent variables of soil water content, will make a specific temperature distribution around the cable. From the analyzed data we will deduce the velocity field, the real objective of our problem. To simulate this phenomenon and the coupled transport and flow problem, dominant in seawater intrusion, a finite element code in C ++ language will be developed. Finally, the information obtained numerically with our code will be checked with the field information.

Compact light-emitting diode optical fiber immobilized TiO2 reactor for photocatalytic water treatment.

PubMed

O'Neal Tugaoen, Heather; Garcia-Segura, Sergi; Hristovski, Kiril; Westerhoff, Paul

2018-02-01

A key barrier to implementing photocatalysis is delivering light to photocatalysts that are in contact with aqueous pollutants. Slurry photocatalyst systems suffer from poor light penetration and require post-treatment to separate the catalyst. The alternative is to deposit photocatalysts on fixed films and deliver light onto the surface or the backside of the attached catalysts. In this study, TiO 2 -coated quartz optical fibers were coupled to light emitting diodes (OF/LED) to improve in situ light delivery. Design factors and mechanisms studied for OF/LEDs in a flow-through reactor included: (i) the influence of number of LED sources coupled to fibers and (ii) the use of multiple optical fibers bundled to a single LED. The light delivery mechanism from the optical fibers into the TiO 2 coatings is thoroughly discussed. To demonstrate influence of design variables, experiments were conducted in the reactor using the chlorinated pollutant para-chlorobenzoic acid (pCBA). From the degradation kinetics of pCBA, the quantum efficiencies (Φ) of oxidation and electrical energies per order (E EO ) were determined. The use of TiO 2 coated optical fiber bundles reduced the energy requirements to deliver photons and increased available surface area, which improved Φ and enhanced oxidative pollutant removal performance (E EO ). Copyright © 2017 Elsevier B.V. All rights reserved.

A fiber-optic water flow sensor based on laser-heated silicon Fabry-Pérot cavity

NASA Astrophysics Data System (ADS)

Liu, Guigen; Sheng, Qiwen; Resende Lisboa Piassetta, Geraldo; Hou, Weilin; Han, Ming

2016-05-01

A hot-wire fiber-optic water flow sensor based on laser-heated silicon Fabry-Pérot interferometer (FPI) has been proposed and demonstrated in this paper. The operation of the sensor is based on the convective heat loss to water from a heated silicon FPI attached to the cleaved enface of a piece of single-mode fiber. The flow-induced change in the temperature is demodulated by the spectral shifts of the reflection fringes. An analytical model based on the FPI theory and heat transfer analysis has been developed for performance analysis. Numerical simulations based on finite element analysis have been conducted. The analytical and numerical results agree with each other in predicting the behavior of the sensor. Experiments have also been carried to demonstrate the sensing principle and verify the theoretical analysis. Investigations suggest that the sensitivity at low flow rates are much larger than that at high flow rates and the sensitivity can be easily improved by increasing the heating laser power. Experimental results show that an average sensitivity of 52.4 nm/(m/s) for the flow speed range of 1.5 mm/s to 12 mm/s was obtained with a heating power of ~12 mW, suggesting a resolution of ~1 μm/s assuming a wavelength resolution of 0.05 pm.

Fiber-optic manipulation of urinary stone phantoms using holmium:YAG and thulium fiber lasers

NASA Astrophysics Data System (ADS)

Blackmon, Richard L.; Case, Jason R.; Trammell, Susan R.; Irby, Pierce B.; Fried, Nathaniel M.

2013-02-01

Fiber-optic attraction of urinary stones during laser lithotripsy may be exploited to manipulate stone fragments inside the urinary tract without mechanical grasping tools, saving the urologist time and space in the ureteroscope working channel. We compare thulium fiber laser (TFL) high pulse rate/low pulse energy operation to conventional holmium:YAG low pulse rate/high pulse energy operation for fiber-optic suctioning of plaster-of-paris (PoP) stone phantoms. A TFL (wavelength of 1908 nm, pulse energy of 35 mJ, pulse duration of 500 μs, and pulse rate of 10 to 350 Hz) and a holmium laser (wavelength of 2120 nm, pulse energy of 35 to 360 mJ, pulse duration of 300 μs, and pulse rate of 20 Hz) were tested using 270-μm-core optical fibers. A peak drag speed of ˜2.5 mm/s was measured for both TFL (35 mJ and 150 to 250 Hz) and holmium laser (210 mJ and 20 Hz). Particle image velocimetry and thermal imaging were used to track water flow for all parameters. Fiber-optic suctioning of urinary stone phantoms is feasible. TFL operation at high pulse rates/low pulse energies is preferable to holmium operation at low pulse rates/high pulse energies for rapid and smooth stone pulling. With further development, this novel technique may be useful for manipulating stone fragments in the urinary tract.

Plasma surface reflectance spectroscopy for non-invasive and continuous monitoring of extracellular component of blood

NASA Astrophysics Data System (ADS)

Sakota, Daisuke; Takatani, Setsuo

2012-04-01

To achieve the quantitative optical non-invasive diagnosis of blood during extracorporeal circulation therapies, the instrumental technique to extract extracellular spectra from whole blood was developed. In the circuit, the continuous blood flow was generated by a centrifugal blood pump. The oxygen saturation was maintained 100% by an oxygenator. The developed glass optical flow cell was attached to the outlet tubing of the oxygenator. The halogen lamp including the light from 400 to 900 nm wavelength was used for the light source. The light was guided into an optical fiber. The light emitted by the fiber was collimated and emitted to the flow cell flat surface at the incident angle of 45 degrees. The light just reflected on the boundary between inner surface of the flow cell and plasma at 45 degrees was detected by the detection fiber. The detected light was analyzed by a spectral photometer. The obtained spectrum from 400 to 600nm wavelength was not changed with respect to the hematocrit. In contrast, the signal in the spectral range was changed when the plasma free hemoglobin increased. By using two spectral range, 505+/-5 nm and 542.5+/-2.5 nm, the differential spectrum was correlated with the free hemoglobin at R2=0.99. On the other hand, as for the hematocrit, the differential spectrum was not correlated at R2=0.01. Finally, the plasma free hemoglobin was quantified with the accuracy of 22+/-19mg/dL. The result shows that the developed plasma surface reflectance spectroscopy (PSRS) can extract the plasma spectrum from flowing whole blood.

Microparticles controllable accumulation, arrangement, and spatial shaping performed by tapered-fiber-based laser-induced convection flow.

PubMed

Zhang, Yu; Lei, Jiaojie; Zhang, Yaxun; Liu, Zhihai; Zhang, Jianzhong; Yang, Xinghua; Yang, Jun; Yuan, Libo

2017-10-30

The ability to arrange cells and/or microparticles into the desired pattern is critical in biological, chemical, and metamaterial studies and other applications. Researchers have developed a variety of patterning techniques, which either have a limited capacity to simultaneously trap massive particles or lack the spatial resolution necessary to manipulate individual particle. Several approaches have been proposed that combine both high spatial selectivity and high throughput simultaneously. However, those methods are complex and difficult to fabricate. In this article, we propose and demonstrate a simple method that combines the laser-induced convection flow and fiber-based optical trapping methods to perform both regular and special spatial shaping arrangement. Essentially, we combine a light field with a large optical intensity gradient distribution and a thermal field with a large temperature gradient distribution to perform the microparticles shaping arrangement. The tapered-fiber-based laser-induced convection flow provides not only the batch manipulation of massive particles, but also the finer manipulation of special one or several particles, which break out the limit of single-fiber-based massive/individual particles photothermal manipulation. The combination technique allows for microparticles quick accumulation, single-layer and multilayer arrangement; special spatial shaping arrangement/adjustment, and microparticles sorting.

Fiber-optic control and thermometry of single-cell thermosensation logic.

PubMed

Fedotov, I V; Safronov, N A; Ermakova, Yu G; Matlashov, M E; Sidorov-Biryukov, D A; Fedotov, A B; Belousov, V V; Zheltikov, A M

2015-11-13

Thermal activation of transient receptor potential (TRP) cation channels is one of the most striking examples of temperature-controlled processes in cell biology. As the evidence indicating the fundamental role of such processes in thermosensation builds at a fast pace, adequately accurate tools that would allow heat receptor logic behind thermosensation to be examined on a single-cell level are in great demand. Here, we demonstrate a specifically designed fiber-optic probe that enables thermal activation with simultaneous online thermometry of individual cells expressing genetically encoded TRP channels. This probe integrates a fiber-optic tract for the delivery of laser light with a two-wire microwave transmission line. A diamond microcrystal fixed on the fiber tip is heated by laser radiation transmitted through the fiber, providing a local heating of a cell culture, enabling a well-controlled TRP-assisted thermal activation of cells. Online local temperature measurements are performed by using the temperature-dependent frequency shift of optically detected magnetic resonance, induced by coupling the microwave field, delivered by the microwave transmission line, to nitrogen--vacancy centers in the diamond microcrystal. Activation of TRP channels is verified by using genetically encoded fluorescence indicators, visualizing an increase in the calcium flow through activated TRP channels.

Reagentless chemiluminescence-based fiber optic sensors for regenerative life support in space

NASA Astrophysics Data System (ADS)

Atwater, James E.; Akse, James R.; DeHart, Jeffrey; Wheeler, Richard R., Jr.

1995-04-01

The initial feasibility demonstration of a reagentless chemiluminescence based fiber optic sensor technology for use in advanced regenerative life support applications in space and planetary outposts is described. The primary constraints for extraterrestrial deployment of any technology are compatibility with microgravity and hypogravity environments; minimal size, weight, and power consumption; and minimal use of expendables due to the great expense and difficulty inherent to resupply logistics. In the current research, we report the integration of solid state flow through modules for the production of aqueous phase reagents into an integrated system for the detection of important analytes by chemiluminescence, with fiber optic light transmission. By minimizing the need for resupply expendables, the use of solid phase modules makes complex chemical detection schemes practical. For the proof of concept, hydrogen peroxide and glucose were chosen as analytes. The reaction is catalyzed by glucose oxidase, an immobilized enzyme. The aqueous phase chemistry required for sensor operation is implemented using solid phase modules which adjust the pH of the influent stream, catalyze the oxidation of analyte, and provide the controlled addition of the luminophore to the flowing aqueous stream. Precise control of the pH has proven essential for the long-term sustained release of the luminophore. Electrocatalysis is achieved using a controlled potential across gold mesh and gold foil electrodes which undergo periodic polarity reversals. The development and initial characterization of performance of the reagentless fiber optic chemiluminescence sensors are presented in this paper.

High-resolution flying-PIV with optical fiber laser delivery

NASA Astrophysics Data System (ADS)

Weichselbaum, Noah A.; André, Matthieu A.; Rahimi-Abkenar, Morteza; Manzari, Majid T.; Bardet, Philippe M.

2016-05-01

Implementation of non-intrusive optical measurement techniques, such as particle image velocimetry (PIV), in harsh environments requires specialized techniques for introducing controlled laser sheets to the region of interest. Large earthquake shake tables are a particularly challenging environment. Lasers must be mounted away from the table, and the laser sheet has to be delivered precisely and stably to the measurement station. Here, high-power multi-mode step-index fiber optics enable introduction of light from an Nd:YLF pulsed laser to a remote test section. Such lasers are suitable for coupling to optical fibers, which presents a portable, flexible, and safe manner to deliver a PIV light sheet. Best practices for their implementation are reviewed. Particular attention is focused on obtaining a collimated beam of acceptable quality at the output of the fiber. To achieve high spatial resolution, the PIV camera is directly mounted on the moving shake table with care to minimize its vibrations. A special arrangement of PIV planes is deployed for precise in-situ PIV alignment and to monitor and account for residual structure vibrations and beam wandering. The design of the instruments is detailed. Here, an experimental facility for the study of nuclear fuel bundle response to seismic forcing near prototypical conditions is instrumented. Only through integration of a high-resolution flying-PIV system can velocity fields be acquired. Data indicate that in the presence of a mean axial flow, a secondary oscillatory flow develops as the bundle oscillates. Instantaneous, phase-averaged, and fluctuating velocity fields illustrate this phenomenon.

Rayleigh Scattering Diagnostic for Measurement of Temperature and Velocity in Harsh Environments

NASA Technical Reports Server (NTRS)

Seasholtz, Richard G.; Greer, Lawrence C., III

1998-01-01

A molecular Rayleigh scattering system for temperature and velocity measurements in unseeded flows is described. The system is capable of making measurements in the harsh environments commonly found in aerospace test facilities, which may have high acoustic sound levels, varying temperatures, and high vibration levels. Light from an argon-ion laser is transmitted via an optical fiber to a remote location where two flow experiments were located. One was a subsonic free air jet; the second was a low-speed heated airjet. Rayleigh scattered light from the probe volume was transmitted through another optical fiber from the remote location to a controlled environment where a Fabry-Perot interferometer and cooled CCD camera were used to analyze the Rayleigh scattered light. Good agreement between the measured velocity and the velocity calculated from isentropic flow relations was demonstrated (less than 5 m/sec). The temperature measurements, however, exhibited systematic errors on the order of 10-15%.

Optical aggregometry of red blood cells associated with the blood-clotting reaction in extracorporeal circulation support.

PubMed

Sakota, Daisuke; Kosaka, Ryo; Nishida, Masahiro; Maruyama, Osamu

2016-09-01

The aggregability of red blood cell (RBCs) is associated with the contribution of plasma proteins, such as fibrinogen and lipoproteids, to blood-clotting. Hence, we hypothesized that RBC aggregability reflects the blood-clotting reaction. A noninvasive optical monitoring method to measure RBC aggregability for the assessment of blood-clotting stage during mechanical circulatory support was developed. An in vitro thrombogenic test was conducted with a rotary blood pump using heparinized fresh porcine blood. Near-infrared laser light at a wavelength of 785 nm was guided by an optical fiber. The fibers for detecting incident, forward-, and backward-scattered light were fixed on the circuit tubing with an inner diameter of 1/4 inch. Because there is substantial RBC aggregation at low shear flow rates, a pulsatile flow was generated by controlling the pump rotational speed. The flow rate was changed from 0 to 8.5 L/min at a period of 40 s. The intensities of forward- and backward-scattered light changed dramatically when the flow stopped. The aggregability was evaluated by the increase ratio of the transmitted light intensity from the flow stopping in the low-flow condition. The experiment started when the anticoagulation was stopped by the addition of protamine into the circulating blood. Reduction in RBC aggregability was associated with a decrease in the amount of fibrinogen and the number of platelets. Continuous, noninvasive monitoring of thrombosis risk is possible using optical measurements combining pulsatile flow control of a rotary blood pump. RBC aggregometry is a potential label-free method for evaluating blood-clotting risk.

A microvolume molecularly imprinted polymer modified fiber-optic evanescent wave sensor for bisphenol A determination.

PubMed

Xiong, Yan; Ye, Zhongbin; Xu, Jing; Liu, Yucheng; Zhang, Hanyin

2014-04-01

A fiber-optic evanescent wave sensor for bisphenol A (BPA) determination based on a molecularly imprinted polymer (MIP)-modified fiber column was developed. MIP film immobilized with BPA was synthesized on the fiber column, and the sensor was then constructed by inserting the optical fiber prepared into a transparent capillary. A microchannel (about 2.0 μL) formed between the fiber and the capillary acted as a flow cell. BPA can be selectively adsorbed online by the MIP film and excited to produce fluorescence by the evanescent wave produced on the fiber core surface. The conditions for BPA enrichment, elution, and fluorescence detection are discussed in detail. The analytical measurements were made at 276 nm/306 nm (λ(ex)/λ(em)), and linearity of 3 × 10(-9)-5 × 10(-6) g mL(-1) BPA, a limit of detection of 1.7 × 10(-9) g mL(-1) BPA (3σ), and a relative standard deviation of 2.4% (n = 5) were obtained. The sensor selectivity and MIP binding measurement were also evaluated. The results indicated that the selectivity and sensitivity of the proposed fiber-optic sensor could be greatly improved by using MIP as a recognition and enrichment element. Further, by modification of the sensing and detection elements on the optical fiber, the proposed sensor showed the advantages of easy fabrication and low cost. The novel sensor configuration provided a platform for monitoring other species by simply changing the light source and sensing elements. The sensor presented has been successfully applied to determine BPA released from plastic products treated at different temperatures.

Development and utilization of new diagnostics for dense-phase pneumatic transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Louge, M.Y.; Jenkins, J.T.

Dense-phase pneumatic transport is an attractive means of conveying solids. Unfortunately, because of the high solid concentrations, this transport method is a difficult regime in which to carry out detailed measurements. Hence most details of the flow are unknown. In this context, the main objective of this work is to develop probes for local measurements of solid velocity and holdup in dense gas-solid flows. In particular, the authors have designed capacitance probes to measure local, time-dependent particle concentrations, and a new optical fiber probe based on laser-induced-phosphorescence to measure particle velocities. The principles for the capacitance and optical diagnostics weremore » given in the first and second quarterly reports. A final version of the optical fiber probe was designed in the previous reporting period. Because granular flows depends strongly on the nature of their interaction with a boundary, the authors have sought in the present reporting period to verify the boundary conditions recently calculated by Jenkins (J. Appl. Mech., in press (1991)) using computer simulations. 2 refs., 2 figs.« less

Component and Technology Development for Advanced Liquid Metal Reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, Mark

2017-01-30

The following report details the significant developments to Sodium Fast Reactor (SFR) technologies made throughout the course of this funding. This report will begin with an overview of the sodium loop and the improvements made over the course of this research to make it a more advanced and capable facility. These improvements have much to do with oxygen control and diagnostics. Thus a detailed report of advancements with respect to the cold trap, plugging meter, vanadium equilibration loop, and electrochemical oxygen sensor is included. Further analysis of the university’s moving magnet pump was performed and included in a section ofmore » this report. A continuous electrical resistance based level sensor was built and tested in the sodium with favorable results. Materials testing was done on diffusion bonded samples of metal and the results are presented here as well. A significant portion of this work went into the development of optical fiber temperature sensors which could be deployed in an SFR environment. Thus, a section of this report presents the work done to develop an encapsulation method for these fibers inside of a stainless steel capillary tube. High temperature testing was then done on the optical fiber ex situ in a furnace. Thermal response time was also explored with the optical fiber temperature sensors. Finally these optical fibers were deployed successfully in a sodium environment for data acquisition. As a test of the sodium deployable optical fiber temperature sensors they were installed in a sub-loop of the sodium facility which was constructed to promote the thermal striping effect in sodium. The optical fibers performed exceptionally well, yielding unprecedented 2 dimensional temperature profiles with good temporal resolution. Finally, this thermal striping loop was used to perform cross correlation velocimetry successfully over a wide range of flow rates.« less

Optical measurement of blood flow in exercising skeletal muscle: a pilot study

NASA Astrophysics Data System (ADS)

Wang, Detian; Baker, Wesley B.; Parthasarathy, Ashwin B.; Zhu, Liguo; Li, Zeren; Yodh, Arjun G.

2017-07-01

Blood flow monitoring during rhythm exercising is very important for sports medicine and muscle dieases. Diffuse correlation spectroscopy(DCS) is a relative new invasive way to monitor blood flow but suffering from muscle fiber motion. In this study we focus on how to remove exercise driven artifacts and obtain accurate estimates of the increase in blood flow from exercise. Using a novel fast software correlator, we measured blood flow in forearm flexor muscles of N=2 healthy adults during handgrip exercise, at a sampling rate of 20 Hz. Combining the blood flow and acceleration data, we resolved the motion artifact in the DCS signal induced by muscle fiber motion, and isolated the blood flow component of the signal from the motion artifact. The results show that muscle fiber motion strongly affects the DCS signal, and if not accounted for, will result in an overestimate of blood flow more than 1000%. Our measurements indicate rapid dilation of arterioles following exercise onset, which enabled blood flow to increase to a plateau of 200% in 10s. The blood flow also rapidly recovered to baseline following exercise in 10s. Finally, preliminary results on the dependence of blood flow from exercise intensity changes will be discussed.

Application of active distribute temperature sensing and fiber optic as sensors to determinate the unsaturated hydraulic conductivity curve

NASA Astrophysics Data System (ADS)

Zubelzu, Sergio; Rodriguez-Sinobas, Leonor; Sobrino, Fernando

2017-04-01

The development of methodologies for the characterization of soil water content through the use of distribute temperature sensing and fiber optic cable has allowed for modelling with high temporal and spatial accuracy water movement in soils. One of the advantage of using fiber optic as a sensor, compared with the traditional point water probes, is the possibility to measure the variable continuously along the cable every 0.125 m (up to a cable length of 1500) and every second. Traditionally, applications based on fiber optic as a soil water sensor apply the active heated fiber optic technique AHFO to follow the evolution soil water content during and after irrigation events or for hydrologic characterization. However, this paper accomplishes an original experience by using AHFO as a sensor to characterize the soil hydraulic conductivity curve in subsaturated conditions. The non lineal nature between the hidraulic conductivity curve and soil water, showing high slope in the range close to saturation ) favors the AHFO a most suitable sensor due to its ability to measure the variable at small time and length intervals. Thus, it is possible to obtain accurate and a large number of data to be used to estimate the hydraulic conductivity curve from de water flow general equation by numerical methods. Results are promising and showed the feasibility of this technique to estimate the hydraulic conductivity curve for subsaturated soils .

Effect of Solar Radiation on Fiber Optic Cables Used in Distributed Temperature Sensing (DTS) Applications

NASA Astrophysics Data System (ADS)

Neilson, B. T.; Hatch, C. E.; Bingham, Q. G.; Tyler, S. W.

2008-12-01

In recent years, distributed temperature sensing (DTS) has enjoyed steady increases in the number and diversity of applications. Because fiber optic cables used for DTS are typically sheathed in dark materials resistant to UV deterioration, the question arises of how shortwave solar radiation penetrating a water column influences the accuracy of absolute DTS-derived temperatures. Initial calculations of these affects considered: shortwave radiation as a function of time of day, water depth, and water clarity; fiber optic cable dimensions; and fluid velocity. These indicate that for clear waterbodies with low velocities and shallow depths, some heating on the cable is likely during peak daily solar radiation. Given higher water velocities, substantial increases in turbidity, and/or deeper water, there should be negligible solar heating on the cable. To confirm these calculations, a field study was conducted to test the effects of solar radiation by installing two types of fiber optic cable at multiple, uniform depths in a trapezoidal canal with constant flow determined by a controlled release from Porcupine Dam near Paradise, Utah. Cables were installed in water depths from 0.05 to 0.79 m in locations of faster (center of canal) and slower (sidewall) water velocities. Thermister strings were installed at the same depths, but shielded from solar radiation and designed to record absolute water temperatures. Calculations predict that at peak solar radiation, in combination with shallow depths and slow velocities, typical fiber-optic cable is likely to experience heating greater than the ambient water column. In this study, DTS data show differences of 0.1-0.2°C in temperatures as seen by cables separated vertically by 0.31 m on the sidewall and center of the channel. Corresponding thermister data showed smaller vertical differences (~0.03-0.1°C) suggesting thermal stratification was also present in the canal. However, the magnitude of the DTS differences could not be fully explained by stratification alone. Additional information from cables installed in a shallow, near-zero velocity pool showed significantly higher temperature differences with cable depth when compared to the cable in the higher-velocity canal flows. This indicates a higher potential for heating of fiber-optic cable in stagnant, shallow waters. With sufficient water velocities and depths, the effect of shortwave solar radiation on DTS measurement accuracy via heating of the fiber- optic cable is negligible. Particular care in experimental design is recommended in shallow or low-velocity systems, including consideration of solar radiation, and independent quantification of (or calibration for) absolute temperatures.

Miniaturized flow injection analysis system

DOEpatents

Folta, James A.

1997-01-01

A chemical analysis technique known as flow injection analysis, wherein small quantities of chemical reagents and sample are intermixed and reacted within a capillary flow system and the reaction products are detected optically, electrochemically, or by other means. A highly miniaturized version of a flow injection analysis system has been fabricated utilizing microfabrication techniques common to the microelectronics industry. The microflow system uses flow capillaries formed by etching microchannels in a silicon or glass wafer followed by bonding to another wafer, commercially available microvalves bonded directly to the microflow channels, and an optical absorption detector cell formed near the capillary outlet, with light being both delivered and collected with fiber optics. The microflow system is designed mainly for analysis of liquids and currently measures 38.times.25.times.3 mm, but can be designed for gas analysis and be substantially smaller in construction.

High-Speed Optical Wide-Area Data-Communication Network

NASA Technical Reports Server (NTRS)

Monacos, Steve P.

1994-01-01

Proposed fiber-optic wide-area network (WAN) for digital communication balances input and output flows of data with its internal capacity by routing traffic via dynamically interconnected routing planes. Data transmitted optically through network by wavelength-division multiplexing in synchronous or asynchronous packets. WAN implemented with currently available technology. Network is multiple-ring cyclic shuffle exchange network ensuring traffic reaches its destination with minimum number of hops.

Characterization of Sodium Thermal Hydraulics with Optical Fiber Temperature Sensors

NASA Astrophysics Data System (ADS)

Weathered, Matthew Thomas

The thermal hydraulic properties of liquid sodium make it an attractive coolant for use in Generation IV reactors. The liquid metal's high thermal conductivity and low Prandtl number increases efficiency in heat transfer at fuel rods and heat exchangers, but can also cause features such as high magnitude temperature oscillations and gradients in the coolant. Currently, there exists a knowledge gap in the mechanisms which may create these features and their effect on mechanical structures in a sodium fast reactor. Two of these mechanisms include thermal striping and thermal stratification. Thermal striping is the oscillating temperature field created by the turbulent mixing of non-isothermal flows. Usually this occurs at the reactor core outlet or in piping junctions and can cause thermal fatigue in mechanical structures. Meanwhile, thermal stratification results from large volumes of non-isothermal sodium in a pool type reactor, usually caused by a loss of coolant flow accident. This stratification creates buoyancy driven flow transients and high temperature gradients which can also lead to thermal fatigue in reactor structures. In order to study these phenomena in sodium, a novel method for the deployment of optical fiber temperature sensors was developed. This method promotes rapid thermal response time and high spatial temperature resolution in the fluid. The thermal striping and stratification behavior in sodium may be experimentally analyzed with these sensors with greater fidelity than ever before. Thermal striping behavior at a junction of non-isothermal sodium was fully characterized with optical fibers. An experimental vessel was hydrodynamically scaled to model thermal stratification in a prototypical sodium reactor pool. Novel auxiliary applications of the optical fiber temperature sensors were developed throughout the course of this work. One such application includes local convection coefficient determination in a vessel with the corollary application of level sensing. Other applications were cross correlation velocimetry to determine bulk sodium flow rate and the characterization of coherent vortical structures in sodium with temperature frequency data. The data harvested, instrumentation developed and techniques refined in this work will help in the design of more robust reactors as well as validate computational models for licensing sodium fast reactors.

Optical bio-sniffer for ethanol vapor using an oxygen-sensitive optical fiber.

PubMed

Mitsubayashi, Kohji; Kon, Takuo; Hashimoto, Yuki

2003-11-30

An optical bio-sniffer for ethanol was constructed by immobilizing alcohol oxidase (AOD) onto a tip of a fiber optic oxygen sensor with a tube-ring, using an oxygen sensitive ruthenium organic complex (excitation, 470 nm; fluorescent, 600 nm). A reaction unit for circulating buffer solution was applied to the tip of the device. After the experiment in the liquid phase, the sniffer-device was applied for gas analysis using a gas flow measurement system with a gas generator. The optical device was applied to detect the oxygen consumption induced by AOD enzymatic reaction with alcohol application. The sensor in the liquid phase was used to measure ethanol solution from 0.50 to 9.09 mmol/l. Then, the bio-sniffer was calibrated against ethanol vapor from 0.71 to 51.49 ppm with good gas-selectivity based on the AOD substrate specificity. The bio-sniffer with the reaction unit was also used to monitor the concentration change of gaseous ethanol by rinsing and cleaning the fiber tip and the enzyme membrane with buffer solution.

Calibration of soil moisture flow simulation models aided by the active heated fiber optic distributed temperature sensing AHFO

NASA Astrophysics Data System (ADS)

Rodriguez-Sinobas, Leonor; Zubelzu, Sergio; Sobrino, Fernando Fernando; Sánchez, Raúl

2017-04-01

Most of the studies dealing with the development of water flow simulation models in soils, are calibrated using experimental data measured by soil probe sensors or tensiometers which locate at specific points in the study area. However since the beginning of the XXI century, the use of Distributed Fiber Optic Temperature Measurement for estimating temperature variation along a cable of fiber optic has been assessed in multiple environmental applications. Recently, its application combined with an active heating pulses technique (AHFO) has been reported as a sensor to estimate soil moisture. This method applies a known amount of heat to the soil and monitors the temperature evolution, which mainly depends on the soil moisture content. Thus, it allows estimations of soil water content every 12.5 cm along the fiber optic cable, as long as 1500 m , with 2 % accuracy , every second. This study presents the calibration of a soil water flow model (developed in Hydrus 2D) with the AHFO technique. The model predicts the distribution of soil water content of a green area irrigated by sprinkler irrigation. Several irrigation events have been evaluated in a green area located at the ETSI Agronómica, Agroalimentaria y Biosistemas in Madrid where an installation of 147 m of fiber optic cable at 15 cm depth is deployed. The Distribute Temperature Sensing unit was a SILIXA ULTIMA SR (Silixa Ltd, UK) and has spatial and temporal resolution of 0.29 m. Data logged in the DTS unit before, during and after the irrigation event were used to calibrate the estimations in the Hydrus 2D model during the infiltration and redistribution of soil water content within the irrigation interval. References: Karandish, F., & Šimůnek, J. (2016). A field-modeling study for assessing temporal variations of soil-water-crop interactions under water-saving irrigation strategies. Agricultural Water Management, 178, 291-303. Li, Y., Šimůnek, J., Jing, L., Zhang, Z., & Ni, L. (2014). Evaluation of water movement and water losses in a direct-seeded-rice field experiment using Hydrus-1D. Agricultural Water Management, 142, 38-46. Tan, X., Shao, D., & Liu, H. (2014). Simulating soil water regime in lowland paddy fields under different water managements using HYDRUS-1D. Agricultural Water Management, 132, 69-78.

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

NASA Technical Reports Server (NTRS)

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

1991-01-01

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

System for rapid detection of antibiotic resistance of airborne pathogens

NASA Astrophysics Data System (ADS)

Fortin, M.; Noiseux, I.; Mouslinkina, L.; Vernon, M. L.; Laflamme, C.; Filion, G.; Duchaine, C.; Ho, J.

2009-05-01

This project uses function-based detection via a fundamental understanding of the genetic markers of AR to distinguish harmful organisms from innocuous ones. This approach circumvents complex analyses to unravel the taxonomic details of 1399 pathogen species, enormously simplifying detection requirements. Laval Hospital's fast permeabilization strategy enables AR revelation in <1hr. Packaging the AR protocols in liquid-processing cartridges and coupling these to our in-house miniature fiber optic flow cell (FOFC) provides first responders with timely information on-site. INO's FOFC platform consists of a specialty optical fiber through which a hole is transversally bored by laser micromachining. The analyte solution is injected into the hole of the fiber and the particles are detected and counted. The advantage with respect to classic free space FC is that alignment occurs in the fabrication process only and complex excitation and collection optics are replaced by optical fibers. Moreover, we use a sheathless configuration which has the advantage of increase the portability of the system, to reduce excess biohazard material and the need for weekly maintenance. In this paper we present the principle of our FOFC along with a, demonstration of the basic capability of the platform for detection of bacillus cereus spores using permeabilized staining.

Fiber optic microsensor hydrogen leak detection system on Delta IV launch vehicle

NASA Astrophysics Data System (ADS)

Kazemi, Alex A.; Goepp, John W.; Larson, David B.; Wuestling, Mark E.

2008-04-01

This paper describes the successful development and test of a multipoint fiber optic hydrogen microsensors system during the static firing of an Evolved Expandable Launch Vehicle (EELV)/Delta's common booster core (CBC) rocket engine at NASA's Stennis Space Center. The hydrogen sensitive chemistry is fully reversible and has demonstrated a response to hydrogen gas in the range of 0% to 10% with a resolution of 0.1% and a response time of <=5 seconds measured at a gas flow rate of 1 cc/min. The system consisted of a reversible chemical interaction causing a change in reflective of a thin film of coated Palladium. The sensor 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 photodiode detector that synchronously measures the reflected signal. The system incorporates a microprocessor to perform the data analysis and storage, as well as trending and set alarm function. The paper illustrates the sensor design and performance data under field deployment conditions.

Process technologies of MPACVD planar waveguide devices and fiber attachment

NASA Astrophysics Data System (ADS)

Li, Cheng-Chung; Qian, Fan; Boudreau, Robert A.; Rowlette, John R., Sr.; Bowen, Terry P.

1999-03-01

Optical circuits based on low-loss glass waveguide on silicon are a practical and promising approach to integrate different functional components. Fiber attachment to planar waveguide provides a practical application for optical communications. Microwave Plasma Assisted Chemical Vapor Deposition (MPACVD) produces superior quality, low birefringence, low-loss, planar waveguides for integrated optical devices. Microwave plasma initiates the chemical vapor of SiCl4, GeCl4 and oxygen. A Ge-doped silica layer is thus deposited with a compatible high growth rate (i.e. 0.4 - 0.5 micrometer/min). Film properties are based on various parameters, such as chemical flow rates, chamber pressure and temperature, power level and injector design. The resultant refractive index can be varied between 1.46 (i.e. pure silica) and 1.60 (i.e. pure germania). Waveguides can be fabricated with any desired refractive index profile. Standard photolithography defines the waveguide pattern on a mask layer. The core layer is removed by plasma dry etch which has been investigated by both reactive ion etch (RIE) and inductively coupled plasma (ICP) etch. Etch rates of 3000 - 4000 angstrom/min have been achieved using ICP compared to typical etch rates of 200 - 300 angstrom/min using conventional RIE. Planar waveguides offer good mode matching to optical fiber. A polished fiber end can be glued to the end facet of waveguide with a very low optical coupling loss. In addition, anisotropic etching of silicon V- grooves provides a passive alignment capability. Epoxy and solder were used to fix the fiber within the guiding groove. Several designs of waveguide-fiber attachment will be discussed.

Optical spectral sweep comb liquid flow rate sensor.

PubMed

Shen, Changyu; Lian, Xiaokang; Kavungal, Vishnu; Zhong, Chuan; Liu, Dejun; Semenova, Yuliya; Farrell, Gerald; Albert, Jacques; Donegan, John F

2018-02-15

In microfluidic chip applications, the flow rate plays an important role. Here we propose a simple liquid flow rate sensor by using a tilted fiber Bragg grating (TFBG) as the sensing element. As the water flows in the vicinity of the TFBG along the fiber axis direction, the TFBG's spectrum changes due to its contact with water. By comparing the time-swept spectra of the TFBG in water to that of the TFBG with water flowing over it, a spectral sweep comb was formed, and the flow rate can be detected by selecting a suitable sweeping frequency. The proposed sensor has a high Q-value of over 17,000 for the lower rate and a large detectable range from 0.0058 mm/s to 3.2 mm/s. And the calculated corresponding lower detectable flow rate of 0.03 nL/s is 3 orders magnitude better than that of the current fiber flowmeter. Meanwhile, the proposed sensor has the temperature self-compensation function for the variation of the external temperature. We believe that this simple configuration will open a research direction of the TFBG-deriving theory and configuration for lower flow rate measurements for microfluidic chip applications.

Miniaturized flow injection analysis system

DOEpatents

Folta, J.A.

1997-07-01

A chemical analysis technique known as flow injection analysis is described, wherein small quantities of chemical reagents and sample are intermixed and reacted within a capillary flow system and the reaction products are detected optically, electrochemically, or by other means. A highly miniaturized version of a flow injection analysis system has been fabricated utilizing microfabrication techniques common to the microelectronics industry. The microflow system uses flow capillaries formed by etching microchannels in a silicon or glass wafer followed by bonding to another wafer, commercially available microvalves bonded directly to the microflow channels, and an optical absorption detector cell formed near the capillary outlet, with light being both delivered and collected with fiber optics. The microflow system is designed mainly for analysis of liquids and currently measures 38{times}25{times}3 mm, but can be designed for gas analysis and be substantially smaller in construction. 9 figs.

Doppler Global Velocimetry at NASA Glenn Research Center: System Discussion and Results

NASA Technical Reports Server (NTRS)

Lant, Christian T.

2003-01-01

A ruggedized Doppler Global Velocimetry system has been built and tested at NASA Glenn Research Center. One component of planar velocity measurements of subsonic and supersonic flows from an under-expanded free jet are reported, which agree well with predicted values. An error analysis evaluates geometric and spectral error terms, and characterizes speckle noise in isotropic data. A multimode, fused fiber optic bundle is demonstrated to couple up to 650 mJ/pulse of laser light without burning or fiber ablation, and without evidence of Stimulated Brillouin Scattering or other spectral-broadening problems. Comparisons are made between spinning wheel data using illumination by freespace beam propagation and fiber optic beam delivery. The fiber bundle illumination is found to provide more spatially even and stable illumination than is typically available from pulsed Nd:YAG laser beams. The fiber bundle beam delivery is also a step toward making remote measurements and automatic real-time plume sectioning feasible in wind tunnel environments.

Application of new electro-optic technology to Space Station Freedom data management system

NASA Technical Reports Server (NTRS)

Husbands, C. R.; Girard, M. M.

1993-01-01

A low risk design methodology to permit the local bus structures to support increased data carrying capacities and to speed messages and data flow between nodes or stations on the Space Station Freedom Data Management System in anticipation of growing requirements was evaluated and recommended. The recommended design employs a collateral fiber optic technique that follows a NATO avionic standard that is developed, tested, and available. Application of this process will permit a potential 25 fold increase in data transfer performance on the local wire bus network with a fiber optic network, maintaining the functionality of the low-speed bus and supporting all of the redundant transmission and fault detection capabilities designed into the existing system. The application of wavelength division multiplexing (WDM) technology to both the local data bus and global data bus segments of the Data Management System to support anticipated additional highspeed data transmission requirements was also examined. Techniques were examined to provide a dual wavelength implementation of the fiber optic collateral networks. This dual wavelength implementation would permit each local bus to support two simultaneous high-speed transfers on the same fiber optic bus structure and operate within the limits of the existing protocol standard. A second WDM study examined the use of spectral sliced technology to provide a fourfold increase in the Fiber Distributed Data Interface (FDDI) global bus networks without requiring modifications to the existing installed cable plant. Computer simulations presented indicated that this data rate improvement can be achieved with commercially available optical components.

Fiber optic suctioning of urinary stone phantoms during laser lithotripsy

NASA Astrophysics Data System (ADS)

Blackmon, Richard L.; Case, Jason R.; Trammell, Susan R.; Irby, Pierce B.; Fried, Nathaniel M.

2013-03-01

Fiber optic attraction of urinary stones during laser lithotripsy has been previously observed, and this phenomenon may potentially be exploited to pull stones inside the urinary tract without mechanical grasping tools, thus saving the urologist valuable time and space in the ureteroscope's single working channel. In this study, Thulium fiber laser (TFL) high-pulse-rate/low-pulse-energy operation and Holmium:YAG low-pulse-rate/high-pulse-energy operation are compared for fiber optic "suctioning" of Plaster-of-Paris stone phantoms. A TFL with wavelength of 1908 nm, pulse energy of 35 mJ, pulse duration of 500 μs, and pulse rate of 10-350 Hz, and Holmium laser with wavelength of 2120 nm, pulse energy of 35-360 mJ, pulse duration of 300 μs, and pulse rate of 20 Hz were tested using 270-μm-core fibers. A peak "pull" speed of 2.5 mm/s was measured for both TFL (35 mJ and 150-250 Hz) and Holmium laser (210 mJ and 20 Hz). Particle image velocimetry and thermal imaging were used to track water flow for all parameters. Fiber optic suctioning of urinary stone phantoms is feasible for both lasers. However, TFL operation at high-pulse-rates/low-pulse-energies provides faster, smoother stone pulling than Holmium operation at low-pulserates/ high-pulse-energies. After further study, this method may be used to manipulate urinary stones in the clinic.

Continuous glucose determination using fiber-based tunable mid-infrared laser spectroscopy

NASA Astrophysics Data System (ADS)

Yu, Songlin; Li, Dachao; Chong, Hao; Sun, Changyue; Xu, Kexin

2014-04-01

Wavelength-tunable laser spectroscopy in combination with a small-sized fiber-optic attenuated total reflection (ATR) sensor (fiber-based evanescent field analysis, FEFA) is reported for the continuous measurement of the glucose level. We propose a method of controlling and stabilizing the wavelength and power of laser emission and present a newly developed mid-infrared wavelength-tunable laser with a broad emission spectrum band of 9.19-9.77 μm (1024-1088 cm-1). The novel small-sized flow-through fiber-optic ATR sensor with long optical sensing length was used for glucose level determination. The experimental results indicate that the noise-equivalent concentration of this laser measurement system is as low as 3.8 mg/dL, which is among the most precise glucose measurements using mid-infrared spectroscopy. The sensitivity, which is three times that of conventional Fourier transform infrared spectrometer, was acquired because of the higher laser power and higher spectral resolution. The best prediction of the glucose concentration in phosphate buffered saline solution was achieved using the five-variable partial least-squares model, yielding a root-mean-square error of prediction as small as 3.5 mg/dL. The high sensitivity, multiple tunable wavelengths and small fiber-based sensor with long optical sensing length make glucose determination possible in blood or interstitial fluid in vivo.

Microprobes For Blood Flow Measurements In Tissue And Small Vessels

NASA Astrophysics Data System (ADS)

Oberg, P. A.; Salerud, E. G.

1988-04-01

Laser Doppler flowmetry is a method for the continuous and non-invasive recording of tissue blood flow. The method has already proved to be advantageous in a number of clinical as well as theoretical medical disciplines. In dermatology, plastic- and gastrointestinal surgery laser Doppler measurements have substantially contributed to increase knowledge of microvascular perfusion. In experimental medicine, the method has been used in the study of a great variety of microvascular problems. Spontaneous rhythmical variations, spatial and temporal fluctuations in human skin blood flow are mentioned as examples of problem areas in which new knowledge has been generated. The method has facilitated further investigations of the nature of spongeous bone blood flow, testis and kidney cortex blood flow. Recently we have showed that a variant of the laser Doppler method principle, using a single optical fiber, can be advantageous in deep tissue measurements. With this method laser light is transmitted bidirectionally in a single fiber. The tissue trauma which affects blood flow can be minimized by introducing small diameter fibers (0.1-0.5 mm). A special set-up utilizing the same basic principle has been used for the recording of blood flow in small vessels.

Integrated fiber optical and thermal sensor for noninvasive monitoring of blood and human tissue

NASA Astrophysics Data System (ADS)

Saetchnikov, Vladimir A.; Tcherniavskaia, Elina A.; Schiffner, Gerhard

2007-05-01

A novel concept of noninvasive monitoring of human tissue and blood based on optical diffuse reflective spectroscopy combined with metabolic heat measurements has been under development. A compact integrated fiber optical and thermal sensor has been developed. The idea of the method was to evaluate by optical spectroscopy haemoglobin and derivative concentrations and supplement with data associated with the oxidative metabolism of glucose. Body heat generated by glucose oxidation is based on the balance of capillary glucose and oxygen supply to the cells. The variation in glucose concentration is followed also by a difference from a distance (or depth) of scattered through the body radiation. So, blood glucose can be estimated by measuring the body heat and the oxygen supply. The sensor pickup contains of halogen lamp and LEDs combined with fiber optical bundle to deliver optical radiation inside and through the patient body, optical and thermal detectors. Fiber optical probe allows diffuse scattering measurement down to a depth of 2.5 mm in the skin including vascular system, which contributes to the control of the body temperature. The sensor pickup measures thermal generation, heat balance, blood flow rate, haemoglobin and derivative concentrations, environmental conditions. Multivariate statistical analysis was applied to convert various signals from the sensor pickup into physicochemical variables. By comparing the values from the noninvasive measurement with the venous plasma result, analytical functions for patient were obtained. Cluster analysis of patient groups was used to simplify a calibration procedure. Clinical testing of developed sensor is being performed.

