Embedded calibration system for the DIII-D Langmuir probe analog fiber optic links

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

Watkins, J. G.; Rajpal, R.; Mandaliya, H.

2012-10-15

This paper describes a generally applicable technique for simultaneously measuring offset and gain of 64 analog fiber optic data links used for the DIII-D fixed Langmuir probes by embedding a reference voltage waveform in the optical transmitted signal before every tokamak shot. The calibrated data channels allow calibration of the power supply control fiber optic links as well. The array of fiber optic links and the embedded calibration system described here makes possible the use of superior modern data acquisition electronics in the control room.

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.

Architecture for fiber-optic sensors and actuators in aircraft propulsion systems

NASA Technical Reports Server (NTRS)

Glomb, W. L., Jr.

1990-01-01

This paper describes a design for fiber-optic sensing and control in advanced aircraft Electronic Engine Control (EEC). The recommended architecture is an on-engine EEC which contains electro-optic interface circuits for fiber-optic sensors. Size and weight are reduced by multiplexing arrays of functionally similar sensors on a pairs of optical fibers to common electro-optical interfaces. The architecture contains interfaces to seven sensor groups. Nine distinct fiber-optic sensor types were found to provide the sensing functions. Analysis revealed no strong discriminator (except reliability of laser diodes and remote electronics) on which to base a selection of preferred common interface type. A hardware test program is recommended to assess the relative maturity of the technologies and to determine real performance in the engine environment.

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.

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

NASA Technical Reports Server (NTRS)

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

2008-01-01

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

Photonic Lantern Adaptive Spatial Mode Control in LMA Fiber Amplifiers using SPGD

DTIC Science & Technology

2015-12-15

ll.mit.edu Abstract: We demonstrate adaptive-spatial mode control (ASMC) in few- moded double- clad large mode area (LMA) fiber amplifiers by using an...combination resulting in a single fundamental mode at the output is achieved. 2015 Optical Society of America OCIS codes: (140.3510) Lasers ...fiber; (140.3425) Laser stabilization; (060.2340) Fiber optics components; (110.1080) Active or adaptive optics; References and links 1. C

Multiple-Ring Digital Communication Network

NASA Technical Reports Server (NTRS)

Kirkham, Harold

1992-01-01

Optical-fiber digital communication network to support data-acquisition and control functions of electric-power-distribution networks. Optical-fiber links of communication network follow power-distribution routes. Since fiber crosses open power switches, communication network includes multiple interconnected loops with occasional spurs. At each intersection node is needed. Nodes of communication network include power-distribution substations and power-controlling units. In addition to serving data acquisition and control functions, each node acts as repeater, passing on messages to next node(s). Multiple-ring communication network operates on new AbNET protocol and features fiber-optic communication.

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.

Optical technology for flight control systems

NASA Technical Reports Server (NTRS)

Mayanagi, M.

1986-01-01

Optical applications to the flight control system including optical data bus, sensors, and transducers are analyzed. Examples of optical data bus include airborne light optical fiber technology (ALOFT), F-5E, YA-7D, MIL-STD-1553 fiber optic data bus and NAL-optic data bus. This NAL-optic data bus is applied to STOL, and its characteristics are stressed. Principles and advantages of optical pulse-digital transducers are discussed.

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.

Process control using fiber optics and Fourier transform infrared spectroscopy

NASA Astrophysics Data System (ADS)

Kemsley, E. K.; Wilson, Reginald H.

1992-03-01

A process control system has been constructed using optical fibers interfaced to a Fourier transform infrared (FT-IR) spectrometer, to achieve remote spectroscopic analysis of food samples during processing. The multichannel interface accommodates six fibers, allowing the sequential observation of up to six samples. Novel fiber-optic sampling cells have been constructed, including transmission and attenuated total reflectance (ATR) designs. Different fiber types have been evaluated; in particular, plastic clad silica (PCS) and zirconium fluoride fibers. Processes investigated have included the dilution of fruit juice concentrate, and the addition of alcohol to fruit syrup. Suitable algorithms have been written which use the results of spectroscopic measurements to control and monitor the course of each process, by actuating devices such as valves and switches.

Femtosecond laser inscription of asymmetric directional couplers for in-fiber optical taps and fiber cladding photonics.

PubMed

Grenier, Jason R; Fernandes, Luís A; Herman, Peter R

2015-06-29

Precise alignment of femtosecond laser tracks in standard single mode optical fiber is shown to enable controllable optical tapping of the fiber core waveguide light with fiber cladding photonic circuits. Asymmetric directional couplers are presented with tunable coupling ratios up to 62% and bandwidths up to 300 nm at telecommunication wavelengths. Real-time fiber monitoring during laser writing permitted a means of controlling the coupler length to compensate for micron-scale alignment errors and to facilitate tailored design of coupling ratio, spectral bandwidth and polarization properties. Laser induced waveguide birefringence was harnessed for polarization dependent coupling that led to the formation of in-fiber polarization-selective taps with 32 dB extinction ratio. This technology enables the interconnection of light propagating in pre-existing waveguides with laser-formed devices, thereby opening a new practical direction for the three-dimensional integration of optical devices in the cladding of optical fibers and planar lightwave circuits.

Fiber-Coupled Acousto-Optical-Filter Spectrometer

NASA Technical Reports Server (NTRS)

Levin, Kenneth H.; Li, Frank Yanan

1993-01-01

Fiber-coupled acousto-optical-filter spectrometer steps rapidly through commanded sequence of wavelengths. Sample cell located remotely from monochromator and associated electronic circuitry, connected to them with optical fibers. Optical-fiber coupling makes possible to monitor samples in remote, hazardous, or confined locations. Advantages include compactness, speed, and no moving parts. Potential applications include control of chemical processes, medical diagnoses, spectral imaging, and sampling of atmospheres.

Fiber optics for aircraft engine/inlet control

NASA Technical Reports Server (NTRS)

Baumbick, R. J.

1981-01-01

NASA programs that focus on the use of fiber optics for aircraft engine/inlet control are reviewed. Fiber optics for aircraft control is attractive because of its inherent immunity to EMI and RFI noise. Optical signals can be safely transmitted through areas that contain flammable or explosive materials. The use of optics also makes remote sensing feasible by eliminating the need for electrical wires to be connected between sensors and computers. Using low-level optical signals to control actuators is also feasible when power is generated at the actuator. Each application of fiber optics for aircraft control has different requirements for both the optical cables and the optical connectors. Sensors that measure position and speed by using slotted plates can use lossy cables and bundle connectors if data transfer is in the parallel mode. If position and speed signals are multiplexed, cable and connector requirements change. Other sensors that depend on changes in transmission through materials require dependable characteristics of both the optical cables and the optical connectors. A variety of sensor types are reviewed, including rotary position encoders, tachometers, temperature sensors, and blade tip clearance sensors for compressors and turbines. Research on a gallium arsenide photoswitch for optically switched actuators that operate at 250 C is also described.

Single-Fiber Optical Link For Video And Control

NASA Technical Reports Server (NTRS)

Galloway, F. Houston

1993-01-01

Single optical fiber carries control signals to remote television cameras and video signals from cameras. Fiber replaces multiconductor copper cable, with consequent reduction in size. Repeaters not needed. System works with either multimode- or single-mode fiber types. Nonmetallic fiber provides immunity to electromagnetic interference at suboptical frequencies and much less vulnerable to electronic eavesdropping and lightning strikes. Multigigahertz bandwidth more than adequate for high-resolution television signals.

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.

Bright and dark solitons in the normal dispersion regime of inhomogeneous optical fibers: Soliton interaction and soliton control

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

Liu Wenjun; Tian Bo, E-mail: tian.bupt@yahoo.com.c; State Key Laboratory of Software Development Environment, Beijing University of Aeronautics and Astronautics, Beijing 100191

2010-08-15

Symbolically investigated in this paper is a nonlinear Schroedinger equation with the varying dispersion and nonlinearity for the propagation of optical pulses in the normal dispersion regime of inhomogeneous optical fibers. With the aid of the Hirota method, analytic one- and two-soliton solutions are obtained. Relevant properties of physical and optical interest are illustrated. Different from the previous results, both the bright and dark solitons are hereby derived in the normal dispersion regime of the inhomogeneous optical fibers. Moreover, different dispersion profiles of the dispersion-decreasing fibers can be used to realize the soliton control. Finally, soliton interaction is discussed withmore » the soliton control confirmed to have no influence on the interaction. The results might be of certain value for the study of the signal generator and soliton control.« less

Mode-Selective Amplification in a Large Mode Area Yb-Doped Fiber Using a Photonic Lantern

DTIC Science & Technology

2016-05-15

in a few mode, double- clad Yb-doped large mode area (LMA) fiber, utilizing an all-fiber photonic lantern. Amplification to multi-watt output power is...that could enable dynamic spatial mode control in high power fiber lasers . © 2016 Optical Society of America OCIS codes: (060.2320) Fiber optics...amplifiers and oscillators; (060.2340) Fiber optics components. http://dx.doi.org/10.1364/OL.41.002157 The impressive growth experienced by fiber lasers and

Demonstration of pulse controlled all-optical switch/modulator.

PubMed

Akin, Osman; Dinleyici, M S

2014-03-15

An all-optical pulse controlled switch/modulator based on evanescent coupling between a polymer slab waveguide and a single mode fiber is demonstrated. Very fast all-optical modulation/switching is achieved via Kerr effect of the nonlinear polymer placed in the evanescent region of the optical fiber. Local refractive index perturbation (Δn=-1.45612×10(-5)) on the thin film leads to 0.374 nW power modulation at the fiber output, which results in a switching efficiency of ≈1.5%.

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.

Ultrafast optics. Ultrafast optical control by few photons in engineered fiber.

PubMed

Nissim, R; Pejkic, A; Myslivets, E; Kuo, B P; Alic, N; Radic, S

2014-07-25

Fast control of a strong optical beam by a few photons is an outstanding challenge that limits the performance of quantum sensors and optical processing devices. We report that a fast and efficient optical gate can be realized in an optical fiber that has been engineered with molecular-scale accuracy. Highly efficient, distributed phase-matched photon-photon interaction was achieved in the fiber with locally controlled, nanometer-scale core variations. A three-photon input was used to manipulate a Watt-scale beam at a speed exceeding 500 gigahertz. In addition to very fast beam control, the results provide a path to developing a new class of sensitive receivers capable of operating at very high rates. Copyright © 2014, American Association for the Advancement of Science.

Use of visible-laser-diode fiber optic sensors in the beverage industry and environmental controls

NASA Astrophysics Data System (ADS)

Pham, Van Hoi; Chu, Dinh T.; Bui, Huy; Tran, Viet L.

1997-01-01

The fiber-optic refractometer using visible laser diodes with wavelengths of 650 divided by 670 nm for the liquid refractive-index measurement is presented. The refractive- index measures by fiber-optic sensors of the connected configuration for different liquids with refractive indices from 1.33 to 1.5 have given the accuracy of 5.10-3. The fiber-optic refractometer was performanced for the distinguish of the salt or sugar content in the mixtures with range of 10-3 and 5.10-4, respectively. These refractometers are already to use for the sugar control systems of beverage industry and salt-water environment.

Spectrum-Modulating Fiber-Optic Sensors

NASA Technical Reports Server (NTRS)

Beheim, Glenn; Fritsch, Klaus

1989-01-01

Family of spectrum-modulating fiber-optic sensors undergoing development for use in aircraft-engine control systems. Fiber-optic sensors offer advantages of small size, high bandwidth, immunity to electromagnetic interference, and light weight. Furthermore, they reduce number of locations on aircraft to which electrical power has to be supplied.

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.

Evaluation of the Use of Optical Fiber Thermometers for Thermal Control of the Quench Module Insert

NASA Technical Reports Server (NTRS)

Jones, Matthew R.; Farmer, Jeffrey T.; Breeding, Shawn P.

2001-01-01

Issues regarding the use of optical fiber thermometers to control heater settings in a microgravity vacuum furnace are addressed. It is desirable to use these probes in environments such as the International Space Station, because they can be operated without re-calibration for extended periods. However, the analysis presented in this paper shows that temperature readings obtained using optical fiber thermometers can be corrupted by emissions from the fiber when extended portions of the probe are exposed to elevated temperatures.

Evaluation of the Use of Optical Fiber Thermometers for Thermal Control of the Quench Module Insert

NASA Technical Reports Server (NTRS)

Jones, Matthew R.; Farmer, Jeffrey T.; Breeding, Shawn P.

1999-01-01

Issues regarding the use of optical fiber thermometers to control heater settings in a microgravity vacuum furnace are addressed. It is desirable to use these probes in environments such as the International Space Station, because they can be operated without re-calibration for extended periods. However, the analysis presented in this paper shows that temperature readings obtained using optical fiber thermometers are corrupted due to emissions from the fiber when extended portions of the probe are exposed to elevated temperatures.

Optical fiber sensors and signal processing for intelligent structure monitoring

NASA Technical Reports Server (NTRS)

Rogowski, Robert; Claus, R. O.; Lindner, D. K.; Thomas, Daniel; Cox, Dave

1988-01-01

The analytic and experimental performance of optical fiber sensors for the control of vibration of large aerospace and other structures are investigated. In particular, model domain optical fiber sensor systems, are being studied due to their apparent potential as distributed, low mass sensors of vibration over appropriate ranges of both low frequency and low amplitude displacements. Progress during the past three months is outlined. Progress since September is divided into work in the areas of experimental hardware development, analytical analysis, control design and sensor development. During the next six months, tests of a prototype closed-loop control system for a beam are planned which will demonstrate the solution of several optical fiber instrumentation device problems, the performance of the control system theory which incorporates the model of the modal domain sensor, and the potential for distributed control which this sensor approach offers.

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.

Broadband single-mode operation of standard optical fibers by using a sub-wavelength optical wire filter.

PubMed

Jung, Yongmin; Brambilla, Gilberto; Richardson, David J

2008-09-15

We report the use of a sub-wavelength optical wire (SOW) with a specifically designed transition region as an efficient tool to filter higher-order modes in multimode waveguides. Higher-order modes are effectively suppressed by controlling the transition taper profile and the diameter of the sub-wavelength optical wire. As a practical example, single-mode operation of a standard telecom optical fiber over a broad spectral window (400 approximately 1700 nm) was demonstrated with a 1microm SOW. The ability to obtain robust and stable single-mode operation over a very broad range of wavelengths offers new possibilities for mode control within fiber devices and is relevant to a range of application sectors including high performance fiber lasers, sensors, photolithography, and optical coherence tomography systems.

The LED and fiber based calibration system for the photomultiplier array of SNO+

NASA Astrophysics Data System (ADS)

Seabra, L.; Alves, R.; Andringa, S.; Bradbury, S.; Carvalho, J.; Clark, K.; Coulter, I.; Descamps, F.; Falk, L.; Gurriana, L.; Kraus, C.; Lefeuvre, G.; Maio, A.; Maneira, J.; Mottram, M.; Peeters, S.; Rose, J.; Sinclair, J.; Skensved, P.; Waterfield, J.; White, R.; Wilson, J.; SNO+ Collaboration

2015-02-01

A new external LED/fiber light injection calibration system was designed for the calibration and monitoring of the photomultiplier array of the SNO+ experiment at SNOLAB. The goal of the calibration system is to allow an accurate and regular measurement of the photomultiplier array's performance, while minimizing the risk of radioactivity ingress. The choice in SNO+ was to use a set of optical fiber cables to convey into the detector the light pulses produced by external LEDs. The quality control was carried out using a modified test bench that was used in QC of optical fibers for TileCal/ATLAS. The optical fibers were characterized for transmission, timing and angular dispersions. This article describes the setups used for the characterization and quality control of the system based on LEDs and optical fibers and their results.

Micro-controller based air pressure monitoring instrumentation system using optical fibers as sensor

NASA Astrophysics Data System (ADS)

Hazarika, D.; Pegu, D. S.

2013-03-01

This paper describes a micro-controller based instrumentation system to monitor air pressure using optical fiber sensors. The principle of macrobending is used to develop the sensor system. The instrumentation system consists of a laser source, a beam splitter, two multi mode optical fibers, two Light Dependent Resistance (LDR) based timer circuits and a AT89S8252 micro-controller. The beam splitter is used to divide the laser beam into two parts and then these two beams are launched into two multi mode fibers. One of the multi mode fibers is used as the sensor fiber and the other one is used as the reference fiber. The use of the reference fiber is to eliminate the environmental effects while measuring the air pressure magnitude. The laser beams from the sensor and reference fibers are applied to two identical LDR based timer circuits. The LDR based timer circuits are interfaced to a micro-controller through its counter pins. The micro-controller samples the frequencies of the timer circuits using its counter-0 and counter-1 and the counter values are then processed to provide the measure of air pressure magnitude.

High-power fiber optic cable with integrated active sensors for live process monitoring

NASA Astrophysics Data System (ADS)

Blomster, Ola; Blomqvist, Mats; Bergstrand, Hans; Pålsson, Magnus

2012-03-01

In industrial applications using high-brilliance lasers at power levels up to and exceeding 20 kW and similarly direct diode lasers of 10 kW, there is an increasing demand to continuously monitor component status even in passive components such as fiber-optic cables. With fiber-optic cables designed according to the European Automotive Industry fiber standard interface there is room for integrating active sensors inside the connectors. In this paper we present the integrated active sensors in the new Optoskand QD fiber-optic cable designed to handle extreme levels of power losses, and how these sensors can be employed in industrial manufacturing. The sensors include photo diodes for detection of scattered light inside the fiber connector, absolute temperature of the fiber connector, difference in temperature of incoming and outgoing cooling water, and humidity measurement inside the fiber connector. All these sensors are connected to the fiber interlock system, where interlock break enable functions can be activated when measured signals are higher than threshold levels. It is a very fast interlock break system as the control of the signals is integrated in the electronics inside the fiber connector. Also, since all signals can be logged it is possible to evaluate what happened inside the connector before the interlock break instance. The communication to the fiber-optic connectors is via a CAN interface. Thus it is straightforward to develop the existing laser host control to also control the CAN-messages from the QD sensors.

Liquid crystal photonic bandgap fiber components

NASA Astrophysics Data System (ADS)

Scolari, L.; Alkeskjold, T. T.; Noordegraaf, D.; Tartarini, G.; Bassi, P.; Bjarklev, A.

2007-11-01

Liquid crystal photonic bandgap fibers represent a promising platform for the design of all-in-fiber optical devices, which show a high degree of tunability and exhibit novel optical properties for the manipulation of guided light. In this review paper we present tunable fiber devices for spectral filtering, such as Gaussian filters and notch filters, and devices for polarization control and analysis, such as birefringence control devices and switchable and rotatable polarizers.

Head-mounted LED for optogenetic experiments of freely-behaving animal

NASA Astrophysics Data System (ADS)

Kwon, Ki Yong; Gnade, Andrew G.; Rush, Alexander D.; Patten, Craig D.

2016-03-01

Recent developments in optogenetics have demonstrated the ability to target specific types of neurons with sub-millisecond temporal precision via direct optical stimulation of genetically modified neurons in the brain. In most applications, the beam of a laser is coupled to an optical fiber, which guides and delivers the optical power to the region of interest. Light emitting diodes (LEDs) are an alternative light source for optogenetics and they provide many advantages over a laser based system including cost, size, illumination stability, and fast modulation. Their compact size and low power consumption make LEDs suitable light sources for a wireless optogenetic stimulation system. However, the coupling efficiency of an LED's output light into an optical fiber is lower than a laser due to its noncollimated output light. In typical chronic optogenetic experiment, the output of the light source is transmitted to the brain through a patch cable and a fiber stub implant, and this configuration requires two fiber-to-fiber couplings. Attenuation within the patch cable is potential source of optical power loss. In this study, we report and characterize a recently developed light delivery method for freely-behaving animal experiments. We have developed a head-mounted light source that maximizes the coupling efficiency of an LED light source by eliminating the need for a fiber optic cable. This miniaturized LED is designed to couple directly to the fiber stub implant. Depending on the desired optical power output, the head-mounted LED can be controlled by either a tethered (high power) or battery-powered wireless (moderate power) controller. In the tethered system, the LED is controlled through 40 gauge micro coaxial cable which is thinner, more flexible, and more durable than a fiber optic cable. The battery-powered wireless system uses either infrared or radio frequency transmission to achieve real-time control. Optical, electrical, mechanical, and thermal characteristics of the head-mounted LED were evaluated.

Design of control system for optical fiber drawing machine driven by double motor

NASA Astrophysics Data System (ADS)

Yu, Yue Chen; Bo, Yu Ming; Wang, Jun

2018-01-01

Micro channel Plate (MCP) is a kind of large-area array electron multiplier with high two-dimensional spatial resolution, used as high-performance night vision intensifier. The high precision control of the fiber is the key technology of the micro channel plate manufacturing process, and it was achieved by the control of optical fiber drawing machine driven by dual-motor in this paper. First of all, utilizing STM32 chip, the servo motor drive and control circuit was designed to realize the dual motor synchronization. Secondly, neural network PID control algorithm was designed for controlling the fiber diameter fabricated in high precision; Finally, the hexagonal fiber was manufactured by this system and it shows that multifilament diameter accuracy of the fiber is +/- 1.5μm.

Fiber-Optic Distribution Of Pulsed Power To Multiple Sensors

NASA Technical Reports Server (NTRS)

Kirkham, Harold

1996-01-01

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

Manipulation of mammalian cells using a single-fiber optical microbeam

PubMed Central

Mohanty, Samarendra K.; Mohanty, Khyati S.; Berns, Michael W.

2014-01-01

The short working distance of microscope objectives has severely restricted the application of optical micromanipulation techniques at larger depths. We show the first use of fiber-optic tweezers toward controlled guidance of neuronal growth cones and stretching of neurons. Further, by mode locking, the fiber-optic tweezers beam was converted to fiber-optic scissors, enabling dissection of neuronal processes and thus allowing study of the subsequent response of neurons to localized injury. At high average powers, lysis of a three-dimensionally trapped cell was accomplished. PMID:19021429

Analysis of Photonic Phase-Shifting Technique Employing Amplitude-Controlled Fiber-Optic Delay Lines

DTIC Science & Technology

2012-01-13

Controlled Fiber-Optic Delay Lines January 13, 2012 Approved for public release; distribution is unlimited. Meredith N. draa ViNceNt J. Urick keith J...Draa, Vincent J. Urick , and Keith J. Williams Naval Research Laboratory, Code 5652 4555 Overlook Avenue, SW Washington, DC 20375-5320 NRL/MR/5650--12...9376 Approved for public release; distribution is unlimited. Unclassified Unclassified Unclassified UU 29 Vincent J. Urick (202) 767-9352 Fiber optics

Nonlinear waveguide optics and photonic crystal fibers.

PubMed

Knight, J C; Skryabin, D V

2007-11-12

Focus Serial: Frontiers of Nonlinear Optics

Controlled core removal from a D-shaped optical fiber.

PubMed

Markos, Douglas J; Ipson, Benjamin L; Smith, Kevin H; Schultz, Stephen M; Selfridge, Richard H; Monte, Thomas D; Dyott, Richard B; Miller, Gregory

2003-12-20

The partial removal of a section of the core from a continuous D-shaped optical fiber is presented. In the core removal process, selective chemical etching is used with hydrofluoric (HF) acid. A 25% HF acid solution removes the cladding material above the core, and a 5% HF acid solution removes the core. A red laser with a wavelength of 670 nm is transmitted through the optical fiber during the etching. The power transmitted through the optical fiber is correlated to the etch depth by scanning electron microscope imaging. The developed process provides a repeatable method to produce an optical fiber with a specific etch depth.

A Piezoelectroluminescent Fiber-Optical Sensor for Diagnostics of the 3D Stress State in Composite Structures

NASA Astrophysics Data System (ADS)

Pan'kov, A. A.

2018-05-01

The mathematical model of a piezoelectroluminescent fiber-optical sensor is developed for diagnostics of the 3D stress state of composite structures. The sensor model is a coaxial sector-compound layered cylinder consisting of a central optical fiber with electroluminescent and piezoelectric layers and an external uniform elastic buffer layer. The electroluminescent and piezoelectric layers are separated by radial-longitudinal boundaries, common for both layers, into geometrically equal six "measuring elements" — cylindrical two-layered sectors. The directions of 3D polarization of the piezoelectric phases and the frequencies of luminous efficacy of the electroluminescent phases are different in each sector. In the sensor, a thin translucent "internal" controlling electrode is located between the optical fiber and the electroluminescent layer, and the piezoelectric layer is coated by a thin "external" controlling electrode. The results of numerical modeling of the nonuniform coupled electroelastic fields of the piezoelectroluminescent fiber-optical sensor in the loaded "representative volume" of a composite, taking into account the action of the controlling voltage on the internal and external electrodes, of a numerical calculation of "informative and controlling coefficients" of the sensor, and of testing of an arbitrary 3D stress of state of a unidirectional glass-fiber plastic by the finite-element method are presented.

Phase shift of TE and TM modes in an optical fiber due to axial strain (exact solution)

NASA Technical Reports Server (NTRS)

Egalon, Claudio O.; Rogowski, Robert S.

1992-01-01

Axial strain may be determined by monitoring the phase shift of modes of a variety of optical fiber sensors. In this paper, the exact solution of a circular optical fiber is used to calculate the phase shift of the TE and TM modes. Whenever an optical fiber is stressed, the optical path length, the index of refraction, and the propagation constants of each fiber mode change. In consequence, the modal phase term, beta(ln)z, of the fields is shifted by an amount Delta phi. In certain cases, it is desirable to control the phase shift term in order to make the fiber either more or less sensitive to certain kinds of strain. It is shown that it can be accomplished by choosing appropriate fiber parameters.

Fiber optics for propulsion control systems

NASA Technical Reports Server (NTRS)

Baumbick, R. J.

1985-01-01

In aircraft systems with digital controls, fiberoptics has advantages over wire systems because of its inherent immunity to electromagnetic noise (EMI) and electromagnetic pulses (EMP). It also offers a weight benefit when metallic conductors are replaced by optical fibers. To take full advantage of the benefits of optical waveguides, passive optical sensors are also being developed to eliminate the need for electrical power to the sensor. Fiberoptics may also be used for controlling actuators on engine and airframe. In this application, the optical fibers, connectors, etc. will be subjected to high temperature and vibrations. This paper discussed the use of fiberoptics in aircraft propulsion systems together with the optical sensors and optically controlled actuators being developed to take full advantage of the benefits which fiberoptics offers. The requirements for sensors and actuators in advanced propulsion systems are identified. The benefits of using fiberoptics in place of conventional wire systems are discussed as well as the environmental conditions under which the optical components must operate.

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.

Microstructured Optical Fiber Sensors Embedded in a Laminate Composite for Smart Material Applications

PubMed Central

Sonnenfeld, Camille; Sulejmani, Sanne; Geernaert, Thomas; Eve, Sophie; Lammens, Nicolas; Luyckx, Geert; Voet, Eli; Degrieck, Joris; Urbanczyk, Waclaw; Mergo, Pawel; Becker, Martin; Bartelt, Hartmut; Berghmans, Francis; Thienpont, Hugo

2011-01-01

Fiber Bragg gratings written in highly birefringent microstructured optical fiber with a dedicated design are embedded in a composite fiber-reinforced polymer. The Bragg peak wavelength shifts are measured under controlled axial and transversal strain and during thermal cycling of the composite sample. We obtain a sensitivity to transversal strain that exceeds values reported earlier in literature by one order of magnitude. Our results evidence the relevance of using microstructured optical fibers for structural integrity monitoring of composite material structures. PMID:22163755

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.

Fabrication of Multi-point Side-Firing Optical Fiber by Laser Micro-ablation

PubMed Central

Nguyen, Hoang; Arnob, Md Masud Parvez; Becker, Aaron T; Wolfe, John C; Hogan, Matthew K; Horner, Philip J; Shih, Wei-Chuan

2018-01-01

A multi-point, side-firing design enables an optical fiber to output light at multiple desired locations along the fiber body. This provides advantages over traditional end-to-end fibers, especially in applications requiring fiber bundles such as brain stimulation or remote sensing. This paper demonstrates that continuous wave (CW) laser micro-ablation can controllably create conical-shaped cavities, or side windows, for outputting light. The dimensions of these cavities determine the amount of firing light and their firing angle. Experimental data show that a single side window on a 730 μm fiber can deliver more than 8 % of the input light. This was increased to more than 19 % on a 65 μm fiber with side windows created using femtosecond (fs) laser ablation and chemical etching. Fine control of light distribution along an optical fiber is critical for various biomedical applications such as light activated drug-release and optogenetics studies. PMID:28454166

Multipoint fiber-optic laser-ultrasonic actuator based on fiber core-opened tapers.

PubMed

Tian, Jiajun; Dong, Xiaolong; Gao, Shimin; Yao, Yong

2017-11-27

In this study, a novel fiber-optic, multipoint, laser-ultrasonic actuator based on fiber core-opened tapers (COTs) is proposed and demonstrated. The COTs were fabricated by splicing single-mode fibers using a standard fiber splicer. A COT can effectively couple part of a core mode into cladding modes, and the coupling ratio can be controlled by adjusting the taper length. Such characteristics are used to obtain a multipoint, laser-ultrasonic actuator with balanced signal strength by reasonably controlling the taper lengths of the COTs. As a prototype, we constructed an actuator that generated ultrasound at four points with a balanced ultrasonic strength by connecting four COTs with coupling ratios of 24.5%, 33.01%, 49.51%, and 87.8% in a fiber link. This simple-to-fabricate, multipoint, laser-ultrasonic actuator with balanced ultrasound signal strength has potential applications in fiber-optic ultrasound testing technology.

Fabrication of multipoint side-firing optical fiber by laser micro-ablation.

PubMed

Nguyen, Hoang; Parvez Arnob, Md Masud; Becker, Aaron T; Wolfe, John C; Hogan, Matthew K; Horner, Philip J; Shih, Wei-Chuan

2017-05-01

A multipoint, side-firing design enables an optical fiber to output light at multiple desired locations along the fiber body. This provides advantages over traditional end-to-end fibers, especially in applications requiring fiber bundles such as brain stimulation or remote sensing. This Letter demonstrates that continuous wave (CW) laser micro-ablation can controllably create conical-shaped cavities, or side windows, for outputting light. The dimensions of these cavities determine the amount of firing light and their firing angle. Experimental data show that a single side window on a 730 μm fiber can deliver more than 8% of the input light. This can be increased to more than 19% on a 65 μm fiber with side windows created using femtosecond laser ablation and chemical etching. Fine control of light distribution along an optical fiber is critical for various biomedical applications such as light-activated drug-release and optogenetics studies.

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.

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.

Fiber-optic projected-fringe digital interferometry

NASA Technical Reports Server (NTRS)

Mercer, Carolyn R.; Beheim, Glenn

1990-01-01

A phase-stepped projected-fringe interferometer was developed which uses a closed-loop fiber-optic phase-control system to make very accurate surface profile measurements. The closed-loop phase-control system greatly reduces phase-stepping error, which is frequently the dominant source of error in digital interferometers. Two beams emitted from a fiber-optic coupler are combined to form an interference fringe pattern on a diffusely reflecting object. Reflections off of the fibers' output faces are used to create a phase-indicating signal for the closed-loop optical phase controller. The controller steps the phase difference between the two beams by pi/2 radians in order to determine the object's surface profile using a solid-state camera and a computer. The system combines the ease of alignment and automated data reduction of phase-stepping projected-fringe interferometry with the greatly improved phase-stepping accuracy of our closed-loop phase-controller. The system is demonstrated by measuring the profile of a plate containing several convex surfaces whose heights range from 15 to 25 micron high.

Mode-selective mapping and control of vectorial nonlinear-optical processes in multimode photonic-crystal fibers.

PubMed

Hu, Ming-Lie; Wang, Ching-Yue; Song, You-Jian; Li, Yan-Feng; Chai, Lu; Serebryannikov, Evgenii; Zheltikov, Aleksei

2006-02-06

We demonstrate an experimental technique that allows a mapping of vectorial nonlinear-optical processes in multimode photonic-crystal fibers (PCFs). Spatial and polarization modes of PCFs are selectively excited in this technique by varying the tilt angle of the input beam and rotating the polarization of the input field. Intensity spectra of the PCF output plotted as a function of the input field power and polarization then yield mode-resolved maps of nonlinear-optical interactions in multimode PCFs, facilitating the analysis and control of nonlinear-optical transformations of ultrashort laser pulses in such fibers.

Acoustic waves in tilted fiber Bragg gratings for sensing applications

NASA Astrophysics Data System (ADS)

Marques, Carlos A. F.; Alberto, Nélia J.; Domingues, Fátima; Leitão, Cátia; Antunes, Paulo; Pinto, João. L.; André, Paulo

2017-05-01

Tilted fiber Bragg gratings (TFBGs) are one of the most attractive kind of optical fiber sensor technology due to their intrinsic properties. On the other hand, the acousto-optic effect is an important, fast and accurate mechanism that can be used to change and control several properties of fiber gratings in silica and polymer optical fiber. Several all-optical devices for optical communications and sensing have been successfully designed and constructed using this effect. In this work, we present the recent results regarding the production of optical sensors, through the acousto-optic effect in TFBGs. The cladding and core modes amplitude of a TFBG can be controlled by means of the power levels from acoustic wave source. Also, the cladding modes of a TFBG can be coupled back to the core mode by launching acoustic waves. Induced bands are created on the left side of the original Bragg wavelength due to phase matching to be satisfied. The refractive index (RI) is analyzed in detail when acoustic waves are turned on using saccharose solutions with different RI from 1.33 to 1.43.

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.

AVIRIS foreoptics, fiber optics and on-board calibrator

NASA Technical Reports Server (NTRS)

Chrisp, Michael P.; Chrien, Thomas G.; Steimle, L.

1987-01-01

The foreoptics, fiber optic system and calibration source of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) are described. The foreoptics, based on a modified Kennedy scanner, is coupled by optical fibers to the four spectrometers. The optical fibers allow convenient positioning of the spectrometers in the limited space and enable simple compensation of the scanner's thermal defocus (at the -23 C operating temp) by active control of the fiber focal plane position. A challenging requirement for the fiber optic system was the transmission to the spectral range 1.85 to 2.45 microns at .45 numerical aperture. This was solved with custom fluoride glass fibers from Verre Fluore. The onboard calibration source is also coupled to the spectrometers by the fibers and provides two radiometric levels and a reference spectrum to check the spectrometers' alignment. Results of the performance of the assembled subsystems are presented.

Exploiting solitons in all-optical networks

NASA Astrophysics Data System (ADS)

Atieh, Ahmad K.

Two key components, the pulse generator and optical signal demultiplexer, needed for the implementation of all-optical soliton-based local area and wide area networks are investigated. The technology of generating a bright soliton pulse train from a sinusoidal pulse train produced as the beat signal of two distributed feedback laser diodes passed through a so-called comblike fiber structure is developed. A design methodology for this structure is discussed, and using this approach a soliton pulse source is constructed generating 1553 nm pulses at a repetition rate of 50 GHz, with pulses of full width at half maximum of 2.0 ps. The fiber structure used to generate the bright soliton pulse train employs the lowest average power for the beat signal ever reported in the literature, and the shortest length of fiber. The same structure (with a different design) is also used to produce a 47.6 GHz dark soliton pulse train with a full width at half maximum of 3.8 ps. This is the first reported use of this structure to generate dark solitons. It is shown that the comblike dispersion profile fiber structures may also be exploited for soliton pulse compression producing widths as short as 200 fs. Two approaches to implementation of optical signal demultiplexing are discussed. These are the nonlinear optical loop mirror (NOLM) and the separation of multilevel time division multiplexed signal pulses in the frequency domain by exploiting the relationship between the pulse's energy (i.e. pulse amplitude and width) and the Raman self-frequency shift. A modification of the NOLM scheme is investigated where feedback that adjusts the power of the control signal (by controlling the gain of an erbium-doped fiber amplifier introduced into the control signal input path) is employed to make the structure insensitive to the state of polarization of the signal and control pulses. In order to better understand the physical phenomena exploited in optical fiber soliton transmission and the above schemes, two experiments are conducted to measure the fiber nonlinear ratio (n2/Aeff) and the Raman time constant (TR) in single-mode fibers at 1550 nm. The fiber nonlinear ratio was measured for standard telecommunication fiber, dispersion shifted fiber, and dispersion compensating fiber. A value of 3.0 fs for the Raman time constant was measured and is recommended for soliton pulse propagation modeling in single-mode optical fibers.

Designing optical-fiber modulators by using magnetic fluids.

PubMed

Horng, H E; Chieh, J J; Chao, Y H; Yang, S Y; Hong, Chin-Yih; Yang, H C

2005-03-01

To reduce interface loss between optical fibers and devices in telecommunication systems, the development of an optical-fiber-based device that can be fused directly with fibers is important. A novel optical modulator consisting of a bare fiber core surrounded by magnetic fluids instead of by a SiO2 cladding layer is proposed. Applying a magnetic field raises the refractive index of the magnetic fluid. Thus we can control the occurrence of total reflection at the interface between the fiber core and the magnetic fluid when light propagates along the fiber. As a result, the intensity of the outgoing light is modulated by variation in field strength. Details of the design, fabrication, and working properties of such a modulator are presented.

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.

A wide-band fiber optic frequency distribution system employing thermally controlled phase compensation

NASA Technical Reports Server (NTRS)

Johnson, Dean; Calhoun, Malcolm; Sydnor, Richard; Lutes, George

1993-01-01

An active wide-band fiber optic frequency distribution system employing a thermally controlled phase compensator to stabilize phase variations induced by environmental temperature changes is described. The distribution system utilizes bidirectional dual wavelength transmission to provide optical feedback of induced phase variations of 100 MHz signals propagating along the distribution cable. The phase compensation considered differs from earlier narrow-band phase compensation designs in that it uses a thermally controlled fiber delay coil rather than a VCO or phase modulation to compensate for induced phase variations. Two advantages of the wide-band system over earlier designs are (1) that it provides phase compensation for all transmitted frequencies, and (2) the compensation is applied after the optical interface rather than electronically ahead of it as in earlier schemes. Experimental results on the first prototype shows that the thermal stabilizer reduces phase variations and Allan deviation by a factor of forty over an equivalent uncompensated fiber optic distribution system.

Method and apparatus for shape and end position determination using an optical fiber

NASA Technical Reports Server (NTRS)

Moore, Jason P. (Inventor)

2010-01-01

A method of determining the shape of an unbound optical fiber includes collecting strain data along a length of the fiber, calculating curvature and bending direction data of the fiber using the strain data, curve-fitting the curvature and bending direction data to derive curvature and bending direction functions, calculating a torsion function using the bending direction function, and determining the 3D shape from the curvature, bending direction, and torsion functions. An apparatus for determining the 3D shape of the fiber includes a fiber optic cable unbound with respect to a protective sleeve, strain sensors positioned along the cable, and a controller in communication with the sensors. The controller has an algorithm for determining a 3D shape and end position of the fiber by calculating a set of curvature and bending direction data, deriving curvature, bending, and torsion functions, and solving Frenet-Serret equations using these functions.

Control systems using modal domain optical fiber sensors for smart structure applications

NASA Technical Reports Server (NTRS)

Lindner, Douglas K.; Reichard, Karl M.

1991-01-01

Recently, a new class of sensors has emerged for structural control which respond to environmental changes over a significant gauge length; these sensors are called distributed-effect sensors. These sensors can be fabricated with spatially varying sensitivity to the distributed measurand, and can be configured to measure a variety of structural parameters which can not be measured directly using point sensors. Examples of distributed-effect sensors include piezoelectric film, holographic sensors, and modal domain optical fiber sensors. Optical fiber sensors are particularly attractive for smart structure applications because they are flexible, have low mass, and can easily be embedded directly into materials. In this paper we describe the implementation of weighted modal domain optical fiber sensors. The mathematical model of the modal domain optical fiber sensor model is described and used to derive an expression for the sensor sensitivity. The effects of parameter variations on the sensor sensitivity are demonstrated to illustrate methods of spatially varying the sensor sensitivity.

Infrared Fiber Optic Sensors

NASA Technical Reports Server (NTRS)

1997-01-01

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

Optical microscope and tapered fiber coupling apparatus for a dilution refrigerator.

PubMed

MacDonald, A J R; Popowich, G G; Hauer, B D; Kim, P H; Fredrick, A; Rojas, X; Doolin, P; Davis, J P

2015-01-01

We have developed a system for tapered fiber measurements of optomechanical resonators inside a dilution refrigerator, which is compatible with both on- and off-chip devices. Our apparatus features full three-dimensional control of the taper-resonator coupling conditions enabling critical coupling, with an overall fiber transmission efficiency of up to 70%. Notably, our design incorporates an optical microscope system consisting of a coherent bundle of 37,000 optical fibers for real-time imaging of the experiment at a resolution of ∼1 μm. We present cryogenic optical and optomechanical measurements of resonators coupled to tapered fibers at temperatures as low as 9 mK.

Recovering Signals from Optical Fiber Interferometric Sensors

DTIC Science & Technology

1991-06-01

GROUP SUB* GROUp Demodulation-, optical fiber, fi ber optic, sensors, passive -homodyne demodulation, symmetric demodul -ation, asymmetric demodulation...interferomeler without feedback control or modulation ofl th laser itself and without requiring the use of electronics withi -n the interferometer. One of...the 3x3 coupler permits Passive Homodyne Demodulation -of the phase-modulated signals provided by the interferometcr without feedback control or

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.

Fabrication of micro/nano optical fiber by mechano-electrospinning

NASA Astrophysics Data System (ADS)

Chen, Qinnan; Wu, Dezhi; Yu, Zhe; Mei, Xuecui; Fang, Ke; Sun, Daoheng

2017-10-01

We study a novel fabrication method of micro/nano optical fiber by mechano-electrospinning (MES) direct-written technology. MES process is able to precisely manipulate the position and diameter of the electro-spun micro/nano fiber by adjusting the mechanical drawing force, which through changing the speed of motion stage (substrate). By adjusting the substrate speed, the nozzle-to-substrate distance and the applied voltage, the poly(methyl methacrylate) (PMMA) micro/nano optical fibers (MNOF) with controlled diameter are obtained and the tapered MNOF are fabricated by continuously changing the substrate speed. The transmission characteristics of PMMA micro/nano fiber is experimentally demonstrated, and a PMMA micro/nano fiber based refractive index sensor is designed. Our works shows the new fabrication method of MNOF by MES has the potential in the field of light mode conversion, optical waveguide coupling, refractive index detection and new micro/nano optical fiber components.

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.

Seismic fiber optic multiplexed sensors for exploration and reservoir management

NASA Astrophysics Data System (ADS)

Houston, Mark H.

2000-12-01

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

Fiber-optical switch controlled by a single atom.

PubMed

O'Shea, Danny; Junge, Christian; Volz, Jürgen; Rauschenbeutel, Arno

2013-11-08

We demonstrate highly efficient switching of optical signals between two optical fibers controlled by a single atom. The key element of our experiment is a whispering-gallery-mode bottle microresonator, which is coupled to a single atom and interfaced by two tapered fiber couplers. This system reaches the strong coupling regime of cavity quantum electrodynamics, leading to a vacuum Rabi splitting in the excitation spectrum. We systematically investigate the switching efficiency of our system, i.e., the probability that the fiber-optical switch redirects the light into the desired output. We obtain a large redirection efficiency reaching a raw fidelity of more than 60% without postselection. Moreover, by measuring the second-order correlation functions of the output fields, we show that our switch exhibits a photon-number-dependent routing capability.

Towards mid-infrared fiber-optic devices and systems for sensing, mapping and imaging

NASA Astrophysics Data System (ADS)

Jayasuriya, D.; Wilson, B.; Furniss, D.; Tang, Z.; Barney, E.; Benson, T. M.; Seddon, A. B.

2016-03-01

Novel chalcogenide glass-based fiber opens up the mid-infrared (MIR) range for real-time monitoring and control in medical diagnostics and chemical processing. Fibers with long wavelength cut-off are of interest here. Sulfide, selenide and telluride based chalcogenide glass are candidates, but there are differences in their glass forming region, thermal stability and in the short and long wavelength cut-off positions. In general sulfide and selenide glasses have greater glass stability, but shorter long-wavelength cut-off edge, compared to telluride glasses; selenide-telluride glasses are a good compromise. Low optical loss selenide-telluride based long wavelength fibers could play a substantial role in improving medical diagnostic systems, chemical sensing, and processing, and in security and agriculture. For biological tissue, the molecular finger print lies between ~3-15 μm wavelengths in the MIR region. Using MIR spectral mapping, information about diseased tissue may be obtained with improved accuracy and in vivo using bright broadband MIR super-continuum generation (SCG) fiber sources and low optical loss fiber for routing. The Ge-As-Se-Te chalcogenide glass system is a potential candidate for both MIR SCG and passive-routing fiber, with good thermal stability, wide intrinsic transparency from ~1.5 to 20 μm and low phonon energy. This paper investigates Ge-As-Se-Te glass system pairs for developing high numerical aperture (NA) small-core, step-index optical fiber for MIR SCG and low NA passive step-index optical fiber for an in vivo fiber probe. Control of fiber geometry of small-core optical fiber and methods of producing the glass material are also included in this paper.

Optical techniques to feed and control GaAs MMIC modules for phased array antenna applications

NASA Astrophysics Data System (ADS)

Bhasin, K. B.; Anzic, G.; Kunath, R. R.; Connolly, D. J.

A complex signal distribution system is required to feed and control GaAs monolithic microwave integrated circuits (MMICs) for phased array antenna applications above 20 GHz. Each MMIC module will require one or more RF lines, one or more bias voltage lines, and digital lines to provide a minimum of 10 bits of combined phase and gain control information. In a closely spaced array, the routing of these multiple lines presents difficult topology problems as well as a high probability of signal interference. To overcome GaAs MMIC phased array signal distribution problems optical fibers interconnected to monolithically integrated optical components with GaAs MMIC array elements are proposed as a solution. System architecture considerations using optical fibers are described. The analog and digital optical links to respectively feed and control MMIC elements are analyzed. It is concluded that a fiber optic network will reduce weight and complexity, and increase reliability and performance, but higher power will be required.

