WorldWideScience

Sample records for based optical fibres

  1. Optical fibres

    CERN Multimedia

    1992-01-01

    These optical fibres are used to detect particles passing through in bunches. Made from scintillating material, the fibres glow when a high energy particle passes through them. These detectors are known as spaghetti detectors and are used to measure the energy of particles.

  2. Optical Fibre Sensors Using Graphene-Based Materials: A Review.

    Science.gov (United States)

    Hernaez, Miguel; Zamarreño, Carlos R; Melendi-Espina, Sonia; Bird, Liam R; Mayes, Andrew G; Arregui, Francisco J

    2017-01-14

    Graphene and its derivatives have become the most explored materials since Novoselov and Geim (Nobel Prize winners for Physics in 2010) achieved its isolation in 2004. The exceptional properties of graphene have attracted the attention of the scientific community from different research fields, generating high impact not only in scientific journals, but also in general-interest newspapers. Optical fibre sensing is one of the many fields that can benefit from the use of these new materials, combining the amazing morphological, chemical, optical and electrical features of graphene with the advantages that optical fibre offers over other sensing strategies. In this document, a review of the current state of the art for optical fibre sensors based on graphene materials is presented.

  3. Development of evanescent wave absorbance-based fibre-optic ...

    Indian Academy of Sciences (India)

    Abstract. Development of chemical and biochemical sensors is the current need of the society. In this report, we present our investigation on the development of a label-free fibre-optic biosensor based on evanescent wave absorbance to detect the presence of an- alytes such as bacteria, virus and some clinically important ...

  4. Optical measuring system with an interrogator and a polymer-based single-mode fibre optic sensor system

    DEFF Research Database (Denmark)

    2017-01-01

    The present invention relates to an optical measuring system comprising a polymer-based single-mode fibre-optic sensor system (102), an optical interrogator (101), and an optical arrangement (103) interconnecting the optical interrogator (101) and the polymer-based single-mode fibre-optic sensor...... system (102). The invention further relates to an optical interrogator adapted to be connected to a polymer-based single-mode fibre-optic sensor system via an optical arrangement. The interrogator comprises a broadband light source arrangement (104) and a spectrum analysing arrangement which receives...... and analyses light reflected from the polymer-based single- mode fibre-optic sensor system....

  5. Optical Fibre Temperature Sensor Based On A Blackbody Radiation

    Science.gov (United States)

    Hypszer, Ryszard; Plucinski, Jerzy; Wierzba, Henryk J.

    1990-01-01

    The principle of operation of the fibre optical temperature sensor based on a blackbody radiation and its construction model is given in the paper. A quartz rod of 0.6 mm diameter and 20 cm length with a blackbody cavity at the one end was used to construct the sensor. The cavity was made by vacuum evaporation of a chromium layer and a silicone monooxide layer was used as a protection. Infrared radiation is transmitted by the fibre optic to the detection circuit. This sensor enables temperature measurement from 400 to 1200°C. The range of measurement is determined by the detection sensitivity and by rod softening. The resolution is of the order of 10-2°C. The sensor calibration was done by using PtRh1O-Pt thermocouple.

  6. Optical fibre microwire sensors

    OpenAIRE

    Brambilla, G.; Belal, Mohammad; Jung, Y.; Song, Z.; Xu, F.; Newson, T.P.; Richardson, D.J.

    2011-01-01

    This paper reviews sensing applications of optical fibre microwires and nanowires. In addition to the usual benefits of sensors based on optical fibres, these sensors are extremely compact and have fast response speeds. In this review sensors will be grouped in three categories according to their morphology: linear sensors, resonant sensors and tip sensors. While linear and resonant sensors mainly exploit the fraction of power propagating outside the microwire physical boundary, tip sensors t...

  7. Annealing effects on strain and stress sensitivity of polymer optical fibre based sensors

    DEFF Research Database (Denmark)

    Pospori, A.; Marques, C. A. F.; Zubel, M. G.

    2016-01-01

    The annealing effects on strain and stress sensitivity of polymer optical fibre Bragg grating sensors after their photoinscription are investigated. PMMA optical fibre based Bragg grating sensors are first photo-inscribed and then they were placed into hot water for annealing. Strain, stress...... fibre tends to increase the strain, stress and force sensitivity of the photo-inscribed sensor....