Demonstration of a Fiber Optic Regression Probe in a High-Temperature Flow

NASA Technical Reports Server (NTRS)

Korman, Valentin; Polzin, Kurt

2011-01-01

The capability to provide localized, real-time monitoring of material regression rates in various applications has the potential to provide a new stream of data for development testing of various components and systems, as well as serving as a monitoring tool in flight applications. These applications include, but are not limited to, the regression of a combusting solid fuel surface, the ablation of the throat in a chemical rocket or the heat shield of an aeroshell, and the monitoring of erosion in long-life plasma thrusters. The rate of regression in the first application is very fast, while the second and third are increasingly slower. A recent fundamental sensor development effort has led to a novel regression, erosion, and ablation sensor technology (REAST). The REAST sensor allows for measurement of real-time surface erosion rates at a discrete surface location. The sensor is optical, using two different, co-located fiber-optics to perform the regression measurement. The disparate optical transmission properties of the two fiber-optics makes it possible to measure the regression rate by monitoring the relative light attenuation through the fibers. As the fibers regress along with the parent material in which they are embedded, the relative light intensities through the two fibers changes, providing a measure of the regression rate. The optical nature of the system makes it relatively easy to use in a variety of harsh, high temperature environments, and it is also unaffected by the presence of electric and magnetic fields. In addition, the sensor could be used to perform optical spectroscopy on the light emitted by a process and collected by fibers, giving localized measurements of various properties. The capability to perform an in-situ measurement of material regression rates is useful in addressing a variety of physical issues in various applications. An in-situ measurement allows for real-time data regarding the erosion rates, providing a quick method for empirically anchoring any analysis geared towards lifetime qualification. Erosion rate data over an operating envelope could also be useful in the modeling detailed physical processes. The sensor has been embedded in many regressing media to demonstrate the capabilities in a number of regressing environments. In the present work, sensors were installed in the eroding/regressing throat region of a converging-diverging flow, with the working gas heated to high temperatures by means of a high-pressure arc discharge at steady-state discharge power levels up to 500 kW. The amount of regression observed in each material sample was quantified using a later profilometer, which was compared to the in-situ erosion measurements to demonstrate the efficacy of the measurement technique in very harsh, high-temperature environments.

Doppler imaging using spectrally-encoded endoscopy

PubMed Central

Yelin, Dvir; Bouma, B. E.; Rosowsky, J. J.; Tearney, G. J.

2009-01-01

The capability to image tissue motion such as blood flow through an endoscope could have many applications in medicine. Spectrally encoded endoscopy (SEE) is a recently introduced technique that utilizes a single optical fiber and miniature diffractive optics to obtain endoscopic images through small diameter probes. Using spectral-domain interferometry, SEE is furthermore capable of three-dimensional volume imaging at video rates. Here we show that by measuring relative spectral phases, this technology can additionally measure Doppler shifts. Doppler SEE is demonstrated in flowing Intralipid phantoms and vibrating middle ear ossicles. PMID:18795020

Optical fiber extrinsic Fabry-Perot interferometric (EFPI)-based biosensors

NASA Astrophysics Data System (ADS)

Elster, Jennifer L.; Jones, Mark E.; Evans, Mishell K.; Lenahan, Shannon M.; Boyce, Christopher A.; Velander, William H.; VanTassell, Roger

2000-05-01

A novel system incorporating optical fiber extrinsic Fabry- Perot interferometric (EFPI)-based sensors for rapid detection of biological targets is presented. With the appropriate configuration, the EFPI senor is able to measure key environmental parameters by monitoring the interferometric fringes resulting from an optical path differences of reflected signals. The optical fiber EFPI sensor has been demonstrated for strain, pressure, and temperature measurements and can be readily modified for refractive index measurements by allowing solutions to flow into an open cavity. The sensor allows for highly sensitive, real-time, refractive index measurements and by applying affinity coatings containing ligands within this cavity, specific binding of target molecules can be accomplished. As target molecules bind to the coating, there is an increased density within the film, causing a measurable refractive index change that correlates to the concentration of detected target molecules. This sensor platform offers enhanced sensing capabilities for clinical diagnostics, pharmaceutical screening, environmental monitoring, food pathogen detection, biological warfare agent detection, and industrial bioprocessing. Promising applications also exist for process monitoring within the food/beverage, petroleum, and chemical industry.

High-Resolution Digital Two-Color PIV for Turbomachinery Flows

NASA Astrophysics Data System (ADS)

Copenhaver, W.; Gogineni, S.; Goss, L.

1996-11-01

Turbomachinery flows are inherently unsteady. However, steady design methods are currently used to develop turbomachinery, with the lack of basic understanding of unsteady effects being compensated by use of extensive empirical correlations. Conventional laser anemometry provides quantitative evidence of unsteady effects in turbomachinery but is limited in fully exploring this phenomenon. The PIV technique holds great promise for elucidating unsteady flow mechanisms in turbomachinery if obstacles to its application in a transonic turbomachine can be overcome. Implementation involves critical issues such as tracer seeding and optical access for transmitter and receiver. Initially, an 18-in.-dia. axial fan is used to explore these issues. One optical configuration considered is the fiber-optic fanning light sheet in conjunction with high-power pulsed lasers. Instantaneous velocity measurements are made between blades at different spanwise locations.

Cross layer optimization for cloud-based radio over optical fiber networks

NASA Astrophysics Data System (ADS)

Shao, Sujie; Guo, Shaoyong; Qiu, Xuesong; Yang, Hui; Meng, Luoming

2016-07-01

To adapt the 5G communication, the cloud radio access network is a paradigm introduced by operators which aggregates all base stations computational resources into a cloud BBU pool. The interaction between RRH and BBU or resource schedule among BBUs in cloud have become more frequent and complex with the development of system scale and user requirement. It can promote the networking demand among RRHs and BBUs, and force to form elastic optical fiber switching and networking. In such network, multiple stratum resources of radio, optical and BBU processing unit have interweaved with each other. In this paper, we propose a novel multiple stratum optimization (MSO) architecture for cloud-based radio over optical fiber networks (C-RoFN) with software defined networking. Additionally, a global evaluation strategy (GES) is introduced in the proposed architecture. MSO can enhance the responsiveness to end-to-end user demands and globally optimize radio frequency, optical spectrum and BBU processing resources effectively to maximize radio coverage. The feasibility and efficiency of the proposed architecture with GES strategy are experimentally verified on OpenFlow-enabled testbed in terms of resource occupation and path provisioning latency.

Boundary Layer Measurements in a Supersonic Wind Tunnel Using Doppler Global Velocimetry

NASA Technical Reports Server (NTRS)

Meyers, James F.; Lee, Joseph W.; Cavone, Angelo A.

2010-01-01

A modified Doppler Global Velocimeter (DGV) was developed to measure the velocity within the boundary layer above a flat plate in a supersonic flow. Classic laser velocimetry (LV) approaches could not be used since the model surface was composed of a glass-ceramic insulator in support of heat-transfer measurements. Since surface flare limited the use of external LV techniques and windows placed in the model would change the heat transfer characteristics of the flat plate, a novel approach was developed. The input laser beam was divided into nine equal power beams and each transmitted through optical fibers to a small cavity within the model. The beams were then directed through 1.6-mm diameter orifices to form a series of orthogonal beams emitted from the model and aligned with the tunnel centerline to approximate a laser light sheet. Scattered light from 0.1-micron diameter water condensation ice crystals was collected by four 5-mm diameter lenses and transmitted by their respective optical fiber bundles to terminate at the image plane of a standard two-camera DGV receiver. Flow measurements were made over a range from 0.5-mm above the surface to the freestream at Mach 3.51 in steady state and heat pulse injected flows. This technique provides a unique option for measuring boundary layers in supersonic flows where seeding the flow is problematic or where the experimental apparatus does not provide the optical access required by other techniques.

Investigation of optical fibers for gas-phase, ultraviolet laser-induced-fluorescence (UV-LIF) spectroscopy.

PubMed

Hsu, Paul S; Kulatilaka, Waruna D; Jiang, Naibo; Gord, James R; Roy, Sukesh

2012-06-20

We investigate the feasibility of transmitting high-power, ultraviolet (UV) laser pulses through long optical fibers for laser-induced-fluorescence (LIF) spectroscopy of the hydroxyl radical (OH) and nitric oxide (NO) in reacting and non-reacting flows. The fundamental transmission characteristics of nanosecond (ns)-duration laser pulses are studied at wavelengths of 283 nm (OH excitation) and 226 nm (NO excitation) for state-of-the-art, commercial UV-grade fibers. It is verified experimentally that selected fibers are capable of transmitting sufficient UV pulse energy for single-laser-shot LIF measurements. The homogeneous output-beam profile resulting from propagation through a long multimode fiber is ideal for two-dimensional planar-LIF (PLIF) imaging. A fiber-coupled UV-LIF system employing a 6 m long launch fiber is developed for probing OH and NO. Single-laser-shot OH- and NO-PLIF images are obtained in a premixed flame and in a room-temperature NO-seeded N(2) jet, respectively. Effects on LIF excitation lineshapes resulting from delivering intense UV laser pulses through long fibers are also investigated. Proof-of-concept measurements demonstrated in the current work show significant promise for fiber-coupled UV-LIF spectroscopy in harsh diagnostic environments such as gas-turbine test beds.

Chemical, biochemical, and environmental fiber sensors III; Proceedings of the Meeting, Boston, MA, Sept. 4, 5, 1991

NASA Astrophysics Data System (ADS)

Lieberman, Robert A.

Various papers on chemical, biochemical, and environmental fiber sensors are presented. Individual topics addressed include: fiber optic pressure sensor for combustion monitoring and control, viologen-based fiber optic oxygen sensors, renewable-reagent fiber optic sensor for ocean pCO2, transition metal complexes as indicators for a fiber optic oxygen sensor, fiber optic pH measurements using azo indicators, simple reversible fiber optic chemical sensors using solvatochromic dyes, totally integrated optical measuring sensors, integrated optic biosensor for environmental monitoring, radiation dosimetry using planar waveguide sensors, optical and piezoelectric analysis of polymer films for chemical sensor characterization, source polarization effects in an optical fiber fluorosensor, lens-type refractometer for on-line chemical analysis, fiber optic hydrocarbon sensor system, chemical sensors for environmental monitoring, optical fibers for liquid-crystal sensing and logic devices, suitability of single-mode fluoride fibers for evanescent-wave sensing, integrated modules for fiber optic sensors, optoelectronic sensors based on narrowband A3B5 alloys, fiber Bragg grating chemical sensor.

Concentric core optical fiber with multiple-mode signal transmission

DOEpatents

Muhs, J.D.

1997-05-06

A concentric core optical fiber provides for the simultaneous but independent transmission of signals over a single optical fiber. The concentric optical fiber is constructed of a single-mode or multimode inner optical fiber defined by a core and a cladding of a lower index of refraction than the core and an outer optical fiber defined by additional cladding concentrically disposed around the cladding and of an index of refraction lower than the first mentioned cladding whereby the latter functions as the core of the outer optical fiber. By employing such an optical fiber construction with a single-mode inner core or optical fiber, highly sensitive interferometric and stable less sensitive amplitude based sensors can be placed along the same length of a concentric core optical fiber. Also, by employing the concentric core optical fiber secure telecommunications can be achieved via the inner optical fiber since an intrusion of the concentric optical fiber will first cause a variation in the light being transmitted through the outer optical fiber and this variation of light being used to trigger a suitable alarm indicative of the intrusion. 3 figs.

Concentric core optical fiber with multiple-mode signal transmission

DOEpatents

Muhs, Jeffrey D.

1997-01-01

A concentric core optical fiber provides for the simultaneous but independent transmission of signals over a single optical fiber. The concentric optical fiber is constructed of a single-mode or multimode inner optical fiber defined by a core and a cladding of a lower index of refraction than the core and an outer optical fiber defined by additional cladding concentrically disposed around the cladding and of an index of refraction lower than the first mentioned cladding whereby the latter functions as the core of the outer optical fiber. By employing such an optical fiber construction with a single-mode inner core or optical fiber, highly sensitive interferometric and stable less sensitive amplitude based sensors can be placed along the same length of a concentric core optical fiber. Also, by employing the concentric core optical fiber secure telecommunications can be achieved via the inner optical fiber since an intrusion of the concentric optical fiber will first cause a variation in the light being transmitted through the outer optical fiber and this variation of light being used to trigger a suitable alarm indicative of the intrusion.

A compact tunable diode laser absorption spectrometer to monitor CO2 at 2.7 μm wavelength in hypersonic flows.

PubMed

Vallon, Raphäel; Soutadé, Jacques; Vérant, Jean-Luc; Meyers, Jason; Paris, Sébastien; Mohamed, Ajmal

2010-01-01

Since the beginning of the Mars planet exploration, the characterization of carbon dioxide hypersonic flows to simulate a spaceship's Mars atmosphere entry conditions has been an important issue. We have developed a Tunable Diode Laser Absorption Spectrometer with a new room-temperature operating antimony-based distributed feedback laser (DFB) diode laser to characterize the velocity, the temperature and the density of such flows. This instrument has been tested during two measurement campaigns in a free piston tunnel cold hypersonic facility and in a high enthalpy arc jet wind tunnel. These tests also demonstrate the feasibility of mid-infrared fiber optics coupling of the spectrometer to a wind tunnel for integrated or local flow characterization with an optical probe placed in the flow.

Development and utilization of new diagnostics for dense-phase pneumatic transport. Quarterly technical progress report, October 1-December 31, 1989

DOE Office of Scientific and Technical Information (OSTI.GOV)

Louge, M. Y.; Jenkins, J. T.

The main objective of this work is to develop probes for local measurements of solid velocity and holdup in dense gas-solid flows. In particular, capacitance probes are designed to measure local, time-dependent particle concentrations. In addition, a new optical fiber probe based on laser-induced-phosphorescence is developed to measure particle velocities. The principles for the capacitance and optical diagnostics were given in our first and second quarterly reports. In this reporting period, we have demonstrated with success the feasibility of the optical fiber probe. Another objective of this work is to develop a model of dense-phase conveying and to test thismore » model in a setup that incorporates our diagnostics. In this period, as a prelude to these modeling efforts scheduled for the third year of the contract, we have carried out additional computer simulations of rapid granular flows to verify the theories of Jenkins and Richman (1988) on the anisotropy of the second moment in simple shear. 2 refs., 5 figs.« less

Report on Technology Horizons: A Vision for Air Force Science and Technology During 2010-2030. Volume 1

DTIC Science & Technology

2010-05-15

flow and decision processes across the air and space domains. It thus comprises traditional wired and fiber-optic computer networks based on...dual flow path design allow high volumetric efficiency, and high cruise speed provides significantly increased survivability. Vertical takeoff...emerging “third-stream engine architectures” can enable for constant mass flow engines that can provide further reductions in fuel consumption. A wide

KSC-02pd1131

NASA Image and Video Library

2002-07-10

KENNEDY SPACE CENTER, FLA. -- Scott Minnick, with United Space Alliance, places a fiber-optic camera inside the flow line on Endeavour. Minnick wears a special viewing apparatus that sees where the camera is going. The inspection is the result of small cracks being discovered on the LH2 Main Propulsion System (MPS) flow liners in other orbiters. Endeavour is next scheduled to fly on mission STS-113.

KSC-02pd1128

NASA Image and Video Library

2002-07-10

KENNEDY SPACE CENTER, FLA. -- Scott Minnick, with United Space Alliance, places a fiber-optic camera inside the flow line on Endeavour. Minnick wears a special viewing apparatus that sees where the camera is going. The inspection is the result of small cracks being discovered on the LH2 Main Propulsion System (MPS) flow liners in other orbiters. Endeavour is next scheduled to fly on mission STS-113.

Steady State Pyrolysis and Ablation Investigation

DTIC Science & Technology

2008-03-31

the heat flux rises with increased transpiration mass flow. For mass 0.050 0.075 Mass flow [g/s] Figure 1.5: Heat flux with and without chocking ...initial species are N2 and 02- As the flow passes through the shock wave surrounding the body, additional species are produced by dis- sociation and...which images the plasma flow after a second reflect on a flat mirror on the entrance of an optical fiber. The captured light is then sent to an Ocean

Novel fiber-based technique for inspection of holes in narrow-bore tubes

NASA Astrophysics Data System (ADS)

Bernard, Fabien; Flaherty, Tony; O'Connor, Gerard M.

2009-06-01

Optical tools offer a route to increasing throughput and efficiency in industrial inspection operations, one of the most time-consuming and labour-intensive aspects of modern manufacturing. One prominent example in the medical device industry is inspection of drilled holes, particularly in narrow-bore tubes (precision-flow devices, such as catheters for drug delivery, radio-opaque contrast agents, etc). The products in which these holes feature are increasing in complexity (reduced dimensions, increasing number of drilled features- in some products now reaching into the hundreds). These trends present a number of technical challenges, not least to ensure that holes are completed and that no damage to the part occurs as a result of over-drilling, for example. This paper will present a novel sensor based on back-side illumination of the drilled hole using side-glowing optical fibers to detect, qualify and quantify drilled holes. The concept is based on inserting a laser-coupled side-glowing optical fiber into the lumen of the tube to be drilled, and imaging the light emitted from this fiber through a drilled hole using a vision system mounted external to the tube. The light from the fiber allows rapid determination of hole completion, shape and size, as well as quantity in the case of products with multiple holes. If the fiber is mounted in the tube prior to drilling, the light emitted from the fiber can be used as a real-time hole breakthrough sensor, preventing under or overdrilling of the tube.

Tapered Glass-Fiber Microspike: High-Q Flexural Wave Resonator and Optically Driven Knudsen Pump.

PubMed

Pennetta, Riccardo; Xie, Shangran; Russell, Philip St J

2016-12-30

Appropriately designed optomechanical devices are ideal for making ultra-sensitive measurements. Here we report a fused-silica microspike that supports a flexural resonance with a quality factor greater than 100 000 at room temperature in vacuum. Fashioned by tapering single-mode fiber (SMF), it is designed so that the core-guided optical mode in the SMF evolves adiabatically into the fundamental mode of the air-glass waveguide at the tip. The very narrow mechanical linewidth (20 mHz) makes it possible to measure extremely small changes in resonant frequency. In a vacuum chamber at low pressure, the weak optical absorption of the glass is sufficient to create a temperature gradient along the microspike, which causes it to act as a microscopic Knudsen pump, driving a flow of gas molecules towards the tip where the temperature is highest. The result is a circulating molecular flow within the chamber. Momentum exchange between the vibrating microspike and the flowing molecules causes an additional restoring force that can be measured as a tiny shift in the resonant frequency. The effect is strongest when the mean free path of the gas molecules is comparable with the dimensions of the vacuum chamber. The system offers a novel means of monitoring the behavior of weakly absorbing optomechanical sensors operating in vacuum.

An optical probe for local measurements of fast plasma ion dynamics

NASA Astrophysics Data System (ADS)

Fiksel, G.; Den Hartog, D. J.; Fontana, P. W.

1998-05-01

A novel insertable probe for local measurements of equilibrium and fluctuating plasma ion flow velocity and temperature via Doppler spectroscopy is described. Optical radiation is collected by two fused silica fiber optic bundles with perpendicular viewlines. Spatial resolution of about 5 cm is achieved by terminating each view with an optical dump. The collected light is transported by the fiber bundles to a high-resolution spectrometer. Two components of the velocity are measured simultaneously—the radial along the insertion of the probe and a perpendicular component (which can be varied by simply rotating the probe by 90°). The accuracy of the velocity measurements is better than 1 km/s. The probe is armored by a boron nitride enclosure and is inserted into a high temperature plasma to obtain radial profiles of the equilibrium and fluctuating plasma velocity. Initial measurements have been done in Madison Symmetric Torus reversed field pinch.

Laser restoration of flow in occluded ventricular shunts for pediatric neurosurgery

NASA Astrophysics Data System (ADS)

Christens-Barry, William A.; Guarnieri, Michael; Carson, Benjamin S.

1998-01-01

We have investigated the use of short pulses of infrared ((lambda) equals 2.09 micrometers ) light from a Ho:YAG laser to photofragment occlusions and restore flow in ventricular shunts, which provide the sole means of maintaining proper intracranial pressure in hydrocephalus patients. These experiments employed model tissues, a polymeric model compound, and patient explants in order to determine appropriate pulse energies and delivery rates for removal of occlusions material. Laser energy doses and rates of occlusion removal were established for these materials. Laser energy doses that do not damage the shunt device or surrounding tissue were identified. Optical fibers (25 ga. or smaller) can be introduced through the dome of current shunt devices and threaded to the occlusion site. Clinical application will require the continued development of an introducer tool for the transcutaneous insertion of the optical fiber into the shunt device and irrigation techniques for removing the occlusion detritus generated by photofragmentation treatment. Using this approach, a minimally invasive and benign procedure for in situ restoration of flow in occluded neurological implant devices becomes possible.

A hybrid optical switch architecture to integrate IP into optical networks to provide flexible and intelligent bandwidth on demand for cloud computing

NASA Astrophysics Data System (ADS)

Yang, Wei; Hall, Trevor J.

2013-12-01

The Internet is entering an era of cloud computing to provide more cost effective, eco-friendly and reliable services to consumer and business users. As a consequence, the nature of the Internet traffic has been fundamentally transformed from a pure packet-based pattern to today's predominantly flow-based pattern. Cloud computing has also brought about an unprecedented growth in the Internet traffic. In this paper, a hybrid optical switch architecture is presented to deal with the flow-based Internet traffic, aiming to offer flexible and intelligent bandwidth on demand to improve fiber capacity utilization. The hybrid optical switch is capable of integrating IP into optical networks for cloud-based traffic with predictable performance, for which the delay performance of the electronic module in the hybrid optical switch architecture is evaluated through simulation.

Process and Structural Health Monitoring of Composite Structures with Embedded Fiber Optic Sensors and Piezoelectric Transducers

NASA Astrophysics Data System (ADS)

Keulen, Casey James

Advanced composite materials are becoming increasingly more valuable in a plethora of engineering applications due to properties such as tailorability, low specific strength and stiffness and resistance to fatigue and corrosion. Compared to more traditional metallic and ceramic materials, advanced composites such as carbon, aramid or glass reinforced plastic are relatively new and still require research to optimize their capabilities. Three areas that composites stand to benefit from improvement are processing, damage detection and life prediction. Fiber optic sensors and piezoelectric transducers show great potential for advances in these areas. This dissertation presents the research performed on improving the efficiency of advanced composite materials through the use of embedded fiber optic sensors and surface mounted piezoelectric transducers. Embedded fiber optic sensors are used to detect the presence of resin during the injection stage of resin transfer molding, monitor the degree of cure and predict the remaining useful life while in service. A sophisticated resin transfer molding apparatus was developed with the ability of embedding fiber optics into the composite and a glass viewing window so that resin flow sensors could be verified visually. A novel technique for embedding optical fiber into both 2- and 3-D structures was developed. A theoretical model to predict the remaining useful life was developed and a systematic test program was conducted to verify this model. A network of piezoelectric transducers was bonded to a composite panel in order to develop a structural health monitoring algorithm capable of detecting and locating damage in a composite structure. A network configuration was introduced that allows for a modular expansion of the system to accommodate larger structures and an algorithm based on damage progression history was developed to implement the network. The details and results of this research are contained in four manuscripts that are included in Appendices A-D while the body of the dissertation provides background information and a summary of the results.

Computational analysis of the effectiveness of blood flushing with saline injection from an intravascular diagnostic catheter

PubMed Central

Ghata, Narugopal; Aldredge, Ralph C.; Bec, Julien; Marcu, Laura

2015-01-01

SUMMARY Optical techniques including fluorescence lifetime spectroscopy have demonstrated potential as a tool for study and diagnosis of arterial vessel pathologies. However, their application in the intravascular diagnostic procedures has been hampered by the presence of blood hemoglobin that affects the light delivery to and the collection from the vessel wall. We report a computational fluid dynamics model that allows for the optimization of blood flushing parameters in a manner that minimizes the amount of saline needed to clear the optical field of view and reduces any adverse effects caused by the external saline jet. A 3D turbulence (k−ω) model was employed for Eulerian–Eulerian two-phase flow to simulate the flow inside and around a side-viewing fiber-optic catheter. Current analysis demonstrates the effects of various parameters including infusion and blood flow rates, vessel diameters, and pulsatile nature of blood flow on the flow structure around the catheter tip. The results from this study can be utilized in determining the optimal flushing rate for given vessel diameter, blood flow rate, and maximum wall shear stress that the vessel wall can sustain and subsequently in optimizing the design parameters of optical-based intravascular catheters. PMID:24953876

Metal-Coated Optical Fibers for High Temperature Applications

NASA Technical Reports Server (NTRS)

Zeakes, Jason; Murphy, Kent; Claus, Richard; Greene, Jonathan; Tran, Tuan

1996-01-01

This poster will highlight on-going research at the Virginia Tech Fiber & Electro-Optics Research Center (FEORC) in the area of thin films on optical fibers. Topics will include the sputter deposition of metals and metal; alloys onto optical fiber and fiber optic sensors for innovative applications. Specific information will be available on thin film fiber optic hydrogen sensors, corrosion sensors, and metal-coated optical fiber for high temperature aerospace applications.

Fiber optics: A research paper

NASA Technical Reports Server (NTRS)

Drone, Melinda M.

1987-01-01

Some basic aspects concerning fiber optics are examined. Some history leading up to the development of optical fibers which are now used in the transmission of data in many areas of the world is discussed. Basic theory of the operation of fiber optics is discussed along with methods for improving performance of the optical fiber through much research and design. Splices and connectors are compared and short haul and long haul fiber optic networks are discussed. Fiber optics plays many roles in the commercial world. The use of fiber optics for communication applications is emphasized.

Fiber optic connector

DOEpatents

Rajic, Slobodan; Muhs, Jeffrey D.

1996-01-01

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

Mass-manufacturable polymer microfluidic device for dual fiber optical trapping.

PubMed

De Coster, Diane; Ottevaere, Heidi; Vervaeke, Michael; Van Erps, Jürgen; Callewaert, Manly; Wuytens, Pieter; Simpson, Stephen H; Hanna, Simon; De Malsche, Wim; Thienpont, Hugo

2015-11-30

We present a microfluidic chip in Polymethyl methacrylate (PMMA) for optical trapping of particles in an 80µm wide microchannel using two counterpropagating single-mode beams. The trapping fibers are separated from the sample fluid by 70µm thick polymer walls. We calculate the optical forces that act on particles flowing in the microchannel using wave optics in combination with non-sequential ray-tracing and further mathematical processing. Our results are compared with a theoretical model and the Mie theory. We use a novel fabrication process that consists of a premilling step and ultraprecision diamond tooling for the manufacturing of the molds and double-sided hot embossing for replication, resulting in a robust microfluidic chip for optical trapping. In a proof-of-concept demonstration, we show the trapping capabilities of the hot embossed chip by trapping spherical beads with a diameter of 6µm, 8µm and 10µm and use the power spectrum analysis of the trapped particle displacements to characterize the trap strength.

Optical monitoring of thin film electro-polymerization on surface of ITO-coated lossy-mode resonance sensor

NASA Astrophysics Data System (ADS)

Sobaszek, Michał; Dominik, Magdalena; Burnat, Dariusz; Bogdanowicz, Robert; Stranak, Viteszlav; Sezemsky, Petr; Śmietana, Mateusz

2017-04-01

This work presents an optical fiber sensors based on lossy-mode resonance (LMR) phenomenon supported by indium tin oxide (ITO) thin overlay for investigation of electro-polymerization effect on ITO's surface. The ITO overlays were deposited on core of polymer-clad silica (PCS) fibers using reactive magnetron sputtering (RMS) method. Since ITO is electrically conductive and electrochemically active it can be used as a working electrode in 3-electrode cyclic voltammetry setup. For fixed potential applied to the electrode current flow decrease with time what corresponds to polymer layer formation on the ITO surface. Since LMR phenomenon depends on optical properties in proximity of the ITO surface, polymer layer formation can be monitored optically in real time. The electrodeposition process has been performed with Isatin which is a strong endogenous neurochemical regulator in humans as it is a metabolic derivative of adrenaline. It was found that optical detection of Isatin is possible in the proposed configuration.

All Fiber-Coupled OH Planar Laser-Induced-Fluorescence (OH-PLIF)-Based Two-Dimensional Thermometry.

PubMed

Hsu, Paul S; Jiang, Naibo; Patnaik, Anil K; Katta, Vish; Roy, Sukesh; Gord, James R

2018-04-01

Two-color, planar laser-induced fluorescence (PLIF)-based two-dimensional (2D) thermometry techniques for reacting flows, which are typically developed in the laboratory conditions, face a stiff challenge in their practical implementation in harsh environments such as combustion rigs. In addition to limited optical access, the critical experimental conditions (i.e., uncontrolled humidity, vibration, and large thermal gradients) often restrict sensitive laser system operation and cause difficulties maintaining beam-overlap. Thus, an all fiber-coupled, two-color OH-PLIF system has been developed, employing two long optical fibers allowing isolation of the laser and signal-collection systems. Two OH-excitation laser beams (∼283 nm and ∼286 nm) are delivered through a common 6 m long, 400 µm core, deep ultraviolet (UV)-enhanced multimode fiber. The fluorescence signal (∼310 nm) is collected by a 3 m long, UV-grade imaging fiber. Proof-of-principle temperature measurements are demonstrated in atmospheric pressure, near adiabatic, CH 4 /O 2 /N 2 jet flames. The effects of the excitation pulse interval on fiber transmission are investigated. The proof-of-principle measurements show significant promise for thermometry in harsh environments such as gas turbine engine tests.

New Aspects of the Structure of Human Scalp Hair-II: Tubular Structure and Material Flow Property of the Medulla.

PubMed

Yamauchi, Asao; Yamauchi, Kiyoshi

Asian scalp hair fibers were made thin by treatment with papain or sliced along the longitudinal axis or randomly cut by mechanical means. Optical microscopic observations of the resulting specimens indicated that (i) the medulla (M) consisted of two types of the M-surrounding cells which were linearly linked one another to form a tubular structure running through the fiber and (ii) the drum-shaped vesicles containing small proteinous granules were neatly or sparsely stored within the tube. On the other hand, H + and OH - ions were able to move spontaneously from one end to another through the M tube. Large molecules such as an anthocyanin dye (from purple sweet potato) were also capable of flowing through the M tube, especially rapidly when DC voltage was applied between the two ends of the hair fiber. The possible function of the M is briefly discussed in conjunction with the tubular structure and the material flow property.

Initial Performance Evaluation of Optical Fibers and Sensors Under High-Energy Electron Beam Irradiation

NASA Astrophysics Data System (ADS)

Palmer, Matthew E.; Slusher, David; Fielder, Robert S.

2006-01-01

In this paper, recent work on the performance of optical fiber, fiber optic sensors, and fiber optic connectors under the influence of a high-energy electron beam is presented. Electron beam irradiation is relevant for the Jupiter Icy Moons Orbiter (JIMO) mission due to the high electron radiation environment surrounding Jupiter. As an initial feasibility test, selected optical fiber components were exposed to dose levels relevant to the Jupiter environment. Three separate fiber types were used: one series consisted of pure silica core fiber, two other series consisted of different levels of Germania-doped fiber. Additionally, a series of fused silica Extrinsic Fabry-Perot Interferometer (EFPI)-based fiber optic sensors and two different types of fiber optic connectors were tested. Two types of fiber coatings were evaluated: acrylate and polyimide. All samples were exposed to three different dose levels: 2 MRad, 20 MRad, and 50 MRad. Optical loss measurements were made on the optical fiber spools as a function of wavelength between 750 and 1750nm at periodic intervals up to 75 hrs after exposure. Attenuation is minimal and wavelength-dependent. Fiber optic sensors were evaluated using a standard EFPI sensor readout and diagnostic system. Optical connectors and optical fiber coatings were visually inspected for degradation. Additionally, tensile testing and minimum bend radius testing was conducted on the fibers. Initial loss measurements indicate a low-level of induced optical attenuation in the fiber which recovers with time. The fiber optic sensors exhibited no observable degradation after exposure. The optical fiber connectors and coatings also showed no observable degradation. In addition to harsh environment survivability, fiber optic sensors offer a number of intrinsic advantages for space nuclear power applications including extremely low mass, immunity to electromagnetic interference, self diagnostics / prognostics, and smart sensor capability. Deploying fiber optic sensors on future space exploration missions would provide a substantial improvement in spacecraft instrumentation.

Fiber distributed feedback laser

NASA Technical Reports Server (NTRS)

Elachi, C.; Evans, G. A.; Yeh, C. (Inventor)

1976-01-01

Utilizing round optical fibers as communication channels in optical communication networks presents the problem of obtaining a high efficiency coupling between the optical fiber and the laser. A laser is made an integral part of the optical fiber channel by either diffusing active material into the optical fiber or surrounding the optical fiber with the active material. Oscillation within the active medium to produce lasing action is established by grating the optical fiber so that distributed feedback occurs.

An Optical Fiber Viscometer Based on Long-Period Fiber Grating Technology and Capillary Tube Mechanism

PubMed Central

Wang, Jian-Neng; Tang, Jaw-Luen

2010-01-01

This work addresses the development and assessment of a fiber optical viscometer using a simple and low-cost long-period fiber grating (LPFG) level sensor and a capillary tube mechanism. Previous studies of optical viscosity sensors were conducted by using different optical sensing methods. The proposed optical viscometer consists of an LPFG sensor, a temperature-controlled chamber, and a cone-shaped reservoir where gravitational force could cause fluid to flow through the capillary tube. We focused on the use of LPFGs as level sensors and the wavelength shifts were not used to quantify the viscosity values of asphalt binders. When the LPFG sensor was immersed in the constant volume (100 mL) AC-20 asphalt binder, a wavelength shift was observed and acquired using LabVIEW software and GPIB controller. The time spent between empty and 100 mL was calculated to determine the discharge time. We simultaneously measured the LPFG-induced discharge time and the transmission spectra both in hot air and AC-20 asphalt binder at five different temperatures, 60, 80, 100, 135, and 170 Celsius. An electromechanical rotational viscometer was also used to measure the viscosities, 0.15–213.80 Pa·s, of the same asphalt binder at the above five temperatures. A non-linear regression analysis was performed to convert LPFG-induced discharge time into viscosities. Comparative analysis shows that the LPFG-induced discharge time agreed well with the viscosities obtained from the rotational viscometer. PMID:22163519

A Compact Tunable Diode Laser Absorption Spectrometer to Monitor CO2 at 2.7 μm Wavelength in Hypersonic Flows

PubMed Central

Vallon, Raphäel; Soutadé, Jacques; Vérant, Jean-Luc; Meyers, Jason; Paris, Sébastien; Mohamed, Ajmal

2010-01-01

Since the beginning of the Mars planet exploration, the characterization of carbon dioxide hypersonic flows to simulate a spaceship’s Mars atmosphere entry conditions has been an important issue. We have developed a Tunable Diode Laser Absorption Spectrometer with a new room-temperature operating antimony-based distributed feedback laser (DFB) diode laser to characterize the velocity, the temperature and the density of such flows. This instrument has been tested during two measurement campaigns in a free piston tunnel cold hypersonic facility and in a high enthalpy arc jet wind tunnel. These tests also demonstrate the feasibility of mid-infrared fiber optics coupling of the spectrometer to a wind tunnel for integrated or local flow characterization with an optical probe placed in the flow. PMID:22219703

Mesh-type acoustic vector sensor

NASA Astrophysics Data System (ADS)

Zalalutdinov, M. K.; Photiadis, D. M.; Szymczak, W. G.; McMahon, J. W.; Bucaro, J. A.; Houston, B. H.

2017-07-01

Motivated by the predictions of a theoretical model developed to describe the acoustic flow force exerted on closely spaced nano-fibers in a viscous medium, we have demonstrated a novel concept for a particle velocity-based directional acoustic sensor. The central element of the concept exploits the acoustically induced normal displacement of a fine mesh as a measure of the collinear projection of the particle velocity in the sound wave. The key observations are (i) the acoustically induced flow force on an individual fiber within the mesh is nearly independent of the fiber diameter and (ii) the mesh-flow interaction can be well-described theoretically by a nearest neighbor coupling approximation. Scaling arguments based on these two observations indicate that the refinement of the mesh down to the nanoscale leads to significant improvements in performance. The combination of the two dimensional nature of the mesh together with the nanoscale dimensions provides a dramatic gain in the total length of fiber exposed to the flow, leading to a sensitivity enhancement by orders of magnitude. We describe the fabrication of a prototype mesh sensor equipped with optical readout. Preliminary measurements carried out over a considerable bandwidth together with the results of numerical simulations are in good agreement with the theory, thus providing a proof of concept.

Fiber optic monitoring device

DOEpatents

Samborsky, James K.

1993-01-01

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

Fiber optic connector

DOEpatents

Rajic, S.; Muhs, J.D.

1996-10-22

A fiber optic connector and method for connecting composite materials within which optical fibers are imbedded are disclosed. The fiber optic connector includes a capillary tube for receiving optical fibers at opposing ends. The method involves inserting a first optical fiber into the capillary tube and imbedding the unit in the end of a softened composite material. The capillary tube is injected with a coupling medium which subsequently solidifies. The composite material is machined to a desired configuration. An external optical fiber is then inserted into the capillary tube after fluidizing the coupling medium, whereby the optical fibers are coupled. 3 figs.

Utility of an optically-based, micromechanical system for printing collagen fibers

PubMed Central

Paten, Jeffrey A.; Tilburey, Graham E.; Molloy, Eileen A.; Zareian, Ramin; Trainor, Christopher V.

2013-01-01

Collagen's success as the principal structural element in load-bearing, connective tissue has motivated the development of numerous engineering approaches designed to recapitulate native fibril morphology and strength. It has been shown recently that collagen fibers can be drawn from monomeric solution through a fiber forming buffer (FFB), followed by numerous additional treatments in a complex serial process. However, internal fibril alignment, packing and resultant mechanical behavior of the fibers have not been optimized and remain inferior to native tissue. Further, no system has been developed which permits simultaneous application of molecular crowding, measurement of applied load, and direct observation of polymerization dynamics during fiber printing. The ability to perform well-controlled investigations early in the process of fiber formation, which vary single input parameters (i.e. collagen concentration, crowding agent concentration, draw rate, flow rate, temperature, pH, etc.) should substantially improve fiber morphology and strength. We have thus designed, built, and tested a versatile, in situ, optically-based, micromechanical assay and fiber printing system which permits the correlation of parameter changes with mechanical properties of fibers immediately after deposition into an FFB. We demonstrate the sensitivity of the assay by detecting changes in the fiber mechanics in response to draw rate, collagen type, small changes in the molecular crowding agent concentration and to variations in pH. In addition we found the ability to observe fiber polymerization dynamics leads to intriguing new insights into collagen assembly behavior. PMID:23352045

[System continuity and energy distribution in laser-induced thermo therapy (LITT)].

PubMed

Pech, M; Werk, M; Beck, A; Stohlmann, A; Ricke, J

2002-06-01

Evaluation of the continuity and energy distribution of a laser system for laser-induced thermo therapy. For evaluation of the continuity of laser optical devices, laser generating units and optical fibers of three different manufactures (Dornier, Hüttinger, Somatex), we used the equipment to generate a laser beam of 25 Watt for 60 minutes. Measurements of the applied energy were done sequentially with two MY Test (Fa. Hüttinger) units. We also performed two in vitro ablations of animal liver tissue with different fiber optics [Mikrodom A 13-0540, Microflexx REF A 13-0561 (Hüttinger), Diffusor-Tip H-6111-T 3, Diffusor H-6111-T 4 (Dornier), Somaflex-Diffusor (Somatex)] over 20 minutes at- an energy flow of 25 J per second. We then evaluated the geometry of coagulation. The different equipment used for our tests showed differences of a maximum of 10 %. Some components did not work properly in certain configurations even though the manufacturer assured it would. We saw significant differences in the ablation characteristics of the different fiber optics, especially in axial and frontal directions. Knowledge of the different characteristics in energy distribution and ablation characteristics are an important factor in performing a successful laser-induced thermo therapy.

[Studies on a sequential injection renewable surface reflectance spectrophotometric system using a microchip flow cell].

PubMed

Wang, Jian-ya; Fang, Zhao-lun

2002-02-01

A microchip flow cell was developed for flow injection renewable surface assay by reflectance spectrophotometry. The flow cell was coupled to a sequential injection system and optical fiber photometric detection system. The flow cell featured a three-layer structure. The flow channel was cut into a silicone rubber membrance which formed the middle layer, and a porous filter was inlayed across a widened section of the channel to trap microbeads introduced into the flow cell. The area of the detection window of the flow cell was approximately 3.6 mm2, the volume of the bead trapped in the flow cell was 2.2 microL, the depth of the bead layer was 600 microns. A multistrand bifurcated optical fiber was coupled with incident light, detector and flow cell. The chromogenic reaction of Cr(VI) with 1,5-diphenylcarbohydrazide (DPC) which was adsorbed on trapped Polysorb C-18 beads was used as a model reaction to optimize the flow cell design and the experimental system. The reflectance of the renewable reaction surface was monitored at 540 nm. With 100 microL sample loaded and 1.0 mL.min-1 carrier flow rate, the linear response range was 0-0.6 microgram.mL-1 Cr(VI). A detection limit (3 sigma) of 6 ng.mL-1, precision of 1.5% RSD(n = 11), and a throughput of 64 samples per hour were achieved. Considerations in system and flow cell design, the influence of depth of the bead layer, weight of beads used, and the flow rates of carrier stream on the performance were discussed.

Time-Resolved Optical Measurements of Fuel-Air Mixedness in Windowless High Speed Research Combustors

NASA Technical Reports Server (NTRS)

Nguyen, Quang-Viet

1998-01-01

Fuel distribution measurements in gas turbine combustors are needed from both pollution and fuel-efficiency standpoints. In addition to providing valuable data for performance testing and engine development, measurements of fuel distributions uniquely complement predictive numerical simulations. Although equally important as spatial distribution, the temporal distribution of the fuel is an often overlooked aspect of combustor design and development. This is due partly to the difficulties in applying time-resolved diagnostic techniques to the high-pressure, high-temperature environments inside gas turbine engines. Time-resolved measurements of the fuel-to-air ratio (F/A) can give researchers critical insights into combustor dynamics and acoustics. Beginning in early 1998, a windowless technique that uses fiber-optic, line-of-sight, infrared laser light absorption to measure the time-resolved fluctuations of the F/A (refs. 1 and 2) will be used within the premixer section of a lean-premixed, prevaporized (LPP) combustor in NASA Lewis Research Center's CE-5 facility. The fiber-optic F/A sensor will permit optical access while eliminating the need for film-cooled windows, which perturb the flow. More importantly, the real-time data from the fiber-optic F/A sensor will provide unique information for the active feedback control of combustor dynamics. This will be a prototype for an airborne sensor control system.

Dynamical tests on fiber optic data taken from the riser section of a circulating fluidized bed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, E.M.; Guenther, C.P.; Breault, R.W.