Optical techniques to feed and control GaAs MMIC modules for phased array antenna applications

NASA Technical Reports Server (NTRS)

Bhasin, K. B.; Anzic, G.; Kunath, R. R.; Connolly, D. J.

1986-01-01

A complex signal distribution system is required to feed and control GaAs monolithic microwave integrated circuits (MMICs) for phased array antenna applications above 20 GHz. Each MMIC module will require one or more RF lines, one or more bias voltage lines, and digital lines to provide a minimum of 10 bits of combined phase and gain control information. In a closely spaced array, the routing of these multiple lines presents difficult topology problems as well as a high probability of signal interference. To overcome GaAs MMIC phased array signal distribution problems optical fibers interconnected to monolithically integrated optical components with GaAs MMIC array elements are proposed as a solution. System architecture considerations using optical fibers are described. The analog and digital optical links to respectively feed and control MMIC elements are analyzed. It is concluded that a fiber optic network will reduce weight and complexity, and increase reliability and performance, but higher power will be required.

ED07-0287-08

NASA Image and Video Library

2007-12-17

Although the new fiber optic sensors on the Ikhana, which are located on fibers that are the diameter of a human hair, are not visible, the sealant used to cover them can be seen in this view from above the left wing. NASA Dryden Flight Research Center is evaluating an advanced fiber optic-based sensing technology installed on the wings of NASA's Ikhana aircraft. The fiber optic system measures and displays the shape of the aircraft's wings in flight. There are other potential safety applications for the technology, such as vehicle structural health monitoring. If an aircraft structure can be monitored with sensors and a computer can manipulate flight control surfaces to compensate for stresses on the wings, structural control can be established to prevent situations that might otherwise result in a loss of control.

ED08-0109-08

NASA Image and Video Library

2008-05-01

Ikhana fiber optic wing shape sensor team: clockwise from left, Anthony "Nino" Piazza, Allen Parker, William Ko and Lance Richards. The sensors, located along a fiber the thickness of a human hair, aren't visible in the center of the Ikhana aircraft's left wing. NASA Dryden Flight Research Center is evaluating an advanced fiber optic-based sensing technology installed on the wings of NASA's Ikhana aircraft. The fiber optic system measures and displays the shape of the aircraft's wings in flight. There are other potential safety applications for the technology, such as vehicle structural health monitoring. If an aircraft structure can be monitored with sensors and a computer can manipulate flight control surfaces to compensate for stresses on the wings, structural control can be established to prevent situations that might otherwise result in a loss of control.

Production of fibers by a floating zone fiber drawing technique

NASA Technical Reports Server (NTRS)

Haggerty, J. S.

1972-01-01

A CO2 laser heated, floating zone fiber growth process was developed. The resulting Al2O3 fibers exhibited the high room temperature strengths for large diameter fibers as well as high specific creep rupture strengths observed at 1093 C and 1316 C (2000 F and 2400 F). Single crystal fibers of TiC and Y2O3 were also grown. An optical system was developed to focus four CO2 laser beams onto the surface of a feed rod permitting the formation of highly controllable molten zones. The optical system permitted energy densities and angle of incidence of the beams to be adjusted over wide ranges. This optical system was incorporated into a controlled atmosphere, fiber growth furnace. The two principal advantages of a CO2 laser heat source are that ambient atmospheres may be freely selected to optimize fiber properties and the laser has no inherent temperature limit, so extremely high melting point materials can be melted. Both advantages were demonstrated.

Theory of fiber-optic, evanescent-wave spectroscopy and sensors

NASA Astrophysics Data System (ADS)

Messica, A.; Greenstein, A.; Katzir, A.

1996-05-01

A general theory for fiber-optic, evanescent-wave spectroscopy and sensors is presented for straight, uncladded, step-index, multimode fibers. A three-dimensional model is formulated within the framework of geometric optics. The model includes various launching conditions, input and output end-face Fresnel transmission losses, multiple Fresnel reflections, bulk absorption, and evanescent-wave absorption. An evanescent-wave sensor response is analyzed as a function of externally controlled parameters such as coupling angle, f number, fiber length, and diameter. Conclusions are drawn for several experimental apparatuses.

Data transmission optical link for RF-GUN project

NASA Astrophysics Data System (ADS)

Olowski, Krzysztof; Zielinski, Jerzy; Jalmuzna, Wojciech; Pozniak, Krzysztof; Romaniuk, Ryszard

2005-09-01

Today, the fast optical data transmission is one of the fundamentals of modern distributed control systems. The fibers are widely use as multi-gigabit data stream medium. For a short range transmission, the multimode fibers are in common use. The data rate for this kind of transmission exceeds 10 Gbps for 10 Gigabit Ethernet and 10G Fibre Channel protocols. The Field Programmable Gate Arrays are one of the opportunities of managing the optical transmission. This article is concerning a synchronous optical transmission system via a multimode fiber. The transmission is controlled by the FPGA of two manufacturers: Xilinx and Altera. This paper contains the newest technology overview and market device parameters. It also describes a board for the optical transmission, technical details of the transmission and optical transmission results.

Optical sensors and multiplexing for aircraft engine control

NASA Astrophysics Data System (ADS)

Berkcan, Ertugrul

1993-02-01

Time division multiplexing of spectral modulation fiber optic sensors for aircraft engine control is presented. The paper addresses the architectural properties, the accuracy, the benefits and problems of different type of sources, the spectral stability and update times using these sources, the size, weight, and power issues, and finally the technology needs regarding FADEC mountability. The fiber optic sensors include temperature, pressure, and position spectral modulation sensors.

Recent Developments Of Optical Fiber Sensors For Automotive Use

NASA Astrophysics Data System (ADS)

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

1987-12-01

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

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.

All-optical phase shifter and switch near 1550nm using tungsten disulfide (WS2) deposited tapered fiber.

PubMed

Wu, Kan; Guo, Chaoshi; Wang, Hao; Zhang, Xiaoyan; Wang, Jun; Chen, Jianping

2017-07-24

All-optical phase shifters and switches play an important role for various all-optical applications including all-optical signal processing, sensing and communication. In this paper, we demonstrate a fiber all-optical phase shifter using few-layer 2D material tungsten disulfide (WS 2 ) deposited on a tapered fiber. WS 2 absorbs injected 980 nm pump (control light) and generates heat, which changes the refractive index of both WS 2 and tapered fiber due to thermo-optic effect and achieves a maximum phase shift of 6.1π near 1550 nm. The device has a loss of 3.7 dB. By constructing a Mach-Zehnder interferometer with WS 2 based phase shifter in one arm, an all-optical switch is also obtained with an extinction ratio of 15 dB and a rise time of 7.3 ms. This all fiber low-cost and compact optical phase shifter and switch demonstrates the potential of 2D transition metal dichalcogenides for all-optical signal processing devices.

NONLINEAR OPTICAL EFFECTS AND FIBER OPTICS: Modulation of radiation in a fiber Sagnac interferometer induced by an external field

NASA Astrophysics Data System (ADS)

Zakhidov, É. A.; Kasymdzhanov, M. A.; Mirtadzhiev, F. M.; Tartakovskiĭ, G. Kh; Khabibullaev, P. K.

1988-12-01

A study was made of the influence of the Kerr nonlinearity of a fiber waveguide on fluctuations of the output signal from a fiber-optic interferometer. The intensity fluctuations were modeled using the radiation from a pulsed high-power laser with a controlled intensity and pulse profile. Interferograms of the output radiation were obtained for different interferometer configurations. A comparison of the experiment and theory made it possible to explain the observed changes in the signal and to estimate the phase noise due to the Kerr nonlinearity in the investigated fiber waveguide.

All optical mode controllable Er-doped random fiber laser with distributed Bragg gratings.

PubMed

Zhang, W L; Ma, R; Tang, C H; Rao, Y J; Zeng, X P; Yang, Z J; Wang, Z N; Gong, Y; Wang, Y S

2015-07-01

An all-optical method to control the lasing modes of Er-doped random fiber lasers (RFLs) is proposed and demonstrated. In the RFL, an Er-doped fiber (EDF) recoded with randomly separated fiber Bragg gratings (FBG) is used as the gain medium and randomly distributed reflectors, as well as the controllable element. By combining random feedback of the FBG array and Fresnel feedback of a cleaved fiber end, multi-mode coherent random lasing is obtained with a threshold of 14 mW and power efficiency of 14.4%. Moreover, a laterally-injected control light is used to induce local gain perturbation, providing additional gain for certain random resonance modes. As a result, active mode selection of the RFL is realized by changing locations of the laser cavity that is exposed to the control light.

The family of micro sensors for remote control the pollution in liquids and gases

NASA Astrophysics Data System (ADS)

Tulaikova, Tamara; Kocharyun, Gevorg; Rogerson, Graham; Burmistrova, Ludmyla; Sychugov, Vladimir; Dorojkin, Peter

2005-10-01

There are the results for the 3 groups of fiber-optical sensors. First is the fiber-optical sensor with changed sensitive heads on the base on porous polymer with clamped activated dye. Vibration method for fiber-optical sensors provides more convenient output measurements of resonant frequency changes, in comparison with the first device. The self-focusing of the living sells into optical wave-guides in laser road in water will be considered as a new touch method for environment remote sensing.

High frequency optical communications; Proceedings of the Meeting, Cambridge, MA, Sept. 23, 24, 1986

NASA Astrophysics Data System (ADS)

Ramer, O. Glenn; Sierak, Paul

Topics discussed in this volume include systems and applications, detectors, sources, and coherent communications. Papers are presented on RF fiber optic links for avionics applications, fiber optics and optoelectronics for radar and electronic warfare applications, symmetric coplanar electrodes for high-speed Ti:LiNbO3 devices, and surface wave electrooptic modulator. Attention is given to X-band RF fiber-optic links, fiber-optic links for microwave signal transmission, GaAs monolithic receiver and laser driver for GHz transmission rates, and monolithically integrable high-speed photodetectors. Additional papers are on irregular and chaotic behavior of semiconductor lasers under modulation, high-frequency laser package for microwave optical communications, receiver modeling for coherent light wave communications, and polarization sensors and controllers for coherent optical communication systems.

The effect of force on laser fiber burnback during lithotripsy

NASA Astrophysics Data System (ADS)

Aryaei, Ashkan; Chia, Ray; Peng, Steven

2018-02-01

Optical fibers for lithotripsy are designed to deliver the maximum energy precisely to the treatment site without a decrease in performance and without increasing the risks to patients and users. One of the obstacles to constant energy delivery is burnback of the optical fiber tip. So far, researchers identified mechanical, thermal, and optical factors as mechanisms in burnback phenomena. Among mechanical factors, the force applied by urologists against a stone is expected to play a dominant role in burnback. In this study, we introduce a novel technique to measure accurately the stone depth and volume ablation under varying force. Our results show varying burnback lengths on the optical fibers and varying stone depth and volume ablation depending on the optical fiber core size. For instance, the slope of the burnback as a function of the applied force for 273 μm fibers was more than two times higher than for the 550 μm fibers. The slope of the total volume of stone ablated as function of force for 550 μm fibers was almost twice as much as for the 273 μm fibers. The data suggest urologists can maximize the stone ablation rate and minimize fiber tip burnback by controlling the applied force on the optical fiber during a lithotripsy procedure.

Active control for vibration suppression in a flexible beam using a modal domain optical fiber sensor

NASA Technical Reports Server (NTRS)

Cox, D. E.; Lindner, D. K.

1991-01-01

An account is given of the use of a modal-domain (MD) fiber-optic sensor as an active control system component for vibration suppression, whose output is proportional to the integral of the axial strain along the optical fiber. When an MD sensor is attached to, or embedded in, a flexible structure, it senses the strain in the structure along its gage length. On the basis of the present integration of the sensor model into a flexible-structure model, it becomes possible to design a control system with a dynamic compensator which adds damping to the low-order modes of the flexible structure. This modeling procedure has been experimentally validated.

Lightweight fiber optic microphones and accelerometers

NASA Astrophysics Data System (ADS)

Bucaro, J. A.; Lagakos, N.

2001-06-01

We have designed, fabricated, and tested two lightweight fiber optic sensors for the dynamic measurement of acoustic pressure and acceleration. These sensors, one a microphone and the other an accelerometer, are required for active blanket sound control technology under development in our laboratory. The sensors were designed to perform to certain specifications dictated by our active sound control application and to do so without exhibiting sensitivity to the high electrical voltages expected to be present. Furthermore, the devices had to be small (volumes less than 1.5 cm3) and light (less than 2 g). To achieve these design criteria, we modified and extended fiber optic reflection microphone and fiber microbend displacement device designs reported in the literature. After fabrication, the performances of each sensor type were determined from measurements made in a dynamic pressure calibrator and on a shaker table. The fiber optic microbend accelerometer, which weighs less than 1.8 g, was found to meet all performance goals including 1% linearity, 90 dB dynamic range, and a minimum detectable acceleration of 0.2 mg/√Hz . The fiber optic microphone, which weighs less than 1.3 g, also met all goals including 1% linearity, 85 dB dynamic range, and a minimum detectable acoustic pressure level of 0.016 Pa/√Hz . In addition to our specific use in active sound control, these sensors appear to have application in a variety of other areas.

Laser backlight unit based on a leaky optical fiber

NASA Astrophysics Data System (ADS)

Okuda, Yuuto; Onoda, Kousuke; Fujieda, Ichiro

2012-07-01

A backlight unit is constructed by laying out an optical fiber on a two-dimensional plane and letting the light leak out in a controlled manner. In experiment, we formed multiple grooves on the surface of a plastic optical fiber by pressing a heated knife edge. The depth of the groove determined the percentage of the optical power leaking out. The optical fiber with multiple grooves was embedded in an acrylic plate with a spiral trench, and a diffuser sheet was placed over it. When we injected laser light into the end of the optical fiber, this configuration successfully worked as an area illuminator. However, the coherent nature of the laser light caused severe speckle noise. We evaluated the speckle contrast under darkness, and it varied from 80% to 23%, depending on the lens aperture used to capture the images of the illuminator. We glued an ultrasound generator to the optical fiber to introduce phase modulation for the light propagating inside the optical fiber. In this way, the speckle contrast was reduced by a factor of seven to four. Under room lighting, the speckle noise was made barely noticeable by turning on the ultrasound generator.

Dynamic illumination of spatially restricted or large brain volumes via a single tapered optical fiber

PubMed Central

Pisanello, Marco; Oldenburg, Ian A.; Sileo, Leonardo; Markowitz, Jeffrey E.; Peterson, Ralph E.; Della Patria, Andrea; Haynes, Trevor M.; Emara, Mohamed S.; Spagnolo, Barbara; Datta, Sandeep Robert; De Vittorio, Massimo; Sabatini, Bernardo L.

2017-01-01

Optogenetics promises spatiotemporal precise control of neural processes using light. However, the spatial extent of illumination within the brain is difficult to control and cannot be adjusted using standard fiber optics. We demonstrate that optical fibers with tapered tips can be used to illuminate either spatially restricted or large brain volumes. Remotely adjusting the light input angle to the fiber varies the light-emitting portion of the taper over several millimeters without movement of the implant. We use this mode to activate dorsal versus ventral striatum of individual mice and reveal different effects of each manipulation on motor behavior. Conversely, injecting light over the full numerical aperture of the fiber results in light emission from the entire taper surface, achieving broader and more efficient optogenetic activation of neurons when compared to the standard flat-faced fiber stimulation. Thus, tapered fibers permit focal or broad illumination that can be precisely and dynamically matched to experimental needs. PMID:28628101

Dynamic illumination of spatially restricted or large brain volumes via a single tapered optical fiber.

PubMed

Pisanello, Ferruccio; Mandelbaum, Gil; Pisanello, Marco; Oldenburg, Ian A; Sileo, Leonardo; Markowitz, Jeffrey E; Peterson, Ralph E; Della Patria, Andrea; Haynes, Trevor M; Emara, Mohamed S; Spagnolo, Barbara; Datta, Sandeep Robert; De Vittorio, Massimo; Sabatini, Bernardo L

2017-08-01

Optogenetics promises precise spatiotemporal control of neural processes using light. However, the spatial extent of illumination within the brain is difficult to control and cannot be adjusted using standard fiber optics. We demonstrate that optical fibers with tapered tips can be used to illuminate either spatially restricted or large brain volumes. Remotely adjusting the light input angle to the fiber varies the light-emitting portion of the taper over several millimeters without movement of the implant. We use this mode to activate dorsal versus ventral striatum of individual mice and reveal different effects of each manipulation on motor behavior. Conversely, injecting light over the full numerical aperture of the fiber results in light emission from the entire taper surface, achieving broader and more efficient optogenetic activation of neurons, compared to standard flat-faced fiber stimulation. Thus, tapered fibers permit focal or broad illumination that can be precisely and dynamically matched to experimental needs.

Integrated optics technology study

NASA Technical Reports Server (NTRS)

Chen, B.; Findakly, T.; Innarella, R.

1982-01-01

The status and near term potential of materials and processes available for the fabrication of single mode integrated electro-optical components are discussed. Issues discussed are host material and orientation, waveguide formation, optical loss mechanisms, wavelength selection, polarization effects and control, laser to integrated optics coupling fiber optic waveguides to integrated optics coupling, sources, and detectors. Recommendations of the best materials, technology, and processes for fabrication of integrated optical components for communications and fiber gyro applications are given.

Fiber-optic photoelastic pressure sensor with fiber-loss compensation

NASA Technical Reports Server (NTRS)

Beheim, G.; Anthan, D. J.

1987-01-01

A new fiber-optic pressure sensor is described that has high immunity to the effects of fiber-loss variations. This device uses the photoelastic effect to modulate the proportion of the light from each of two input fibers that is coupled into each of two output fibers. This four-fiber link permits two detectors to be used to measure the sensor's responses to the light from each of two independently controlled sources. These four detector outputs are processed to yield a loss-compensated signal that is a stable and sensitive pressure indicator.

Multiplexing electro-optic architectures for advanced aircraft integrated flight control systems

NASA Technical Reports Server (NTRS)

Seal, D. W.

1989-01-01

This report describes the results of a 10 month program sponsored by NASA. The objective of this program was to evaluate various optical sensor modulation technologies and to design an optimal Electro-Optic Architecture (EOA) for servicing remote clusters of sensors and actuators in advanced aircraft flight control systems. The EOA's supply optical power to remote sensors and actuators, process the modulated optical signals returned from the sensors, and produce conditioned electrical signals acceptable for use by a digital flight control computer or Vehicle Management System (VMS) computer. This study was part of a multi-year initiative under the Fiber Optic Control System Integration (FOCSI) program to design, develop, and test a totally integrated fiber optic flight/propulsion control system for application to advanced aircraft. Unlike earlier FOCSI studies, this program concentrated on the design of the EOA interface rather than the optical transducer technology itself.

Optical trapping and control of nanoparticles inside evacuated hollow core photonic crystal fibers

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

Grass, David, E-mail: david.grass@univie.ac.at; Fesel, Julian; Hofer, Sebastian G.

2016-05-30

We demonstrate an optical conveyor belt for levitated nanoparticles over several centimeters inside both air-filled and evacuated hollow-core photonic crystal fibers (HCPCF). Detection of the transmitted light field allows three-dimensional read-out of the particle center-of-mass motion. An additional laser enables axial radiation pressure based feedback cooling over the full fiber length. We show that the particle dynamics is a sensitive local probe for characterizing the optical intensity profile inside the fiber as well as the pressure distribution along the fiber axis. In contrast to some theoretical predictions, we find a linear pressure dependence inside the HCPCF, extending over three ordersmore » of magnitude from 0.2 mbar to 100 mbar. A targeted application is the controlled delivery of nanoparticles from ambient pressure into medium vacuum.« less

Fiber-optic temperature probe system for inner body

NASA Astrophysics Data System (ADS)

Liu, Bo; Deng, Xing-Zhong; Cao, Wei; Cheng, Xianping; Xie, Tuqiang; Zhong, Zugen

1991-08-01

The authors have designed a fiber-optic temperature probe system that can quickly insert its probe into bodies to measure temperature. Its thermometer unit has the function of program- controlled zeroing. The single-chip microcomputer is used to control the whole system and process data. The sample system has been tested in a coal furnace.

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

NASA Technical Reports Server (NTRS)

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

1991-01-01

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

Active phase compensation system for fiber optic holography

NASA Technical Reports Server (NTRS)

Mercer, Carolyn R.; Beheim, Glenn

1988-01-01

Fiber optic delivery systems promise to extend the application of holography to severe environments by simplifying test configurations and permitting the laser to be remotely placed in a more benign location. However, the introduction of optical fiber leads to phase stability problems. Environmental effects cause the pathlengths of the fibers to change randomly, preventing the formation of stationary interference patterns which are required for holography. An active phase control system has been designed and used with an all-fiber optical system to stabilize the phase difference between light emitted from two fibers, and to step the phase difference by 90 deg without applying any constraints on the placement of the fibers. The accuracy of the phase steps is shown to be better than 0.02 deg., and a stable phase difference can be maintained for 30 min. This system can be applied to both conventional and electro-optic holography, as well as to any system where the maintenance of an accurate phase difference between two coherent beams is required.

Active phase compensation system for fiber optic holography

NASA Technical Reports Server (NTRS)

Mercer, Carolyn R.; Beheim, Glenn

1989-01-01

Fiber optic delivery systems promise to extend the application of holography to severe environments by simplifying test configurations and permitting the laser to be remotely placed in a more benign location. However, the introduction of optical fiber leads to phase stability problems. Environmental effects cause the pathlengths of the fibers to change randomly, preventing the formation of stationary interference patterns which are required for holography. An active phase control system has been designed and used with an all-fiber optical system to stabilize the phase difference between light emitted from two fibers, and to step the phase difference by 90 deg without applying any constraints on the placement of the fibers. The accuracy of the phase steps is shown to be better than 0.02 deg., and a stable phase difference can be maintained for 30 min. This system can be applied to both conventional and electro-optic holography, as well as to any system where the maintenance of an accurate phase difference between two coherent beams is required.

Analysis and experimental demonstration of conformal adaptive phase-locked fiber array for laser communications and beam projection applications

NASA Astrophysics Data System (ADS)

Liu, Ling

The primary goal of this research is the analysis, development, and experimental demonstration of an adaptive phase-locked fiber array system for free-space optical communications and laser beam projection applications. To our knowledge, the developed adaptive phase-locked system composed of three fiber collimators (subapertures) with tip-tilt wavefront phase control at each subaperture represents the first reported fiber array system that implements both phase-locking control and adaptive wavefront tip-tilt control capabilities. This research has also resulted in the following innovations: (a) The first experimental demonstration of a phase-locked fiber array with tip-tilt wave-front aberration compensation at each fiber collimator; (b) Development and demonstration of the fastest currently reported stochastic parallel gradient descent (SPGD) system capable of operation at 180,000 iterations per second; (c) The first experimental demonstration of a laser communication link based on a phase-locked fiber array; (d) The first successful experimental demonstration of turbulence and jitter-induced phase distortion compensation in a phase-locked fiber array optical system; (e) The first demonstration of laser beam projection onto an extended target with a randomly rough surface using a conformal adaptive fiber array system. Fiber array optical systems, the subject of this study, can overcome some of the draw-backs of conventional monolithic large-aperture transmitter/receiver optical systems that are usually heavy, bulky, and expensive. The primary experimental challenges in the development of the adaptive phased-locked fiber-array included precise (<5 microrad) alignment of the fiber collimators and development of fast (100kHz-class) phase-locking and wavefront tip-tilt control systems. The precise alignment of the fiber collimator array is achieved through a specially developed initial coarse alignment tool based on high precision piezoelectric picomotors and a dynamic fine alignment mechanism implemented with specially designed and manufactured piezoelectric fiber positioners. Phase-locking of the fiber collimators is performed by controlling the phases of the output beams (beamlets) using integrated polarization-maintaining (PM) fiber-coupled LiNbO3 phase shifters. The developed phase-locking controllers are based on either the SPGD algorithm or the multi-dithering technique. Subaperture wavefront phase tip-tilt control is realized using piezoelectric fiber positioners that are controlled using a computer-based SPGD controller. Both coherent (phase-locked) and incoherent beam combining in the fiber array system are analyzed theoretically and experimentally. Two special fiber-based beam-combining testbeds have been built to demonstrate the technical feasibility of phase-locking compensation prior to free-space operation. In addition, the reciprocity of counter-propagating beams in a phase-locked fiber array system has been investigated. Coherent beam combining in a phase-locking system with wavefront phase tip-tilt compensation at each subaperture is successfully demonstrated when laboratory-simulated turbulence and wavefront jitters are present in the propagation path of the beamlets. In addition, coherent beam combining with a non-cooperative extended target in the control loop is successfully demonstrated.

Submicron diameter single crystal sapphire optical fiber

DOE PAGES

Hill, Cary; Homa, Daniel; Liu, Bo; ...

2014-10-02

In this work, a submicron-diameter single crystal sapphire optical fiber was demonstrated via wet acid etching at elevated temperatures. Etch rates on the order 2.3 µm/hr were achievable with a 3:1 molar ratio sulfuric-phosphoric acid solution maintained at a temperature of 343°C. A sapphire fiber with an approximate diameter of 800 nm was successfully fabricated from a commercially available fiber with an original diameter of 50 µm. The simple and controllable etching technique provides a feasible approach to the fabrication of unique waveguide structures via traditional silica masking techniques. The ability to tailor the geometry of sapphire optical fibers ismore » the first step in achieving optical and sensing performance on par with its fused silica counterpart.« less

Fiber optics welder having movable aligning mirror

DOEpatents

Higgins, Robert W.; Robichaud, Roger E.

1981-01-01

A system for welding fiber optic waveguides together. The ends of the two fibers to be joined together are accurately, collinearly aligned in a vertical orientation and subjected to a controlled, diffuse arc to effect welding and thermal conditioning. A front-surfaced mirror mounted at a 45.degree. angle to the optical axis of a stereomicroscope mounted for viewing the junction of the ends provides two orthogonal views of the interface during the alignment operation.

Fiber optics welder

DOEpatents

Higgins, R.W.; Robichaud, R.E.

A system is described for welding fiber optic waveguides together. The ends of the two fibers to be joined together are accurately, collinearly aligned in a vertical orientation and subjected to a controlled, diffuse arc to effect welding and thermal conditioning. A front-surfaced mirror mounted at a 45/sup 0/ angle to the optical axis of a stereomicroscope mounted for viewing the junction of the ends provides two orthogonal views of the interface during the alignment operation.

Stress corrosion in silica optical fibers: Review of fatigue testing procedures

NASA Astrophysics Data System (ADS)

Severin, Irina; Borda, Claudia; Dumitrache-Rujinski, Alexandru; Caramihai, Mihai; Abdi, Rochdi El

2018-02-01

The expected lifetime of optical fibers used either in telecommunication technologies or smart applications are closely related to the chemical reaction on the silica network. Due to the manufacturing processes or the handling procedures, the flaws spread on the fiber surface are inherently present. The aging mechanism is assumed to enlarge or to extend these flaws. Based on systematic experiments one may notice that water may induce a certain curing effect. Silica optical fibers have been aged in water; series of samples have been subjected to overlapped stretching or bending. Other series have been subjected to overlapped aging effect of microwaves and hot water. Finally, samples were submitted to dynamic tensile testing. The Weibull's diagram analysis shows mono or bimodal dispersions of flaws on the fiber surface, but the polymer coating appears vital for fiber lifetime. While humidity usually affects the fiber strength, the series of testing has revealed that in controlled conditions of chemical environment and controlled applied stress, fiber strength may be increased. A similar effect may be obtained by external factors such as microwaves or previous elongation, too.

Recent developments in optical fibers and how defense, security, and sensing can benefit

NASA Astrophysics Data System (ADS)

Régnier, E.; Burov, E.; Pastouret, A.; Boivin, D.; Kuyt, G.; Gooijer, F.; Bergonzo, A.; Berkers, A.; Signoret, P.; Troussellier, L.; Storaasli, O.; Nouchi, P.

2009-05-01

For many years, fiber manufacturers have devoted research efforts to develop fibers with improved radiation resistance, keeping the same advantages and basic properties as standard fibers. Today, both single-mode (SMF) and multimode (MMF) RadHard (for Radiation-Hardened) fibers are available; some of them are MIL-49291 certified and are already used, for example in military applications and at the Large Hadron Collider (LHC) in CERN or in certain nuclear power plants. These RadHard fibers can be easily connected to standard optical networks for classical data transfer or they can also be used for command control. Using some specific properties (Raman or Brillouin scattering, Bragg gratings...), such fibers can also be used as distributed sensing (temperature or strain sensors, etc) in radiation environments. At least, optical fibers can also be used for signal amplification, either in telecom networks, or in fiber lasers. This last category of fibers is called active fibers, in opposition to passive fibers used for simple signal transmission. Draka has also recently worked to improve the radiation-resistance of these active fibers, so that Draka can now offer RadHard fibers for full optical systems.

Adaptive fiber optics collimator based on flexible hinges.

PubMed

Zhi, Dong; Ma, Yanxing; Ma, Pengfei; Si, Lei; Wang, Xiaolin; Zhou, Pu

2014-08-20

In this manuscript, we present a new design for an adaptive fiber optics collimator (AFOC) based on flexible hinges by using piezoelectric stacks actuators for X-Y displacement. Different from traditional AFOC, the new structure is based on flexible hinges to drive the fiber end cap instead of naked fiber. We fabricated a real AFOC based on flexible hinges, and the end cap's deviation and resonance frequency of the device were measured. Experimental results show that this new AFOC can provide fast control of tip-tilt deviation of the laser beam emitting from the end cap. As a result, the fiber end cap can support much higher power than naked fiber, which makes the new structure ideal for tip-tilt controlling in a high-power fiber laser system.

Fiber optic hydrogen sensor

DOEpatents

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

1991-01-01

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

Fiber optic hydrogen sensor

DOEpatents

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

1992-10-06

An apparatus and method are described for detecting a chemical substance by exposing an optic fiber having a core and a cladding to the chemical substance so that the chemical substance can be adsorbed onto the surface of the cladding. The optic fiber is coiled inside a container having a pair of valves for controlling the entrance and exit of the substance. Light from a light source is received by one end of the optic fiber, preferably external to the container, and carried by the core of the fiber. Adsorbed substance changes the transmissivity of the fiber as measured by a spectrophotometer at the other end, also preferably external to the container. Hydrogen is detected by the absorption of infrared light carried by an optic fiber with a silica cladding. Since the adsorption is reversible, a sensor according to the present invention can be used repeatedly. Multiple positions in a process system can be monitored using a single container that can be connected to each location to be monitored so that a sample can be obtained for measurement, or, alternatively, containers can be placed near each position and the optic fibers carrying the partially-absorbed light can be multiplexed for rapid sequential reading by a single spectrophotometer. 4 figs.

Fiber optic hydrogen sensor

DOEpatents

Buchanan, Bruce R.; Prather, William S.

1992-01-01

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

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 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.

Guidance and control of MIR TDL radiation via flexible hollow metallic rectangular pipes and fibers for possible LHS and other optical system compaction and integration

NASA Technical Reports Server (NTRS)

Yu, C.

1983-01-01

Flexible hollow metallic rectangular pipes and infrared fibers are proposed as alternate media for collection, guidance and manipulation of mid-infrared tunable diode laser (TDL) radiation. Certain features of such media are found to be useful for control of TDL far field patterns, polarization and possibly intensity fluctuations. Such improvement in dimension compatibility may eventually lead to laser heterodyne spectroscopy (LHS) and optical communication system compaction and integration. Infrared optical fiber and the compound parabolic coupling of light into a hollow pipe waveguide are discussed as well as the design of the waveguide.

Optical fiber sensors and signal processing for intelligent structure monitoring

NASA Technical Reports Server (NTRS)

Thomas, Daniel; Cox, Dave; Lindner, D. K.; Claus, R. O.

1989-01-01

Few mode optical fibers have been shown to produce predictable interference patterns when placed under strain. The use is described of a modal domain sensor in a vibration control experiment. An optical fiber is bonded along the length of a flexible beam. Output from the modal domain sensor is used to suppress vibrations induced in the beam. A distributed effect model for the modal domain sensor is developed. This model is combined with the beam and actuator dynamics to produce a system suitable for control design. Computer simulations predict open and closed loop dynamic responses. An experimental apparatus is described and experimental results are presented.

Comparison on different repetition rate locking methods in Er-doped fiber laser

NASA Astrophysics Data System (ADS)

Yang, Kangwen; Zhao, Peng; Luo, Jiang; Huang, Kun; Hao, Qiang; Zeng, Heping

2018-05-01

We demonstrate a systematic comparative research on the all-optical, mechanical and opto-mechanical repetition rate control methods in an Er-doped fiber laser. A piece of Yb-doped fiber, a piezoelectric transducer and an electronic polarization controller are simultaneously added in the laser cavity as different cavity length modulators. By measuring the cavity length tuning ranges, the output power fluctuations, the temporal and frequency repetition rate stability, we show that all-optical method introduces the minimal disturbances under current experimental condition.

ED08-0016-20

NASA Image and Video Library

2008-01-17

NASA engineer Larry Hudson and Ikhana ground crew member James Smith work on a ground validation test with new fiber optic sensors that led to validation flights on the Ikhana aircraft. NASA Dryden Flight Research Center is evaluating an advanced fiber optic-based sensing technology installed on the wings of NASA's Ikhana aircraft. The fiber optic system measures and displays the shape of the aircraft's wings in flight. There are other potential safety applications for the technology, such as vehicle structural health monitoring. If an aircraft structure can be monitored with sensors and a computer can manipulate flight control surfaces to compensate for stresses on the wings, structural control can be established to prevent situations that might otherwise result in a loss of control.

Application and the key technology on high power fiber-optic laser in laser weapon

NASA Astrophysics Data System (ADS)

Qu, Zhou; Li, Qiushi; Meng, Haihong; Sui, Xin; Zhang, Hongtao; Zhai, Xuhua

2014-12-01

The soft-killing laser weapon plays an important role in photoelectric defense technology. It can be used for photoelectric detection, search, blinding of photoelectric sensor and other devices on fire control and guidance devices, therefore it draws more and more attentions by many scholars. High power fiber-optic laser has many virtues such as small volume, simple structure, nimble handling, high efficiency, qualified light beam, easy thermal management, leading to blinding. Consequently, it may be used as the key device of soft-killing laser weapon. The present study introduced the development of high power fiber-optic laser and its main features. Meanwhile the key technology of large mode area (LMA) optical fiber design, the beam combination technology, double-clad fiber technology and pumping optical coupling technology was stated. The present study is aimed to design high doping LMA fiber, ensure single mode output by increasing core diameter and decrease NA. By means of reducing the spontaneous emission particle absorbed by fiber core and Increasing the power density in the optical fiber, the threshold power of nonlinear effect can increase, and the power of single fiber will be improved. Meantime, high power will be obtained by the beam combination technology. Application prospect of high power fiber laser in photoelectric defense technology was also set forth. Lastly, the present study explored the advantages of high power fiber laser in photoelectric defense technology.

Water-Cooled Optical Thermometer

NASA Technical Reports Server (NTRS)

Menna, A. A.

1987-01-01

Water-cooled optical probe measures temperature of nearby radiating object. Intended primarily for use in silicon-growing furnace for measuring and controlling temperatures of silicon ribbon, meniscus, cartridge surfaces, heaters, or other parts. Cooling water and flushing gas cool fiber-optic probe and keep it clean. Fiber passes thermal radiation from observed surface to measuring instrument.

Lightning vulnerability of fiber-optic cables.

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

Martinez, Leonard E.; Caldwell, Michele

2008-06-01

One reason to use optical fibers to transmit data is for isolation from unintended electrical energy. Using fiber optics in an application where the fiber cable/system penetrates the aperture of a grounded enclosure serves two purposes: first, it allows for control signals to be transmitted where they are required, and second, the insulating properties of the fiber system help to electrically isolate the fiber terminations on the inside of the grounded enclosure. A fundamental question is whether fiber optic cables can allow electrical energy to pass through a grounded enclosure, with a lightning strike representing an extreme but very importantmore » case. A DC test bed capable of producing voltages up to 200 kV was used to characterize electrical properties of a variety of fiber optic cable samples. Leakage current in the samples were measured with a micro-Ammeter. In addition to the leakage current measurements, samples were also tested to DC voltage breakdown. After the fiber optic cables samples were tested with DC methods, they were tested under representative lightning conditions at the Sandia Lightning Simulator (SLS). Simulated lightning currents of 30 kA and 200 kA were selected for this test series. This paper documents measurement methods and test results for DC high voltage and simulated lightning tests performed at the Sandia Lightning Simulator on fiber optic cables. The tests performed at the SLS evaluated whether electrical energy can be conducted inside or along the surface of a fiber optic cable into a grounded enclosure under representative lightning conditions.« less

Optical Antenna Arrays on a Fiber Facet for In Situ Surface Enhanced Raman Scattering Detection

PubMed Central

Smythe, Elizabeth J.; Dickey, Michael D.; Bao, Jiming; Whitesides, George M.

2009-01-01

This paper reports a bidirectional fiber optic probe for the detection of surface enhanced Raman scattering (SERS). One facet of the probe features an array of gold optical antennas designed to enhance Raman signal, while the other facet of the fiber is used for the input and collection of light. Simultaneous detection of benzenethiol and 2-[(E)-2-pyridin-4-ylethenyl]pyridine is demonstrated through a 35 cm long fiber. The array of nanoscale optical antennas was first defined by electron-beam lithography on a silicon wafer. The array was subsequently stripped from the wafer and then transferred to the facet of a fiber. Lithographic definition of the antennas provides a method for producing two-dimensional arrays with well-defined geometry, which allows (i) the optical response of the probe to be tuned and (ii) the density of ‘hot spots’ generating the enhanced Raman signal to be controlled. It is difficult to determine the Raman signal enhancement factor (EF) of most fiber optic Raman sensors featuring ‘hot spots’ because the geometry of the Raman enhancing nanostructures is poorly defined. The ability to control the size and spacing of the antennas enables the EF of the transferred array to be estimated. EF values estimated after focusing a laser directly onto the transferred array ranged from 2.6 × 105 to 5.1 × 105. PMID:19236032

Controlled generation of different orbital angular momentum states in a hybrid optical fiber

NASA Astrophysics Data System (ADS)

Heng, Xiaobo; Gan, Jiulin; Zhang, Zhishen; Qian, Qi; Xu, Shanhui; Yang, Zhongmin

2017-11-01

A new kind of hybrid optical fiber for different orbital angular momentum (OAM) states generation is proposed and investigated by simulation. The hybrid fiber is composed of three main regions: the core, the cladding and the bow-tie-shaped stress-applying zones (SAZs). The SAZs are symmetrically distributed on both sides of the core and filled with piezoelectric material PZT-5H which would generate radial mechanical movement when subjected to an electric field. The strain applied by the SAZs introduces anisotropic variation of the material permittivity which affect the propagation of the guided modes along the fiber core. The OAM modes of | l | = 1 , 2 , 3 can be generated by setting the appropriate electric potential applied in the SAZs. This fiber-based structure and electric control design enable the generation and adjustment of OAM states with the merits of accuracy, compactness and practicality, which would have potential application in OAM optical fiber communication systems and other systems utilizing OAM light.

A hybrid optic-fiber sensor network with the function of self-diagnosis and self-healing

NASA Astrophysics Data System (ADS)

Xu, Shibo; Liu, Tiegen; Ge, Chunfeng; Chen, Cheng; Zhang, Hongxia

2014-11-01

We develop a hybrid wavelength division multiplexing optical fiber network with distributed fiber-optic sensors and quasi-distributed FBG sensor arrays which detect vibrations, temperatures and strains at the same time. The network has the ability to locate the failure sites automatically designated as self-diagnosis and make protective switching to reestablish sensing service designated as self-healing by cooperative work of software and hardware. The processes above are accomplished by master-slave processors with the help of optical and wireless telemetry signals. All the sensing and optical telemetry signals transmit in the same fiber either working fiber or backup fiber. We take wavelength 1450nm as downstream signal and wavelength 1350nm as upstream signal to control the network in normal circumstances, both signals are sent by a light emitting node of the corresponding processor. There is also a continuous laser wavelength 1310nm sent by each node and received by next node on both working and backup fibers to monitor their healthy states, but it does not carry any message like telemetry signals do. When fibers of two sensor units are completely damaged, the master processor will lose the communication with the node between the damaged ones.However we install RF module in each node to solve the possible problem. Finally, the whole network state is transmitted to host computer by master processor. Operator could know and control the network by human-machine interface if needed.

Optical stabilization for time transfer infrastructure

NASA Astrophysics Data System (ADS)

Vojtech, Josef; Altmann, Michal; Skoda, Pavel; Horvath, Tomas; Slapak, Martin; Smotlacha, Vladimir; Havlis, Ondrej; Munster, Petr; Radil, Jan; Kundrat, Jan; Altmannova, Lada; Velc, Radek; Hula, Miloslav; Vohnout, Rudolf

2017-08-01

In this paper, we propose and present verification of all-optical methods for stabilization of the end-to-end delay of an optical fiber link. These methods are verified for deployment within infrastructure for accurate time and stable frequency distribution, based on sharing of fibers with research and educational network carrying live data traffic. Methods range from path length control, through temperature conditioning method to transmit wavelength control. Attention is given to achieve continuous control for relatively broad range of delays. We summarize design rules for delay stabilization based on the character and the total delay jitter.

Integrated optics technology study

NASA Technical Reports Server (NTRS)

Chen, B.

1982-01-01

The materials and processes available for the fabrication of single mode integrated electrooptical components are described. Issues included in the study are: (1) host material and orientation, (2) waveguide formation, (3) optical loss mechanisms, (4) wavelength selection, (5) polarization effects and control, (6) laser to integrated optics coupling,(7) fiber optic waveguides to integrated optics coupling, (8) souces, (9) detectors. The best materials, technology and processes for fabrication of integrated optical components for communications and fiber gyro applications are recommended.

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.

Ultra-low-loss optical fiber nanotapers.

PubMed

Brambilla, Gilberto; Finazzi, Vittoria; Richardson, David

2004-05-17

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

Fiber-optic sensor demonstrator (FSD) for the monitoring of spacecraft subsystems on ESA's PROBA-2

NASA Astrophysics Data System (ADS)

Kruzelecky, Roman V.; Zou, Jing; Mohammed, Najeeb; Haddad, Emile; Jamroz, Wes; Ricci, Francesco; Lamorie, Joshua; Edwards, Eric; McKenzie, Iain; Vuilleumier, Pierrik

2017-11-01

MPB Communications (MPBC) is developing solutions to the monitoring requirements of spacecraft based on its fiber-laser and Fiber Bragg Grating expertise. This is cumulating in the Fiber Sensor Demonstrator for ESA's Proba-2 that is scheduled for launch in 2007. The advantages of the MPBC approach include a central interrogation system that can be used to control a variety of different fiber-optic sensors including temperature, pressure, actuator status, and propellant leakage. This paper reviews the design and ground qualification of the FSD system in preparation for integration with Proba-2. The FSD will provide monitoring for various Proba-2 subsystems, including a hybrid propulsion system. Some of the challenges associated with using fiber-optics in space are discussed.

Dopants concentration effects on the wavelength shift of long-period fiber gratings used as liquid level detectors

NASA Astrophysics Data System (ADS)

Mao, Barerem-Melgueba; Zhou, Bin

2011-12-01

Two liquid level sensors based on different long-period fiber gratings are proposed and compared. The long-period gratings have the same characteristics (length, grating period) but are fabricated in different optical fibers (photosensitive B-Ge codoped optical fibers with different dopants concentrations). The principle of this type of sensor is based on the refractive index sensitivity of long-period fiber gratings. By monitoring the resonant wavelength shifts of a given attenuation band, one can measure the immersed lengths of long-period fiber gratings and then the liquid level. The levels of two different solutions are measured. The maximum shift (7.69 nm) of the investigated resonance wavelength was observed in LPG1 (fabricated in Fibercore PS1250/1500). By controlling the fiber dopants concentrations one can improve the readouts of a fiber-optic liquid level sensor based on long-period fiber gratings.

Sensitivity optimization of ZnO clad-modified optical fiber humidity sensor by means of tuning the optical fiber waist diameter

NASA Astrophysics Data System (ADS)

Azad, Saeed; Sadeghi, Ebrahim; Parvizi, Roghaieh; Mazaheri, Azardokht; Yousefi, M.

2017-05-01

In this work, the multimode optical fiber size effects on the performances of the clad-modified fiber with ZnO nanorods relative humidity (RH) sensor were experimentally investigated. Simple and controlled chemical etching method through on line monitoring was used to prepare different fiber waist diameter with long length of 15 mm. More precisely, the competition behavior of sensor performances with varying fiber waist diameter was studied to find appropriate size of maximizing evanescent fields. The obtained results revealed that evanescent wave absorption coefficient (γ) enhanced more than 10 times compare to bare fiber at the proposed optimum fiber diameter of 28 μm. Also, high linearity and fast recovery time about 7 s was obtained at the proposed fiber waist diameter. Applicable features of the proposed sensor allow this device to be used for humidity sensing applications, especially to be applied in remote sensing technologies.

Photonic-powered cable assembly

DOEpatents

Sanderson, Stephen N.; Appel, Titus James; Wrye, IV, Walter C.