  8. Fabrication of silicon based glass fibres for optical communication

    Indian Academy of Sciences (India)

    Silicon based glass fibres are fabricated by conventional fibre drawing process. First, preform fabrication is carried out by means of conventional MCVD technique by using various dopants such as SiCl4, GeCl4, POCl3, and FeCl3. The chemicals are used in such a way that step index single mode fibre can be drawn.

  9. Fabrication of silicon based glass fibres for optical communication

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Silicon based glass fibres are fabricated by conventional fibre drawing process. First, preform fabrication is carried out by means of conventional MCVD technique by using various dopants such as SiCl4,. GeCl4, POCl3, and FeCl3. The chemicals are used in such a way that step index single mode fibre can be.

  10. Fabrication of polymer-based reflowed microlenses on optical fibre ...

    Indian Academy of Sciences (India)

    imaging fibres with custom made multiple lenses configuration can subdue such limitations by enhancing the illumination areas as well as acceptance cone for imaging. Integration of these lenses on the optical fibre is another issue which limits application. This paper incorporates the differential thickness technique to show ...

  11. Single-mode optical fibres

    CERN Document Server

    Cancellieri, G

    1991-01-01

    This book describes signal propagation in single-mode optical fibres for telecommunication applications. Such description is based on the analysis of field propagation, considering waveguide properties and also some of the particular characteristics of the material fibre. The book covers such recent advances as, coherent transmissions; optical amplification; MIR fibres; polarization maintaining; polarization diversity and photon counting.

  12. Fun with Optical Fibres

    Science.gov (United States)

    Alti, Kamlesh

    2017-01-01

    Optical fibres play a very crucial role in today's technologies. Academic courses in optical fibres start at the undergraduate level. Nevertheless, student's curiosity towards optical fibres starts from the school level. In this paper, some fun experiments have been designed for both school and college students, which have some concrete…

  13. Fibre-optical microendoscopy.

    Science.gov (United States)

    Gu, M; Bao, H; Kang, H

    2014-04-01

    Microendoscopy has been an essential tool in exploring micro/nano mechanisms in vivo due to high-quality imaging performance, compact size and flexible movement. The investigations into optical fibres, micro-scanners and miniature lens have boosted efficiencies of remote light delivery to sample site and signal collection. Given the light interaction with materials in the fluorescence imaging regime, this paper reviews two classes of compact microendoscopy based on a single fibre: linear optical microendoscopy and nonlinear optical microendoscopy. Due to the fact that fluorescence occurs only in the focal volume, nonlinear optical microendoscopy can provide stronger optical sectioning ability than linear optical microendoscopy, and is a good candidate for deep tissue imaging. Moreover, one-photon excited fluorescence microendoscopy as the linear optical microendoscopy suffers from severe photobleaching owing to the linear dependence of photobleaching rate on excitation laser power. On the contrary, nonlinear optical microendoscopy, including two-photon excited fluorescence microendoscopy and second harmonic generation microendoscopy, has the capability to minimize or avoid the photobleaching effect at a high excitation power and generate high image contrast. The combination of various nonlinear signals gained by the nonlinear optical microendoscopy provides a comprehensive insight into biophenomena in internal organs. Fibre-optical microendoscopy overcomes physical limitations of traditional microscopy and opens up a new path to achieve early cancer diagnosis and microsurgery in a minimally invasive and localized manner. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

  14. Optical fibres

    CERN Document Server

    Geisler, J; Boutruche, J P

    1986-01-01

    Optical Fibers covers numerous research works on the significant advances in optical fibers, with particular emphasis on their application.This text is composed of three parts encompassing 15 chapters. The first part deals with the manufacture of optical fibers and the materials used in their production. The second part describes optical-fiber connectors, terminals and branches. The third part is concerned with the major optoelectronic components encountered in optical-communication systems.This book will be of value to research scientists, engineers, and patent workers.