2007-11-01

Dynamical tests have been applied to fiber optic data taken from a cold-flow circulating fluidized bed to characterize flow conditions, identify three time and/or length scales (macro, meso, and micro), and understand the contribution these scales have on the raw data. The characteristic variable analyzed is the raw voltage signal obtained from a fiber-optic probe taken at various axial and radial positions under different loading conditions so that different flow regimes could be attained. These experiments were carried out with the bed material of 812 μm cork particles. The characterization was accomplished through analysis of the distribution of the signalmore » through the third and fourth moments of skewness and excess kurtosis. A generalization of the autocorrelation function known as the average mutual information function was analyzed by examining the function’s first minimum, identifying the point at which successive elements are no longer correlated. Further characterization was accomplished through the correlation dimension, a measure of the complexity of the attractor. Lastly, the amount of disorder of the system is described by a Kolmogorov-type entropy estimate. All six aforementioned tests were also implemented on ten levels of detail coefficients resulting from a discrete wavelet transformation of the same signal as used above. Through this analysis it is possible to identify and describe micro (particle level), meso (clustering or turbulence level), and macro (physical or dimensional level) length scales even though some literature considers these scales inseparable [6]. This investigation also used detail wavelet coefficients in conjunction with ANOVA analysis to show which scales have the most impact on the raw signal resulting from local hydrodynamic conditions.« less

Theoretical and experimental analysis of analyte transport in a fiber-optic, protein C immuno-biosensor.

PubMed

Tang, Liang; Kwon, Hyun J; Kang, Kyung A

2004-12-30

Protein C (PC) is an important anticoagulant in human blood plasma, and early diagnosis of PC deficiency is critical for preventing dangerous thromboembolic complications. A fiber-optic PC immuno-biosensor has been under development in our research group for real-time PC-deficiency diagnosis. The sensor has demonstrated a good sensitivity and specificity for quantifying PC in buffered solutions. However, for plasma samples, with a limited sample reaction time, the sensor produced only 30% of the signal intensity of PC in buffer. The high plasma viscosity (1.9 cP) was speculated as the major reason for signal intensity reduction. In this investigation, the sensing performance of the fiber-optic PC biosensor is systematically characterized in terms of physical and chemical properties of the sample media. Theoretical and experimental analyses indicate that the reduced diffusion rate of PC molecules in viscous samples caused the sensing system to be more mass-transfer-limited. Convective flow of sample/reagent solutions during immunoreactions can increase the rate of the analyte mass transport from the bulk solution to the sensor surface, with reaction kinetics changing from mass-transfer-limited to reaction-limited as flow velocity increases. It was shown that PC sensor performance was significantly improved for plasma samples with convection. The effect of the flow velocity and incubation times for samples and reagents on the sensor performance was also systematically analyzed to optimize the assay protocol for PC sensing. Currently, a 6-cm-long immuno-biosensor is capable of quantifying PC in plasma (1 mL) in the heterozygous PC deficiency range (0.5 to 2.5 microg/mL) within 5 minutes, at an average signal-to-noise ratio of 50. 2004 Wiley Periodicals, Inc.

Fiber optic and laser sensors IV; Proceedings of the Meeting, Cambridge, MA, Sept. 22-24, 1986

NASA Technical Reports Server (NTRS)

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

1987-01-01

The conference presents papers on industrial uses of fiber optic sensors, point and distributed polarimetric optical fiber sensors, fiber optic electric field sensor technology, micromachined resonant structures, single-mode fibers for sensing applications, and measurement techniques for magnetic field gradient detection. Consideration is also given to electric field meter and temperature measurement techniques for the power industry, the calibration of high-temperature fiber-optic microbend pressure transducers, and interferometric sensors for dc measurands. Other topics include the recognition of colors and collision avoidance in robotics using optical fiber sensors, the loss compensation of intensity-modulating fiber-optic sensors, and an embedded optical fiber strain tensor for composite structure applications.

Characterization of light transmissions in various optical fibers with proton beam

NASA Astrophysics Data System (ADS)

Song, Young Beom; Kim, Hye Jin; Kim, Mingeon; Lee, Bongsoo; Shin, Sang Hun; Yoo, Wook Jae; Jang, Kyoung Won; Hwang, Sung Won

2017-12-01

As a feasibility study on the development of a fiber-optic radiation sensor for proton therapy dosimetry, we characterized light transmissions of various commercial optical fibers such as silica and plastic based optical fibers by the irradiation of proton beams. In this study, we measured light transmission spectra of optical fibers as a function of absorbed doses of proton beams using a deuterium & tungsten halogen lamps and a spectrometer. To be used as a fiber-optic radiation sensor, the optical fibers should have the radiation resistant characteristics and provide stable output signals during the proton beam irradiation. In this study, we could select suitable optical fibers to be used in the fiber-optic radiation sensor without quenching effects for proton therapy dosimetry. As a result, the light transmittance of the optical fibers had decreasing trends with increasing absorbed dose as expected.

Microstructure of the smart composite structures with embedded fiber optic sensing nerves

NASA Astrophysics Data System (ADS)

Liu, Jingyuan; Luo, Fei; Li, Changchun; Ma, Naibin

1997-11-01

The composite structures with embedded optical fiber sensors construct a smart composite structure system, which may have the characteristics of the in-service self-measurement, self- recognition and self-judgement action. In the present work, we studied the microstructures of carbon/epoxy composite laminates with embedded sensing optical fibers, and the integration of optical fiber with composites was also discussed. The preliminary experiment results show that because of the difference between the sensing optical fibers and the reinforcing fibers in their size, the microstructure of the composites with embedded optical fibers will produce partial local changes in the area of embedded optical fiber, these changes may affect the mechanical properties of composite structures. When the optical fibers are embedded parallel to the reinforcing fibers, due to the composite prepregs are formed under a press action during its curing process, the reinforcing fibers can be arranged equably around the optical fibers. But when the optical fibers are embedded perpendicularly to the reinforcement fibers, the resin rich pocket will appear in the composite laminates surrounding the embedded optical fiber. The gas holes will be easily produced in these zones which may produce a premature failure of the composite structure. The photoelastic experiments are also given in the paper.

Microcautery based on zinc metallic nanoparticles photodeposited on the core of an optical fiber

NASA Astrophysics Data System (ADS)

Zaca-Morán, P.; Pastelín, C. F.; Morán, C.; Pérez-Sánchez, G. F.; Chávez, F.

2017-01-01

The experimental arrangement of a microcautery implemented by an optical fiber with zinc nanoparticles (ZnNPs) photodeposited on its core for the cauterization and coagulation in blood vessels hemostasis processes is presented. The interaction between a laser radiation source and the ZnNPS on the fiber core produces a controllable punctual heat source through the radiation intensity, which is capable of reaching a temperature up to 200 °C covering an area of approximately ten micrometers. By using three-to-four-month-old rats of CIIZ-V strain, we made several microcauterization experimental tests to stop blood flow. The findings show that the microcautery obliterates the smooth muscle of the blood vessels concatenating mutually to tissue in an average time of three seconds, at the same time, the blood elements responsible for the coagulation are thermally activated and thus the bleeding is stopped.

Tunable optical assembly with vibration dampening

NASA Technical Reports Server (NTRS)

Allison, Sidney G. (Inventor); Shams, Qamar A. (Inventor); Fox, Robert L. (Inventor); Fox, legal representative, Christopher L. (Inventor); Fox Chattin, legal representative, Melanie L. (Inventor)

2009-01-01

An optical assembly is formed by one or more piezoelectric fiber composite actuators having one or more optical fibers coupled thereto. The optical fiber(s) experiences strain when actuation voltage is applied to the actuator(s). Light passing through the optical fiber(s) is wavelength tuned by adjusting the actuation voltage.

SDN-controlled topology-reconfigurable optical mobile fronthaul architecture for bidirectional CoMP and low latency inter-cell D2D in the 5G mobile era.

PubMed

Cvijetic, Neda; Tanaka, Akihiro; Kanonakis, Konstantinos; Wang, Ting

2014-08-25

We demonstrate the first SDN-controlled optical topology-reconfigurable mobile fronthaul (MFH) architecture for bidirectional coordinated multipoint (CoMP) and low latency inter-cell device-to-device (D2D) connectivity in the 5G mobile networking era. SDN-based OpenFlow control is used to dynamically instantiate the CoMP and inter-cell D2D features as match/action combinations in control plane flow tables of software-defined optical and electrical switching elements. Dynamic re-configurability is thereby introduced into the optical MFH topology, while maintaining back-compatibility with legacy fiber deployments. 10 Gb/s peak rates with <7 μs back-to-back transmission latency and 29.6 dB total power budget are experimentally demonstrated, confirming the attractiveness of the new approach for optical MFH of future 5G mobile systems.

Rapid constructions of microstructures for optical fiber sensors using a commercial CO2 laser system.

PubMed

Irawan, Rudi; Chuan, Tjin Swee; Meng, Tay Chia; Ming, Tan Khay

2008-06-27

Exposing an optical fiber core to the measurand surrounding the fiber is often used to enhance the sensitivity of an optical fiber sensor. This paper reports on the rapid fabrication of microstructures in an optical fiber using a CO₂ laser system which help exposing the optical fiber core to the measurand. The direct-write CO₂ laser system used is originally designed for engraving the polymeric material. Fabrications of microstructures such as in-fiber microhole, D-shaped fiber, in-fiber microchannel, side-sliced fiber and tapered fiber were attempted. The microstructures in the fibers were examined using a SEM and an optical microscope. Quality of microstructures shown by the SEM images and promising results from fluorescence sensor tests using in-fiber microchannels of 100μm width, 210μm depth and 10mm length show the prospect of this method for use in optical fiber sensor development. The direct-write CO₂ laser system is a flexible and fast machining tool for fabricating microstructures in an optical fiber, and can possibly be a replacement of the time consuming chemical etching and polishing methods used for microstructure fabrications of optical the fiber sensors reported in other literatures.

Rapid Constructions of Microstructures for Optical Fiber Sensors Using a Commercial CO2 Laser System

PubMed Central

Irawan, Rudi; Chuan, Tjin Swee; Meng, Tay Chia; Ming, Tan Khay

2008-01-01

Exposing an optical fiber core to the measurand surrounding the fiber is often used to enhance the sensitivity of an optical fiber sensor. This paper reports on the rapid fabrication of microstructures in an optical fiber using a CO2 laser system which help exposing the optical fiber core to the measurand. The direct-write CO2 laser system used is originally designed for engraving the polymeric material. Fabrications of microstructures such as in-fiber microhole, D-shaped fiber, in-fiber microchannel, side-sliced fiber and tapered fiber were attempted. The microstructures in the fibers were examined using a SEM and an optical microscope. Quality of microstructures shown by the SEM images and promising results from fluorescence sensor tests using in-fiber microchannels of 100μm width, 210μm depth and 10mm length show the prospect of this method for use in optical fiber sensor development. The direct-write CO2 laser system is a flexible and fast machining tool for fabricating microstructures in an optical fiber, and can possibly be a replacement of the time consuming chemical etching and polishing methods used for microstructure fabrications of optical the fiber sensors reported in other literatures. PMID:19662114

Fiber optic temperature sensor

NASA Technical Reports Server (NTRS)

Sawatari, Takeo (Inventor); Gaubis, Philip A. (Inventor)

2000-01-01

A fiber optic temperature sensor uses a light source which transmits light through an optical fiber to a sensor head at the opposite end of the optical fiber from the light source. The sensor head has a housing coupled to the end of the optical fiber. A metallic reflective surface is coupled to the housing adjacent the end of the optical fiber to form a gap having a predetermined length between the reflective surface and the optical fiber. A detection system is also coupled to the optical fiber which determines the temperature at the sensor head from an interference pattern of light which is reflected from the reflective surface.

Fiber optic temperature sensor

NASA Technical Reports Server (NTRS)

Sawatari, Takeo (Inventor); Gaubis, Philip A. (Inventor); Mattes, Brenton L. (Inventor); Charnetski, Clark J. (Inventor)

1999-01-01

A fiber optic temperature sensor uses a light source which transmits light through an optical fiber to a sensor head at the opposite end of the optical fiber from the light source. The sensor head has a housing coupled to the end of the optical fiber. A metallic reflective surface is coupled to the housing adjacent the end of the optical fiber to form a gap having a predetermined length between the reflective surface and the optical fiber. A detection system is also coupled to the optical fiber which determines the temperature at the sensor head from an interference pattern of light which is reflected from the reflective surface.

Magneto-Optic Field Coupling in Optical Fiber Bragg Gratings

NASA Technical Reports Server (NTRS)

Carman, Gregory P. (Inventor); Mohanchandra, Panduranga K. (Inventor); Emmons, Michael C. (Inventor); Richards, William Lance (Inventor)

2016-01-01

The invention is a magneto-optic coupled magnetic sensor that comprises a standard optical fiber Bragg grating system. The system includes an optical fiber with at least one Bragg grating therein. The optical fiber has at least an inner core and a cladding that surrounds the inner core. The optical fiber is part of an optical system that includes an interrogation device that provides a light wave through the optical fiber and a system to determine the change in the index of refraction of the optical fiber. The cladding of the optical fiber comprises at least a portion of which is made up of ferromagnetic particles so that the ferromagnetic particles are subject to the light wave provided by the interrogation system. When a magnetic field is present, the ferromagnetic particles change the optical properties of the sensor directly.

Design of an All-Optical Network Based on LCoS Technologies

NASA Astrophysics Data System (ADS)

Cheng, Yuh-Jiuh; Shiau, Yhi

2016-06-01

In this paper, an all-optical network composed of the ROADMs (reconfigurable optical add-drop multiplexer), L2/L3 optical packet switches, and the fiber optical cross-connection for fiber scheduling and measurement based on LCoS (liquid crystal on silicon) technologies is proposed. The L2/L3 optical packet switches are designed with optical output buffers. Only the header of optical packets is converted to electronic signals to control the wavelength of input ports and the packet payloads can be transparently destined to their output ports. An optical output buffer is designed to queue the packets when more than one incoming packet should reach to the same destination output port. For preserving service-packet sequencing and fairness of routing sequence, a priority scheme and a round-robin algorithm are adopted at the optical output buffer. The wavelength of input ports is designed for routing incoming packets using LCoS technologies. Finally, the proposed OFS (optical flow switch) with input buffers can quickly transfer the big data to the output ports and the main purpose of the OFS is to reduce the number of wavelength reflections. The all-optical content delivery network is comprised of the OFSs for a large amount of audio and video data transmissions in the future.

Retinotopic and temporal organization of the optic nerve and tracts in the adult goldfish.

PubMed

Bunt, S M

1982-04-10

In order to investigate the role of the different factors controlling the pathways and termination sites of growing axons, selected optic fibers were traced from the eye to the tectum in adult goldfish either by filling them with HRP, or by severing a group of fibers and tracing their degeneration in 2 micrometers plastic sections stained with toluidine blue. Some fish received more than one lesion and others received both lesions and HRP applications. Two major rearrangements of the optic fibers were identified, one at the exit from the eye, the other within the optic tracts. Near the eye the optic fibers appear to be guided by the conformation of the underlying tissue planes that they encounter. The most recently added fibers, from the peripheral retina, grow over the vitread surface of the older fibers toward the blood vessel in the center of the optic nerve head. Behind the eye the fibers follow this blood vessel until it leaves the side of the optic nerve, and the fibers from peripheral retina are left as a single group on the ventral edge of the optic nerve cross section. As a consequence of this pattern of fiber growth the fibers form an orderly temporal sequence in the optic nerve, with the oldest fibers from the central retina on one side of the nerve and the youngest from peripheral retina on the other. In addition, the fibers are ordered topographically at right angles to this central-to-peripheral axis, with fibers from ventral retina on each edge of the nerve, dorsal fibers in the center, and nasal and temporal fibers in between. This arrangement of the optic fibers continues with only a little loss of precision up to the optic tracts. A more radical fiber rearrangement, seemingly incompatible with the fibers simply following tissue planes occurs within the optic tracts. Each newly arriving set of fibers grows over the surface of the optic tracts so that the older fibers come to lie deepest in the tracts. This segregation of fibers of different ages ensures that the rearrangement is limited to each layer of fibers. The abrupt reorganization of the fibers occurs as the tracts split around the nucleus rotundus to form the brachia of the optic tracts. The fibers are then arranged with temporal fibers nearest the nucleus rotundus and nasal fibers on the opposite edges of the brachia. From this point the fibers grow out over the tectal surface to their termination sites with only minimal rearrangements. Therefore the optic fiber rearrangements show evidence of several different sorts of constraints acting on the fibers at separate points in the optic pathway, each contributing to the final orderly arrangement of the fibers on the optic tectum.

Glutamate Receptor Aptamers and ALS

DTIC Science & Technology

2008-01-01

XXGATC ACC Consensus sequence RNA library Cloning and sequencing SELEX DIAGRAM Fig. 1. (a) Flow chart of SELEX. The library we used for SELEX...recording electrode and placed ~100 µm away from the hole. The linear flow rate of the solution is 1-4 cm/s. An optical fiber through which laser light for...channel recording (26) GluR6Q 1.1 × 104 4.2 × 102 Laser-pulse photolysis (67) 1.0 × 104 4.4 × 102 Fitting (52) 1.0 × 104 Flow measurement (46

Method for optical and mechanically coupling optical fibers

DOEpatents

Toeppen, J.S.

1996-10-01

A method and apparatus are disclosed for splicing optical fibers. A fluorescing solder glass frit having a melting point lower than the melting point of first and second optical fibers is prepared. The solder glass frit is then attached to the end of the first optical fiber and/or the end of the second optical fiber. The ends of the optical fibers are aligned and placed in close proximity to each other. The solder glass frit is then heated to a temperature which is lower than the melting temperature of the first and second optical fibers, but which is high enough to melt the solder glass frit. A force is applied to the first and second optical fibers pushing the ends of the fibers towards each other. As the solder glass flit becomes molten, the layer of molten solder glass is compressed into a thin layer between the first and second optical fibers. The thin compressed layer of molten solder glass is allowed to cool such that the first and second optical fibers are bonded to each other by the hardened layer of solder glass. 6 figs.

Method for optical and mechanically coupling optical fibers

DOEpatents

Toeppen, John S.

1996-01-01

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

Multi-channel measurement for hetero-core optical fiber sensor by using CMOS camera

NASA Astrophysics Data System (ADS)

Koyama, Yuya; Nishiyama, Michiko; Watanabe, Kazuhiro

2015-07-01

Fiber optic smart structures have been developed over several decades by the recent fiber optic sensor technology. Optical intensity-based sensors, which use LD or LEDs, can be suitable for the monitor system to be simple and cost effective. In this paper, a novel fiber optic smart structure with human-like perception has been demonstrated by using intensity-based hetero-core optical fiber sensors system with the CMOS detector. The optical intensity from the hetero-core optical fiber bend sensor is obtained as luminance spots indicated by the optical power distributions. A number of optical intensity spots are simultaneously readout by taking a picture of luminance pattern. To recognize the state of fiber optic smart structure with the hetero-core optical fibers, the template matching process is employed with Sum of Absolute Differences (SAD). A fiber optic smart glove having five optic fiber nerves have been employed to monitor hand postures. Three kinds of hand postures have been recognized by means of the template matching process. A body posture monitoring has also been developed by placing the wearable hetero-core optical fiber bend sensors on the body segments. In order for the CMOS system to be a human brain-like, the luminescent spots in the obtained picture were arranged to make the pattern corresponding to the position of body segments. As a result, it was successfully demonstrated that the proposed fiber optic smart structure could recognize eight kinds of body postures. The developed system will give a capability of human brain-like processing to the existing fiber optic smart structures.

Novel approach for the refractive index gradient measurement in microliter volumes using fiber-optic technology

NASA Astrophysics Data System (ADS)

Synovec, Robert E.; Renn, Curtiss N.

1991-07-01

The refractive index gradient (RIG) of hydrodynamically controlled profiles can be universally, yet sensitively, measured by carefully probing the radial RIG passing through a z-configuration flow cell. Fiber optic technology is applied in order to provide a narrow, collimated probe beam (100 micrometers diameter) that is deflected by a RIG and measured by a position sensitive detector. The fiber optic construction allows one to probe very small volumes (1 (mu) L to 3 (mu) L) amenable to microbore liquid chromatography ((mu) LC). The combination of (mu) LC and RIG detection is very useful for the analysis of trace quantities (ng injected amounts) of chemical species that are generally difficult to measure, i.e., species that are not amenable to absorbance detection or related techniques. Furthermore, the RIG detector is compatible with conventional mobile phase gradient and thermal gradient (mu) LC, unlike traditional RI detectors. A description of the RIG detector coupled with (mu) LC for the analysis of complex polymer samples is reported. Also, exploration into using the RIG detector for supercritical fluid chromatography is addressed.

An integrated fiberoptic-microfluidic device for agglutination detection and blood typing.

PubMed

Ramasubramanian, Melur K; Alexander, Stewart P

2009-02-01

In this paper, an integrated fiberoptic-microfluidic device for the detection of agglutination for blood type cross-matching has been described. The device consists of a straight microfluidic channel through with a reacted RBC suspension is pumped with the help of a syringe pump. The flow intersects an optical path created by an emitter-received fiber optic pair integrated into the microfluidic device. A 650 nm laser diode is used as the light source and a silicon photodiode is used to detect the light intensity. The spacing between the tips of the two optic fibers can be adjusted. When fiber spacing is large and the concentration of the suspension is high, scattering phenomenon becomes the dominant mechanism for agglutination detection while at low concentrations and small spacing, optointerruption becomes the dominant mechanism. An agglutination strength factor (ASF) is calculated from the data. Studies with a variety of blood types indicate that the sensing method correctly identifies the agglutination reaction in all cases. A disposable integrated device can be designed for future implementation of the method for near-bedside pre-transfusion check.

Optical fiber stripper positioning apparatus

DOEpatents

Fyfe, Richard W.; Sanchez, Jr., Amadeo

1990-01-01

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

Fiber optic vibration sensor

DOEpatents

Dooley, Joseph B.; Muhs, Jeffrey D.; Tobin, Kenneth W.

1995-01-01

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

Fiber optic vibration sensor

DOEpatents

Dooley, J.B.; Muhs, J.D.; Tobin, K.W.

1995-01-10

A fiber optic vibration sensor utilizes two single mode optical fibers supported by a housing with one optical fiber fixedly secured to the housing and providing a reference signal and the other optical fiber having a free span length subject to vibrational displacement thereof with respect to the housing and the first optical fiber for providing a signal indicative of a measurement of any perturbation of the sensor. Damping or tailoring of the sensor to be responsive to selected levels of perturbation is provided by altering the diameter of optical fibers or by immersing at least a portion of the free span length of the vibration sensing optical fiber into a liquid of a selected viscosity. 2 figures.

Design of fiber optic probes for laser light scattering

NASA Technical Reports Server (NTRS)

Dhadwal, Harbans S.; Chu, Benjamin

1989-01-01

A quantitative analysis is presented of the role of optical fibers in laser light scattering. Design of a general fiber optic/microlens probe by means of ray tracing is described. Several different geometries employing an optical fiber of the type used in lightwave communications and a graded index microlens are considered. Experimental results using a nonimaging fiber optic detector probe show that due to geometrical limitations of single mode fibers, a probe using a multimode optical fiber has better performance, for both static and dynamic measurements of the scattered light intensity, compared with a probe using a single mode fiber. Fiber optic detector probes are shown to be more efficient at data collection when compared with conventional approaches to measurements of the scattered laser light. Integration of fiber optic detector probes into a fiber optic spectrometer offers considerable miniaturization of conventional light scattering spectrometers, which can be made arbitrarily small. In addition static and dynamic measurements of scattered light can be made within the scattering cell and consequently very close to the scattering center.

Fiber optic sensor and method for making

DOEpatents

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

2010-05-18

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

Optical-Fiber Fluorosensors With Polarized Light Sources

NASA Technical Reports Server (NTRS)

Egalon, Claudio O.; Rogowski, Robert S.

1995-01-01

Chemiluminescent and/or fluorescent molecules in optical-fiber fluorosensors oriented with light-emitting dipoles along transverse axis. Sensor of proposed type captures greater fraction of chemiluminescence or fluorescence and transmits it to photodetector. Transverse polarization increases sensitivity. Basic principles of optical-fiber fluorosensors described in "Making Optical-Fiber Chemical Sensors More Sensitive" (LAR-14525), "Improved Optical-Fiber Chemical Sensors" (LAR-14607), and "Improved Optical-Fiber Temperature Sensors" (LAR-14647).

Refractive index retrieving of polarization maintaining optical fibers

NASA Astrophysics Data System (ADS)

Ramadan, W. A.; Wahba, H. H.; Shams El-Din, M. A.; Abd El-Sadek, I. G.

2018-01-01

In this paper, the cross-section images, of two different types of polarization maintaining (PM) optical fibers, are employed to estimate the optical phase variation due to transverse optical rays passing through these optical fibers. An adaptive algorithm is proposed to recognize the different areas constituting the PM optical fibers cross-sections. These areas are scanned by a transverse beam to calculate the optical paths for given values of refractive indices. Consequently, the optical phases across the PM optical fibers could be recovered. PM optical fiber is immersed in a matching fluid and set in the object arm of Mach-Zehnder interferometer. The produced interferograms are analyzed to extract the optical phases caused by the PM optical fibers. The estimated optical phases could be optimized to be in good coincidence with experimentally extracted ones. This has been achieved through changing of the PM optical fibers refractive indices to retrieve the correct values. The correct refractive indices values are confirmed by getting the best fit between the estimated and the extracted optical phases. The presented approach is a promising one because it provides a quite direct and accurate information about refractive index, birefringence and beat length of PM optical fibers comparing with different techniques handle the same task.

Fiber-Optic Anemometer Based on Silicon Fabry-Perot Interferometer

DTIC Science & Technology

2015-11-05

finding vast applications in all kinds of industrial processes, such as process control, food quality surveillance, wind turbines , environment...stronger flow ( wind ), which induces a decrease in the optical path of the silicon FPI, which lead to blueshifts the output spectrum. A higher wind ...Experimental results demonstrate that a wavelength shift -0.574 nm was observed for a wind speed of 4 m/s. Better sensitivity is to be expected when

Fiber optic crossbar switch for automatically patching optical signals

NASA Technical Reports Server (NTRS)

Bell, C. H. (Inventor)

1983-01-01

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

Optical Diagnostics in Medicine

NASA Astrophysics Data System (ADS)

Iftimia, Nicusor

2003-03-01

Light has a unique potential for non-invasive tissue diagnosis. The relatively short wavelength of light allows imaging of tissue at the resolution of histopathology. While strong multiple scattering of light in tissue makes attainment of this resolution difficult for thick tissues, most pathology emanates from epithelial surfaces. Therefore, high-resolution diagnosis of many important diseases may be achieved by transmitting light to the surface of interest. The recent fiber-optic implementation of technologies that reject multiple scattering, such as confocal microscopy and optical low coherence interferometry, have brought us one step closer to realizing non-invasive imaging of architectural and cellular features of tissue. Optical coherence tomography (OCT) can produce high-resolution cross-sectional images of biological structures. Clinical OCT studies conducted in the gastrointestinal tract and cardiovascular system have shown that OCT is capable of providing images of the architectural (> 20 µm) microanatomy of a variety of epithelial tissues, including the layered structure of squamous epithelium and arterial vessels. Fine Needle Aspiration- Low Coherence Interferometry (FNA-LCI) is another optical diagnostics technique, which is a suitable solution to increase the effectiveness of the FNA procedures. LCI is capable of measuring depth resolved (axial, z) tissue structure, birefringence, flow (Doppler shift), and spectra at a resolution of several microns. Since LCI systems are fiber-optic based, LCI probes may easily fit within the bore of a fine gauge needle, allowing diagnostic information to be obtained directly from the FNA biopsy site. Fiber optic spectrally encoded confocal microscopy (SECM) is a new confocal microscopy method, which eliminates the need for rapid beam scanning within the optical probe. This advance enables confocal microscopy to be performed through small diameter probes and will allow assessment of internal human tissues in vivo at the cellular level. A detailed description of several fiber optics based systems for early diseases diagnosis, as well as preliminary clinic results, will be presented.

Optical fiber end-facet polymer suspended-mirror devices

NASA Astrophysics Data System (ADS)

Yao, Mian; Wu, Jushuai; Zhang, A. Ping; Tam, Hwa-Yaw; Wai, P. K. A.

2017-04-01

This paper presents a novel optical fiber device based on a polymer suspended mirror on the end facet of an optical fiber. With an own-developed optical 3D micro-printing technology, SU-8 suspended-mirror devices (SMDs) were successfully fabricated on the top of a standard single-mode optical fiber. Optical reflection spectra of the fabricated SU- 8 SMDs were measured and compared with theoretical analysis. The proposed technology paves a way towards 3D microengineering of the small end-facet of optical fibers to develop novel fiber-optic sensors.

Improved Optical Fiber Chemical Sensors

NASA Technical Reports Server (NTRS)

Egalon, Claudio O.; Rogowski, Robert S.

1994-01-01

Calculations, based on exact theory of optical fiber, have shown how to increase optical efficiency sensitivity of active-core, step-index-profile optical-fiber fluorosensor. Calculations result of efforts to improve efficiency of optical-fiber chemical sensor of previous concept described in "Making Optical-Fiber Chemical Sensors More Sensitive" (LAR-14525). Optical fiber chemical detector of enhanced sensitivity made in several configurations. Portion of fluorescence or chemiluminescence generated in core, and launched directly into bound electromagnetic modes that propagate along core to photodetector.

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

PubMed Central

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

2012-01-01

In-line fiber optic interferometers have attracted intensive attention for their potential sensing applications in refractive index, temperature, pressure and strain measurement, etc. Typical in-line fiber-optic interferometers are of two types: Fabry-Perot interferometers and core-cladding-mode interferometers. It's known that the in-line fiber optic interferometers based on single-mode fibers can exhibit compact structures, easy fabrication and low cost. In this paper, we review two kinds of typical in-line fiber optic interferometers formed in single-mode fibers fabricated with different post-processing techniques. Also, some recently reported specific technologies for fabricating such fiber optic interferometers are presented. PMID:23112608

Estimation of regional cerebral blood flow distribution in infants by multichannel near-infrared spectroscopy with indocyanine green

NASA Astrophysics Data System (ADS)

Kusaka, Takashi; Isobe, Kenichi; Nagano, Keiko; Okubo, Kensuke; Yasuda, Saneyuki; Kawada, Kou; Itoh, Susumu; Onishi, Shoju; Oda, Ichiro; Wada, Yukihisa; Konishi, Ikuo; Tsunazawa, Yoshio

2001-06-01

This is the report on the use of multichannel near-infrared spectroscopy (MNIRS) with indocyanine green (ICG) to determine regional cerebral blood flow (rCBF) distribution disturbance in infants. We measured rCBF in an infant with subdural hemorrhage after surgical removal of a subdural hematoma. A probe consisting of 12 optical fibers, 6 for transmission and 6 for detection, was set on the right and then left temporal regions of the head of the infant, and 16 measuring points were determined. Changes in ICG concentration were recorded using MNIRS (near infrared optical imaging system, OMM-2000, Shimadzu Corp., Japan).

Architectures of fiber optic network in telecommunications

NASA Astrophysics Data System (ADS)

Vasile, Irina B.; Vasile, Alexandru; Filip, Luminita E.

2005-08-01

The operators of telecommunications have targeted their efforts towards realizing applications using broad band fiber optics systems in the access network. Thus, a new concept related to the implementation of fiber optic transmission systems, named FITL (Fiber In The Loop) has appeared. The fiber optic transmission systems have been extensively used for realizing the transport and intercommunication of the public telecommunication network, as well as for assuring the access to the telecommunication systems of the great corporations. Still, the segment of the residential users and small corporations did not benefit on large scale of this technology implementation. For the purpose of defining fiber optic applications, more types of architectures were conceived, like: bus, ring, star, tree. In the case of tree-like networks passive splitters (that"s where the name of PON comes from - Passive Optical Network-), which reduce significantly the costs of the fiber optic access, by separating the costs of the optical electronic components. That's why the passive fiber optics architectures (PON represent a viable solution for realizing the access at the user's loop. The main types of fiber optics architectures included in this work are: FTTC (Fiber To The Curb); FTTB (Fiber To The Building); FTTH (Fiber To The Home).

Blood flow velocity measurement by endovascular Doppler optical coherence tomography

NASA Astrophysics Data System (ADS)

Sun, Cuiru; Nolte, Felix; Vuong, Barry; Cheng, Kyle H. Y.; Lee, Kenneth K. C.; Standish, Beau A.; Courtney, Brian; Marotta, Tom R.; Yang, Victor X. D.

2013-03-01

Blood flow velocity and volumetric flow measurements are important parameters for assessment of the severity of stenosis and the outcome of interventional therapy. However, feasibility of intravascular flow measurement using a rotational catheter based phase resolved Doppler optical coherence tomography (DOCT) is difficult. Motion artefacts induced by the rotating optical imaging catheter, and the radially dependent noise background of measured Doppler signals are the main challenges encountered. In this study, a custom-made data acquisition system and developed algorithms to remove non-uniform rotational distortion (NURD) induced phase shift artefact by tracking the phase shift observed on catheter sheath. The flow velocity is calculated from Doppler shift obtained by Kasai autocorrelation after motion artefact removal. Blood flow velocity profiles in porcine carotid arteries in vivo were obtained at 100 frames/s with 500 A-lines/frame and DOCT images were taken at 20 frames/s with 2500 A-lines/frame. Time-varying velocity profiles were obtained at an artery branch. Furthermore, the identification of a vein adjacent to the catheterized vessel based on the color Doppler signal was also observed. The absolute measurement of intravascular flow using a rotating fiber catheter can provide insights to different stages of interventional treatment of stenosis in carotid artery.

Eliminating crystals in non-oxide optical fiber preforms and optical fibers

NASA Technical Reports Server (NTRS)

LaPointe, Michael R. (Inventor); Tucker, Dennis S. (Inventor)

2010-01-01

A method is provided for eliminating crystals in non-oxide optical fiber preforms as well as optical fibers drawn therefrom. The optical-fiber-drawing axis of the preform is aligned with the force of gravity. A magnetic field is applied to the preform as it is heated to at least a melting temperature thereof. The magnetic field is applied in a direction that is parallel to the preform's optical-fiber-drawing axis. The preform is then cooled to a temperature that is less than a glass transition temperature of the preform while the preform is maintained in the magnetic field. When the processed preform is to have an optical fiber drawn therefrom, the preform's optical-fiber-drawing axis is again aligned with the force of gravity and a magnetic field is again applied along the axis as the optical fiber is drawn from the preform.

Fiber optic coupled optical sensor

DOEpatents

Fleming, Kevin J.

2001-01-01

A displacement sensor includes a first optical fiber for radiating light to a target, and a second optical fiber for receiving light from the target. The end of the first fiber is adjacent and not axially aligned with the second fiber end. A lens focuses light from the first fiber onto the target and light from the target onto the second fiber.

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

PubMed

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

2012-09-24

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

Cable delay compensator for microwave signal distribution over optical fibers

NASA Astrophysics Data System (ADS)

Primas, Lori E.

1990-12-01

The basic principles of microwave fiber-optic systems are outlined with emphasis on fiber-optic cable delay compensators (CDC). Degradation of frequency and phase stability is considered, and it is pointed out that the long-term stability of a fiber-optic link is degraded by group delay variations due to temperature fluctuations in the optical fiber and low-frequency noise characteristics of the laser. A CDC employing a voltage-controlled oscillator to correct for phase variations in the optical fiber is presented, and the static as well as dynamic closed-loop analyses of the fiber-optic CDC are discussed. A constructed narrow-band fiber-optic CDC is shown to reduce phase variations caused by temperature fluctuations by a factor of 400. A wide-band CDC utilizing a temperature-controlled coil of fiber to compensate for phase delay is also proposed.

Omnidirectional fiber optic tiltmeter

DOEpatents

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

1983-06-30

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

Enhanced radiation resistant fiber optics

DOEpatents

Lyons, Peter B.; Looney, Larry D.

1993-01-01

A process for producing an optical fiber having enhanced radiation resitance is provided, the process including maintaining an optical fiber within a hydrogen-containing atmosphere for sufficient time to yield a hydrogen-permeated optical fiber having an elevated internal hydrogen concentration, and irradiating the hydrogen-permeated optical fiber at a time while the optical fiber has an elevated internal hydrogen concentration with a source of ionizing radiation. The radiation source is typically a cobalt-60 source and the fiber is pre-irradiated with a dose level up to about 1000 kilorads of radiation.

Enhanced radiation resistant fiber optics

DOEpatents

Lyons, P.B.; Looney, L.D.

1993-11-30

A process for producing an optical fiber having enhanced radiation resistance is provided, the process including maintaining an optical fiber within a hydrogen-containing atmosphere for sufficient time to yield a hydrogen-permeated optical fiber having an elevated internal hydrogen concentration, and irradiating the hydrogen-permeated optical fiber at a time while the optical fiber has an elevated internal hydrogen concentration with a source of ionizing radiation. The radiation source is typically a cobalt-60 source and the fiber is pre-irradiated with a dose level up to about 1000 kilorads of radiation. 4 figures.

Universal spin-momentum locked optical forces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalhor, Farid; Thundat, Thomas; Jacob, Zubin, E-mail: zjacob@purdue.edu

2016-02-08

Evanescent electromagnetic waves possess spin-momentum locking, where the direction of propagation (momentum) is locked to the inherent polarization of the wave (transverse spin). We study the optical forces arising from this universal phenomenon and show that the fundamental origin of recently reported non-trivial optical chiral forces is spin-momentum locking. For evanescent waves, we show that the direction of energy flow, the direction of decay, and the direction of spin follow a right hand rule for three different cases of total internal reflection, surface plasmon polaritons, and HE{sub 11} mode of an optical fiber. Furthermore, we explain how the recently reportedmore » phenomena of lateral optical force on chiral and achiral particles are caused by the transverse spin of the evanescent field and the spin-momentum locking phenomenon. Finally, we propose an experiment to identify the unique lateral forces arising from the transverse spin in the optical fiber and point to fundamental differences of the spin density from the well-known orbital angular momentum of light. Our work presents a unified view on spin-momentum locking and how it affects optical forces on chiral and achiral particles.« less

Evaluation of insertion characteristics of less invasive Si optoneural probe with embedded optical fiber

NASA Astrophysics Data System (ADS)

Morikawa, Takumi; Harashima, Takuya; Kino, Hisashi; Fukushima, Takafumi; Tanaka, Tetsu

2017-04-01

A less invasive Si optoneural probe with an embedded optical fiber was proposed and successfully fabricated. The diameter of the optical fiber was completely controlled by hydrogen fluoride etching, and the thinned optical fiber can propagate light without any leakage. This optical fiber was embedded in a trench formed inside a probe shank, which causes less damage to tissues. In addition, it was confirmed that the optical fiber embedded in the probe shank successfully irradiated light to optically stimulate gene transfected neurons. The electrochemical impedance of the probe did not change despite the light irradiation. Furthermore, probe insertion characteristics were evaluated in detail and less invasive insertion was clearly indicated for the Si optoneural probe with the embedded optical fiber compared with conventional optical neural probes. This neural probe with the embedded optical fiber can be used as a simple and easy tool for optogenetics and brain science.

Tapered fiber nanoprobes: plasmonic nanopillars on tapered optical fiber tips for large EM enhancement.

PubMed

Savaliya, Priten; Dhawan, Anuj

2016-10-01

Employing finite difference time domain simulations, we demonstrate that electromagnetic field enhancement is substantially greater for tapered optical fibers with plasmonic nanostructures present on their tips as compared with non-tapered optical fibers having those plasmonic nanostructures, or with tapered optical fibers without the plasmonic nanostructures. We also carried out fabrication of plasmonic nanostructures on optical fiber tips.

Test and Evaluation of Fiber Optic Sensors for High-Radiation Space Nuclear Power Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klemer, Daniel; Fielder, Robert S.; Stinson-Bagby, Kelly L.

2004-07-01

Fiber optic sensors can be used to measure a number of parameters, including temperature, strain, pressure and flow, for instrumentation and control of space nuclear power systems. In the past, this technology has often been rejected for use in such a high-radiation environment based on early experiments that revealed a number of degradation phenomena, including radiation-induced fiber attenuation, or 'graying', and Fiber Bragg Grating (FBG) fading and wavelength shift. However, this paper reports the results of recent experimental testing that demonstrates readability of fiber optic sensors to extremely high levels of neutron and gamma radiation. Both distributed Fiber Bragg Gratingmore » (FBG) sensors and single-point Extrinsic Fabry Perot Interferometer (EFPI) sensors were continuously monitored over a 2-month period, during which they were exposed to combined neutron and gamma radiation in both in-core and ex-core positions within a nuclear reactor. Total exposure reached approximately 2 x 10{sup 19} cm{sup -2} fast neutron (E > 1 MeV) fluence and 8.7 x 10{sup 8} Gy gamma for in-core sensors. FBG sensors were interrogated using a standard Luna Innovations FBG measurement system, which is based on optical frequency-domain reflectometer (OFDR) technology. Approximately 74% of the 19 FBG sensors located at the core centerline in the in-core position exhibited sufficient signal-to-noise ratio (SNR) to remain readable even after receiving the maximum dose. EFPI sensors were spectrally interrogated using a broadband probe source operating in the 830 nm wavelength region. While these single-point sensors failed early in the test, important additional fiber spectral transmission data was collected, which indicates that interrogation of EFPI sensors in alternate wavelength regions may allow significant improvement in sensor longevity for operation in high-radiation environments. This work was funded through a Small Business Innovative Research (SBIR) contract with the Nasa Glenn Research Center. (authors)« less

Development of In-Fiber Reflective Bragg Gratings as Shear Stress Monitors in Aerodynamic Facilities

NASA Technical Reports Server (NTRS)

Parmar, Devendra S.; Sprinkle, Danny R.; Singh, Jag J.

1998-01-01

Bragg gratings centered at nominal wavelengths of 1290 nm and 1300 run were inscribed in a 9/125 microns germano-silicate optical fiber, using continuous wave frequency doubled Ar+ laser radiation at 244 nm. Such gratings have been used extensively as temperature and strain monitors in smart structures. They have, however, never been used for measuring aerodynamic shear stresses. As a test of their sensitivity as shear stress monitors, a Bragg fiber attached to a metal plate was subjected to laminar flows in a glass pipe. An easily measurable large flow-induced wavelength shift (Delta Lambda(sub B)) was observed in the Bragg reflected wavelength. Thereafter, the grating was calibrated by making one time, simultaneous measurements of Delta Lambda(sub B) and the coefficient of skin friction (C(sub f)) with a skin friction balance, as a function of flow rates in a subsonic wind tunnel. Onset of fan-induced transition in the tunnel flow provided a unique flow rate for correlating Delta Lambda(sub B) and (C(sub f) values needed for computing effective modulus of rigidity (N(sub eff)) of the fiber attached to the metal plate. This value Of N(sub eff) is expected to remain constant throughout the elastic stress range expected during the Bragg grating aerodynamic tests. It has been used for calculating the value of Cf at various tunnel speeds, on the basis of measured values of Bragg wavelength shifts at those speeds.

Optical fibers and their applications 2012

NASA Astrophysics Data System (ADS)

Romaniuk, Ryszard S.; Wójcik, Waldemar

2013-01-01

XIVth Conference on Optical Fibers and Their Applications, Nałęczów 2012, which has been organized since more than 35 years, has summarized the achievements of the local optical fiber technology community, for the last year and a half. The conference specializes in developments of optical fiber technology, glass and polymer, classical and microstructured, passive and active. The event gathered around 100 participants. There were shown 60 presentations from 20 research and application groups active in fiber photonics, originating from academia and industry. Topical tracks of the Conference were: photonic materials, planar waveguides, passive and active optical fibers, propagation theory in nonstandard optical fibers, and new constructions of optical fibers. A panel discussion concerned teaching in fiber photonics. The conference was accompanied by a school on Optical Fiber Technology. The paper summarizes the chosen main topical tracks of the conference on Optical Fibers and Their Applications, Nałęczów 2012. The papers from the conference presentations will be published in Proc.SPIE. The next conference from this series is scheduled for January 2014 in Białowieża.

Fabrication of a miniaturized capillary waveguide integrated fiber-optic sensor for fluoride determination.