2013-01-22

A photonic-cable assembly includes a power source cable connector ("PSCC") coupled to a power receive cable connector ("PRCC") via a fiber cable. The PSCC electrically connects to a first electronic device and houses a photonic power source and an optical data transmitter. The fiber cable includes an optical transmit data path coupled to the optical data transmitter, an optical power path coupled to the photonic power source, and an optical feedback path coupled to provide feedback control to the photonic power source. The PRCC electrically connects to a second electronic device and houses an optical data receiver coupled to the optical transmit data path, a feedback controller coupled to the optical feedback path to control the photonic power source, and a photonic power converter coupled to the optical power path to convert photonic energy received over the optical power path to electrical energy to power components of the PRCC.

Photonic-powered cable assembly

DOEpatents

Sanderson, Stephen N; Appel, Titus James; Wrye, IV, Walter C

2014-06-24

A photonic-cable assembly includes a power source cable connector ("PSCC") coupled to a power receive cable connector ("PRCC") via a fiber cable. The PSCC electrically connects to a first electronic device and houses a photonic power source and an optical data transmitter. The fiber cable includes an optical transmit data path coupled to the optical data transmitter, an optical power path coupled to the photonic power source, and an optical feedback path coupled to provide feedback control to the photonic power source. The PRCC electrically connects to a second electronic device and houses an optical data receiver coupled to the optical transmit data path, a feedback controller coupled to the optical feedback path to control the photonic power source, and a photonic power converter coupled to the optical power path to convert photonic energy received over the optical power path to electrical energy to power components of the PRCC.

Modeling, Simulation, and Analysis of a Decoy State Enabled Quantum Key Distribution System

DTIC Science & Technology

2015-03-26

through the fiber , we assume Alice and Bob have correct basis alignment and timing control for reference frame correction and precise photon detection...optical components ( laser , polarization modulator, electronic variable optical attenuator, fixed optical attenuator, fiber channel, beamsplitter...generated by the laser in the CPG propagate through multiple optical components, each with a unique propagation delay before reaching the OPM. Timing

Introduction to fiber optics: Sensors for biomedical applications.

PubMed

Shah, R Y; Agrawal, Y K

2011-01-01

The paper focuses on the introduction of fiber optics, a fusion of science and engineering and describes the materials generally used for its construction along with the procedure used to design the fibers. It gives an idea of the materials used for the construction along with the pros and cons associated with them and various factors governing the emission of ultraviolet, infrared or visible radiations. The central core revolves around the applications of optical fibers in the medical and biomedical field and extending the use of the same in pharmaceutical industry as probes in quality control and dosage form analysis.

Harsh environment fiber optic connectors/testing

NASA Astrophysics Data System (ADS)

Parker, Douglas A.

2014-09-01

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

Adaptive upstream optical power adjustment depending on required power budget in PON access

NASA Astrophysics Data System (ADS)

Yeh, C. H.; Chow, C. W.; Liu, Y. L.

2012-11-01

According to the present passive optical network (PON) standard, the fiber transmission lengths are from 500 m to 20 km between the optical line terminal (OLT) and different optical network units (ONUs). It will result in difference power losses (ΔPloss) from 4 to 5 dB. Hence, we propose to adjust adaptively the output optical power of the upstream laser diode (LD) depending on the different fiber lengths. With the different fiber transmission lengths, we can properly adjust the bias current and modulation index of upstream LD for energy-saving. We characterize and analyze experimentally the relationship of output optical power and modulation amplitude Vamp under different fiber transmissions in PON access. Moreover, due to the adaptive power control of upstream signal, the optical upstream equalization also can be retrieved with power variation of 1.1 dB in this experiment.

Fiber Optic Fabry-Perot Current Sensor Integrated with Magnetic Fluid Using a Fiber Bragg Grating Demodulation

PubMed Central

Xia, Ji; Wang, Qi; Liu, Xu; Luo, Hong

2015-01-01

An optical fiber current sensor based on Fabry-Perot interferometer using a fiber Bragg grating demodulation is proposed. Magnetic fluid is used as a sensitive medium in fiber optical Fabry-Perot (F-P) cavity for the optical characteristic of magnetic-controlled refractive index. A Fiber Bragg grating (FBG) is connected after the F-P interferometer which is used to reflect the optical power at the Bragg wavelength of the interference transmission spectrum. The corresponding reflective power of the FBG will change with different external current intensity, due to the shift on the interference spectrum of the F-P interferometer. The sensing probe has the advantages of convenient measurement for its demodulation, low cost and high current measurement accuracy on account of its sensing structure. Experimental results show that an optimal sensitivity of 0.8522 nw/A and measurement resolution of 0.001 A is obtained with a FBG at 1550 nm with 99% reflectivity. PMID:26184201

Fiber Optic Fabry-Perot Current Sensor Integrated with Magnetic Fluid Using a Fiber Bragg Grating Demodulation.

PubMed

Xia, Ji; Wang, Qi; Liu, Xu; Luo, Hong

2015-07-09

An optical fiber current sensor based on Fabry-Perot interferometer using a fiber Bragg grating demodulation is proposed. Magnetic fluid is used as a sensitive medium in fiber optical Fabry-Perot (F-P) cavity for the optical characteristic of magnetic-controlled refractive index. A Fiber Bragg grating (FBG) is connected after the F-P interferometer which is used to reflect the optical power at the Bragg wavelength of the interference transmission spectrum. The corresponding reflective power of the FBG will change with different external current intensity, due to the shift on the interference spectrum of the F-P interferometer. The sensing probe has the advantages of convenient measurement for its demodulation, low cost and high current measurement accuracy on account of its sensing structure. Experimental results show that an optimal sensitivity of 0.8522 nw/A and measurement resolution of 0.001 A is obtained with a FBG at 1550 nm with 99% reflectivity.

Fiber optic configurations for local area networks

NASA Technical Reports Server (NTRS)

Nassehi, M. M.; Tobagi, F. A.; Marhic, M. E.

1985-01-01

A number of fiber optic configurations for a new class of demand assignment multiple-access local area networks requiring a physical ordering among stations are proposed. In such networks, the data transmission and linear-ordering functions may be distinguished and be provided by separate data and control subnetworks. The configurations proposed for the data subnetwork are based on the linear, star, and tree topologies. To provide the linear-ordering function, the control subnetwork must always have a linear unidirectional bus structure. Due to the reciprocity and excess loss of optical couplers, the number of stations that can be accommodated on a linear fiber optic bus is severely limited. Two techniques are proposed to overcome this limitation. For each of the data and control subnetwork configurations, the maximum number of stations as a function of the power margin, for both reciprocal and nonreciprocal couplers, is computed.

Quantum Zeno Blockade for Next Generation Optical Switching in Fiber Systems

DTIC Science & Technology

2013-09-01

and utilized a self - referential quantum process tomography method to observe the Zeno effect in optical fiber using the ultrafast all- optical switch...controllable and can be used as a knob to study the core physics behind the Zeno-based switching. For this experiment, we developed a self - referential ...efficient optical communications. The quantum Zeno effect can be used to induce or inhibit optical switching through a variety of processes , all of

Coherent fiber supercontinuum for biophotonics

PubMed Central

Tu, Haohua; Boppart, Stephen A.

2013-01-01

Biophotonics and nonlinear fiber optics have traditionally been two independent fields. Since the discovery of fiber-based supercontinuum generation in 1999, biophotonics applications employing incoherent light have experienced a large impact from nonlinear fiber optics, primarily because of the access to a wide range of wavelengths and a uniform spatial profile afforded by fiber supercontinuum. However, biophotonics applications employing coherent light have not benefited from the most well-known techniques of supercontinuum generation for reasons such as poor coherence (or high noise), insufficient controllability, and inadequate portability. Fortunately, a few key techniques involving nonlinear fiber optics and femtosecond laser development have emerged to overcome these critical limitations. Despite their relative independence, these techniques are the focus of this review, because they can be integrated into a low-cost portable biophotonics source platform. This platform can be shared across many different areas of research in biophotonics, enabling new applications such as point-of-care coherent optical biomedical imaging. PMID:24358056

Micro optical fiber light source and sensor and method of fabrication thereof

DOEpatents

Kopelman, Raoul; Tan, Weihong; Shi, Zhong-You

1997-01-01

This invention relates generally to the development of and a method of fabricating a fiber optic micro-light source and sensor (50). An optical fiber micro-light source (50) is presented whose aperture is extremely small yet able to act as an intense light source. Light sources of this type have wide ranging applications, including use as micro-sensors (22) in NSOM. Micro-sensor light sources have excellent detection limits as well as photo stability, reversibility, and millisecond response times. Furthermore, a method for manufacturing a micro optical fiber light source is provided. It involves the photo-chemical attachment of an optically active material onto the end surface of an optical fiber cable which has been pulled to form an end with an extremely narrow aperture. More specifically, photopolymerization has been applied as a means to photo-chemically attach an optically active material (60). This process allows significant control of the size of the micro light source (50). Furthermore, photo-chemically attaching an optically active material (60) enables the implementation of the micro-light source in a variety of sensor applications.

Micro optical fiber light source and sensor and method of fabrication thereof

DOEpatents

Kopelman, Raoul; Tan, Weihong; Shi, Zhong-You

1994-01-01

This invention relates generally to the development of and a method of fabricating a micro optical fiber light source. An optical fiber micro-light source is presented whose aperture is extremely small yet able to act as an intense light source. Light sources of this type have wide ranging applications, including use as micro-sensors in NSOM. Micro-sensor light sources have excellent detection limits as well as photo stability, reversibility, and millisecond response times. Furthermore, a method for manufacturing a micro optical fiber light source is provided. It involves the photo-chemical attachment of an optically active material onto the end surface of an optical fiber cable which has been pulled to form an end with an extremely narrow aperture. More specifically, photopolymerization has been applied as a means to photo-chemically attach an optically active material. This process allows significant control of the size of the micro light source. Furthermore, photo-chemically attaching an optically active material enables the implementation of the micro-light source in a variety of sensor applications.

Micro optical fiber light source and sensor and method of fabrication thereof

DOEpatents

Kopelman, R.; Tan, W.; Shi, Z.Y.

1997-05-06

This invention relates generally to the development of and a method of fabricating a fiber optic micro-light source and sensor. An optical fiber micro-light source is presented whose aperture is extremely small yet able to act as an intense light source. Light sources of this type have wide ranging applications, including use as micro-sensors in NSOM. Micro-sensor light sources have excellent detection limits as well as photo stability, reversibility, and millisecond response times. Furthermore, a method for manufacturing a micro optical fiber light source is provided. It involves the photo-chemical attachment of an optically active material onto the end surface of an optical fiber cable which has been pulled to form an end with an extremely narrow aperture. More specifically, photopolymerization has been applied as a means to photo-chemically attach an optically active material. This process allows significant control of the size of the micro light source. Furthermore, photo-chemically attaching an optically active material enables the implementation of the micro-light source in a variety of sensor applications. 10 figs.

Micro optical fiber light source and sensor and method of fabrication thereof

DOEpatents

Kopelman, R.; Tan, W.; Shi, Z.Y.

1994-11-01

This invention relates generally to the development of and a method of fabricating a micro optical fiber light source. An optical fiber micro-light source is presented whose aperture is extremely small yet able to act as an intense light source. Light sources of this type have wide ranging applications, including use as micro-sensors in NSOM. Micro-sensor light sources have excellent detection limits as well as photo stability, reversibility, and millisecond response times. Furthermore, a method for manufacturing a micro optical fiber light source is provided. It involves the photo-chemical attachment of an optically active material onto the end surface of an optical fiber cable which has been pulled to form an end with an extremely narrow aperture. More specifically, photopolymerization has been applied as a means to photo-chemically attach an optically active material. This process allows significant control of the size of the micro light source. Furthermore, photo-chemically attaching an optically active material enables the implementation of the micro-light source in a variety of sensor applications. 4 figs.

Fiber-Optic Sensor Would Monitor Growth of Polymer Film

NASA Technical Reports Server (NTRS)

Beamesderfer, Michael

2005-01-01

A proposed optoelectronic sensor system would measure the increase in thickness of a film of parylene (a thermoplastic polymer made from para-xylene) during growth of the film in a vapor deposition process. By enabling real-time monitoring of film thickness, the system would make it possible to identify process conditions favorable for growth and to tailor the final thickness of the film with greater precision than is now possible. The heart of the sensor would be a pair of fiber-optic Fabry-Perot interferometers, depicted schematically in the figure. (In principle, a single such interferometer would suffice. The proposal calls for the use of two interferometers for protective redundancy and increased accuracy.) Each interferometer would include a light source, a fiber-optic coupler, and photodetectors in a control box outside the deposition chamber. A single-mode optical fiber for each interferometer would run from inside the control box to a fused-silica faceplate in a sensor head. The sensory tips of the optical fibers would be polished flush with the free surface of the faceplate. In preparation for use, the sensor head would be mounted with a hermetic seal in a feed-through port in the deposition chamber, such that free face of the faceplate and the sensory tips of the optical fibers would be exposed to the deposition environment. During operation, light would travel along each optical fiber from the control box to the sensor head. A small portion of the light would be reflected toward the control box from the end face of each fiber. Once growth of the parylene film started, a small portion of the light would also be reflected toward the control box from the outer surface of the film. In the control box, the two reflected portions of the light beam would interfere in one of the photodetectors. The difference between the phases of the interfering reflected portions of the light beam would vary in proportion to the increasing thickness of the film and the known index of refraction of the film, causing the photodetector reading to vary in proportion to a known sinusoidal function of film thickness. Electronic means of monitoring this variation and the corresponding variation in phase and thickness are well established in the art of interferometry. Hence, by tracking the cumulative change in phase difference from the beginning of deposition, one could track the growing thickness of the film to within a small fraction of a wavelength of light.

Fiber optic evanescent wave biosensor

NASA Astrophysics Data System (ADS)

Duveneck, Gert L.; Ehrat, Markus; Widmer, H. M.

1991-09-01

The role of modern analytical chemistry is not restricted to quality control and environmental surveillance, but has been extended to process control using on-line analytical techniques. Besides industrial applications, highly specific, ultra-sensitive biochemical analysis becomes increasingly important as a diagnostic tool, both in central clinical laboratories and in the doctor's office. Fiber optic sensor technology can fulfill many of the requirements for both types of applications. As an example, the experimental arrangement of a fiber optic sensor for biochemical affinity assays is presented. The evanescent electromagnetic field, associated with a light ray guided in an optical fiber, is used for the excitation of luminescence labels attached to the biomolecules in solution to be analyzed. Due to the small penetration depth of the evanescent field into the medium, the generation of luminescence is restricted to the close proximity of the fiber, where, e.g., the luminescent analyte molecules combine with their affinity partners, which are immobilized on the fiber. Both cw- and pulsed light excitation can be used in evanescent wave sensor technology, enabling the on-line observation of an affinity assay on a macroscopic time scale (seconds and minutes), as well as on a microscopic, molecular time scale (nanoseconds or microseconds).

Nonlinear effects of a modal domain optical fiber sensor in a vibration suppression control loop for a flexible structure

NASA Technical Reports Server (NTRS)

Lindner, D. K.; Zvonar, G. A.; Baumann, W. T.; Delos, P. L.

1993-01-01

Recently, a modal domain optical fiber sensor has been demonstrated as a sensor in a control system for vibration suppression of a flexible cantilevered beam. This sensor responds to strain through a mechanical attachment to the structure. Because this sensor is of the interferometric type, the output of the sensor has a sinusoidal nonlinearity. For small levels of strain, the sensor can be operated in its linear region. For large levels of strain, the detection electronics can be configured to count fringes. In both of these configurations, the sensor nonlinearity imposes some restrictions on the performance of the control system. In this paper we investigate the effects of these sensor nonlinearities on the control system, and identify the region of linear operation in terms of the optical fiber sensor parameters.

The fiber-optic high-speed data bus for a new generation of military aircraft

NASA Astrophysics Data System (ADS)

Uhlhorn, Roger W.

1991-02-01

The avionic suite for the next generation of military aircraft is being designed with component and module commonality in mind in order to control recurring costs and capitalize on economy of scale. The backbone of the suite fashioned out of these modular building blocks is the fiber-optic bit-serial time-division multiplexed high-speed data bus (HSDB), operating at 50 Mb/s, which provides command and control communications among most of the aircraft subsystems and can be used to provide communications for a fly-by-light flight-control system or for the block transfer of data between mass memories and data processors. The fiber-optic HSDB is examined from the top down, beginning with an overview of the evolution of avionic architectures. A review is given of the standardization activity associated with development of the network, the protocols chosen to implement the desired communication functions, configuration options, and the fiber-optic components used in the bus interfaces or other active nodes of the network. It is believed that the utility of the bus extends beyond aircraft to spacecraft, ships, and land vehicles.

Solar Power Satellite (SPS) fiber optic link assessment

NASA Technical Reports Server (NTRS)

1980-01-01

A feasibility demonstration of a 980 MHz fiber optic link for the Solar Power Satellite (SPS) phase reference distribution system was accomplished. A dual fiber-optic link suitable for a phase distribution frequency of 980 MHz was built and tested. The major link components include single mode injection laser diodes, avalanche photodiodes, and multimode high bandwidth fibers. Signal throughput was demonstrated to be stable and of high quality in all cases. For a typical SPS link length of 200 meters, the transmitted phase at 980 MHz varies approximately 2.5 degrees for every deg C of fiber temperature change. This rate is acceptable because of the link length compensation feature of the phase control design.

Sub-mm Scale Fiber Guided Deep/Vacuum Ultra-Violet Optical Source for Trapped Mercury Ion Clocks

NASA Technical Reports Server (NTRS)

Yi, Lin; Burt, Eric A.; Huang, Shouhua; Tjoelker, Robert L.

2013-01-01

We demonstrate the functionality of a mercury capillary lamp with a diameter in the sub-mm range and deep ultraviolet (DUV)/ vacuum ultraviolet (VUV) radiation delivery via an optical fiber integrated with the capillary. DUV spectrum control is observed by varying the fabrication parameters such as buffer gas type and pressure, capillary diameter, electrical resonator design, and temperature. We also show spectroscopic data of the 199Hg+ hyper-fine transition at 40.5GHz when applying the above fiber optical design. We present efforts toward micro-plasma generation in hollow-core photonic crystal fiber with related optical design and theoretical estimations. This new approach towards a more practical DUV optical interface could benefit trapped ion clock developments for future ultra-stable frequency reference and time-keeping applications.

Broadband true time delay for microwave signal processing, using slow light based on stimulated Brillouin scattering in optical fibers.

PubMed

Chin, Sanghoon; Thévenaz, Luc; Sancho, Juan; Sales, Salvador; Capmany, José; Berger, Perrine; Bourderionnet, Jérôme; Dolfi, Daniel

2010-10-11

We experimentally demonstrate a novel technique to process broadband microwave signals, using all-optically tunable true time delay in optical fibers. The configuration to achieve true time delay basically consists of two main stages: photonic RF phase shifter and slow light, based on stimulated Brillouin scattering in fibers. Dispersion properties of fibers are controlled, separately at optical carrier frequency and in the vicinity of microwave signal bandwidth. This way time delay induced within the signal bandwidth can be manipulated to correctly act as true time delay with a proper phase compensation introduced to the optical carrier. We completely analyzed the generated true time delay as a promising solution to feed phased array antenna for radar systems and to develop dynamically reconfigurable microwave photonic filters.

Optical fiber sources and transmission controls for multi-Tb/s systems

NASA Astrophysics Data System (ADS)

Nowak, George Adelbert

The accelerating demand for bandwidth capacity in backbone links of terrestrial communications systems is projected to exceed 1Tb/s by 2002. Lightwave carrier frequencies and fused-silica optical fibers provide the natural combination of high passband frequencies and low- loss medium to satisfy this evolving demand for bandwidth capacity. This thesis addresses three key technologies for enabling multi-Tb/s optical fiber communication systems. The first technology is a broadband source based on supercontinuum generation in optical fiber. Using a single modelocked laser with output pulsewidths of 0.5psec pulses, we generate in ~2m of dispersion-shifted fiber more that 200nm of spectral continuum in the vicinity of 1550nm that is flat to better than +/- 0.5 dB over more than 60nm. The short fiber length prevents degradation of timing jitter of the seed pulses and preserves coherence of the continuum by inhibiting environmental perturbations and mapping of random noise from the vicinity of the input pulse across the continuum. Through experiments and simulations, we find that the continuum characteristics result from 3rd order dispersion effects on higher-order soliton compression. We determine optimal fiber properties to provide desired continuum broadness and flatness for given input pulsewidth and energy conditions. The second technology is a novel delay-shifted nonlinear optical loop mirror (DS-NOLM) that performs a transmission control function by serving as an intensity filter and frequency compensator for <5psec soliton transmission systems. A theoretical and experimental study of the DS-NOLM as a transmission control element in a periodically amplified soliton transmission system is presented. We show that DS-NOLMs enable 4ps soliton transmission over 75km of standard dispersion fiber, with 25km spacing between amplifiers, by filtering the dispersive waves and compensating for Raman-induced soliton self-frequency shift. The third technology is all-fiber wavelength conversion employing induced modulational instability. We obtain wavelength conversion over 40nm with a peak conversion efficiency of 28dB using 600mW pump pulses in 720m of high-nonlinearity optical fiber. We show that the high- nonlinearity fiber enhances the phase-matching bandwidth as well as reducing the required fiber lengths and pump powers.

Nondestructive surface analysis for material research using fiber optic vibrational spectroscopy

NASA Astrophysics Data System (ADS)

Afanasyeva, Natalia I.

2001-11-01

The advanced methods of fiber optical vibrational spectroscopy (FOVS) has been developed in conjunction with interferometer and low-loss, flexible, and nontoxic optical fibers, sensors, and probes. The combination of optical fibers and sensors with Fourier Transform (FT) spectrometer has been used in the range from 2.5 to 12micrometers . This technique serves as an ideal diagnostic tool for surface analysis of numerous and various diverse materials such as complex structured materials, fluids, coatings, implants, living cells, plants, and tissue. Such surfaces as well as living tissue or plants are very difficult to investigate in vivo by traditional FT infrared or Raman spectroscopy methods. The FOVS technique is nondestructive, noninvasive, fast (15 sec) and capable of operating in remote sampling regime (up to a fiber length of 3m). Fourier transform infrared (FTIR) and Raman fiber optic spectroscopy operating with optical fibers has been suggested as a new powerful tool. These techniques are highly sensitive techniques for structural studies in material research and various applications during process analysis to determine molecular composition, chemical bonds, and molecular conformations. These techniques could be developed as a new tool for quality control of numerous materials as well as noninvasive biopsy.

Unusual Attenuation Recovery Process After Fiber Optic Cable Irradiation

NASA Astrophysics Data System (ADS)

Konečná, Z.; Plaček, V.; Havránek, P.

2017-11-01

At present, the number of optical cables in nuclear power plants has been increasing. Fiber optic cables are commonly used at nuclear power plants in instrumentation and control systems but they are usually used in environments without radiation. Nevertheless, currently, the number of applications in NPP containment with radiation is increasing. One of the most prevalent effects of radiation exposure is an increase of signal attenuation (signal loss). This is the result of fiber darkening due to radiation exposure and it is the main limitation factor in application of fiber optics in radiation environment. However, after the irradiation, the fiber optics go through a “recovery process” during which the optical properties improve again; i.e. attenuation decreases. However, we have found cable, where the expected healing process after few days changed its trend and the attenuation increased again to a value well above the attenuation just after the irradiation. This paper describes experiments that were carried out to explain this unusual recovery behaviour.

Controlling formation and suppression of fiber-optical rogue waves.

PubMed

Brée, Carsten; Steinmeyer, Günter; Babushkin, Ihar; Morgner, Uwe; Demircan, Ayhan

2016-08-01

Fiber-optical rogue waves appear as rare but extreme events during optical supercontinuum generation in photonic crystal fibers. This process is typically initiated by the decay of a high-order fundamental soliton into fundamental solitons. Collisions between these solitons as well as with dispersive radiation affect the soliton trajectory in frequency and time upon further propagation. Launching an additional dispersive wave at carefully chosen delay and wavelength enables statistical manipulation of the soliton trajectory in such a way that the probability of rogue wave formation is either enhanced or reduced. To enable efficient control, parameters of the dispersive wave have to be chosen to allow trapping of dispersive radiation in the nonlinear index depression created by the soliton. Under certain conditions, direct manipulation of soliton properties is possible by the dispersive wave. In other more complex scenarios, control is possible via increasing or decreasing the number of intersoliton collisions. The control mechanism reaches a remarkable efficiency, enabling control of relatively large soliton energies. This scenario appears promising for highly dynamic all-optical control of supercontinua.

Latency causes and reduction in optical metro networks

NASA Astrophysics Data System (ADS)

Bobrovs, Vjaceslavs; Spolitis, Sandis; Ivanovs, Girts

2013-12-01

The dramatic growth of transmitted information in fiber optical networks is leading to a concern about the network latency for high-speed reliable services like financial transactions, telemedicine, virtual and augmented reality, surveillance, and other applications. In order to ensure effective latency engineering, the delay variability needs to be accurately monitored and measured, in order to control it. This paper in brief describes causes of latency in fiber optical metro networks. Several available latency reduction techniques and solutions are also discussed, namely concerning usage of different chromatic dispersion compensation methods, low-latency amplifiers, optical fibers as well as other network elements.

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.

Definition, analysis and development of an optical data distribution network for integrated avionics and control systems. Part 2: Component development and system integration

NASA Technical Reports Server (NTRS)

Yen, H. W.; Morrison, R. J.

1984-01-01

Fiber optic transmission is emerging as an attractive concept in data distribution onboard civil aircraft. Development of an Optical Data Distribution Network for Integrated Avionics and Control Systems for commercial aircraft will provide a data distribution network that gives freedom from EMI-RFI and ground loop problems, eliminates crosstalk and short circuits, provides protection and immunity from lightning induced transients and give a large bandwidth data transmission capability. In addition there is a potential for significantly reducing the weight and increasing the reliability over conventional data distribution networks. Wavelength Division Multiplexing (WDM) is a candidate method for data communication between the various avionic subsystems. With WDM all systems could conceptually communicate with each other without time sharing and requiring complicated coding schemes for each computer and subsystem to recognize a message. However, the state of the art of optical technology limits the application of fiber optics in advanced integrated avionics and control systems. Therefore, it is necessary to address the architecture for a fiber optics data distribution system for integrated avionics and control systems as well as develop prototype components and systems.

Apparatus for precision focussing and positioning of a beam waist on a target

NASA Technical Reports Server (NTRS)

Lynch, Dana H. (Inventor); Gunter, William D. (Inventor); Mcalister, Kenneth W. (Inventor)

1991-01-01

The invention relates to optical focussing apparatus and, more particularly, to optical apparatus for focussing a highly collimated Gaussian beam which provides independent and fine control over the focus waist diameter, the focus position both along the beam axis and transverse to the beam, and the focus angle. A beam focussing and positioning apparatus provides focussing and positioning for the waist of a waisted beam at a desired location on a target such as an optical fiber. The apparatus includes a first lens, having a focal plane f sub 1, disposed in the path of an incoming beam and a second lens, having a focal plane f sub 2 and being spaced downstream from the first lens by a distance at least equal to f sub 1 + 10 f sub 2, which cooperates with the first lens to focus the waist of the beam on the target. A rotatable optical device, disposed upstream of the first lens, adjusts the angular orientation of the beam waist. The transverse position of the first lens relative to the axis of the beam is varied to control the transverse position of the beam waist relative to the target (a fiber optic as shown) while the relative axial positions of the lenses are varied to control the diameter of the beam waist and to control the axial position of the beam waist. Mechanical controllers C sub 1, C sub 2, C sub 3, C sub 4, and C sub 5 control the elements of the optical system. How seven adjustments can be made to correctly couple a laser beam into an optical fiber is illustrated. Prior art systems employing optical techniques to couple a laser beam into an optical fiber or other target simply do not provide the seven necessary adjustments. The closest known prior art, a Newport coupler, provides only two of the seven required adjustments.

Applications of telecommunication technology for optical instrumentation with an emphasis on space-time duality

NASA Astrophysics Data System (ADS)

van Howe, James William

Telecommunication technology has often been applied to areas of science and engineering seemingly unrelated to communication systems. Innovations such as electronic amplifiers, the transistor, digital coding, optical fiber, and the laser, which all had roots in communication technology, have been implemented in devices from bar-code scanners to fiber endoscopes for medical procedures. In the same way, the central theme of the work in the following chapters has been to borrow both the concepts and technology of telecommunications systems to develop novel optical instrumentation for non-telecom pursuits. This work particularly leverages fiber-integrated electro-optic phase modulators to apply custom phase profiles to ultrafast pulses for control and manipulation. Such devices are typically used in telecom transmitters to encode phase data onto optical pulses (differential phase-shift keying), or for chirped data transmission. We, however, use electro-optic phase modulators to construct four novel optical devices: (1) a programmable ultrafast optical delay line with record scanning speed for applications in optical metrology, interferometry, or broad-band phase arrays, (2) a multiwavelength pulse generator for real-time optical sampling of electronic waveforms, (3) a simple femtosecond pulse generator for uses in biomedical imaging or ultrafast spectroscopy, and (4) a nonlinear phase compensator to increase the energy of fiber-amplified ultrashort pulse systems. In addition, we describe a fifth instrument which makes use of a higher-order mode fiber, similar in design to dispersion compensating fibers used for telecom. Through soliton self-frequency shift in the higher-order mode fiber, we can broadly-tune the center frequency of ultrashort pulses in energy regimes useful for biomedical imaging or ultrafast spectroscopy. The advantages gained through using telecom components in each of these systems are the simplicity and robustness of all-fiber configurations, high-speed operation, and electronic control of signals. Finally, we devote much attention to the paradigm of space-time duality and temporal imaging which allows the electro-optic phase modulators used in our instrumentation to be framed as temporal analogs of diffractive optical elements such as lenses and prisms. We show how the concepts of "time-lenses" and "time-prisms" give an intuitive understanding of our work as well as insight for the general development of optical instrumentation.

Single optical fiber probe for optogenetics

NASA Astrophysics Data System (ADS)

Falk, Ryan; Habibi, Mohammad; Pashaie, Ramin

2012-03-01

With the advent of optogenetics, all optical control and visualization of the activity of specific cell types is possible. We have developed a fiber optic based probe to control/visualize neuronal activity deep in the brain of awake behaving animals. In this design a thin multimode optical fiber serves as the head of the probe to be inserted into the brain. This fiber is used to deliver excitation/stimulation optical pulses and guide a sample of the emission signal back to a detector. The major trade off in the design of such a system is to decrease the size of the fiber and intensity of input light to minimize physical damage and to avoid photobleaching/phototoxicity but to keep the S/N reasonably high. Here the excitation light, and the associated emission signal, are frequency modulated. Then the output of the detector is passed through a time-lens which compresses the distributed energy of the emission signal and maximizes the instantaneous S/N. By measuring the statistics of the noise, the structure of the time lens can be designed to achieve the global optimum of S/N. Theoretically, the temporal resolution of the system is only limited by the time lens diffraction limit. By adding a second detector, we eliminated the effect of input light fluctuations, imperfection of the optical filters, and back-reflection of the excitation light. We have also designed fibers and micro mechanical assemblies for distributed delivery and detection of light.

Modal domain fiber optic sensor for closed loop vibration control of a flexible beam

NASA Technical Reports Server (NTRS)

Cox, D.; Thomas, D.; Reichard, K.; Lindner, D.; Claus, R. O.

1990-01-01

The use of a modal domain sensor in a vibration control experiment is described. An optical fiber is bonded along the length of a flexible beam. A control signal derived from the output of the modal domain sensor is used to suppress vibrations induced in the beam. A distributed effect model for the modal domain sensor is developed and combined with models of the beam and actuator dynamics to produce a system suitable for control design.

Dynamic optical arbitrary waveform generation with amplitude controlled by interference of two FBG arrays.

PubMed

Zhang, Ailing; Li, Changxiu

2012-10-08

In this paper, a novel structure of dynamic optical arbitrary waveform generation (O-AWG) with amplitude controlled by interference of two fiber Bragg grating (FBG) arrays is proposed. The FBG array consists of several FBGs and fiber stretchers (FSs). The amplitude is controlled by FSs through interference of two FBG arrays. The phase is controlled by FSs simultaneously. As a result, optical pulse trains with various waveforms as well as pulse trains with nonuniform pulse intensity, pulse spacing and pulse width in each period are obtained via FSs adjustment to change the phase shift of signal in each array.

Honeywell optical investigations on FLASH program

NASA Astrophysics Data System (ADS)

O'Rourke, Ken; Peterson, Eric; Yount, Larry

1995-05-01

The increasing performance and reduction of life cycle cost requirements placed on commercial and military transport aircraft are resulting in more complex, highly integrated aircraft control and management systems. The use of fiber optic data transmission media can make significant contributions in achieving these performance and cost goals. The Honeywell portion of Task 2A on the Fly-by-Light Advanced System Hardware (FLASH) program is evaluating a Primary Flight Control System (PFCS) using pilot and copilot inputs from Active Hand Controllers (AHC) which are optically linked to the primary flight Control Computers (PFCC). Customer involvement is an important element of the Task 2A activity. Establishing customer requirements and perspectives on productization of systems developed under FLASH are key to future product success. The Honeywell elements of the PFCS demonstrator provide a command path that is optically interfaced from crew inputs to commands of distributed, smart actuation subsystems commands. Optical communication architectures are implemented using several protocols including the new AS-1773A 20 Mbps data bus standard. The interconnecting fiber optic cable plant is provided by our Task 1A teammate McDonnell Douglas Aerospace (West). Fiber optic cable plant fabrication uses processed, tools and materials reflecting necessary advances in manufacturing required to make fly-by-light avionics systems marketable.

Photogrammetric Verification of Fiber Optic Shape Sensors on Flexible Aerospace Structures

NASA Technical Reports Server (NTRS)

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

2012-01-01

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

Control of operating parameters of laser ceilometers with the application of fiber optic delay line imitation

NASA Astrophysics Data System (ADS)

Kim, A. A.; Klochkov, D. V.; Konyaev, M. A.; Mihaylenko, A. S.

2017-11-01

The article considers the problem of control and verification of the laser ceilometers basic performance parameters and describes an alternative method based on the use of multi-length fiber optic delay line, simulating atmospheric track. The results of the described experiment demonstrate the great potential of this method for inspection and verification procedures of laser ceilometers.

Research on tunable multiwavelength fiber lasers with two-section birefringence fibers and a nonlinear optical loop

NASA Astrophysics Data System (ADS)

Chen, Jiao; Tong, Zhengrong; Zhang, Weihua; Xue, Lifang; Pan, Honggang

2018-05-01

Two types of tunable multiwavelength fiber lasers based on two-section polarization maintaining fibers (PMFs) cascaded/in parallel and nonlinear optical loop are proposed and experimentally demonstrated. Two-section cascaded PMFs and two polarization controllers (PCs) form the two-stage Lyot filter, which can generate comb spectrum to achieve multiwavelength output. When two sections of PMFs are in parallel, PCs in two paths are adjusted to change the beam’s polarization to suppress the light of one branch, and then the light of the other branch passes through the cavity. Additionally, a nonlinear optical loop acts as an intensity-dependent component, which can suppress the mode competition to maintain a stable output of multiwavelength lasing. The nonlinear optical loop is made by a 3 dB coupler, a PC3, and a 200 m high nonlinear fiber. Two types of tunable multiwavelength fiber lasers can achieve tuning of the channel space and the number of lasing wavelengths by adjusting PC1 and PC2. The channel space of the multiwavelengh laser can be tuned at nearly 0.4, 0.68, and 0.92 nm. Meanwhile, the spectral range of multiwavelength lasing can be controlled by PC3 in the nonlinear optical loop, and the tuning range of two multiwavelength lasers is about 2.28 and 1.45 nm, respectively.

Piezoelectroluminescent Optical Fiber Sensor for Diagnostics of the Stress State and Defectoscopy of Composites

NASA Astrophysics Data System (ADS)

Pan'kov, A. A.

2017-05-01

A mathematical model is developed for a piezoelectroluminescent optical fiber pressure sensor is developed in which the mechanoluminescence effect results from the interaction of electroluminescent and piezoelectric coverings put on an optical fiber. The additional control electrodes expand the possibilities of analyzing the distribution of pressure along the fiber. The probability density function of pressure distribution along the sensor is found from results of the measured intensity of light coming from the optical fiber. The problem is reduced to the solution of the Fredholm integral equation of the first kind with a difference kernel depending on the effective parameters of the sensor and properties of an electroluminophor. An algorithm of step-by-step scanning of the nonuniform pressure along the sensor by using the running wave of control voltage is developed. On each step, the amplitude of the wave is increased by a small value, which leads to the appearance of additional luminescence sections of the electroluminophor and the corresponding "glow pulses" at the output of the optical fiber sensor. The sought-for nodal values of pressure and their locations are calculated according to the form of the glow pulses with account of amplitude of the wave at each scanning step. Results of numerical modeling of the process of location of pressure nonuniformities along the sensor by the running wave are found for different scanning steps.

Higher-order micro-fiber modes for Escherichia coli manipulation using a tapered seven-core fiber

PubMed Central

Rong, Qiangzhou; Zhou, Yi; Yin, Xunli; Shao, Zhihua; Qiao, Xueguang

2017-01-01

Optical manipulation using optical micro- and nano-fibers has shown potential for controlling bacterial activities such as E. coli trapping, propelling, and binding. Most of these manipulations have been performed using the propagation of the fundamental mode through the fiber. However, along the maximum mode-intensity axis, the higher-order modes have longer evanescent field extensions and larger field amplitudes at the fiber waist than the fundamental mode, opening up new possibilities for manipulating E. coli bacteria. In this work, a compact seven-core fiber (SCF)-based micro-fiber/optical tweezers was demonstrated for trapping, propelling, and rotating E. coli bacteria using the excitation of higher-order modes. The diameter of the SCF taper was 4 µm at the taper waist, which was much larger than that of previous nano-fiber tweezers. The laser wavelength was tunable from 1500 nm to 1600 nm, simultaneously causing photophoretic force, gradient force, and scattering force. This work provides a new opportunity for better understanding optical manipulation using higher-order modes at the single-cell level. PMID:28966849

Higher-order micro-fiber modes for Escherichia coli manipulation using a tapered seven-core fiber.

PubMed

Rong, Qiangzhou; Zhou, Yi; Yin, Xunli; Shao, Zhihua; Qiao, Xueguang

2017-09-01

Optical manipulation using optical micro- and nano-fibers has shown potential for controlling bacterial activities such as E. coli trapping, propelling, and binding. Most of these manipulations have been performed using the propagation of the fundamental mode through the fiber. However, along the maximum mode-intensity axis, the higher-order modes have longer evanescent field extensions and larger field amplitudes at the fiber waist than the fundamental mode, opening up new possibilities for manipulating E. coli bacteria. In this work, a compact seven-core fiber (SCF)-based micro-fiber/optical tweezers was demonstrated for trapping, propelling, and rotating E. coli bacteria using the excitation of higher-order modes. The diameter of the SCF taper was 4 µm at the taper waist, which was much larger than that of previous nano-fiber tweezers. The laser wavelength was tunable from 1500 nm to 1600 nm, simultaneously causing photophoretic force, gradient force, and scattering force. This work provides a new opportunity for better understanding optical manipulation using higher-order modes at the single-cell level.

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.

Wide-area-distributed storage system for a multimedia database

NASA Astrophysics Data System (ADS)

Ueno, Masahiro; Kinoshita, Shigechika; Kuriki, Makato; Murata, Setsuko; Iwatsu, Shigetaro

1998-12-01

We have developed a wide-area-distribution storage system for multimedia databases, which minimizes the possibility of simultaneous failure of multiple disks in the event of a major disaster. It features a RAID system, whose member disks are spatially distributed over a wide area. Each node has a device, which includes the controller of the RAID and the controller of the member disks controlled by other nodes. The devices in the node are connected to a computer, using fiber optic cables and communicate using fiber-channel technology. Any computer at a node can utilize multiple devices connected by optical fibers as a single 'virtual disk.' The advantage of this system structure is that devices and fiber optic cables are shared by the computers. In this report, we first described our proposed system, and a prototype was used for testing. We then discussed its performance; i.e., how to read and write throughputs are affected by data-access delay, the RAID level, and queuing.

New Submerged-Robot Control Optical Fiber Cable With Small-Diameter, High-Strength Frp Covered Optical Fiber

NASA Astrophysics Data System (ADS)

Fuse, K.; Shirasaka, Y.; Yanagawa, H.

1984-10-01

Of natural resources on the earth, the utilization of the oceans has the oldest history, and the development of them has been delayed most. However, hot expectation is being placed on the development of the oceans. The element that obstructs the acceleration of such development is the sea itself. From a technical viewpoint, the means to explore the oceans have not been developed sufficiently, and equipment such as special large vehicles and ships has been bulky, requiring a very large sum of money to prepare them. These have been part of the reasons why the development of the oceans has been delayed. For this reason, a large number of exploratory systems will be studied as the ocean development becomes active in the near future. A single optical fiber cable has been considered as a cable for control of an ocean exploratory robot, which weighs approximately 30 to 40 kg at most in air requiring no power feeding to the drive section inside the vehicle and running by self on a built-in battery, as well as for data transfer. This cable is believed most suitable in terms of high speed mobility, transmission characteristics, and system cost. The mode (system) of pay off of the cable paid off by the ship loading such a cable becomes very important in the design of optical fiber cables for control of ocean exploratory robots. This paper introduces a new FRP covered optical fiber cable developed as an optical fiber cable for control of ocean exploratory robots with a small diameter and rotating motion. This cable is considered most suitable for the pay off-system which is simple and offers the highest space utility. The paper describes a basic study made prior to an actual performance test in the sea, as well as its design and characteristics.

Spectrum-modulating fiber-optic sensors for aircraft control systems

NASA Technical Reports Server (NTRS)

Beheim, Glenn; Fritsch, Klaus

1987-01-01

A family of fiber-optic sensors for aircraft engine control systems is described. Each of these sensors uses a spectrum-modulation method to obtain an output which is largely independent of the fiber link transmissivity. A position encoder is described which uses a code plate to digitally modulate the sensor output spectrum. Also described are pressure and temperature sensors, each of which uses a Fabry-Perot cavity to modulate the sensor output spectrum as a continuous function of the measurand. A technique is described whereby a collection of these sensors may be effectively combined to perform a number of the measurements which are required by an aircraft-engine control system.

Deep learning and model predictive control for self-tuning mode-locked lasers

NASA Astrophysics Data System (ADS)

Baumeister, Thomas; Brunton, Steven L.; Nathan Kutz, J.

2018-03-01

Self-tuning optical systems are of growing importance in technological applications such as mode-locked fiber lasers. Such self-tuning paradigms require {\\em intelligent} algorithms capable of inferring approximate models of the underlying physics and discovering appropriate control laws in order to maintain robust performance for a given objective. In this work, we demonstrate the first integration of a {\\em deep learning} (DL) architecture with {\\em model predictive control} (MPC) in order to self-tune a mode-locked fiber laser. Not only can our DL-MPC algorithmic architecture approximate the unknown fiber birefringence, it also builds a dynamical model of the laser and appropriate control law for maintaining robust, high-energy pulses despite a stochastically drifting birefringence. We demonstrate the effectiveness of this method on a fiber laser which is mode-locked by nonlinear polarization rotation. The method advocated can be broadly applied to a variety of optical systems that require robust controllers.

Novel adaptive fiber-optics collimator for coherent beam combination.

PubMed

Zhi, Dong; Ma, Pengfei; Ma, Yanxing; Wang, Xiaolin; Zhou, Pu; Si, Lei

2014-12-15

In this manuscript, we experimentally validate a novel design of adaptive fiber-optics collimator (AFOC), which utilizes two levers to enlarge the movable range of the fiber end cap. The enlargement of the range makes the new AFOC possible to compensate the end-cap/tilt aberration in fiber laser beam combining system. The new AFOC based on flexible hinges and levers was fabricated and the performance of the new AFOC was tested carefully, including its control range, frequency response and control accuracy. Coherent beam combination (CBC) of two 5-W fiber amplifiers array with simultaneously end-cap/tilt control and phase-locking control was implemented successfully with the novel AFOC. Experimental results show that the average normalized power in the bucket (PIB) value increases from 0.311 to 0.934 with active phasing and tilt aberration compensation simultaneously, and with both controls on, the fringe contrast improves to more than 82% from 0% for the case with both control off. This work presents a promising structure for tilt aberration control in high power CBC system.

Design of a fiber-optic interrogator module for telecommunication satellites

NASA Astrophysics Data System (ADS)

Putzer, Philipp; Koch, Alexander W.; Plattner, Markus; Hurni, Andreas; Manhart, Markus

2017-11-01

In this paper we present the results of the radiation tests performed on the optical components of the fiber-optic interrogator module as a part of the Hybrid Sensor Bus (HSB) system. The HSB-system is developed in the frame of an ESAARTES program and will be verified as flight demonstrator onboard the German Heinrich Hertz satellite in 2016. The HSB system is based on a modular concept which includes sensor interrogation modules based on I2C electrical and fiber Bragg grating (FBG) fiber-optical sensor elements. Onboard fiber-optic sensing allows the implementation of novel control and monitoring methods. For read-out of multiple FBG sensors, a design based on a tunable laser diode as well as a design based on a spectrometer is considered. The expected and tested total ionizing dose (TID) applicable to the HSB system is in the range between 100 krad and 300 krad inside the satellite in the geostationary orbit over a life time of 15 years. We present radiation test results carried out on critical optical components to be used in the fiber-optic interrogation module. These components are a modulated grating Y-branch (MGY) tunable laser diode acting as light source for the tuning laser approach, the line detector of a spectrometer, photodetectors and the FBG sensors acting as sensor elements. A detailed literature inquiry of radiation effects on optical fibers and FBG sensors, is also included in the paper. The fiber-optic interrogator module implemented in the HSB system is based on the most suitable technology, which sustains the harsh environment in the geostationary orbit.