  15. Temperature-Insensitive Fibre-Optic Acceleration Sensor Based on Intensity-Referenced Fibre Bragg Gratings

    International Nuclear Information System (INIS)

    Li-Qun, Sun; Bo, Dong; Yong-Xin, Wang; LALLY, Evan; An-Bo, Wang

    2008-01-01

    A temperature-insensitive acceleration sensor using two fibre Bragg gratings (FBGs), based on reflection spectrum intensity modulation and optical power detection, is proposed and demonstrated. A cantilever beam is used to generate acceleration-induced axial strain along two sensing gratings, which are glued on the two opposite surfaces of the beam. Because the two gratings operate within the linear spectral range of a light source, formed by a thermally-tunable extrinsic Fabry-Perot optical filter, the intensity difference of the two reflections from the gratings is proportional to the acceleration applied. This eliminates the need for sophisticated wavelength interrogation of the gratings, and it also endows the sensor with immunity to temperature variation. Compared with a commercial micromachined accelerometer, the sensor is proven to be capable of accurately detecting acceleration

  16. Microstructured polymer optical fibres

    CERN Document Server

    Large, Maryanne; Barton, Geoff; van Eijkelenborg, Martijn A

    2008-01-01

    Microstructured Polymer Optical Fibres describes the optical properties of microstructured fibres, how they are made and modelled, and outlines some potential applications. These applications include areas where polymer fibres are already used, such as high-data rate transmission for Fibre-to-the Home or within cars, as well as completely new areas such as the photonic bandgap transmission of ""difficult"" wavelengths. Emphasising a conceptual understanding of the underlying physics, Microstructured Polymer Optical Fibres is clearly written, and includes numerous illustrations. It provides an

  17. Optic axis determination by fibre-based polarization-sensitive swept-source optical coherence tomography.

    Science.gov (United States)

    Lu, Zenghai; Kasaragod, Deepa K; Matcher, Stephen J

    2011-02-21

    We describe a fibre-based variable-incidence angle (VIA) polarization-sensitive swept-source optical coherence tomography (PS-SS-OCT) system to determine the 3D optical axis of birefringent biological tissues. Single-plane VIA-PS-OCT is also explored which requires measurement of the absolute fast-axis orientation. A state-of-the-art PS-SS-OCT system with some improvements both in hardware and software was used to determine the apparent optical birefringence of equine tendon for a number of different illumination directions. Polar and azimuthal angles of cut equine tendon were produced by the VIA method and compared with the nominal values. A quarter waveplate (QWP) and equine tendon were used as test targets to validate the fast-axis measurements using the system. Polar and azimuthal angles of cut equine tendon broadly agreed with the expected values within about 8% of the nominal values. A theoretical and experimental analysis of the effect of the sample arm fibre on determination of optical axis orientation using a proposed definition based on the orientation of the eigenpolarization ellipse experimentally confirms that this algorithm only works correctly for special settings of the sample arm fibre. A proposed algorithm based on the angle between Stokes vectors on the Poincaré sphere is confirmed to work for all settings of the sample arm fibre. A calibration procedure is proposed to remove the sign ambiguity of the measured orientation and was confirmed experimentally by using the QWP.

  18. Optic axis determination by fibre-based polarization-sensitive swept-source optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lu Zenghai; Kasaragod, Deepa K; Matcher, Stephen J, E-mail: z.lu@sheffield.ac.uk, E-mail: s.j.matcher@sheffield.ac.uk [Department of Materials Science and Engineering, Kroto Research Institute, University of Sheffield, North Campus, Broad Lane, Sheffield, S3 7HQ (United Kingdom)

    2011-02-21

    We describe a fibre-based variable-incidence angle (VIA) polarization-sensitive swept-source optical coherence tomography (PS-SS-OCT) system to determine the 3D optical axis of birefringent biological tissues. Single-plane VIA-PS-OCT is also explored which requires measurement of the absolute fast-axis orientation. A state-of-the-art PS-SS-OCT system with some improvements both in hardware and software was used to determine the apparent optical birefringence of equine tendon for a number of different illumination directions. Polar and azimuthal angles of cut equine tendon were produced by the VIA method and compared with the nominal values. A quarter waveplate (QWP) and equine tendon were used as test targets to validate the fast-axis measurements using the system. Polar and azimuthal angles of cut equine tendon broadly agreed with the expected values within about 8% of the nominal values. A theoretical and experimental analysis of the effect of the sample arm fibre on determination of optical axis orientation using a proposed definition based on the orientation of the eigenpolarization ellipse experimentally confirms that this algorithm only works correctly for special settings of the sample arm fibre. A proposed algorithm based on the angle between Stokes vectors on the Poincare sphere is confirmed to work for all settings of the sample arm fibre. A calibration procedure is proposed to remove the sign ambiguity of the measured orientation and was confirmed experimentally by using the QWP.