PubMed

Xiong, Yan; Wang, Chengjie; Tao, Tao; Duan, Ming; Tan, Jun; Wu, Jiayi; Wang, Dong

2016-05-10

Fluoride concentration is a key aspect of water quality and essential for human health. Too much or too little fluoride intake from water supplies is harmful to public health. In this study, a capillary waveguide integrated fiber-optic sensor was fabricated for fluoride measurement in water samples. The sensor was modularly designed with three parts, i.e., a light source, capillary flow cell and detector. When light propagated from a light emitting diode (LED) to the capillary waveguide cell through an excitation fiber, it interacted with the sensing reagent, and its intensity changed with different fluoride concentrations. Then, the light propagated to the detector through a detection fiber for absorption determination of fluoride according to Beer's law. This miniaturized sensor showed advantages of fast analysis (9.2 s) and small reagent demand (200 μL) per sample, and it also had a low detection limit (8 ppb) and high selectivity for fluoride determination. The sensor was applied to fluoride determination in different water samples. The results obtained were compared with those obtained by conventional spectrophotometry and ion chromatography, showing agreement and validating the sensor's potential application.

Optical fiber sensors measurement system and special fibers improvement

NASA Astrophysics Data System (ADS)

Jelinek, Michal; Hrabina, Jan; Hola, Miroslava; Hucl, Vaclav; Cizek, Martin; Rerucha, Simon; Lazar, Josef; Mikel, Bretislav

2017-06-01

We present method for the improvement of the measurement accuracy in the optical frequency spectra measurements based on tunable optical filters. The optical filter was used during the design and realization of the measurement system for the inspection of the fiber Bragg gratings. The system incorporates a reference block for the compensation of environmental influences, an interferometric verification subsystem and a PC - based control software implemented in LabView. The preliminary experimental verification of the measurement principle and the measurement system functionality were carried out on a testing rig with a specially prepared concrete console in the UJV Řež. The presented system is the laboratory version of the special nuclear power plant containment shape deformation measurement system which was installed in the power plant Temelin during last year. On the base of this research we started with preparation other optical fiber sensors to nuclear power plants measurement. These sensors will be based on the microstructured and polarization maintaining optical fibers. We started with development of new methods and techniques of the splicing and shaping optical fibers. We are able to made optical tapers from ultra-short called adiabatic with length around 400 um up to long tapers with length up to 6 millimeters. We developed new techniques of splicing standard Single Mode (SM) and Multimode (MM) optical fibers and splicing of optical fibers with different diameters in the wavelength range from 532 to 1550 nm. Together with development these techniques we prepared other techniques to splicing and shaping special optical fibers like as Polarization-Maintaining (PM) or hollow core Photonic Crystal Fiber (PCF) and theirs cross splicing methods with focus to minimalize backreflection and attenuation. The splicing special optical fibers especially PCF fibers with standard telecommunication and other SM fibers can be done by our developed techniques. Adjustment of the splicing process has to be prepared for any new optical fibers and new fibers combinations. The splicing of the same types of fibers from different manufacturers can be adjusted by several tested changes in the splicing process. We are able to splice PCF with standard telecommunication fiber with attenuation up to 2 dB. The method is also presented. Development of these new techniques and methods of the optical fibers splicing are made with respect to using these fibers to another research and development in the field of optical fibers sensors, laser frequency stabilization and laser interferometry based on optical fibers. Especially for the field of laser frequency stabilization we developed and present new techniques to closing microstructured fibers with gases inside.

Fiber optic sensors

NASA Technical Reports Server (NTRS)

Hesse, J.; Sohler, W.

1984-01-01

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

Demonstration of an ultra-wideband optical fiber inline polarizer with metal nano-grid on the fiber tip.

PubMed

Lin, Yongbin; Guo, Junpeng; Lindquist, Robert G

2009-09-28

Dramatic increase in the bandwidth of optical fiber inline polarizer can be achieved by using metal nano-grid on the fiber tip. However, high extinction ratio of such fiber polarizer requires high spatial frequency metal nano girds with high aspect ratio on the small area of optical fiber tip. We report the development of a nano-fabrication process on the optical fiber tip, and the design and realization of the first ultra-wideband fiber inline polarization device with Au nano gird fabricated on a single mode optical fiber end face.

Investigation of cladding and coating stripping methods for specialty optical fibers

NASA Astrophysics Data System (ADS)

Lee, Jung-Ryul; Dhital, Dipesh; Yoon, Dong-Jin

2011-03-01

Fiber optic sensing technology is used extensively in several engineering fields, including smart structures, health and usage monitoring, non-destructive testing, minimum invasive sensing, safety monitoring, and other advanced measurement fields. A general optical fiber consists of a core, cladding, and coating layers. Many sensing principles require that the cladding or coating layer should be removed or modified. In addition, since different sensing systems are needed for different types of optical fibers, it is very important to find and sort out the suitable cladding or coating removal method for a particular fiber. This study focuses on finding the cladding and coating stripping methods for four recent specialty optical fibers, namely: hard polymer-clad fiber, graded-index plastic optical fiber, copper/carbon-coated optical fiber, and aluminum-coated optical fiber. Several methods, including novel laser stripping and conventional chemical and mechanical stripping, were tried to determine the most suitable and efficient technique. Microscopic investigation of the fiber surfaces was used to visually evaluate the mechanical reliability. Optical time domain reflectometric signals of the successful removal cases were investigated to further examine the optical reliability. Based on our results, we describe and summarize the successful and unsuccessful methods.

Optical and mechanical response of high temperature optical fiber sensors

NASA Technical Reports Server (NTRS)

Sirkis, Jim

1991-01-01

The National Aerospace Plane (NASP) will experience temperatures as high as 2500 F at critical locations in its structure. Optical fiber sensors were proposed as a means of monitoring the temperature in these critical regions by either bonding the optical fiber to, or embedding the optical fiber in, metal matrix composite (MMC) components. Unfortunately, the anticipated NASP temperature ranges exceed the glass transition region of the optical fiber glass. The attempt is made to define the operating temperature range of optical fiber sensors from both optical and mechanical perspectives. A full non-linear optical analysis was performed by modeling the optical response of an isolated sensor cyclically driven through the glass transition region.

Fiber Optic Temperature Sensor Insert for High Temperature Environments

NASA Technical Reports Server (NTRS)

Black, Richard James (Inventor); Costa, Joannes M. (Inventor); Moslehi, Behzad (Inventor); Zarnescu, Livia (Inventor)

2017-01-01

A thermal protection system (TPS) test plug has optical fibers with FBGs embedded in the optical fiber arranged in a helix, an axial fiber, and a combination of the two. Optionally, one of the optical fibers is a sapphire FBG for measurement of the highest temperatures in the TPS plug. The test plug may include an ablating surface and a non-ablating surface, with an engagement surface with threads formed, the threads having a groove for placement of the optical fiber. The test plug may also include an optical connector positioned at the non-ablating surface for protection of the optical fiber during insertion and removal.

Liquid-filled hollow core microstructured polymer optical fiber.

PubMed

Cox, F M; Argyros, A; Large, M C J

2006-05-01

Guidance in a liquid core is possible with microstructured optical fibers, opening up many possibilities for chemical and biochemical fiber-optic sensing. In this work we demonstrate how the bandgaps of a hollow core microstructured polymer optical fiber scale with the refractive index of liquid introduced into the holes of the microstructure. Such a fiber is then filled with an aqueous solution of (-)-fructose, and the resulting optical rotation measured. Hence, we show that hollow core microstructured polymer optical fibers can be used for sensing, whilst also fabricating a chiral optical fiber based on material chirality, which has many applications in its own right.

Optical-fiber-to-waveguide coupling using carbon-dioxide-laser-induced long-period fiber gratings.

PubMed

Bachim, Brent L; Ogunsola, Oluwafemi O; Gaylord, Thomas K

2005-08-15

Optical fibers are expected to play a role in chip-level and board-level optical interconnects because of limitations on the bandwidth and level of integration of electrical interconnects. Therefore, methods are needed to couple optical fibers directly to waveguides on chips and on boards. We demonstrate optical-fiber-to-waveguide coupling using carbon-dioxide laser-induced long-period fiber gratings (LPFGs). Such gratings can be written in standard fiber and offer wavelength multiplexing-demultiplexing performance. The coupler fabrication process and the characterization apparatus are presented. The operation and the wavelength response of a LPFG-based optical-fiber-to-waveguide directional coupler are demonstrated.

Fiber Coupled Laser Diodes with Even Illumination Pattern

NASA Technical Reports Server (NTRS)

Howard, Richard T. (Inventor)

2007-01-01

An optical fiber for evenly illuminating a target. The optical fiber is coupled to a laser emitting diode and receives laser light. The la ser light travels through the fiber optic and exits at an exit end. T he exit end has a diffractive optical pattern formed thereon via etch ing, molding or cutting, to reduce the Gaussian profile present in co nventional fiber optic cables The reduction of the Gaussian provides an even illumination from the fiber optic cable.

Two classes of capillary optical fibers: refractive and photonic

NASA Astrophysics Data System (ADS)

Romaniuk, Ryszard S.

2008-11-01

This paper is a digest tutorial on some properties of capillary optical fibers (COF). Two basic types of capillary optical fibers are clearly distinguished. The classification is based on propagation mechanism of optical wave. The refractive, singlemode COF guides a dark hollow beam of light (DHB) with zero intensity on fiber axis. The photonic, singlemode COF carries nearly a perfect axial Gaussian beam with maximum intensity on fiber axis. A subject of the paper are these two basic kinds of capillary optical fibers of pure refractive and pure photonic mechanism of guided wave transmission. In a real capillary the wave may be transmitted by a mixed mechanism, refractive and photonic, with strong interaction of photonic and refractive guided wave modes. Refractive capillary optical fibers are used widely for photonic instrumentation applications, while photonic capillary optical fibers are considered for trunk optical communications. Replacement of classical, single mode, dispersion shifted, 1550nm optimized optical fibers for communications with photonic capillaries would potentially cause a next serious revolution in optical communications. The predictions say that such a revolution may happen within this decade. This dream is however not fulfilled yet. The paper compares guided modes in both kinds of optical fiber capillaries: refractive and photonic. The differences are emphasized indicating prospective application areas of these fibers.

Research and Development on Ultra-Lightweight Low-Loss Optical Fiber Communication Cable.

DTIC Science & Technology

FIBER OPTICS TRANSMISSION LINES, LIGHTWEIGHT), GLASS , FIBERS , ORGANIC COATINGS, POLYURETHANE RESINS, SOLUTIONS(GENERAL), POWDERS, ELECTROSTATICS...EXTRUSION, RUGGEDIZED EQUIPMENT, BROADBAND, OPTICAL COMMUNICATIONS, TACTICAL COMMUNICATIONS, FIBER OPTICS, LOSSES.

Velocity fields and optical turbulence near the boundary in a strongly convective laboratory flow

NASA Astrophysics Data System (ADS)

Matt, Silvia; Hou, Weilin; Goode, Wesley; Hellman, Samuel

2016-05-01

Boundary layers around moving underwater vehicles or other platforms can be a limiting factor for optical communication. Turbulence in the boundary layer of a body moving through a stratified medium can lead to small variations in the index of refraction, which impede optical signals. As a first step towards investigating this boundary layer effect on underwater optics, we study the flow near the boundary in the Rayleigh-Bénard laboratory tank at the Naval Research Laboratory Stennis Space Center. The tank is set up to generate temperature-driven, i.e., convective turbulence, and allows control of the turbulence intensity. This controlled turbulence environment is complemented by computational fluid dynamics simulations to visualize and quantify multi-scale flow patterns. The boundary layer dynamics in the laboratory tank are quantified using a state-of-the-art Particle Image Velocimetry (PIV) system to examine the boundary layer velocities and turbulence parameters. The velocity fields and flow dynamics from the PIV are compared to the numerical model and show the model to accurately reproduce the velocity range and flow dynamics. The temperature variations and thus optical turbulence effects can then be inferred from the model temperature data. Optical turbulence is also visible in the raw data from the PIV system. The newly collected data are consistent with previously reported measurements from high-resolution Acoustic Doppler Velocimeter profilers (Nortek Vectrino), as well as fast thermistor probes and novel next-generation fiber-optics temperature sensors. This multi-level approach to studying optical turbulence near a boundary, combining in-situ measurements, optical techniques, and numerical simulations, can provide new insight and aid in mitigating turbulence impacts on underwater optical signal transmission.

Performance comparison of a fiber optic communication system based on optical OFDM and an optical OFDM-MIMO with Alamouti code by using numerical simulations

NASA Astrophysics Data System (ADS)

Serpa-Imbett, C. M.; Marín-Alfonso, J.; Gómez-Santamaría, C.; Betancur-Agudelo, L.; Amaya-Fernández, F.

2013-12-01

Space division multiplexing in multicore fibers is one of the most promise technologies in order to support transmissions of next-generation peta-to-exaflop-scale supercomputers and mega data centers, owing to advantages in terms of costs and space saving of the new optical fibers with multiple cores. Additionally, multicore fibers allow photonic signal processing in optical communication systems, taking advantage of the mode coupling phenomena. In this work, we numerically have simulated an optical MIMO-OFDM (multiple-input multiple-output orthogonal frequency division multiplexing) by using the coded Alamouti to be transmitted through a twin-core fiber with low coupling. Furthermore, an optical OFDM is transmitted through a core of a singlemode fiber, using pilot-aided channel estimation. We compare the transmission performance in the twin-core fiber and in the singlemode fiber taking into account numerical results of the bit-error rate, considering linear propagation, and Gaussian noise through an optical fiber link. We carry out an optical fiber transmission of OFDM frames using 8 PSK and 16 QAM, with bit rates values of 130 Gb/s and 170 Gb/s, respectively. We obtain a penalty around 4 dB for the 8 PSK transmissions, after 100 km of linear fiber optic propagation for both singlemode and twin core fiber. We obtain a penalty around 6 dB for the 16 QAM transmissions, with linear propagation after 100 km of optical fiber. The transmission in a two-core fiber by using Alamouti coded OFDM-MIMO exhibits a better performance, offering a good alternative in the mitigation of fiber impairments, allowing to expand Alamouti coded in multichannel systems spatially multiplexed in multicore fibers.

Use of 3000 Bragg Grating Strain Sensors Distributed on Four Eight-meter Optical Fibers During Static Load Tests of a Composite Structure

NASA Technical Reports Server (NTRS)

Childers, Brooks A.; Froggatt, Mark E.; Allison, Sidney G.; Moore, Thomas C., Sr.; Hare, David A.; Batten, Christopher F.; Jegley, Dawn C.

2001-01-01

This paper describes the use of a fiber optic system to measure strain at thousands of locations along optical fibers where weakly reflecting Bragg gratings have been photoetched. The optical fibers were applied to an advanced composite transport wing along with conventional foil strain gages. A comparison of the fiber optic and foil gage systems used for this test will be presented including: a brief description of both strain data systems; a discussion of the process used for installation of the optical fiber; comparative data from the composite wing test; the processes used for the location and display of the high density fiber optic data. Calibration data demonstrating the potential accuracy of the fiber optic system will also be presented. The opportunities for industrial and commercial applications will be discussed. The fiber optic technique is shown to be a valuable augmentation to foil strain gages providing insight to structural behavior previously requiring reliance on modeling.

Fiber optic sensors for gas turbine control

NASA Technical Reports Server (NTRS)

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

2005-01-01

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.

Fiber optic sensors for gas turbine control

NASA Technical Reports Server (NTRS)

Shu, Emily Yixie (Inventor); Brown, Dale Marius (Inventor); Petrucco, Louis Jacob (Inventor); Lovett, Jeffery Allan (Inventor); Daum, Wolfgang (Inventor); Dunki-Jacobs, Robert John (Inventor)

2003-01-01

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.

Fiber optic sensors for gas turbine control

NASA Technical Reports Server (NTRS)

Shu, Emily Yixie (Inventor); Brown, Dale Marius (Inventor); Petrucco, Louis Jacob (Inventor); Lovett, Jeffery Allan (Inventor); Daum, Wolfgang (Inventor); Dunki-Jacobs, Robert John (Inventor)

1999-01-01

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.

Alternative Controller for a Fiber-Optic Switch

NASA Technical Reports Server (NTRS)

Peters, Robert

2007-01-01

A simplified diagram of a relatively inexpensive controller for a DiCon VX (or equivalent) fiber-optic switch -- an electromechanically actuated switch for optically connecting one or two input optical fibers to any of a number of output optical fibers is shown. DiCon VX fiber-optic switches are used primarily in research and development in the telecommunication industry. This controller can control any such switch having up to 32 output channels.

Video flowmeter

DOEpatents

Lord, D.E.; Carter, G.W.; Petrini, R.R.

1983-08-02

A video flowmeter is described that is capable of specifying flow nature and pattern and, at the same time, the quantitative value of the rate of volumetric flow. An image of a determinable volumetric region within a fluid containing entrained particles is formed and positioned by a rod optic lens assembly on the raster area of a low-light level television camera. The particles are illuminated by light transmitted through a bundle of glass fibers surrounding the rod optic lens assembly. Only particle images having speeds on the raster area below the raster line scanning speed may be used to form a video picture which is displayed on a video screen. The flowmeter is calibrated so that the locus of positions of origin of the video picture gives a determination of the volumetric flow rate of the fluid. 4 figs.

The comparison of two methods to manufacture fused biconical tapered optical fiber coupler

NASA Astrophysics Data System (ADS)

Wang, Yue; Liu, Hairong

2009-08-01

Optical fiber coupler is a directional coupler which is crucial component for optical fiber communication systems. The fused biconical taper is the most important method in facture of optical fiber coupler, with many advantages of low excess loss, precise coupling ratio, good consistency and stability. In this paper we have introduced a new method to manufacture optical fiber coupler. And more over the new manufacture process has been compared with the traditional manufacture method. In the traditional crafts, two optical fibers are parallel placed, and then use the method of tie a knot of the two optical fibers. In the new process, a new program of fiber placement is introduced. Two optical fibers are parallel placed in the middle of the fixture, and then in order to make the bare part of the optical fiber close as much as possible, the new plan using high temperature resistant material bind the both end of the fiber which are not removing the cladding. After many contrast tests, we can see that adopt the improved method of fiber placement, during the process of fiber pulling, the variation of optical power in the directional arm and the coupler arm are more smooth and steady. But the excess loss (EL) generated in the process of pulling is a bit higher than the traditional method of tie a knot. The tests show that the new method of optical fiber placement is feasible in the actual projects for the manufacture of coupler with low coupling ratio, but for the control of the EL still need further studying.

Methods and apparatus for optical switching using electrically movable optical fibers

DOEpatents

Peterson, Kenneth A [Albuquerque, NM

2007-03-13

Methods and apparatuses for electrically controlled optical switches are presented. An electrically controlled optical switch includes a fixture formed using a laminated dielectric material, a first optical fiber having a fixed segment supported by the fixture and a movable segment extending into a cavity, a second optical fiber having a fixed segment supported by the fixture and an extended segment where an optical interconnect may be established between the first optical fiber and the second optical fiber, and a first electrical actuator functionally coupled to the fixture and the first fiber which alters a position of the moveable segment, based upon a control signal, for changing a state of the optical interconnect between one of two states.

Radial-firing optical fiber tip containing conical-shaped air-pocket for biomedical applications.

PubMed

Lee, Seung Ho; Ryu, Yong-Tak; Son, Dong Hoon; Jeong, Seongmook; Kim, Youngwoong; Ju, Seongmin; Kim, Bok Hyeon; Han, Won-Taek

2015-08-10

We report a novel radial-firing optical fiber tip containing a conical-shaped air-pocket fabricated by deforming a hollow optical fiber using electric arc-discharge process. The hollow optical fiber was fusion spliced with a conventional optical fiber, simultaneously deforming into the intagliated conical-shaped region along the longitudinal fiber-axis of the fiber due to the gradual collapse of the cavity of the hollow optical fiber. Then the distal-end of the hollow optical fiber was sealed by the additional arc-discharge in order to obstruct the inflow of an external bio-substance or liquid to the inner air surface during the surgical operations, resulting in the formation of encased air-pocket in the silica glass fiber. Due to the total internal reflection of the laser beam at the conical-shaped air surface, the laser beam (λ = 632.8 nm) was deflected to the circumferential direction up to 87 degree with respect to the fiber-axis.

[The design and application of domestic mid-IR fiber optics].

PubMed

Weng, Shi-fu; Gao, Jian-ping; Xu, Yi-zhuang; Yang, Li-min; Bian, Bei-ya; Xiang, Hai-bo; Wu, Jin-guang

2004-05-01

The combination of mid-IR fiber optics and FTIR has made the non-invasive determination of samples in situ, with long distances, and in vivo possible. In this paper domestic mid-IR fiber optics was improved to investigate the transmission ability of fiber optics and its application to the sample determination. New design was applied to obtaining one bare fiber optics, which has a minor energy loss and higher signal-to-noise ratio. The spectra of H2O/EtOH and tissue samples were measured using the new designed fiber optics and the results show that home-made mid-IR fiber optics can be applied to the field of determination of general and biological samples.

Demonstration of theoretical and experimental simulations in fiber optics course

NASA Astrophysics Data System (ADS)

Yao, Tianfu; Wang, Xiaolin; Shi, Jianhua; Lei, Bing; Liu, Wei; Wang, Wei; Hu, Haojun

2017-08-01

"Fiber optics" course plays a supporting effect in the curriculum frame of optics and photonics at both undergraduate and postgraduate levels. Moreover, the course can be treated as compulsory for students specialized in the fiber-related field, such as fiber communication, fiber sensing and fiber light source. The corresponding content in fiber optics requires the knowledge of geometrical and physical optics as background, including basic optical theory and fiber components in practice. Thus, to help the students comprehend the relatively abundant and complex content, it is necessary to investigate novel teaching method assistant the classic lectures. In this paper, we introduce the multidimensional pattern in fiber-optics teaching involving theoretical and laboratory simulations. First, the theoretical simulations is demonstrated based on the self-developed software named "FB tool" which can be installed in both smart phone with Android operating system and personal computer. FB tool covers the fundamental calculations relating to transverse modes, fiber lasers and nonlinearities and so on. By comparing the calculation results with other commercial software like COMSOL, SFTool shows high accuracy with high speed. Then the laboratory simulations are designed including fiber coupling, Erbium doped fiber amplifiers, fiber components and so on. The simulations not only supports students understand basic knowledge in the course, but also provides opportunities to develop creative projects in fiber optics.

Characterization of a Fiber Optic Coupled Dosimeter for Clinical Electron Beam Dosimetry

DTIC Science & Technology

2010-04-29

2010 2. REPORT TYPE 3. DATES COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE Characterization of a Fiber Optic Coupled Dosimeter for...Fiber Optic Coupled Dosimeter for Clinical Electron Beam Dosimetry. Abstract approved: Camille J. Lodwick Fiber-optic-coupled dosimeters ...Rights Reserved CHARACTERIZATION OF A FIBER OPTIC COUPLED DOSIMETER FOR CLINICAL ELECTRON

Fiber optic and laser sensors X; Proceedings of the Meeting, Boston, MA, Sept. 8-11, 1992

NASA Technical Reports Server (NTRS)

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

1993-01-01

Topics addressed include acoustic and pressure sensors; fiber optic gyros; electric and magnetic field sensors; bend, strain, and temperature sensors; industrial applications of sensors; and processing techniques. Particular attention is given to fiber optic interferometric acoustic sensors for wind tunnel applications, polished coupler and resonator fabrication, second-harmonic detection for rotation sensing in fiber optic gyros, simplified control theory in closed-loop fiber optic gyroscopes, and a Fabry-Perot sensor with digital signal processing for the measurement of magnetostriction. Also discussed are a Bragg fiber laser sensor, commercialization of fiber optic strain gauge systems, thermal ignition in hazardous environments due to stray light from optical fibers, a system for absolute measurements by interferometric sensors, and high-performance interferometric demodulation techniques.

Energetic radiation influence on temperature dependency of Brillouin frequency in optical fibers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pheron, X.; Ouerdane, Y.; Delepine-Lesoille, S.

We present a post mortem study of the influence of energetic radiation on optical fiber Brillouin sensors, both Brillouin spectrum and its temperature dependency in two different fibers, a photosensitive optical fiber and a SMF28. The target application is nuclear wastes repository monitoring where optical fiber Brillouin sensors might be exposed to energetic radiation. UV exposure induced optical losses, Brillouin frequency shifts up to 28 MHz and even a variation of the temperature dependency. The photosensitive optical fiber resulted more sensitive than SMF28{sup TM}. (authors)

Method for the continuous processing of hermetic fiber optic components and the resultant fiber optic-to-metal components

DOEpatents

Kramer, D.P.

1994-08-09

Hermetic fiber optic-to-metal components and method for making hermetic fiber optic-to-metal components by assembling and fixturing elements comprising a metal shell, a glass preform, and a metal-coated fiber optic into desired relative positions and then sealing said fixtured elements preferably using a continuous heating process is disclosed. The resultant hermetic fiber optic-to-metal components exhibit high hermeticity and durability despite the large differences in thermal coefficients of expansion among the various elements. 3 figs.

Monitoring techniques for the manufacture of tapered optical fibers.

PubMed

Mullaney, Kevin; Correia, Ricardo; Staines, Stephen E; James, Stephen W; Tatam, Ralph P

2015-10-01

The use of a range of optical techniques to monitor the process of fabricating optical fiber tapers is investigated. Thermal imaging was used to optimize the alignment of the optical system; the transmission spectrum of the fiber was monitored to confirm that the tapers had the required optical properties and the strain induced in the fiber during tapering was monitored using in-line optical fiber Bragg gratings. Tapers were fabricated with diameters down to 5 μm and with waist lengths of 20 mm using single-mode SMF-28 fiber.

Optical Energy Transfer and Conversion System

NASA Technical Reports Server (NTRS)

Hogan, Bartholomew P. (Inventor); Stone, William C. (Inventor)

2015-01-01

An optical power transfer system comprising a fiber spooler, a fiber optic rotary joint mechanically connected to the fiber spooler, and an electrical power extraction subsystem connected to the fiber optic rotary joint with an optical waveguide. Optical energy is generated at and transferred from a base station through fiber wrapped around the spooler, through the rotary joint, and ultimately to the power extraction system at a remote mobility platform for conversion to another form of energy.

Fiber optically isolated and remotely stabilized data transmission system

DOEpatents

Nelson, Melvin A.

1992-01-01

A fiber optically isolated and remotely stabilized data transmission system s described wherein optical data may be transmitted over an optical data fiber from a remote source which includes a data transmitter and a power supply at the remote source. The transmitter may be remotely calibrated and stabilized via an optical control fiber, and the power source may be remotely cycled between duty and standby modes via an optical control fiber.

Fiber optically isolated and remotely stabilized data transmission system

DOEpatents

Nelson, M.A.

1992-11-10

A fiber optically isolated and remotely stabilized data transmission systems described wherein optical data may be transmitted over an optical data fiber from a remote source which includes a data transmitter and a power supply at the remote source. The transmitter may be remotely calibrated and stabilized via an optical control fiber, and the power source may be remotely cycled between duty and standby modes via an optical control fiber. 3 figs.

Improved computational fluid dynamic simulations of blood flow in membrane oxygenators from X-ray imaging.

PubMed

Jones, Cameron C; McDonough, James M; Capasso, Patrizio; Wang, Dongfang; Rosenstein, Kyle S; Zwischenberger, Joseph B

2013-10-01

Computational fluid dynamics (CFD) is a useful tool in characterizing artificial lung designs by providing predictions of device performance through analyses of pressure distribution, perfusion dynamics, and gas transport properties. Validation of numerical results in membrane oxygenators has been predominantly based on experimental pressure measurements with little emphasis placed on confirmation of the velocity fields due to opacity of the fiber membrane and limitations of optical velocimetric methods. Biplane X-ray digital subtraction angiography was used to visualize flow of a blood analogue through a commercial membrane oxygenator at 1-4.5 L/min. Permeability and inertial coefficients of the Ergun equation were experimentally determined to be 180 and 2.4, respectively. Numerical simulations treating the fiber bundle as a single momentum sink according to the Ergun equation accurately predicted pressure losses across the fiber membrane, but significantly underestimated velocity magnitudes in the fiber bundle. A scaling constant was incorporated into the numerical porosity and reduced the average difference between experimental and numerical values in the porous media regions from 44 ± 4% to 6 ± 5%.

A novel fiber-optic measurement system for the evaluation of performances of neonatal pulmonary ventilators

NASA Astrophysics Data System (ADS)

Battista, L.; Scorza, A.; Botta, F.; Sciuto, S. A.

2016-02-01

Published standards for the performance evaluation of pulmonary ventilators are mainly directed to manufacturers rather than to end-users and often considered inadequate or not comprehensive. In order to contribute to overcome the problems above, a novel measurement system was proposed and tested with waveforms of mechanical ventilation by means of experimental trials carried out with infant ventilators typically used in neonatal intensive care units: the main quantities of mechanical ventilation in newborns are monitored, i.e. air flow rate, differential pressure and volume from infant ventilator are measured by means of two novel fiber-optic sensors (OFSs) developed and characterized by the authors, while temperature and relative humidity of air mass are obtained by two commercial transducers. The proposed fiber-optic sensors (flow sensor Q-OFS, pressure sensor P-OFS) showed measurement ranges of air flow and pressure typically encountered in neonatal mechanical ventilation, i.e. the air flow rate Q ranged from 3 l min-1 to 18 l min-1 (inspiratory) and from  -3 l min-1 to  -18 l min-1 (expiratory), the differential pressure ΔP ranged from  -15 cmH2O to 15 cmH2O. In each experimental trial carried out with different settings of the ventilator, outputs of the OFSs are compared with data from two reference sensors (reference flow sensor RF, reference pressure sensor RP) and results are found consistent: flow rate Q showed a maximum error between Q-OFS and RF up to 13 percent, with an output ratio Q RF/Q OFS of not more than 1.06  ±  0.09 (least square estimation, 95 percent confidence level, R 2 between 0.9822 and 0.9931). On the other hand the maximum error between P-OFS and RP on differential pressure ΔP was lower than 10 percent, with an output ratio ΔP RP/ΔP OFS between 0.977  ±  0.022 and 1.0  ±  0.8 (least square estimation, 95 percent confidence level, R 2 between 0.9864 and 0.9876). Despite the possible improvements, results were encouraging and suggested the proposed measurement system can be considered suitable for performances evaluation of neonatal ventilators and useful for both end-users and manufacturers.

On the impact of fiber-delay-lines (FDL) in an all-optical network (AON) bottleneck without wavelength conversion

NASA Astrophysics Data System (ADS)

Argibay-Losada, Pablo Jesus; Sahin, Gokhan

2014-08-01

Random access memories (RAM) are fundamental in conventional electronic switches and routers to manage short-term congestion and to decrease data loss probabilities. Switches in all-optical networks (AONs), however, do not have access to optical RAM, and therefore are prone to much higher loss levels than their electronic counterparts. Fiber-delay-lines (FDLs), able to delay an optical data packet a fixed amount of time, have been proposed in the literature as a means to alleviate those high loss levels. However, they are extremely bulky to manage, so their usage introduces a trade-off between practicality and performance in the design and operation of the AON. In this paper we study the influence that FDLs have in the performance of flows crossing an all-optical switch that acts as their bottleneck. We show how extremely low numbers of FDLs (e.g., 1 or 2) can help in reducing losses by several orders of magnitude in several illustrative scenarios with high aggregation levels. Our results therefore suggest that FDLs can be a practical means of dealing with congestion in AONs in the absence of optical RAM buffers or of suitable data interchange protocols specifically designed for AONs.

Measuring optical fiber length by use of a short-pulse optical fiber ring laser in a self-injection seeding scheme.

PubMed

Wang, Yi-Ping; Wang, Dong Ning; Jin, Wei

2006-09-01

A method for measuring the length of an optical fiber by use of an optical fiber ring laser pulse source is proposed and demonstrated. The key element of the optical fiber ring laser is a gain-switched Fabry-Perot laser diode operated in a self-injection seeding scheme. This method is especially suitable for measuring a medium or long fiber, and a resolution of 0.1 m is experimentally achieved. The measurement is implemented by accurately determining the pulse frequency that can maximize the output power of the fiber ring laser. The measurement results depend only on the refractive index of the fiber corresponding to this single wavelength, instead of the group index of the fiber, which represents a great advantage over both optical time-domain reflectometry and optical low-coherence reflectometry methods.

Fiber Optics: A New World of Possibilities in Light.

ERIC Educational Resources Information Center

Hutchinson, John

1990-01-01

The background and history of light and fiber optics are discussed. Applications for light passed either directly or indirectly through optical fibers are described. Suggestions for science activities that use fiber optics are provided. (KR)

Strain and dynamic measurements using fiber optic sensors embedded into graphite/epoxy tubes

NASA Technical Reports Server (NTRS)

Dehart, D. W.; Doederlein, T.; Koury, J.; Rogowski, R. S.; Heyman, J. S.; Holben, M. S., Jr.

1989-01-01

Graphite/epoxy tubes were fabricated with embedded optical fibers to evaluate the feasibility of monitoring strains with a fiber optic technique. Resistance strain gauges were attached to the tubes to measure strain at four locations along the tube for comparison with the fiber optic sensors. Both static and dynamic strain measurements were made with excellent agreement between the embedded fiber optic strain sensor and the strain gauges. Strain measurements of 10(exp -7) can be detected with the optical phase locked loop (OPLL) system using optical fiber. Because of their light weight, compatibility with composites, immunity to electromagnetic interference, and based on the static and dynamic results obtained, fiber optic sensors embedded in composites may be useful as the sensing component of smart structures.

A new fiber optic sensor for inner surface roughness measurement

NASA Astrophysics Data System (ADS)

Xu, Xiaomei; Liu, Shoubin; Hu, Hong

2009-11-01

In order to measure inner surface roughness of small holes nondestructively, a new fiber optic sensor is researched and developed. Firstly, a new model for surface roughness measurement is proposed, which is based on intensity-modulated fiber optic sensors and scattering modeling of rough surfaces. Secondly, a fiber optical measurement system is designed and set up. Under the help of new techniques, the fiber optic sensor can be miniaturized. Furthermore, the use of micro prism makes the light turn 90 degree, so the inner side surface roughness of small holes can be measured. Thirdly, the fiber optic sensor is gauged by standard surface roughness specimens, and a series of measurement experiments have been done. The measurement results are compared with those obtained by TR220 Surface Roughness Instrument and Form Talysurf Laser 635, and validity of the developed fiber optic sensor is verified. Finally, precision and influence factors of the fiber optic sensor are analyzed.

Fiber optic Cerenkov radiation sensor system to estimate burn-up of spent fuel: characteristic evaluation of the system using Co-60 source

NASA Astrophysics Data System (ADS)

Shin, S. H.; Jang, K. W.; Jeon, D.; Hong, S.; Kim, S. G.; Sim, H. I.; Yoo, W. J.; Park, B. G.; Lee, B.

2013-09-01

Cerenkov radiation occurs when charged particles are moving faster than the speed of light in a transparent dielectric medium. In optical fibers, the Cerenkov light also can be generated due to their dielectric components. Accordingly, the radiation-induced light signals can be obtained using optical fibers without any scintillating material. In this study, to measure the intensities of Cerenkov radiation induced by gamma-rays, we have fabricated the fiber-optic Cerenkov radiation sensor system using silica optical fibers, plastic optical fibers, multi-anode photomultiplier tubes, and a scanning system. To characterize the Cerenkov radiation generated in optical fibers, the spectra of Cerenkov radiation generated in the silica and plastic optical fibers were measured. Also, the intensities of Cerenkov radiation induced by gamma-rays generated from a cylindrical Co-60 source with or without lead shielding were measured using the fiberoptic Cerenkov radiation sensor system.

FIBER OPTICS: Polarization phase nonreciprocity in all-fiber ring interferometers

NASA Astrophysics Data System (ADS)

Andreev, A. Ts; Vasilev, V. D.; Kozlov, V. A.; Kuznetsov, A. V.; Senatorov, A. A.; Shubochkin, R. L.

1993-08-01

The polarization phase nonreciprocity in all-fiber ring interferometers based on single-mode optical fibers was studied experimentally. The results confirm existing theoretical models. Experimentally, it was possible to use fiber ring interferometers to measure the extinction coefficients of optical fiber polarizers. The largest extinction coefficients found for optical-fiber polarizers were 84 dB (for the wavelength 0.82 μm) and 86 dB (1.3 μm).

Fiber optic sensors and systems at the Federal University of Rio de Janeiro

NASA Astrophysics Data System (ADS)

Werneck, Marcelo M.; dos Santos, Paulo A. M.; Ferreira, Aldo P.; Maggi, Luis E.; de Carvalho, Carlos R., Jr.; Ribeiro, R. M.

1998-08-01

As widely known, fiberoptics (FO) are being used in a large variety of sensors and systems particularly for their small dimensions and low cost, large bandwidth and favorable dielectric properties. These properties have allowed us to develop sensors and systems for general applications and, particularly, for biomedical engineering. The intravascular pressure sensor was designed for small dimensions and high bandwidth. The system is based on light-intensity modulation technique and uses a 2 mm-diameter elastomer membrane as the sensor element and a pigtailed laser as a light source. The optical power output curve was linear for pressures within the range of 0 to 300 mmHg. The real time optical biosensor uses the evanescent field technique for monitoring Escherichia coli growth in culture media. The optical biosensor monitors interactions between the analytic (bacteria) and the evanescent field of an optical fiber passing through it. The FO based high voltage and current sensor is a measuring system designed for monitoring voltage and current in high voltage transmission lines. The linearity of the system is better than 2% in both ranges of 0 to 25 kV and 0 to 1000 A. The optical flowmeter uses a cross-correlation technique that analyses two light beams crossing the flow separated by a fixed distance. The x-ray image sensor uses a scintillating FO array, one FO for each image pixel to form an image of the x-ray field. The systems described in these paper use general-purpose components including optical fibers and optoelectronic devices, which are readily available, and of low cost.

Research progress in fiber optic sensors and systems at the Federal University of Rio de Janeiro

NASA Astrophysics Data System (ADS)

Werneck, Marcelo M.; Ferreira, Aldo P.; Maggi, Luis E.; De Carvalho, C. C.; Ribeiro, R. M.

1999-02-01

As widely known, fiberoptics (FO) are being used in a large variety of sensor an systems particularly for their small dimensions and low cost, large bandwidth and favorable dielectric properties. These properties have allowed us to develop sensor and systems for general applications and, particularly, for biomedical engineering. The intravasculator pressure sensor was designed for small dimensions and high bandwidth. The system is based on light- intensity modulation technique and use a 2 mm-diameter elastomer membrane as the sensor element and a pigtailed laser as a light source. The optical power out put curve was linear for pressures within the range of 0 to 300 mmHg. The real time optical biosensor uses the evanescent field technique for monitoring Escherichia coli growth in culture media. The optical biosensor monitors interactions between the analytic and the evanescent field of an optical fiber passing through it. The FO based high voltage and current sensor is a measuring system designed for monitoring voltage and current in high voltage transmission lines. The linearity of the system is better than 2 percent in both ranges of 0 to 25 kV and 0 to 1000 A. The optical flowmeter uses a cross-correlation technique that analyzes two light beams crossing the flow separated by a fixed distance. The x-ray image sensor uses a scintillating FO array, one FO for each image pixel to form an image of the x-ray field. The systems described in this paper use general-purpose components including optical fibers and optoelectronic devices, which are readily available, and of low cost.

Microbend fiber-optic temperature sensor

DOEpatents

Weiss, J.D.

1995-05-30

A temperature sensor is made of optical fiber into which quasi-sinusoidal microbends have been permanently introduced. In particular, the present invention includes a graded-index optical fiber directing steady light through a section of the optical fiber containing a plurality of permanent microbends. The microbend section of the optical fiber is contained in a thermally expansive sheath, attached to a thermally expansive structure, or attached to a bimetallic element undergoing temperature changes and being monitored. The microbend section is secured to the thermally expansive sheath which allows the amplitude of the microbends to decrease with temperature. The resultant increase in the optical fiber`s transmission thus allows temperature to be measured. The plural microbend section of the optical fiber is secured to the thermally expansive structure only at its ends and the microbends themselves are completely unconstrained laterally by any bonding agent to obtain maximum longitudinal temperature sensitivity. Although the permanent microbends reduce the transmission capabilities of fiber optics, the present invention utilizes this phenomenon as a transduction mechanism which is optimized to measure temperature. 5 figs.

High pressure fiber optic sensor system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guida, Renato; Xia, Hua; Lee, Boon K

2013-11-26

The present application provides a fiber optic sensor system. The fiber optic sensor system may include a small diameter bellows, a large diameter bellows, and a fiber optic pressure sensor attached to the small diameter bellows. Contraction of the large diameter bellows under an applied pressure may cause the small diameter bellows to expand such that the fiber optic pressure sensor may measure the applied pressure.

Embedding Optical Fibers In Cast Metal Parts

NASA Technical Reports Server (NTRS)

Gibler, William N.; Atkins, Robert A.; Lee, Chung E.; Taylor, Henry F.

1995-01-01

Use of metal strain reliefs eliminates breakage of fibers during casting process. Technique for embedding fused silica optical fibers in cast metal parts devised. Optical fiber embedded in flange, fitting, or wall of vacuum or pressure chamber, to provide hermetically sealed feedthrough for optical transmission of measurement or control signals. Another example, optical-fiber temperature sensor embedded in metal structural component to measure strain or temperature inside component.

Optical fiber characteristics and standards; Proceedings of the Meeting, Cannes, France, November 25-27, 1985

NASA Technical Reports Server (NTRS)

Bouillie, Remy (Editor)

1986-01-01

Papers are presented on outside vapor deposition, the plasma activated CVD process for large scale production of telecommunication fibers, axial lateral plasma deposition technology from plastic clad silica, coatings for optical fibers, primary coating characterization, and radiation-induced time dependent attenuation in a fiber. Topics discussed include fibers with high tensile strength, the characteristics and specifications of airborne fiber optic components, the baseband frequency response of multimode fibers, and fibers for local and broadband networks. Consideration is given to industrial measurements for single mode and multimode fibers, the characterization of source power distribution in a multimode fiber by a splice offset technique, the measurement of chromatic dispersion in a single mode optical, and the effect of temperature on the refracted near-field optical fiber profiling technique.

Using a slightly tapered optical fiber to attract and transport microparticles.

PubMed

Sheu, Fang-Wen; Wu, Hong-Yu; Chen, Sy-Hann

2010-03-15

We exploit a fiber puller to transform a telecom single-mode optical fiber with a 125 microm diameter into a symmetric and unbroken slightly tapered optical fiber with a 50 microm diameter at the minimum waist. When the laser light is launched into the optical fiber, we can observe that, due to the evanescent wave of the slightly tapered fiber, the nearby polystyrene microparticles with 10 microm diameters will be attracted onto the fiber surface and roll separately in the direction of light propagation. We have also simulated and compared the optical propulsion effects on the microparticles when the laser light is launched into a slightly tapered fiber and a heavily tapered (subwavelength) fiber, respectively.

Fiber-optic Singlet Oxygen [1O2 (1Δg)] Generator Device Serving as a Point Selective Sterilizer

PubMed Central

Aebisher, David; Zamadar, Matibur; Mahendran, Adaickapillai; Ghosh, Goutam; McEntee, Catherine; Greer, Alexander

2016-01-01

Traditionally, Type II heterogeneous photo-oxidations produce singlet oxygen via external irradiation of a sensitizer and external supply of ground-state oxygen. A potential improvement is reported here. A hollow-core fiber-optic device was developed with an “internal” supply of light and flowing oxygen, and a porous photosensitizer-end capped configuration. Singlet oxygen was delivered through the fiber tip. The singlet oxygen steady-state concentration in the immediate vicinity of the probe tip was ca 20 fM by N-benzoyl-DL-methionine trapping. The device is portable and the singlet oxygen-generating tip is maneuverable, which opened the door to simple disinfectant studies. Complete Escherichia coli inactivation was observed in 2 h when the singlet oxygen sensitizing probe tip was immersed in 0.1 mL aqueous samples of 0.1–4.4 × 107 cells. Photobleaching of the probe tip occurred after ca 12 h of use, requiring baking and sensitizer reloading steps for reuse. PMID:20497367

Selenium semiconductor core optical fibers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, G. W.; Qian, Q., E-mail: qianqi@scut.edu.cn; Peng, K. L.