Optical Closed-Loop Propulsion Control System Development

NASA Technical Reports Server (NTRS)

Poppel, Gary L.

1998-01-01

The overall objective of this program was to design and fabricate the components required for optical closed-loop control of a F404-400 turbofan engine, by building on the experience of the NASA Fiber Optic Control System Integration (FOCSI) program. Evaluating the performance of fiber optic technology at the component and system levels will result in helping to validate its use on aircraft engines. This report includes descriptions of three test plans. The EOI Acceptance Test is designed to demonstrate satisfactory functionality of the EOI, primarily fail-safe throughput of the F404 sensor signals in the normal mode, and validation, switching, and output of the five analog sensor signals as generated from validated optical sensor inputs, in the optical mode. The EOI System Test is designed to demonstrate acceptable F404 ECU functionality as interfaced with the EOI, making use of a production ECU test stand. The Optical Control Engine Test Request describes planned hardware installation, optical signal calibrations, data system coordination, test procedures, and data signal comparisons for an engine test demonstration of the optical closed-loop control.

Combined effects of nonparaxiality, optical activity, and walk-off on rogue wave propagation in optical fibers filled with chiral materials.

PubMed

Temgoua, D D Estelle; Tchokonte, M B Tchoula; Kofane, T C

2018-04-01

The generalized nonparaxial nonlinear Schrödinger (NLS) equation in optical fibers filled with chiral materials is reduced to the higher-order integrable Hirota equation. Based on the modified Darboux transformation method, the nonparaxial chiral optical rogue waves are constructed from the scalar model with modulated coefficients. We show that the parameters of nonparaxiality, third-order dispersion, and differential gain or loss term are the main keys to control the amplitude, linear, and nonlinear effects in the model. Moreover, the influence of nonparaxiality, optical activity, and walk-off effect are also evidenced under the defocusing and focusing regimes of the vector nonparaxial NLS equations with constant and modulated coefficients. Through an algorithm scheme of wider applicability on nonparaxial beam propagation methods, the most influential effect and the simultaneous controllability of combined effects are underlined, showing their properties and their potential applications in optical fibers and in a variety of complex dynamical systems.

Combined effects of nonparaxiality, optical activity, and walk-off on rogue wave propagation in optical fibers filled with chiral materials

NASA Astrophysics Data System (ADS)

Temgoua, D. D. Estelle; Tchokonte, M. B. Tchoula; Kofane, T. C.

2018-04-01

The generalized nonparaxial nonlinear Schrödinger (NLS) equation in optical fibers filled with chiral materials is reduced to the higher-order integrable Hirota equation. Based on the modified Darboux transformation method, the nonparaxial chiral optical rogue waves are constructed from the scalar model with modulated coefficients. We show that the parameters of nonparaxiality, third-order dispersion, and differential gain or loss term are the main keys to control the amplitude, linear, and nonlinear effects in the model. Moreover, the influence of nonparaxiality, optical activity, and walk-off effect are also evidenced under the defocusing and focusing regimes of the vector nonparaxial NLS equations with constant and modulated coefficients. Through an algorithm scheme of wider applicability on nonparaxial beam propagation methods, the most influential effect and the simultaneous controllability of combined effects are underlined, showing their properties and their potential applications in optical fibers and in a variety of complex dynamical systems.

Phase shifting interferometry based on a vibration sensor - feasibility study on elimination of the depth degeneracy

NASA Astrophysics Data System (ADS)

Lee, Seung Seok; Kim, Ju Ha; Choi, Eun Seo

2017-04-01

We proposed novel phase-shifting interferometry using a fiber-optic vibration sensor. The Doppler shift in the coiled fiber caused by vibrations can be used to detect the vibrations by using a fiber-optic interferometer. The principle can be applied to induce phase shifts. While applying vibrations to the coiled fiber at various vibration frequencies, we recorded the variations in the interference fringes. The interference fringe moved to longer wavelengths when a vibration frequency was increased from 38.00 to 38.40 kHz. Phase variations of 3.59 rad/kHz were obtained. The ability to accurately control the phase by using the vibrations in the coiled fiber was demonstrated by the elimination of the depth degeneracy using the complex signal generated by the phase-shifted interference fringes. Using vibrations to control phase shifting can be an acceptable alternative to conventional methods and can be applied to resolve the depth ambiguity in Fourier domain optical coherence tomography.

Fiber optical sensing on-board communication satellites

NASA Astrophysics Data System (ADS)

Hurni, A.; Lemke, N. M. K.; Roner, M.; Obermaier, J.; Putzer, P.; Kuhenuri Chami, N.

2017-11-01

Striving constantly to reduce mass, AIT effort and overall cost of the classical point-to-point wired temperature sensor harness on-board telecommunication satellites, OHB System (formerly Kayser-Threde) has introduced the Hybrid Sensor Bus (HSB) system. As a future spacecraft platform element, HSB relies on electrical remote sensor units as well as fiber-optical sensors, both of which can serially be connected in a bus architecture. HSB is a modular measurement system with many applications, also thanks to the opportunities posed by the digital I²C bus. The emphasis, however, is on the introduction of fiber optics and especially fiber-Bragg grating (FBG) temperature sensors as disruptive innovation for the company's satellite platforms. The light weight FBG sensors are directly inscribed in mechanically robust and radiation tolerant fibers, reducing the need for optical fiber connectors and splices to a minimum. Wherever an FBG sensor shall be used, the fiber is glued together with a corresponding temperature transducer to the satellites structure or to a subsystem. The transducer is necessary to provide decoupling of mechanical stress, but simultaneously ensure a high thermal conductivity. HSB has been developed in the frame of an ESA-ARTES program with European and German co-funding and will be verified as flight demonstrator on-board the German Heinrich Hertz satellite (H2Sat). In this paper the Engineering Model development of HSB is presented and a Fiber-optical Sensor Multiplexer for a more flexible sensor bus architecture is introduced. The HSB system aims at telecommunication satellite platforms with an operational life time beyond 15 years in geostationary orbit. It claims a high compatibility in terms of performance and interfaces with existing platforms while it was designed with future applications with increased radiation exposure already in mind. In its basic configuration HSB consists of four modules which are the Power Supply Unit, the HSB Controller Module, the Interrogator Controller Module and the Analog Front-End for the fiber-optical interrogation. The Interrogator Controller Module handles both, the electrical and fiber-optical sensor network. For the latter it is to be completed by the Analog Front-End. On this front-end, a tunable laser diode is implemented for the scanning of the FBG sensors. The reflected spectra are measured on multiple fiber channels and are then evaluated by use of a peak detection algorithm in order to obtain a precise temperature measurement. The precise operation of the photonic system on long terms can be guaranteed thanks to an inorbit calibration concept.

Variable photonic crystal fiber optical attenuator combining air hole reduction induced radiation and bending loss

NASA Astrophysics Data System (ADS)

Yokota, Hirohisa; Sano, Tomohiko; Imai, Yoh

2018-06-01

Recently, an optical attenuator has been important in fiber optic communication systems, because a transmission power in fiber has become higher due to a channel increment in wavelength division multiplexing transmission. A photonic crystal fiber (PCF) optical attenuator is fabricated by air hole diameter reduction in a part of PCF in which radiations are caused in the air hole diameter reduced part of PCF. A PCF optical attenuator has a high power resistance feature due to its radiation-induced operation of optical attenuation. In this paper, we proposed a variable PCF optical attenuator in which a bend was applied to the air hole diameter reduced part in PCF optical attenuator that was fabricated by CO2 laser irradiation. In PCF optical attenuator fabrication, the attenuation was adjusted by the reduced air hole diameter with laser irradiation time control. It was demonstrated that 10.6-13.5 dB of variable attenuation was obtained at 1550 nm-wavelength with 0°-90° bending angle applied to the air hole diameter reduced part in PCF optical attenuator.

Variable photonic crystal fiber optical attenuator combining air hole reduction induced radiation and bending loss

NASA Astrophysics Data System (ADS)

Yokota, Hirohisa; Sano, Tomohiko; Imai, Yoh

2018-02-01

Recently, an optical attenuator has been important in fiber optic communication systems, because a transmission power in fiber has become higher due to a channel increment in wavelength division multiplexing transmission. A photonic crystal fiber (PCF) optical attenuator is fabricated by air hole diameter reduction in a part of PCF in which radiations are caused in the air hole diameter reduced part of PCF. A PCF optical attenuator has a high power resistance feature due to its radiation-induced operation of optical attenuation. In this paper, we proposed a variable PCF optical attenuator in which a bend was applied to the air hole diameter reduced part in PCF optical attenuator that was fabricated by CO2 laser irradiation. In PCF optical attenuator fabrication, the attenuation was adjusted by the reduced air hole diameter with laser irradiation time control. It was demonstrated that 10.6-13.5 dB of variable attenuation was obtained at 1550 nm-wavelength with 0°-90° bending angle applied to the air hole diameter reduced part in PCF optical attenuator.

Lamping process and application of ultra small U-shaped, whispery gallery mode (WGM) based optic fiber sensors

NASA Astrophysics Data System (ADS)

Chang, Yuan Cheng; Chiang, Chia Chin

2015-07-01

This study success to smaller and control the diameter of single mode optical fiber whispery gallery mode (WGM) to diameter 0.8 mm nonetching and nontaping treated. The sensitivity of this type ultra-small U-shape WGM strengthens neither etching nor taping fibre. The sensitivity we apply to thermo test depends on wavelength shift from 40 ~ 96°C (R2 = 0.99 ). The specially characteristics of the optical fiber could be tested for temperature, refraction, vibration, concussion, and CO2 detection.

Optical interconnection for a polymeric PLC device using simple positional alignment.

PubMed

Ryu, Jin Hwa; Kim, Po Jin; Cho, Cheon Soo; Lee, El-Hang; Kim, Chang-Seok; Jeong, Myung Yung

2011-04-25

This study proposes a simple cost-effective method of optical interconnection between a planar lightwave circuit (PLC) device chip and an optical fiber. It was conducted to minimize and overcome the coupling loss caused by lateral offset which is due to the process tolerance and the dimensional limitation existing between PLC device chips and fiber array blocks with groove structures. A PLC device chip and a fiber array block were simultaneously fabricated in a series of polymer replication processes using the original master. The dimensions (i.e., width and thickness) of the under-clad of the PLC device chip were identical to those of the fiber array block. The PLC device chip and optical fiber were aligned by simple positional control for the vertical direction of the PLC device chip under a particular condition. The insertion loss of the proposed 1 x 2 multimode optical splitter device interconnection was 4.0 dB at 850 nm and the coupling loss was below 0.1 dB compared with single-fiber based active alignment.

HT/HP x-tree and downhole fiber optic connectors and their use on subsea intelligent wells

NASA Astrophysics Data System (ADS)

Wright, Perry; Barlow, Stewart

2004-12-01

Offshore Oil and Gas R&D has been committed to improved reservoir performance through production monitoring. Technology improvements in these areas offer the greatest potential returns through increased knowledge of the reservoir, and the improvements in real-time production control that the technology and knowledge base can provide. One area of technology that supports this development is the growing application of fiber optic sensors for reservoir and production monitoring. These sensors cannot function in isolation, and need support in the form of fiber optic connection systems for x-tree penetrations. ODI have been developing products for fiber optic tree penetrations and down-hole wet connections for the last 4 years, working with Intelligent Wells Group at BP America Production Company in Houston. This paper discusses the application and reliability of fiber optic connectors, and reviews the development of the ODI I-CONN connection system and its application for vertical and horizontal x-trees, work-over systems and running tools, and down-hole systems.

Fabrication and optical characterization of silica optical fibers containing gold nanoparticles.

PubMed

de Oliveira, Rafael E P; Sjödin, Niclas; Fokine, Michael; Margulis, Walter; de Matos, Christiano J S; Norin, Lars

2015-01-14

Gold nanoparticles have been used since antiquity for the production of red-colored glasses. More recently, it was determined that this color is caused by plasmon resonance, which additionally increases the material's nonlinear optical response, allowing for the improvement of numerous optical devices. Interest in silica fibers containing gold nanoparticles has increased recently, aiming at the integration of nonlinear devices with conventional optical fibers. However, fabrication is challenging due to the high temperatures required for silica processing and fibers with gold nanoparticles were solely demonstrated using sol-gel techniques. We show a new fabrication technique based on standard preform/fiber fabrication methods, where nanoparticles are nucleated by heat in a furnace or by laser exposure with unprecedented control over particle size, concentration, and distribution. Plasmon absorption peaks exceeding 800 dB m(-1) at 514-536 nm wavelengths were observed, indicating higher achievable nanoparticle concentrations than previously reported. The measured resonant nonlinear refractive index, (6.75 ± 0.55) × 10(-15) m(2) W(-1), represents an improvement of >50×.

Manufacturing Methods and Technology Program for Ruggedized Tactical Fiber Optic Cable.

DTIC Science & Technology

1979-10-26

cores manufactured on this unit since the improvements were incorporated. An automatic diameter control unit with a laser micrometer sensor has been...fiber optic sensor systems for the TACA-MO aircraft and power encoding, an 18-port single fiber data bus for the Autonetics information transfer...echnica del Estado, Santiago, Chile in 1958. He received a degree in Industrial Chemical Engineering from Escuela de Ingenieros Industriales , Santiago

Fiber-linked interferometric pressure sensor

NASA Technical Reports Server (NTRS)

Beheim, G.; Fritsch, K.; Poorman, R. N.

1987-01-01

A fiber-optic pressure sensor is described which uses a diaphragm to modulate the mirror separation of a Fabry-Perot cavity (the sensing cavity). A multimode optical fiber delivers broadband light to the sensing cavity and returns the spectrally modulated light which the cavity reflects. The sensor's output spectrum is analyzed using a tunable Fabry-Perot cavity (the reference cavity) to determine the mismatch in the mirror separations of the two cavities. An electronic servo control uses this result to cause the mirror separation of the reference cavity to equal that of the sensing cavity. The displacement of the pressure-sensing diaphragm is then obtained by measuring the capacitance of the reference cavity's metal-coated mirrors. Relative to other fiber-optic sensors, an important advantage of this instrument is its high immunity to the effects of variations in both the transmissivity of the fiber link and the wavelength of the optical source.

Photonic jet etching: Justifying the shape of optical fiber tip

NASA Astrophysics Data System (ADS)

Abdurrochman, Andri; Zelgowski, Julien; Lecler, Sylvain; Mermet, Frédéric; Tumbelaka, Bernard; Fontaine, Joël

2016-02-01

Photonic jet (PJ) is a low diverging and highly concentrated beam in the shadow side of dielectric particle (cylinder or sphere). The concentration can be more than 200 times higher than the incidence wave. It is a non-resonance phenomenon in the near-field can propagate in a few wavelengths. Many potential applications have been proposed, including PJ etching. Hence, a guided-beam is considered increasing the PJ mobility control. While the others used a combination of classical optical fibers and spheres, we are concerned on a classical optical fiber with spherical tip to generate the PJ. This PJ driven waveguide has been realized using Gaussian mode beam inside the core. It has different variable parameters compared to classical PJ, which will be discussed in correlation with the etching demonstrations. The parameters dependency between the tip and PJ properties are complex; and theoretical aspect of this interaction will be exposed to justify the shape of our tip and optical fiber used in our demonstrations. Methods to achieve such a needed optical fiber tip will also be described. Finally the ability to generate PJ out of the shaped optical fiber will be experimentally demonstrated and the potential applications for material processing will be exposed.

Fibercore AstroGain fiber: multichannel erbium doped fibers for optical space communications

NASA Astrophysics Data System (ADS)

Hill, Mark; Gray, Rebecca; Hankey, Judith; Gillooly, Andy

2014-03-01

Fibercore have developed AstroGainTM fiber optimized for multichannel amplifiers used in optical satellite communications and control. The fiber has been designed to take full advantage of the photo-annealing effect that results from pumping in the 980nm region. The proprietary trivalent structure of the core matrix allows optimum recovery following radiation damage to the fiber, whilst also providing a market leading Erbium Doped Fiber Amplifier (EDFA) efficiency. Direct measurements have been taken of amplifier efficiency in a multichannel assembly, which show an effective photo-annealing recovery of up to 100% of the radiation induced attenuation through excitation of point defects.

Ultrafast nonlinear optofluidics in selectively liquid-filled photonic crystal fibers.

PubMed

Vieweg, M; Gissibl, T; Pricking, S; Kuhlmey, B T; Wu, D C; Eggleton, B J; Giessen, H

2010-11-22

Selective filling of photonic crystal fibers with different media enables a plethora of possibilities in linear and nonlinear optics. Using two-photon direct-laser writing we demonstrate full flexibility of individual closing of holes and subsequent filling of photonic crystal fibers with highly nonlinear liquids. We experimentally demonstrate solitonic supercontinuum generation over 600 nm bandwidth using a compact femtosecond oscillator as pump source. Encapsulating our fibers at the ends we realize a compact ultrafast nonlinear optofluidic device. Our work is fundamentally important to the field of nonlinear optics as it provides a new platform for investigations of spatio-temporal nonlinear effects and underpins new applications in sensing and communications. Selective filling of different linear and nonlinear liquids, metals, gases, gain media, and liquid crystals into photonic crystal fibers will be the basis of new reconfigurable and versatile optical fiber devices with unprecedented performance. Control over both temporal and spatial dispersion as well as linear and nonlinear coupling will lead to the generation of spatial-temporal solitons, so-called optical bullets.

77 FR 73456 - Notice of Intent To Grant Exclusive Patent License; Fiber Optic Sensor Systems Technology...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-10

...; Fiber Optic Sensor Systems Technology Corporation AGENCY: Department of the Navy, DoD. ACTION: Notice... Systems Technology Corporation a revocable, nonassignable, exclusive license to practice the field of use of electrical power measurements for the measurement or control of temperature, pressure, strain...

75 FR 34988 - Notice of Intent To Grant Exclusive Patent License; Fiber Optic Sensor Systems Technology...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-21

...; Fiber Optic Sensor Systems Technology Corporation AGENCY: Department of the Navy, DoD. ACTION: Notice... Systems Technology Corporation a revocable, nonassignable, exclusive license to practice the field of use of electrical power measurements for the measurement or control of temperature, pressure, strain...

Soil temperature variability in complex terrain measured using fiber-optic distributed temperature sensing

USDA-ARS?s Scientific Manuscript database

Soil temperature (Ts) exerts critical controls on hydrologic and biogeochemical processes but magnitude and nature of Ts variability in a landscape setting are rarely documented. Fiber optic distributed temperature sensing systems (FO-DTS) potentially measure Ts at high density over a large extent. ...

Modular separation-based fiber-optic sensors for remote in situ monitoring.

PubMed

Dickens, J; Sepaniak, M

2000-02-01

A modular separation-based fiber-optic sensor (SBFOS) with an integrated electronically controlled injection device is described for potential use in remote environmental monitoring. An SBFOS is a chemical monitor that integrates the separation selectivity and versatility afforded by capillary electrophoresis with the remote and high sensitivity capabilities of fiber-optic-based laser-induced fluorescence sensing. The detection module of the SBFOS accommodates all essential sensing components for dual-optical fiber, on-capillary fluorescence detection. An injection module, similar to injection platforms on micro-analysis chips, is also integrated to the SBFOS. The injection module allows for electronically controlled injection of the sample onto the separation capillary. The design and operational characteristics of the modular SBFOS are discussed in this paper. A micellar electrokinetic capillary chromatography mode of separation is employed to evaluate the potential of the sensor for in situ monitoring of neutral toxins (aflatoxins). The analytical figures of merit for the modular SBFOS include analysis times of between 5 and 10 min, separation efficiencies of approximately 10(4) theoretical plates, detection limits for aflatoxins in the mid-to-low nanomolar range, and controllable operation that results in sensor performance that is largely immune to sample matrix effects.

Femtosecond laser inscription of optical circuits in the cladding of optical fibers

NASA Astrophysics Data System (ADS)

Grenier, Jason R.

The aim of this dissertation was to address the question of whether the cladding of single-mode fibers (SMFs) could be modified to enable optical fibers to serve as a more integrated, highly functional platform for optical circuit devices that can efficiently interconnect with the pre-existing fiber core waveguide. The approach adopted in this dissertation was to employ femtosecond laser direct writing (FLDW), an inherently 3D fabrication technique that harnesses non-linear laser-material interactions to modify the fused silica fiber cladding. A fiber mounting and alignment technique was developed along with oil-immersion focusing to address the strong aberrations caused by the cylindrical fiber shape. The development of real-time device monitoring during the FLDW was instrumental to overcome the acute coupling sensitivity to laser alignment errors of +/-1 ?m positional uncertainty, and thereby opened a new practical direction for the precise fabrication of optical devices inside optical fibers. These powerful and flexible laser fabrication and characterization techniques were successfully employed to optimize optical waveguiding devices positioned within the core and cladding of optical fibers. X-, S-Bend, and directional couplers were developed to enable efficient coupling between the laser-formed cladding devices and the pre-existing core waveguide, enabling up to 62% power transfer over bandwidths up to 300 nm at telecommunication wavelengths. Precise alignment of femtosecond laser modification tracks were positioned inside or near the core waveguide of SMFs was further shown to enable a flexible reshaping of the optical properties to create multimode guiding sections arbitrarily along the fiber length. This core waveguide modification facilitated the precise formation of multimode interferometers along the core waveguide to precisely tailor the modal profiles, and control the spectral and polarization response. In-fiber multimode interference (MMI) splitters and couplers were fabricated with coupling ratios from 2% to 50% over a broad 350 nm bandwidth across the telecommunication band. Laser-induced birefringence was harnessed to generate polarization dependent MMI devices for strong polarization filtering (24 dB isolation), or polarization selective taps with up to 50% tapping efficiency over a 25 nm bandwidth. This dissertation is therefore the first demonstration of femtosecond laser direct writing as a flexible and monolithic means of embedding and integrating highly functional optical circuit devices within the cladding of optical fibers that can interconnect efficiently with the pre-existing fiber core waveguide. These developments represent a significant technological advancement for creating new 3D photonic integrated microsystems within the cladding of optical fibers and underpins a new technological platform of fiber cladding photonics.

Fiberoptics for propulsion control system

NASA Technical Reports Server (NTRS)

Baumbick, R. J.

1984-01-01

In aircraft systems with digital controls, fiberoptics has advantages over wire systems because of its inherent immunity to electromagnetic noise (EMI) and electromagnetic pulses (EMP). It also offers a weight benefit when metallic conductors are replaced by optical fibers. To take full advantage of the benefits of optical waveguides, passive optical sensors are also being developed to eliminate the need for electrical power to the sensor. Fiberoptics may also be used for controlling actuators on engine and airframe. In this application, the optical fibers, connectors, etc. will be subjected to high temperature and vibrations. This paper discussed the use of fiberoptics in aircraft propulsion systems together with the optical sensors and optically controlled actuators being developed to take full advantage of the benefits which fiberoptics offers. The requirements for sensors and actuators in advanced propulsion systems are identified. The benefits of using fiberoptics in place of conventional wire systems are discussed as well as the environmental conditions under which the optical components must operate.

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.

Optical fiber sensors embedded in flexible polymer foils

NASA Astrophysics Data System (ADS)

van Hoe, Bram; van Steenberge, Geert; Bosman, Erwin; Missinne, Jeroen; Geernaert, Thomas; Berghmans, Francis; Webb, David; van Daele, Peter

2010-04-01

In traditional electrical sensing applications, multiplexing and interconnecting the different sensing elements is a major challenge. Recently, many optical alternatives have been investigated including optical fiber sensors of which the sensing elements consist of fiber Bragg gratings. Different sensing points can be integrated in one optical fiber solving the interconnection problem and avoiding any electromagnetical interference (EMI). Many new sensing applications also require flexible or stretchable sensing foils which can be attached to or wrapped around irregularly shaped objects such as robot fingers and car bumpers or which can even be applied in biomedical applications where a sensor is fixed on a human body. The use of these optical sensors however always implies the use of a light-source, detectors and electronic circuitry to be coupled and integrated with these sensors. The coupling of these fibers with these light sources and detectors is a critical packaging problem and as it is well-known the costs for packaging, especially with optoelectronic components and fiber alignment issues are huge. The end goal of this embedded sensor is to create a flexible optical sensor integrated with (opto)electronic modules and control circuitry. To obtain this flexibility, one can embed the optical sensors and the driving optoelectronics in a stretchable polymer host material. In this article different embedding techniques for optical fiber sensors are described and characterized. Initial tests based on standard manufacturing processes such as molding and laser structuring are reported as well as a more advanced embedding technique based on soft lithography processing.

Design and optimization of broadband tapered optical fibers with a nanofiber waist.

PubMed

Stiebeiner, Ariane; Garcia-Fernandez, Ruth; Rauschenbeutel, Arno

2010-10-25

The control over the transmission properties of tapered optical fibers (TOFs) is an important requirement for a whole range of applications. Using a carefully designed flame pulling process that allows us to realize preset fiber radius profiles, we fabricate TOFs with a nanofiber waist. We study the spectral transmission properties of these TOFs as a function of the taper profile and the waist length and show how the transmission band of the TOF can be tuned via different fiber profile parameters. Based on these results, we have designed a nanofiber-waist TOF with broadband transmission for surface spectroscopy of organic molecules. Moreover, our method allows us to analyze the loss mechanisms of optical nanofibers.

Transients control in Raman fiber amplifiers

NASA Astrophysics Data System (ADS)

Freitas, Marcio; Givigi, Sidney N., Jr.; Klein, Jackson; Calmon, Luiz C.; de Almeida, Ailson R.

2004-11-01

Raman fiber amplifiers (RFA) are being used in optical transmission communication systems in the recent years due to their advantages in comparison to erbium-doped fiber amplifiers (EDFA). Recently the analysis of RFAs dynamic response and transients control has become important in order to predict the system response to add/drop of channels or cable cuts in optical systems, and avoid impairments caused by the power transients. Fast signal power transients in the surviving channels are caused by the cross-gain saturation effect in RFA and the slope of the gain saturation characteristics determines the steady-state surviving channel power excursion. We are presenting the modeling and analysis of power transients and its control using a pump control method for a single and multi-pump scheme.

Optical Sensors Based on Single Arm Thin Film Waveguide Interferometer

NASA Technical Reports Server (NTRS)

Sarkisov, Sergey S.

1997-01-01

All the goals of the research effort for the first year were met by the accomplishments. Additional efforts were done to speed up the process of development and construction of the experimental gas chamber which will be completed by the end of 1997. This chamber incorporates vacuum sealed multimode optical fiber lines which connect the sensor to the remote light source and signal processing equipment. This optical fiber line is a prototype of actual optical communication links connecting real sensors to a control unit within an aircraft or spacecraft. An important problem which we are planning to focus on during the second year is coupling of optical fiber line to the sensor. Currently this problem is solved using focusing optics and prism couplers. More reliable solutions are planned to be investigated.

Polarization-independent optical wavelength filter for channel dropping applications

DOEpatents

Deri, R.J.; Patterson, F.

1996-05-07

The polarization dependence of optical wavelength filters is eliminated by using waveguide directional couplers. Material birefringence is used to compensate for the waveguide (electromagnetic) birefringence which is the original cause of the polarization dependence. Material birefringence is introduced in a controllable fashion by replacing bulk waveguide layers by finely layered composites, such as multiple quantum wells using III-V semiconductor materials. The filter has use in wavelength-division multiplexed fiber optic communication systems. This filter has broad application for wavelength-tunable receivers in fiber optic communication links, which may be used for telecommunications, optical computer interconnect links, or fiber optic sensor systems. Since multiple-wavelength systems are increasingly being used for all of these applications, the filter is useable whenever a rapidly tunable, wavelength-filtering receiver is required. 14 figs.

Polarization-independent optical wavelength filter for channel dropping applications

DOEpatents

Deri, Robert J.; Patterson, Frank

1996-01-01

The polarization dependence of optical wavelength filters is eliminated by using waveguide directional couplers. Material birefringence is used to compensate for the waveguide (electromagnetic) birefringence which is the original cause of the polarization dependence. Material birefringence is introduced in a controllable fashion by replacing bulk waveguide layers by finely layered composites, such as multiple quantum wells using III-V semiconductor materials. The filter has use in wavelength-division-multiplexed fiber optic communication systems. This filter has broad application for wavelength-tunable receivers in fiber optic communication links, which may be used for telecommunications, optical computer interconnect links, or fiber optic sensor systems. Since multiple-wavelength systems are increasingly being used for all of these applications, the filter is useable whenever a rapidly tunable, wavelength-filtering receiver is required.

Dynamic optical arbitrary waveform shaping based on cascaded optical modulators of single FBG.

PubMed

Chen, Jingyuan; Li, Peili

2015-08-10

A dynamic optical arbitrary waveform generation (O-AWG) with amplitude and phase independently controlled in optical modulators of single fiber Bragg Grating (FBG) has been proposed. This novel scheme consists of several optical modulators. In the optical modulator (O-MOD), a uniform FBG is used to filter spectral component of the input signal. The amplitude is controlled by fiber stretcher (FS) in Mach-Zehnder interference (MZI) structure through interference of two MZI arms. The phase is manipulated via the second FS in the optical modulator. This scheme is investigated by simulation. Consequently, optical pulse trains with different waveforms as well as pulse trains with nonuniform pulse intensity, pulse spacing and pulse width within each period are obtained through FSs adjustment to alter the phase shifts of signal in each O-MOD.

A liquid lens switching-based motionless variable fiber-optic delay line

NASA Astrophysics Data System (ADS)

Khwaja, Tariq Shamim; Reza, Syed Azer; Sheikh, Mumtaz

2018-05-01

We present a Variable Fiber-Optic Delay Line (VFODL) module capable of imparting long variable delays by switching an input optical/RF signal between Single Mode Fiber (SMF) patch cords of different lengths through a pair of Electronically Controlled Tunable Lenses (ECTLs) resulting in a polarization-independent operation. Depending on intended application, the lengths of the SMFs can be chosen accordingly to achieve the desired VFODL operation dynamic range. If so desired, the state of the input signal polarization can be preserved with the use of commercially available polarization-independent ECTLs along with polarization-maintaining SMFs (PM-SMFs), resulting in an output polarization that is identical to the input. An ECTL-based design also improves power consumption and repeatability. The delay switching mechanism is electronically-controlled, involves no bulk moving parts, and can be fully-automated. The VFODL module is compact due to the use of small optical components and SMFs that can be packaged compactly.

Guiding properties and dispersion control of kagome lattice hollow-core photonic crystal fibers.

PubMed

Im, Song-Jin; Husakou, Anton; Herrmann, Joachim

2009-07-20

Dispersion properties, loss and optimum design of kagome lattice hollow-core photonic crystal fibers filled with argon are studied for the purpose of possible applications in ultrafast nonlinear optics. As will be shown numerically and by using an approximate analytical formula these fibers exhibit anomalous dispersion for visible or UV wavelengths both for a 1-cell-core as well for a 3-ring-core which can be controlled by the gas pressure and do not suffer from high loss. It is shown that while the loss is mainly influenced by the strut thickness of the kagome lattice the group velocity dispersion is almost independently controlled by the core size. These results demonstrate that kagome lattice hollow fibers have a promising potential in ultrashort pulse delivering of high-energy pulses and in several interesting applications in ultrafast nonlinear optics.

Medical catheters thermally manipulated by fiber optic bundles

DOEpatents

Chastagner, Philippe

1992-01-01

A maneuverable medical catheter comprising a flexible tube having a functional tip. The catheter is connected to a control source. The functional tip of the catheter carries a plurality of temperature activated elements arranged in parallel and disposed about the functional tip and held in spaced relation at each end. These elements expand when they are heated. A plurality of fiber optic bundles, each bundle having a proximal end attached to the control source and a distal end attached to one of the elements carry light into the elements where the light is absorbed as heat. By varying the optic fiber that is carrying the light and the intensity of the light, the bending of the elements can be controlled and thus the catheter steered. In an alternate embodiment, the catheter carries a medical instrument for gathering a sample of tissue. The instrument may also be deployed and operated by thermal expansion and contraction of its moving parts.

Tuning operating point of extrinsic Fabry-Perot interferometric fiber-optic sensors using microstructured fiber and gas pressure.

PubMed

Tian, Jiajun; Zhang, Qi; Fink, Thomas; Li, Hong; Peng, Wei; Han, Ming

2012-11-15

Intensity-based demodulation of extrinsic Fabry-Perot interferometric (EFPI) fiber-optic sensors requires the light wavelength to be on the quadrature point of the interferometric fringes for maximum sensitivity. In this Letter, we propose a novel and remote operating-point tuning method for EFPI fiber-optic sensors using microstructured fibers (MFs) and gas pressure. We demonstrated the method using a diaphragm-based EFPI sensor with a microstructured lead-in fiber. The holes in the MF were used as gas channels to remotely control the gas pressure inside the Fabry-Perot cavity. Because of the deformation of the diaphragm with gas pressure, the cavity length and consequently the operating point can be remotely tuned for maximum sensitivity. The proposed operating-point tuning method has the advantage of reduced complexity and cost compared to previously reported methods.

Q-plates as higher order polarization controllers for orbital angular momentum modes of fiber.

PubMed

Gregg, P; Mirhosseini, M; Rubano, A; Marrucci, L; Karimi, E; Boyd, R W; Ramachandran, S

2015-04-15

We demonstrate that a |q|=1/2 plate, in conjunction with appropriate polarization optics, can selectively and switchably excite all linear combinations of the first radial mode order |l|=1 orbital angular momentum (OAM) fiber modes. This enables full mapping of free-space polarization states onto fiber vector modes, including the radially (TM) and azimuthally polarized (TE) modes. The setup requires few optical components and can yield mode purities as high as ∼30  dB. Additionally, just as a conventional fiber polarization controller creates arbitrary elliptical polarization states to counteract fiber birefringence and yield desired polarizations at the output of a single-mode fiber, q-plates disentangle degenerate state mixing effects between fiber OAM states to yield pure states, even after long-length fiber propagation. We thus demonstrate the ability to switch dynamically, potentially at ∼GHz rates, between OAM modes, or create desired linear combinations of them. We envision applications in fiber-based lasers employing vector or OAM mode outputs, as well as communications networking schemes exploiting spatial modes for higher dimensional encoding.

Using passive fiber-optic distributed temperature sensing to estimate soil water content at a discontinuous permafrost site

NASA Astrophysics Data System (ADS)

Wagner, A. M.; Lindsey, N.; Ajo Franklin, J. B.; Gelvin, A.; Saari, S.; Ekblaw, I.; Ulrich, C.; Dou, S.; James, S. R.; Martin, E. R.; Freifeld, B. M.; Bjella, K.; Daley, T. M.

2016-12-01

We present preliminary results from an experimental study targeting the use of passive fiber-optic distributed temperature sensing (DTS) in a variety of geometries to estimate moisture content evolution in a dynamic permafrost system. A 4 km continuous 2D array of multi-component fiber optic cable (6 SM/6 MM) was buried at the Fairbanks Permafrost Experiment Station to investigate the possibility of using fiber optic distributed sensing as an early detection system for permafrost thaw. A heating experiment using 120 60 Watt heaters was conducted in a 140 m2 area to artificially thaw the topmost section of permafrost. The soils at the site are primarily silt but some disturbed areas include backfilled gravel to depths of approximately 1.0 m. Where permafrost exists, the depth to permafrost ranges from 1.5 to approximately 5 m. The experiment was also used to spatially estimate soil water content distribution throughout the fiber optic array. The horizontal fiber optic cable was buried at depths between 10 and 20 cm. Soil temperatures were monitored with a DTS system at 25 cm increments along the length of the fiber. At five locations, soil water content time-domain reflectometer (TDR) probes were also installed at two depths, in line with the fiber optic cable and 15 to 25 cm below the cable. The moisture content along the fiber optic array was estimated using diurnal effects from the dual depth temperature measurements. In addition to the horizontally installed fiber optic cable, vertical lines of fiber optic cable were also installed inside and outside the heater plot to a depth of 10 m in small diameter (2 cm) boreholes. These arrays were installed in conjunction with thermistor strings and are used to monitor the thawing process and to cross correlate with soil temperatures at the depth of the TDR probes. Results will be presented from the initiation of the artificial thawing through subsequent freeze-up. A comparison of the DTS measured temperatures and thermistors in vertically installed PVC pipes will also be shown. Initial results from a thermal model of the artificial heating experiment and the model's correlation to the actual soil temperature measurements will also be presented. These results show the possibility of using fiber optic cable to measure moisture contents along a longer array with only limited control points.

Shape Sensing Using a Multi-Core Optical Fiber Having an Arbitrary Initial Shape in the Presence of Extrinsic Forces

NASA Technical Reports Server (NTRS)

Rogge, Matthew D. (Inventor); Moore, Jason P. (Inventor)

2014-01-01

Shape of a multi-core optical fiber is determined by positioning the fiber in an arbitrary initial shape and measuring strain over the fiber's length using strain sensors. A three-coordinate p-vector is defined for each core as a function of the distance of the corresponding cores from a center point of the fiber and a bending angle of the cores. The method includes calculating, via a controller, an applied strain value of the fiber using the p-vector and the measured strain for each core, and calculating strain due to bending as a function of the measured and the applied strain values. Additionally, an apparent local curvature vector is defined for each core as a function of the calculated strain due to bending. Curvature and bend direction are calculated using the apparent local curvature vector, and fiber shape is determined via the controller using the calculated curvature and bend direction.

Scheme for generating the singlet state of three atoms trapped in distant cavities coupled by optical fibers

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

Wang, Dong-Yang; Wen, Jing-Ji; Bai, Cheng-Hua

2015-09-15

An effective scheme is proposed to generate the singlet state with three four-level atoms trapped in three distant cavities connected with each other by three optical fibers, respectively. After a series of appropriate atom–cavity interactions, which can be arbitrarily controlled via the selective pairing of Raman transitions and corresponding optical switches, a three-atom singlet state can be successfully generated. The influence of atomic spontaneous decay, photon leakage of cavities and optical fibers on the fidelity of the state is numerically simulated showing that the three-atom singlet state can be generated with high fidelity by choosing the experimental parameters appropriately.

Fiber optic, Fabry-Perot high temperature sensor

NASA Technical Reports Server (NTRS)

James, K.; Quick, B.

1984-01-01

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

Innovative architecture of switching device for expanding the applications in fiber to the home (FTTH)

NASA Astrophysics Data System (ADS)

Mahmoud, Mohamed; Fayed, Heba A.; Aly, Moustafa H.; Aboul Seoud, A. K.

2011-08-01

A new device, optical cross add drop multiplexer (OXADM), is proposed and analyzed. It uses the combination concept of optical add drop multiplexer (OADM) and optical cross connect (OXC). It enables a wavelength switch while implementing add and drop functions simultaneously. So, it expands the applications in fiber to the home (FTTH) and optical core networks. A very high isolation crosstalk level (~ 60 dB) is achieved. Also, a bidirectional OXADM and N×N OXADM are proposed. Finally, a multistage OXADM is presented making some sort of wavelength buffering. To make these devices operate more efficient, tunable fiber Bragg gratings (TFBGs) switches are used to control the operation mechanism.

Wireless optical transceiver design, link analisys and alignment control for mobile communication

NASA Astrophysics Data System (ADS)

Zhou, Dayong

Pointing, acquisition and tracking of a free-space optical node in a mobile network experiencing misalignment due to adverse factors including vibration, motion and atmospheric turbulence requires a different approach than traditional free-space optical transceivers. A recent fiber-bundle approach for beam steering at the transmitter was investigated to provide continuous beam coverage at the receiver without the application of mechanical devices. Utilizing multiple fibers-lenses sets at the receiver was also proposed to enhance the tolerance of optical link misalignment. In this work, both laboratory experiments and software simulation were implemented to evaluate the optical link performance for different fiber-bundle-based transceiver setups as the link parameters were varied. The performance was evaluated in terms of the coverage area at the receiver, which is a measure of misalignment tolerance and is dependent not only on wavelength but on other key parameters such as link length, transmitted power, the pattern of transmitters, beam divergence, and the receiver construction. The results showed that fiber-bindle-based transceivers reveal significant potential to maximize the up time of the link, and the results also provide guidance on the further development of the overall system. To incorporate the proposed transceiver designs, an alignment control system was developed and evaluated as well. The laboratory results show that the optical control system successfully recovered and maintained the link while the receiver was in motion and the signal coverage at the target area was enhanced significantly.

On a Road to "Soft" Optical MEMS

NASA Astrophysics Data System (ADS)

Yang, Shu; Mach, Peter; Krupenkin, Tom

2003-03-01

A phenomenon of electrowetting has been applied to the actuation of micro-optical devices. The devices use small droplets of transparent conductive liquids to manipulate light in a useful way. The form and position of these droplets is controlled by the applied voltage. Both fiber based and open space optical devices are demonstrated. As an example of an open space optical device, a tunable liquid microlens capable of adjusting its focal length and lateral position is discussed. The microlens consists of a droplet of a transparent conductive liquid placed on a dielectric substrate with underlying electrodes. By varying the voltage applied to the structure, both the position and curvature of microlens can be reversibly changed. Similarly, electrowetting actuation of fluids in micro channels is employed to provide dynamic and reversible tuning of the optical fiber structures. When combined with in-fiber gratings or etched fibers this approach yields tunable broadband and narrowband filters with a large dynamic range. Both the surface and bulk properties of the materials are found important to control the device performance. Fundamental problems, such as stick-slip behavior and contact angle hysteresis associated with the surface roughness and surface contamination, are studied to optimize the choice of dielectric materials and their coatings. Some of the possible ways to control these phenomena are outlined. Several potential applications of the proposed approach are also discussed.

Glass-ceramic optical fiber containing Ba2TiSi2O8 nanocrystals for frequency conversion of lasers

NASA Astrophysics Data System (ADS)

Fang, Zaijin; Xiao, Xusheng; Wang, Xin; Ma, Zhijun; Lewis, Elfed; Farrell, Gerald; Wang, Pengfei; Ren, Jing; Guo, Haitao; Qiu, Jianrong

2017-03-01

A glass-ceramic optical fiber containing Ba2TiSi2O8 nanocrystals fabricated using a novel combination of the melt-in-tube method and successive heat treatment is reported for the first time. For the melt-in-tube method, fibers act as a precursor at the drawing temperature for which the cladding glass is softened while the core glass is melted. It is demonstrated experimentally that following heat treatment, Ba2TiSi2O8 nanocrystals with diameters below 10 nm are evenly distributed throughout the fiber core. Comparing to the conventional rod-in-tube method, the melt-in-tube method is superior in terms of controllability of crystallization to allow for the fabrication of low loss glass-ceramic fibers. When irradiated using a 1030 nm femtosecond laser, an enhanced green emission at a wavelength of 515 nm is observed in the glass-ceramic fiber, which demonstrates second harmonic generation of a laser action in the fabricated glass-ceramic fibers. Therefore, this new glass-ceramic fiber not only provides a highly promising development for frequency conversion of lasers in all optical fiber based networks, but the melt-in-tube fabrication method also offers excellent opportunities for fabricating a wide range of novel glass-ceramic optical fibers for multiple future applications including fiber telecommunications and lasers.

Glass-ceramic optical fiber containing Ba2TiSi2O8 nanocrystals for frequency conversion of lasers

PubMed Central

Fang, Zaijin; Xiao, Xusheng; Wang, Xin; Ma, Zhijun; Lewis, Elfed; Farrell, Gerald; Wang, Pengfei; Ren, Jing; Guo, Haitao; Qiu, Jianrong

2017-01-01

A glass-ceramic optical fiber containing Ba2TiSi2O8 nanocrystals fabricated using a novel combination of the melt-in-tube method and successive heat treatment is reported for the first time. For the melt-in-tube method, fibers act as a precursor at the drawing temperature for which the cladding glass is softened while the core glass is melted. It is demonstrated experimentally that following heat treatment, Ba2TiSi2O8 nanocrystals with diameters below 10 nm are evenly distributed throughout the fiber core. Comparing to the conventional rod-in-tube method, the melt-in-tube method is superior in terms of controllability of crystallization to allow for the fabrication of low loss glass-ceramic fibers. When irradiated using a 1030 nm femtosecond laser, an enhanced green emission at a wavelength of 515 nm is observed in the glass-ceramic fiber, which demonstrates second harmonic generation of a laser action in the fabricated glass-ceramic fibers. Therefore, this new glass-ceramic fiber not only provides a highly promising development for frequency conversion of lasers in all optical fiber based networks, but the melt-in-tube fabrication method also offers excellent opportunities for fabricating a wide range of novel glass-ceramic optical fibers for multiple future applications including fiber telecommunications and lasers. PMID:28358045

Glass-ceramic optical fiber containing Ba2TiSi2O8 nanocrystals for frequency conversion of lasers.

PubMed

Fang, Zaijin; Xiao, Xusheng; Wang, Xin; Ma, Zhijun; Lewis, Elfed; Farrell, Gerald; Wang, Pengfei; Ren, Jing; Guo, Haitao; Qiu, Jianrong

2017-03-30

A glass-ceramic optical fiber containing Ba 2 TiSi 2 O 8 nanocrystals fabricated using a novel combination of the melt-in-tube method and successive heat treatment is reported for the first time. For the melt-in-tube method, fibers act as a precursor at the drawing temperature for which the cladding glass is softened while the core glass is melted. It is demonstrated experimentally that following heat treatment, Ba 2 TiSi 2 O 8 nanocrystals with diameters below 10 nm are evenly distributed throughout the fiber core. Comparing to the conventional rod-in-tube method, the melt-in-tube method is superior in terms of controllability of crystallization to allow for the fabrication of low loss glass-ceramic fibers. When irradiated using a 1030 nm femtosecond laser, an enhanced green emission at a wavelength of 515 nm is observed in the glass-ceramic fiber, which demonstrates second harmonic generation of a laser action in the fabricated glass-ceramic fibers. Therefore, this new glass-ceramic fiber not only provides a highly promising development for frequency conversion of lasers in all optical fiber based networks, but the melt-in-tube fabrication method also offers excellent opportunities for fabricating a wide range of novel glass-ceramic optical fibers for multiple future applications including fiber telecommunications and lasers.