  19. Scintillation Particle Detectors Based on Plastic Optical Fibres and Microfluidics

    CERN Document Server

    Mapelli, Alessandro; Renaud, Philippe

    2011-01-01

    This thesis presents the design, development, and experimental validation of two types of scintillation particle detectors with high spatial resolution. The first one is based on the well established scintillating fibre technology. It will complement the ATLAS (A Toroidal Large ApparatuS) detector at the CERN Large Hadron Collider (LHC). The second detector consists in a microfabricated device used to demonstrate the principle of operation of a novel type of scintillation detector based on microfluidics. The first part of the thesis presents the work performed on a scintillating fibre tracking system for the ATLAS experiment. It will measure the trajectory of protons elastically scattered at very small angles to determine the absolute luminosity of the CERN LHC collider at the ATLAS interaction point. The luminosity of an accelerator characterizes its performance. It is a process-independent parameter that is completely determined by the properties of the colliding beams and it relates the cross section of a ...

  20. POLARISATION PRESERVING OPTICAL FIBRE

    DEFF Research Database (Denmark)

    2000-01-01

    A micro-structured optical fibre having a cladding comprising a number of elements having a non-circular cross-section. Each element has at least one part extending outside a circle having the same cross-sectional area as the element. These extending parts are directed in the same direction....... This cladding structure provides polarisation preserving properties to the optical fibre. Optical fibres using this technology may have claddings with elements placed non-periodically as well as in a two-dimensional periodic lattice - such as cladding providing Photonic Band Gap (PBG) effects....

  1. All-optical switching based on optical fibre long period gratings modified bacteriorhodopsin

    Science.gov (United States)

    Korposh, S.; James, S.; Partridge, M.; Sichka, M.; Tatam, R.

    2018-05-01

    All-optical switching using an optical fibre long-period gating (LPG) modified with bacteriorhodopsin (bR) is demonstrated. The switching process is based on the photo-induced RI change of bR, which in turn changes the phase matching conditions of the mode coupling by the LPG, leading to modulation of the propagating light. The effect was studied with an LPG immersed into a bR solution and with LPGs coated with the bR films, deposited onto the LPGs using the layer-by-layer electrostatic self-assembly (LbL) method. The dependence of the all-optical switching efficiency upon the concentration of the bR solution and on the grating period of the LPG was also studied. In addition, an in-fibre Mach-Zehnder interferometer (MZI) composed of a cascaded LPG pair separated by 30 mm and modified with bR was used to enhance the wavelength range of all-optical switching. The switching wavelength is determined by the grating period of the LPG. Switching efficiencies of 16% and 35% were observed when an LPG and an MZI were immersed into bR solutions, respectively. The switching time for devices coated with bR-films was within 1 s, 10 times faster than that observed for devices immersed into bR solution.

  2. Performances of different metals in optical fibre-based surface ...

    Indian Academy of Sciences (India)

    For the past few years, intense investigations were done on various sensing techniques, which may be employed for ... vector parallel to the incident plane) coincide with those of the surface plasmon wave, this light resonantly .... critical angle of the fibre and ncl is the refractive index of the cladding of the fibre. 2.6 Sensitivity ...

  3. Optical Fibre Bundle

    CERN Multimedia

    These are sample fibre optic cables which are used for networking. Optical fibers are widely used in fiber-optic communications, where they permit transmission over longer distances and at higher bandwidths (data rates) than wire cables. Fibers are used instead of metal wires because signals travel along them with less loss and are also immune to electromagnetic interference. This is useful for somewhere like CERN where magnets with their highly powerful magnetic fields could pose a problem.