2015-02-15

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

Silicon-on-insulator multimode-interference waveguide-based arrayed optical tweezers (SMART) for two-dimensional microparticle trapping and manipulation.

PubMed

Lei, Ting; Poon, Andrew W

2013-01-28

We demonstrate two-dimensional optical trapping and manipulation of 1 μm and 2.2 μm polystyrene particles in an 18 μm-thick fluidic cell at a wavelength of 1565 nm using the recently proposed Silicon-on-insulator Multimode-interference (MMI) waveguide-based ARrayed optical Tweezers (SMART) technique. The key component is a 100 μm square-core silicon waveguide with mm length. By tuning the fiber-coupling position at the MMI waveguide input facet, we demonstrate various patterns of arrayed optical tweezers that enable optical trapping and manipulation of particles. We numerically simulate the physical mechanisms involved in the arrayed trap, including the optical force, the heat transfer and the thermal-induced microfluidic flow.

7 CFR 1755.404 - Fiber optic cable telecommunications plant measurements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... performed on each optical fiber within the cable. (2) Method of measurement. For single mode fibers, the end-to-end attenuation measurements of each optical fiber at 1310 and/or 1550 nanometers in each...-end attenuation of each single mode optical fiber at 1310 and/or 1550 nanometers shall not exceed the...

7 CFR 1755.404 - Fiber optic cable telecommunications plant measurements.

Code of Federal Regulations, 2014 CFR

2014-01-01

... performed on each optical fiber within the cable. (2) Method of measurement. For single mode fibers, the end-to-end attenuation measurements of each optical fiber at 1310 and/or 1550 nanometers in each...-end attenuation of each single mode optical fiber at 1310 and/or 1550 nanometers shall not exceed the...

7 CFR 1755.404 - Fiber optic cable telecommunications plant measurements.

Code of Federal Regulations, 2012 CFR

2012-01-01

... performed on each optical fiber within the cable. (2) Method of measurement. For single mode fibers, the end-to-end attenuation measurements of each optical fiber at 1310 and/or 1550 nanometers in each...-end attenuation of each single mode optical fiber at 1310 and/or 1550 nanometers shall not exceed the...

Large core fiber optic cleaver

DOEpatents

Halpin, John M.

1996-01-01

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

Optical fibers for the distribution of frequency and timing references

NASA Technical Reports Server (NTRS)

Lutes, G. F.

1981-01-01

An optical fiber communications link was installed for the purpose of evaluating the applicability of optical fiber technology to the distribution of frequency and timing reference signals. It incorporated a 1.5km length of optical fiber cable containing two multimode optical fibers. The two fibers were welded together at one end of the cable to attain a path length of 3km. Preliminary measurements made on this link, including Allan variance and power spectral density of phase noise are reported.

High-temperature optical fiber instrumentation for gas flow monitoring in gas turbine engines

NASA Astrophysics Data System (ADS)

Roberts, Adrian; May, Russell G.; Pickrell, Gary R.; Wang, Anbo

2002-02-01

In the design and testing of gas turbine engines, real-time data about such physical variables as temperature, pressure and acoustics are of critical importance. The high temperature environment experienced in the engines makes conventional electronic sensors devices difficult to apply. Therefore, there is a need for innovative sensors that can reliably operate under the high temperature conditions and with the desirable resolution and frequency response. A fiber optic high temperature sensor system for dynamic pressure measurement is presented in this paper. This sensor is based on a new sensor technology - the self-calibrated interferometric/intensity-based (SCIIB) sensor, recently developed at Virginia Tech. State-of-the-art digital signal processing (DSP) methods are applied to process the signal from the sensor to acquire high-speed frequency response.

An interferometer having fused optical fibers, and apparatus and method using the interferometer

NASA Technical Reports Server (NTRS)

Hellbaum, Richard F. (Inventor); Claus, Richard O. (Inventor); Murphy, Kent A. (Inventor); Gunther, Michael F. (Inventor)

1992-01-01

An interferometer includes a first optical fiber coupled to a second optical fiber by fusing. At a fused portion, the first and second optical fibers are cut to expose respective cores. The cut or fused end of the first and second optical fibers is arranged to oppose a diaphragm or surface against which a physical phenomenon such as pressure or stress, is applied. In a first embodiment, a source light which is generally single-mode monochromatic, coherent light, is input to the first optical fiber and by evanescence, effectively crosses to the second optical fiber at the fused portion. Source light from the second optical fiber is reflected by the diaphragm or surface, and received at the second optical fiber to generate an output light which has an intensity which depends upon interference of reference light based on the source light, and the reflected light reflected from the diaphragm or surface. The intensity of the output light represents a positional relationship or displacement between the interferometer and the diaphragm or surface.

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

PubMed

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

2013-07-29

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

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

NASA Astrophysics Data System (ADS)

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

2009-03-01

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

Fiber optic probes for laser light scattering: Ground based evaluation for micgrogravity flight experimentation. Integrated coherent imaging fiber optic systems for laser light scattering and other applications

NASA Technical Reports Server (NTRS)

Dhadwal, Harbans Singh

1994-01-01

The research work presented in this report has established a new class of backscatter fiber optics probes for remote dynamic light scattering capability over a range of scattering angles from 94 degrees to 175 degrees. The fiber optic probes provide remote access to scattering systems, and can be utilized in either a noninvasive or invasive configuration. The fiber optics create an interference free data channel to inaccessible and harsh environments. Results from several studies of concentrated suspension, microemulsions, and protein systems are presented. The second part of the report describes the development of a new technology of wavefront processing within the optical fiber, that is, integrated fiber optics. Results have been very encouraging and the technology promises to have significant impact on the development of fiber optic sensors in a variety of fields ranging from environmental monitoring to optical recording, from biomedical sensing to photolithography.

Fiber Optic Experience with the Smart Actuation System on the F-18 Systems Research Aircraft

NASA Technical Reports Server (NTRS)

Zavala, Eddie

1997-01-01

High bandwidth, immunity to electromagnetic interference, and potential weight savings have led to the development of fiber optic technology for future aerospace vehicle systems. This technology has been incorporated in a new smart actuator as the primary communication interface. The use of fiber optics simplified system integration and significantly reduced wire count. Flight test results showed that fiber optics could be used in aircraft systems and identified critical areas of development of fly-by-light technology. This paper documents the fiber optic experience gained as a result of this program, and identifies general design considerations that could be used in a variety of specific applications of fiber optic technology. Environmental sensitivities of fiber optic system components that significantly contribute to optical power variation are discussed. Although a calibration procedure successfully minimized the effect of fiber optic sensitivities, more standardized calibration methods are needed to ensure system operation and reliability in future aerospace vehicle systems.

Multinational Counter-Piracy Operations: How Strategically Significant is the Gulf of Guinea to the Major Maritime Powers

DTIC Science & Technology

2015-12-01

DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words ) Piracy in the Gulf of Guinea regularly exceeded that of the Gulf of Aden between 2000 and 2007. But...flow of goods is the flow of services, which in today’s computer-centric world travels electronically in digital bits and bytes through fiber optic...piracy prosecutions, among others. Second order costs include fisheries, food security and food price inflation, tourism , and environmental pollution

KSC-02pd1130

NASA Image and Video Library

2002-07-10

KENNEDY SPACE CENTER, FLA. -- With the engines removed from Endeavour, the flow line can be inspected. On the right, Gerry Kathka, with United Space Alliance, hands part of a fiber-optic camera system to Scott Minnick, left. Minnick wears a special viewing apparatus that sees where the camera is going. The inspection is the result of small cracks being discovered on the LH2 Main Propulsion System (MPS) flow liners in other orbiters. Endeavour is next scheduled to fly on mission STS-113.

Ion flow measurements during the rotating kink behavior of the central column in the HIST device

NASA Astrophysics Data System (ADS)

Yamada, S.; Yoshikawa, T.; Hashimoto, S.; Nishioka, T.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

2007-11-01

Plasma flow is essentially driven in self-organization and magnetic reconnection process of compact spherical torus (ST) and spheromak in the helicity-driven systems. For example, when reversing the external toroidal field of ST, the direction not only of the plasma current but also of the toroidal ion flow is self-reversed during the formation of the flipped ST relaxed states. Mach probe measurement shows that the velocity of the ion flow reversed after the flip increases to about 20 km/s. We have been newly developing an ion Doppler spectrometer (IDS) system using a compact 16 or 64 channel photomultiplier tube (PMT) in order to measure the spatial profile of ion temperature and rotation velocity in the HIST device. The IDS system consists of a light collection system including optical fibers, 1 m-spectrometer and the PMT detector. The optical fibers covered with glass tubes are inserted into the plasma. The glass tubes can be rotated in the poloidal and the toroidal directions. The new IDS system will be applied to observations of ion temperature and plasma rotation in the flipped ST formation and in the MHD control of kinking behaviors of the central column by using the rotating magnetic field (RMF). Preliminary IDS results will be compared to those from Mach probe measurements in space.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shiquan Tao

2006-12-31

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

Effect of soil temperature on optical frequency transfer through unidirectional dense-wavelength-division-multiplexing fiber-optic links.

PubMed

Pinkert, T J; Böll, O; Willmann, L; Jansen, G S M; Dijck, E A; Groeneveld, B G H M; Smets, R; Bosveld, F C; Ubachs, W; Jungmann, K; Eikema, K S E; Koelemeij, J C J

2015-02-01

Results of optical frequency transfer over a carrier-grade dense-wavelength-division-multiplexing (DWDM) optical fiber network are presented. The relation between soil temperature changes on a buried optical fiber and frequency changes of an optical carrier through the fiber is modeled. Soil temperatures, measured at various depths by the Royal Netherlands Meteorology Institute (KNMI) are compared with observed frequency variations through this model. A comparison of a nine-day record of optical frequency measurements through the 2×298  km fiber link with soil temperature data shows qualitative agreement. A soil temperature model is used to predict the link stability over longer periods (days-months-years). We show that optical frequency dissemination is sufficiently stable to distribute and compare, e.g., rubidium frequency standards over standard DWDM optical fiber networks using unidirectional fibers.

Novel Fiber-Optic Ring Acoustic Emission Sensor

PubMed Central

Han, Xiaole; Xia, Dong; Liu, Taolin; Lang, Hao

2018-01-01

Acoustic emission technology has been applied to many fields for many years. However, the conventional piezoelectric acoustic emission sensors cannot be used in extreme environments, such as those with heavy electromagnetic interference, high pressure, or strong corrosion. In this paper, a novel fiber-optic ring acoustic emission sensor is proposed. The sensor exhibits high sensitivity, anti-electromagnetic interference, and corrosion resistance. First, the principle of a novel fiber-optic ring sensor is introduced. Different from piezoelectric and other fiber acoustic emission sensors, this novel sensor includes both a sensing skeleton and a sensing fiber. Second, a heterodyne interferometric demodulating method is presented. In addition, a fiber-optic ring sensor acoustic emission system is built based on this method. Finally, fiber-optic ring acoustic emission experiments are performed. The novel fiber-optic ring sensor is glued onto the surface of an aluminum plate. The 150 kHz standard continuous sinusoidal signals and broken lead signals are successfully detected by the novel fiber-optic ring acoustic emission sensor. In addition, comparison to the piezoelectric acoustic emission sensor is performed, which shows the availability and reliability of the novel fiber-optic ring acoustic emission sensor. In the future, this novel fiber-optic ring acoustic emission sensor will provide a new route to acoustic emission detection in harsh environments. PMID:29342858

Novel Fiber-Optic Ring Acoustic Emission Sensor.

PubMed

Wei, Peng; Han, Xiaole; Xia, Dong; Liu, Taolin; Lang, Hao

2018-01-13

Acoustic emission technology has been applied to many fields for many years. However, the conventional piezoelectric acoustic emission sensors cannot be used in extreme environments, such as those with heavy electromagnetic interference, high pressure, or strong corrosion. In this paper, a novel fiber-optic ring acoustic emission sensor is proposed. The sensor exhibits high sensitivity, anti-electromagnetic interference, and corrosion resistance. First, the principle of a novel fiber-optic ring sensor is introduced. Different from piezoelectric and other fiber acoustic emission sensors, this novel sensor includes both a sensing skeleton and a sensing fiber. Second, a heterodyne interferometric demodulating method is presented. In addition, a fiber-optic ring sensor acoustic emission system is built based on this method. Finally, fiber-optic ring acoustic emission experiments are performed. The novel fiber-optic ring sensor is glued onto the surface of an aluminum plate. The 150 kHz standard continuous sinusoidal signals and broken lead signals are successfully detected by the novel fiber-optic ring acoustic emission sensor. In addition, comparison to the piezoelectric acoustic emission sensor is performed, which shows the availability and reliability of the novel fiber-optic ring acoustic emission sensor. In the future, this novel fiber-optic ring acoustic emission sensor will provide a new route to acoustic emission detection in harsh environments.

Large core fiber optic cleaver

DOEpatents

Halpin, J.M.

1996-03-26

The present invention relates to a device and method for cleaving optical fibers which yields cleaved optical fiber ends possessing high damage threshold surfaces. The device can be used to cleave optical fibers with core diameters greater than 400 {micro}m. 30 figs.

Noninvasive blood pressure measurement scheme based on optical fiber sensor

NASA Astrophysics Data System (ADS)

Liu, Xianxuan; Yuan, Xueguang; Zhang, Yangan

2016-10-01

Optical fiber sensing has many advantages, such as volume small, light quality, low loss, strong in anti-jamming. Since the invention of the optical fiber sensing technology in 1977, optical fiber sensing technology has been applied in the military, national defense, aerospace, industrial, medical and other fields in recent years, and made a great contribution to parameter measurement in the environment under the limited condition .With the rapid development of computer, network system, the intelligent optical fiber sensing technology, the sensor technology, the combination of computer and communication technology , the detection, diagnosis and analysis can be automatically and efficiently completed. In this work, we proposed a noninvasive blood pressure detection and analysis scheme which uses optical fiber sensor. Optical fiber sensing system mainly includes the light source, optical fiber, optical detector, optical modulator, the signal processing module and so on. wavelength optical signals were led into the optical fiber sensor and the signals reflected by the human body surface were detected. By comparing actual testing data with the data got by traditional way to measure the blood pressure we can establish models for predicting the blood pressure and achieve noninvasive blood pressure measurement by using spectrum analysis technology. Blood pressure measurement method based on optical fiber sensing system is faster and more convenient than traditional way, and it can get accurate analysis results in a shorter period of time than before, so it can efficiently reduce the time cost and manpower cost.

Optical fiber strain sensor with improved linearity range

NASA Technical Reports Server (NTRS)

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

1995-01-01

A strain sensor is constructed from a two mode optical fiber. When the optical fiber is surface mounted in a straight line and the object to which the optical fiber is mounted is subjected to strain within a predetermined range, the light intensity of any point at the output of the optical fiber will have a linear relationship to strain, provided the intermodal phase difference is less than 0.17 radians.

Probe Without Moving Parts Measures Flow Angle

NASA Technical Reports Server (NTRS)

Corda, Stephen; Vachon, M. Jake

2003-01-01

The measurement of local flow angle is critical in many fluid-dynamic applications, including the aerodynamic flight testing of new aircraft and flight systems. Flight researchers at NASA Dryden Flight Research Center have recently developed, flight-tested, and patented the force-based flow-angle probe (FLAP), a novel, force-based instrument for the measurement of local flow direction. Containing no moving parts, the FLAP may provide greater simplicity, improved accuracy, and increased measurement access, relative to conventional moving vane-type flow-angle probes. Forces in the FLAP can be measured by various techniques, including those that involve conventional strain gauges (based on electrical resistance) and those that involve more advanced strain gauges (based on optical fibers). A correlation is used to convert force-measurement data to the local flow angle. The use of fiber optics will enable the construction of a miniature FLAP, leading to the possibility of flow measurement in very small or confined regions. This may also enable the tufting of a surface with miniature FLAPs, capable of quantitative flow-angle measurements, similar to attaching yarn tufts for qualitative measurements. The prototype FLAP was a small, aerodynamically shaped, low-aspect-ratio fin about 2 in. (approximately equal to 5 cm) long, 1 in. (approximately equal to 2.5 cm) wide, and 0.125 in. (approximately equal to 0.3 cm) thick (see Figure 1). The prototype FLAP included simple electrical-resistance strain gauges for measuring forces. Four strain gauges were mounted on the FLAP; two on the upper surface and two on the lower surface. The gauges were connected to form a full Wheatstone bridge, configured as a bending bridge. In preparation for a flight test, the prototype FLAP was mounted on the airdata boom of a flight-test fixture (FTF) on the NASA Dryden F-15B flight research airplane.

High-accuracy fiber-optic shape sensing

NASA Astrophysics Data System (ADS)

Duncan, Roger G.; Froggatt, Mark E.; Kreger, Stephen T.; Seeley, Ryan J.; Gifford, Dawn K.; Sang, Alexander K.; Wolfe, Matthew S.

2007-04-01

We describe the results of a study of the performance characteristics of a monolithic fiber-optic shape sensor array. Distributed strain measurements in a multi-core optical fiber interrogated with the optical frequency domain reflectometry technique are used to deduce the shape of the optical fiber; referencing to a coordinate system yields position information. Two sensing techniques are discussed herein: the first employing fiber Bragg gratings and the second employing the intrinsic Rayleigh backscatter of the optical fiber. We have measured shape and position under a variety of circumstances and report the accuracy and precision of these measurements. A discussion of error sources is included.

[Optical-fiber Fourier transform spectrometer].

PubMed

Liu, Yong; Li, Bao-sheng; Liu, Yan; Zhai, Yu-feng; Wang, An

2006-10-01

A novel Fourier transform spectrum analyzer based on a single mode fiber Mach-Zehnder interferometer is reported. An optical fiber Fourier transform spectrometer, with bulk optics components replaced by fiber optical components and with the moving mirror replaced by a piezoelectric element fiber stretcher was constructed. The output spectrum of a LD below threshold was measured. Experiment result agrees with that by using grating spectrum analyzer, showing the feasibility of the optic fiber Fourier transform spectrometer for practical spectrum measurement. Spectrum resolution -7 cm(-1) was obtained in our experiment. The resolution can be further improved by increasing the maximum optical path difference.

Wavefront Processing Through Integrated Fiber Optics.

NASA Astrophysics Data System (ADS)

Khan, Romel Rabiul

This thesis is devoted to the development of a new technology of integrated fiber optics. Through the use of fusion splicing and etching several dissimilar optical fibers can be integrated into a single fiber providing wave-front processing capabilities not previously possible. Optical fibers have been utilized for their unique capabilities; such as, remote beam delivery and immunity from electromagnetic noise. In this thesis, the understanding of integrated fiber optics through fusion splicing is furthered both theoretically and experimentally. Most of the common optical components such as lenses, apertures, and modulators can be implemented through the use of fiber optics and then integrated together through fusion splicing, resulting in an alignment-free, rugged and miniaturized system. For example, a short length of multimode graded-index fiber can be used as either a lens or a window to relay an image. A step-index multimode fiber provides a spacer or an aperture. Other special arrangements can be exploited to do in-line modulation in both amplitude and phase. The power of this technique is demonstrated by focusing on a few applications where significant advantages are obtained through this technology. In laser light scattering fiber optic systems, integrated fiber optics is used for delivering and receiving light from small scattering volumes in a spatially constrained environment. When applied for the detection of cataracts in the human eye lens, laser light scattering probes with integrated fiber optics could obtain a map of the eye lens and provide invaluable data for further understanding of cataractogenesis. Use of integrated fiber optics in the high resolution structural analysis of aircraft propeller blades is also presented. Coupling of laser diode to monomode fiber through integrated fiber optics is analyzed. The generation of nondiffracting Bessel-Gauss beams using integrated fiber optics is described. The significance of the Bessel-Gauss beam lies in the fact that it has a sharply defined main-lobe whose width can be designed to be as narrow as desired, while maintaining a long propagation-invariant range. Different methods of generation and properties of this beam are reviewed. Effects of misalignments in the input plane and discretization of the source are derived and evaluated.

Fiber optic in vivo imaging in the mammalian nervous system

PubMed Central

Mehta, Amit D; Jung, Juergen C; Flusberg, Benjamin A; Schnitzer, Mark J

2010-01-01

The compact size, mechanical flexibility, and growing functionality of optical fiber and fiber optic devices are enabling several new modalities for imaging the mammalian nervous system in vivo. Fluorescence microendoscopy is a minimally invasive fiber modality that provides cellular resolution in deep brain areas. Diffuse optical tomography is a non-invasive modality that uses assemblies of fiber optic emitters and detectors on the cranium for volumetric imaging of brain activation. Optical coherence tomography is a sensitive interferometric imaging technique that can be implemented in a variety of fiber based formats and that might allow intrinsic optical detection of brain activity at a high resolution. Miniaturized fiber optic microscopy permits cellular level imaging in the brains of behaving animals. Together, these modalities will enable new uses of imaging in the intact nervous system for both research and clinical applications. PMID:15464896

Microstructured optical fiber-based luminescent biosensing: Is there any light at the end of the tunnel? - A review.

PubMed

Pidenko, Sergey A; Burmistrova, Natalia A; Shuvalov, Andrey A; Chibrova, Anastasiya A; Skibina, Yulia S; Goryacheva, Irina Y

2018-08-17

This review covers the current state of the art of luminescent biosensors based on various types of microstructured optical fiber. The unique optical and structural properties of this type of optical fiber make them one of the most promising integrated platforms for bioassays. The individual sections of this review are devoted to a) classification of microstructured optical fibers, b) microstructured optical fiber materials, c) aspects of biosensing based on the biomolecules incorporated into the microstructured optical fibers, and d) development of models for prediction of the efficiency of luminescent signal processing. The authors' views on current trends and limitations of microstructured optical fibers for biosensing as well as the most promising areas and technologies for application in analytical practice are presented. Copyright © 2017 Elsevier B.V. All rights reserved.

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

PubMed Central

Wang, Chuji

2009-01-01

Fiber loop ringdown (FLRD) utilizes an inexpensive telecommunications light source, a photodiode, and a section of single-mode fiber to form a uniform fiber optic sensor platform for sensing various quantities, such as pressure, temperature, strain, refractive index, chemical species, biological cells, and small volume of fluids. In FLRD, optical losses of a light pulse in a fiber loop induced by changes in a quantity are measured by the light decay time constants. FLRD measures time to detect a quantity; thus, FLRD is referred to as a time-domain sensing technique. FLRD sensors have near real-time response, multi-pass enhanced high-sensitivity, and relatively low cost (i.e., without using an optical spectral analyzer). During the last eight years since the introduction of the original form of fiber ringdown spectroscopy, there has been increasing interest in the FLRD technique in fiber optic sensor developments, and new application potential is being explored. This paper first discusses the challenging issues in development of multi-function, fiber optic sensors or sensor networks using current fiber optic sensor sensing schemes, and then gives a review on current fiber optic sensor development using FLRD technique. Finally, design perspectives on new generation, multi-function, fiber optic sensor platforms using FLRD technique are particularly presented. PMID:22408471

Fiber-optic multiphoton flow cytometry in whole blood and in vivo

NASA Astrophysics Data System (ADS)

Chang, Yu-Chung; Ye, Jing Yong; Thomas, Thommey P.; Cao, Zhengyi; Kotlyar, Alina; Tkaczyk, Eric R.; Baker, James R.; Norris, Theodore B.

2010-07-01

Circulating tumor cells in the bloodstream are sensitive indicators for metastasis and disease prognosis. Circulating cells have usually been monitored via extraction from blood, and more recently in vivo using free-space optics; however, long-term intravital monitoring of rare circulating cells remains a major challenge. We demonstrate the application of a two-photon-fluorescence optical fiber probe for the detection of cells in whole blood and in vivo. A double-clad fiber was used to enhance the detection sensitivity. Two-channel detection was employed to enable simultaneous measurement of multiple fluorescent markers. Because the fiber probe circumvents scattering and absorption from whole blood, the detected signal strength from fluorescent cells was found to be similar in phosphate-buffered saline (PBS) and in whole blood. The detection efficiency of cells labeled with the membrane-binding dye 1,1'-dioctadecyl-3,3,3',3'-tetramethylindoldicarbocyanine, 4-chlorobenzenesulfonate (DiD) was demonstrated to be the same in PBS and in whole blood. A high detection efficiency of green fluorescent protein (GFP)-expressing cells in whole blood was also demonstrated. To characterize in vivo detection, DiD-labeled untransfected and GFP-transfected cells were injected into live mice, and the cell circulation dynamics was monitored in real time. The detection efficiency of GFP-expressing cells in vivo was consistent with that observed ex vivo in whole blood.

Specialty fibers for fiber optic sensor application

NASA Astrophysics Data System (ADS)

Bennett, K.; Koh, J.; Coon, J.; Chien, C. K.; Artuso, A.; Chen, X.; Nolan, D.; Li, M.-J.

2007-09-01

Over the last several years, Fiber Optic Sensor (FOS) applications have seen an increased acceptance in many areas including oil & gas production monitoring, gyroscopes, current sensors, structural sensing and monitoring, and aerospace applications. High level optical and mechanical reliability of optical fiber is necessary to guarantee reliable performance of FOS. In this paper, we review recent research and development activities on new specialty fibers. We discuss fiber design concepts and present both modeling and experimental results. The main approaches to enhancing fiber attributes include new index profile design and fiber coating modification.

NASA Tech Briefs, February 2008

NASA Technical Reports Server (NTRS)

2008-01-01

Topics discussed include: Optical Measurement of Mass Flow of a Two-Phase Fluid; Selectable-Tip Corrosion-Testing Electrochemical Cell; Piezoelectric Bolt Breakers and Bolt Fatigue Testers; Improved Measurement of B(sub 22) of Macromolecules in a Flow Cell; Measurements by a Vector Network Analyzer at 325 to 508 GHz; Using Light to Treat Mucositis and Help Wounds Heal; Increasing Discharge Capacities of Li-(CF)(sub n) Cells; Dot-in-Well Quantum-Dot Infrared Photodetectors; Integrated Microbatteries for Implantable Medical Devices; Oxidation Behavior of Carbon Fiber-Reinforced Composites; GIDEP Batching Tool; Generic Spacecraft Model for Real-Time Simulation; Parallel-Processing Software for Creating Mosaic Images; Software for Verifying Image-Correlation Tie Points; Flexcam Image Capture Viewing and Spot Tracking; Low-Pt-Content Anode Catalyst for Direct Methanol Fuel Cells; Graphite/Cyanate Ester Face Sheets for Adaptive Optics; Atomized BaF2-CaF7 for Better-Flowing Plasma-Spray Feedstock; Nanophase Nickel-Zirconium Alloys for Fuel Cells; Vacuum Packaging of MEMS With Multiple Internal Seal Rings; Compact Two-Dimensional Spectrometer Optics; and Fault-Tolerant Coding for State Machines.

Buying Fiber-Optic Networks.

ERIC Educational Resources Information Center

Fickes, Michael

2003-01-01

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

Package for integrated optic circuit and method

DOEpatents

Kravitz, Stanley H.; Hadley, G. Ronald; Warren, Mial E.; Carson, Richard F.; Armendariz, Marcelino G.

1998-01-01

A structure and method for packaging an integrated optic circuit. The package comprises a first wall having a plurality of microlenses formed therein to establish channels of optical communication with an integrated optic circuit within the package. A first registration pattern is provided on an inside surface of one of the walls of the package for alignment and attachment of the integrated optic circuit. The package in one embodiment may further comprise a fiber holder for aligning and attaching a plurality of optical fibers to the package and extending the channels of optical communication to the fibers outside the package. In another embodiment, a fiber holder may be used to hold the fibers and align the fibers to the package. The fiber holder may be detachably connected to the package.

Package for integrated optic circuit and method

DOEpatents

Kravitz, S.H.; Hadley, G.R.; Warren, M.E.; Carson, R.F.; Armendariz, M.G.

1998-08-04

A structure and method are disclosed for packaging an integrated optic circuit. The package comprises a first wall having a plurality of microlenses formed therein to establish channels of optical communication with an integrated optic circuit within the package. A first registration pattern is provided on an inside surface of one of the walls of the package for alignment and attachment of the integrated optic circuit. The package in one embodiment may further comprise a fiber holder for aligning and attaching a plurality of optical fibers to the package and extending the channels of optical communication to the fibers outside the package. In another embodiment, a fiber holder may be used to hold the fibers and align the fibers to the package. The fiber holder may be detachably connected to the package. 6 figs.

Micro-LiDAR velocity, temperature, density, concentration sensor

NASA Technical Reports Server (NTRS)

Dorrington, Adrian A. (Inventor); Danehy, Paul M. (Inventor)

2010-01-01

A light scatter sensor includes a sensor body in which are positioned a plurality of optical fibers. The sensor body includes a surface, in one end of each of the optical fibers terminates at the surface of the sensor body. One of the optical fibers is an illumination fiber for emitting light. A plurality of second optical fibers are collection fibers for collecting scattered light signals. A light sensor processor is connected to the collection fibers to detect the scattered light signals.

Microstructured Optical Fiber for X-ray Detection

NASA Technical Reports Server (NTRS)

DeHaven, Stanton L.

2009-01-01

A novel scintillating optical fiber is presented using a composite micro-structured quartz optical fiber. Scintillating materials are introduced into the multiple inclusions of the fiber. This creates a composite optical fiber having quartz as a cladding with an organic scintillating material core. X-ray detection using these fibers is compared to a collimated cadmium telluride (CdTe) detector over an energy range from 10 to 40 keV. Results show a good correlation between the fiber count rate trend and that of the CdTe detector.

Space optics; Proceedings of the Seminar, Huntsville, Ala., May 22-24, 1979

NASA Technical Reports Server (NTRS)

Wyman, C. L.

1979-01-01

The seminar focused on infrared systems, the space telescope, new design for space astronomy, future earth resources systems, and planetary systems. Papers were presented on infrared astronomy satellite, infrared telescope on Spacelab 2, design alternatives for the Shuttle Infrared Telescope Facility, Spacelab 2 infrared telescope cryogenic system, geometrical theory of diffraction and telescope stray-light analysis, Space Telescope scientific instruments, faint-object spectrograph for the Space Telescope, light scattering from multilayer optics, bidirectional reflectance distribution function measurements of stray light suppression coatings for the Space Telescope, optical fabrication of a 60-in. mirror, interferogram analysis for space optics, nuclear-pumped lasers for space application, geophysical fluid flow experiment, coherent rays for optical astronomy in space, optical system with fiber-optical elements, and Pioneer-Venus solar flux radiometer.

Fabrication of polymer microlenses on single mode optical fibers for light coupling

NASA Astrophysics Data System (ADS)

Zaboub, Monsef; Guessoum, Assia; Demagh, Nacer-Eddine; Guermat, Abdelhak

2016-05-01

In this paper, we present a technique for producing fibers optics micro-collimators composed of polydimethylsiloxane PDMS microlenses of different radii of curvature. The waist and working distance values obtained enable the optimization of optical coupling between optical fibers, fibers and optical sources, and fibers and detectors. The principal is based on the injection of polydimethylsiloxane (PDMS) into a conical micro-cavity chemically etched at the end of optical fibers. A spherical microlens is then formed that is self-centered with respect to the axis of the fiber. Typically, an optimal radius of curvature of 10.08 μm is obtained. This optimized micro-collimator is characterized by a working distance of 19.27 μm and a waist equal to 2.28 μm for an SMF 9/125 μm fiber. The simulation and experimental results reveal an optical coupling efficiency that can reach a value of 99.75%.

THUNDER Piezoelectric Actuators as a Method of Stretch-Tuning an Optical Fiber Grating

NASA Technical Reports Server (NTRS)

Allison, Sidney G.; Fox, Robert L.; Froggatt, Mark E.; Childers, Brooks A.

2000-01-01

A method of stretching optical fiber holds interest for measuring strain in smart structures where the physical displacement may be used to tune optical fiber lasers. A small, light weight, low power tunable fiber laser is ideal for demodulating strain in optical fiber Bragg gratings attached to smart structures such as the re-usable launch vehicle that is being developed by NASA. A method is presented for stretching optical fibers using the THUNDER piezoelectric actuators invented at NASA Langley Research Center. THUNDER actuators use a piezoelectric layer bonded to a metal backing to enable the actuators to produce displacements larger than the unbonded piezoelectric material. The shift in reflected optical wavelength resulting from stretching the fiber Bragg grating is presented. Means of adapting THUNDER actuators for stretching optical fibers is discussed, including ferrules, ferrule clamp blocks, and plastic hinges made with stereo lithography.

Optical fiber sensor having a sol-gel fiber core and a method of making

DOEpatents

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

2006-06-06

A simple, economic wet chemical procedure is described for making sol-gel fibers. The sol-gel fibers made from this process are transparent to ultraviolet, visible and near infrared light. Light can be guided in these fibers by using an organic polymer as a fiber cladding. Alternatively, air can be used as a low refractive index medium. The sol-gel fibers have a micro pore structure which allows molecules to diffuse into the fiber core from the surrounding environment. Chemical and biochemical reagents can be doped into the fiber core. The sol-gel fiber can be used as a transducer for constructing an optical fiber sensor. The optical fiber sensor having an active sol-gel fiber core is more sensitive than conventional evanescent wave absorption based optical fiber sensors.

Study of fiber optics standardization, reliability, and applications

NASA Technical Reports Server (NTRS)

1980-01-01

The use of fiber optics in space applications is investigated. Manufacturers and users detailed the problems they were having with the use or manufacture of fiber optic components. The general consensus of all the companies/agencies interviewed is that fiber optics is a maturing technology and will definitely have a place in future NASA system designs. The use of fiber optics was found to have two main advantages - weight savings and increased bandwidth.

Three-dimensional image formation in fiber-optical second-harmonic-generation microscopy.

PubMed

Gu, Min; Fu, Ling

2006-02-06

Three-dimensional (3-D) image formation in fiber-optical second-harmonic-generation microscopy is revealed to be purely coherent and therefore can be described by a 3-D coherent transfer function (CTF) that exhibits the same spatial frequency passband as that of fiber-optical reflection-mode non-fluorescence microscopy. When the numerical aperture of the fiber is much larger than the angle of convergence of the illumination on the fiber aperture, the performance of fiber-optical second-harmonic-generation microscopy behaves as confocal second-harmonic-generation microscopy. The dependence of axial resolution on fiber coupling parameters shows an improvement of approximately 7%, compared with that in fiber-optical two-photon fluorescence microscopy.

Fabrication of Fiber Optic Grating Apparatus and Method

NASA Technical Reports Server (NTRS)

Wang, Ying (Inventor); Sharma, Anup (Inventor); Grant, Joseph (Inventor)

2005-01-01

An apparatus and method for forming a Bragg grating on an optical fiber using a phase mask to diffract a beam of coherent energy and a lens combined with a pair of mirrors to produce two symmetrical virtual point sources of coherent energy in the plane of the optical fiber. The two virtual light sources produce an interference pattern along the optical fiber. In a further embodiment, the period of the pattern and therefore the Bragg wavelength grating applied to the fiber is varied with the position of the optical fiber relative the lens.

Realization of fiber optic displacement sensors

NASA Astrophysics Data System (ADS)

Guzowski, Bartlomiej; Lakomski, Mateusz

2018-03-01

Fiber optic sensors are very promising because of their inherent advantages such as very small size, hard environment tolerance and impact of electromagnetic fields. In this paper three different types of Intensity Fiber Optic Displacement Sensors (I-FODS) are presented. Three configurations of I-FODS were realized in two varieties. In the first one, the cleaved multimode optical fibers (MMF) were used to collect reflected light, while in the second variety the MMF ended with ball lenses were chosen. To ensure an accurate alignment of optical fibers in the sensor head the MTP C9730 optical fiber ferrules were used. In this paper the influence of distribution of transmitting and detecting optical fibers on sensitivity and linear range of operation of developed I-FODS were investigated. We have shown, that I-FODS with ball lenses receive average 10.5% more reflected power in comparison to the cleaved optical fibers and they increase linearity range of I-FODS by 33%. In this paper, an analysis of each type of the realized sensor and detailed discussion are given.

Microbend fiber-optic temperature sensor

DOEpatents

Weiss, Jonathan D.

1995-01-01

A temperature sensor is made of optical fiber into which quasi-sinusoidal microbends have been permanently introduced. In particular, the present invention includes a graded-index optical fiber directing steady light through a section of the optical fiber containing a plurality of permanent microbends. The microbend section of the optical fiber is contained in a thermally expansive sheath, attached to a thermally expansive structure, or attached to a bimetallic element undergoing temperature changes and being monitored. The microbend section is secured to the thermally expansive sheath which allows the amplitude of the microbends to decrease with temperature. The resultant increase in the optical fiber's transmission thus allows temperature to be measured. The plural microbend section of the optical fiber is secured to the thermally expansive structure only at its ends and the microbends themselves are completely unconstrained laterally by any bonding agent to obtain maximum longitudinal temperature sensitivity. Although the permanent microbends reduce the transmission capabilities of fiber optics, the present invention utilizes this phenomenon as a transduction mechanism which is optimized to measure temperature.

Ultra-weak FBG and its refractive index distribution in the drawing optical fiber.

PubMed

Guo, Huiyong; Liu, Fang; Yuan, Yinquan; Yu, Haihu; Yang, Minghong

2015-02-23

For the online writing of ultra-weak fiber Bragg gratings (FBGs) in the drawing optical fibers, the effects of the intensity profile, pulse fluctuation and pulse width of the excimer laser, as well as the transverse and longitudinal vibrations of the optical fiber have been investigated. Firstly, using Lorentz-Loren equation, Gladstone-Dale mixing rule and continuity equation, we have derived the refractive index (RI) fluctuation along the optical fiber and the RI distribution in the FBG, they are linear with the gradient of longitudinal vibration velocity. Then, we have prepared huge amounts of ultra-weak FBGs in the non-moving optical fiber and obtained their reflection spectra, the measured reflection spectra shows that the intensity profile and pulse fluctuation of the excimer laser, as well as the transverse vibration of the optical fiber are little responsible for the inconsistency of ultra-weak FBGs. Finally, the effect of the longitudinal vibration of the optical fiber on the inconsistency of ultra-weak FBGs has been discussed, and the vibration equations of the drawing optical fiber are given in the appendix.

Distributed fiber-optic laser-ultrasound generation based on ghost-mode of tilted fiber Bragg gratings.

PubMed

Tian, Jiajun; Zhang, Qi; Han, Ming

2013-03-11

Active ultrasonic testing is widely used for medical diagnosis, material characterization and structural health monitoring. Ultrasonic transducer is a key component in active ultrasonic testing. Due to their many advantages such as small size, light weight, and immunity to electromagnetic interference, fiber-optic ultrasonic transducers are particularly attractive for permanent, embedded applications in active ultrasonic testing for structural health monitoring. However, current fiber-optic transducers only allow effective ultrasound generation at a single location of the fiber end. Here we demonstrate a fiber-optic device that can effectively generate ultrasound at multiple, selected locations along a fiber in a controllable manner based on a smart light tapping scheme that only taps out the light of a particular wavelength for laser-ultrasound generation and allow light of longer wavelengths pass by without loss. Such a scheme may also find applications in remote fiber-optic device tuning and quasi-distributed biochemical fiber-optic sensing.

Miniature mechanical transfer optical coupler

DOEpatents

Abel, Philip [Overland Park, KS; Watterson, Carl [Kansas City, MO

2011-02-15

A miniature mechanical transfer (MT) optical coupler ("MMTOC") for optically connecting a first plurality of optical fibers with at least one other plurality of optical fibers. The MMTOC may comprise a beam splitting element, a plurality of collimating lenses, and a plurality of alignment elements. The MMTOC may optically couple a first plurality of fibers disposed in a plurality of ferrules of a first MT connector with a second plurality of fibers disposed in a plurality of ferrules of a second MT connector and a third plurality of fibers disposed in a plurality of ferrules of a third MT connector. The beam splitting element may allow a portion of each beam of light from the first plurality of fibers to pass through to the second plurality of fibers and simultaneously reflect another portion of each beam of light from the first plurality of fibers to the third plurality of fibers.

Microcirculation assessment using an individualized model for diffuse reflectance spectroscopy and conventional laser Doppler flowmetry

NASA Astrophysics Data System (ADS)

Strömberg, Tomas; Karlsson, Hanna; Fredriksson, Ingemar; Nyström, Fredrik H.; Larsson, Marcus

2014-05-01

Microvascular assessment would benefit from co-registration of blood flow and hemoglobin oxygenation dynamics during stimulus response tests. We used a fiber-optic probe for simultaneous recording of white light diffuse reflectance (DRS; 475-850 nm) and laser Doppler flowmetry (LDF; 780 nm) spectra at two source-detector distances (0.4 and 1.2 mm). An inverse Monte Carlo algorithm, based on a multiparameter three-layer adaptive skin model, was used for analyzing DRS data. LDF spectra were conventionally processed for perfusion. The system was evaluated on volar forearm recordings of 33 healthy subjects during a 5-min systolic occlusion protocol. The calibration scheme and the optimal adaptive skin model fitted DRS spectra at both distances within 10%. During occlusion, perfusion decreased within 5 s while oxygenation decreased slowly (mean time constant 61 s dissociation of oxygen from hemoglobin). After occlusion release, perfusion and oxygenation increased within 3 s (inflow of oxygenized blood). The increased perfusion was due to increased blood tissue fraction and speed. The supranormal hemoglobin oxygenation indicates a blood flow in excess of metabolic demands. In conclusion, by integrating DRS and LDF in a fiber-optic probe, a powerful tool for assessment of blood flow and oxygenation in the same microvascular bed has been presented.

Microcirculation assessment using an individualized model for diffuse reflectance spectroscopy and conventional laser Doppler flowmetry.

PubMed

Strömberg, Tomas; Karlsson, Hanna; Fredriksson, Ingemar; Nyström, Fredrik H; Larsson, Marcus

2014-05-01

Microvascular assessment would benefit from co-registration of blood flow and hemoglobin oxygenation dynamics during stimulus response tests. We used a fiber-optic probe for simultaneous recording of white light diffuse reflectance (DRS; 475-850 nm) and laser Doppler flowmetry (LDF; 780 nm) spectra at two source-detector distances (0.4 and 1.2 mm). An inverse Monte Carlo algorithm, based on a multiparameter three-layer adaptive skin model, was used for analyzing DRS data. LDF spectra were conventionally processed for perfusion. The system was evaluated on volar forearm recordings of 33 healthy subjects during a 5-min systolic occlusion protocol. The calibration scheme and the optimal adaptive skin model fitted DRS spectra at both distances within 10%. During occlusion, perfusion decreased within 5 s while oxygenation decreased slowly (mean time constant 61 s; dissociation of oxygen from hemoglobin). After occlusion release, perfusion and oxygenation increased within 3 s (inflow of oxygenized blood). The increased perfusion was due to increased blood tissue fraction and speed. The supranormal hemoglobin oxygenation indicates a blood flow in excess of metabolic demands. In conclusion, by integrating DRS and LDF in a fiber-optic probe, a powerful tool for assessment of blood flow and oxygenation in the same microvascular bed has been presented.

Estimation of coupling efficiency of optical fiber by far-field method

NASA Astrophysics Data System (ADS)

Kataoka, Keiji

2010-09-01

Coupling efficiency to a single-mode optical fiber can be estimated with the field amplitudes at far-field of an incident beam and optical fiber mode. We call it the calculation by far-field method (FFM) in this paper. The coupling efficiency by FFM is formulated including effects of optical aberrations, vignetting of the incident beam, and misalignments of the optical fiber such as defocus, lateral displacements, and angle deviation in arrangement of the fiber. As the results, it is shown the coupling efficiency is proportional to the central intensity of the focused spot, i.e., Strehl intensity of a virtual beam determined by the incident beam and mode of the optical fiber. Using the FFM, a typical optics in which a laser beam is coupled to an optical fiber with a lens of finite numerical aperture (NA) is analyzed for several cases of amplitude distributions of the incident light.