A Feasibility Study on Monitoring Residual Sugar and Alcohol Strength in Kiwi Wine Fermentation Using a Fiber-Optic FT-NIR Spectrometry and PLS Regression.

PubMed

Wang, Bingqian; Peng, Bangzhu

2017-02-01

This work aims to investigate the potential of fiber-optic Fourier transform-near-infrared (FT-NIR) spectrometry associated with chemometric analysis, which will be applied to monitor time-related changes in residual sugar and alcohol strength during kiwi wine fermentation. NIR calibration models for residual sugar and alcohol strength during kiwi wine fermentation were established on the FT-NIR spectra of 98 samples scanned in a fiber-optic FT-NIR spectrometer, and partial least squares regression method. The results showed that R 2 and root mean square error of cross-validation could achieve 0.982 and 3.81 g/L for residual sugar, and 0.984 and 0.34% for alcohol strength, respectively. Furthermore, crucial process information on kiwi must and wine fermentations provided by fiber-optic FT-NIR spectrometry was found to agree with those obtained from traditional chemical methods, and therefore this fiber-optic FT-NIR spectrometry can be applied as an effective and suitable alternative for analyses and monitoring of those processes. The overall results suggested that fiber-optic FT-NIR spectrometry is a promising tool for monitoring and controlling the kiwi wine fermentation process. © 2017 Institute of Food Technologists®.

Morphological appearances and photo-controllable coloration of dye-doped cholesteric liquid crystal/polymer coaxial microfibers fabricated by coaxial electrospinning technique.

PubMed

Lin, Jia-De; Chen, Che-Pei; Chen, Lin-Jer; Chuang, Yu-Chou; Huang, Shuan-Yu; Lee, Chia-Rong

2016-02-08

This study systematically investigates the morphological appearance of azo-chiral dye-doped cholesteric liquid crystal (DDCLC)/polymer coaxial microfibers obtained through the coaxial electrospinning technique and examines, for the first time, their photocontrollable reflection characteristics. Experimental results show that the quasi-continuous electrospun microfibers can be successfully fabricated at a high polymer concentration of 17.5 wt% and an optimum ratio of 2 for the feeding rates of sheath to core materials at 25 °C and a high humidity of 50% ± 2% in the spinning chamber. Furthermore, the optical controllability of the reflective features for the electrospun fibers is studied in detail by changing the concentration of the azo-chiral dopant in the core material, the UV irradiation intensity, and the core diameter of the fibers. Relevant mechanisms are addressed to explain the optical-control behaviors of the DDCLC coaxial fibers. Considering the results, optically controllable DDCLC coaxial microfibers present potential applications in UV microsensors and wearable smart textiles or swabs.

No moving parts safe & arm apparatus and method with monitoring and built-in-test for optical firing of explosive systems

DOEpatents

Hendrix, J.L.

1995-04-11

A laser initiated ordnance controller apparatus which provides a safe and arm scheme with no moving parts. The safe & arm apparatus provides isolation of firing energy to explosive devices using a combination of polarization isolation and control through acousto-optical deviation of laser energy pulses. The apparatus provides constant monitoring of the systems status and performs 100% built-in-test at any time prior to ordnance ignition without the risk of premature ignition or detonation. The apparatus has a computer controller, a solid state laser, an acousto-optic deflector and RF drive circuitry, built-in-test optics and electronics, and system monitoring capabilities. The optical system is completed from the laser beam power source to the pyrotechnic ordnance through fiber optic cabling, optical splitters and optical connectors. During operation of the apparatus, a command is provided by the computer controller and, simultaneous with laser flashlamp fire, the safe & arm device is opened for approximately 200 microseconds which allows the laser pulse to transmit through the device. The arm signal also energizes the laser power supply and activates the acousto-optical deflector. When the correct fire format command is received, the acousto-optic deflector moves to the selected event channel, and the channel is verified to ensure the system is pointing to the correct position. Laser energy is transmitted through the fiber where an ignitor or detonator designed to be sensitive to optical pulses is fired at the end of the fiber channel. Simultaneous event channels may also be utilized by optically splitting a single event channel. The built-in-test may be performed anytime prior to ordnance ignition. 6 figures.

No moving parts safe & arm apparatus and method with monitoring and built-in-test for optical firing of explosive systems

DOEpatents

Hendrix, James L.

1995-01-01

A laser initiated ordnance controller apparatus which provides a safe and m scheme with no moving parts. The safe & arm apparatus provides isolation of firing energy to explosive devices using a combination of polarization isolation and control through acousto-optical deviation of laser energy pulses. The apparatus provides constant monitoring of the systems status and performs 100% built-in-test at any time prior to ordnance ignition without the risk of premature ignition or detonation. The apparatus has a computer controller, a solid state laser, an acousto-optic deflector and RF drive circuitry, built-in-test optics and electronics, and system monitoring capabilities. The optical system is completed from the laser beam power source to the pyrotechnic ordnance through fiber optic cabling, optical splitters and optical connectors. During operation of the apparatus, a command is provided by the computer controller and, simultaneous with laser flashlamp fire, the safe & arm device is opened for approximately 200 microseconds which allows the laser pulse to transmit through the device. The arm signal also energizes the laser power supply and activates the acousto-optical deflector. When the correct fire format command is received, the acousto-optic deflector moves to the selected event channel, and the channel is verified to ensure the system is pointing to the correct position. Laser energy is transmitted through the fiber where an ignitor or detonator designed to be sensitive to optical pulses is fired at the end of the fiber channel. Simultaneous event channels may also be utilized by optically splitting a single event channel. The built-in-test may be performed anytime prior to ordnance ignition.

Statistical characteristics of excess fiber length in loose tubes of optical cable

NASA Astrophysics Data System (ADS)

Andreev, Vladimir A.; Gavryushin, Sergey A.; Popov, Boris V.; Popov, Victor B.; Vazhdaev, Michael A.

2017-04-01

This paper presents an analysis of the data measurements of excess fiber length in the loose tubes of optical cable during the post-process quality control of ready-made products. At determining estimates of numerical characteristics of excess fiber length method of results processing of direct multiple equally accurate measurements has been used. The results of experimental research of the excess length value at the manufacturing technology of loose tube remains constant.

Meeting Future C3I (Command-Control-Communications-Intelligence) Needs with Fiber Optics,

DTIC Science & Technology

1985-05-01

Frequency dependence of the sensitivity of fibers with hard coatings is relatively small. Nylon gives the weakest dependence, while the soft UV -cured...elastomer gives the strongest. Maximum sensitivity is obtained with Teflon TFE, while the minimum is achieved with the soft UV coating. With the latter...fiber-optics systems: the LED (Light Emitting Diode) and ILD (Injection Laser Diode). These devices emit light when an electric current is applied. The

Coagulation measurement from whole blood using vibrating optical fiber in a disposable cartridge.

PubMed

Yaraş, Yusuf Samet; Gündüz, Ali Bars; Sağlam, Gökhan; Ölçer, Selim; Civitçi, Fehmi; Baris, İbrahim; Yaralioğlu, Göksenin; Urey, Hakan

2017-11-01

In clinics, blood coagulation time measurements are performed using mechanical measurements with blood plasma. Such measurements are challenging to do in a lab-on-a-chip (LoC) system using a small volume of whole blood. Existing LoC systems use indirect measurement principles employing optical or electrochemical methods. We developed an LoC system using mechanical measurements with a small volume of whole blood without requiring sample preparation. The measurement is performed in a microfluidic channel where two fibers are placed inline with a small gap in between. The first fiber operates near its mechanical resonance using remote magnetic actuation and immersed in the sample. The second fiber is a pick-up fiber acting as an optical sensor. The microfluidic channel is engineered innovatively such that the blood does not block the gap between the vibrating fiber and the pick-up fiber, resulting in high signal-to-noise ratio optical output. The control plasma test results matched well with the plasma manufacturer's datasheet. Activated-partial-thromboplastin-time tests were successfully performed also with human whole blood samples, and the method is proven to be effective. Simplicity of the cartridge design and cost of readily available materials enable a low-cost point-of-care device for blood coagulation measurements. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Micro guidance and control synthesis: New components, architectures, and capabilities

NASA Technical Reports Server (NTRS)

Mettler, Edward; Hadaegh, Fred Y.

1993-01-01

New GN&C (guidance, navigation and control) system capabilities are shown to arise from component innovations that involve the synergistic use of microminiature sensors and actuators, microelectronics, and fiber optics. Micro-GN&C system and component concepts are defined that include micro-actuated adaptive optics, micromachined inertial sensors, fiber-optic data nets and light-power transmission, and VLSI microcomputers. The thesis is advanced that these micro-miniaturization products are capable of having a revolutionary impact on space missions and systems, and that GN&C is the pathfinder micro-technology application that can bring that about.

Development of an optical fiber SERS microprobe for minimally invasive sensing applications

NASA Astrophysics Data System (ADS)

Mamun, Md Abdullah Al; Juodkazis, Saulius; Mahadevan-Jansen, Anita; Stoddart, Paul R.

2018-02-01

Numerous potential biomedical sensing applications of surface-enhanced Raman scattering (SERS) have been reported, but its practical use has been limited by the lack of a robust sensing platform. Optical fiber SERS probes show great promise, but are limited by the prominent silica Raman background, which requires the use of bulky optics for filtering the signal collection and excitation delivery paths. In the present study, a SERS microprobe has been designed and developed to eliminate the bottlenecks outlined above. For efficient excitation and delivery of the SERS signal, both hollow core photonic crystal fiber and double clad fiber have been investigated. While the hollow core fiber was still found to have excessive silica background, the double clad fiber allows efficient signal collection via the multi-mode inner cladding. A micro filtering mechanism has been designed, which can be integrated into the tip of the optical fiber SERS probe, providing filtering to suppress silica Raman background and thus avoiding the need for bulky optics. The design also assists in the efficient collection of SERS signal from the sample by rejecting Rayleigh scattered light from the sample. Optical fiber cleaving using ultra-short laser pulses was tested for improved control of the fiber tip geometry. With this miniaturized and integrated filtering mechanism, it is expected that the developed probe will promote the use of SERS for minimally invasive biomedical monitoring and sensing applications in future. The probe could potentially be placed inside a small gauge hypodermic needle and would be compatible with handheld portable spectrometers.

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

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.

Infrared fiber optic sensor for measurements of nonuniform temperature distributions

NASA Astrophysics Data System (ADS)

Belotserkovsky, Edward; Drizlikh, S.; Zur, Albert; Bar-Or, O.; Katzir, Abraham

1992-04-01

Infrared (IR) fiber optic radiometry of thermal surfaces offers several advantages over refractive optics radiometry. It does not need a direct line of sight to the measured thermal surface and combines high capability of monitoring small areas with high efficiency. These advantages of IR fibers are important in the control of nonuniform temperature distributions, in which the temperature of closely situated points differs considerably and a high spatial resolution is necessary. The theoretical and experimental transforming functions of the sensor during scanning of an area with a nonuniform temperature distribution were obtained and their dependence on the spacial location of the fiber and type of temperature distribution were analyzed. Parameters such as accuracy and precision were determined. The results suggest that IR fiber radiometric thermometry may be useful in medical applications such as laser surgery, hyperthermia, and hypothermia.

innoFSPEC: fiber optical spectroscopy and sensing

NASA Astrophysics Data System (ADS)

Roth, Martin M.; Löhmannsröben, Hans-Gerd; Kelz, Andreas; Kumke, Michael

2008-07-01

innoFSPEC Potsdam is presently being established as in interdisciplinary innovation center for fiber-optical spectroscopy and sensing, hosted by Astrophysikalisches Institut Potsdam and the Physical Chemistry group of Potsdam University, Germany. The center focuses on fundamental research in the two fields of fiber-coupled multi-channel spectroscopy and optical fiber-based sensing. Thanks to its interdisciplinary approach, the complementary methodologies of astrophysics on the one hand, and physical chemistry on the other hand, are expected to spawn synergies that otherwise would not normally become available in more standard research programmes. innoFSPEC targets future innovations for next generation astrophysical instrumentation, environmental analysis, manufacturing control and process monitoring, medical diagnostics, non-invasive imaging spectroscopy, biopsy, genomics/proteomics, high-throughput screening, and related applications.

Fiber optic TV direct

NASA Technical Reports Server (NTRS)

Kassak, John E.

1991-01-01

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

The development of a fiber optics communication network for controlling a Multidegree-Of-Freedom Serpentine Truss

NASA Astrophysics Data System (ADS)

Andrawis, Alfred S.

1994-10-01

The problem addressed by this report is the large size and heavy weight of the cable bundle, used for controlling a Multidegree-Of-Freedom Serpentine Truss Manipulator arm, which imposes limitations on the manipulator arm maneuverability. This report covers a design of an optical fiber network to replace the existing copper wire network of the Serpentine Truss Manipulator. This report proposes a fiber network design which significantly reduces the bundle size into two phases. The first phase does not require any modifications for the manipulator architecture, while the other requires major modifications. Design philosophy, hardware details and schematic diagrams are presented.

The development of a fiber optics communication network for controlling a Multidegree-Of-Freedom Serpentine Truss

NASA Technical Reports Server (NTRS)

Andrawis, Alfred S.

1994-01-01

The problem addressed by this report is the large size and heavy weight of the cable bundle, used for controlling a Multidegree-Of-Freedom Serpentine Truss Manipulator arm, which imposes limitations on the manipulator arm maneuverability. This report covers a design of an optical fiber network to replace the existing copper wire network of the Serpentine Truss Manipulator. This report proposes a fiber network design which significantly reduces the bundle size into two phases. The first phase does not require any modifications for the manipulator architecture, while the other requires major modifications. Design philosophy, hardware details and schematic diagrams are presented.

Polarization switch of four-wave mixing in a lawtunable fiber optical parametric oscillator.

PubMed

Yang, Kangwen; Ye, Pengbo; Zheng, Shikai; Jiang, Jieshi; Huang, Kun; Hao, Qiang; Zeng, Heping

2018-02-05

We reported the simultaneous generation and selective manipulation of scalar and cross-phase modulation instabilities in a fiber optical parametric oscillator. Numerical and experimental results show independent control of parametric gain by changing the input pump polarization state. The resonant cavity enables power enhancement of 45 dB for the spontaneous sidebands, generating laser pulses tunable from 783 to 791 nm and 896 to 1005 nm due to the combination of four-wave mixing, cascaded Raman scattering and other nonlinear effects. This gain controlled, wavelength tunable, fiber-based laser source may find applications in the fields of nonlinear biomedical imaging and stimulated Raman spectroscopy.

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.

International Instrumentation Symposium, 34th, Albuquerque, NM, May 2-6, 1988, Proceedings

NASA Astrophysics Data System (ADS)

Various papers on aerospace instrumentation are presented. The general topics addressed include: blast and shock, wind tunnel instrumentations and controls, digital/optical sensors, software design/development, special test facilities, fiber optic techniques, electro/fiber optical measurement systems, measurement uncertainty, real time systems, pressure. Also discussed are: flight test and avionics instrumentation, data acquisition techniques, computer applications, thermal force and displacement, science and government, modeling techniques, reentry vehicle testing, strain and pressure.

Fabrication and characterization of a nanometer-sized optical fiber electrode based on selective chemical etching for scanning electrochemical/optical microscopy.

PubMed

Maruyama, Kenichi; Ohkawa, Hiroyuki; Ogawa, Sho; Ueda, Akio; Niwa, Osamu; Suzuki, Koji

2006-03-15

We have already reported a method for fabricating ultramicroelectrodes (Suzuki, K. JP Patent, 2004-45394, 2004). This method is based on the selective chemical etching of optical fibers. In this work, we undertake a detailed investigation involving a combination of etched optical fibers with various types of tapered tip (protruding-shape, double- (or pencil-) shape and triple-tapered electrode) and insulation with electrophoretic paint. Our goal is to establish a method for fabricating nanometer-sized optical fiber electrodes with high reproducibility. As a result, we realized pencil-shaped and triple-tapered electrodes that had radii in the nanometer range with high reproducibility. These nanometer-sized electrodes showed well-defined sigmoidal curves and stable diffusion-limited responses with cyclic voltammetry. The pencil-shaped optical fiber, which has a conical tip with a cone angle of 20 degrees , was effective for controlling the electrode radius. The pencil-shaped electrodes had higher reproducibility and smaller electrode radii (r(app) < 1.0 nm) than those of other etched optical fiber electrodes. By using a pencil-shaped electrode with a 105-nm radius as a probe, we obtained simultaneous electrochemical and optical images of an implantable interdigitated array electrode. We achieved nanometer-scale resolution with a combination of scanning electrochemical microscopy SECM and optical microscopy. The resolution of the electrochemical and optical images indicated sizes of 300 and 930 nm, respectively. The neurites of living PC12 cells were also successfully imaged on a 1.6-microm scale by using the negative feedback mode of an SECM.

Power system applications of fiber optic sensors

NASA Technical Reports Server (NTRS)

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

1986-01-01

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

Method and apparatus for determining the physical properties of materials using dynamic light scattering techniques

NASA Technical Reports Server (NTRS)

Dhadwal, Harbans S. (Inventor)

1992-01-01

A system for determining the physical properties of materials through the use of dynamic light scattering is disclosed. The system includes a probe, a laser source for directing a laser beam into the probe, and a photodetector for converting scattered light detected by the probe into electrical signals. The probe includes at least one optical fiber connected to the laser source and a second optical fiber connected to the photodetector. Each of the fibers may adjoin a gradient index microlens which is capable of providing a collimated laser beam into a scattering medium. The position of the second optical fiber with respect to the optical axis of the probe determines whether homodyne or self-beating detection is provided. Self-beating detection may be provided without a gradient index microlens. This allows a very small probe to be constructed which is insertable through a hypodermic needle or the like into a droplet extending from such a needle. A method of detecting scattered light through the use of a collimated, Gaussian laser beam is also provided. A method for controlling the waist and divergence of the optical field emanating from the free end of an optical fiber is also provided.

Fiber optic sensor system for detecting movement or position of a rotating wheel bearing

DOEpatents

Veeser, Lynn R.; Rodriguez, Patrick J.; Forman, Peter R.; Monahan, Russell E.; Adler, Jonathan M.

1997-01-01

An improved fiber optic sensor system and integrated sensor bearing assembly for detecting movement or position of a rotating wheel bearing having a multi-pole tone ring which produces an alternating magnetic field indicative of movement and position of the rotating member. A magneto-optical material, such as a bismuth garnet iron (B.I.G.) crystal, having discrete magnetic domains is positioned in the vicinity of the tone ring so that the domains align themselves to the magnetic field generated by the tone ring. A single fiber optic cable, preferably single mode fiber, carries light generated by a source of light to the B.I.G. crystal. The light passes through the B.I.G. crystal and is refracted at domain boundaries in the crystal. The intensity of the refracted light is indicative of the amount of alignment of the domains and therefore the strength of the magnetic field. The refracted light is carried by the fiber optic cable to an optic receiver where the intensity is measured and an electrical signal is generated and sent to a controller indicating the frequency of the changes in light intensity and therefore the rotational speed of the rotating wheel bearing.

Optically controlled phased-array antenna technology for space communication systems

NASA Technical Reports Server (NTRS)

Kunath, Richard R.; Bhasin, Kul B.

1988-01-01

Using MMICs in phased-array applications above 20 GHz requires complex RF and control signal distribution systems. Conventional waveguide, coaxial cable, and microstrip methods are undesirable due to their high weight, high loss, limited mechanical flexibility and large volume. An attractive alternative to these transmission media, for RF and control signal distribution in MMIC phased-array antennas, is optical fiber. Presented are potential system architectures and their associated characteristics. The status of high frequency opto-electronic components needed to realize the potential system architectures is also discussed. It is concluded that an optical fiber network will reduce weight and complexity, and increase reliability and performance, but may require higher power.

Optical bandwidth in coupling: the multicore photonic switch.

PubMed

Attard, Alfred E

2003-05-20

In the present study, the bandwidth of a photonic switch described previously [Appl. Opt. 37,2296 (1998); 38, 3239 (1999)] is evaluated. First the optical bandwidth is evaluated for coupling between two fiber-core waveguides, in which the cores are embedded within the same cladding. Then the coupling bandwidth is determined for a fiber-core-to-slab-core waveguide, in which the cores are embedded within the same cladding. These bandwidths are then compared and contrasted with the bandwidths of the photonic switch, which consists of two fiber cores and a control waveguide. Two configurations of the photonic switch are considered: one in which the control waveguide is a fiber core and one in which the control waveguide is a slab core. For the photonic switch, the bandwidth characteristics are more complicated than for the coupled pairs, and these characteristics are discussed in detail.

Fiber sensors for control and health monitoring system for mining machinery

NASA Astrophysics Data System (ADS)

Claus, Richard O.; Gunther, Michael F.; Greene, Jonathan A.; Tran, Tuan A.; Murphy, Kent A.

1994-05-01

This paper describes initial results of a fiber optic-based sensor during on-site testing performed by FEORC and Fiber and Sensor Technologies at Ingersol-Rand. Advantages of the fiber optic sensor are a demonstrated enhanced survivability, higher sensitivity, smaller size, electromagnetic interference immunity, and reduced risk of explosion. The conventional wire strain gages typically survive only a few minutes attached to the drill steel and drive chain, while the fiber sensors described here have survived over 400 hours and are currently still functioning properly. The tests described include the demonstration of strain energy measurements on the drive chain and drill steel, and displacement measurements of the piston within the drifter. All of the sensors tested can be used as both a laboratory evaluation and testing tools, as well as being an integral part of a proposed control and health monitoring system.

Developments in photonic and mm-wave component technology for fiber radio

NASA Astrophysics Data System (ADS)

Iezekiel, Stavros

2013-01-01

A review of photonic component technology for fiber radio applications at 60 GHz will be given. We will focus on two architectures: (i) baseband-over-fiber and (ii) RF-over-fiber. In the first approach, up-conversion to 60 GHz is performed at the picocell base stations, with data being transported over fiber, while in the second both the data and rum­ wave carrier are transported over fiber. For the baseband-over-fiber scheme, we examine techniques to improve the modulation efficiency of directly­ modulated fiber links. These are based on traveling-wave structures applied to series cascades of lasers. This approach combines the improvement in differential quantum efficiency with the ability to tailor impedance matching as required. In addition, we report on various base station transceiver architectures based on optically-controlled :tvfMIC self­ oscillating mixers, and their application to 60 GHz fiber radio. This approach allows low cost optoelectronic transceivers to be used for the baseband fiber link, whilst minimizing the impact of dispersion. For the RF-over-fiber scheme, we report on schemes for optical generation of 100 GHz. These use modulation of a Mach-Zehnder modulator at Vπ bias in cascade with a Mach-Zehnder driven by 1.25 Gb/s data. One of the issues in RF-over-fiber is dispersion, while reduced modulation efficiency due to the presence of the optical carrier is also problematic. We examine the use of silicon nitride micro-ring resonators for the production of optical single sideband modulation in order to combat dispersion, and for the reduction of optical carrier power in order to improve link modulation efficiency.

All fiber optics circular-state swept source polarization-sensitive optical coherence tomography.

PubMed

Lin, Hermann; Kao, Meng-Chun; Lai, Chih-Ming; Huang, Jyun-Cin; Kuo, Wen-Chuan

2014-02-01

A swept source (SS)-based circular-state (CS) polarization-sensitive optical coherence tomography (PS-OCT) constructed entirely with polarization-maintaining fiber optics components is proposed with the experimental verification. By means of the proposed calibration scheme, bulk quarter-wave plates can be replaced by fiber optics polarization controllers to, therefore, realize an all-fiber optics CS SSPS-OCT. We also present a numerical dispersion compensation method, which can not only enhance the axial resolution, but also improve the signal-to-noise ratio of the images. We demonstrate that this compact and portable CS SSPS-OCT system with an accuracy comparable to bulk optics systems requires less stringent lens alignment and can possibly serve as a technology to realize PS-OCT instrument for clinical applications (e.g., endoscopy). The largest deviations in the phase retardation (PR) and fast-axis (FA) angle due to sample probe in the linear scanning and a rotation angle smaller than 65 deg were of the same order as those in stationary probe setups. The influence of fiber bending on the measured PR and FA is also investigated. The largest deviations of the PR were 3.5 deg and the measured FA change by ~12 to 21 deg. Finally, in vivo imaging of the human fingertip and nail was successfully demonstrated with a linear scanning probe.

Optical Fiber Illumination System for visual flight simulation

NASA Technical Reports Server (NTRS)

Hollow, R. H.

1981-01-01

An electronically controlled lighting system simulating runway, aircraft carrier, and landing aid lights for flight simulations is described. The various colored lights that would be visible to a pilot by day, at dusk, or at night are duplicated at the distances the lights would normally become visible. Plastic optical fiber illuminators using tungsten halogen lights are distributed behind the model. The tips of the fibers of illuminators simulating runway lights are bevelled in order that they may be seen from long distances and at low angles. Fibers representing taxiway lights are pointed and polished for omni-directional visibility. The electronic intensity controls, which can be operated either manually or remotely, regulate the intensity of the lights to simulate changes in distance. A dichronic mirror, infrared filter system is used to maintain color integrity.

Optical fiber sensors: Accelerating applications in Navy ships

NASA Astrophysics Data System (ADS)

Day, G. W.; Lovely, P. S.; Whitesel, H. K.; Hickernell, R. K.

1994-05-01

The Navy needs new sensors for shipboard machinery monitoring and control, condition-based maintenance, and damage assessment. Optical fiber sensors are strongly preferred because of their immunity to electrical disturbances, as well as potential size, weight, and performance advantages. But despite well over a decade of development and promise, relatively few optical fiber sensors available today can meet the Navy's needs with acceptable performance and cost. This report examines the reasons and recommends strategies to help the Navy achieve its goals. Some of the recommendations confirm approaches that the Navy is already implementing. Optical fiber sensors have very valuable potential advantages, but those that the Navy can use may remain too expensive to be deployed if the Navy uses traditional methods of writing specifications and soliciting development and procurement bids. For this reason, the study focuses on cooperation with industry and promoting commercial off-the-shelf and dual-use technology.

Fast and accurate determination of the detergent efficiency by optical fiber sensors

NASA Astrophysics Data System (ADS)

Patitsa, Maria; Pfeiffer, Helge; Wevers, Martine

2011-06-01

An optical fiber sensor was developed to control the cleaning efficiency of surfactants. Prior to the measurements, the sensing part of the probe is covered with a uniform standardized soil layer (lipid multilayer), and a gold mirror is deposited at the end of the optical fiber. For the lipid multilayer deposition on the fiber, Langmuir-Blodgett technique was used and the progress of deposition was followed online by ultraviolet spectroscopy. The invention provides a miniaturized Surface Plasmon Resonance dip-sensor for automated on-line testing that can replace the cost and time consuming existing methods and develop a breakthrough in detergent testing in combining optical sensing, surface chemistry and automated data acquisition. The sensor is to be used to evaluate detergency of different cleaning products and also indicate how formulation, concentration, lipid nature and temperature affect the cleaning behavior of a surfactant.

Immunoassay procedures for fiber optic sensors

NASA Astrophysics Data System (ADS)

Ligler, Frances S.

1988-04-01

There is an increasing need for the development of an ultrasensitive immunoassay for use with fiber optic sensors. These detection systems can be used for such applications as disease diagnosis, detection of chemical and biological warfare agents or drugs of abuse, pollution control, therapeutic monitoring, and explosive detection. This specific program is designed to produce generic chemistries for use with existing fiber optic-based sensors to detect pathogens of particular threat to Army personnel as determined by USAMRIID. The detection system under development involves the attachment of antibodies to an optical fiber at high density. In addition, the immobilization must be achieved in a way which retains the antibody's ability to bind antigen. The functionality of the antibody will be tested through the binding of a labelled antigen. In the future, this assay could incorporate the antibodies developed by the Army for pathogens of particularly military concern.

3D silicon neural probe with integrated optical fibers for optogenetic modulation.

PubMed

Kim, Eric G R; Tu, Hongen; Luo, Hao; Liu, Bin; Bao, Shaowen; Zhang, Jinsheng; Xu, Yong

2015-07-21

Optogenetics is a powerful modality for neural modulation that can be useful for a wide array of biomedical studies. Penetrating microelectrode arrays provide a means of recording neural signals with high spatial resolution. It is highly desirable to integrate optics with neural probes to allow for functional study of neural tissue by optogenetics. In this paper, we report the development of a novel 3D neural probe coupled simply and robustly to optical fibers using a hollow parylene tube structure. The device shanks are hollow tubes with rigid silicon tips, allowing the insertion and encasement of optical fibers within the shanks. The position of the fiber tip can be precisely controlled relative to the electrodes on the shank by inherent design features. Preliminary in vivo rat studies indicate that these devices are capable of optogenetic modulation simultaneously with 3D neural signal recording.

Microelectromechanical apparatus for elevating and tilting a platform

DOEpatents

Miller, Samuel Lee; McWhorter, Paul Jackson; Rodgers, Murray Steven; Sniegowski, Jeffry J.; Barnes, Stephen M.

2003-04-08

A microelectromechanical (MEM) apparatus is disclosed which has a platform that can be elevated above a substrate and tilted at an arbitrary angle using a plurality of flexible members which support the platform and control its movement. Each flexible member is further controlled by one or more MEM actuators which act to bend the flexible member. The MEM actuators can be electrostatic comb actuators or vertical zip actuators, or a combination thereof. The MEM apparatus can include a mirror coating to form a programmable mirror for redirecting or switching one or more light beams for use in a projection display. The MEM apparatus with the mirror coating also has applications for switching light beams between optical fibers for use in a local area fiber optic network, or for use in fiber optic telecommunications or data communications systems.

Microelectromechanical apparatus for elevating and tilting a platform

DOEpatents

Miller, Samuel Lee; McWhorter, Paul Jackson; Rodgers, Murray Steven; Sniegowski, Jeffry J.; Barnes, Stephen M.

2004-07-06

A microelectromechanical (MEM) apparatus is disclosed which has a platform that can be elevated above a substrate and tilted at an arbitrary angle using a plurality of flexible members which support the platform and control its movement. Each flexible member is further controlled by one or more MEM actuators which act to bend the flexible member. The MEM actuators can be electrostatic comb actuators or vertical zip actuators, or a combination thereof. The MEM apparatus can include a mirror coating to form a programmable mirror for redirecting or switching one or more light beams for use in a projection display. The MEM apparatus with-the mirror coating also has applications for switching light beams between optical fibers for use in a local area fiber optic network, or for use in fiber optic telecommunications or data communications systems.

Microminiaturized minimally invasive intravascular micro-mechanical systems powered and controlled via fiber-optic cable

DOEpatents

Fitch, J.P.; Hagans, K.; Clough, R.; Matthews, D.L.; Lee, A.P.; Krulevitch, P.A.; Benett, W.J.; Silva, L. Da; Celliers, P.M.

1998-03-03

A micro-mechanical system for medical procedures is constructed in the basic form of a catheter having a distal end for insertion into and manipulation within a body and a near end providing for a user to control the manipulation of the distal end within the body. A fiber-optic cable is disposed within the catheter and having a distal end proximate to the distal end of the catheter and a near end for external coupling of laser light energy. A microgripper is attached to the distal end of the catheter and providing for the gripping or releasing of an object within the body. A laser-light-to-mechanical-power converter is connected to receive laser light from the distal end of the fiber-optic cable and connected to mechanically actuate the microgripper. 22 figs.

Fabrication of fiber-optic localized surface plasmon resonance sensor and its application to detect antibody-antigen reaction of interferon-gamma

NASA Astrophysics Data System (ADS)

Jeong, Hyeon-Ho; Erdene, Norov; Lee, Seung-Ki; Jeong, Dae-Hong; Park, Jae-Hyoung

2011-12-01

A fiber-optic localized surface plasmon (FO LSPR) sensor was fabricated by gold nanoparticles (Au NPs) immobilized on the end-face of an optical fiber. When Au NPs were formed on the end-face of an optical fiber by chemical reaction, Au NPs aggregation occurred and the Au NPs were immobilized in various forms such as monomers, dimers, trimers, etc. The component ratio of the Au NPs on the end-face of the fabricated FO LSPR sensor was slightly changed whenever the sensors were fabricated in the same condition. Including this phenomenon, the FO LSPR sensor was fabricated with high sensitivity by controlling the density of Au NPs. Also, the fabricated sensors were measured for the resonance intensity for the different optical systems and analyzed for the effect on sensitivity. Finally, for application as a biosensor, the sensor was used for detecting the antibody-antigen reaction of interferon-gamma.

Research of hydroelectric generating set low-frequency vibration monitoring system based on optical fiber sensing

NASA Astrophysics Data System (ADS)

Min, Li; Zhang, Xiaolei; Zhang, Faxiang; Sun, Zhihui; Li, ShuJuan; Wang, Meng; Wang, Chang

2017-10-01

In order to satisfy hydroelectric generating set low-frequency vibration monitoring, the design of Passive low-frequency vibration monitoring system based on Optical fiber sensing in this paper. The hardware of the system adopts the passive optical fiber grating sensor and unbalanced-Michelson interferometer. The software system is used to programming by Labview software and finishing the control of system. The experiment show that this system has good performance on the standard vibration testing-platform and it meets system requirements. The frequency of the monitoring system can be as low as 0.2Hz and the resolution is 0.01Hz.

Neural network-based system for pattern recognition through a fiber optic bundle

NASA Astrophysics Data System (ADS)

Gamo-Aranda, Javier; Rodriguez-Horche, Paloma; Merchan-Palacios, Miguel; Rosales-Herrera, Pablo; Rodriguez, M.

2001-04-01

A neural network based system to identify images transmitted through a Coherent Fiber-optic Bundle (CFB) is presented. Patterns are generated in a computer, displayed on a Spatial Light Modulator, imaged onto the input face of the CFB, and recovered optically by a CCD sensor array for further processing. Input and output optical subsystems were designed and used to that end. The recognition step of the transmitted patterns is made by a powerful, widely-used, neural network simulator running on the control PC. A complete PC-based interface was developed to control the different tasks involved in the system. An optical analysis of the system capabilities was carried out prior to performing the recognition step. Several neural network topologies were tested, and the corresponding numerical results are also presented and discussed.

Intelligent optical fiber sensor system for measurement of gas concentration

NASA Astrophysics Data System (ADS)

Pan, Jingming; Yin, Zongmin

1991-08-01

A measuring, controlling, and alarming system for the concentration of a gas or transparent liquid is described. In this system, a Fabry-Perot etalon with an optical fiber is used as the sensor, a charge-coupled device (CCD) is used as the photoelectric converter, and a single- chip microcomputer 8031 along with an interface circuit is used to measure the interference ring signal. The system has such features as real-time and on-line operation, continuous dynamic handling, and intelligent control.

LEOS Summer Topical Meetings (1991) on Spaceborne Photonics: Aerospace Applications of Lasers and Electro-Optics and Optical Millimeter-Wave Interactions: Measurements, Generation, Transmission and Control Held in Newport Beach, California on July 22-26, 1991

DTIC Science & Technology

1992-02-29

are co-boresighted with dual-axis Risley prisms which are mounted in the extension of the laser cavity at the periphery of the telescope primary...unwanted optical feedback into the lasers, the fiber was polished with a wedge angle of approximately 10 degrees. The fiber tip was brought to less

Gain statistics of a fiber optical parametric amplifier with a temporally incoherent pump.

PubMed

Xu, Y Q; Murdoch, S G

2010-03-15

We present an investigation of the statistics of the gain fluctuations of a fiber optical parametric amplifier pumped with a temporally incoherent pump. We derive a simple expression for the probability distribution of the gain of the amplified optical signal. The gain statistics are shown to be a strong function of the signal detuning and allow the possibility of generating optical gain distributions with controllable long-tails. Very good agreement is found between this theory and the experimentally measured gain distributions of an incoherently pumped amplifier.

Electro-optic architecture for servicing sensors and actuators in advanced aircraft propulsion systems

NASA Technical Reports Server (NTRS)

Poppel, G. L.; Glasheen, W. M.

1989-01-01

A detailed design of a fiber optic propulsion control system, integrating favored sensors and electro-optics architecture is presented. Layouts, schematics, and sensor lists describe an advanced fighter engine system model. Components and attributes of candidate fiber optic sensors are identified, and evaluation criteria are used in a trade study resulting in favored sensors for each measurand. System architectural ground rules were applied to accomplish an electro-optics architecture for the favored sensors. A key result was a considerable reduction in signal conductors. Drawings, schematics, specifications, and printed circuit board layouts describe the detailed system design, including application of a planar optical waveguide interface.

Optical fiber sensors for high temperature harsh environment applications

NASA Astrophysics Data System (ADS)

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

2010-04-01

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

Four channel Laser Firing Unit using laser diodes

NASA Technical Reports Server (NTRS)

Rosner, David, Sr.; Spomer, Edwin, Sr.

1994-01-01

This paper describes the accomplishments and status of PS/EDD's (Pacific Scientific/Energy Dynamics Division) internal research and development effort to prototype and demonstrate a practical four channel laser firing unit (LFU) that uses laser diodes to initiate pyrotechnic events. The LFU individually initiates four ordnance devices using the energy from four diode lasers carried over the fiber optics. The LFU demonstrates end-to-end optical built in test (BIT) capabilities. Both Single Fiber Reflective BIT and Dual Fiber Reflective BIT approaches are discussed and reflection loss data is presented. This paper includes detailed discussions of the advantages and disadvantages of both BIT approaches, all-fire and no-fire levels, and BIT detection levels. The following topics are also addressed: electronic control and BIT circuits, fiber optic sizing and distribution, and an electromechanical shutter type safe/arm device. This paper shows the viability of laser diode initiation systems and single fiber BIT for typing military applications.

Study of the technics of coating stripping and FBG writing on polyimide fiber

NASA Astrophysics Data System (ADS)

Song, ZhiQiang; Qi, HaiFeng; Ni, JiaSheng; Wang, Chang

2017-10-01

Compared with ordinary optical fiber, polyimide fiber has the characteristics of high temperature resistance and high strength, which has important application in the field of optical fiber sensing. The common methods of polyimide coating stripping were introduced in this paper, including high temperature stripping, chemical stripping and arc ablation. In order to meet the requirements of FBG writing technology, a method using argon ion laser ablation coating was proposed. The method can precisely control the stripping length of the coating and completely does not affect the tensile strength of the optical fiber. According to the experiment, the fabrication process of polyimide FBG is stripping-hydrogen loadingwriting. Under the same conditions, 10 FBG samples were fabricated with good uniformity of wavelength bandwidth and reflectivity. UV laser ablation of polyimide coating has been proved to be a safe, reliable and efficient method.

Surface Modification of Carbon Fiber Polymer Composites after Laser Structuring

NASA Astrophysics Data System (ADS)

Sabau, Adrian S.; Chen, Jian; Jones, Jonaaron F.; Hackett, Alexandra; Jellison, Gerald D.; Daniel, Claus; Warren, David; Rehkopf, Jackie D.

The increasing use of Carbon Fiber-reinforced Polymer matrix Composites (CFPC) as a lightweight material in automotive and aerospace industries requires the control of surface morphology. In this study, the composites surface was prepared by ablating the resin on the top fiber layer of the composite using an Nd:YAG laser. The CFPC specimens with T700S carbon fiber and Prepreg — T83 resin (epoxy) were supplied by Plasan Carbon Composites, Inc. as 4 ply thick, 0/90° plaques. The effect of laser fluence, scanning speed, and wavelength was investigated on the removal rate of the resin without an excessive damage of the fibers. In addition, resin ablation due to the power variation created by a laser interference technique is presented. Optical property measurements, optical micrographs, 3D imaging, and high-resolution optical profiler images were used to study the effect of the laser processing on surface morphology.

Detection of wavelengths in the visible range using fiber optic sensors

NASA Astrophysics Data System (ADS)

Díaz, Leonardo; Morales, Yailteh; Mattos, Lorenzo; Torres, Cesar O.

2013-11-01

This paper shows the design and implementation of a fiber optic sensor for detecting and identifying wavelengths in the visible range. The system consists of a diffuse optical fiber, a conventional laser diode 650nm, 2.5mW of power, an ambient light sensor LX1972, a PIC 18F2550 and LCD screen for viewing. The principle used in the detection of the lambda is based on specular reflection and absorption. The optoelectronic device designed and built used the absorption and reflection properties of the material under study, having as active optical medium a bifurcated optical fiber, which is optically coupled to an ambient light sensor, which makes the conversion of light signals to electricas, procedure performed by a microcontroller, which acquires and processes the signal. To verify correct operation of the assembly were utilized the color cards of sewing thread and nail polish as samples for analysis. This optoelectronic device can be used in many applications such as quality control of industrial processes, classification of corks or bottle caps, color quality of textiles, sugar solutions, polymers and food among others.

FLASH fly-by-light flight control demonstration results overview

NASA Astrophysics Data System (ADS)

Halski, Don J.

1996-10-01

The Fly-By-Light Advanced Systems Hardware (FLASH) program developed Fly-By-Light (FBL) and Power-By-Wire (PBW) technologies for military and commercial aircraft. FLASH consists of three tasks. Task 1 developed the fiber optic cable, connectors, testers and installation and maintenance procedures. Task 3 developed advanced smart, rotary thin wing and electro-hydrostatic (EHA) actuators. Task 2, which is the subject of this paper,l focused on integration of fiber optic sensors and data buses with cable plant components from Task 1 and actuators from Task 3 into centralized and distributed flight control systems. Both open loop and piloted hardware-in-the-loop demonstrations were conducted with centralized and distributed flight control architectures incorporating the AS-1773A optical bus, active hand controllers, optical sensors, optimal flight control laws in high speed 32-bit processors, and neural networks for EHA monitoring and fault diagnosis. This paper overviews the systems level testing conducted under the FLASH Flight Control task. Preliminary results are summarized. Companion papers provide additional information.

EC91-436-8

NASA Image and Video Library

1991-08-16

The National Aeronautics and Space Administration's Systems Research Aircraft (SRA), a highly modified F-18 jet fighter, during a research flight. The former Navy aircraft was flown by NASA's Dryden Flight Research Center at Edwards Air Force Base, California, to evaluate a number of experimental aerospace technologies in a multi-year, joint NASA/DOD/industry program. Among the more than 20 experiments flight-tested were several involving fiber optic sensor systems. Experiments developed by McDonnell-Douglas and Lockheed-Martin centered on installation and maintenace techniques for various types of fiber-optic hardware proposed for use in military and commercial aircraft, while a Parker-Hannifin experiment focused in alternative fiber-optic designs for position measurement sensors as well as operational experience in handling optical sensor systems. Other experiments flown on this testbed aircraft included electronically-controlled control surface actuators, flush air data collection systems, "smart" skin antennae and laser-based systems. Incorporation of one or more of these technologies in future aircraft and spacecraft could result in signifigant savings in weight, maintenance and overall cost.

Rapid fabrication of micro-nanometric tapered fiber lens and characterization by a novel scanning optical microscope with submicron resolution.

PubMed

Zheng, Shouguo; Zeng, Xinhua; Luo, Wei; Jradi, Safi; Plain, Jérôme; Li, Miao; Renaud-Goud, Philippe; Deturche, Régis; Wang, Zengfu; Kou, Jieting; Bachelot, Renaud; Royer, Pascal

2013-01-14

In numerous applications of optical scanning microscopy, a reference tapered fiber lens with high symmetry at sub-wavelength scale remains a challenge. Here, we demonstrate the ability to manufacture it with a wide range of geometry control, either for the length from several hundred nanometers to several hundred microns, or for the curvature radius from several tens of nanometers to several microns on the endface of a single mode fiber. On this basis, a scanning optical microscope has been developed, which allows for fast characterization of various sub-wavelength tapered fiber lenses. Focal position and depth of microlenses with different geometries have been determined to be ranged from several hundreds of nanometers to several microns. FDTD calculations are consistent with experimental results.

Multifunctional Polymer Nanofibers: UV Emission, Optical Gain, Anisotropic Wetting, and High Hydrophobicity for Next Flexible Excitation Sources

PubMed Central

2015-01-01

The use of UV light sources is highly relevant in many fields of science, being directly related to all those detection and diagnosis procedures that are based on fluorescence spectroscopy. Depending on the specific application, UV light-emitting materials are desired to feature a number of opto-mechanical properties, including brightness, optical gain for being used in laser devices, flexibility to conform with different lab-on-chip architectures, and tailorable wettability to control and minimize their interaction with ambient humidity and fluids. In this work, we introduce multifunctional, UV-emitting electrospun fibers with both optical gain and greatly enhanced anisotropic hydrophobicity compared to films. Fibers are described by the onset of a composite wetting state, and their arrangement in uniaxial arrays further favors liquid directional control. The low gain threshold, optical losses, plastic nature, flexibility, and stability of these UV-emitting fibers make them interesting for building light-emitting devices and microlasers. Furthermore, the anisotropic hydrophobicity found is strongly synergic with optical properties, reducing interfacial interactions with liquids and enabling smart functional surfaces for droplet microfluidic and wearable applications. PMID:26401889

Laser Optics/Combustion Diagnostics.

DTIC Science & Technology

1986-07-01

of Blackbody at Various Temperatures (K). . . 153 21 Transmission Attenuation of Quartz Fiber ... ............ .. 155 22 Schematic Diagram of Receiver...transfer pro- time-multiplexed via different lengths of fiber -optic cable to gram (machine code) of the TN- 1710 controls the handshak- a single...linewidths depend upon temperature, pressure, and , composition of the medium as well as the J value of the line. Collisional effects, as demonstrated for

Window flaw detection by backscatter lighting

NASA Technical Reports Server (NTRS)

Crockett, L. K.; Minton, F. R.

1978-01-01

Portable fiber-optic probe detects tiny flaws in transparent materials. Probe transmits light through surface to illuminate interior of material by backscattering off its edges. Light-sensitive contact paper records scratch pattern. Technique can be used for rapid visual checks. Flexible fiber optics are safely used in explosive or flammable areas; they present no hazard of breakage or contamination in controlled environments.

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.

On the importance of simultaneous infrared/fiber-optic temperature monitoring in the microwave-assisted synthesis of ionic liquids.

PubMed

Obermayer, David; Kappe, C Oliver

2010-01-07

The temperature profiles obtained from both an external infrared and internal fiber-optic sensor were compared for heating and synthesizing the ionic liquid 1-butyl-3-methylimidazolium bromide (bmimBr) under microwave conditions. Utilizing a single-mode microwave reactor that allows simultaneous infrared/fiber-optic temperature measurements, significant differences between the two methods of temperature monitoring were revealed. Due to the strong microwave absorptivity of ionic liquids and the delay experienced in monitoring temperature on the outer surface of a heavy-walled glass vial, external infrared temperature sensors can not be used to accurately control the temperature in the heating of ionic liquids under microwave conditions. The use of internal fiber-optic probes allows the monitoring and control of the heating behavior in a much better way. In order to prevent the strong exotherm in the synthesis of bmimBr under microwave conditions the use of a reaction vessel made out of silicon carbide is the method of choice. Because of the high thermal conductivity and effusivity of silicon carbide, the heat generated during the ionic liquid formation is efficiently exchanged with the comparatively cool air in the microwave cavity via the silicon carbide ceramic.

Monitoring industrial facilities using principles of integration of fiber classifier and local sensor networks

NASA Astrophysics Data System (ADS)

Korotaev, Valery V.; Denisov, Victor M.; Rodrigues, Joel J. P. C.; Serikova, Mariya G.; Timofeev, Andrey V.

2015-05-01

The paper deals with the creation of integrated monitoring systems. They combine fiber-optic classifiers and local sensor networks. These systems allow for the monitoring of complex industrial objects. Together with adjacent natural objects, they form the so-called geotechnical systems. An integrated monitoring system may include one or more spatially continuous fiber-optic classifiers based on optic fiber and one or more arrays of discrete measurement sensors, which are usually combined in sensor networks. Fiber-optic classifiers are already widely used for the control of hazardous extended objects (oil and gas pipelines, railways, high-rise buildings, etc.). To monitor local objects, discrete measurement sensors are generally used (temperature, pressure, inclinometers, strain gauges, accelerometers, sensors measuring the composition of impurities in the air, and many others). However, monitoring complex geotechnical systems require a simultaneous use of continuous spatially distributed sensors based on fiber-optic cable and connected local discrete sensors networks. In fact, we are talking about integration of the two monitoring methods. This combination provides an additional way to create intelligent monitoring systems. Modes of operation of intelligent systems can automatically adapt to changing environmental conditions. For this purpose, context data received from one sensor (e.g., optical channel) may be used to change modes of work of other sensors within the same monitoring system. This work also presents experimental results of the prototype of the integrated monitoring system.

Compact and high-efficiency device for Raman scattering measurement using optical fibers.

PubMed

Mitsui, Tadashi

2014-11-01

We describe the design and development of a high-efficiency optical measurement device for operation within the small bore of a high-power magnet at low temperature. For the high-efficiency measurement of light emitted from this small region, we designed a compact confocal optics with lens focusing and tilting systems, and used a piezodriven translation stage that allows micron-scale focus control of the sample position. We designed a measurement device that uses 10 m-long optical fibers in order to avoid the influence of mechanical vibration and magnetic field leakage of high-power magnets, and we also describe a technique for minimizing the fluorescence signal of optical fibers. The operation of the device was confirmed by Raman scattering measurements of monolayer graphene on quartz glass with a high signal-to-noise ratio.

Interferometer design and controls for pulse stacking in high power fiber lasers

NASA Astrophysics Data System (ADS)

Wilcox, Russell; Yang, Yawei; Dahlen, Dar; Xu, Yilun; Huang, Gang; Qiang, Du; Doolittle, Lawrence; Byrd, John; Leemans, Wim; Ruppe, John; Zhou, Tong; Sheikhsofla, Morteza; Nees, John; Galvanauskas, Almantas; Dawson, Jay; Chen, Diana; Pax, Paul

2017-03-01

In order to develop a design for a laser-plasma accelerator (LPA) driver, we demonstrate key technologies that enable fiber lasers to produce high energy, ultrafast pulses. These technologies must be scalable, and operate in the presence of thermal drift, acoustic noise, and other perturbations typical of an operating system. We show that coherent pulse stacking (CPS), which requires optical interferometers, can be made robust by image-relaying, multipass optical cavities, and by optical phase control schemes that sense pulse train amplitudes from each cavity. A four-stage pulse stacking system using image-relaying cavities is controlled for 14 hours using a pulse-pattern sensing algorithm. For coherent addition of simultaneous ultrafast pulses, we introduce a new scheme using diffractive optics, and show experimentally that four pulses can be added while a preserving pulse width of 128 fs.

Controlled generation of high-intensity optical rogue waves by induced modulation instability

PubMed Central

Zhao, Saili; Yang, Hua; Chen, Nengsong; Zhao, Chujun

2017-01-01

Optical rogue waves are featured as the generation of high amplitude events at low probability in optical systems. Moreover, the formation of optical rogue waves is unpredictable and transient in photonic crystal fibers. In this paper, we put forward a method to generate high-intensity optical rogue waves in a more controlled way based on induced modulation instability, which can suppress the noise effect and hence play a leading role in the process of pulse evolution. Our numerical simulations indicate that the generation of rogue wave can be controlled when seeding at the optimal modulation frequency and the intensity of rogue wave can be enhanced with appropriate modulation depth. Further, high-intensity rogue wave can also be ejected in the fiber with a shorter propagation length by regulating the modulation depth. These results all provide a better understanding of optical rogue wave, which can contribute to the generation of tunable long-wavelength spectral components and selective excitation of mid-infrared supercontinuum. PMID:28051149

Controlled generation of high-intensity optical rogue waves by induced modulation instability.

PubMed

Zhao, Saili; Yang, Hua; Chen, Nengsong; Zhao, Chujun

2017-01-04

Optical rogue waves are featured as the generation of high amplitude events at low probability in optical systems. Moreover, the formation of optical rogue waves is unpredictable and transient in photonic crystal fibers. In this paper, we put forward a method to generate high-intensity optical rogue waves in a more controlled way based on induced modulation instability, which can suppress the noise effect and hence play a leading role in the process of pulse evolution. Our numerical simulations indicate that the generation of rogue wave can be controlled when seeding at the optimal modulation frequency and the intensity of rogue wave can be enhanced with appropriate modulation depth. Further, high-intensity rogue wave can also be ejected in the fiber with a shorter propagation length by regulating the modulation depth. These results all provide a better understanding of optical rogue wave, which can contribute to the generation of tunable long-wavelength spectral components and selective excitation of mid-infrared supercontinuum.

Range Imaging without Moving Parts

NASA Technical Reports Server (NTRS)

Blair, J. Bryan; Scott, V. Stanley, III; Ramos-Izquierdo, Luis

2008-01-01

Range-imaging instruments of a type now under development are intended to generate the equivalent of three-dimensional images from measurements of the round-trip times of flight of laser pulses along known directions. These instruments could also provide information on characteristics of targets, including roughnesses and reflectivities of surfaces and optical densities of such semi-solid objects as trees and clouds. Unlike in prior range-imaging instruments based on times of flight along known directions, there would be no moving parts; aiming of the laser beams along the known directions would not be accomplished by mechanical scanning of mirrors, prisms, or other optical components. Instead, aiming would be accomplished by using solid-state devices to switch input and output beams along different fiber-optic paths. Because of the lack of moving parts, these instruments could be extraordinarily reliable, rugged, and long-lasting. An instrument of this type would include an optical transmitter that would send out a laser pulse along a chosen direction to a target. An optical receiver coaligned with the transmitter would measure the temporally varying intensity of laser light reflected from the target to determine the distance and surface characteristics of the target. The transmitter would be a combination of devices for generating precise directional laser illumination. It would include a pulsed laser, the output of which would be coupled into a fiber-optic cable with a fan-out and solid-state optical switches that would enable switching of the laser beam onto one or more optical fibers terminated at known locations in an array on a face at the focal plane of a telescope. The array would be imaged by the telescope onto the target space. The receiver optical system could share the aforementioned telescope with the transmitter or could include a separate telescope aimed in the same direction as that of the transmitting telescope. In either case, light reflected from the target would be focused by the receiver optical system onto an array of optical fibers matching the array in the transmitter. These optical fibers would couple the received light to one or more photodetector( s). Optionally, the receiver could include solid-state optical switches for choosing which optical fiber(s) would couple light to the photodetector(s). This instrument architecture is flexible and can be optimized for a wide variety of applications and levels of performance. For example, it is scalable to any number of pixels and pixel resolutions and is compatible with a variety of ranging and photodetection methodologies, including, for example, ranging by use of modulated (including pulsed and encoded) light signals. The use of fixed arrays of optical fibers to generate controlled illumination patterns would eliminate the mechanical complexity and much of the bulk of optomechanical scanning assemblies. Furthermore, digital control of the selection of the fiber-optic pathways for the transmitted beams could afford capabilities not seen in previous three-dimensional range-imaging systems. Instruments of this type could be specialized for use as, for example, proximity detectors, three-dimensional robotic vision systems, airborne terrain-mapping systems, and inspection systems.

Narrow linewidth comb realized with a mode-locked fiber laser using an intra-cavity waveguide electro-optic modulator for high-speed control.

PubMed

Iwakuni, Kana; Inaba, Hajime; Nakajima, Yoshiaki; Kobayashi, Takumi; Hosaka, Kazumoto; Onae, Atsushi; Hong, Feng-Lei

2012-06-18

We have developed an optical frequency comb using a mode-locked fiber ring laser with an intra-cavity waveguide electro-optic modulator controlling the optical length in the laser cavity. The mode-locking is achieved with a simple ring configuration and a nonlinear polarization rotation mechanism. The beat note between the laser and a reference laser and the carrier envelope offset frequency of the comb were simultaneously phase locked with servo bandwidths of 1.3 MHz and 900 kHz, respectively. We observed an out-of-loop beat between two identical combs, and obtained a coherent δ-function peak with a signal to noise ratio of 70 dB/Hz.

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.

Micro particle launcher/cleaner based on optical trapping technology.

PubMed

Liu, Zhihai; Liang, Peibo; Zhang, Yu; Zhang, Yaxun; Zhao, Enming; Yang, Jun; Yuan, Libo

2015-04-06

Efficient and controllable launching function of an optical tweezers is a challenging task. We present and demonstrate a novel single fiber optical tweezers which can trap and launch (clean) a target polystyrene (PS) microsphere (diameter~10μm) with independent control by using two wavelengths beams: 980nm and 1480nm. We employ 980nm laser beam to trap the target PS microsphere by molding the fiber tip into a special tapered-shape; and we employ 1480nm laser beam to launch the trapped PS microsphere with a certain velocity by using the thermophoresis force generated from the thermal effect due to the high absorption of the 1480nm laser beams in water. When the launching force is smaller than the trapping force, the PS microsphere will be trapped near the fiber tip, and the launching force will blow away other PS microspheres in the workspace realizing the cleaning function; When the launching force is larger than the trapping force, the trapped PS microsphere will be launched away from the fiber tip with a certain velocity and towards a certain direction, realizing the launching function. The launching velocity, acceleration and the distance can be measured by detecting the interference signals generated from the PS microsphere surface and the fiber tip end-face. This PS microsphere launching and cleaning functions expanded new features of single fiber optical tweezers, providing for the possibility of more practical applications in the micro manipulation research fields.

Medical catheters thermally manipulated by fiber optic bundles

DOEpatents

Chastagner, P.

1992-10-06

A maneuverable medical catheter comprising a flexible tube having a functional tip is described. The catheter is connected to a control source. The functional tip of the catheter carries a plurality of temperature activated elements arranged in parallel and disposed about the functional tip and held in spaced relation at each end. These elements expand when they are heated. A plurality of fiber optic bundles, each bundle having a proximal end attached to the control source and a distal end attached to one of the elements carry light into the elements where the light is absorbed as heat. By varying the optic fiber that is carrying the light and the intensity of the light, the bending of the elements can be controlled and thus the catheter steered. In an alternate embodiment, the catheter carries a medical instrument for gathering a sample of tissue. The instrument may also be deployed and operated by thermal expansion and contraction of its moving parts. 10 figs.

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.

Specialty flat-top beam delivery fibers with controlled beam parameter product

NASA Astrophysics Data System (ADS)

Jollivet, C.; Farley, K.; Conroy, M.; Abramczyk, J.; Belke, S.; Becker, F.; Tankala, K.

2016-03-01

Beam delivery fibers have been used widely for transporting the optical beams from the laser to the subject of irradiation in a variety of markets including industrial, medical and defense applications. Standard beam delivery fibers range from 50 to 1500 μm core diameter and are used to guide CW or pulsed laser light, generated by solid state, fiber or diode lasers. Here, we introduce a novel fiber technology capable of simultaneously controlling the beam profile and the angular divergence of single-mode (SM) and multi-mode (MM) beams using a single-optical fiber. Results of beam transformation from a SM to a MM beam with flat-top intensity profile are presented in the case of a controlled BPP at 3.8 mm*mrad. The scaling capabilities of this flat-top fiber design to achieve a range of BPP values while ensuring a flat-top beam profile are discussed. In addition, we demonstrate, for the first time to the best of our knowledge, the homogenizer capabilities of this novel technology, able to transform random MM beams into uniform flat-top beam profiles with very limited impact on the beam brightness. This study is concluded with a discussion on the scalability of this fiber technology to fit from 50 up to 1500 μm core fibers and its potential for a broader range of applications.

Opto-mechanical design of the G-CLEF flexure control camera system

NASA Astrophysics Data System (ADS)

Oh, Jae Sok; Park, Chan; Kim, Jihun; Kim, Kang-Min; Chun, Moo-Young; Yu, Young Sam; Lee, Sungho; Nah, Jakyoung; Park, Sung-Joon; Szentgyorgyi, Andrew; McMuldroch, Stuart; Norton, Timothy; Podgorski, William; Evans, Ian; Mueller, Mark; Uomoto, Alan; Crane, Jeffrey; Hare, Tyson

2016-08-01

The GMT-Consortium Large Earth Finder (G-CLEF) is the very first light instrument of the Giant Magellan Telescope (GMT). The G-CLEF is a fiber feed, optical band echelle spectrograph that is capable of extremely precise radial velocity measurement. KASI (Korea Astronomy and Space Science Institute) is responsible for Flexure Control Camera (FCC) included in the G-CLEF Front End Assembly (GCFEA). The FCC is a kind of guide camera, which monitors the field images focused on a fiber mirror to control the flexure and the focus errors within the GCFEA. The FCC consists of five optical components: a collimator including triple lenses for producing a pupil, neutral density filters allowing us to use much brighter star as a target or a guide, a tent prism as a focus analyzer for measuring the focus offset at the fiber mirror, a reimaging camera with three pair of lenses for focusing the beam on a CCD focal plane, and a CCD detector for capturing the image on the fiber mirror. In this article, we present the optical and mechanical FCC designs which have been modified after the PDR in April 2015.

The cervical cancer detection system based on an endoscopic rotary probe

NASA Astrophysics Data System (ADS)

Yang, Yanshuang; Hou, Qiang; Zhao, Huijuan; Qin, Zhuanping; Gao, Feng

2012-03-01

To acquire the optical diffuse tomographic image of the cervix, a novel endoscopic rotary probe is designed and the frequency domain measurement system is developed. The finite element method and Gauss-Newton method are proposed to reconstruct the image of the phantom. In the optical diffuse tomographic imaging of the cervix, an endoscopic probe is needed and the detection of light at different separation to the irradiation spot is necessary. To simplify the system, only two optical fibers are adopted for light irradiation and collection, respectively. Two small stepper motors are employed to control the rotation of the incident fiber and the detection fiber, respectively. For one position of source fiber, the position of the detection fiber is changed from -61.875° to -50.625° and 50.625° to 61.875° to the source fiber, respectively. Then, the position of the source fiber is changed to another preconcerted position, which deviates the precious source position in an angle of 11.25°, and the detection fiber rotates within the above angles. To acquire the efficient irradiation and collection of the light, a gradient-index (GRIN) lens is connected at the head of the optical fiber. The other end of the GRIN lens is cut to 45°. With this design, light from optical fiber is reflected to the cervix wall, which is perpendicular to the optical fiber or vice versa. Considering the cervical size, the external diameter of the endoscopic probe is made to 20mm. A frequency domain (FD) near-infrared diffuse system is developed aiming at the detection of early cervical cancer, which modulates the light intensity in radio frequency and measures the amplitude attenuation and the phase delay of the diffused light using heterodyne detection. Phantom experiment results demonstrate that the endoscopic rotary scan probe and the system perform well in the endoscopic measurement.

Manhattan Solar Cannon

NASA Astrophysics Data System (ADS)

Treffers, Richard R.; Loisos, George; Ubbelohde, Susan; Douglas, Susanna; Pintos, Eduardo; Mulherin, James; Pasley, David

2015-01-01

We describe a 2.4 m hexagonal solar collector atop a Manhattan office building used for a solar / arts project. The collector uses an afocal design to concentrate the sunlight into a 0.6 m diameter beam which is directed by mirrors into a 80 m long fiber optic sculpture which descends an interior stairwell. The collector is fully steerable and follows the sun each day robotically. The control system and the optical design of the collector as well as the fiber optic sculpture will be discussed.

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.

An optimized routing algorithm for the automated assembly of standard multimode ribbon fibers in a full-mesh optical backplane

NASA Astrophysics Data System (ADS)

Basile, Vito; Guadagno, Gianluca; Ferrario, Maddalena; Fassi, Irene

2018-03-01

In this paper a parametric, modular and scalable algorithm allowing a fully automated assembly of a backplane fiber-optic interconnection circuit is presented. This approach guarantees the optimization of the optical fiber routing inside the backplane with respect to specific criteria (i.e. bending power losses), addressing both transmission performance and overall costs issues. Graph theory has been exploited to simplify the complexity of the NxN full-mesh backplane interconnection topology, firstly, into N independent sub-circuits and then, recursively, into a limited number of loops easier to be generated. Afterwards, the proposed algorithm selects a set of geometrical and architectural parameters whose optimization allows to identify the optimal fiber optic routing for each sub-circuit of the backplane. The topological and numerical information provided by the algorithm are then exploited to control a robot which performs the automated assembly of the backplane sub-circuits. The proposed routing algorithm can be extended to any array architecture and number of connections thanks to its modularity and scalability. Finally, the algorithm has been exploited for the automated assembly of an 8x8 optical backplane realized with standard multimode (MM) 12-fiber ribbons.

Theoretical modeling of a coupled plasmon waveguide resonance sensor based on multimode optical fiber

NASA Astrophysics Data System (ADS)

Liu, Kun; Xue, Meng; Jiang, Junfeng; Wang, Tao; Chang, Pengxiang; Liu, Tiegen

2018-03-01

A coupled plasmon waveguide resonance (CPWR) sensor based on metal/dielectric-coated step index multimode optical fiber is proposed. Theoretical simulations using the four-layer Fresnel equations based on a bi-dimensional optical fiber model were implemented on four structures: Ag-ZnO, Au-ZnO, Ag-TiO2 and Au-TiO2. By controlling the thickness of dielectric layer, we managed to manipulate the CPWR resonance wavelengths. When a CPWR resonance dip is in the short wavelength region, it is insensitive to the change of surrounding refractive index (SRI) and can be used as a reference to improve the sensing accuracy of surface plasmon resonance (SPR) mode. With the increase of the thickness of the dielectric layer, the CPWR resonance dips shift to longer wavelength and the corresponding sensitivities increase. When the 1st CPWR resonance wavelength is near 1550 nm and SRI is around 1.333, the sensitivities of four structures reach 1360.61 nm/RIU, 1375.76 nm/RIU, 1048.48 nm/RIU and 1015.15 nm/RIU, respectively. The values are close to that of the conventional SPR optical fiber sensor while the spectral bandwidths of the optical fiber CPWR sensors are narrower.

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.

Optical fiber ultrasound transmitter with electrospun carbon nanotube-polymer composite

NASA Astrophysics Data System (ADS)

Poduval, Radhika K.; Noimark, Sacha; Colchester, Richard J.; Macdonald, Thomas J.; Parkin, Ivan P.; Desjardins, Adrien E.; Papakonstantinou, Ioannis

2017-05-01

All-optical ultrasound transducers are promising for imaging applications in minimally invasive surgery. In these devices, ultrasound is transmitted and received through laser modulation, and they can be readily miniaturized using optical fibers for light delivery. Here, we report optical ultrasound transmitters fabricated by electrospinning an absorbing polymer composite directly onto the end-face of optical fibers. The composite coating consisting of an aqueous dispersion of multi-walled carbon nanotubes (MWCNTs) in polyvinyl alcohol was directly electrospun onto the cleaved surface of a multimode optical fiber and subsequently dip-coated with polydimethylsiloxane (PDMS). This formed a uniform nanofibrous absorbing mesh over the optical fiber end-face wherein the constituent MWCNTs were aligned preferentially along individual nanofibers. Infiltration of the PDMS through this nanofibrous mesh onto the underlying substrate was observed and the resulting composites exhibited high optical absorption (>97%). Thickness control from 2.3 μm to 41.4 μm was obtained by varying the electrospinning time. Under laser excitation with 11 μJ pulse energy, ultrasound pressures of 1.59 MPa were achieved at 1.5 mm from the coatings. On comparing the electrospun ultrasound transmitters with a dip-coated reference fabricated using the same constituent materials and possessing identical optical absorption, a five-fold increase in the generated pressure and wider bandwidth was observed. The electrospun transmitters exhibited high optical absorption, good elastomer infiltration, and ultrasound generation capability in the range of pressures used for clinical pulse-echo imaging. All-optical ultrasound probes with such transmitters fabricated by electrospinning could be well-suited for incorporation into catheters and needles for diagnostics and therapeutic applications.

Demonstration of a stand-alone cylindrical fiber coil for optical amplifiers

NASA Astrophysics Data System (ADS)

Laxton, Steven R.; Bravo, Tyler; Madsen, Christi K.

2015-08-01

The design, fabrication and measurement of a cylindrical fiber coil structure is presented that has applications for compact fiber-optic amplifiers. A multimode fiber is used as a surrogate for a dual clad, rare-earth doped fiber for coil fabrication and optical testing. A ray trace algorithm, written in Python, was used to simulate the behavior of light travelling along the waveguide path. An in-house fabrication method was developed using 3D printed parts designed in SolidWorks and assembled with Arduino-controlled stepper motors for coil winding. Ultraviolet-cured epoxy was used to bind the coils into a rigid cylinder. Bend losses are introduced by the coil, and a measurement of the losses for two coil lengths was obtained experimentally. The measurements confirm that bend losses through a multimode fiber, representative of pump light propagating in a dual-clad rare-earth doped fiber, are relatively wavelength independent over a large spectral range and that higher order modes are extinguished quickly while lower order modes transmit through the windings with relatively low loss.

Thermal and chemical treatment of polymer optical fiber Bragg grating sensors for enhanced mechanical sensitivity

NASA Astrophysics Data System (ADS)

Pospori, A.; Marques, C. A. F.; Sáez-Rodríguez, D.; Nielsen, K.; Bang, O.; Webb, D. J.

2017-07-01

An investigation of the thermal annealing effects on the strain, stress, and force sensitivities of polymer optical fiber Bragg grating sensors is performed. We demonstrate for the first time that the fiber annealing can enhance both stress and force sensitivities of Bragg grating sensors, with the possible cause being the molecular relaxation of the polymer when fiber is raised above the β -transition temperature. A simple, cost-effective, but well controlled method for fiber annealing is also presented in this work. In addition, the effects of chemical etching on the strain, stress, and force sensitivities have been investigated. Results show that fiber etching too can increase the force sensitivity, and it can also affect the strain and stress sensitivities of the Bragg grating sensors.

Infrared fiber optic temperature monitoring of biological tissues heated in a microwave oven

NASA Astrophysics Data System (ADS)

Belotserkovsky, Edward; Ashkenasy, Y.; Shenfeld, Ofer; Drizlikh, S.; Zur, Albert; Katzir, Abraham

1993-05-01

The heating of tissue by microwave radiation has attained a place of importance in various medical fields such as the treatment of malignancies, urinary retention and hypothermia. Accurate temperature measurements in these treated tissues is important for treatment planning and for the control of the heating process. It is also important to be able to measure spacial temperature distribution in the tissues because they are heated in a non uniform way by the microwave radiation. Fiber optic radiometry makes possible accurate temperature measurement in the presence of microwave radiation and does not require contact with the tissue. Using a IR silver halide fiber optic radiometric temperature sensor we obtained accurate temperature measurements of tissues heated by microwave, enabling us to control the heating process in all regions of the tissue. We also performed temperature mapping of the heated tissues and demonstrated the non-uniform temperature distributions in them.

Disposable cartridge biosensor platform for portable diagnostics

NASA Astrophysics Data System (ADS)

Yaras, Yusuf S.; Cakmak, Onur; Gunduz, Ali B.; Saglam, Gokhan; Olcer, Selim; Mostafazadeh, Aref; Baris, Ibrahim; Civitci, Fehmi; Yaralioglu, Goksen G.; Urey, Hakan

2017-03-01

We developed two types of cantilever-based biosensors for portable diagnostics applications. One sensor is based on MEMS cantilever chip mounted in a microfluidic channel and the other sensor is based on a movable optical fiber placed across a microfluidic channel. Both types of sensors were aimed at direct mechanical measurement of coagulation time in a disposable cartridge using plasma or whole blood samples. There are several similarities and also some important differences between the MEMS based and the optical fiber based solutions. The aim of this paper is to provide a comparison between the two solutions and the results. For both types of sensors, actuation of the cantilever or the moving fiber is achieved using an electro coil and the readout is optical. Since both the actuation and sensing are remote, no electrical connections are required for the cartridge. Therefore it is possible to build low cost disposable cartridges. The reader unit for the cartridge contains light sources, photodetectors, the electro coil, a heater, analog electronics, and a microprocessor. The reader unit has different optical interfaces for the cartridges that have MEMS cantilevers and moving fibers. MEMS based platform has better sensitivity but optomechanical alignment is a challenge and measurements with whole blood were not possible due to high scattering of light by the red blood cells. Fiber sensor based platform has relaxed optomechanical tolerances, ease of manufacturing, and it allows measurements in whole blood. Both sensors were tested using control plasma samples for activated-Partial-Thromboplastin-Time (aPTT) measurements. Control plasma test results matched with the manufacturer's datasheet. Optical fiber based system was tested for aPTT tests with human whole blood samples and the proposed platform provided repeatable test results making the system method of choice for portable diagnostics.

Dynamics analysis of microsphere in a dual-beam fiber-optic trap with transverse offset.

PubMed

Chen, Xinlin; Xiao, Guangzong; Luo, Hui; Xiong, Wei; Yang, Kaiyong

2016-04-04

A comprehensive dynamics analysis of microsphere has been presented in a dual-beam fiber-optic trap with transverse offset. As the offset distance between two counterpropagating beams increases, the motion type of the microsphere starts with capture, then spiral motion, then orbital rotation, and ends with escape. We analyze the transformation process and mechanism of the four motion types based on ray optics approximation. Dynamic simulations show that the existence of critical offset distances at which different motion types transform. The result is an important step toward explaining physical phenomena in a dual-beam fiber-optic trap with transverse offset, and is generally applicable to achieving controllable motions of microspheres in integrated systems, such as microfluidic systems and lab-on-a-chip systems.

Optical arbitrary waveform generation based on multi-wavelength semiconductor fiber ring laser

NASA Astrophysics Data System (ADS)

Li, Peili; Ma, Xiaolu; Shi, Weihua; Xu, Enming

2017-09-01

A new scheme of generating optical arbitrary waveforms based on multi-wavelength semiconductor fiber ring laser (SFRL) is proposed. In this novel scheme, a wide and flat optical frequency comb (OFC) is provided directly by multi-wavelength SFRL, whose central frequency and comb spacing are tunable. OFC generation, de-multiplexing, amplitude and phase modulation, and multiplexing are implementing in an intensity and phase tunable comb filter, as induces the merits of high spectral coherence, satisfactory waveform control and low system loss. By using the mode couple theory and the transfer matrix method, the theoretical model of the scheme is established. The impacts of amplitude control, phase control, number of spectral line, and injection current of semiconductor optical amplifier (SOA) on the waveform similarity are studied using the theoretical model. The results show that, amplitude control and phase control error should be smaller than 1% and 0.64% respectively to achieve high similarity. The similarity of the waveform is improved with the increase of the number of spectral line. When the injection current of SOA is in a certain range, the optical arbitrary waveform reaches a high similarity.

Coagulation measurement from whole blood using vibrating optical fiber in a disposable cartridge

NASA Astrophysics Data System (ADS)

Yaraş, Yusuf Samet; Gündüz, Ali Bars; Saǧlam, Gökhan; Ölçer, Selim; Civitçi, Fehmi; Baris, İbrahim; Yaralioǧlu, Göksenin; Urey, Hakan

2017-11-01

In clinics, blood coagulation time measurements are performed using mechanical measurements with blood plasma. Such measurements are challenging to do in a lab-on-a-chip (LoC) system using a small volume of whole blood. Existing LoC systems use indirect measurement principles employing optical or electrochemical methods. We developed an LoC system using mechanical measurements with a small volume of whole blood without requiring sample preparation. The measurement is performed in a microfluidic channel where two fibers are placed inline with a small gap in between. The first fiber operates near its mechanical resonance using remote magnetic actuation and immersed in the sample. The second fiber is a pick-up fiber acting as an optical sensor. The microfluidic channel is engineered innovatively such that the blood does not block the gap between the vibrating fiber and the pick-up fiber, resulting in high signal-to-noise ratio optical output. The control plasma test results matched well with the plasma manufacturer's datasheet. Activated-partial-thromboplastin-time tests were successfully performed also with human whole blood samples, and the method is proven to be effective. Simplicity of the cartridge design and cost of readily available materials enable a low-cost point-of-care device for blood coagulation measurements.

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.

High Efficiency Coupling of Optical Fibres with SU8 Micro-droplet Using Laser Welding Process

NASA Astrophysics Data System (ADS)

Yardi, Seema; Gupta, Ankur; Sundriyal, Poonam; Bhatt, Geeta; Kant, Rishi; Boolchandani, D.; Bhattacharya, Shantanu

2016-09-01

Apart from micro- structure fabrication, ablation, lithography etc., lasers find a lot of utility in various areas like precision joining, device fabrication, local heat delivery for surface texturing and local change of microstructure fabrication of standalone optical micro-devices (like microspheres, micro-prisms, micro-scale ring resonators, optical switches etc). There is a wide utility of such systems in chemical/ biochemical diagnostics and also communications where the standalone optical devices exist at a commercial scale but chip based devices with printed optics are necessary due to coupling issues between printed structures and external optics. This paper demonstrates a novel fabrication strategy used to join standalone optical fibres to microchip based printed optics using a simple SU8 drop. The fabrication process is deployed for fiber to fiber optical coupling and coupling between fiber and printed SU-8 waveguides. A CO2 laser is used to locally heat the coupling made up of SU8 material. Optimization of various dimensional parameters using design of experiments (DOE) on the bonded assembly has been performed as a function of laser power, speed, cycle control, spot size so on so forth. Exclusive optical [RF] modelling has been performed to estimate the transmissibility of the optical fibers bonded to each other on a surface with SU8. Our studies indicate the formation of a Whispering gallery mode (WGM) across the micro-droplet leading to high transmissibility of the signal. Through this work we have thus been able to develop a method of fabrication for optical coupling of standalone fibers or coupling of on-chip optics with off-chip illumination/detection.

Fiberoptics technology and its application to propulsion control systems

NASA Technical Reports Server (NTRS)

Baumbick, R. J.

1983-01-01

Current work on optical sensors and optically controlled actuators for use in air-breathing engine control systems is reviewed with particular reference to the design and operation of several new fiber-optic devices. These include a tachometer, a rotary position encoder, a Fabry-Perot interferometer and a rare-earth sensor for measuring engine gas temperatures, a high-temperature photoswitch designed for the range -55 to 260 C, and optical cables and connectors. The advantages of optics over conventional wire systems used for sensing and actuator control are briefly discussed.

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.

Small Business Innovations

NASA Technical Reports Server (NTRS)

1996-01-01

Under a Small Business Innovation Research (SBIR) contract to Kennedy Space Center, EIC Laboratories invented a Raman Spectrograph with fiber optic sampling for space applications such as sensing hazardous fuel vapors and making on-board rapid analyses of chemicals and minerals. Raman spectroscopy is a laser-based measurement technique that provides through a unique vibrational spectrum a molecular 'fingerprint,' and can function in aqueous environments. EIC combined optical fiber technology with Raman methods to develop sensors that can be operated at a distance from the spectrographic analysis instruments and the laser excitation source. EIC refined and commercialized the technology to create the Fiber Optic Raman Spectrograph and the RamanProbe. Commercial applications range from process control to monitoring hazardous materials.

Development and Ground-Test Validation of Fiber Optic Sensor Attachment Techniques for Hot Structures Applications

NASA Technical Reports Server (NTRS)

Piazza, Anthony; Hudson, Larry D.; Richards, W. Lance

2005-01-01

Fiber Optic Strain Measurements: a) Successfully attached silica fiber optic sensors to both metallics and composites; b) Accomplished valid EFPI strain measurements to 1850 F; c) Successfully attached EFPI sensors to large scale hot-structures; and d) Attached and thermally validated FBG bond and epsilon(sub app). Future Development a) Improve characterization of sensors on C-C and C-SiC substrates; b) Apply application to other composites such as SiC-SiC; c) Assist development of interferometer based Sapphire sensor currently being conducted under a Phase II SBIR; and d) Complete combined thermal/mechanical testing of FBG on composite substrates in controlled laboratory environment.

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

Radially polarized conical beam from an embedded etched fiber.

PubMed

Kalaidji, Djamel; Spajer, Michel; Marthouret, Nadège; Grosjean, Thierry

2009-06-15

We propose a method for producing a conical beam based on the lateral refraction of the TM(01) mode from a two-mode fiber after chemical etching of the cladding, and for controlling its radial polarization. The whole power of the guided mode is transferred to the refracted beam with low diffraction. Polarization control by a series of azimuthal detectors and a stress controller affords the transmission of a stabilized radial polarization through an optical fiber. A solid component usable for many applications has been obtained.

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.

Pulse Shepherding in Nonlinear Fiber Optics

NASA Technical Reports Server (NTRS)

Yeh, C.; Bergman, L.

1996-01-01

In a wavelength division multiplexed fiber system, where pulses on different wavelength beams may co-propagate in a single mode fiber, the cross-phase-modulation (CPM) effects caused by the nonlinearity of the optical fiber are unavoidable. In other words, pulses on different wavelength beams can interact with and affect each other through the intensity dependence of the refractive index of the fiber. Although CPM will not cause energy to be exchanged among the beams, the pulse shapes and locations on these beams can be altered significantly. This phenomenon makes possible the manipulation and control of pulses co-propagating on different wavelength beams through the introduction of a shepherd pulse at a separate wavelength. How this can be accomplished is demonstrated in this paper.

Role of optical computers in aeronautical control applications

NASA Technical Reports Server (NTRS)

Baumbick, R. J.

1981-01-01

The role that optical computers play in aircraft control is determined. The optical computer has the potential high speed capability required, especially for matrix/matrix operations. The optical computer also has the potential for handling nonlinear simulations in real time. They are also more compatible with fiber optic signal transmission. Optics also permit the use of passive sensors to measure process variables. No electrical energy need be supplied to the sensor. Complex interfacing between optical sensors and the optical computer is avoided if the optical sensor outputs can be directly processed by the optical computer.

Computer Sciences and Data Systems, volume 2

NASA Technical Reports Server (NTRS)

1987-01-01

Topics addressed include: data storage; information network architecture; VHSIC technology; fiber optics; laser applications; distributed processing; spaceborne optical disk controller; massively parallel processors; and advanced digital SAR processors.

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.

A Robust Distributed Multipoint Fiber Optic Gas Sensor System Based on AGC Amplifier Structure.

PubMed

Zhu, Cunguang; Wang, Rende; Tao, Xuechen; Wang, Guangwei; Wang, Pengpeng

2016-07-28

A harsh environment-oriented distributed multipoint fiber optic gas sensor system realized by automatic gain control (AGC) technology is proposed. To improve the photoelectric signal reliability, the electronic variable gain can be modified in real time by an AGC closed-loop feedback structure to compensate for optical transmission loss which is caused by the fiber bend loss or other reasons. The deviation of the system based on AGC structure is below 4.02% when photoelectric signal decays due to fiber bending loss for bending radius of 5 mm, which is 20 times lower than the ordinary differential system. In addition, the AGC circuit with the same electric parameters can keep the baseline intensity of signals in different channels of the distributed multipoint sensor system at the same level. This avoids repetitive calibrations and streamlines the installation process.

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

Sabau, Adrian S; Chen, Jian; Jones, Jonaaron F.

The increasing use of Carbon Fiber Polymer Composite (CFPC) as a lightweight material in automotive and aerospace industries requires the control of surface morphology. In this study, the composites surface was prepared by ablating the resin in the top fiber layer of the composite using an Nd:YAG laser. The CFPC specimens with T700S carbon fiber and Prepreg - T83 resin (epoxy) were supplied by Plasan Carbon Composites, Inc. as 4 ply thick, 0/90o plaques. The effect of laser fluence, scanning speed, and wavelength was investigated to remove resin without an excessive damage of the fibers. In addition, resin ablation duemore » to the power variation created by a laser interference technique is presented. Optical property measurements, optical micrographs, 3D imaging, and high-resolution optical profiler images were used to study the effect of the laser processing on the surface morphology.« less

Spatial Light Modulators as Optical Crossbar Switches

NASA Technical Reports Server (NTRS)

Juday, Richard

2003-01-01

A proposed method of implementing cross connections in an optical communication network is based on the use of a spatial light modulator (SLM) to form controlled diffraction patterns that connect inputs (light sources) and outputs (light sinks). Sources would typically include optical fibers and/or light-emitting diodes; sinks would typically include optical fibers and/or photodetectors. The sources and/or sinks could be distributed in two dimensions; that is, on planes. Alternatively or in addition, sources and/or sinks could be distributed in three dimensions -- for example, on curved surfaces or in more complex (including random) three-dimensional patterns.

Developments in fiber optics for distribution automation

NASA Technical Reports Server (NTRS)

Kirkham, H.; Friend, H.; Jackson, S.; Johnston, A.

1991-01-01

An optical fiber based communications system of unusual design is described. The system consists of a network of optical fibers overlaid on the distribution system. It is configured as a large number of interconnected rings, with some spurs. Protocols for access to and control of the network are described. Because of the way they function, the protocols are collectively called AbNET, in commemoration of the microbiologists' abbreviation Ab for antibody. Optical data links that could be optically powered are described. There are two versions, each of which has a good frequency response and minimal filtering requirements. In one, a conventional FM pulse train is used at the transmitter, and a novel form of phase-locked loop is used as demodulator. In the other, the FM transmitter is replaced with a pulse generator arranged so that the period between pulses represents the modulating signal. Transmitter and receiver designs, including temperature compensation methods, are presented. Experimental results are given.

MAFL experiment: development of photonic devices for a space-based multiaperture fiber-linked interferometer.

PubMed

Olivier, Serge; Delage, Laurent; Reynaud, Francois; Collomb, Virginie; Trouillon, Michel; Grelin, Jerome; Schanen, Isabelle; Minier, Vincent; Broquin, Jean-Emmanuel; Ruilier, Cyril; Leone, Bruno

2007-02-20

We present a three-telescope space-based interferometer prototype dedicated to high-resolution imaging. This project, named multiaperture fiber-linked interferometer (MAFL), was founded by the European Space Agency. The aim of the MAFL project is to propose, design, and implement for the first time to the best of our knowledge all the optical functions required for the global instrument on the same integrated optics (IO) component for controlling a three-arm interferometer and to obtain reliable science data. The coherent transport from telescopes to the IO component is achieved by means of highly birefringent optical fiber. The laboratory bench is presented, and the results are reported allowing us to validate the optical potentiality of the IO component in this frame. The validation measurements consist of the throughput of this optical device, the performances of metrological servoloop, and the instrumental contrasts and phase closure of the science fringes.

20 years of KVH fiber optic gyro technology: the evolution from large, low performance FOGs to compact, precise FOGs and FOG-based inertial systems

NASA Astrophysics Data System (ADS)

Napoli, Jay

2016-05-01

Precision fiber optic gyroscopes (FOGs) are critical components for an array of platforms and applications ranging from stabilization and pointing orientation of payloads and platforms to navigation and control for unmanned and autonomous systems. In addition, FOG-based inertial systems provide extremely accurate data for geo-referencing systems. Significant improvements in the performance of FOGs and FOG-based inertial systems at KVH are due, in large part, to advancements in the design and manufacture of optical fiber, as well as in manufacturing operations and signal processing. Open loop FOGs, such as those developed and manufactured by KVH Industries, offer tactical-grade performance in a robust, small package. The success of KVH FOGs and FOG-based inertial systems is due to innovations in key fields, including the development of proprietary D-shaped fiber with an elliptical core, and KVH's unique ThinFiber. KVH continually improves its FOG manufacturing processes and signal processing, which result in improved accuracies across its entire FOG product line. KVH acquired its FOG capabilities, including its patented E•Core fiber, when the company purchased Andrew Corporation's Fiber Optic Group in 1997. E•Core fiber is unique in that the light-guiding core - critical to the FOG's performance - is elliptically shaped. The elliptical core produces a fiber that has low loss and high polarization-maintaining ability. In 2010, KVH developed its ThinFiber, a 170-micron diameter fiber that retains the full performance characteristics of E•Core fiber. ThinFiber has enabled the development of very compact, high-performance open-loop FOGs, which are also used in a line of FOG-based inertial measurement units and inertial navigation systems.

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.

Next generation information communication infrastructure and case studies for future power systems

NASA Astrophysics Data System (ADS)

Qiu, Bin

As power industry enters the new century, powerful driving forces, uncertainties and new functions are compelling electric utilities to make dramatic changes in their information communication infrastructure. Expanding network services such as real time measurement and monitoring are also driving the need for more bandwidth in the communication network. These needs will grow further as new remote real-time protection and control applications become more feasible and pervasive. This dissertation addresses two main issues for the future power system information infrastructure: communication network infrastructure and associated power system applications. Optical networks no doubt will become the predominant data transmission media for next generation power system communication. The rapid development of fiber optic network technology poses new challenges in the areas of topology design, network management and real time applications. Based on advanced fiber optic technologies, an all-fiber network is investigated and proposed. The study will cover the system architecture and data exchange protocol aspects. High bandwidth, robust optical networks could provide great opportunities to the power system for better service and efficient operation. In the dissertation, different applications are investigated. One of the typical applications is the SCADA information accessing system. An Internet-based application for the substation automation system will be presented. VLSI (Very Large Scale Integration) technology is also used for one-line diagrams auto-generation. High transition rate and low latency optical network is especially suitable for power system real time control. In the dissertation, a new local area network based Load Shedding Controller (LSC) for isolated power system will be presented. By using PMU (Phasor Measurement Unit) and fiber optic network, an AGE (Area Generation Error) based accurate wide area load shedding scheme will also be proposed. The objective is to shed the load in the limited area with minimum disturbance.

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.

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.

Rare-earth-doped optical-fiber core deposition using full vapor-phase SPCVD process

NASA Astrophysics Data System (ADS)

Barnini, A.; Robin, T.; Cadier, B.; Aka, G.; Caurant, D.; Gotter, T.; Guyon, C.; Pinsard, E.; Guitton, P.; Laurent, A.; Montron, R.

2017-02-01

One key parameter in the race toward ever-higher power fiber lasers remains the rare earth doped optical core quality. Modern Large Mode Area (LMA) fibers require a fine radial control of the core refractive index (RI) close to the silica level. These low RI are achieved with multi-component materials that cannot be readily obtained using conventional solution doping based Modified Chemical Vapor Deposition (MCVD) technology. This paper presents a study of such optical material obtained through a full-vapor phase Surface Plasma Chemical Vapor Deposition (SPCVD). The SPCVD process generates straight glassy films on the inner surface of a thermally regulated synthetic silica tube under vacuum. The first part of the presented results points out the feasibility of ytterbium-doped aluminosilicate fibers by this process. In the second part we describe the challenge controlling the refractive index throughout the core diameter when using volatile fluorine to create efficient LMA fiber profiles. It has been demonstrated that it is possible to counter-act the loss of fluorine at the center of the core by adjusting the core composition locally. Our materials yielded, when used in optical fibers with numerical apertures ranging from 0.07 to 0.09, power conversion efficiency up to 76% and low background losses below 20 dB/km at 1100nm. Photodarkening has been measured to be similar to equivalent MCVD based fibers. The use of cerium as a co-dopant allowed for a complete mitigation of this laser lifetime detrimental effect. The SPCVD process enables high capacity preforms and is particularly versatile when it comes to radial tailoring of both rare earth doping level and RI. Large core diameter preforms - up to 4mm - were successfully produced.

Quantum optics. All-optical routing of single photons by a one-atom switch controlled by a single photon.