All-optical, thermo-optical path length modulation based on the vanadium-doped fibers.

PubMed

Matjasec, Ziga; Campelj, Stanislav; Donlagic, Denis

2013-05-20

This paper presents an all-fiber, fully-optically controlled, optical-path length modulator based on highly absorbing optical fiber. The modulator utilizes a high-power 980 nm pump diode and a short section of vanadium-co-doped single mode fiber that is heated through absorption and a non-radiative relaxation process. The achievable path length modulation range primarily depends on the pump's power and the convective heat-transfer coefficient of the surrounding gas, while the time response primarily depends on the heated fiber's diameter. An absolute optical length change in excess of 500 µm and a time-constant as short as 11 ms, were demonstrated experimentally. The all-fiber design allows for an electrically-passive and remote operation of the modulator. The presented modulator could find use within various fiber-optics systems that require optical (remote) path length control or modulation.

Experimental stress–strain analysis of tapered silica optical fibers with nanofiber waist

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holleis, S.; Hoinkes, T.; Wuttke, C.

2014-04-21

We experimentally determine tensile force–elongation diagrams of tapered optical fibers with a nanofiber waist. The tapered optical fibers are produced from standard silica optical fibers using a heat and pull process. Both, the force–elongation data and scanning electron microscope images of the rupture points indicate a brittle material. Despite the small waist radii of only a few hundred nanometers, our experimental data can be fully explained by a nonlinear stress–strain model that relies on material properties of macroscopic silica optical fibers. This is an important asset when it comes to designing miniaturized optical elements as one can rely on themore » well-founded material characteristics of standard optical fibers. Based on this understanding, we demonstrate a simple and non-destructive technique that allows us to determine the waist radius of the tapered optical fiber. We find excellent agreement with independent scanning electron microscope measurements of the waist radius.« less

Reduced Gravity Zblan Optical Fiber

NASA Technical Reports Server (NTRS)

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

2000-01-01

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

The effect of irradiation process on the optical fiber coating

NASA Astrophysics Data System (ADS)

Wang, Zeyu; Xiao, Chun; Rong, Liang; Ji, Wei

2018-03-01

Protective fiber coating decides the mechanical strength of an optical fiber as well as its resistance against the influence of environment, especially in some special areas like irradiation atmospheres. According to the experiment in this paper, it was found that the tensile force and peeling force of resistant radiation optical fiber was improved because of the special optical fiber coating.

Controllable photoinduced optical attenuation in a single-mode optical fiber by irradiation of a femtosecond pulse laser.

PubMed

Himei, Yusuke; Qiu, Jianrong; Nakajima, Sotohiro; Sakamoto, Akihiko; Hirao, Kazuyuki

2004-12-01

Novel optical attenuation fibers were fabricated by the irradiation of a focused infrared femtosecond pulsed laser onto the core of a silica glass single-mode optical fiber. Optical attenuation at a wavelength of 1.55 microm proportionally increased with increasing numbers of irradiation points and was controllable under laser irradiation conditions. The single-mode property of the waveguide and the mode-field diameter of the optical fiber were maintained after irradiation of the femtosecond laser. It is suggested that the attenuation results from optical scattering at photoinduced spots formed inside the fiber core.

Robust Mapping of Incoherent Fiber-Optic Bundles

NASA Technical Reports Server (NTRS)

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

2007-01-01

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

Vibrating Optical Fibers to Make Laser Speckle Disappear

NASA Technical Reports Server (NTRS)

McGill, Matthew; Scott, V. Stanley

2005-01-01

In optical systems in which laser illumination is delivered via multimode optical fibers, laser speckle can be rendered incoherent by a simple but highly effective technique. The need to eliminate speckle arises because speckle can make it difficult to observe edges and other sharp features, thereby making it difficult to perform precision alignment of optical components. The basic ideas of the technique is to vibrate the optical fiber(s) to cause shifting of electromagnetic modes within the fiber(s) and consequent shifting of the speckle pattern in the light emerging from the fiber(s). If the frequency of vibration is high enough, a human eye cannot follow the shifting speckle pattern, so that instead of speckle, a human observer sees a smoothed pattern of light corresponding to a mixture of many electromagnetic modes. If necessary, the optical fiber(s) could be vibrated manually. However, in a typical laboratory situation, it would be more practical to attach a vibrating mechanism to the fiber(s) for routine use as part of the fiber-optic illuminator. In experiments, a commercially available small, gentle, quiet, variable- speed vibratory device was used in this way, with the result that the appearance of speckle was eliminated, as expected. Figures 1 and 2 illustrate the difference.

Multi-function diamond film fiber optic probe and measuring system employing same

DOEpatents

Young, J.P.

1998-11-24

A fused fiber optic probe having a protective cover, a fiber optic probe system, and embodiments thereof for conducting electromagnetic spectral measurements are disclosed. The fused fiber optic probe comprises a probe tip having a specific geometrical configuration, an exciting optical fiber and at least one collection optical fiber fused within a housing, preferably silica, with a protective cover disposed over at least a portion of the probe tip. The specific geometrical configurations in which the probe tip can be shaped include a slanted probe tip with an angle greater than 0{degree}, an inverted cone-shaped probe tip, and a lens head. 9 figs.

Fiber optic engine for micro projection display.

PubMed

Arabi, Hesam Edin; An, Sohee; Oh, Kyunghwan

2010-03-01

A novel compact optical engine for a micro projector display is experimentally demonstrated, which is composed of RGB light sources, a tapered 3 x 1 Fiber Optic Color Synthesizer (FOCS) along with a fiberized ball-lens, and a two dimensional micro electromechanical scanning mirror. In the proposed optical engine, we successfully employed an all-fiber beam shaping technique combining optical fiber taper and fiberized ball lens that can render a narrow beam and enhance the resolution of the screened image in the far field. Optical performances of the proposed device assembly are investigated in terms of power loss, collimating strength of the collimator assembly, and color gamut of the output.

In-situ spectrophotometric probe

DOEpatents

Prather, William S.

1992-01-01

A spectrophotometric probe for in situ absorption spectra measurements comprising a first optical fiber carrying light from a remote light source, a second optical fiber carrying light to a remote spectrophotometer, the proximal ends of the first and second optical fibers parallel and coterminal, a planoconvex lens to collimate light from the first optical fiber, a reflecting grid positioned a short distance from the lens to reflect the collimated light back to the lens for focussing on the second optical fiber. The lens is positioned with the convex side toward the optical fibers. A substrate for absorbing analyte or an analyte and reagent mixture may be positioned between the lens and the reflecting grid.

All-optical switching application based on optical nonlinearity of Yb(3+) doped aluminosilicate glass fiber with a long-period fiber gratings pair.

PubMed

Kim, Yune; Kim, Nam; Chung, Youngjoo; Paek, Un-Chul; Han, Won-Taek

2004-02-23

We propose a new fiber-type all-optical switching device based on the optical nonlinearity of Yb(3+) doped fiber and a long-period fiber gratings(LPG) pair. The all-optical ON-OFF switching with the continuous wave laser signal at ~1556nm in the LPG pair including the 25.5cm long Yb(3+) doped fiber was demonstrated up to ~200Hz upon pumping with the modulated square wave pulses at 976nm, where a full optical switching with the ~18dB extinction ratio was obtained at the launched pump power of ~35mW.

Fiber Optic Microswitch For Industrial Use

NASA Astrophysics Data System (ADS)

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

1988-03-01

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

Cryogenic Fiber Optic Assemblies for Spaceflight Environments: Design, Manufacturing, Testing, and Integration

NASA Technical Reports Server (NTRS)

Thomes, W. Joe; Ott, Melanie N.; Chuska, Richard; Switzer, Robert; Onuma, Eleanya; Blair, Diana; Frese, Erich; Matyseck, Marc

2016-01-01

Fiber optic assemblies have been used on spaceflight missions for many years as an enabling technology for routing, transmitting, and detecting optical signals. Due to the overwhelming success of NASA in implementing fiber optic assemblies on spaceflight science-based instruments, system scientists increasingly request fibers that perform in extreme environments while still maintaining very high optical transmission, stability, and reliability. Many new applications require fiber optic assemblies that will operate down to cryogenic temperatures as low as 20 Kelvin. In order for the fiber assemblies to operate with little loss in optical throughput at these extreme temperatures requires a system level approach all the way from how the fiber assembly is manufactured to how it is held, routed, and integrated. The NASA Goddard Code 562 Photonics Group has been designing, manufacturing, testing, and integrating fiber optics for spaceflight and other high reliability applications for nearly 20 years. Design techniques and lessons learned over the years are consistently applied to developing new fiber optic assemblies that meet these demanding environments. System level trades, fiber assembly design methods, manufacturing, testing, and integration will be discussed. Specific recent examples of ground support equipment for the James Webb Space Telescope (JWST); the Ice, Cloud and Land Elevation Satellite-2 (ICESat-2); and others will be included.

US long distance fiber optic networks: Technology, evolution and advanced concepts. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1986-01-01

Over the past two decades, fiber optics has emerged as a highly practical and cost-efficient communications technology. Its competitiveness vis-a-vis other transmission media, especially satellite, has become a critical question. This report studies the likely evolution and application of fiber optic networks in the United States to the end of the century. The outlook for the technology of fiber systems is assessed and forecast, scenarios of the evolution of fiber optic network development are constructed, and costs to provide service are determined and examined parametrically as a function of network size and traffic carried. Volume 1 consists of the Executive Summary. Volume 2 focuses on fiber optic technology and long distance fiber optic networks. Volume 3 develops a traffic and financial model of a nationwide long distance transmission network. Among the study's most important conclusions are: revenue requirements per circuit for LATA-to-LATA fiber optic links are less than one cent per call minute; multiplex equipment, which is likely to be required in any competing system, is the largest contributor to circuit costs; the potential capacity of fiber optic cable is very large and as yet undefined; and fiber optic transmission combined with other network optimization schemes can lead to even lower costs than those identified in this study.

Cryogenic fiber optic assemblies for spaceflight environments: design, manufacturing, testing, and integration

NASA Astrophysics Data System (ADS)

Thomes, W. Joe; Ott, Melanie N.; Chuska, Richard; Switzer, Robert; Onuma, Eleanya; Blair, Diana; Frese, Erich; Matyseck, Marc

2016-09-01

Fiber optic assemblies have been used on spaceflight missions for many years as an enabling technology for routing, transmitting, and detecting optical signals. Due to the overwhelming success of NASA in implementing fiber optic assemblies on spaceflight science-based instruments, system scientists increasingly request fibers that perform in extreme environments while still maintaining very high optical transmission, stability, and reliability. Many new applications require fiber optic assemblies that will operate down to cryogenic temperatures as low as 20 Kelvin. In order for the fiber assemblies to operate with little loss in optical throughput at these extreme temperatures requires a system level approach all the way from how the fiber assembly is manufactured to how it is held, routed, and integrated. The NASA Goddard Code 562 Photonics Group has been designing, manufacturing, testing, and integrating fiber optics for spaceflight and other high reliability applications for nearly 20 years. Design techniques and lessons learned over the years are consistently applied to developing new fiber optic assemblies that meet these demanding environments. System level trades, fiber assembly design methods, manufacturing, testing, and integration will be discussed. Specific recent examples of ground support equipment for the James Webb Space Telescope (JWST); the Ice, Cloud and Land Elevation Satellite-2 (ICESat- 2); and others will be included.

Optically triggered high voltage switch network and method for switching a high voltage

DOEpatents

El-Sharkawi, Mohamed A.; Andexler, George; Silberkleit, Lee I.

1993-01-19

An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits. The trigger circuits are connected to one of the distribution lines through a trigger capacitor (340). In each switch driver, the light signals activate a phototransistor (300) so that an electrical current flows from one of the energy reservoir capacitors through a pulse transformer (306) in the trigger circuit, producing gate signals that turn on the pair of serially connected solid state switches (350).

Fiber-optic polarization diversity detection for rotary probe optical coherence tomography.

PubMed

Lee, Anthony M D; Pahlevaninezhad, Hamid; Yang, Victor X D; Lam, Stephen; MacAulay, Calum; Lane, Pierre

2014-06-15

We report a polarization diversity detection scheme for optical coherence tomography with a new, custom, miniaturized fiber coupler with single mode (SM) fiber inputs and polarization maintaining (PM) fiber outputs. The SM fiber inputs obviate matching the optical lengths of the X and Y OCT polarization channels prior to interference and the PM fiber outputs ensure defined X and Y axes after interference. Advantages for this scheme include easier alignment, lower cost, and easier miniaturization compared to designs with free-space bulk optical components. We demonstrate the utility of the detection system to mitigate the effects of rapidly changing polarization states when imaging with rotating fiber optic probes in Intralipid suspension and during in vivo imaging of human airways.

Video flowmeter

DOEpatents

Lord, David E.; Carter, Gary W.; Petrini, Richard R.

1983-01-01

A video flowmeter is described that is capable of specifying flow nature and pattern and, at the same time, the quantitative value of the rate of volumetric flow. An image of a determinable volumetric region within a fluid (10) containing entrained particles (12) is formed and positioned by a rod optic lens assembly (31) on the raster area of a low-light level television camera (20). The particles (12) are illuminated by light transmitted through a bundle of glass fibers (32) surrounding the rod optic lens assembly (31). Only particle images having speeds on the raster area below the raster line scanning speed may be used to form a video picture which is displayed on a video screen (40). The flowmeter is calibrated so that the locus of positions of origin of the video picture gives a determination of the volumetric flow rate of the fluid (10).

Fusion splicing: a novel approach to fiber connections for the Dark Energy Spectroscopic Instrument

NASA Astrophysics Data System (ADS)

Fagrelius, Parker; Poppett, Claire; Edelstein, Jerry

2016-08-01

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the universe using the Baryon Acoustic Oscillation (BAO) technique and the growth of structure using redshift-space distortions (RSD). The spectra of 40 million galaxies over 14,000 square degrees will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber optic positioners. The fibers will run 50 meters from the focal plane to the coudé room where they feed ten broadband spectrographs. The focal plane assembly will be integrated separately from the spectrograph slits and long fiber cables in order to ease integration flow, and the two subsystems will be connected before final integration on the telescope. In order to retain maximum throughput and minimize the focal ratio degradation (FRD) when connecting the fiber system, we are employing fusion splicing as opposed to mechanical connectorization. For the best splice performance, the optical fibers are stripped of their polyimide coating, precision cleaved, and then fused with a heating filament. We report results from the splicing process, measuring a collimated FRD increase of less than 0.5 degrees for a f/3.9 input beam compared to >1 degree increase for mechanical connectors. We also show that the near field performance is minimally degraded after splicing. These results represent the first of their kind for a fiber-fed astronomical instrument.

A multicore optical fiber for distributed sensing

NASA Astrophysics Data System (ADS)

Sun, Xiaoguang; Li, Jie; Burgess, David T.; Hines, Mike; Zhu, Beyuan

2014-06-01

With advancements in optical fiber technology, the incorporation of multiple sensing functionalities within a single fiber structure opens the possibility to deploy dielectric, fully distributed, long-length optical sensors in an extremely small cross section. To illustrate the concept, we designed and manufactured a multicore optical fiber with three graded-index (GI) multimode (MM) cores and one single mode (SM) core. The fiber was coated with both a silicone primary layer and an ETFE buffer for high temperature applications. The fiber properties such as geometry, crosstalk and attenuation are described. A method for coupling the signal from the individual cores into separate optical fibers is also presented.

Model of an axially strained weakly guiding optical fiber modal pattern

NASA Technical Reports Server (NTRS)

Egalon, Claudio O.; Rogowski, Robert S.

1992-01-01

Axial strain can be determined by monitoring the modal pattern variation of an optical fiber. The results of a numerical model developed to calculate the modal pattern variation at the end of a weakly guiding optical fiber under axial strain is presented. Whenever an optical fiber is under stress, the optical path length, the index of refraction, and the propagation constants of each fiber mode change. In consequence, the modal phase term for the fields and the fiber output pattern are also modified. For multimode fibers, very complicated patterns result. The predicted patterns are presented, and an expression for the phase variation with strain is derived.

Two-way wireless-over-fibre and FSO-over-fibre communication systems with an optical carrier transmission

NASA Astrophysics Data System (ADS)

Huang, Xu-Hong; Lu, Hai-Han; Donati, Silvano; Li, Chung-Yi; Wang, Yun-Chieh; Jheng, Yu-Bo; Chang, Jen-Chieh

2018-07-01

Two-way wireless-over-fiber and free-space optical (FSO)-over-fiber communication systems, with an optical carrier transmission for a hybrid 10 Gbps baseband data stream, are proposed and practically demonstrated. 10 Gbps/50 GHz and 10 Gbps/100 GHz millimeter-wave data signal transmissions are also proposed and practically demonstrated. An optical carrier with a 10 Gbps baseband data stream is delivered via a 50 km single-mode fiber transportation to effectively lower dispersion-induced limitation due to fiber links and distortion produced by beating among multiple optical sidebands. To our understanding, this experiment is foremost in employing an optical carrier transmission approach to a two-way wireless-over-fiber and FSO-over-fiber communication system to suppress fiber dispersion and distortion effectively. Bit error rate performs well for downlink and uplink deliveries via a 50 km single-mode fiber transportation with a 100 m FSO link/5 m RF wireless delivery. The offered two-way wireless-over-fiber and FSO-over-fiber communication system with an optical carrier transmission is a promising option. It should be interesting for signifying the progress in the integration of long-haul fiber-based trunks and short-range RF/optical wireless link-based branches.

Sealed fiber-optic bundle feedthrough

DOEpatents

Tanner, Carol E.

2002-01-01

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.

On the mechanical coupling of a fiber optic cable used for distributed acoustic/vibration sensing applications—a theoretical consideration

NASA Astrophysics Data System (ADS)

Reinsch, Thomas; Thurley, Tom; Jousset, Philippe

2017-12-01

In recent years, fiber optic cables are increasingly used for the acquisition of dynamic strain changes for seismic surveys. When considering seismic amplitudes, one of the first questions arising is the mechanical coupling between optical fiber and the surrounding medium. Here we analyse the interaction of ground movement with a typical telecom-grade fiber optic cable from an existing telecommunication network deployed in a sand filled trench at the surface. Within the cable, the optical fiber is embedded in a gel-filled plastic tube. We apply Hooke’s law to calculate the stress needed to strain the optical fiber throughout the cable structure. In case the stress magnitude at the cable-sand interface as well as the gel-optical fiber interface is below the yield strength of the respective material, sand and gel, it can be regarded as an elastic medium. Hence, a multilayer radial symmetric model can be used to calculate the coupling of the optical fiber with the surrounding medium. We show that the transfer function has a -3 dB lower cut-off wavelength of about 22 m. The magnitude response of this telecom-grade fiber optic cable is therefore almost perfect at typical low frequency seismic waves. The approach presented here can be applied to various cable designs to estimate the strain transfer between ground movement and an optical fiber.

Nondestructive distributed measurement of supercontinuum generation along highly nonlinear optical fibers.

PubMed

Hontinfinde, Régis; Coulibaly, Saliya; Megret, Patrice; Taki, Majid; Wuilpart, Marc

2017-05-01

Supercontinuum generation (SCG) in optical fibers arises from the spectral broadening of an intense light, which results from the interplay of both linear and nonlinear optical effects. In this Letter, a nondestructive optical time domain reflectometry method is proposed for the first time, to the best of our knowledge, to measure the spatial (longitudinal) evolution of the SC induced along an optical fiber. The method was experimentally tested on highly nonlinear fibers. The experimental results are in a good agreement with the optical spectra measured at the fiber outputs.

Fiber-optic apparatus and method for measurement of luminescence and raman scattering

DOEpatents

Myrick, Michael L.; Angel, Stanley M.

1993-01-01

A dual fiber forward scattering optrode for Raman spectroscopy with the remote ends of the fibers in opposed, spaced relationship to each other to form a analyte sampling space therebetween and the method of measuring Raman spectra utilizing same. One optical fiber is for sending an exciting signal to the remote sampling space and, at its remote end, has a collimating microlens and an optical filter for filtering out background emissions generated in the fiber. The other optical fiber is for collecting the Raman scattering signal at the remote sampling space and, at its remote end, has a collimating microlens and an optical filter to prevent the exciting signal from the exciting fiber from entering the collection fiber and to thereby prevent the generation of background emissions in the collecting fiber.

Splicing Efficiently Couples Optical Fibers

NASA Technical Reports Server (NTRS)

Lutes, G. F.

1985-01-01

Method of splicing single-mode optical fibers results in very low transmission losses through joined fiber ends. Coupling losses between joined optical-fiber ends only 0.1 dB. Method needs no special operator training.

Multi-Stress Monitoring System with Fiber-Optic Mandrels and Fiber Bragg Grating Sensors in a Sagnac Loop

PubMed Central

Kim, Hyunjin; Sampath, Umesh; Song, Minho

2015-01-01

Fiber Bragg grating sensors are placed in a fiber-optic Sagnac loop to combine the grating temperature sensors and the fiber-optic mandrel acoustic emission sensors in single optical circuit. A wavelength-scanning fiber-optic laser is used as a common light source for both sensors. A fiber-optic attenuator is placed at a specific position in the Sagnac loop in order to separate buried Bragg wavelengths from the Sagnac interferometer output. The Bragg wavelength shifts are measured with scanning band-pass filter demodulation and the mandrel output is analyzed by applying a fast Fourier transform to the interference signal. This hybrid-scheme could greatly reduce the size and the complexity of optical circuitry and signal processing unit, making it suitable for low cost multi-stress monitoring of large scale power systems. PMID:26230700

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

NASA Technical Reports Server (NTRS)

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

1992-01-01

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.

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

NASA Technical Reports Server (NTRS)

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

1993-01-01

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

Dynamics of Nonlinear Excitation of the High-Order Mode in a Single-Mode Step-Index Optical Fiber

NASA Astrophysics Data System (ADS)

Burdin, V.; Bourdine, A.

2018-04-01

This work is concerned with approximate model of higher-order mode nonlinear excitation in a singlemode silica optical fiber. We present some results of simulation for step-index optical fiber under femtosecond optical pulse launching, which confirm ability of relatively stable higher-order mode excitation in such singlemode optical fiber over sufficiently narrow range of launched optical power variation.

Chemistry Research of Optical Fibers.

DTIC Science & Technology

1982-09-27

BROADENING IN OPTICAL FIBERS Herbert B. Rosenstock* Naval Research Laboratory Washington, DC 20375 ABSTRACT A light pulse transmitted through a fiber...Marcatili, Marcuse , and Personick, "Dispersion Properties of Fibers" (Ch. 4 in "Optical Fiber Telecommunications," S. E. Miller and A. C. Chynoweth, eds

Analysis of creating an innovative micro-lens made of polydimethylsiloxane polymer on the end of the optical fibers

NASA Astrophysics Data System (ADS)

Zboril, O.; Cubik, J.; Nedoma, J.; Fajkus, M.; Novak, M.; Jargus, J.; Stratil, T.; Vasinek, V.

2017-10-01

The article describes a method for fabrication of polymer optical micro-lenses using polydimethylsiloxane (PDMS) at the end of optical fibers. PDMS is an optically clear substance having a refractive index very similar to the optical fibers. Therefore it is an interesting material for optical purposes. PDMS is characterized by resistance to electromagnetic interference (EMI), enabling the use in electromagnetically noisy environments. These lenses could be used for example for the security applications. For the manufacture of the micro-lenses is used Sylgard silicone elastomer 184. When applied to the end of conventional optical fiber is cured by treatment at 100 °C +/- 5 °C. Authors performed a series of experimental measurements. The optical characteristics of the treated fibers compared with conventional fibers without micro-lenses. The fibers provided with optical lenses made of PDMS may be used for security applications, in the visible light communication (VLC) or as a microprobe.

Opto-acoustic recanilization delivery system

DOEpatents

Visuri, Steven R.; Da Silva, Luiz B.; Celliers, Peter M.; London, Richard A.; Benett, William; Broughton, Kathryn; Esch, Victor

2002-01-01

Fiber delivered laser pulses emulsify thrombus by mechanical stresses that include a combination of pressure, tension and shear stress. Laser radiation is delivered to the locality of a thrombus and the radiation is absorbed by blood, blood dot, or other present materials. The combination of a leading pressure wave and subsequent vapor bubble cause efficient, emulsification of thrombus. Operating the laser in a low average power mode alleviates potential thermal complications. The laser is operated in a high repetition rate mode to take advantage of ultrasound frequency effects of thrombus dissolution as well as to decrease the total procedure time. Specific parameter ranges for operation are described. The device includes optical fibers surrounding a lumen intended for flow of a cooling agent. The fibers may be arranged concentrically around the lumen to deliver radiation and heat over as large an area as possible. An alternative design approach incorporates the optical fibers into the wall of the guiding catheter and utilizes the catheter lumen as the cooling channel. An eccentric tip enables rotation of the device to address all parts of the vasculature. The eccentricity can be provided via a variety of means: spring dip, balloon, protrusion, etc.

Aerogel-clad optical fiber

DOEpatents

Sprehn, G.A.; Hrubesh, L.W.; Poco, J.F.; Sandler, P.H.

1997-11-04

An optical fiber is surrounded by an aerogel cladding. For a low density aerogel, the index of refraction of the aerogel is close to that of air, which provides a high numerical aperture to the optical fiber. Due to the high numerical aperture, the aerogel clad optical fiber has improved light collection efficiency. 4 figs.

Aerogel-clad optical fiber

DOEpatents

Sprehn, Gregory A.; Hrubesh, Lawrence W.; Poco, John F.; Sandler, Pamela H.

1997-01-01

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

The Over-Selling of Fiber Optics? Cable Planning for Educational Technology.

ERIC Educational Resources Information Center

Kovacs, Robert E.

1993-01-01

Describes fiber optic cables and coaxial cables and considers when each would be appropriate for educational technology. Single mode versus multimode fiber optics are explained, advantages and disadvantages of each type of cable are discussed, and guidelines for choosing fiber optic cables and coaxial cables are offered. (LRW)

Fiber Optics and Library Technology.

ERIC Educational Resources Information Center

Koenig, Michael

1984-01-01

This article examines fiber optic technology, explains some of the key terminology, and speculates about the way fiber optics will change our world. Applications of fiber optics to library systems in three major areas--linkage of a number of mainframe computers, local area networks, and main trunk communications--are highlighted. (EJS)

VKI Activities in Support of AFOSR Basic Research Interests: Steady State Pyrolysis and Ablation Investigation

DTIC Science & Technology

2008-03-31

flux with and without chocking flows above 0.04 g/ s, the heat flux becomes more constant, only slightly de- creasing with increased transpiration...the flowfield species and the injected species. For air, the initial species are N2 and 02. As the flow passes through the shock wave surrounding the...fiber. The captured light is then sent to an Ocean Optics HR4000CG-UV-NIR spectrometer for dispersion and recording of the spectra. The main

KSC-02pd1129

NASA Image and Video Library

2002-07-10

KENNEDY SPACE CENTER, FLA. -- With the engines removed from Endeavour, the inside of Endeavour is exposed. At left center, Scott Minnick, with United Space Alliance, operates a fiber-optic camera inside the flow line. Other USA team members, right, watching the progress on a screen in front, are Gerry Kathka (with controls), Mike Fore and Peggy Ritchie. The inspection is the result of small cracks being discovered on the LH2 Main Propulsion System (MPS) flow liners in other orbiters. Endeavour is next scheduled to fly on mission STS-113.

Micro-Optical Distributed Sensors for Aero Propulsion Applications

NASA Astrophysics Data System (ADS)

Arnold, S.; Otugen, V.

2003-01-01

The objective of this research is to develop micro-opto-mechanical system (MOMS)-based sensors for time- and space-resolved measurements of flow properties in aerodynamics applications. The measurement technique we propose uses optical resonances in dielectric micro-spheres that can be excited by radiation tunneling from optical fibers. It exploits the tunneling-induced and morphology-dependent shifts in the resonant frequencies. The shift in the resonant frequency is dependent on the size, shape, and index of refraction of the micro-sphere. A physical change in the environment surrounding a micro-bead can change one or more of these properties of the sphere thereby causing a shift in frequency of resonance. The change of the resonance frequency can be detected with high resolution by scanning a frequency-tunable laser that is coupled into the fiber and observing the transmission spectrum at the output of the fiber. It is expected that, in the future, the measurement concept will lead to a system of distributed micro-sensors providing spatial data resolved in time and space. The present project focuses on the development and demonstration of temperature sensors using the morphology-dependent optical resonances although in the latter part of the work, we will also develop a pressure sensor. During the period covered in this report, the optical and electronic equipment necessary for the experimental work was assembled and the experimental setup was designed for the single sensor temperature measurements. Software was developed for real-time tracking of the optical resonance shifts. Some preliminary experiments were also carried out to detect temperature using a single bead in a water bath.

Micro-optical Distributed Sensors for Aero Propulsion Applications

NASA Technical Reports Server (NTRS)

Arnold, S.; Otugen, V.; Seasholtz, Richard G. (Technical Monitor)

2003-01-01

The objective of this research is to develop micro-opto-mechanical system (MOMS)-based sensors for time- and space-resolved measurements of flow properties in aerodynamics applications. The measurement technique we propose uses optical resonances in dielectric micro-spheres that can be excited by radiation tunneling from optical fibers. It exploits the tunneling-induced and morphology-dependent shifts in the resonant frequencies. The shift in the resonant frequency is dependent on the size, shape, and index of refraction of the micro-sphere. A physical change in the environment surrounding a micro-bead can change one or more of these properties of the sphere thereby causing a shift in frequency of resonance. The change of the resonance frequency can be detected with high resolution by scanning a frequency-tunable laser that is coupled into the fiber and observing the transmission spectrum at the output of the fiber. It is expected that, in the future, the measurement concept will lead to a system of distributed micro-sensors providing spatial data resolved in time and space. The present project focuses on the development and demonstration of temperature sensors using the morphology-dependent optical resonances although in the latter part of the work, we will also develop a pressure sensor. During the period covered in this report, the optical and electronic equipment necessary for the experimental work was assembled and the experimental setup was designed for the single sensor temperature measurements. Software was developed for real-time tracking of the optical resonance shifts. Some preliminary experiments were also carried out to detect temperature using a single bead in a water bath.

Making Optical-Fiber Chemical Detectors More Sensitive

NASA Technical Reports Server (NTRS)

Rogowski, Robert S.; Egalon, Claudio O.

1993-01-01

Calculations based on exact theory of optical fiber shown how to increase optical efficiency and sensitivity of active-cladding step-index-profile optical-fiber fluorosensor using evanescent wave coupling. Optical-fiber fluorosensor contains molecules fluorescing when illuminated by suitable light in presence of analyte. Fluorescence coupled into and launched along core by evanescent-wave interaction. Efficiency increases with difference in refractive indices.

All-fiber hybrid photon-plasmon circuits: integrating nanowire plasmonics with fiber optics.

PubMed

Li, Xiyuan; Li, Wei; Guo, Xin; Lou, Jingyi; Tong, Limin

2013-07-01

We demonstrate all-fiber hybrid photon-plasmon circuits by integrating Ag nanowires with optical fibers. Relying on near-field coupling, we realize a photon-to-plasmon conversion efficiency up to 92% in a fiber-based nanowire plasmonic probe. Around optical communication band, we assemble an all-fiber resonator and a Mach-Zehnder interferometer (MZI) with Q-factor of 6 × 10(6) and extinction ratio up to 30 dB, respectively. Using the MZI, we demonstrate fiber-compatible plasmonic sensing with high sensitivity and low optical power.

Optical fiber design with orbital angular momentum light purity higher than 99.9.

PubMed

Zhang, Zhishen; Gan, Jiulin; Heng, Xiaobo; Wu, Yuqing; Li, Qingyu; Qian, Qi; Chen, Dongdan; Yang, Zhongmin

2015-11-16

The purity of the synthesized orbital-angular-momentum (OAM) light in the fiber is inversely proportional to channel crosstalk level in the OAM optical fiber communication system. Here the relationship between the fiber structure and the purity is firstly demonstrated in theory. The graded-index optical fiber is proposed and designed for the OAM light propagation with the purity higher than 99.9%. 16 fiber modes (10 OAM modes) have been supported by a specific designed graded-index optical fiber with dispersion less than 35 ps/(km∙nm). Such fiber design has suppressed the intrinsic crosstalk to be lower than -30 dB, and can be potentially used for the long distance OAM optical communication system.

Use of heat as a groundwater tracer in fractured rock hydrology

NASA Astrophysics Data System (ADS)

Bour, Olivier; Le Borgne, Tanguy; Klepikova, Maria V.; Read, Tom; Selker, John S.; Bense, Victor F.; Le Lay, Hugo; Hochreutener, Rebecca; Lavenant, Nicolas

2015-04-01

Crystalline rocks aquifers are often difficult to characterize since flows are mainly localized in few fractures. In particular, the geometry and the connections of the main flow paths are often only partly constrained with classical hydraulic tests. Here, we show through few examples how heat can be used to characterize groundwater flows in fractured rocks at the borehole, inter-borehole and watershed scale. Estimating flows from temperature measurements requires heat advection to be the dominant process of heat transport, but this condition is generally met in fractured rock at least within the few structures where flow is highly channelized. At the borehole scale, groundwater temperature variations with depth can be used to locate permeable fractures and to estimates borehole flows. Measurements can be done with classical multi-parameters probes, but also with recent technologies such as Fiber Optic Distributed Temperature Sensing (FO-DTS) which allows to measure temperature over long distances with an excellent spatial and temporal resolution. In addition, we show how a distributed borehole flowmeter can be achieved using an armored fiber-optic cable and measuring the difference in temperature between a heated and unheated cable that is a function of the fluid velocity. At the inter-borehole scale, temperature changes during cross-borehole hydraulic tests allow to identify the connections and the hydraulic properties of the main flow paths between boreholes. At the aquifer scale, groundwater temperature may be monitored to record temperature changes and estimate groundwater origin. In the example chosen, the main water supply comes from a depth of at least 300 meters through relatively deep groundwater circulation within a major permeable fault zone. The influence of groundwater extraction is clearly identified through groundwater temperature monitoring. These examples illustrate the advantages and limitations of using heat and groundwater temperature measurements for fractured rock hydrology.

Fiber-Optic Strain Sensors With Linear Characteristics

NASA Technical Reports Server (NTRS)

Egalon, Claudio O.; Rogowski, Robert S.

1993-01-01

Fiber-optic modal domain strain sensors having linear characteristics over wide range of strains proposed. Conceived in effort to improve older fiber-optic strain sensors. Linearity obtained by appropriate choice of design parameters. Pattern of light and dark areas at output end of optical fiber produced by interference between electromagnetic modes in which laser beam propagates in fiber. Photodetector monitors intensity at one point in pattern.

High density array fabrication and readout method for a fiber optic biosensor

DOEpatents

Pinkel, Daniel; Gray, Joe

1997-01-01

The invention relates to the fabrication and use of biosensors comprising a plurality of optical fibers each fiber having attached to its "sensor end" biological "binding partners" (molecules that specifically bind other molecules to form a binding complex such as antibody-antigen, lectin-carbohydrate, nucleic acid-nucleic acid, biotin-avidin, etc.). The biosensor preferably bears two or more different species of biological binding partner. The sensor is fabricated by providing a plurality of groups of optical fibers. Each group is treated as a batch to attach a different species of biological binding partner to the sensor ends of the fibers comprising that bundle. Each fiber, or group of fibers within a bundle, may be uniquely identified so that the fibers, or group of fibers, when later combined in an array of different fibers, can be discretely addressed. Fibers or groups of fibers are then selected and discretely separated from different bundles. The discretely separated fibers are then combined at their sensor ends to produce a high density sensor array of fibers capable of assaying simultaneously the binding of components of a test sample to the various binding partners on the different fibers of the sensor array. The transmission ends of the optical fibers are then discretely addressed to detectors--such as a multiplicity of optical sensors. An optical signal, produced by binding of the binding partner to its substrate to form a binding complex, is conducted through the optical fiber or group of fibers to a detector for each discrete test. By examining the addressed transmission ends of fibers, or groups of fibers, the addressed transmission ends can transmit unique patterns assisting in rapid sample identification by the sensor.

High density array fabrication and readout method for a fiber optic biosensor

DOEpatents

Pinkel, Daniel; Gray, Joe; Albertson, Donna G.

2000-01-01

The invention relates to the fabrication and use of biosensors comprising a plurality of optical fibers each fiber having attached to its "sensor end" biological "binding partners" (molecules that specifically bind other molecules to form a binding complex such as antibody-antigen, lectin-carbohydrate, nucleic acid-nucleic acid, biotin-avidin, etc.). The biosensor preferably bears two or more different species of biological binding partner. The sensor is fabricated by providing a plurality of groups of optical fibers. Each group is treated as a batch to attach a different species of biological binding partner to the sensor ends of the fibers comprising that bundle. Each fiber, or group of fibers within a bundle, may be uniquely identified so that the fibers, or group of fibers, when later combined in an array of different fibers, can be discretely addressed. Fibers or groups of fibers are then selected and discretely separated from different bundles. The discretely separated fibers are then combined at their sensor ends to produce a high density sensor array of fibers capable of assaying simultaneously the binding of components of a test sample to the various binding partners on the different fibers of the sensor array. The transmission ends of the optical fibers are then discretely addressed to detectors--such as a multiplicity of optical sensors. An optical signal, produced by binding of the binding partner to its substrate to form a binding complex, is conducted through the optical fiber or group of fibers to a detector for each discrete test. By examining the addressed transmission ends of fibers, or groups of fibers, the addressed transmission ends can transmit unique patterns assisting in rapid sample identification by the sensor.

High density array fabrication and readout method for a fiber optic biosensor

DOEpatents

Pinkel, Daniel; Gray, Joe; Albertson, Donna G.

2002-01-01

The invention relates to the fabrication and use of biosensors comprising a plurality of optical fibers each fiber having attached to its "sensor end" biological "binding partners" (molecules that specifically bind other molecules to form a binding complex such as antibody-antigen, lectin-carbohydrate, nucleic acid-nucleic acid, biotin-avidin, etc.). The biosensor preferably bears two or more different species of biological binding partner. The sensor is fabricated by providing a plurality of groups of optical fibers. Each group is treated as a batch to attach a different species of biological binding partner to the sensor ends of the fibers comprising that bundle. Each fiber, or group of fibers within a bundle, may be uniquely identified so that the fibers, or group of fibers, when later combined in an array of different fibers, can be discretely addressed. Fibers or groups of fibers are then selected and discretely separated from different bundles. The discretely separated fibers are then combined at their sensor ends to produce a high density sensor array of fibers capable of assaying simultaneously the binding of components of a test sample to the various binding partners on the different fibers of the sensor array. The transmission ends of the optical fibers are then discretely addressed to detectors--such as a multiplicity of optical sensors. An optical signal, produced by binding of the binding partner to its substrate to form a binding complex, is conducted through the optical fiber or group of fibers to a detector for each discrete test. By examining the addressed transmission ends of fibers, or groups of fibers, the addressed transmission ends can transmit unique patterns assisting in rapid sample identification by the sensor.

High density array fabrication and readout method for a fiber optic biosensor

DOEpatents

Pinkel, D.; Gray, J.

1997-11-25

The invention relates to the fabrication and use of biosensors comprising a plurality of optical fibers each fiber having attached to its ``sensor end`` biological ``binding partners`` (molecules that specifically bind other molecules to form a binding complex such as antibody-antigen, lectin-carbohydrate, nucleic acid-nucleic acid, biotin-avidin, etc.). The biosensor preferably bears two or more different species of biological binding partner. The sensor is fabricated by providing a plurality of groups of optical fibers. Each group is treated as a batch to attach a different species of biological binding partner to the sensor ends of the fibers comprising that bundle. Each fiber, or group of fibers within a bundle, may be uniquely identified so that the fibers, or group of fibers, when later combined in an array of different fibers, can be discretely addressed. Fibers or groups of fibers are then selected and discretely separated from different bundles. The discretely separated fibers are then combined at their sensor ends to produce a high density sensor array of fibers capable of assaying simultaneously the binding of components of a test sample to the various binding partners on the different fibers of the sensor array. The transmission ends of the optical fibers are then discretely addressed to detectors--such as a multiplicity of optical sensors. An optical signal, produced by binding of the binding partner to its substrate to form a binding complex, is conducted through the optical fiber or group of fibers to a detector for each discrete test. By examining the addressed transmission ends of fibers, or groups of fibers, the addressed transmission ends can transmit unique patterns assisting in rapid sample identification by the sensor. 9 figs.

Observation of orbital angular momentum transfer between acoustic and optical vortices in optical fiber.

PubMed

Dashti, Pedram Z; Alhassen, Fares; Lee, Henry P

2006-02-03

Acousto-optic interaction in optical fiber is examined from the perspective of copropagating optical and acoustic vortex modes. Calculation of the acousto-optic coupling coefficient between different optical modes leads to independent conservation of spin and orbital angular momentum of the interacting photons and phonons. We show that the orbital angular momentum of the acoustic vortex can be transferred to a circularly polarized fundamental optical mode to form a stable optical vortex in the fiber carrying orbital angular momentum. The technique provides a useful way of generating stable optical vortices in the fiber medium.

Low loss hollow-core waveguide on a silicon substrate

NASA Astrophysics Data System (ADS)

Yang, Weijian; Ferrara, James; Grutter, Karen; Yeh, Anthony; Chase, Chris; Yue, Yang; Willner, Alan E.; Wu, Ming C.; Chang-Hasnain, Connie J.

2012-07-01

Optical-fiber-based, hollow-core waveguides (HCWs) have opened up many new applications in laser surgery, gas sensors, and non-linear optics. Chip-scale HCWs are desirable because they are compact, light-weight and can be integrated with other devices into systems-on-a-chip. However, their progress has been hindered by the lack of a low loss waveguide architecture. Here, a completely new waveguiding concept is demonstrated using two planar, parallel, silicon-on-insulator wafers with high-contrast subwavelength gratings to reflect light in-between. We report a record low optical loss of 0.37 dB/cm for a 9-μm waveguide, mode-matched to a single mode fiber. Two-dimensional light confinement is experimentally realized without sidewalls in the HCWs, which is promising for ultrafast sensing response with nearly instantaneous flow of gases or fluids. This unique waveguide geometry establishes an entirely new scheme for low-cost chip-scale sensor arrays and lab-on-a-chip applications.

Oxygenation level and hemoglobin concentration in experimental tumor estimated by diffuse optical spectroscopy

NASA Astrophysics Data System (ADS)

Orlova, A. G.; Kirillin, M. Yu.; Volovetsky, A. B.; Shilyagina, N. Yu.; Sergeeva, E. A.; Golubiatnikov, G. Yu.; Turchin, I. V.

2017-07-01

Using diffuse optical spectroscopy the level of oxygenation and hemoglobin concentration in experimental tumor in comparison with normal muscle tissue of mice have been studied. Subcutaneously growing SKBR-3 was used as a tumor model. Continuous wave fiber probe diffuse optical spectroscopy system was employed. Optical properties extraction approach was based on diffusion approximation. Decreased blood oxygen saturation level and increased total hemoglobin content were demonstrated in the neoplasm. The main reason of such differences between tumor and norm was significant elevation of deoxyhemoglobin concentration in SKBR-3. The method can be useful for diagnosis of tumors as well as for study of blood flow parameters of tumor models with different angiogenic properties.

Space Flight Applications of Optical Fiber; 30 Years of Space Flight Success

NASA Technical Reports Server (NTRS)

Ott, Melanie N.

2010-01-01

For over thirty years NASA has had success with space flight missions that utilize optical fiber component technology. One of the early environmental characterization experiments that included optical fiber was launched as the Long Duration Exposure Facility in 1978. Since then, multiple missions have launched with optical fiber components that functioned as expected, without failure throughout the mission life. The use of optical fiber in NASA space flight communications links and exploration and science instrumentation is reviewed.