PubMed

Shomroni, Itay; Rosenblum, Serge; Lovsky, Yulia; Bechler, Orel; Guendelman, Gabriel; Dayan, Barak

2014-08-22

The prospect of quantum networks, in which quantum information is carried by single photons in photonic circuits, has long been the driving force behind the effort to achieve all-optical routing of single photons. We realized a single-photon-activated switch capable of routing a photon from any of its two inputs to any of its two outputs. Our device is based on a single atom coupled to a fiber-coupled, chip-based microresonator. A single reflected control photon toggles the switch from high reflection (R ~ 65%) to high transmission (T ~ 90%), with an average of ~1.5 control photons per switching event (~3, including linear losses). No additional control fields are required. The control and target photons are both in-fiber and practically identical, making this scheme compatible with scalable architectures for quantum information processing. Copyright © 2014, American Association for the Advancement of Science.

Coherent beam combining of collimated fiber array based on target-in-the-loop technique

NASA Astrophysics Data System (ADS)

Li, Xinyang; Geng, Chao; Zhang, Xiaojun; Rao, Changhui

2011-11-01

Coherent beam combining (CBC) of fiber array is a promising way to generate high power and high quality laser beams. Target-in-the-loop (TIL) technique might be an effective way to ensure atmosphere propagation compensation without wavefront sensors. In this paper, we present very recent research work about CBC of collimated fiber array using TIL technique at the Key Lab on Adaptive Optics (KLAO), CAS. A novel Adaptive Fiber Optics Collimator (AFOC) composed of phase-locking module and tip/tilt control module was developed. CBC experimental setup of three-element fiber array was established. Feedback control is realized using stochastic parallel gradient descent (SPGD) algorithm. The CBC based on TIL with piston and tip/tilt correction simultaneously is demonstrated. And the beam pointing to locate or sweep position of combined spot on target was achieved through TIL technique too. The goal of our work is achieve multi-element CBC for long-distance transmission in atmosphere.

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.

Real-time soil sensing based on fiber optics and spectroscopy

NASA Astrophysics Data System (ADS)

Li, Minzan

2005-08-01

Using NIR spectroscopic techniques, correlation analysis and regression analysis for soil parameter estimation was conducted with raw soil samples collected in a cornfield and a forage field. Soil parameters analyzed were soil moisture, soil organic matter, nitrate nitrogen, soil electrical conductivity and pH. Results showed that all soil parameters could be evaluated by NIR spectral reflectance. For soil moisture, a linear regression model was available at low moisture contents below 30 % db, while an exponential model can be used in a wide range of moisture content up to 100 % db. Nitrate nitrogen estimation required a multi-spectral exponential model and electrical conductivity could be evaluated by a single spectral regression. According to the result above mentioned, a real time soil sensor system based on fiber optics and spectroscopy was developed. The sensor system was composed of a soil subsoiler with four optical fiber probes, a spectrometer, and a control unit. Two optical fiber probes were used for illumination and the other two optical fiber probes for collecting soil reflectance from visible to NIR wavebands at depths around 30 cm. The spectrometer was used to obtain the spectra of reflected lights. The control unit consisted of a data logging device, a personal computer, and a pulse generator. The experiment showed that clear photo-spectral reflectance was obtained from the underground soil. The soil reflectance was equal to that obtained by the desktop spectrophotometer in laboratory tests. Using the spectral reflectance, the soil parameters, such as soil moisture, pH, EC and SOM, were evaluated.

Picometer-resolution dual-comb spectroscopy with a free-running fiber laser.

PubMed

Zhao, Xin; Hu, Guoqing; Zhao, Bofeng; Li, Cui; Pan, Yingling; Liu, Ya; Yasui, Takeshi; Zheng, Zheng

2016-09-19

Dual-comb spectroscopy holds the promise as real-time, high-resolution spectroscopy tools. However, in its conventional schemes, the stringent requirement on the coherence between two lasers requires sophisticated control systems. By replacing control electronics with an all-optical dual-comb lasing scheme, a simplified dual-comb spectroscopy scheme is demonstrated using one dual-wavelength, passively mode-locked fiber laser. Pulses with a intracavity-dispersion-determined repetition-frequency difference are shown to have good mutual coherence and stability. Capability to resolve the comb teeth and a picometer-wide optical spectral resolution are demonstrated using a simple data acquisition system. Energy-efficient, free-running fiber lasers with a small comb-tooth-spacing could enable low-cost dual-comb systems.

Fiber Optic Magnetic Field Sensors Using Metallic Glass Coatings.

NASA Astrophysics Data System (ADS)

Wang, Yu.

1990-01-01

In this thesis we have investigated the use of a magnetostrictive material with a single-mode optical fiber for detecting weak magnetic fields. The amorphous alloy Metglas^circler 2605SC (Fe_{81}B_ {13.5}Si_{3.5} C_2) was chosen as the magnetostrictive material because of the combination of its large magnetostriction and small magnetic anisotropy field among all available metals. For efficient coupling between the magnetostrictive material and the optical fiber, the magnetostrictive material was directly deposited onto the single-mode optical fiber. The coated fibers were used as the sensing element in the fiber optic magnetic field sensor (FOMS). Very high quality thick metallic glass films of the Metglas 2605 SC have been deposited using triode-magneton sputtering. This is the first time such material has been successfully deposited onto an optical fiber or onto any other substrate. The films were also deposited onto glass slides to allow the study of the magnetic properties of the film. The thicknesses of these films were 5-15 mum. The magnetic property of primary interest for our sensor application is the induced longitudinal magnetostrictive strain. However, the other magnetic properties such as magnetic anisotropy, surface and bulk coercivities, magnetic homogeneity and magnetization all affect the magnetostrictive response of the material. We have used ferromagnetic resonance (FMR) at microwave frequencies to study the magnetic anisotropy and homogeneity; vibrating sample magnetometry (VSM) to study the bulk magnetic hysteresis responses and coercivity; and the longitudinal magneto-optic kerr effect (LMOKE) to study the surface magnetic hysteresis responses and coercivity. The isothermalmagnetic annealing effect on these properties has also been studied in detail. The fiber optic magnetic field sensor constructed using the metallic-glass-coated fiber was tested. An electronic feedback control loop using a PZT cylinder was constructed for stabilizing the sensor operation. Magnetic field detection at different dither frequencies was studied in detail. The estimated minimum detectable magnetic field was about 3 times 10^{-7 } Oe. A simplified elastic model was used for the theoretical calculation of the phase shift induced in a metallic-glass -coated optical fiber with a longitudinal applied magnetic field. The phase shift as a function of coating thickness was calculated, and the experimental results at certain thicknesses were compared with the calculation. The frequency response of the FOMS was also studied in some detail. Three different configurations were used for the study of the frequency response. The results indicate that the resonances observed in the FOMS are most likely related to the mechanical resonance of the optical fiber.

High-density, microsphere-based fiber optic DNA microarrays.

PubMed

Epstein, Jason R; Leung, Amy P K; Lee, Kyong Hoon; Walt, David R

2003-05-01

A high-density fiber optic DNA microarray has been developed consisting of oligonucleotide-functionalized, 3.1-microm-diameter microspheres randomly distributed on the etched face of an imaging fiber bundle. The fiber bundles are comprised of 6000-50000 fused optical fibers and each fiber terminates with an etched well. The microwell array is capable of housing complementary-sized microspheres, each containing thousands of copies of a unique oligonucleotide probe sequence. The array fabrication process results in random microsphere placement. Determining the position of microspheres in the random array requires an optical encoding scheme. This array platform provides many advantages over other array formats. The microsphere-stock suspension concentration added to the etched fiber can be controlled to provide inherent sensor redundancy. Examining identical microspheres has a beneficial effect on the signal-to-noise ratio. As other sequences of interest are discovered, new microsphere sensing elements can be added to existing microsphere pools and new arrays can be fabricated incorporating the new sequences without altering the existing detection capabilities. These microarrays contain the smallest feature sizes (3 microm) of any DNA array, allowing interrogation of extremely small sample volumes. Reducing the feature size results in higher local target molecule concentrations, creating rapid and highly sensitive assays. The microsphere array platform is also flexible in its applications; research has included DNA-protein interaction profiles, microbial strain differentiation, and non-labeled target interrogation with molecular beacons. Fiber optic microsphere-based DNA microarrays have a simple fabrication protocol enabling their expansion into other applications, such as single cell-based assays.

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.

Local domains of motor cortical activity revealed by fiber-optic calcium recordings in behaving nonhuman primates.

PubMed

Adelsberger, Helmuth; Zainos, Antonio; Alvarez, Manuel; Romo, Ranulfo; Konnerth, Arthur

2014-01-07

Brain mapping experiments involving electrical microstimulation indicate that the primary motor cortex (M1) directly regulates muscle contraction and thereby controls specific movements. Possibly, M1 contains a small circuit "map" of the body that is formed by discrete local networks that code for specific movements. Alternatively, movements may be controlled by distributed, larger-scale overlapping circuits. Because of technical limitations, it remained unclear how movement-determining circuits are organized in M1. Here we introduce a method that allows the functional mapping of small local neuronal circuits in awake behaving nonhuman primates. For this purpose, we combined optic-fiber-based calcium recordings of neuronal activity and cortical microstimulation. The method requires targeted bulk loading of synthetic calcium indicators (e.g., OGB-1 AM) for the staining of neuronal microdomains. The tip of a thin (200 µm) optical fiber can detect the coherent activity of a small cluster of neurons, but is insensitive to the asynchronous activity of individual cells. By combining such optical recordings with microstimulation at two well-separated sites of M1, we demonstrate that local cortical activity was tightly associated with distinct and stereotypical simple movements. Increasing stimulation intensity increased both the amplitude of the movements and the level of neuronal activity. Importantly, the activity remained local, without invading the recording domain of the second optical fiber. Furthermore, there was clear response specificity at the two recording sites in a trained behavioral task. Thus, the results provide support for movement control in M1 by local neuronal clusters that are organized in discrete cortical domains.

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).

Supersymmetric Transformations in Optical Fibers

NASA Astrophysics Data System (ADS)

Macho, Andrés; Llorente, Roberto; García-Meca, Carlos

2018-01-01

Supersymmetry (SUSY) has recently emerged as a tool to design unique optical structures with degenerate spectra. Here, we study several fundamental aspects and variants of one-dimensional SUSY in axially symmetric optical media, including their basic spectral features and the conditions for degeneracy breaking. Surprisingly, we find that the SUSY degeneracy theorem is partially (totally) violated in optical systems connected by isospectral (broken) SUSY transformations due to a degradation of the paraxial approximation. In addition, we show that isospectral constructions provide a dimension-independent design control over the group delay in SUSY fibers. Moreover, we find that the studied unbroken and isospectral SUSY transformations allow us to generate refractive-index superpartners with an extremely large phase-matching bandwidth spanning the S +C +L optical bands. These singular features define a class of optical fibers with a number of potential applications. To illustrate this, we numerically demonstrate the possibility of building photonic lanterns supporting broadband heterogeneous supermodes with large effective area, a broadband all-fiber true-mode (de)multiplexer requiring no mode conversion, and different mode-filtering, mode-conversion, and pulse-shaping devices. Finally, we discuss the possibility of extrapolating our results to acoustics and quantum mechanics.

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.

In-situ Tapering of Chalcogenide Fiber for Mid-infrared Supercontinuum Generation

PubMed Central

Rudy, Charles W.; Marandi, Alireza; Vodopyanov, Konstantin L.; Byer, Robert L.

2013-01-01

Supercontinuum generation (SCG) in a tapered chalcogenide fiber is desirable for broadening mid-infrared (or mid-IR, roughly the 2-20 μm wavelength range) frequency combs1, 2 for applications such as molecular fingerprinting, 3 trace gas detection, 4 laser-driven particle acceleration, 5 and x-ray production via high harmonic generation. 6 Achieving efficient SCG in a tapered optical fiber requires precise control of the group velocity dispersion (GVD) and the temporal properties of the optical pulses at the beginning of the fiber, 7 which depend strongly on the geometry of the taper. 8 Due to variations in the tapering setup and procedure for successive SCG experiments-such as fiber length, tapering environment temperature, or power coupled into the fiber, in-situ spectral monitoring of the SCG is necessary to optimize the output spectrum for a single experiment. In-situ fiber tapering for SCG consists of coupling the pump source through the fiber to be tapered to a spectral measurement device. The fiber is then tapered while the spectral measurement signal is observed in real-time. When the signal reaches its peak, the tapering is stopped. The in-situ tapering procedure allows for generation of a stable, octave-spanning, mid-IR frequency comb from the sub harmonic of a commercially available near-IR frequency comb. 9 This method lowers cost due to the reduction in time and materials required to fabricate an optimal taper with a waist length of only 2 mm. The in-situ tapering technique can be extended to optimizing microstructured optical fiber (MOF) for SCG10 or tuning of the passband of MOFs, 11 optimizing tapered fiber pairs for fused fiber couplers12 and wavelength division multiplexers (WDMs), 13 or modifying dispersion compensation for compression or stretching of optical pulses.14-16 PMID:23748947

Influence of optical activity on rogue waves propagating in chiral optical fibers.

PubMed

Temgoua, D D Estelle; Kofane, T C

2016-06-01

We derive the nonlinear Schrödinger (NLS) equation in chiral optical fiber with right- and left-hand nonlinear polarization. We use the similarity transformation to reduce the generalized chiral NLS equation to the higher-order integrable Hirota equation. We present the first- and second-order rational solutions of the chiral NLS equation with variable and constant coefficients, based on the modified Darboux transformation method. For some specific set of parameters, the features of chiral optical rogue waves are analyzed from analytical results, showing the influence of optical activity on waves. We also generate the exact solutions of the two-component coupled nonlinear Schrödinger equations, which describe optical activity effects on the propagation of rogue waves, and their properties in linear and nonlinear coupling cases are investigated. The condition of modulation instability of the background reveals the existence of vector rogue waves and the number of stable and unstable branches. Controllability of chiral optical rogue waves is examined by numerical simulations and may bring potential applications in optical fibers and in many other physical systems.

Reconfigurable optical multiplexer based on liquid crystals for polymer optical fiber networks

NASA Astrophysics Data System (ADS)

Lallana, P. C.; Vázquez, C.; Pena, J. M. S.; Vergaz, R.

2006-12-01

In this work, different novel 3×1 multiplexer structures for being used in polymer optical fiber networks are proposed. Designs are compact, scalable, and of low consumption, capable of operating in a large wavelength range simultaneously 660, 850, and 1300 nm, due to the use of nematic liquid crystal cells. Light that comes from each input port is handled independently and eight operation modes are possible. Control electronics has been made using a programmable integrated circuit. Electronic system makes available the managing of the optical stage using a computer. An additional four optical sensors have been included for allowing the optical status checking. Finally, a polarization independent multiplexer has been implemented and tested. Insertion losses less than 4 dB and isolation better than 23 dB have been measured. In addition, 30-ms and 15-ms setup and rise times have been obtained. The proposed multiplexer can be used in any polymer optical fiber network, even in perfluorinated graded index one, and it can be specially useful in optical sensor networks, or in coarse wavelength division multiplexing networks.

Fiber-based coherent polarization beam combining with cascaded phase-locking and polarization-transforming controls

NASA Astrophysics Data System (ADS)

Yang, Yan; Geng, Chao; Li, Feng; Huang, Guan; Li, Xinyang

2018-05-01

In this paper, the fiber-based coherent polarization beam combining (CPBC) with cascaded phase-locking (PL) and polarization-transforming (PT) controls was proposed to combine imbalanced input beams where the number of the input beams is not binary, in which the PL control was performed using the piezoelectric-ring fiber-optic phase compensator, and the PT control was realized by the dynamic polarization controller, simultaneously. The principle of the proposed CPBC was introduced. The performance of the proposed CPBC was analyzed in comparison with the CPBC based on PL control and the CPBC based on PT control. The basic experiment of CPBC of three laser beams was carried out to validate the feasibility of the proposed CPBC, where cascaded controls of PL and PT were implemented based on stochastic parallel gradient descent algorithm. Simulation and experimental results show that the proposed CPBC incorporates the advantages of the two previous CPBC schemes and performs well in the closed loop. Moreover, the expansibility and the application of the proposed CPBC were validated by scaling the CPBC to combine seven laser beams. We believe that the proposed fiber-based CPBC with cascaded PL and PT controls has great potential in free space optical communications employing the multi-aperture receiver with asymmetric structure.

A Summary of the Naval Postgraduate School Research Program.

DTIC Science & Technology

1982-05-01

and testing of PCM modu- lation formats, design and test of an underwater video line using a diver’s handheld camera and bi-directional interconnection...to design and develop advanced control schemes which successfully optimize the tor- pedo steering performance for Project Courageous. cummary: Work...investigating the feasibility and design of fiber optic communications in underwater torpedo ranges. Summary: An underwater fiber optic video uplink was

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 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.

Fiber optical tweezers for microscale and nanoscale particle manipulation and force sensing

NASA Astrophysics Data System (ADS)

Liu, Yuxiang

2011-12-01

Optical tweezers have been an important tool in biology and physics for studying single molecules and colloidal systems. Most of current optical tweezers are built with microscope objectives, which are: i) expensive, ii) bulky and hard to integrate, iii) sensitive to environmental fluctuations, iv) limited in terms of working distances from the substrate, and v) rigid with the requirements on the substrate (transparent substrate made with glass and with a fixed thickness). These limitations of objective-based optical tweezers prevent them from being miniaturized. Fiber optical tweezers can provide a solution for cost reduction and miniaturization, and these optical tweezers can be potentially used in microfluidic systems. However, the existing fiber optical tweezers have the following limitations: i) low trapping efficiency due to weakly focused beams, ii) lack of the ability to control the positions of multiple particles simultaneously, and iii) limited functionalities. The overall objective of this dissertation work is to further the fundamental understanding of fiber optical tweezers through experimental study and modeling, and to develop novel fiber optical tweezers systems to enhance the capability and functionalities of fiber optical tweezers as microscale and nanoscale manipulators/sensors. The contributions of this dissertation work are summarized as follows. i) An enhanced understanding of the inclined dual-fiber optical tweezers (DFOTs) system has been achieved. Stable three dimensional (3D) optical trapping of a single micron-sized particle has been experimentally demonstrated. This is the first time that the trapping efficiency has been calibrated and the stiffness of the trap has been obtained in the experiments, which has been carried out by using two methods: the drag force method and power spectrum analysis. Such calibration enables the system to be used as a picoNewton-level force sensor in addition to a particle manipulator. The influence of system parameters on the trapping performance has been carefully investigated through both experimental and numerical studies. ii) Multiple traps have been created and carefully studied with the inclined DFOTs for the first time. Three traps, one 3D trap and two 2D traps, have been experimentally created at different vertical levels with adjustable separations and positions. iii) Multiple functionalities have been achieved and studied for the first time with the inclined DFOTs. Particle separation, grouping, stacking, rod alignment, rod rotation, and optical binding have been experimentally demonstrated. The multiple functionalities allow the inclined DFOTs to find applications in the study of interaction forces in colloidal systems as well as parallel particle manipulation in drug delivery systems. iv) Far-field superfocusing effect has been investigated and successfully demonstrated with a fiber-based surface plasmonic (SP) lens for the first time. A planar SP lens with a set of concentric nanoscale rings on a fiber endface has been developed. For the first time, a focus size that is comparable to the smallest achievable focus size of high NA objective lenses has been achieved with the fiber-based SP lens. The fiber-based SP lens can bridge the nanoscale particles/systems and the macroscale power sources/detectors, which has been a long standing challenge for nanophotonics. In addition to optical trapping, the fiber-based SP lens will impact many applications including high-resolution lithography, high-resolution fluorescence detection, and sub-wavelength imaging. v) Trapping ability enhanced with the fiber-based SP lens has been successfully demonstrated. With the help of the fiber-based SP lens, the trapping efficiency of fiber optical tweezers has been significantly enhanced, which is comparable with that of objective-based optical tweezers. A submicron-sized bacterium has been successfully trapped in three dimensions for the first time with optical tweezers based on single fibers.

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

High-Speed Interrogation for Large-Scale Fiber Bragg Grating Sensing

PubMed Central

Hu, Chenyuan; Bai, Wei

2018-01-01

A high-speed interrogation scheme for large-scale fiber Bragg grating (FBG) sensing arrays is presented. This technique employs parallel computing and pipeline control to modulate incident light and demodulate the reflected sensing signal. One Electro-optic modulator (EOM) and one semiconductor optical amplifier (SOA) were used to generate a phase delay to filter reflected spectrum form multiple candidate FBGs with the same optical path difference (OPD). Experimental results showed that the fastest interrogation delay time for the proposed method was only about 27.2 us for a single FBG interrogation, and the system scanning period was only limited by the optical transmission delay in the sensing fiber owing to the multiple simultaneous central wavelength calculations. Furthermore, the proposed FPGA-based technique had a verified FBG wavelength demodulation stability of ±1 pm without average processing. PMID:29495263

High-Speed Interrogation for Large-Scale Fiber Bragg Grating Sensing.

PubMed

Hu, Chenyuan; Bai, Wei

2018-02-24

A high-speed interrogation scheme for large-scale fiber Bragg grating (FBG) sensing arrays is presented. This technique employs parallel computing and pipeline control to modulate incident light and demodulate the reflected sensing signal. One Electro-optic modulator (EOM) and one semiconductor optical amplifier (SOA) were used to generate a phase delay to filter reflected spectrum form multiple candidate FBGs with the same optical path difference (OPD). Experimental results showed that the fastest interrogation delay time for the proposed method was only about 27.2 us for a single FBG interrogation, and the system scanning period was only limited by the optical transmission delay in the sensing fiber owing to the multiple simultaneous central wavelength calculations. Furthermore, the proposed FPGA-based technique had a verified FBG wavelength demodulation stability of ±1 pm without average processing.

Lens-free all-fiber probe with an optimized output beam for optical coherence tomography.

PubMed

Ding, Zhihua; Qiu, Jianrong; Shen, Yi; Chen, Zhiyan; Bao, Wen

2017-07-15

A high-efficiency lensless all-fiber probe for optical coherence tomography (OCT) is presented. The probe is composed of a segment of large-core multimode fiber (MMF), a segment of tapered MMF, and a length of single-mode fiber (SMF). A controllable output beam can be designed by a simple adjustment of its probe structure parameters (PSPs), instead of the selection of fibers with different optical parameters. A side-view probe with a diameter of 340 μm and a rigid length of 6.37 mm was fabricated, which provides an effective imaging range of ∼0.6  mm with a full width at half-maximum beam diameter of less than 30 μm. The insertion loss of the probe was measured to be 0.81 dB, ensuring a high sensitivity of 102.25 dB. Satisfactory images were obtained by the probe-based OCT system, demonstrating the feasibility of the probe for endoscopic OCT applications.

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).

High brightness photonic lantern kW-class amplifier

NASA Astrophysics Data System (ADS)

Montoya, Juan; Hwang, Chris; Aleshire, Chris; Reed, Patricia; Martz, Dale; Riley, Mike; Trainor, Michael; Belley, Catherine; Shaw, Scot; Fan, T. Y.; Ripin, Dan

2018-02-01

Pump-limited kW-class operation in a multimode fiber amplifier using adaptive mode control was achieved. A photonic lantern front end was used to inject an arbitrary superposition of modes on the input to a kW-class fiber amplifier to achieve a nearly diffraction-limited output. We report on the adaptive spatial mode control architecture which allows for compensating transverse-mode disturbances at high power. We also describe the advantages of adaptive spatial mode control for optical phased array systems. In particular, we show that the additional degrees of freedom allow for broader steering and improved atmospheric turbulence compensation relative to piston-only optical phased arrays.

Wavelength tunable ultrafast fiber laser via reflective mirror with taper structure.

PubMed

Fang, Li; Huang, Chuyun; Liu, Ting; Gogneau, Noelle; Bourhis, Eric; Gierak, Jacques; Oudar, Jean-Louis

2016-12-20

Laser sources with a controllable flexible wavelength have found widespread applications in optical fiber communication, optical sensing, and microscopy. Here, we report a tunable mode-locked fiber laser using a graphene-based saturable absorber and a tapered mirror as an end mirror in the cavity. The phase layer in the mirror is precisely etched by focused ion beam (FIB) milling technology, and the resonant wavelength of the mirror shifts correspond to the different etch depths. By scanning the tapered mirror mechanically, the center wavelength of a mode-locked fiber laser can be continuously tuned from 1562 to 1532 nm, with a pulse width in the sub-ps level and repetition rate of 27 MHz.

Color tunable photonic textiles for wearable display applications

NASA Astrophysics Data System (ADS)

Sayed, I.; Berzowska, J.; Skorobogatiy, M.

2010-04-01

Integration of optical functionalities such as light emission, processing and collection into flexible woven matrices of fabric have grabbed a lot of attention in the last few years. Photonic textiles frequently involve optical fibers as they can be easily processed together with supporting fabric fibers. This technology finds uses in various fields of application such as interactive clothing, signage, wearable health monitoring sensors and mechanical strain and deformation detectors. Recent development in the field of Photonic Band Gap optical fibers (PBG) could potentially lead to novel photonic textiles applications and techniques. Particularly, plastic PBG Bragg fibers fabricated in our group have strong potential in the field of photonic textiles as they offer many advantages over standard silica fibers at the same low cost. Among many unusual properties of PBG textiles we mention that they are highly reflective, PBG textiles are colored without using any colorants, PBG textiles can change their color by controlling the relative intensities of guided and reflected light, and finally, PBG textiles can change their colors when stretched. Some of the many experimental realization of photonic bandgap fiber textiles and their potential applications in wearable displays are discussed.

Repetition rate multiplication of frequency comb using all-pass fiber resonator

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

Yang, Lijun; Yang, Honglei; Zhang, Hongyuan

2016-09-15

We propose a stable method for repetition rate multiplication of a 250-MHz Er-fiber frequency comb by a phase-locked all-pass fiber ring resonator, whose phase-locking configuration is simple. The optical path length of the fiber ring resonator is automatically controlled to be accurately an odd multiple of half of the original cavity length using an electronical phase-locking unit with an optical delay line. As for shorter cavity length of the comb, high-order odd multiple is preferable. Because the power loss depends only on the net-attenuation of the fiber ring resonator, the energetic efficiency of the proposed method is high. The inputmore » and output optical spectrums show that the spectral width of the frequency comb is clearly preserved. Besides, experimental results show less pulse intensity fluctuation and 35 dB suppression ratio of side-modes while providing a good long-term and short-term frequency stability. Higher-order repetition rate multiplication to several GHz can be obtained by using several fiber ring resonators in cascade configuration.« less

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.

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.

Comparative study of 2-DOF micromirrors for precision light manipulation

NASA Astrophysics Data System (ADS)

Young, Johanna I.; Shkel, Andrei M.

2001-08-01

Many industry experts predict that the future of fiber optic telecommunications depends on the development of all-optical components for switching of photonic signals from fiber to fiber throughout the networks. MEMS is a promising technology for providing all-optical switching at high speeds with significant cost reductions. This paper reports on the the analysis of two designs for 2-DOF electrostatically actuated MEMS micromirrors for precision controllable large optical switching arrays. The behavior of the micromirror designs is predicted by coupled-field electrostatic and modal analysis using a finite element analysis (FEA) multi-physics modeling software. The analysis indicates that the commonly used gimbal type mirror design experiences electrostatic interference and would therefore be difficult to precisely control for 2-DOF motion. We propose a new design approach which preserves 2-DOF actuation while minimizing electrostatic interference between the drive electrodes and the mirror. Instead of using two torsional axes, we use one actuator which combines torsional and flexural DOFs. A comparative analysis of the conventional gimbal design and the one proposed in this paper is performed.

EC93-42065-6

NASA Image and Video Library

1993-07-12

The National Aeronautics and Space Administration's Systems Research Aircraft (SRA), a highly modified F-18 jet fighter, on an early research flight over Rogers Dry Lake. The former Navy aircraft was flown by NASA's Dryden Flight Research Center at Edwards Air Force Base, California, to evaluate a number of experimental aerospace technologies in a multi-year, joint NASA/DOD/industry program. Among the more than 20 experiments flight-tested were several involving fiber optic sensor systems. Experiments developed by McDonnell-Douglas and Lockheed-Martin centered on installation and maintenace techniques for various types of fiber-optic hardware proposed for use in military and commercial aircraft, while a Parker-Hannifin experiment focused on alternative fiber-optic designs for postion measurement sensors as well as operational experience in handling optical sensor systems. Other experiments flown on this testbed aircraft included electronically-controlled control surface actuators, flush air data collection systems, "smart" skin antennae and laser-based systems. Incorporation of one or more of these technologies in future aircraft and spacecraft could result in signifigant savings in weight, maintenance and overall cost.

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.

Polymer optical fiber tapering using hot water

NASA Astrophysics Data System (ADS)

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

2017-06-01

We perform a pilot trial of highly convenient taper fabrication for polymer optical fibers (POFs) using hot water. A ∼380-mm-long POF taper is successfully fabricated, and its ∼150-mm-long waist has a uniform outer diameter of ∼230 µm. The shape is in good agreement with the theoretical prediction. The optical loss dependence on the strain applied to the waist shows an interesting behavior exhibiting three regimes, the origins of which are inferred by microscopic observations. We then discuss the controllability of the taper length.

Optical-Fiber Power Meter Comparison between NIST and KRISS.

PubMed

Vayshenker, I; Kim, S K; Hong, K; Lee, D-H; Livigni, D J; Li, X; Lehman, J H

2012-01-01

We describe the results of a comparison of reference standards between the National Institute of Standards and Technology (NIST-USA) and Korea Research Institute of Standards and Science (KRISS-R.O. Korea) for optical fiber-based power measurements at wavelengths of 1302 nm and 1546 nm. We compare the laboratories' reference standards by means of a temperature-controlled optical trap detector. Measurement results showed the largest difference of less than 2.5 parts in 10(3), which is within the combined standard (k=1) uncertainty for the two laboratories' reference standards.

Optical-Fiber Power Meter Comparison Between NIST and PTB.

PubMed

Vayshenker, I; Haars, H; Li, X; Lehman, J H; Livigni, D J

2003-01-01

We describe the results of a comparison of reference standards between the National Institute of Standards and Technology (NIST-USA) and Physikalisch-Technische Bundesanstalt (PTB-Germany) at nominal wavelengths of 1300 nm and 1550 nm using an optical-fiber cable. Both laboratories used thermal detectors as reference standards. A novel temperature-controlled, optical-trap detector was used as a transfer standard to compare two reference standards. Measurement results showed differences of less than 1.5 × 10(-3), which is within the combined uncertainty for both laboratories.

Cost-effective optical switch matrix for microwave phased-array

NASA Technical Reports Server (NTRS)

Pan, J. J.; Chia, S. L.; Li, W. Z.; Grove, C. H.

1991-01-01

An all-fiber (6x6) optical shutter switch matrix with the control system for microwave phased array has been demonstrated. The device offers the advantages of integrated configuration, low cost, low power consumption, small size, and light weight. The maximum extinction ratio (among 36 individual pixel) of this switch matrix at 840 nm is 24.2 dB, and the switching time is less than 120 microsec. In addition to phased array application, this low cost switch matrix is extremely attractive for fiber optic switching networks.

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.

Fiber optic systems for colorimetry and scattered colorimetry

NASA Astrophysics Data System (ADS)

Mignani, Anna G.; Mencaglia, Andrea A.; Ciaccheri, Leonardo

2005-09-01

An innovative series of optical fiber sensors based on spectroscopic interrogation is presented. The sensors are custom-designed for a wide range of applications, including gasoline colorimetry, chromium monitoring of sewage, museum lighting control, for use with a platform for interrogating an array of absorption-based chemical sensors, as well as for color and turbidity measurements. Two types of custom-design instrumentation have been developed, both making use of LED light sources and a low-cost optical fiber spectrometer to perform broadband spectral measurements in the visible spectral range. The first was designed especially to address color-based sensors, while the second assessed the combined color and turbidity of edible liquids such as olive oil. Both are potentially exploitable in other industrial and environmental applications.

Dual frequency comb metrology with one fiber laser

NASA Astrophysics Data System (ADS)

Zhao, Xin; Takeshi, Yasui; Zheng, Zheng

2016-11-01

Optical metrology techniques based on dual optical frequency combs have emerged as a hotly studied area targeting a wide range of applications from optical spectroscopy to microwave and terahertz frequency measurement. Generating two sets of high-quality comb lines with slightly different comb-tooth spacings with high mutual coherence and stability is the key to most of the dual-comb schemes. The complexity and costs of such laser sources and the associated control systems to lock the two frequency combs hinder the wider adoption of such techniques. Here we demonstrate a very simple and rather different approach to tackle such a challenge. By employing novel laser cavity designs in a mode-locked fiber laser, a simple fiber laser setup could emit dual-comb pulse output with high stability and good coherence between the pulse trains. Based on such lasers, comb-tooth-resolved dual-comb optical spectroscopy is demonstrated. Picometer spectral resolving capability could be realized with a fiber-optic setup and a low-cost data acquisition system and standard algorithms. Besides, the frequency of microwave signals over a large range can be determined based on a simple setup. Our results show the capability of such single-fiber-laser-based dual-comb scheme to reduce the complexity and cost of dual-comb systems with excellent quality for different dual-comb applications.

Few-Nucleon Charge Radii and a Precision Isotope Shift Measurement in Helium

NASA Astrophysics Data System (ADS)

Hassan Rezaeian, Nima; Shiner, David

2015-05-01

Precision atomic theory and experiment provide a valuable method to determine few nucleon charge radii, complementing the more direct scattering approaches, and providing sensitive tests of few-body nuclear theory. Some puzzles with respect to this method exist, particularly in the muonic and electronic measurements of the proton radius, and as well with respect to measurements of nuclear size in helium. We perform precision measurements of the isotope shift of the 23S -23P transitions in 3He and 4He. A tunable laser frequency discriminator and electro-optic modulation technique give precise frequency and intensity control. We select (ts <50 ms) and stabilize the intensity of the required sideband and eliminate the unused sidebands (<= 10¬5) . The technique uses a MEMS fiber switch (ts = 10 ms) and several temperature stabilized narrow band (3 GHz) fiber gratings. A fiber based optical circulator and amplifier provide the desired isolation and net gain for the selected frequency. A beam with both species of helium is achieved using a custom fiber laser for simultaneous optical pumping. A servo-controlled retro-reflected laser beam eliminates Doppler effects. Careful detection design and software control allows for unbiased data collection. Current results will be discussed. This work is supported by NSF PHY-1068868 and PHY-1404498.

Progress in holographic applications; Proceedings of the Meeting, Cannes, France, December 5, 6, 1985

NASA Technical Reports Server (NTRS)

Ebbeni, Jean (Editor)

1986-01-01

Papers are presented on a holographic recording material containing poly-n-vinylcarbozole, photoelectrochemical etching of holographic gratings in semiconductors, the analysis and construction of powered reflection holographic optical elements, achromatic display holograms in dichromated gelatin, and image blurring in display holograms and in holographic optical elements. Topics discussed include two-dimensional optical beam switching techniques using dynamnic holography, a new holographic interferometer with monomode fibers for integrated optics applications, computer controlled holography, and the copying of holograms using incoherent light. Consideration is given to holography of very far objects, rainbow holography with a multimode laser source, and the use of an endoscope for optical fiber holography.

Slowdown of group velocity of light in dual-frequency laser-pumped cascade structure of Er3+-doped optical fiber at room temperature

NASA Astrophysics Data System (ADS)

Qiu, Wei; Yang, Yujing; Gao, Yuan; Liu, Jianjun; Lv, Pin; Jiang, Qiuli

2018-04-01

Slow light is demonstrated in the cascade structure of an erbium-doped fiber with two forward propagation pumps. The results of the numerical simulation of the time delay and the optimum modulation frequency complement each other. The time delay and the optimum modulation frequency depend on the pump ratio G (G  =  {{P}1480}:{{P}980} ). The discussion results of this paper show that a larger time delay of slow light propagation can be obtained in the cascade structure of Er3+-doped optical fibers with dual-frequency laser pumping. Compared to previous research methods, the dual-frequency laser-pumped cascade structure of an Er3+-doped optical fiber is more controllable. Based on our discussion the pump ratio G should be selected in order to obtain a more appropriate time delay and the slowdown of group velocity.

Modal demultiplexing properties of tapered and nanostructured optical fibers for in vivo optogenetic control of neural activity.

PubMed

Pisanello, Marco; Della Patria, Andrea; Sileo, Leonardo; Sabatini, Bernardo L; De Vittorio, Massimo; Pisanello, Ferruccio

2015-10-01

Optogenetic approaches to manipulate neural activity have revolutionized the ability of neuroscientists to uncover the functional connectivity underlying brain function. At the same time, the increasing complexity of in vivo optogenetic experiments has increased the demand for new techniques to precisely deliver light into the brain, in particular to illuminate selected portions of the neural tissue. Tapered and nanopatterned gold-coated optical fibers were recently proposed as minimally invasive multipoint light delivery devices, allowing for site-selective optogenetic stimulation in the mammalian brain [Pisanello , Neuron82, 1245 (2014)]. Here we demonstrate that the working principle behind these devices is based on the mode-selective photonic properties of the fiber taper. Using analytical and ray tracing models we model the finite conductance of the metal coating, and show that single or multiple optical windows located at specific taper sections can outcouple only specific subsets of guided modes injected into the 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.

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.

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.

Investigating the Strain, Temperature and Humidity Sensitivity of a Multimode Graded-Index Perfluorinated Polymer Optical Fiber with Bragg Grating

PubMed Central

Zheng, Yulong; Bremer, Kort

2018-01-01

In this work we investigate the strain, temperature and humidity sensitivity of a Fiber Bragg Grating (FBG) inscribed in a near infrared low-loss multimode perfluorinated polymer optical fiber based on cyclic transparent optical polymer (CYTOP). For this purpose, FBGs were inscribed into the multimode CYTOP fiber with a core diameter of 50 µm by using a krypton fluoride (KrF) excimer laser and the phase mask method. The evolution of the reflection spectrum of the FBG detected with a multimode interrogation technique revealed a single reflection peak with a full width at half maximum (FHWM) bandwidth of about 9 nm. Furthermore, the spectral envelope of the single FBG reflection peak can be optimized depending on the KrF excimer laser irradiation time. A linear shift of the Bragg wavelength due to applied strain, temperature and humidity was measured. Furthermore, depending on irradiation time of the KrF excimer laser, both the failure strain and strain sensitivity of the multimode fiber with FBG can be controlled. The inherent low light attenuation in the near infrared wavelength range (telecommunication window) of the multimode CYTOP fiber and the single FBG reflection peak when applying the multimode interrogation set-up will allow for new applications in the area of telecommunication and optical sensing. PMID:29734734

Investigating the Strain, Temperature and Humidity Sensitivity of a Multimode Graded-Index Perfluorinated Polymer Optical Fiber with Bragg Grating.

PubMed

Zheng, Yulong; Bremer, Kort; Roth, Bernhard

2018-05-05

In this work we investigate the strain, temperature and humidity sensitivity of a Fiber Bragg Grating (FBG) inscribed in a near infrared low-loss multimode perfluorinated polymer optical fiber based on cyclic transparent optical polymer (CYTOP). For this purpose, FBGs were inscribed into the multimode CYTOP fiber with a core diameter of 50 µm by using a krypton fluoride (KrF) excimer laser and the phase mask method. The evolution of the reflection spectrum of the FBG detected with a multimode interrogation technique revealed a single reflection peak with a full width at half maximum (FHWM) bandwidth of about 9 nm. Furthermore, the spectral envelope of the single FBG reflection peak can be optimized depending on the KrF excimer laser irradiation time. A linear shift of the Bragg wavelength due to applied strain, temperature and humidity was measured. Furthermore, depending on irradiation time of the KrF excimer laser, both the failure strain and strain sensitivity of the multimode fiber with FBG can be controlled. The inherent low light attenuation in the near infrared wavelength range (telecommunication window) of the multimode CYTOP fiber and the single FBG reflection peak when applying the multimode interrogation set-up will allow for new applications in the area of telecommunication and optical sensing.

Bubble-on-fiber (BoF): a built-in tunable broadband acousto-optic sensor for liquid-immersible in situ measurements.

PubMed

Xu, Hongsong; Wang, Guanyu; Ma, Jun; Jin, Long; Oh, Kyunghwan; Guan, Bai-Ou

2018-04-30

A new type of tunable broadband fiber-optic acousto-optic sensor was experimentally demonstrated by utilizing a bubble-on-fiber (BoF) interferometer. A single micro-bubble was generated by injecting a heating laser at λ = 980 nm on the metalized facet of an optical fiber. The BoF formed a spherical micro-cavity in water whose acoustic deformation was precisely detected by using a narrowband DFB laser at 1550 nm. The heating light and the interrogating light were fed into a single fiber probe by wavelength division multiplexing (WDM) realizing a small footprint all-fiber configuration. The diameter of the BoF was stabilized with a variation less than 0.5 nm by fast servo-control of the heating laser power. The stabilized BoF served as a Fabry-Pérot cavity that can be deformed by acoustic perturbation, and a minimum detectable pressure level of as low as ~1 mPa/Hz 1/2 was achieved in a frequency range of over 60 kHz in water at room temperature. Our proposed BoF technology can provide a tunable, flexible and all-fiber solution to detect minute acoustically driven perturbations combining high-precision interferometry. Due to the very small form-factor, the technique can find applications of liquid-immersible in situ measurements in bio-molecular/cell detection and biochemical phenomena study.

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.

In-Situ Cure Monitoring of the Immidization Reaction of PMR-15

NASA Technical Reports Server (NTRS)

Cossins, Sheryl; Kellar, Jon J.; Winter, Robb M.

1997-01-01

Glass fiber reinforced polymer composites are becoming widely used in industry. With this increase in production, an in-situ method of quality control for the curing of the polymer is desirable. This would allow for the production of high-quality parts having more uniform properties.' Recently, in-situ fiber optic monitoring of polymer curing has primarily focused on epoxy resins and has been performed by Raman or fluorescence methods. In addition, some infrared (IR) investigations have been performed using transmission or ATR cells. An alternate IR approach involves using optical fibers as a sensor by utilizing evanescent wave spectroscopy.

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.

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

Micromachined fiber optic Fabry-Perot underwater acoustic probe

NASA Astrophysics Data System (ADS)

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

2014-08-01

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

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.

Fiber Optic Control System integration for advanced aircraft. Electro-optic and sensor fabrication, integration, and environmental testing for flight control systems

NASA Technical Reports Server (NTRS)

Seal, Daniel W.; Weaver, Thomas L.; Kessler, Bradley L.; Bedoya, Carlos A.; Mattes, Robert E.

1994-01-01

This report describes the design, development, and testing of passive fiber optic sensors and a multiplexing electro-optic architecture (EOA) for installation and flight test on a NASA-owned F-18 aircraft. This hardware was developed under the Fiber Optic Control Systems for Advanced Aircraft program, part of a multiyear NASA initiative to design, develop, and demonstrate through flight test 'fly-by-light' systems for application to advanced aircraft flight and propulsion control. This development included the design and production of 10 passive optical sensors and associated multiplexed EOA hardware based on wavelength division multiplexed (WDM) technology. A variety of sensor types (rotary position, linear position, temperature, and pressure) incorporating a broad range of sensor technologies (WDM analog, WDM digital, analog microbend, and fluorescent time rate of decay) were obtained from different manufacturers and functionally integrated with an independently designed EOA. The sensors were built for installation in a variety of aircraft locations, placing the sensors in a variety of harsh environments. The sensors and EOA were designed and built to have the resulting devices be as close as practical to a production system. The integrated system was delivered to NASA for flight testing on a NASA-owned F-18 aircraft. Development and integration testing of the system provided valuable information as to which sensor types were simplest to design and build for a military aircraft environment and which types were simplest to operate with a multiplexed EOA. Not all sensor types met the full range of performance and environmental requirements. EOA development problems provided information on directions to pursue in future fly-by-light flight control development programs. Lessons learned in the development of the EOA and sensor hardware are summarized.

Fiber Optic Control System integration for advanced aircraft. Electro-optic and sensor fabrication, integration, and environmental testing for flight control systems

NASA Astrophysics Data System (ADS)

Seal, Daniel W.; Weaver, Thomas L.; Kessler, Bradley L.; Bedoya, Carlos A.; Mattes, Robert E.

1994-11-01

This report describes the design, development, and testing of passive fiber optic sensors and a multiplexing electro-optic architecture (EOA) for installation and flight test on a NASA-owned F-18 aircraft. This hardware was developed under the Fiber Optic Control Systems for Advanced Aircraft program, part of a multiyear NASA initiative to design, develop, and demonstrate through flight test 'fly-by-light' systems for application to advanced aircraft flight and propulsion control. This development included the design and production of 10 passive optical sensors and associated multiplexed EOA hardware based on wavelength division multiplexed (WDM) technology. A variety of sensor types (rotary position, linear position, temperature, and pressure) incorporating a broad range of sensor technologies (WDM analog, WDM digital, analog microbend, and fluorescent time rate of decay) were obtained from different manufacturers and functionally integrated with an independently designed EOA. The sensors were built for installation in a variety of aircraft locations, placing the sensors in a variety of harsh environments. The sensors and EOA were designed and built to have the resulting devices be as close as practical to a production system. The integrated system was delivered to NASA for flight testing on a NASA-owned F-18 aircraft. Development and integration testing of the system provided valuable information as to which sensor types were simplest to design and build for a military aircraft environment and which types were simplest to operate with a multiplexed EOA. Not all sensor types met the full range of performance and environmental requirements. EOA development problems provided information on directions to pursue in future fly-by-light flight control development programs. Lessons learned in the development of the EOA and sensor hardware are summarized.

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.

Multimaterial Acoustic Fibers

NASA Astrophysics Data System (ADS)

Chocat, Noemie

The emergence of multimaterial fibers that combine a multiplicity of solid materials with disparate electrical, optical, and mechanical properties into a single fiber presents new opportunities for extending fiber applications well beyond optical transmission. Fiber reflectors, thermal detectors, photodetectors, chemical sensors, surface-emitting fiber lasers, fiber diodes, and other functional fiber devices have been demonstrated with this approach. Yet, throughout this development and indeed the development of fibers in general, a key premise has remained unchanged : that fibers are essentially static devices incapable of controllably changing their properties at high frequencies. Unique opportunities would arise if a rapid, electrically-driven mechanism for changing fiber properties existed. A wide spectrum of hitherto passive fiber devices could at once become active with applications spanning electronics, mechanics, acoustics, and optics, with the benefits of large surface-area, structural robustness, and mechanical flexibility. This thesis addresses the challenges and opportunities associated with the realization of electromechanical transduction in fibers through the integration of internal piezoelectric and electrostrictive domains. The fundamental challenges related to the fabrication of piezoelectric devices in fiber form are analyzed from a materials perspective, and candidate materials and geometries are selected that are compatible with the thermal drawing process. The first realization of a thermally drawn piezoelectric fiber device is reported and its piezoelectric response is established over a wide range of frequencies. The acoustic properties of piezoelectric fiber devices are characterized and related to their mechanical and geometric properties. Collective effects in multi-fiber constructs are discussed and demonstrated by the realization of a linear phased array of piezoelectric fibers capable of acoustic beam steering. High strain actuation capabilities in a fiber are demonstrated based on the integration of a highly electrostrictive relaxor ferroelectric polymer. The potential of this approach to realize integrated microelectromechanical systems in fibers is illustrated by the fabrication of a hybrid fiber comprising an electrostrictive device and an adjacent Fabry-Perot optical filter. Amplitude modulation of the light reflected from the Fabry-Perot cavity is demonstrated through electric field induced tuning of the cavity resonance. (Copies available exclusively from MIT Libraries, libraries.mit.edu/docs - docs@mit.edu)

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.

Use of a reflective semiconductor optical amplifier and dual-ring architecture design to produce a stable multi-wavelength fiber laser

NASA Astrophysics Data System (ADS)

Yeh, Chien-Hung; Chow, Chi-Wai; Lu, Shao-Sheng

2014-05-01

In this work, we propose and demonstrate a multi-wavelength laser source produced by utilizing a C-band reflective semiconductor optical amplifier (RSOA) with a dual-ring fiber cavity. Here, the laser cavity consists of an RSOA, a 1 × 2 optical coupler, a 2 × 2 optical coupler and a polarization controller. As a result, thirteen to eighteen wavelengths around the L band could be generated simultaneously when the bias current of the C-band RSOA was driven at 30-70 mA. In addition, the output stabilities of the power and wavelength are also discussed.

Fiber optic temperature sensor gives rise to thermal analysis in complex product design

NASA Astrophysics Data System (ADS)

Cheng, Andrew Y. S.; Pau, Michael C. Y.

1996-09-01

A computer-adapted fiber-optic temperature sensing system has been developed which aims to study both the theoretical aspect of fiber temperature sensing and the experimental aspect of such system. The system consists of a laser source, a fiber sensing element, an electronic fringes counting device, and an on-line personal computer. The temperature measurement is achieved by the conventional double beam fringe counting method with optical path length changes in the sensing beam due to the fiber expansion. The system can automatically measure the temperature changes in a sensing fiber arm which provides an insight of the heat generation and dissipation of the measured system. Unlike the conventional measuring devices such as thermocouples or solid state temperature sensors, the fiber sensor can easily be wrapped and shaped to fit the surface of the measuring object or even inside a molded plastic parts such as a computer case, which gives much more flexibility and applicability to the analysis of heat generation and dissipation in the operation of these machine parts. The reference beam is being set up on a temperature controlled optical bench to facilitate high sensitivity and high temperature resolution. The measuring beam has a motorized beam selection device for multiple fiber beam measurement. The project has been demonstrated in the laboratory and the system sensitivity and resolution are found to be as high as 0.01 degree Celsius. It is expected the system will find its application in many design studies which require thermal budgeting.

Tapered optical fiber tip probes based on focused ion beam-milled Fabry-Perot microcavities

NASA Astrophysics Data System (ADS)

André, Ricardo M.; Warren-Smith, Stephen C.; Becker, Martin; Dellith, Jan; Rothhardt, Manfred; Zibaii, M. I.; Latifi, H.; Marques, Manuel B.; Bartelt, Hartmut; Frazão, Orlando

2016-09-01

Focused ion beam technology is combined with dynamic chemical etching to create microcavities in tapered optical fiber tips, resulting in fiber probes for temperature and refractive index sensing. Dynamic chemical etching uses hydrofluoric acid and a syringe pump to etch standard optical fibers into cone structures called tapered fiber tips where the length, shape, and cone angle can be precisely controlled. On these tips, focused ion beam is used to mill several different types of Fabry-Perot microcavities. Two main cavity types are initially compared and then combined to form a third, complex cavity structure. In the first case, a gap is milled on the tapered fiber tip which allows the external medium to penetrate the light guiding region and thus presents sensitivity to external refractive index changes. In the second, two slots that function as mirrors are milled on the tip creating a silica cavity that is only sensitive to temperature changes. Finally, both cavities are combined on a single tapered fiber tip, resulting in a multi-cavity structure capable of discriminating between temperature and refractive index variations. This dual characterization is performed with the aid of a fast Fourier transform method to separate the contributions of each cavity and thus of temperature and refractive index. Ultimately, a tapered optical fiber tip probe with sub-standard dimensions containing a multi-cavity structure is projected, fabricated, characterized and applied as a sensing element for simultaneous temperature and refractive index discrimination.

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.

New Methods for Rotation Sensing by Using a Two-Coupler Fiber-Optic Ring Resonator

NASA Astrophysics Data System (ADS)

Seraji, Faramarz E.

1993-04-01

This paper presents a theoretical analysis of new methods for rotation sensing by using a two-coupler type fiber-optic ring resonator. It is shown that in the proposed methods a resonance spike can be generated whose amplitude gives a direct measure of the rotation rates. The approaches are simple and have a major advantage of not using a closed-loop to control the operating points for resonance.

A Fiber Optic Beam Controller for Phased Array Radars.

DTIC Science & Technology

1982-06-01

characteristics with limited discussion of the underlying physics . The components which will be surveyed are: ( 1 ) Optical Fibers, (2) Light Emitters, (3...effect rather than by a physical grating. The defining equation is An = 1 /2 n3 ps p = photo-elastic constant (21) s = the acoustic strain amplitude...RESULTS AND AN INTUITIVE MODEL OF NEAR TERM TECHNOLOGY CHANGES The experimental results are combined with other data and the conclusions drawn are: ( 1

Ternary liquid scintillator for optical fiber applications

DOEpatents

Franks, Larry A.; Lutz, Stephen S.

1982-01-01

A multicomponent liquid scintillator solution for use as a radiation-to-light converter in conjunction with a fiber optic transmission system. The scintillator includes a quantity of 5-amino-9-diethylaminobenz (a) phenoxazonium nitrate (Nile Blue Nitrate) as a solute in a fluor solvent such as benzyl alcohol. The use of PPD as an additional solute is also disclosed. The system is controllable by addition of a suitable quenching agent, such as phenol.

Optical imaging of tumor cells in hollow fibers: evaluation of the antitumor activities of anticancer drugs and target validation.

PubMed

Zhang, Guo-Jun; Chen, Tsing-Bau; Bednar, Bohumil; Connolly, Brett M; Hargreaves, Richard; Sur, Cyrille; Williams, David L

2007-08-01

The in vivo hollow fiber assay, in which semipermeable hollow fibers filled with tumor cells, are implanted into animals, was originally developed to screen for anticancer compounds before assessment in more complex tumor models. To enhance screening and evaluation of anticancer drugs, we have applied optical imaging technology to this assay. To demonstrate that tumor cells inside hollow fibers can communicate with the host mice, we have used fluorescence imaging in vivo and CD31 immunostaining ex vivo to show that angiogenesis occurs around cell-filled hollow fibers by 2 weeks after subcutaneous implantation. Bioluminescence imaging has been used to follow the number of luciferase-expressing tumor cells within implanted hollow fibers; proliferation of those cells was found to be significantly inhibited by docetaxel or irinotecan. We also used bioluminescence imaging of hollow fibers to monitor the nuclear factor kappaB (NFkappaB) pathway in vivo; NFkappaB activation by lipopolysaccharide and tumor necrosis factor-alpha was evaluated in tumor cell lines genetically engineered to express luciferase controlled by an NFkappaB-responsive element. These results demonstrate that optical imaging of hollow fibers containing reporter tumor cells can be used for the rapid and accurate evaluation of antitumor activities of anticancer drugs and for measurement of molecular pathways.

Design of a Multicast Optical Packet Switch Based on Fiber Bragg Grating Technology for Future Networks

NASA Astrophysics Data System (ADS)

Cheng, Yuh-Jiuh; Yeh, Tzuoh-Chyau; Cheng, Shyr-Yuan

2011-09-01

In this paper, a non-blocking multicast optical packet switch based on fiber Bragg grating technology with optical output buffers is proposed. Only the header of optical packets is converted to electronic signals to control the fiber Bragg grating array of input ports and the packet payloads should be transparently destined to their output ports so that the proposed switch can reduce electronic interfaces as well as the bit rate. The modulation and the format of packet payloads may be non-standard where packet payloads could also include different wavelengths for increasing the volume of traffic. The advantage is obvious: the proposed switch could transport various types of traffic. An easily implemented architecture which can provide multicast services is also presented. An optical output buffer is designed to queue the packets if more than one incoming packet should reach to the same destination output port or including any waiting packets in optical output buffer that will be sent to the output port at a time slot. 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 fiber Bragg grating arrays for both input ports and output ports are designed for routing incoming packets using optical code division multiple access technology.

Acousto-Optical Evaluation Of Fiber Size In Wood Pulp

NASA Astrophysics Data System (ADS)

Dion, J. L.; Garceau, J. J.; Morissette, J. C.

1986-10-01

In the pulp and paper industry, the problem of regular and fast evaluation of wood fiber characteristics such as length and specific area is an important one. With this in view, we have been studying an acousto-optical technique based on the acoustic agglomeration of fibers in a water suspension, where a stationary ultrasonic field is created at about 150 kHz. Under the influence of radiation forces, fibers re-orient themselves parallel to the nodal planes of acoustic pressure, and regroup or agglomerate in these planes in different characteristic times. These are mesured by means of the light scattered at small angles. We have found that these times depend on the size distribution of fibers, particularly length. We present results obtained with an assortment of fiber types, under various experimental conditions which indicate eventual applications in the automatic control of pulp production.

Integration of power over fiber on RoF systems in different scenarios

NASA Astrophysics Data System (ADS)

Vázquez, C.; Montero, D. S.; Pinzón, P. J.; López-Cardona, J. D.; Contreras, P.; Tapetado, A.

2017-01-01

Future high capacity of the 5th Generation radio environment will boost transport networks to be adapted. The high bandwidth, together with stringent delay and jitter requirements, make dedicated optical connectivity a preferred solution for fronthaul. Those Radio Access Networks apart from higher capacity and lower latency should have higher energy efficiency. In order to cover this aspect, power over fiber has been pointed out as a key technology for that purpose having in mind that control plane will be centralized on future Cloud RAN and that sometimes Remote Radio Heads should be deployed in places lacking external power supply in order to fulfill the desired coverage. In this paper, different scenarios on potential demanding environments of power over fiber on Radio over Fiber systems such as automotive, in-house and remote mobile fronthaul will be discussed. Some tests on power over fiber systems based on different optical fibers are provided.

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.

DAQ application of PC oscilloscope for chaos fiber-optic fence system based on LabVIEW

NASA Astrophysics Data System (ADS)

Lu, Manman; Fang, Nian; Wang, Lutang; Huang, Zhaoming; Sun, Xiaofei

2011-12-01

In order to obtain simultaneously high sample rate and large buffer in data acquisition (DAQ) for a chaos fiber-optic fence system, we developed a double-channel high-speed DAQ application of a digital oscilloscope of PicoScope 5203 based on LabVIEW. We accomplished it by creating call library function (CLF) nodes to call the DAQ functions in the two dynamic link libraries (DLLs) of PS5000.dll and PS5000wrap.dll provided by Pico Technology Company. The maximum real-time sample rate of the DAQ application can reach 1GS/s. We can control the resolutions of the application at the sample time and data amplitudes by changing their units in the block diagram, and also control the start and end times of the sampling operations. The experimental results show that the application has enough high sample rate and large buffer to meet the demanding DAQ requirements of the chaos fiber-optic fence system.

Light driven optofluidic switch developed in a ZnO-overlaid microstructured optical fiber.

PubMed

Konidakis, Ioannis; Konstantaki, Maria; Tsibidis, George D; Pissadakis, Stavros

2015-11-30

A great challenge of Optofluidics remains the control of the fluidic properties of a photonic circuit by solely utilizing light. In this study, the development of a ZnO nanolayered microstructured optical fiber (MOF) Fabry-Perot interferometer is demonstrated, along with its fully reversible optofluidic switching behaviour. The actuation and switching principle is entirely based on the employment of light sources, i.e. UV 248 nm and green 532 nm lasers, while using modest irradiation doses. The synthesized ZnO within the MOF capillaries acts as a light triggered wettability transducer, allowing the controlled water filling and draining of the MOF Fabry-Perot cavity. The progression of the optofluidic cycle is monitored in situ with optical microscopy, while Fabry-Perot reflection spectra are monitored in real time to probe temporal infiltration behaviour. Finally, a first insight on the light triggered switching mechanism, employing photoluminescence and spectrophotometric measurements is presented. Results appear highly promising towards the design of smart in-fiber optofluidic light switching devices, suitable for actuating and sensing applications.

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

Bi-Tapered Fiber Sensor Using a Supercontinuum Light Source for a Broad Spectral Range

NASA Astrophysics Data System (ADS)

Garcia Mina, Diego Felipe

We describe the fabrication bi-tapered optical fiber sensors designed for shorter wavelength operation and we study their optical properties. The new sensing system designed and built for the project is a specialty optical fiber that is single-mode in the visible/near infrared wavelength region of interest. In fabricating the tapered fiber we control the taper parameters, such as the down-taper and up-taper rate, shape and length, and the fiber waist diameter and length. The sensing is mode is via the electromagnetic field, which is evanescent outside the optical fiber and is confined close to the fiber's surface (within a couple hundred nanometers). The fiber sensor system has multiple advantages as a compact, simple device with an ability to detected tiny changes in the refractive index. We developed a supercontinuum light source to provide a wide spectral wavelength range from visible to near IR. The source design was based on coupling light from a femtosecond laser in a photonic crystal fiber designed for high nonlinearity. The output light was efficiently coupled into the bi-tapered fiber sensor and good signal to noise was achieved across the wavelength region. The bi-tapered fiber starts and ends with a single mode fiber in the waist region there are many modes with different propagation constants that couple to the environment outside the fiber. The signals have a strong periodic component as the wavelength is scanned; we exploit the periodicity in the signal using a discrete Fourier transform analysis to correlate signal phase changes with the refractive index changes in the local environment. For small index changes we also measure a strong correlation with the dominant Fourier amplitude component. Our experiments show that our phase-based signal processing technique works well at shorter wavelengths and we extract a new feature, the Fourier amplitude, to measure the refractive index difference. We conducted experiments using aqueous medium with controlled refractive index, such as water-glycerol mixtures. We find sensitivity to changes in the refractive index close to 0.00002 in so-called Refractive Index Units (RIUs). That is smaller than reported in recent literature, but by no means a limiting value. The technique is not limited to aqueous solutions surrounding the fiber, but it can also be adapted to study volatile organic compounds. Future improvements in the fiber sensing system are discussed, including adding thin films to the surface for label-free detection and to draw the electromagnetic field to the fiber's surface.

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.

Wavefront sensing and adaptive control in phased array of fiber collimators

NASA Astrophysics Data System (ADS)

Lachinova, Svetlana L.; Vorontsov, Mikhail A.

2011-03-01

A new wavefront control approach for mitigation of atmospheric turbulence-induced wavefront phase aberrations in coherent fiber-array-based laser beam projection systems is introduced and analyzed. This approach is based on integration of wavefront sensing capabilities directly into the fiber-array transmitter aperture. In the coherent fiber array considered, we assume that each fiber collimator (subaperture) of the array is capable of precompensation of local (onsubaperture) wavefront phase tip and tilt aberrations using controllable rapid displacement of the tip of the delivery fiber at the collimating lens focal plane. In the technique proposed, this tip and tilt phase aberration control is based on maximization of the optical power received through the same fiber collimator using the stochastic parallel gradient descent (SPGD) technique. The coordinates of the fiber tip after the local tip and tilt aberrations are mitigated correspond to the coordinates of the focal-spot centroid of the optical wave backscattered off the target. Similar to a conventional Shack-Hartmann wavefront sensor, phase function over the entire fiber-array aperture can then be retrieved using the coordinates obtained. The piston phases that are required for coherent combining (phase locking) of the outgoing beams at the target plane can be further calculated from the reconstructed wavefront phase. Results of analysis and numerical simulations are presented. Performance of adaptive precompensation of phase aberrations in this laser beam projection system type is compared for various system configurations characterized by the number of fiber collimators and atmospheric turbulence conditions. The wavefront control concept presented can be effectively applied for long-range laser beam projection scenarios for which the time delay related with the double-pass laser beam propagation to the target and back is compared or even exceeds the characteristic time of the atmospheric turbulence change - scenarios when conventional target-in-the-loop phase-locking techniques fail.

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

[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.

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.

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

Damage detection in bridges through fiber optic structural health monitoring

NASA Astrophysics Data System (ADS)

Doornink, J. D.; Phares, B. M.; Wipf, T. J.; Wood, D. L.

2006-10-01

A fiber optic structural health monitoring (SHM) system was developed and deployed by the Iowa State University (ISU) Bridge Engineering Center (BEC) to detect gradual or sudden damage in fracture-critical bridges (FCBs). The SHM system is trained with measured performance data, which are collected by fiber optic strain sensors to identify typical bridge behavior when subjected to ambient traffic loads. Structural responses deviating from the trained behavior are considered to be signs of structural damage or degradation and are identified through analytical procedures similar to control chart analyses used in statistical process control (SPC). The demonstration FCB SHM system was installed on the US Highway 30 bridge near Ames, IA, and utilizes 40 fiber bragg grating (FBG) sensors to continuously monitor the bridge response when subjected to ambient traffic loads. After the data is collected and processed, weekly evaluation reports are developed that summarize the continuous monitoring results. Through use of the evaluation reports, the bridge owner is able to identify and estimate the location and severity of the damage. The information presented herein includes an overview of the SHM components, results from laboratory and field validation testing on the system components, and samples of the reduced and analyzed data.

All-fiber Devices Based on Photonic Crystal Fibers with Integrated Electrodes

NASA Astrophysics Data System (ADS)

Chesini, Giancarlo; Cordeiro, Cristiano M. B.; de Matos, Christiano J. S.; Fokine, Michael; Carvalho, Isabel C. S.; Knighf, Jonathan C.

2008-10-01

A special kind of microstructured optical fiber was proposed and manufactured where, as well as the holey region (solid core and silica-air cladding), the fiber has also two large holes for electrode insertion. Bi-Sn and Au-Sn alloys were selectively inserted in those holes forming two parallel, continuous and homogeneous internal electrodes. We demonstrated the production of a monolithic device and its use to externally control some of the guidance properties (e.g. polarization) of the fiber.

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

PubMed Central

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

2013-01-01

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

Fiber Scrambling for Extreme Doppler Precision

NASA Astrophysics Data System (ADS)

Spronck, Julien; Kaplan, Z.; Fischer, D.

2011-09-01

The detection of Earth-like exoplanets with the radial velocity method requires extreme Doppler precision and long-term stability in order to measure tiny reflex velocities in the host star. Recent planet searches have led to the detection of so called “super-Earths” (up to a few Earth masses) that induce radial velocity changes of about 1 m/s. However, the detection of true Earth analogs requires a precision of 10 cm/s. One of the factors limiting Doppler precision is variation in the Point Spread Function (PSF) from observation to observation due to changes in the illumination of the slit and spectrograph optics. Thus, this stability has become a focus of current instrumentation work. Fiber optics have been used since the 1980’s to couple telescopes to high-precision spectrographs, initially for simpler mechanical design and control. However, fiber optics are also naturally efficient scramblers. Scrambling refers to a fiber’s ability to produce an output beam independent of input. Our research is focused on understanding the scrambling properties of fibers with different geometries (circular, square, octagonal), different lengths and fiber sizes. Another important parameter when it comes to fibers is the so-called focal ratio degradation (FRD), which accounts for a different (faster) focal ratio after the fiber than the one sent into the fiber. In this paper, we will present new insight on fiber scrambling, FRD and what we call fiber personality, which describes differing behaviors for supposedly identical fiber.

Geomembrane barriers using integral fiber optics to monitor barrier integrity

DOEpatents

Staller, G.E.; Wemple, R.P.

1996-10-22

This invention provides a geomembrane or geotextile with embedded optical sensors that are used to monitor the status of containment site barriers. Fiber optic strands are used to form the sensors that can detect and monitor conditions at the sites such as breaches, slope creep, subsidence, leachate levels, fires, and types of materials present or leaking from the site. The strands are integral to the membrane or textile materials. The geosynthetic membrane is deployed at the site in a fashion similar to carpet laying. Edges of the membrane or textile are joined to form a liner and the ends of the membrane or textile become the connection zones for obtaining signals from the sensors. A connection interface with a control system to generate Optical Time Delay Response or other light signals for transmission to the optic fiber strands or sensors and also to receive reflected signals from the sensors is included in the system. Software to interpret the sensor signals can be used in the geosynthetic monitoring system. 6 figs.

Geomembrane barriers using integral fiber optics to monitor barrier integrity

DOEpatents

Staller, George E.; Wemple, Robert P.

1996-01-01

This invention provides a geomembrane or geotextile with embedded optical sensors that are used to monitor the status of containment site barriers. Fiber optic strands are used to form the sensors that can detect and monitor conditions at the sites such as breaches, slope creep, subsidence, leachate levels, fires, and types of materials present or leaking from the site. The strands are integral to the membrane or textile materials. The geosythetic membrane is deployed at the site in a fashion similar to carpet laying. Edges of the membrane or textile are joined to form a liner and the ends of the membrane or textile become the connection zones for obtaining signals from the sensors. A connection interface with a control system to generate Optical Time Delay Response or other light signals for transmission to the optic fiber strands or sensors and also to receive reflected signals from the sensors is included in the system. Software to interpret the sensor signals can be used in the geosythetic monitoring system.

Fast Interrogation of Fiber Bragg Gratings with Electro-Optical Dual Optical Frequency Combs

PubMed Central

Posada-Roman, Julio E.; Garcia-Souto, Jose A.; Poiana, Dragos A.; Acedo, Pablo

2016-01-01

Optical frequency combs (OFC) generated by electro-optic modulation of continuous-wave lasers provide broadband coherent sources with high power per line and independent control of line spacing and the number of lines. In addition to their application in spectroscopy, they offer flexible and optimized sources for the interrogation of other sensors based on wavelength change or wavelength filtering, such as fiber Bragg grating (FBG) sensors. In this paper, a dual-OFC FBG interrogation system based on a single laser and two optical-phase modulators is presented. This architecture allows for the configuration of multimode optical source parameters such as the number of modes and their position within the reflected spectrum of the FBG. A direct read-out is obtained by mapping the optical spectrum onto the radio-frequency spectrum output of the dual-comb. This interrogation scheme is proposed for measuring fast phenomena such as vibrations and ultrasounds. Results are presented for dual-comb operation under optimized control. The optical modes are mapped onto detectable tones that are multiples of 0.5 MHz around a center radiofrequency tone (40 MHz). Measurements of ultrasounds (40 kHz and 120 kHz) are demonstrated with this sensing system. Ultrasounds induce dynamic strain onto the fiber, which generates changes in the reflected Bragg wavelength and, hence, modulates the amplitude of the OFC modes within the reflected spectrum. The amplitude modulation of two counterphase tones is detected to obtain a differential measurement proportional to the ultrasound signal. PMID:27898043

Fast Interrogation of Fiber Bragg Gratings with Electro-Optical Dual Optical Frequency Combs.

PubMed

Posada-Roman, Julio E; Garcia-Souto, Jose A; Poiana, Dragos A; Acedo, Pablo

2016-11-26

Optical frequency combs (OFC) generated by electro-optic modulation of continuous-wave lasers provide broadband coherent sources with high power per line and independent control of line spacing and the number of lines. In addition to their application in spectroscopy, they offer flexible and optimized sources for the interrogation of other sensors based on wavelength change or wavelength filtering, such as fiber Bragg grating (FBG) sensors. In this paper, a dual-OFC FBG interrogation system based on a single laser and two optical-phase modulators is presented. This architecture allows for the configuration of multimode optical source parameters such as the number of modes and their position within the reflected spectrum of the FBG. A direct read-out is obtained by mapping the optical spectrum onto the radio-frequency spectrum output of the dual-comb. This interrogation scheme is proposed for measuring fast phenomena such as vibrations and ultrasounds. Results are presented for dual-comb operation under optimized control. The optical modes are mapped onto detectable tones that are multiples of 0.5 MHz around a center radiofrequency tone (40 MHz). Measurements of ultrasounds (40 kHz and 120 kHz) are demonstrated with this sensing system. Ultrasounds induce dynamic strain onto the fiber, which generates changes in the reflected Bragg wavelength and, hence, modulates the amplitude of the OFC modes within the reflected spectrum. The amplitude modulation of two counterphase tones is detected to obtain a differential measurement proportional to the ultrasound signal.

Adiabatic tapered optical fiber fabrication in two step etching

NASA Astrophysics Data System (ADS)

Chenari, Z.; Latifi, H.; Ghamari, S.; Hashemi, R. S.; Doroodmand, F.

2016-01-01

A two-step etching method using HF acid and Buffered HF is proposed to fabricate adiabatic biconical optical fiber tapers. Due to the fact that the etching rate in second step is almost 3 times slower than the previous droplet etching method, terminating the fabrication process is controllable enough to achieve a desirable fiber diameter. By monitoring transmitted spectrum, final diameter and adiabaticity of tapers are deduced. Tapers with losses about 0.3 dB in air and 4.2 dB in water are produced. The biconical fiber taper fabricated using this method is used to excite whispering gallery modes (WGMs) on a microsphere surface in an aquatic environment. So that they are suitable to be used in applications like WGM biosensors.

Long-term stable coherent beam combination of independent femtosecond Yb-fiber lasers.

PubMed

Tian, Haochen; Song, Youjian; Meng, Fei; Fang, Zhanjun; Hu, Minglie; Wang, Chingyue

2016-11-15

We demonstrate coherent beam combination between independent femtosecond Yb-fiber lasers by using the active phase locking of relative pulse timing and the carrier envelope phase based on a balanced optical cross-correlator and extracavity acoustic optical frequency shifter, respectively. The broadband quantum noise of femtosecond fiber lasers is suppressed via precise cavity dispersion control, instead of complicated high-bandwidth phase-locked loop design. Because of reduced quantum noise and a simplified phase-locked loop, stable phase locking that lasts for 1 hour has been obtained, as verified via both spectral interferometry and far-field beam interferometry. The approach can be applied to coherent pulse synthesis, as well as to remote frequency comb connection, allowing a practical all-fiber configuration.

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.

Characterization and Oxidation Behavior of Rayon-Derived Carbon Fibers

NASA Technical Reports Server (NTRS)

Jacobson, Nathan; Hull, David

2010-01-01

Rayon-derived fibers are the central constituent of reinforced carbon/ carbon (RCC) composites. Optical, scanning electron, and transmission electron microscopy were used to characterize the as-fabricated fibers and the fibers after oxidation. Oxidation rates were measured with weight loss techniques in air and oxygen. The as-received fibers are approximately 10 micron in diameter and characterized by grooves or crenulations around the edges. Below 800 C, in the reaction-controlled region, preferential attack began in the crenulations and appeared to occur down fissures in the fibers.

Role of Retinal Nerve Fiber Layer Thickness and Optic Disk Measurement by OCT on Early Diagnosis of Glaucoma.

PubMed

Hua, Zanmei; Fang, Qiuyun; Sha, Xiangyin; Yang, Ruiming; Hong, Zuopeng

2015-03-01

Glaucoma is an eye disease that can lead to irreversible optic nerve damage and cause blindness. Optical coherence tomography (OCT) allows an early diagnosis of glaucoma by the measurements of the retinal nerve fiber and optic disc parameters. A retrospective study was designed to analyze the effects of the measurement of the retinal nerve fiber layer (RNFL) thickness and the optic disc tomography by spectral-domain OCT on the early diagnosis of suspected glaucoma and primary open angle glaucoma (POAG). This was a clinical case-control study. The RNFL thickness around the optic disc and optic disk tomographic parameters of the control (n = 51, 98 eyes), suspected glaucoma (n = 81, 146 eyes), and POAG groups (n = 55, 106 eyes) were measured by OCT. The parameters included superior, inferior, nasal and temporal mean RNFL thickness, disc area (DA), cup area (CA), rim area (RA), disc volume (DV), cup volume (CV), rim volume (RV), cup/disc area ratio (CA/DA), rim/disc area ratio (RA/DA), cup/disc volume ratio (CV/DV) and rim/disc volume ratio (RV/DV). Superior, nasal, and mean RNFL parameters, DA, CA,RA, DV, CV, CA/DA, RA/DA, CV/DV and RV/DV significantly differed among three groups by single-factorial ANOVA. Inferior and temporal RNFL thickness significantly differed between the control and POAG groups. No significant difference was observed in RV among three groups. In the POAG group, the maximum area under the ROC curve (AROC) of mean RNFL thickness was 0.845. The maximum AROC of optic disk parameters was RA/DA (0.998), followed by CA/DA (0.997). The AROC of CA, RA, CV, and DV were all > 0.900. OCT may serve as a useful diagnostic modality in distinguishing suspected glaucoma from POAG.

Robust Modal Filtering and Control of the X-56A Model with Simulated Fiber Optic Sensor Failures

NASA Technical Reports Server (NTRS)

Suh, Peter M.; Chin, Alexander W.; Marvis, Dimitri N.

2014-01-01

The X-56A aircraft is a remotely-piloted aircraft with flutter modes intentionally designed into the flight envelope. The X-56A program must demonstrate flight control while suppressing all unstable modes. A previous X-56A model study demonstrated a distributed-sensing-based active shape and active flutter suppression controller. The controller relies on an estimator which is sensitive to bias. This estimator is improved herein, and a real-time robust estimator is derived and demonstrated on 1530 fiber optic sensors. It is shown in simulation that the estimator can simultaneously reject 230 worst-case fiber optic sensor failures automatically. These sensor failures include locations with high leverage (or importance). To reduce the impact of leverage outliers, concentration based on a Mahalanobis trim criterion is introduced. A redescending M-estimator with Tukey bisquare weights is used to improve location and dispersion estimates within each concentration step in the presence of asymmetry (or leverage). A dynamic simulation is used to compare the concentrated robust estimator to a state-of-the-art real-time robust multivariate estimator. The estimators support a previously-derived mu-optimal shape controller. It is found that during the failure scenario, the concentrated modal estimator keeps the system stable.

Robust Modal Filtering and Control of the X-56A Model with Simulated Fiber Optic Sensor Failures

NASA Technical Reports Server (NTRS)

Suh, Peter M.; Chin, Alexander W.; Mavris, Dimitri N.

2016-01-01

The X-56A aircraft is a remotely-piloted aircraft with flutter modes intentionally designed into the flight envelope. The X-56A program must demonstrate flight control while suppressing all unstable modes. A previous X-56A model study demonstrated a distributed-sensing-based active shape and active flutter suppression controller. The controller relies on an estimator which is sensitive to bias. This estimator is improved herein, and a real-time robust estimator is derived and demonstrated on 1530 fiber optic sensors. It is shown in simulation that the estimator can simultaneously reject 230 worst-case fiber optic sensor failures automatically. These sensor failures include locations with high leverage (or importance). To reduce the impact of leverage outliers, concentration based on a Mahalanobis trim criterion is introduced. A redescending M-estimator with Tukey bisquare weights is used to improve location and dispersion estimates within each concentration step in the presence of asymmetry (or leverage). A dynamic simulation is used to compare the concentrated robust estimator to a state-of-the-art real-time robust multivariate estimator. The estimators support a previously-derived mu-optimal shape controller. It is found that during the failure scenario, the concentrated modal estimator keeps the system stable.

Development of SPR temperature sensor using Au/TiO2 on hetero-core optical fiber

NASA Astrophysics Data System (ADS)

Kitagawa, Sho; Yamazaki, Hiroshi; Hosoki, Ai; Nishiyama, Michiko; Watanabe, Kazuhiro

2016-03-01

This paper describes a novel temperature sensor based on a hetero-core structured fiber optic surface plasmon resonance (SPR) sensor with multi-layer thin film of gold (Au) and titanium dioxide (TiO2). Temperature condition is an essential parameter in chemical plants for avoiding fire accident and controlling qualities of chemical substances. Several fiber optic temperature sensors have been developed for some advantages such as immunity to electromagnetic interference, corrosion resistance and no electrical leakage. The proposed hetero-core fiber optic SPR sensor detects temperature condition by measuring slight refractive index changes of TiO2 which has a large thermo-optic coefficient. We experimentally confirmed that the SPR resonant wavelength in the hetero-core SPR sensor with coating an Au film which slightly depended on temperature changes in the range from 20 °C to 80 °C. In addition, it was experimentally shown that the proposed SPR temperature sensor with multi-layer film of Au and TiO2 had the SPR resonant wavelength shift of 1.6 nm due to temperature change from -10 °C to 50 °C. As a result, a series of experiments successfully demonstrated that the proposed sensor was able to detect temperature directly depending on the thermo-optic effect of TiO2.

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.

Performance of Integrated Fiber Optic, Piezoelectric, and Shape Memory Alloy Actuators/Sensors in Thermoset Composites

NASA Technical Reports Server (NTRS)

Trottier, C. Michael

1996-01-01

Recently, scientists and engineers have investigated the advantages of smart materials and structures by including actuators in material systems for controlling and altering the response of structural environments. Applications of these materials systems include vibration suppression/isolation, precision positioning, damage detection and tunable devices. Some of the embedded materials being investigated for accomplishing these tasks include piezoelectric ceramics, shape memory alloys, and fiber optics. These materials have some benefits and some shortcomings; each is being studied for use in active material design in the SPICES (Synthesis and Processing of Intelligent Cost Effective Structures) Consortium. The focus of this paper concerns the manufacturing aspects of smart structures by incorporating piezoelectric ceramics, shape memory alloys and fiber optics in a reinforced thermoset matrix via resin transfer molding (RTM).

A Self-Synchronized Optoelectronic Oscillator based on an RTD Photo-Detector and a Laser Diode

PubMed Central

Romeira, Bruno; Seunarine, Kris; Ironside, Charles N.; Kelly, Anthony E.; Figueiredo, José M. L.

2013-01-01

We propose and demonstrate a simple and stable low-phase noise optoelectronic oscillator (OEO) that uses a laser diode, an optical fiber delay line and a resonant tunneling diode (RTD) free-running oscillator that is monolithic integrated with a waveguide photo-detector. The RTD-OEO exhibits single-side band phase noise power below −100 dBc/Hz with more than 30 dB noise suppression at 10 kHz from the center free-running frequency for fiber loop lengths around 1.2 km. The oscillator power consumption is below 0.55 W, and can be controlled either by the injected optical power or the fiber delay line. The RTD-OEO stability is achieved without using other high-speed optical/optoelectronic components and amplification. PMID:23814452

"Reliability Of Fiber Optic Lans"

NASA Astrophysics Data System (ADS)

Code n, Michael; Scholl, Frederick; Hatfield, W. Bryan

1987-02-01

Fiber optic Local Area Network Systems are being used to interconnect increasing numbers of nodes. These nodes may include office computer peripherals and terminals, PBX switches, process control equipment and sensors, automated machine tools and robots, and military telemetry and communications equipment. The extensive shared base of capital resources in each system requires that the fiber optic LAN meet stringent reliability and maintainability requirements. These requirements are met by proper system design and by suitable manufacturing and quality procedures at all levels of a vertically integrated manufacturing operation. We will describe the reliability and maintainability of Codenoll's passive star based systems. These include LAN systems compatible with Ethernet (IEEE 802.3) and MAP (IEEE 802.4), and software compatible with IBM Token Ring (IEEE 802.5). No single point of failure exists in this system architecture.

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

High-speed optical feeder-link system using adaptive optics

NASA Astrophysics Data System (ADS)

Arimoto, Yoshinori; Hayano, Yutaka; Klaus, Werner

1997-05-01

We propose a satellite laser communication system between a ground station and a geostationary satellite, named high- speed optical feeder link system. It is based on the application of (a) high-speed optical devices, which have been developed for ground-based high-speed fiber-optic communications, and (b) the adaptive optics which compensates wavefront distortions due to atmospheric turbulences using a real time feedback control. A link budget study shows that a system with 10-Gbps bit-rate are available assuming the state-of-the-art device performance of the Er-doped fiber amplifier. We further discuss preliminary measurement results of the atmospheric turbulence at the telescope site in Tokyo, and present current study on the design of the key components for the feeder-link laser transceiver.

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).

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.

Photonic crystal fibre for industrial laser delivery

NASA Astrophysics Data System (ADS)

O'Driscoll, E. J.; McDonald, J.; Morgan, S.; Simpson, G.; Sidhu, J.; Baggett, J. C.; Hayes, J. R.; Petrovich, M. N.; Finazzi, V.; Polletti, F.; Richardson, D. J.; Horley, R.; Harker, A.; Grunewald, P.; Allott, R.; Judd, E.

2006-12-01

Fiber delivery of intense laser radiation is important for a broad range of application sectors, from medicine through to industrial laser processing of materials, and offers many practical system benefits relative to free space solutions. In recent years, photonic crystal fiber technology has revolutionized the dynamic field of optical fibers, bringing with them a wide range of novel optical properties that make them ideally suited to power delivery with unparalleled control over the beam properties. The DTI funded project: Photonic Fibers for Industrial beam DELivery (PFIDEL), aims to develop novel fiber geometries for use as a delivery system for high power industrial lasers and to assess their potential in a range of "real" industrial applications. In this paper we review, from an industrial laser user perspective, the advantages of each of the fibers studied under PFIDEL. We present results of application demonstrations and discuss how these fibers can positively impact the field of industrial laser systems and processes, in particular for direct write and micromachining applications.

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.

Pathogen detection using evanescent-wave fiber optic biosensor

NASA Astrophysics Data System (ADS)

Ferreira, Aldo P.; Werneck, Marcelo M.; Ribeiro, R. M.; Lins, U. G.

1999-07-01

This paper describes a real time optical biosensor that utilizes the evanescent field technique for monitoring microorganisms in hospital environment. The biosensor monitors interactions between the analytic (bacteria) and the evanescent field of an optical fiber passing through the culture media where the bacteria grows. The objective is to monitor atmospheres in hospital areas for the Staphylococcus aureus and Streptococcus pneumonia. The results lead us the conclusion that this kind of sensor presents quick response, good performance, easy of construction and low cost. We expect that the sensor will be of great help in controlling the hospital environment.

Optical fiber sensors: Systems and applications. Volume 2

NASA Astrophysics Data System (ADS)

Culshaw, Brian; Dakin, John

State-of-the-art fiber-optic (FO) sensors and their applications are described in chapters contributed by leading experts. Consideration is given to interferometers, FO gyros, intensity- and wavelength-based sensors and optical actuators, Si in FO sensors, point-sensor multiplexing principles, and distributed FO sensor systems. Also examined are chemical, biochemical, and medical sensors; physical and chemical sensors for process control; FO-sensor applications in the marine and aerospace industries; FO-sensor monitoring systems for security and safety, structural integrity, NDE, and the electric-power industry; and the market situation for FO-sensor technology. Diagrams, drawings, graphs, and photographs are provided.

Method of targeted delivery of laser beam to isolated retinal rods by fiber optics.

PubMed

Sim, Nigel; Bessarab, Dmitri; Jones, C Michael; Krivitsky, Leonid

2011-11-01

A method of controllable light delivery to retinal rod cells using an optical fiber is described. Photo-induced current of the living rod cells was measured with the suction electrode technique. The approach was tested with measurements relating the spatial distribution of the light intensity to photo-induced current. In addition, the ion current responses of rod cells to polarized light at two different orientation geometries of the cells were studied.

Coherent optical monolithic phased-array antenna steering system

DOEpatents

Hietala, Vincent M.; Kravitz, Stanley H.; Vawter, Gregory A.

1994-01-01

An optical-based RF beam steering system for phased-array antennas comprising a photonic integrated circuit (PIC). The system is based on optical heterodyning employed to produce microwave phase shifting by a monolithic PIC constructed entirely of passive components. Microwave power and control signal distribution to the antenna is accomplished by optical fiber, permitting physical separation of the PIC and its control functions from the antenna. The system reduces size, weight, complexity, and cost of phased-array antenna systems.

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.

An Evaluation of Peripapillary Retinal Nerve Fiber Layer Thickness in Children With Epilepsy Receiving Treatment of Valproic Acid.

PubMed

Dereci, Selim; Koca, Tuğba; Akçam, Mustafa; Türkyilmaz, Kemal

2015-07-01

We investigated the peripapillary retinal nerve fiber layer thickness with optical coherence tomography in epileptic children receiving valproic acid monotherapy. The study was conducted on children aged 8-16 years who were undergoing valproic acid monotherapy for epilepsy. The study group comprised a total of 40 children who met the inclusion criteria and 40 healthy age- and sex-matched children as a control group. Children with at least a 1-year history of epilepsy and taking 10-40 mg/kg/day treatment were included in the study. Peripapillary retinal nerve fiber layer thickness measurements were performed using Cirrus HD optical coherence tomography. All children and parents were informed about the study and informed consent was obtained from the parents of all the participants. The study group included 21 girls and 19 boys with a mean age of 10.6 ± 2.3 years. According to the results of optical coherence tomography measurements, the mean peripapillary retinal nerve fiber layer thickness was 91.6 ± 9.7 in the patient group and 95.5 ± 7.4 μm in the control group (P < 0.05). The superior peripapillary retinal nerve fiber layer thickness was 112.0 ± 13.2 in the patient group and 120.0 ± 14.7 μm in the control group (P < 0.02). According to the results of both measurements, the peripapillary retinal nerve fiber layer thickness was significantly lower in the patient group. Neither color vision loss nor visual field examination abnormality could be documented. According to the optical coherence tomography measurements, the average and superior peripapillary retinal nerve fiber layer thicknesses were thinner in patients with epilepsy who were receiving valproic acid monotherapy compared with healthy children. This situation can lead to undesirable results in terms of eye health. New studies are needed to investigate whether these findings are the result of epilepsy or can be attributed to valproic acid and whether there are adverse effects of valproic acid later in life. Copyright © 2015 Elsevier Inc. All rights reserved.

Novel optical interconnect devices applying mask-transfer self-written method

NASA Astrophysics Data System (ADS)

Ishizawa, Nobuhiko; Matsuzawa, Yusuke; Tokiwa, Yu; Nakama, Kenichi; Mikami, Osamu

2012-01-01

The introduction of optical interconnect technology is expected to solve problems of conventional electric wiring. One of the promising technologies realizing optical interconnect is the self-written waveguide (SWW) technology with lightcurable resin. We have developed a new technology of the "Mask-Transfer Self-Written (MTSW)" method. This new method enables fabrication of arrayed M x N optical channels at one shot of UV-light. Using this technology, several new optical interconnect devices and connection technologies have been proposed and investigated. In this paper, first, we introduce MTSW method briefly. Next, we show plug-in alignment approach using optical waveguide plugs (OWP) and a micro-hole array (MHA) which are made of the light-curable resin. Easy and high efficiency plug-in alignment between fibers and an optoelectronic-printed wiring board (OE-PWB), between a fiber and a VCSEL, so on will be feasible. Then, we propose a new three-dimensional (3D) branch waveguide. By controlling the irradiating angle through the photomask aperture, it will be possible to fabricate 2-branch and 4-branch waveguides with a certain branch angle. The 3D branch waveguide will be very promising in the future optical interconnects and coupler devices of the multicore optical fiber.

Laser beam uniformity and stability using homogenizer-based fiber optic launch method: square core fiber delivery

NASA Astrophysics Data System (ADS)

Lizotte, Todd E.

2011-03-01

Over the years, technological achievements within the laser medical diagnostic, treatment, and therapy markets have led to ever increasing requirements for greater control of critical laser beam parameters. Increased laser power/energy stabilization, temporal and spatial beam shaping and flexible laser beam delivery systems with ergonomic focusing or imaging lens systems are sought by leading medical laser system producers. With medical procedures that utilize laser energy, there is a constant emphasis on reducing adverse effects that come about by the laser itself or its optical system, but even when these variables are well controlled the medical professional will still need to deal with the multivariate nature of the human body. Focusing on the variables that can be controlled, such as accurate placement of the laser beam where it will expose a surface being treated as well as laser beam shape and uniformity is critical to minimizing adverse conditions. This paper covers the use of fiber optic beam delivery as a means of defining the beam shape (intensity/power distribution uniformity) at the target plane as well as the use of fiber delivery as a means to allow more flexible articulation of the laser beam over the surface being treated. The paper will present a new concept of using a square core fiber beam delivery design utilizing a unique micro lens array (MLA) launch method that improves the overall stability of the system, by minimizing the impact of the laser instability. The resulting performance of the prototype is presented to demonstrate its stability in comparison to simple lens launch techniques, with an emphasis on homogenization and articulated fiber delivery.

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