Optical fiber-based biosensors.

PubMed

Monk, David J; Walt, David R

2004-08-01

This review outlines optical fiber-based biosensor research from January 2001 through September 2003 and was written to complement the previous review in this journal by Marazuela and Moreno-Bondi. Optical fiber-based biosensors combine the use of a biological recognition element with an optical fiber or optical fiber bundle. They are classified by the nature of the biological recognition element used for sensing: enzyme, antibody/antigen (immunoassay), nucleic acid, whole cell, and biomimetic, and may be used for a variety of analytes ranging from metals and chemicals to physiological materials.

Propagating modes in gain-guided optical fibers.

PubMed

Siegman, A E

2003-08-01

Optical fibers in which gain-guiding effects are significant or even dominant compared with conventional index guiding may become of practical interest for future high-power single-mode fiber lasers. I derive the propagation characteristics of symmetrical slab waveguides and cylindrical optical fibers having arbitrary amounts of mixed gain and index guiding, assuming a single uniform transverse profile for both the gain and the refractive-index steps. Optical fibers of this type are best characterized by using a complex-valued v-squared parameter in place of the real-valued v parameter commonly used to describe conventional index-guided optical fibers.

A forty-year history of fiber optic smart structures

NASA Astrophysics Data System (ADS)

Udd, Eric; Scheel, Ingrid U.

2017-04-01

In 1977 McDonnell Douglas Astronautics Company began a project on using fiber optic sensors to support the Delta Rocket program. This resulted in a series of fiber sensors to support the measurement of rotation, acoustics, vibration, strain, and temperature for a variety of applications and early work on fiber optic smart structures. The work on fiber optic smart structures transitioned in part to Blue Road Research in 1993 and continued in 2006 to the present at Columbia Gorge Research. This paper summarizes some of the efforts made by these companies to implement fiber optic smart structures over this forty year period.

Optical Fiber Networks for Remote Fiber Optic Sensors

PubMed Central

Fernandez-Vallejo, Montserrat; Lopez-Amo, Manuel

2012-01-01

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

Vibration Performance Comparison Study on Current Fiber Optic Connector Technologies

NASA Technical Reports Server (NTRS)

Ott, Melanie N.; Thomes Jr., William J.; LaRocca, Frank V.; Switzer, Robert C.; Chuska, Rick F.; Macmurphy, Shawn L.

2008-01-01

Fiber optic cables are increasingly being used in harsh environments where they are subjected to vibration. Understanding the degradation in performance under these conditions is essential for integration of the fibers into the given application. System constraints oftentimes require fiber optic connectors so subsystems can be removed or assembled as needed. In the present work, various types of fiber optic connectors were monitored in-situ during vibration testing to examine the transient change in optical transmission and the steady-state variation following the event. Inspection of the fiber endfaces and connectors was performed at chosen intervals throughout the testing.

Micro-optical fiber probe for use in an intravascular Raman endoscope.

PubMed

Komachi, Yuichi; Sato, Hidetoshi; Aizawa, Katsuo; Tashiro, Hideo

2005-08-01

We believe that we have developed the narrowest optical-fiber Raman probe ever reported, 600 microm in total diameter, that can be inserted into coronary arteries. The selection of suitable optical fibers, filters, and a processing method is discussed. Custom-made filters attached to the front end of a probe eliminate the background Raman signals of the optical fiber itself. The experimental evaluation of various optical fibers is carried out for the selection of suitable fibers. Measurement of the Raman spectra of an atherosclerotic lesion of a rabbit artery in vitro demonstrates the excellent performance of the micro-Raman probe.

Complete Fiber/Copper Cable Solution for Long-Term Temperature and Pressure Measurement in Supercritical Reservoirs and EGS Wells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pastouret, Alan; Gooijer, Frans; Overton, Bob

High Temperature insulated wire and optical fiber cable is a key enabling technology for the Geothermal Technologies Program (GTP). Without insulated electrical wires and optical fiber, downhole temperature and pressure sensors, flow meters and gauges cannot communicate with the surface. Unfortunately, there are currently no insulated electrical wire or fiber cable constructions capable of surviving for extended periods of deployment in a geothermal well (240-325°C) or supercritical (374°C) reservoir. This has severely hindered engineered reservoir creation, management and utilization, as hot zones and cool water intrusions cannot be understood over time. The lack of a insulated electrical wire and fibermore » cable solution is a fundamental limitation to the viability of this energy source. The High Temperature Downhole Tools target specification is development of tools and sensors for logging and monitoring wellbore conditions at depths of up to 10,000 meters and temperatures up to 374oC. It well recognized in the industry that no current electronic or fiber cable can be successfully deployed in a well and function successfully for more a few days at temperatures over 240oC. The goal of this project was to raise this performance level significantly. Prysmian Group’s objective in this project was to develop a complete, multi-purpose cable solution for long-term deployment in geothermal wells/reservoirs that can be used with the widest variety of sensors. In particular, the overall project objective was to produce a manufacturable cable design that can perform without serious degradation: • At temperatures up to 374°C; • At pressures up to 220 bar; • In a hydrogen-rich environment; and • For the life of the well (> 5 years). This cable incorporates: • Specialty optical fibers, with specific glass chemistry and high temperature and pressure protective coatings for data communication and distributed temperature and pressure sensing, and • High-temperature insulated wire conductors Prysmian Group has developed a geothermal fiber optic cable (GFOC) solution which incorporates novel glass chemistry for optical fibers to operate at the required bandwidths in high temperature/high pressure hydrogen rich environments with fiber protection, high temperature insulated conductors and protective cladding for cable components. The cable solution has been tested in a geothermal installation for 10 months. The electrical insulation and optical fibers have been validated through laboratory testing to ensure successful operation for greater than 5 years at 300°C, with the possibility of higher temperatures depending on the particular well environment. With the 300°C optical fiber and electrical insulation developments completed and validated in laboratory tests the greatest challenge to a complete 300°C cable solution was protecting the optical fibers in the cable. Optical fibers are typically incased in a protective tube where the tube is filled with a gel. The gel serves as mechanical protection, prevent moisture ingress, and can include hydrogen scavenging materials. A suitable gel for use at 300°C could not be identified and an industrialized alternative was not fully attained. Despite the problems encountered and the lower long-term operating temperature of the cable solution, the project showed success in developing a complete cable solution for a large portion of the geothermal wells in operation today. Further work to obtain the higher long-term temperature goal of the project can be achieved based on the knowledge gained in the current project. This project is significant for many reasons including the new materials science, manufacturing technology, energy independence, and jobs created and will create.« less

Optical probe with light fluctuation protection

DOEpatents

Da Silva, Luiz B.; Chase, Charles L.

2003-11-11

An optical probe for tissue identification includes an elongated body. Optical fibers are located within the elongated body for transmitting light to and from the tissue. Light fluctuation protection is associated with the optical fibers. In one embodiment the light fluctuation protection includes a reflective coating on the optical fibers to reduce stray light. In another embodiment the light fluctuation protection includes a filler with very high absorption located within the elongated body between the optical fibers.

Nanoimprint of a 3D structure on an optical fiber for light wavefront manipulation.

PubMed

Calafiore, Giuseppe; Koshelev, Alexander; Allen, Frances I; Dhuey, Scott; Sassolini, Simone; Wong, Edward; Lum, Paul; Munechika, Keiko; Cabrini, Stefano

2016-09-16

Integration of complex photonic structures onto optical fiber facets enables powerful platforms with unprecedented optical functionalities. Conventional nanofabrication technologies, however, do not permit viable integration of complex photonic devices onto optical fibers owing to their low throughput and high cost. In this paper we report the fabrication of a three-dimensional structure achieved by direct nanoimprint lithography on the facet of an optical fiber. Nanoimprint processes and tools were specifically developed to enable a high lithographic accuracy and coaxial alignment of the optical device with respect to the fiber core. To demonstrate the capability of this new approach, a 3D beam splitter has been designed, imprinted and optically characterized. Scanning electron microscopy and optical measurements confirmed the good lithographic capabilities of the proposed approach as well as the desired optical performance of the imprinted structure. The inexpensive solution presented here should enable advancements in areas such as integrated optics and sensing, achieving enhanced portability and versatility of fiber optic components.

Optical fiber technology development in Poland

NASA Astrophysics Data System (ADS)

Wójcik, Waldemar; Romaniuk, Ryszard

2010-09-01

Optical fiber technology is an important branch of science and technology, but also economy. Together with related disciplines it creates wider areas like optoelectronics and photonics. Optical fiber technology is developed in this country rather dynamically, proportionally to the available funds designed locally for research and applications. Recently this development was enhanced with considerable funds from European Operational Funds Innovative Economy POIG and Human Capital POKL. The paper summarizes the development of optical fiber technology in Poland from academic perspective during the period of last 2-3 years. The digest is very probably not full. An emphasis is put on development of optical fiber manufacturing methods. This development was illustrated by a few examples of optical fiber applications.

FIBER AND INTEGRATED OPTICS. OTHER TOPICS IN QUANTUM ELECTRONICS: Fiber-optic interferometers: control of spectral composition of the radiation and formation of high-intensity optical pulses

NASA Astrophysics Data System (ADS)

Bulushev, A. G.; Dianov, Evgenii M.; Kuznetsov, A. V.; Okhotnikov, O. G.; Paramonov, Vladimir M.; Tsarev, Vladimir A.

1990-05-01

A study was made of the use of single-mode fiber ring interferometers in narrowing the emission lines of semiconductor lasers and increasing the optical radiation power. Efficient coupling of radiation, emitted by a multifrequency injection laser with an external resonator, into a fiber ring interferometer was achieved both under cw and mode-locking conditions. Matching of the optical lengths of the external resonator and the fiber interferometer made it possible to determine the mode width for this laser. A method for generation of optical pulses in a fiber ring interferometer from cw frequency modulated radiation was developed.

Fiber optic sensors for corrosion detection

NASA Technical Reports Server (NTRS)

Smith, Alphonso C.

1993-01-01

The development of fiber optic sensors for the detection of a variety of material parameters has grown tremendously over the past several years. Additionally, the potential for analytical applications of fiber optic sensors have become more widely used. New pH sensors have also been developed using fiber optic techniques to detect fluorescence characteristics from immobilized fluorogenic reagent chemicals. The primary purpose of this research was to investigate the feasibility of using fiber optic sensors to detect the presence of Al(sup 3+) ions made in the process of environmental corrosion of aluminum materials. The Al(sup 3+) ions plus a variety of other type of metal ions can be detected using analytical techniques along with fiber optic sensors.

In-situ spectrophotometric probe

DOEpatents

Prather, W.S.

1992-12-15

A spectrophotometric probe is described for in situ absorption spectra measurements comprising a first optical fiber carrying light from a remote light source, a second optical fiber carrying light to a remote spectrophotometer, the proximal ends of the first and second optical fibers parallel and co-terminal, a planoconvex lens to collimate light from the first optical fiber, a reflecting grid positioned a short distance from the lens to reflect the collimated light back to the lens for focusing on the second optical fiber. The lens is positioned with the convex side toward the optical fibers. A substrate for absorbing analyte or an analyte and reagent mixture may be positioned between the lens and the reflecting grid. 5 figs.

Fiber optic laser rod

DOEpatents

Erickson, G.F.

1988-04-13

A laser rod is formed from a plurality of optical fibers, each forming an individual laser. Synchronization of the individual fiber lasers is obtained by evanescent wave coupling between adjacent optical fiber cores. The fiber cores are dye-doped and spaced at a distance appropriate for evanescent wave coupling at the wavelength of the selected dye. An interstitial material having an index of refraction lower than that of the fiber core provides the optical isolation for effective lasing action while maintaining the cores at the appropriate coupling distance. 2 figs.

7 CFR 1755.404 - Fiber optic cable telecommunications plant measurements.

Code of Federal Regulations, 2011 CFR

2011-01-01

... performed on each optical fiber within the cable. (2) Method of measurement. For single mode fibers, the end... on each optical fiber within the cable. (2) Method of measurement. For single mode fibers, the end-to...) RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS...

7 CFR 1755.404 - Fiber optic cable telecommunications plant measurements.

Code of Federal Regulations, 2010 CFR

2010-01-01

... performed on each optical fiber within the cable. (2) Method of measurement. For single mode fibers, the end... on each optical fiber within the cable. (2) Method of measurement. For single mode fibers, the end-to...) RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS...

Model of an axially strained weakly guiding optical fiber modal pattern

NASA Technical Reports Server (NTRS)

Egalon, Claudio O.; Rogowski, Robert S.

1991-01-01

Axial strain may be determined by monitoring the modal pattern variation of an optical fiber. In this paper we present the results of a numerical model that has been developed to calculate the modal pattern variation at the end of a weakly guiding optical fiber under axial strain. Whenever an optical fiber is under stress, the optical path length, the index of refraction and the propagation constants of each fiber mode change. In consequence, the modal phase term of the fields and the fiber output pattern are also modified. For multimode fibers, very complicated patterns result. The predicted patterns are presented, and an expression for the phase variation with strain is derived.

Fiber Optic Microphone

NASA Technical Reports Server (NTRS)

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

1999-01-01

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

Low-cost, high-precision micro-lensed optical fiber providing deep-micrometer to deep-nanometer-level light focusing.

PubMed

Wen, Sy-Bor; Sundaram, Vijay M; McBride, Daniel; Yang, Yu

2016-04-15

A new type of micro-lensed optical fiber through stacking appropriate high-refractive microspheres at designed locations with respect to the cleaved end of an optical fiber is numerically and experimentally demonstrated. This new type of micro-lensed optical fiber can be precisely constructed with low cost and high speed. Deep micrometer-scale and submicrometer-scale far-field light spots can be achieved when the optical fibers are multimode and single mode, respectively. By placing an appropriate teardrop dielectric nanoscale scatterer at the far-field spot of this new type of micro-lensed optical fiber, a deep-nanometer near-field spot can also be generated with high intensity and minimum joule heating, which is valuable in high-speed, high-resolution, and high-power nanoscale detection compared with traditional near-field optical fibers containing a significant portion of metallic material.

Fiber Optic System Test Results In A Tactical Military Aircraft

NASA Astrophysics Data System (ADS)

Uhlhorn, Roger W.; Greenwell, Roger A.

1980-09-01

The YAV-8B Electromagnetic Immunity and Flight-Test Program was established to evaluate the susceptibility of wire and optical fiber signal transmission lines to electromagnetic interference when these lines are installed in a graphite/epoxy composite wing and to demonstrate the flightworthiness of fiber optics interconnects in the vertical/ short takeoff and landing aircraft environment. In response, two fiber optic systems were designed, fabricated, and flight tested by McDonnell Aircraft Co. (MCAIR), a division of the McDonnell Douglas Corporation, on the two YAV-8B V/STOL flight test aircraft. The program successfully demonstrated that fiber optics are compatible with the attack aircraft environment. As a result, the full scale development AV-8B will incorporate fiber optics in a point-to-point data link. We describe here the fiber optic systems designs, test equipment development, cabling and connection requirements, fabrication and installation experience, and flight test program results.

Fiber-optic apparatus and method for measurement of luminescence and Raman scattering

DOEpatents

Myrick, M.L.; Angel, S.M.

1993-03-16

A dual fiber forward scattering optrode for Raman spectroscopy with the remote ends of the fibers in opposed, spaced relationship to each other to form a analyte sampling space therebetween and the method of measuring Raman spectra utilizing same are described. One optical fiber is for sending an exciting signal to the remote sampling space and, at its remote end, has a collimating microlens and an optical filter for filtering out background emissions generated in the fiber. The other optical fiber is for collecting the Raman scattering signal at the remote sampling space and, at its remote end, has a collimating microlens and an optical filter to prevent the exciting signal from the exciting fiber from entering the collection fiber and to thereby prevent the generation of background emissions in the collecting fiber.

Realization of a fiber optic sensor detecting the presence of a liquid

NASA Astrophysics Data System (ADS)

Guzowski, B.; Łakomski, M.; Nowogrodzki, K.

2016-11-01

Over the past thirty years, optical fibers have revolutionized the telecommunication market. Fiber optics play also important roles in other numerous applications. One of these applications is fiber sensing - very fast developing area. In this paper, realization of different configurations of a fiber optic sensor detecting the presence of liquid is presented. In the presented sensor, two multimode fibers (MMF) are placed opposite each other, where the first one transmits the light radiation, while the second one is a receiver. Due to the small size of the core (50 μm diameter), they had to be precisely positioned. Therefore the optical fibers were placed in the etched channels in the silicon substrate. In order to make sensors more sensitive, ball-lensed optical fibers were used. Four different diameters of lenses were examined. Sensitivity to the presence of liquids was compared in all realized sensors. Moreover, the influence of distance between the transmitting and receiving optical fiber on the received optical power is also described in this paper. All developed sensors were tested at 1300 nm wavelength. In the last part of this paper the detailed discussion is given.

Fiber optic-based biosensor

NASA Technical Reports Server (NTRS)

Ligler, Frances S.

1991-01-01

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

Compensated Fiber-Optic Frequency Distribution Equipment

DTIC Science & Technology

2010-11-01

fiber optic links have been developed and deployed, providing stability sufficient to transfer hydrogen maser-derived frequency references in intra...effectively compensate for the added noise and instability of an inter-facility fiber - optic frequency distribution link , it is important to understand the...dispersion (the variation in group velocity as a function of optical wavelength) may also affect the performance of the fiber optic link , when link

An Optical Fiber Sensor and Its Application in UAVs for Current Measurements

PubMed Central

Delgado, Felipe S.; Carvalho, João P.; Coelho, Thiago V. N.; Dos Santos, Alexandre B.

2016-01-01

In this paper, we propose and experimentally investigate an optical sensor based on a novel combination of a long-period fiber grating (LPFG) with a permanent magnet to measure electrical current in unmanned aerial vehicles (UAVs). The proposed device uses a neodymium magnet attached to the grating structure, which suffers from an electromagnetic force produced when the current flows in the wire of the UAV engine. Therefore, it causes deformation on the sensor and thus, different shifts occur in the resonant bands of the transmission spectrum of the LPFG. Finally, the results show that it is possible to monitor electrical current throughout the entire operating range of the UAV engine from 0 A to 10 A in an effective and practical way with good linearity, reliability and response time, which are desirable characteristics in electrical current sensing. PMID:27801798

Career Directions--Fiber Optic Installer

ERIC Educational Resources Information Center

Tech Directions, 2012

2012-01-01

Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of light through an optical fiber that is roughly the diameter of a human hair. The light forms an electromagnetic carrier wave that is modulated to carry information. Each optical fiber is capable of carrying an enormous amount of…

Overview of Fiber-Optical Sensors

NASA Technical Reports Server (NTRS)

Depaula, Ramon P.; Moore, Emery L.

1987-01-01

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.

46 CFR 111.60-6 - Fiber optic cable.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Fiber optic cable. 111.60-6 Section 111.60-6 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-6 Fiber optic cable. Each fiber optic cable must— (a) Be...

21 CFR 872.4620 - Fiber optic dental light.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Fiber optic dental light. 872.4620 Section 872...) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4620 Fiber optic dental light. (a) Identification. A fiber optic dental light is a device that is a light, usually AC-powered, that consists of glass or...

21 CFR 872.4620 - Fiber optic dental light.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Fiber optic dental light. 872.4620 Section 872...) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4620 Fiber optic dental light. (a) Identification. A fiber optic dental light is a device that is a light, usually AC-powered, that consists of glass or...

21 CFR 872.4620 - Fiber optic dental light.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Fiber optic dental light. 872.4620 Section 872...) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4620 Fiber optic dental light. (a) Identification. A fiber optic dental light is a device that is a light, usually AC-powered, that consists of glass or...

21 CFR 872.4620 - Fiber optic dental light.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Fiber optic dental light. 872.4620 Section 872...) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4620 Fiber optic dental light. (a) Identification. A fiber optic dental light is a device that is a light, usually AC-powered, that consists of glass or...

21 CFR 872.4620 - Fiber optic dental light.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Fiber optic dental light. 872.4620 Section 872...) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4620 Fiber optic dental light. (a) Identification. A fiber optic dental light is a device that is a light, usually AC-powered, that consists of glass or...

46 CFR 111.60-6 - Fiber optic cable.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Fiber optic cable. 111.60-6 Section 111.60-6 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-6 Fiber optic cable. Each fiber optic cable must— (a) Be...

46 CFR 111.60-6 - Fiber optic cable.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Fiber optic cable. 111.60-6 Section 111.60-6 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-6 Fiber optic cable. Each fiber optic cable must— (a) Be...

46 CFR 111.60-6 - Fiber optic cable.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Fiber optic cable. 111.60-6 Section 111.60-6 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-6 Fiber optic cable. Each fiber optic cable must— (a) Be...

46 CFR 111.60-6 - Fiber optic cable.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Fiber optic cable. 111.60-6 Section 111.60-6 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-6 Fiber optic cable. Each fiber optic cable must— (a) Be...

Everything You Always Wanted to Know about Fiber Optics but Were Afraid to Ask...

ERIC Educational Resources Information Center

Bunch, Robert M.

1993-01-01

Explains light-wave communication and optical fibers. The impact of fiber optics on communication is discussed; uses of fiber optic technology in elementary, secondary, and higher education are described; and possible futures of light-wave communication are considered, including Integrated Services Digital Networks and the National Research and…

78 FR 17187 - Notice of Intent To Grant Exclusive Patent License; Fiber Optic Sensor Systems Technology...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-20

...; Fiber Optic Sensor Systems Technology Corporation AGENCY: Department of the Navy, DoD. ACTION: Notice..., 2012, announcing an intent to grant to Fiber Optic Sensor Systems Technology Corporation, a revocable... the Navy hereby gives notice of its intent to grant to Fiber Optic Sensor Systems Technology...

Thermal Strain Analysis of Optic Fiber Sensors

PubMed Central

Her, Shiuh-Chuan; Huang, Chih-Ying

2013-01-01

An optical fiber sensor surface bonded onto a host structure and subjected to a temperature change is analytically studied in this work. The analysis is developed in order to assess the thermal behavior of an optical fiber sensor designed for measuring the strain in the host structure. For a surface bonded optical fiber sensor, the measuring sensitivity is strongly dependent on the bonding characteristics which include the protective coating, adhesive layer and the bonding length. Thermal stresses can be generated due to a mismatch of thermal expansion coefficients between the optical fiber and host structure. The optical fiber thermal strain induced by the host structure is transferred via the adhesive layer and protective coating. In this investigation, an analytical expression of the thermal strain and stress in the optical fiber is presented. The theoretical predictions are validated using the finite element method. Numerical results show that the thermal strain and stress are linearly dependent on the difference in thermal expansion coefficients between the optical fiber and host structure and independent of the thermal expansion coefficients of the adhesive and coating. PMID:23385407

Time-resolved spectroscopy and optical gain of silica-based fibers co-doped with Bi, Al and/or Ge, P, and Ti

NASA Astrophysics Data System (ADS)

Firstov, S. V.; Bufetov, I. A.; Khopin, V. F.; Umnikov, A. A.; Guryanov, A. N.; Dianov, E. M.

2009-04-01

The optical properties of optical fibers based on silica glass doped with bismuth and co-doped with aluminum oxides and/or germanium, phosphorus, and titanium oxides are studied. The optical loss and luminescence spectra of optical fibers substantially depend on the core composition. The gain spectra of single-mode optical fibers are measured in the IR range. It is demonstrated that the phosphorus-germanium-silicate optical fiber doped with bismuth exhibits a broad gain band (1270-1520 nm) when pumped at a wavelength of 1230 nm. It is also shown that the bismuth-aluminosilicate optical fibers additionally doped with Ge or Ti at about 1 at % have the gain spectra that are significantly narrower than the IR luminescence spectra (in contrast to the fibers that do not contain Ge and Ti). The intensity decay curves of the IR luminescence in such fibers indicate the presence of both short-lived (with the lifetime τ≤4 μs) and long-lived (τ ˜ 1 ms) energy levels in the bismuth active centers.

Performance of optical fibers in space radiation environment

NASA Astrophysics Data System (ADS)

Alam, M.; Abramczyk, J.; Manyam, U.; Farroni, J.; Guertin, D.

2017-11-01

The use of optical fibers in low earth orbiting (LEO) satellites is a source of concern due to the radiation environment in which these satellites operate and the reliability of devices based on these fibers. Although radiation induced damage in optical fibers cannot be avoided, it can certainly be minimized by intelligent engineering. Qualifying fibers for use in space is both time consuming and expensive, and manufacturers of satellites and their payloads have started to ask for radiation performance data from optical fiber vendors. Over time, Nufern has developed fiber designs, compositions and processes to make radiation hard fibers. Radiation performance data of a variety of fibers that find application in space radiation environment are presented.

Technology Validation of Optical Fiber Cables for Space Flight Environments

NASA Technical Reports Server (NTRS)

Ott, Melanie N.; Friedberg, Patricia; Day, John H. (Technical Monitor)

2000-01-01

Periodically, commercially available (COTS) optical fiber cable assemblies are characterized for space flight usage under the NASA Electronic Parts and Packaging Program (NEPP). The purpose of this is to provide a family of optical fiber cable options to a variety of different harsh environments typical to space flight missions. The optical fiber cables under test are evaluated to bring out known failure mechanisms that are expected to occur during a typical mission. The tests used to characterize COTS cables include: (1) vacuum exposure, (2) thermal cycling, and (3) radiation exposure. Presented here are the results of the testing conducted at NASA Goddard Space Flight Center on COTS optical fiber cables over this past year. Several optical fiber cables were characterized for their thermal stability both during and after thermal cycling. The results show how much preconditioning is necessary for a variety of available cables to remain thermally stable in a space flight environment. Several optical fibers of dimensions 100/140/172 microns were characterized for their radiation effects at -125 C using the dose rate requirements of International Space Station. One optical fiber cable in particular was tested for outgassing to verify whether an acrylate coated fiber could be used in a space flight optical cable configuration.

Synopsis of fiber optics in harsh environments

NASA Astrophysics Data System (ADS)

Pirich, Ronald

2014-09-01

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.

Frequency transfer via a two-way optical phase comparison on a multiplexed fiber network.

PubMed

Calosso, C E; Bertacco, E; Calonico, D; Clivati, C; Costanzo, G A; Frittelli, M; Levi, F; Mura, A; Godone, A

2014-03-01

We performed a two-way remote optical phase comparison on optical fiber. Two optical frequency signals were launched in opposite directions in an optical fiber and their phases were simultaneously measured at the other end. In this technique, the fiber noise is passively canceled, and we compared two optical frequencies at the ultimate 10(-21) stability level. The experiment was performed on a 47 km fiber that is part of the metropolitan network for Internet traffic. The technique relies on the synchronous measurement of the optical phases at the two ends of the link, which is here performed by digital electronics. This scheme offers some advantages with respect to active noise cancellation schemes, as the light travels only once in the fiber.

Fabrication and characterization of disordered polymer optical fibers for transverse Anderson localization of light.

PubMed

Karbasi, Salman; Frazier, Ryan J; Mirr, Craig R; Koch, Karl W; Mafi, Arash

2013-07-29

We develop and characterize a disordered polymer optical fiber that uses transverse Anderson localization as a novel waveguiding mechanism. The developed polymer optical fiber is composed of 80,000 strands of poly (methyl methacrylate) (PMMA) and polystyrene (PS) that are randomly mixed and drawn into a square cross section optical fiber with a side width of 250 μm. Initially, each strand is 200 μm in diameter and 8-inches long. During the mixing process of the original fiber strands, the fibers cross over each other; however, a large draw ratio guarantees that the refractive index profile is invariant along the length of the fiber for several tens of centimeters. The large refractive index difference of 0.1 between the disordered sites results in a small localized beam radius that is comparable to the beam radius of conventional optical fibers. The input light is launched from a standard single mode optical fiber using the butt-coupling method and the near-field output beam from the disordered fiber is imaged using a 40X objective and a CCD camera. The output beam diameter agrees well with the expected results from the numerical simulations. The disordered optical fiber presented in this work is the first device-level implementation of 2D Anderson localization, and can potentially be used for image transport and short-haul optical communication systems.

Fabrication and Characterization of Disordered Polymer Optical Fibers for Transverse Anderson Localization of Light

PubMed Central

Karbasi, Salman; Frazier, Ryan J.; Mirr, Craig R.; Koch, Karl W.; Mafi, Arash

2013-01-01

We develop and characterize a disordered polymer optical fiber that uses transverse Anderson localization as a novel waveguiding mechanism. The developed polymer optical fiber is composed of 80,000 strands of poly (methyl methacrylate) (PMMA) and polystyrene (PS) that are randomly mixed and drawn into a square cross section optical fiber with a side width of 250 μm. Initially, each strand is 200 μm in diameter and 8-inches long. During the mixing process of the original fiber strands, the fibers cross over each other; however, a large draw ratio guarantees that the refractive index profile is invariant along the length of the fiber for several tens of centimeters. The large refractive index difference of 0.1 between the disordered sites results in a small localized beam radius that is comparable to the beam radius of conventional optical fibers. The input light is launched from a standard single mode optical fiber using the butt-coupling method and the near-field output beam from the disordered fiber is imaged using a 40X objective and a CCD camera. The output beam diameter agrees well with the expected results from the numerical simulations. The disordered optical fiber presented in this work is the first device-level implementation of 2D Anderson localization, and can potentially be used for image transport and short-haul optical communication systems. PMID:23929276

Mode division multiplexing technology for single-fiber optical trapping axial-position adjustment.

PubMed

Liu, Zhihai; Wang, Lei; Liang, Peibo; Zhang, Yu; Yang, Jun; Yuan, Libo

2013-07-15

We demonstrate trapped yeast cell axial-position adjustment without moving the optical fiber in a single-fiber optical trapping system. The dynamic axial-position adjustment is realized by controlling the power ratio of the fundamental mode beam (LP01) and the low-order mode beam (LP11) generated in a normal single-core fiber. In order to separate the trapping positions produced by the two mode beams, we fabricate a special fiber tapered tip with a selective two-step method. A yeast cell of 6 μm diameter is moved along the optical axis direction for a distance of ~3 μm. To the best of our knowledge, this is the first demonstration of the trapping position adjustment without moving the fiber for single-fiber optical tweezers. The excitation and utilization of multimode beams in a single fiber constitutes a new development for single-fiber optical trapping and makes possible more practical applications in biomedical research fields.

Off-axis reflective optical apparatus

NASA Technical Reports Server (NTRS)

Ames, Lawrence L. (Inventor); Leary, David F. (Inventor); Mammini, Paul V. (Inventor)

2005-01-01

Embodiments of the present invention are directed to a simple apparatus and a convenient and accurate method of mounting the components to form an off-axis reflective optical apparatus such as a collimator. In one embodiment, an off-axis reflective optical apparatus comprises a mounting block having a ferrule holder support surface and an off-axis reflector support surface which is generally perpendicular to the ferrule holder support surface. An optical reflector is mounted on the off-axis reflector support surface and has a reflected beam centerline. The optical reflector has a conic reflective surface and a conic center. A ferrule holder is mounted on the ferrule holder support surface. The ferrule holder provides a ferrule for coupling to an optical fiber and orienting a fiber tip of the optical fiber along a fiber axis toward the optical reflector. The fiber axis is nonparallel to the reflected beam centerline. Prior to mounting the optical reflector to the off-axis reflector support surface and prior to mounting the ferrule holder to the ferrule holder support surface, the optical reflector is movable on the off-axis reflector surface and the ferrule holder is movable on the ferrule holder support surface to align the conic center of the optical reflector with respect to the fiber tip of the optical fiber, and the apparatus has at least one of the following features: (1) the optical reflector is movable on the off-axis reflector support surface to adjust a focus of the fiber tip with respect to the optical reflector, and (2) the ferrule holder is movable on the ferrule holder support surface to adjust the focus of the fiber tip with respect to the optical reflector.

Integral Field Spectroscopy of Markarian 273: Mapping High-Velocity Gas Flows and an Off-Nucleus Seyfert 2 Nebula.

PubMed

Colina; Arribas; Borne

1999-12-10

Integral field optical spectroscopy with the INTEGRAL fiber-based system is used to map the extended ionized regions and gas flows in Mrk 273, one of the closest ultraluminous infrared galaxies. The Hbeta and [O iii] lambda5007 maps show the presence of two distinct regions separated by 4&arcsec; (3.1 kpc) along position angle (P.A.) 240 degrees. The northeastern region coincides with the optical nucleus of the galaxy and shows the spectral characteristics of LINERs. The southwestern region is dominated by [O iii] emission and is classified as a Seyfert 2. Therefore, in the optical, Mrk 273 is an ultraluminous infrared galaxy with a LINER nucleus and an extended off-nucleus Seyfert 2 nebula. The kinematics of the [O iii] ionized gas shows (1) the presence of highly disturbed gas in the regions around the LINER nucleus, (2) a high-velocity gas flow with a peak-to-peak amplitude of 2.4x103 km s-1, and (3) quiescent gas in the outer regions (at 3 kpc). We hypothesize that the high-velocity flow is the starburst-driven superwind generated in an optically obscured nuclear starburst and that the quiescent gas is directly ionized by a nuclear source, similar to the ionization cones typically seen in Seyfert galaxies.

Instrument for fluorescence sensing of circulating cells with diffuse light in mice in vivo.

PubMed

Zettergren, Eric; Vickers, Dwayne; Runnels, Judith; Murthy, Shashi K; Lin, Charles P; Niedre, Mark

2012-03-01

Accurate quantification of circulating cell populations in mice is important in many areas of preclinical biomedical research. Normally, this is done either by extraction and analysis of small blood samples or, more recently, by using microscopy-based in vivo fluorescence flow cytometry. We describe a new technological approach to this problem using detection of diffuse fluorescent light from relatively large blood vessels in vivo. The diffuse fluorescence flow cytometer (DFFC) uses a laser to illuminate a mouse limb and an array of optical fibers coupled to a high-sensitivity photomultiplier tube array operating in photon counting mode to detect weak fluorescence signals from cells. We first demonstrate that the DFFC instrument is capable of detecting fluorescent microspheres and Vybrant-DiD-labeled cells in a custom-made optical flow phantom with similar size, optical properties, linear flow rates, and autofluorescence as a mouse limb. We also present preliminary data demonstrating that the DFFC is capable of detecting circulating cells in nude mice in vivo. In principle, this device would allow interrogation of the whole blood volume of a mouse in minutes, with sensitivity improvement by several orders of magnitude compared to current approaches. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).

Transverse strain measurements using fiber optic grating based sensors

NASA Technical Reports Server (NTRS)

Udd, Eric (Inventor)

1998-01-01

A system and method to sense the application of transverse stress to an optical fiber which includes a light source that producing a relatively wide spectrum light beam. The light beam is reflected or transmitted off of an optical grating in the core of an optical fiber that is transversely stressed either directly or by the exposure to pressure when the fiber is bifringent so that the optical fiber responds to the pressure to transversely stress its core. When transversely stressed, the optical grating produces a reflection or transmission from the light beam that has two peaks or minimums in its frequency spectrum whose spacing and/or spread are indicative of the forces applied to the fiber. One or more detectors sense the reflection or transmissions from the optical grating to produce an output representative of the applied force. Multiple optical gratings and detectors may be employed to simultaneously measure temperature or the forces at different locations along the fiber.

High-Q Microsphere Cavity for Laser Stabilization and Optoelectronic Microwave Oscillator

NASA Technical Reports Server (NTRS)

Ilchenko, Vladimir S.; Yao, X. Steve; Maleki, Lute

2000-01-01

With submillimeter size and optical Q up to approximately 10 (exp 10), microspheres with whispering-gallery (WG) modes are attractive new component for fiber-optics/photonics applications and a potential core in ultra-compact high-spectral-purity optical and microwave oscillators. In addition to earlier demonstrated optical locking of diode laser to WG mode in a microsphere, we report on microsphere application in the microwave optoelectronic oscillator, OEO. In OEO, a steady-state microwave modulation of optical carrier is obtained in a closed loop including electro-optical modulator, fiber-optic delay, detector and microwave amplifier. OEO demonstrates exceptionally low phase noise (-140 dBc/Hz at l0kHz from approximately 10GHz carrier) with a fiber length approximately 2km. Current technology allows to put all parts of the OEO, except the fiber, on the same chip. Microspheres, with their demonstrated Q equivalent to a kilometer fiber storage, can replace fiber delays in a truly integrated device. We have obtained microwave oscillation in microsphere-based OEO at 5 to 18 GHz, with 1310nm and 1550nm optical carrier, in two configurations: 1) with external DFB pump laser, and 2) with a ring laser including microsphere and a fiber optic amplifier. Also reported is a simple and efficient fiber coupler for microspheres facilitating their integration with existing fiber optics devices.

Optofluidic refractive-index sensor in step-index fiber with parallel hollow micro-channel.

PubMed

Lee, H W; Schmidt, M A; Uebel, P; Tyagi, H; Joly, N Y; Scharrer, M; Russell, P St J

2011-04-25

We present a simple refractive index sensor based on a step-index fiber with a hollow micro-channel running parallel to its core. This channel becomes waveguiding when filled with a liquid of index greater than silica, causing sharp dips to appear in the transmission spectrum at wavelengths where the glass-core mode phase-matches to a mode of the liquid-core. The sensitivity of the dip-wavelengths to changes in liquid refractive index is quantified and the results used to study the dynamic flow characteristics of fluids in narrow channels. Potential applications of this fiber microstructure include measuring the optical properties of liquids, refractive index sensing, biophotonics and studies of fluid dynamics on the nanoscale.

The FRD and transmission of the 270-m GRACES optical fiber link and a high numerical aperture fiber for astronomy

NASA Astrophysics Data System (ADS)

Pazder, John; Fournier, Paul; Pawluczyk, Rafal; van Kooten, Maaike

2014-07-01

We report results of the extensive development work done on the 270-m optical fiber link for the GRACES project and a preliminary investigations into a high numerical aperture fiber for astronomy. The Gemini Remote Access CFHT ESPaDOnS Spectrograph (GRACES) is an instrumentation experiment to link ESPaDOnS, a bench-mounted highresolution optical spectrograph at CFHT, to the Gemini-North telescope with an optical fiber link. A 270-m fiber link with less than 14% Focal Ratio Degradation (FRD) has been developed jointly by HIA and FiberTech Optica for the experiment. A preliminary study has been conducted by HIA into a high numerical aperture fiber (0.26 numerical aperture) with the intended application of wide field optical spectrographs fiber fed from the telescope prime focus. The Laboratory test results of FRD, transmission, and stability for the GRACES fiber link and preliminary FRD measurements of the high numerical aperture fiber tests are reported.

Distributed transverse stress measurement along an optic fiber using polarimetric OFDR.

PubMed

Wei, Changjiang; Chen, Hongxin; Chen, Xiaojun; Chen, David; Li, Zhihong; Yao, X Steve

2016-06-15

We report a novel polarimetric optical frequency domain reflectometer (P-OFDR) that can simultaneously measure both space-resolved transverse stresses and light back-reflections along an optic fiber with sub-mm spatial resolution. By inducing transversal stresses and optical back-reflections at multiple points along a length of optic fiber, we demonstrate that our system can unambiguously distinguish the stresses from the back-reflections of a fiber with a fiber length longer than 800 m, a spatial resolution of 0.5 mm, a maximum stress level of up to 200 kpsi (1379 Mpa), a minimum stress of about 10 kpsi (69 Mpa), and a stress measurement uncertainty of 10%. We show that our P-OFDR can clearly identify the locations and magnitudes of the stresses inside a fiber coil induced during a fiber winding process. The P-OFDR can be used for fiber health monitoring for critical fiber links, fiber gyro coil characterization, and other distributed fiber sensing applications.

Evaluation of six holmium:YAG optical fibers for ureteroscopy: What's new in 2009?

NASA Astrophysics Data System (ADS)

Knudsen, Bodo E.; Teichman, Joel M. H.

2010-02-01

The holmium:yttrium aluminum garnet (YAG) laser is the gold standard laser for intracorporeal lithotripsy.1 Optical fibers are utilized to transmit laser energy to the surface of a stone for fragmentation via a predominant photothermal mechanism.2 Previous work has demonstrated that performance characteristics of holmium:YAG optical fibers used for laser lithotripsy varies. Performance may difference not only between fibers made by different manufacturers but also between individual fibers produced by the same manufacturer.3,4 Fiber failure with bending, such as during lower pole ureterorenoscopy, can lead to catastrophic endoscope damage resulting in costly repair. Manufacturers continue to develop new holmium:YAG optical fibers. In this study we evaluate a series of newly commercially available fibers using a previously designed testing protocol. This study was designed to determine the performance and threshold for failure of six newly available holmium:YAG laser fibers from Cook Medical and Fibertech Gmbh. We hypothesize that fiber performance will continue to vary amongst different holmium:YAG optical fibers.

Optical fiber loops and helices: tools for integrated photonic device characterization and microfluidic trapping

NASA Astrophysics Data System (ADS)

Ren, Yundong; Zhang, Rui; Ti, Chaoyang; Liu, Yuxiang

2016-09-01

Tapered optical fibers can deliver guided light into and carry light out of micro/nanoscale systems with low loss and high spatial resolution, which makes them ideal tools in integrated photonics and microfluidics. Special geometries of tapered fibers are desired for probing monolithic devices in plane as well as optical manipulation of micro particles in fluids. However, for many specially shaped tapered fibers, it remains a challenge to fabricate them in a straightforward, controllable, and repeatable way. In this work, we fabricated and characterized two special geometries of tapered optical fibers, namely fiber loops and helices, that could be switched between one and the other. The fiber loops in this work are distinct from previous ones in terms of their superior mechanical stability and high optical quality factors in air, thanks to a post-annealing process. We experimentally measured an intrinsic optical quality factor of 32,500 and a finesse of 137 from a fiber loop. A fiber helix was used to characterize a monolithic cavity optomechanical device. Moreover, a microfluidic "roller coaster" was demonstrated, where microscale particles in water were optically trapped and transported by a fiber helix. Tapered fiber loops and helices can find various applications ranging from on-the-fly characterization of integrated photonic devices to particle manipulation and sorting in microfluidics.

Flight testing of a fiber optic temperature sensor

NASA Technical Reports Server (NTRS)

Finney, M. J.; Tregay, G. W.; Calabrese, P. R.

1993-01-01

A fiber optic temperature sensor (FOTS) system consisting of an optical probe, a flexible fiber optic cable, and an electro-optic signal processor was fabricated to measure the gas temperature in a turbine engine. The optical probe contained an emissive source embedded in a sapphire lightguide coupled to a fiber-optic jumper cable and was retrofitted into an existing thermocouple probe housing. The flexible fiber optic cable was constructed with 200 micron core, polyimide-coated fiber and was ruggedized for an aircraft environment. The electro-optic signal processing unit was used to ratio the intensities of two wavelength intervals and provided an analog output value of the indicated temperature. Subsequently, this optical sensor system was installed on a NASA Dryden F-15 Highly Integrated Digital Electronic Control (HIDEC) Aircraft Engine and several flight tests were conducted. Over the course of flight testing, the FOTS system's response was proportional to the average of the existing thermocouples sensing the changes in turbine engine thermal conditions.

Performance evaluation of multi-stratum resources optimization with network functions virtualization for cloud-based radio over optical fiber networks.

PubMed

Yang, Hui; He, Yongqi; Zhang, Jie; Ji, Yuefeng; Bai, Wei; Lee, Young

2016-04-18

Cloud radio access network (C-RAN) has become a promising scenario to accommodate high-performance services with ubiquitous user coverage and real-time cloud computing using cloud BBUs. In our previous work, we implemented cross stratum optimization of optical network and application stratums resources that allows to accommodate the services in optical networks. In view of this, this study extends to consider the multiple dimensional resources optimization of radio, optical and BBU processing in 5G age. We propose a novel multi-stratum resources optimization (MSRO) architecture with network functions virtualization for cloud-based radio over optical fiber networks (C-RoFN) using software defined control. A global evaluation scheme (GES) for MSRO in C-RoFN is introduced based on the proposed architecture. The MSRO can enhance the responsiveness to dynamic end-to-end user demands and globally optimize radio frequency, optical and BBU resources effectively to maximize radio coverage. The efficiency and feasibility of the proposed architecture are experimentally demonstrated on OpenFlow-based enhanced SDN testbed. The performance of GES under heavy traffic load scenario is also quantitatively evaluated based on MSRO architecture in terms of resource occupation rate and path provisioning latency, compared with other provisioning scheme.

Nonlinear optics in hollow-core photonic bandgap fibers.

PubMed

Bhagwat, Amar R; Gaeta, Alexander L

2008-03-31

Hollow-core photonic-bandgap fibers provide a new geometry for the realization and enhancement of many nonlinear optical effects. Such fibers offer novel guidance and dispersion properties that provide an advantage over conventional fibers for various applications. In this review we summarize the nonlinear optics experiments that have been performed using these hollow-core fibers.

Fiber optic choline biosensor

NASA Astrophysics Data System (ADS)

Wang, Hong; Cao, Xiaojian; Jia, Ke; Chai, Xueting; Lu, Hua; Lu, Zuhong

2001-10-01

A fiber optic fluorescence biosensor for choline is introduced in this paper. Choline is an important neurotransmitter in mammals. Due to the growing needs for on-site clinical monitoring of the choline, much effect has been devoted to develop choline biosensors. Fiber-optic fluorescence biosensors have many advantages, including miniaturization, flexibility, and lack of electrical contact and interference. The choline fiber-optic biosensor we designed implemented a bifurcated fiber to perform fluorescence measurements. The light of the blue LED is coupled into one end of the fiber as excitation and the emission spectrum from sensing film is monitored by fiber-spectrometer (S2000, Ocean Optics) through the other end of the fiber. The sensing end of the fiber is coated with Nafion film dispersed with choline oxidase and oxygen sensitive luminescent Ru(II) complex (Tris(2,2'-bipyridyl)dichlororuthenium(II), hexahydrate). Choline oxidase catalyzes the oxidation of choline to betaine and hydrogen peroxide while consuming oxygen. The fluorescence intensity of oxygen- sensitive Ru(II) are related to the choline concentration. The response of the fiber-optic sensor in choline solution is represented and discussed. The result indicates a low-cost, high-performance, portable choline biosensor.

Curved Piezoelectric Actuators for Stretching Optical Fibers

NASA Technical Reports Server (NTRS)

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

2008-01-01

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

Distributed strain measurements using fiber Bragg gratings in small-diameter optical fiber and low-coherence reflectometry.

PubMed

Coric, Dragan; Lai, Marco; Botsis, John; Luo, Aiping; Limberger, Hans G

2010-12-06

Optical low coherence reflectometry and fiber Bragg gratings written in small diameter (50 micrometer) optical fibers were used for measurements of non-homogenous internal strain fields inside an epoxy specimen with sub-grating length resolution. The results were compared with measurements using Fiber Bragg gratings in standard size (125 micrometer) single mode fibers and show that smaller fibers are less intrusive at stress heterogeneities.

Optical-fiber-based Mueller optical coherence tomography.

PubMed

Jiao, Shuliang; Yu, Wurong; Stoica, George; Wang, Lihong V

2003-07-15

An optical-fiber-based multichannel polarization-sensitive Mueller optical coherence tomography (OCT) system was built to acquire the Jones or Mueller matrix of a scattering medium, such as biological tissue. For the first time to our knowledge, fiber-based polarization-sensitive OCT was dynamically calibrated to eliminate the polarization distortion caused by the single-mode optical fiber in the sample arm, thereby overcoming a key technical impediment to the application of optical fibers in this technology. The round-trip Jones matrix of the sampling fiber was acquired from the reflecting surface of the sample for each depth scan (A scan) with our OCT system. A new rigorous algorithm was then used to retrieve the calibrated polarization properties of the sample. This algorithm was validated with experimental data. The skin of a rat was imaged with this fiber-based system.

Nanoparticle coated optical fibers for single microbubble generation

NASA Astrophysics Data System (ADS)

Pimentel-Domínguez, Reinher; Hernández-Cordero, Juan

2011-09-01

The study of bubbles and bubbly flows is important in various fields such as physics, chemistry, medicine, geophysics, and even the food industry. A wide variety of mechanical and acoustic techniques have been reported for bubble generation. Although a single bubble may be generated with these techniques, controlling the size and the mean lifetime of the bubble remains a difficult task. Most of the optical methods for generation of microbubbles involve high-power pulsed laser sources focused in absorbing media such as liquids or particle solutions. With these techniques, single micron-sized bubbles can be generated with typical mean lifetimes ranging from nano to microseconds. The main problem with these bubbles is their abrupt implosion: this produces a shock wave that can potentially produce damages on the surroundings. These effects have to be carefully controlled in biological applications and in laser surgery, but thus far, not many options are available to effectively control micron-size bubble growth. In this paper, we present a new technique to generate microbubbles in non-absorbing liquids. In contrast to previous reports, the proposed technique uses low-power and a CW radiation from a laser diode. The laser light is guided through an optical fiber whose output end has been coated with nanostructures. Upon immersing the tip of the fiber in ethanol or water, micron-size bubbles can be readily generated. With this technique, bubble growth can be controlled through adjustments on the laser power. We have obtained micron-sized bubbles with mean lifetimes in the range of seconds. Furthermore, the generated bubbles do not implode, as verified with a high-speed camera and flow visualization techniques.

On-Board Fiber-Optic Network Architectures for Radar and Avionics Signal Distribution

NASA Technical Reports Server (NTRS)

Alam, Mohammad F.; Atiquzzaman, Mohammed; Duncan, Bradley B.; Nguyen, Hung; Kunath, Richard

2000-01-01

Continued progress in both civil and military avionics applications is overstressing the capabilities of existing radio-frequency (RF) communication networks based on coaxial cables on board modem aircrafts. Future avionics systems will require high-bandwidth on- board communication links that are lightweight, immune to electromagnetic interference, and highly reliable. Fiber optic communication technology can meet all these challenges in a cost-effective manner. Recently, digital fiber-optic communication systems, where a fiber-optic network acts like a local area network (LAN) for digital data communications, have become a topic of extensive research and development. Although a fiber-optic system can be designed to transport radio-frequency (RF) signals, the digital fiber-optic systems under development today are not capable of transporting microwave and millimeter-wave RF signals used in radar and avionics systems on board an aircraft. Recent advances in fiber optic technology, especially wavelength division multiplexing (WDM), has opened a number of possibilities for designing on-board fiber optic networks, including all-optical networks for radar and avionics RF signal distribution. In this paper, we investigate a number of different novel approaches for fiber-optic transmission of on-board VHF and UHF RF signals using commercial off-the-shelf (COTS) components. The relative merits and demerits of each architecture are discussed, and the suitability of each architecture for particular applications is pointed out. All-optical approaches show better performance than other traditional approaches in terms of signal-to-noise ratio, power consumption, and weight requirements.

Residual strain sensor using Al-packaged optical fiber and Brillouin optical correlation domain analysis.

PubMed

Choi, Bo-Hun; Kwon, Il-Bum

2015-03-09

We propose a distributed residual strain sensor that uses an Al-packaged optical fiber for the first time. The residual strain which causes Brillouin frequency shifts in the optical fiber was measured using Brillouin optical correlation domain analysis with 2 cm spatial resolution. We quantified the Brillouin frequency shifts in the Al-packaged optical fiber by the tensile stress and compared them for a varying number of Al layers in the optical fiber. The Brillouin frequency shift of an optical fiber with one Al layer had a slope of 0.038 MHz/με with respect to tensile stress, which corresponds to 78% of that for an optical fiber without Al layers. After removal of the stress, 87% of the strain remained as residual strain. When different tensile stresses were randomly applied, the strain caused by the highest stress was the only one detected as residual strain. The residual strain was repeatedly measured for a time span of nine months for the purpose of reliability testing, and there was no change in the strain except for a 4% reduction, which is within the error tolerance of the experiment. A composite material plate equipped with our proposed Al-packaged optical fiber sensor was hammered for impact experiment and the residual strain in the plate was successfully detected. We suggest that the Al-packaged optical fiber can be adapted as a distributed strain sensor for smart structures, including aerospace structures.

Fiber-optic fluorescence imaging

PubMed Central

Flusberg, Benjamin A; Cocker, Eric D; Piyawattanametha, Wibool; Jung, Juergen C; Cheung, Eunice L M; Schnitzer, Mark J

2010-01-01

Optical fibers guide light between separate locations and enable new types of fluorescence imaging. Fiber-optic fluorescence imaging systems include portable handheld microscopes, flexible endoscopes well suited for imaging within hollow tissue cavities and microendoscopes that allow minimally invasive high-resolution imaging deep within tissue. A challenge in the creation of such devices is the design and integration of miniaturized optical and mechanical components. Until recently, fiber-based fluorescence imaging was mainly limited to epifluorescence and scanning confocal modalities. Two new classes of photonic crystal fiber facilitate ultrashort pulse delivery for fiber-optic two-photon fluorescence imaging. An upcoming generation of fluorescence imaging devices will be based on microfabricated device components. PMID:16299479

Nondestructive evaluation of composite materials by pulsed time domain methods in imbedded optical fibers

NASA Technical Reports Server (NTRS)

Claus, R. O.; Bennett, K. D.; Jackson, B. S.

1986-01-01

The application of fiber-optical time domain reflectometry (OTDR) to nondestructive quantitative measurements of distributed internal strain in graphite-epoxy composites, using optical fiber waveguides imbedded between plies, is discussed. The basic OTDR measurement system is described, together with the methods used to imbed optical fibers within composites. Measurement results, system limitations, and the effect of the imbedded fiber on the integrity of the host composite material are considered.

Optical Fiber-Tip Sensors Based on In-Situ µ-Printed Polymer Suspended-Microbeams.

PubMed

Yao, Mian; Ouyang, Xia; Wu, Jushuai; Zhang, A Ping; Tam, Hwa-Yaw; Wai, P K A

2018-06-05

Miniature optical fiber-tip sensors based on directly µ-printed polymer suspended-microbeams are presented. With an in-house optical 3D μ-printing technology, SU-8 suspended-microbeams are fabricated in situ to form Fabry⁻Pérot (FP) micro-interferometers on the end face of standard single-mode optical fiber. Optical reflection spectra of the fabricated FP micro-interferometers are measured and fast Fourier transform is applied to analyze the cavity of micro-interferometers. The applications of the optical fiber-tip sensors for refractive index (RI) sensing and pressure sensing, which showed 917.3 nm/RIU to RI change and 4.29 nm/MPa to pressure change, respectively, are demonstrated in the experiments. The sensors and their optical µ-printing method unveil a new strategy to integrate complicated microcomponents on optical fibers toward 'lab-on-fiber' devices and applications.

Optical Power Transfer System for Powering a Remote Mobility System for Multiple Missions

NASA Technical Reports Server (NTRS)

Hogan, Bartholomew P. (Inventor); Stone, William C. (Inventor)

2016-01-01

An optical power transfer system for powering a remote mobility system for multiple missions comprising a high power source and a chilling station connected to a laser source. The laser source transmits a high optical energy to a beam switch assembly via an optical fiber. The beam switch assembly is optically connected to actively cooled fiber spoolers. Docking stations are adapted for securing the fiber spoolers until alternatively ready for use by a remote mobility system. The remote mobility system is optically connected to the fiber spoolers and has a receiving port adapted for securing the fiber spoolers thereon. The fiber spooler transmits the optical energy to a power conversion system which converts the optical energy received to another usable form of energy. More than one power source may be used where the remote mobility system transfers from one source to another while maintaining an operational radius to each source.

In microfluidico: Recreating in vivo hemodynamics using miniaturized devices

PubMed Central

Zhu, Shu; Herbig, Bradley A.; Li, Ruizhi; Colace, Thomas V.; Muthard, Ryan W.; Neeves, Keith B.; Diamond, Scott L.

2016-01-01

Microfluidic devices create precisely controlled reactive blood flows and typically involve: (i) validated anticoagulation/pharmacology protocols, (ii) defined reactive surfaces, (iii) defined flow-transport regimes, and (iv) optical imaging. An 8-channel device can be run at constant flow rate or constant pressure drop for blood perfusion over a patterned collagen, collagen/kaolin, or collagen/tissue factor (TF) to measure platelet, thrombin, and fibrin dynamics during clot growth. A membrane-flow device delivers a constant flux of platelet agonists or coagulation enzymes into flowing blood. A trifurcated device sheaths a central blood flow on both sides with buffer, an ideal approach for on-chip recalcification of citrated blood or drug delivery. A side-view device allows clotting on a porous collagen/TF plug at constant pressure differential across the developing clot. The core-shell architecture of clots made in mouse models can be replicated in this device using human blood. For pathological flows, a stenosis device achieves shear rates of >100,000 s−1 to drive plasma von Willebrand factor (VWF) to form thick long fibers on collagen. Similarly, a micropost-impingement device creates extreme elongational and shear flows for VWF fiber formation without collagen. Overall, microfluidics are ideal for studies of clotting, bleeding, fibrin polymerization/fibrinolysis, cell/clot mechanics, adhesion, mechanobiology, and reaction-transport dynamics. PMID:26600269

Fiber-optic push-pull sensor systems

NASA Technical Reports Server (NTRS)

Gardner, David L.; Brown, David A.; Garrett, Steven L.

1991-01-01

Fiber-optic push-pull sensors are those which exploit the intrinsically differential nature of an interferometer with concommitant benefits in common-mode rejection of undesired effects. Several fiber-optic accelerometer and hydrophone designs are described. Additionally, the recent development at the Naval Postgraduate School of a passive low-cost interferometric signal demodulator permits the development of economical fiber-optic sensor systems.

System for diffusing light from an optical fiber or light guide

DOEpatents

Maitland, Duncan J [Pleasant Hill, CA; Wilson, Thomas S [San Leandro, CA; Benett, William J [Livermore, CA; Small, IV, Ward [

2008-06-10

A system for diffusing light from an optical fiber wherein the optical fiber is coupled to a light source, comprising forming a polymer element adapted to be connected to the optical fiber and incorporating a scattering element with the polymer element wherein the scattering element diffuses the light from the polymer element. The apparatus of the present invention comprises a polymer element operatively connected to the optical fiber and a scattering element operatively connected with the shape polymer element that diffuses the light from the polymer element.

Modulated-splitting-ratio fiber-optic temperature sensor

NASA Technical Reports Server (NTRS)

Beheim, Glenn; Anthan, Donald J.; Rys, John R.; Fritsch, Klaus; Ruppe, Walter A.

1988-01-01

A fiber-optic temperature sensor is described, which uses a small silicon beamsplitter whose splitting ratio varies as a function of temperature. A four-beam technique is used to measure the sensor's temperature-indicating splitting ratio. This referencing method provides a measurement that is largely independent of the transmission properties of the sensor's optical fiber link. A significant advantage of this sensor, relative to other fiber-optic sensors, is its high stability, which permits the fiber-optic components to be readily substituted, thereby simplifying the sensor's installation and maintenance.

Cryogenic fiber optic temperature sensor and method of manufacturing the same

NASA Technical Reports Server (NTRS)

Kochergin, Vladimir (Inventor)

2012-01-01

This invention teaches the fiber optic sensors temperature sensors for cryogenic temperature range with improved sensitivity and resolution, and method of making said sensors. In more detail, the present invention is related to enhancement of temperature sensitivity of fiber optic temperature sensors at cryogenic temperatures by utilizing nanomaterials with a thermal expansion coefficient that is smaller than the thermal expansion coefficient of the optical fiber but larger in absolute value than the thermal expansion coefficient of the optical fiber at least over a range of temperatures.

Testing of Sapphire Optical Fiber and Sensors in Intense Radiation Fields When Subjected to Very High Temperatures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blue, Thomas; Windl, Wolfgang

The primary objective of this project was to determine the optical attenuation and signal degradation of sapphire optical fibers & sensors (temperature & strain), in-situ, operating at temperatures up to 1500°C during reactor irradiation through experiments and modeling. The results will determine the feasibility of extending sapphire optical fiber-based instrumentation to extremely high temperature radiation environments. This research will pave the way for future testing of sapphire optical fibers and fiber-based sensors under conditions expected in advanced high temperature reactors.

Fiber-optic strain gauge with attached ends and unattached microbend section

DOEpatents

Weiss, J.D.

1992-07-21

A strain gauge is made of an optical fiber into which quasi-sinusoidal microbends have been permanently introduced. The permanent microbends cause a reduction in the fiber's optical transmission, but, when the gauge is attached to a substrate that is subsequently strained, the amplitude of the deformations will diminish and the optical transmission through the fiber will increase. An apparatus and process for manufacturing these microbends into the optical fiber through a heat-set process is employed; this apparatus and process includes a testing and calibration system. 5 figs.

Objective-lens-free Fiber-based Position Detection with Nanometer Resolution in a Fiber Optical Trapping System.

PubMed

Ti, Chaoyang; Ho-Thanh, Minh-Tri; Wen, Qi; Liu, Yuxiang

2017-10-13

Position detection with high accuracy is crucial for force calibration of optical trapping systems. Most existing position detection methods require high-numerical-aperture objective lenses, which are bulky, expensive, and difficult to miniaturize. Here, we report an affordable objective-lens-free, fiber-based position detection scheme with 2 nm spatial resolution and 150 MHz bandwidth. This fiber based detection mechanism enables simultaneous trapping and force measurements in a compact fiber optical tweezers system. In addition, we achieved more reliable signal acquisition with less distortion compared with objective based position detection methods, thanks to the light guiding in optical fibers and small distance between the fiber tips and trapped particle. As a demonstration of the fiber based detection, we used the fiber optical tweezers to apply a force on a cell membrane and simultaneously measure the cellular response.

Dispersion properties of plasma cladded annular optical fiber

NASA Astrophysics Data System (ADS)

KianiMajd, M.; Hasanbeigi, A.; Mehdian, H.; Hajisharifi, K.

2018-05-01

One of the considerable problems in a conventional image transferring fiber optic system is the two-fold coupling of propagating hybrid modes. In this paper, using a simple and practical analytical approach based on exact modal vectorial analysis together with Maxwell's equations, we show that applying plasma as a cladding medium of an annular optical fiber can remove this defect of conventional fiber optic automatically without any external instrument as the polarization beam splitter. Moreover, the analysis indicates that the presence of plasma in the proposed optical fiber could extend the possibilities for controlling the propagation property. The proposed structure presents itself as a promising route to advanced optical processing and opens new avenues in applied optics and photonics.

HARM processing techniques for MEMS and MOEMS devices using bonded SOI substrates and DRIE

NASA Astrophysics Data System (ADS)

Gormley, Colin; Boyle, Anne; Srigengan, Viji; Blackstone, Scott C.

2000-08-01

Silicon-on-Insulator (SOI) MEMS devices (1) are rapidly gaining popularity in realizing numerous solutions for MEMS, especially in the optical and inertia application fields. BCO recently developed a DRIE trench etch, utilizing the Bosch process, and refill process for high voltage dielectric isolation integrated circuits on thick SOI substrates. In this paper we present our most recently developed DRIE processes for MEMS and MOEMS devices. These advanced etch techniques are initially described and their integration with silicon bonding demonstrated. This has enabled process flows that are currently being utilized to develop optical router and filter products for fiber optics telecommunications and high precision accelerometers.

New method for calculating the coupling coefficient in graded index optical fibers

NASA Astrophysics Data System (ADS)

Savović, Svetislav; Djordjevich, Alexandar

2018-05-01

A simple method is proposed for determining the mode coupling coefficient D in graded index multimode optical fibers. It only requires observation of the output modal power distribution P(m, z) for one fiber length z as the Gaussian launching modal power distribution changes, with the Gaussian input light distribution centered along the graded index optical fiber axis (θ0 = 0) without radial offset (r0 = 0). A similar method we previously proposed for calculating the coupling coefficient D in a step-index multimode optical fibers where the output angular power distributions P(θ, z) for one fiber length z with the Gaussian input light distribution launched centrally along the step-index optical fiber axis (θ0 = 0) is needed to be known.

A modular optical sensor

NASA Astrophysics Data System (ADS)

Conklin, John Albert

This dissertation presents the design of a modular, fiber-optic sensor and the results obtained from testing the modular sensor. The modular fiber-optic sensor is constructed in such manner that the sensor diaphragm can be replaced with different configurations to detect numerous physical phenomena. Additionally, different fiber-optic detection systems can be attached to the sensor. Initially, the modular sensor was developed to be used by university of students to investigate realistic optical sensors and detection systems to prepare for advance studies of micro-optical mechanical systems (MOMS). The design accomplishes this by doing two things. First, the design significantly lowers the costs associated with studying optical sensors by modularizing the sensor design. Second, the sensor broadens the number of physical phenomena that students can apply optical sensing techniques to in a fiber optics sensor course. The dissertation is divided into seven chapters covering the historical development of fiber-optic sensors, a theoretical overview of fiber-optic sensors, the design, fabrication, and the testing of the modular sensor developed in the course of this work. Chapter 1 discusses, in detail, how this dissertation is organized and states the purpose of the dissertation. Chapter 2 presents an historical overview of the development of optical fibers, optical pressure sensors, and fibers, optical pressure sensors, and optical microphones. Chapter 3 reviews the theory of multi-fiber optic detection systems, optical microphones, and pressure sensors. Chapter 4 presents the design details of the modular, optical sensor. Chapter 5 delves into how the modular sensor is fabricated and how the detection systems are constructed. Chapter 6 presents the data collected from the microphone and pressure sensor configurations of the modular sensor. Finally, Chapter 7 discusses the data collected and draws conclusions about the design based on the data collected. Chapter 7 also presents future work needed to expand the functionality and utility of the modular sensor.

MAS Bulletin. GY-90 Fiber Optic Gyro

DTIC Science & Technology

1989-07-20

487 GY.9O Fiber Optic Gyro Background. Elettronica San Giorgio ELSAG S.p.A., Genoa, Italy, has developed a fiber optic gyro (FOG) for use on short...to the length of ELSAG S.p.A., Naval Systems Division, Via G. Puccini, 2-16154 the optical path and an extremely long optical path can be Genoa, Italy...Telephone 39 10/60011, Fax 39 10/607329, Telex achieved in a small size by using a many-turn coil of optical fiber. 270660/213847 ELSAG 1. There are

Fiber-Optic Terahertz Data-Communication Networks

NASA Technical Reports Server (NTRS)

Chua, Peter L.; Lambert, James L.; Morookian, John M.; Bergman, Larry A.

1994-01-01

Network protocols implemented in optical domain. Fiber-optic data-communication networks utilize fully available bandwidth of single-mode optical fibers. Two key features of method: use of subpicosecond laser pulses as carrier signals and spectral phase modulation of pulses for optical implementation of code-division multiple access as multiplexing network protocol. Local-area network designed according to concept offers full crossbar functionality, security of data in transit through network, and capacity about 100 times that of typical fiber-optic local-area network in current use.

Characterization of the stress and refractive-index distributions in optical fibers and fiber-based devices

NASA Astrophysics Data System (ADS)

Hutsel, Michael R.

2011-07-01

Optical fiber technology continues to advance rapidly as a result of the increasing demands on communication systems and the expanding use of fiber-based sensing. New optical fiber types and fiber-based communications components are required to permit higher data rates, an increased number of channels, and more flexible installation requirements. Fiber-based sensors are continually being developed for a broad range of sensing applications, including environmental, medical, structural, industrial, and military. As optical fibers and fiber-based devices continue to advance, the need to understand their fundamental physical properties increases. The residual-stress distribution (RSD) and the refractive-index distribution (RID) play fundamental roles in the operation and performance of optical fibers. Custom RIDs are used to tailor the transmission properties of fibers used for long-distance transmission and to enable fiber-based devices such as long-period fiber gratings (LPFGs). The introduction and modification of RSDs enable specialty fibers, such as polarization-maintaining fiber, and contribute to the operation of fiber-based devices. Furthermore, the RSD and the RID are inherently linked through the photoelastic effect. Therefore, both the RSD and the RID need to be characterized because these fundamental properties are coupled and affect the fabrication, operation, and performance of fibers and fiber-based devices. To characterize effectively the physical properties of optical fibers, the RSD and the RID must be measured without perturbing or destroying the optical fiber. Furthermore, the techniques used must not be limited in detecting small variations and asymmetries in all directions through the fiber. Finally, the RSD and the RID must be characterized concurrently without moving the fiber to enable the analysis of the relationship between the RSD and the RID. Although many techniques exist for characterizing the residual stress and the refractive index in optical fibers, there is no existing methodology that meets all of these requirements. Therefore, the primary objective of the research presented in this thesis was to provide a methodology that is capable of characterizing concurrently the three-dimensional RSD and RID in optical fibers and fiber-based devices. This research represents a detailed study of the requirements for characterizing optical fibers and how these requirements are met through appropriate data analysis and experimental apparatus design and implementation. To validate the developed methodology, the secondary objective of this research was to characterize both unperturbed and modified optical fibers. The RSD and the RID were measured in a standard telecommunications-grade optical fiber, Corning SMF-28. The effects of cleaving this fiber were also analyzed and the longitudinal variations that result from cleaving were explored for the first time. The fabrication of carbon-dioxide-laser-induced (CO2 -laser-induced) LPFGs was also examined. These devices provide many of the functionalities required for fiber-based communications components as well as fiber-based sensors, and they offer relaxed fabrication requirements when compared to LPFGs fabricated by other methods. The developed methodology was used to perform the first measurements of the changes that occur in the RSD and the RID during LPFG fabrication. The analysis of these measurements ties together many of the existing theories of CO2-laser-induced LPFG fabrication to present a more coherent understanding of the processes that occur. In addition, new evidence provides detailed information on the functional form of the RSD and the RID in LPFGs. This information is crucial for the modeling of LPFG behavior, for the design of LPFGs for specific applications, for the tailoring of fabrication parameters to meet design requirements, and for understanding the limitations of LPFG fabrication in commercial optical fibers. Future areas of research concerning the improvement of the developed methodology, the need to characterize other fibers and fiber-based devices, and the characterization of CO2-laser-induced LPFGs are identified and discussed.

Fiber optic laser-induced breakdown spectroscopy sensor for molten material analysis

DOEpatents

Zhang, Hansheng; Rai, Awadesh K.; Singh, Jagdish P.; Yueh, Fang-Yu

2004-07-13

A fiber optic laser-induced breakdown spectroscopy (LIBS) sensor, including a laser light source, a harmonic separator for directing the laser light, a dichroic mirror for reflecting the laser light, a coupling lens for coupling the laser light at an input of a multimode optical fiber, a connector for coupling the laser light from an output of the multimode optical fiber to an input of a high temperature holder, such as a holder made of stainless steel, and a detector portion for receiving emission signal and analyzing LIBS intensities. In one variation, the multimode optical fiber has silica core and silica cladding. The holder includes optical lenses for collimating and focusing the laser light in a molten alloy to produce a plasma, and for collecting and transmitting an emission signal to the multimode optical fiber.

Measurement of large strains in ropes using plastic optical fibers

DOEpatents

Williams, Jerry Gene; Smith, David Barton; Muhs, Jeffrey David

2006-02-14

A method for the direct measurement of large strains in ropes in situ using a plastic optical fiber, for example, perfluorocarbon or polymethyl methacrylate and Optical Time-Domain Reflectometer or other light time-of-flight measurement instrumentation. Protective sheaths and guides are incorporated to protect the plastic optical fiber. In one embodiment, a small rope is braided around the plastic optical fiber to impose lateral compressive forces to restrain the plastic optical fiber from slipping and thus experience the same strain as the rope. Methods are described for making reflective interfaces along the length of the plastic optical fiber and to provide the capability to measure strain within discrete segments of the rope. Interpretation of the data allows one to calculate the accumulated strain at any point in time and to determine if the rope has experienced local damage.

Miniature ball-tip optical fibers for use in thulium fiber laser ablation of kidney stones

NASA Astrophysics Data System (ADS)

Wilson, Christopher R.; Hardy, Luke A.; Kennedy, Joshua D.; Irby, Pierce B.; Fried, Nathaniel M.

2016-01-01

Optical fibers, consisting of 240-μm-core trunk fibers with rounded, 450-μm-diameter ball tips, are currently used during Holmium:YAG laser lithotripsy to reduce mechanical damage to the inner lining of the ureteroscope working channel during fiber insertion and prolong ureteroscope lifetime. Similarly, this study tests a smaller, 100-μm-core fiber with 300-μm-diameter ball tip during thulium fiber laser (TFL) lithotripsy. TFL was operated at a wavelength of 1908 nm, with 35-mJ pulse energy, 500-μs pulse duration, and 300-Hz pulse rate. Calcium oxalate/phosphate stone samples were weighed, laser procedure times were measured, and ablation rates were calculated for ball tip fibers, with comparison to bare tip fibers. Photographs of ball tips were taken before and after each procedure to track ball tip degradation and determine number of procedures completed before need for replacement. A high speed camera also recorded the cavitation bubble dynamics during TFL lithotripsy. Additionally, saline irrigation rates and ureteroscope deflection were measured with and without the presence of TFL fiber. There was no statistical difference (P>0.05) between stone ablation rates for single-use ball tip fiber (1.3±0.4 mg/s) (n=10), multiple-use ball tip fiber (1.3±0.5 mg/s) (n=44), and conventional single-use bare tip fibers (1.3±0.2 mg/s) (n=10). Ball tip durability varied widely, but fibers averaged greater than four stone procedures before failure, defined by rapid decline in stone ablation rates. Mechanical damage at the front surface of the ball tip was the limiting factor in fiber lifetime. The small fiber diameter did not significantly impact ureteroscope deflection or saline flow rates. The miniature ball tip fiber may provide a cost-effective design for safe fiber insertion through the ureteroscope working channel and into the ureter without risk of instrument damage or tissue perforation, and without compromising stone ablation efficiency during TFL lithotripsy.

The Fiber Optic Connection.

ERIC Educational Resources Information Center

Reese, Susan

2003-01-01

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

Method and device for detecting impact events on a security barrier which includes a hollow rebar allowing insertion and removal of an optical fiber

DOEpatents

Pies, Ross E.

2016-03-29

A method and device for the detection of impact events on a security barrier. A hollow rebar is farmed within a security barrier, whereby the hollow rebar is completely surrounded by the security barrier. An optical fiber passes through the interior of the hollow rebar. An optical transmitter and an optical receiver are both optically connected to the optical fiber and connected to optical electronics. The optical electronics are configured to provide notification upon the detection of an impact event at the security barrier based on the detection of disturbances within the optical fiber.

Optical system components for navigation grade fiber optic gyroscopes

NASA Astrophysics Data System (ADS)

Heimann, Marcus; Liesegang, Maximilian; Arndt-Staufenbiel, Norbert; Schröder, Henning; Lang, Klaus-Dieter

2013-10-01

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 change is introduced. A simplified 3 dimensional FEM of a quadrupole wound fiber coil is used to determine the build-up of thermal fields in the polarization maintaining fiber due to outside heating sources. The rotation rate error due to these sources is then calculated and compared to measurement data. A simple regression model is used to compensate the rotation rate error with temperature measurement at the outside of the fiber coil. To realize a compact and robust optical package for some of the relevant optical system components an approach based on ion exchanged waveguides in thin glass was developed. This waveguides are used to realize 1x2 and 1x4 splitter with fiber coupling interface or direct photodiode coupling.

Fiber Optic-Based Refractive Index Sensing at INESC Porto

PubMed Central

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

2012-01-01

A review of refractive index measurement based on different types of optical fiber sensor configurations and techniques is presented. It addresses the main developments in the area, with particular focus on results obtained at INESC Porto, Portugal. The optical fiber sensing structures studied include those based on Bragg and long period gratings, on micro-interferometers, on plasmonic effects in fibers and on multimode interference in a large spectrum of standard and microstructured optical fibers. PMID:22969405

Utilization of Infrared Fiber Optic in the Automotive Industry

NASA Technical Reports Server (NTRS)

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

2001-01-01

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

Bidirectional fiber-IVLLC and fiber-wireless convergence system with two orthogonally polarized optical sidebands.

PubMed

Lu, Hai-Han; Wu, Hsiao-Wen; Li, Chung-Yi; Ho, Chun-Ming; Yang, Zih-Yi; Cheng, Ming-Te; Lu, Chang-Kai

2017-05-01

A bidirectional fiber-invisible laser light communication (IVLLC) and fiber-wireless convergence system with two orthogonally polarized optical sidebands for hybrid cable television (CATV)/millimeter-wave (MMW)/baseband (BB) signal transmission is proposed and experimentally demonstrated. Two optical sidebands generated by a 60-GHz MMW signal are orthogonally polarized and separated into different polarizations. These orthogonally polarized optical sidebands are delivered over a 40-km single-mode fiber (SMF) transport to effectually reduce the fiber dispersion induced by a 40-km SMF transmission and the distortion caused by the parallel polarized optical sidebands. To the best of our knowledge, this work is the first to adopt two orthogonally polarized optical sidebands in a bidirectional fiber-IVLLC and fiber-wireless convergence system to reduce fiber dispersion and distortion effectually. Good carrier-to-noise ratio, composite second order, composite triple beat, and bit error rate (BER) are achieved for downlink transmission at a 40-km SMF operation and a 100-m free-space optical (FSO) link/3-m RF wireless transmission. For up-link transmission, good BER performance is acquired over a 40-km SMF transport and a 100-m FSO link. The approach presented in this work signifies the advancements in the convergence of SMF-based backbone and optical/RF wireless-based feeder.

System for determining position of normal shock in supersonic flow

NASA Technical Reports Server (NTRS)

Iverson, Jr., Donald G. (Inventor); Daiber, Troy D. (Inventor)

1991-01-01

Light from a plurality of light emitting diodes is transmitted through optical cables (12) to a lens system. The lenses (56, 58) expand and collimate the light and project it in a sheet (16) across the supersonic inlet of an aircraft power plant perpendicular to incoming airflow. A normal shock bends a portion of the sheet of light (16). A linear array of a multiplicity of optical fiber ends collects discrete samples of light. The samples are processed and compared to a predetermined profile to determine the shock location.

Nano-stepper-driven optical shutter for applications in free-space micro-optics

NASA Astrophysics Data System (ADS)

Zawadzka, Justyna; Li, Lijie; Unamuno, Anartz; Uttamchandani, Deepak G.

2002-09-01

In this paper we report a simple design of a micro-optical shutter/attenuator. The standard MUMPS process was used to fabricate the device. A vertically erected, gold-coated, 200x300 mm side length micro-mirror was precisely placed between the end faces of two closely spaced optical fibers. The position of the micro-mirror with respect to the optical fiber end face was controlled by a nano-stepping motor array. Optical and mechanical tests were performed on the device. A 1.55 mm laser beam was sent along the optical fiber. When the micro-mirror was removed from the front of the fiber, the coupling efficiency between two fibers was -10 dBm. Once the micro-mirror was placed in the optical path the coupling efficiency dropped to -51.5 dBm. The best attenuation was obtained when the micro-mirror blocked the whole cross-section of the laser beam diameter. It is evident that the device can operate as a high precision fiber optic attenuator or shutter.

Distributed Fiber-Optic Sensors for Vibration Detection

PubMed Central

Liu, Xin; Jin, Baoquan; Bai, Qing; Wang, Yu; Wang, Dong; Wang, Yuncai

2016-01-01

Distributed fiber-optic vibration sensors receive extensive investigation and play a significant role in the sensor panorama. Optical parameters such as light intensity, phase, polarization state, or light frequency will change when external vibration is applied on the sensing fiber. In this paper, various technologies of distributed fiber-optic vibration sensing are reviewed, from interferometric sensing technology, such as Sagnac, Mach–Zehnder, and Michelson, to backscattering-based sensing technology, such as phase-sensitive optical time domain reflectometer, polarization-optical time domain reflectometer, optical frequency domain reflectometer, as well as some combinations of interferometric and backscattering-based techniques. Their operation principles are presented and recent research efforts are also included. Finally, the applications of distributed fiber-optic vibration sensors are summarized, which mainly include structural health monitoring and perimeter security, etc. Overall, distributed fiber-optic vibration sensors possess the advantages of large-scale monitoring, good concealment, excellent flexibility, and immunity to electromagnetic interference, and thus show considerable potential for a variety of practical applications. PMID:27472334

Distributed Fiber-Optic Sensors for Vibration Detection.

PubMed

Liu, Xin; Jin, Baoquan; Bai, Qing; Wang, Yu; Wang, Dong; Wang, Yuncai

2016-07-26

Distributed fiber-optic vibration sensors receive extensive investigation and play a significant role in the sensor panorama. Optical parameters such as light intensity, phase, polarization state, or light frequency will change when external vibration is applied on the sensing fiber. In this paper, various technologies of distributed fiber-optic vibration sensing are reviewed, from interferometric sensing technology, such as Sagnac, Mach-Zehnder, and Michelson, to backscattering-based sensing technology, such as phase-sensitive optical time domain reflectometer, polarization-optical time domain reflectometer, optical frequency domain reflectometer, as well as some combinations of interferometric and backscattering-based techniques. Their operation principles are presented and recent research efforts are also included. Finally, the applications of distributed fiber-optic vibration sensors are summarized, which mainly include structural health monitoring and perimeter security, etc. Overall, distributed fiber-optic vibration sensors possess the advantages of large-scale monitoring, good concealment, excellent flexibility, and immunity to electromagnetic interference, and thus show considerable potential for a variety of practical applications.

Combined electromechanical impedance and fiber optic diagnosis of aerospace structures

NASA Astrophysics Data System (ADS)

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

2014-03-01

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

Highly Sensitive and Wide-Dynamic-Range Multichannel Optical-Fiber pH Sensor Based on PWM Technique.

PubMed

Khan, Md Rajibur Rahaman; Kang, Shin-Won

2016-11-09

In this study, we propose a highly sensitive multichannel pH sensor that is based on an optical-fiber pulse width modulation (PWM) technique. According to the optical-fiber PWM method, the received sensing signal's pulse width changes when the optical-fiber pH sensing-element of the array comes into contact with pH buffer solutions. The proposed optical-fiber PWM pH-sensing system offers a linear sensing response over a wide range of pH values from 2 to 12, with a high pH-sensing ability. The sensitivity of the proposed pH sensor is 0.46 µs/pH, and the correlation coefficient R² is approximately 0.997. Additional advantages of the proposed optical-fiber PWM pH sensor include a short/fast response-time of about 8 s, good reproducibility properties with a relative standard deviation (RSD) of about 0.019, easy fabrication, low cost, small size, reusability of the optical-fiber sensing-element, and the capability of remote sensing. Finally, the performance of the proposed PWM pH sensor was compared with that of potentiometric, optical-fiber modal interferometer, and optical-fiber Fabry-Perot interferometer pH sensors with respect to dynamic range width, linearity as well as response and recovery times. We observed that the proposed sensing systems have better sensing abilities than the above-mentioned pH sensors.

Highly Sensitive and Wide-Dynamic-Range Multichannel Optical-Fiber pH Sensor Based on PWM Technique

PubMed Central

Khan, Md. Rajibur Rahaman; Kang, Shin-Won

2016-01-01

In this study, we propose a highly sensitive multichannel pH sensor that is based on an optical-fiber pulse width modulation (PWM) technique. According to the optical-fiber PWM method, the received sensing signal’s pulse width changes when the optical-fiber pH sensing-element of the array comes into contact with pH buffer solutions. The proposed optical-fiber PWM pH-sensing system offers a linear sensing response over a wide range of pH values from 2 to 12, with a high pH-sensing ability. The sensitivity of the proposed pH sensor is 0.46 µs/pH, and the correlation coefficient R2 is approximately 0.997. Additional advantages of the proposed optical-fiber PWM pH sensor include a short/fast response-time of about 8 s, good reproducibility properties with a relative standard deviation (RSD) of about 0.019, easy fabrication, low cost, small size, reusability of the optical-fiber sensing-element, and the capability of remote sensing. Finally, the performance of the proposed PWM pH sensor was compared with that of potentiometric, optical-fiber modal interferometer, and optical-fiber Fabry–Perot interferometer pH sensors with respect to dynamic range width, linearity as well as response and recovery times. We observed that the proposed sensing systems have better sensing abilities than the above-mentioned pH sensors. PMID:27834865

Wideband fiber optic communications link

NASA Astrophysics Data System (ADS)

Bray, J. R.

1984-12-01

This thesis examined the feasibility of upgrading a nine port fiber optic bundle telecommunications system to a single strand fiber optic system. Usable pieces of equipment were identified and new Light Emitting Diodes (LED), Photodetectors and single strand SMA styled fiber optic connectors were ordered. Background research was conducted in the area of fiber optic power launching, fiber losses, connector losses and efficiencies. A new modulation/demodulation circuit was designed and constructed using parts from unused equipment. A new front panel was constructed to house the components, switches and connectors. A 2-m piece of optical fiber was terminated with the new connectors and tested for connector loss, numeric aperture and attenuation. The new LED was characterized by its emission radiation pattern and the entire system was tested for functional operation, frequency response and bandwidth of operation. An operations manual was prepared to ensure proper use in the future. The result was a two piece, single strand, fiber optic communications systems fully TTL compatible, capable of transmitting digital signals from 80 Kbit/sec to 20 Mbit/sec. The system was tested in a half duplex mode using both baseband and carrier modulated signals.

Raman fiber optic probe assembly for use in hostile environments

DOEpatents

Schmucker, John E.; Falk, Jon C.; Archer, William B.; Blasi, Raymond J.

2000-01-01

This invention provides a device for Raman spectroscopic measurement of composition and concentrations in a hostile environment by the use of a first fiber optic as a means of directing high intensity monochromatic light from a laser to the hostile environment and a second fiber optic to receive the lower intensity scattered light for transmittal to a monochromator for analysis. To avoid damage to the fiber optics, they are protected from the hostile environment. A preferred embodiment of the Raman fiber optic probe is able to obtain Raman spectra of corrosive gases and solutions at temperatures up to 600.degree. F. and pressures up to 2000 psi. The incident exciting fiber optic cable makes an angle of substantially 90.degree. with the collecting fiber optic cable. This 90.degree. geometry minimizes the Rayleigh scattering signal picked up by the collecting fiber, because the intensity of Rayleigh scattering is lowest in the direction perpendicular to the beam path of the exciting light and therefore a 90.degree. scattering geometry optimizes the signal to noise ratio.

Study of interface influence on bending performance of CFRP with embedded optical fibers

NASA Astrophysics Data System (ADS)

Liu, Rong-mei; Liang, Da-kai

2008-11-01

Studies showed that the bending strength of composite would be affected by embedded optical fibers. Interface strength between the embedded optical fiber and the matrix was studied in this paper. Based on the single fiber pull out tests, the interfacial shear strength between the coating and the clad is the weakest. The shear strength of the optical fiber used in this study is near to 0.8MPa. In order to study the interfacial effect on bending property of generic smart structure, a quasi-isotropic composite laminates were produced from Toray T300C/ epoxy prepreg. Optical fibers were embedded within different orientation plies of the plates, with the optical fibers embedded in the same direction. Accordingly, five different types of plates were produced. Impact tests were carried out on the 5 different plate types. It is shown that when the fiber was embedded at the upper layer, the bending strength drops mostly. The bending normal stress on material arrives at the maximum. So does the normal stress applied on the optical fiber at the surface. Therefore, destructions could originate at the interface between the coating and the clad foremost. The ultimate strength of the smart structure will be affected furthest.

System for testing optical fibers

DOEpatents

Golob, John E. [Olathe, KS; Looney, Larry D. [Los Alamos, NM; Lyons, Peter B. [Los Alamos, NM; Nelson, Melvin A. [Santa Barbara, CA; Davies, Terence J. [Santa Barbara, CA

1980-07-15

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