  4. Novel Highly Sensitive Protein Sensors Based on Tapered Optical Fibres Modified with Au-Based Nanocoatings

    Directory of Open Access Journals (Sweden)

    Aitor Urrutia

    2016-01-01

    Full Text Available Novel protein sensors based on tapered optical fibres modified with Au coatings deposited using two different procedures are proposed. Au-based coatings are deposited onto a nonadiabatic tapered optical fibre using (i a novel facile method composed of layer-by-layer deposition consisting of polycation (poly(allylamine hydrochloride, PAH and negatively charged SiO2 nanoparticles (NPs followed by the deposition of the charged Au NPs and (ii the sputtering technique. The Au NPs and Au thin film surfaces are then modified with biotin in order to bind streptavidin (SV molecules and detect them. The sensing principle is based on the sensitivity of the transmission spectrum of the device to changes in the refractive index of the coatings induced by the SV binding to the biotin. Both sensors showed high sensitivity to SV, with the lowest measured concentration levels below 2.5 nM. The calculated binding constant for the biotin-SV pair was 2.2×10-11 M−1 when a tapered fibre modified with the LbL method was used, with a limit of detection (LoD of 271 pM. The sensor formed using sputtering had a binding constant of 1.01×10-10 M−1 with a LoD of 806 pM. These new structures and their simple fabrication technique could be used to develop other biosensors.

  5. Fibre optic communication key devices

    CERN Document Server

    Grote, Norbert

    2017-01-01

    The book gives an in-depth description of key devices of current and next generation fibre optic communication networks. Devices treated include semiconductor lasers, optical amplifiers, modulators, wavelength filters and other passives, detectors, all-optical switches, but relevant properties of optical fibres and network aspects are included as well. The presentations include the physical principles underlying the various devices, technologies used for their realization, typical performance characteristics and limitations, but development trends towards more advanced components are also illustrated. This new edition of a successful book was expanded and updated extensively. The new edition covers among others lasers for optical communication, optical switches, hybrid integration, monolithic integration and silicon photonics. The main focus is on Indium phosphide-based structures but silicon photonics is included as well. The book covers relevant principles, state-of-the-art implementations, status of curren...

  6. A large core polymer optical fibre sensor for x-ray dosimetry based on luminescence occurring in the cladding

    NARCIS (Netherlands)

    Fitzpatrick, C.; O'Donoghue, C.; Schöbel, J.; Bastiaens, Hubertus M.J.; van der Slot, Petrus J.M.; Lewis, E.; Pendrill, D.

    2004-01-01

    An optical fibre sensor for short pulse duration x-ray dosimetry is presented. The sensor is based on luminescence generated in the cladding of a 1 mm core diameter polymer optical fibre which has been doped with a radioluminescent phosphor. On interaction with x-rays, this phosphor emits visible

  7. Development of evanescent wave absorbance-based fibre-optic ...

    Indian Academy of Sciences (India)

    ... the fibre, the localized surface plasmon resonance of noble metal nanoparticles at visible wavelength was exploited as a sensing medium for the biochemical reactions. Our systematic studies in this regard presented in this communication may bring the excitement for developing the waterborne pathogen detection device ...

  8. Fabrication of silicon based glass fibres for optical communication

    Indian Academy of Sciences (India)

    Unknown

    creasing demand of fibre in diverse application areas. Various processes are being modified such as preform making, melting process, melting environment, homoge- nization/fining, and reactive atmosphere processing. (France Paul et al 1990). Hermetic carbon coating has been shown to be effective barrier for water and ...

  9. Fibre-optic metadevice for all-optical signal modulation based on coherent absorption.

    Science.gov (United States)

    Xomalis, Angelos; Demirtzioglou, Iosif; Plum, Eric; Jung, Yongmin; Nalla, Venkatram; Lacava, Cosimo; MacDonald, Kevin F; Petropoulos, Periklis; Richardson, David J; Zheludev, Nikolay I

    2018-01-12

    Recently, coherent control of the optical response of thin films in standing waves has attracted considerable attention, ranging from applications in excitation-selective spectroscopy and nonlinear optics to all-optical image processing. Here, we show that integration of metamaterial and optical fibre technologies allows the use of coherently controlled absorption in a fully fiberized and packaged switching metadevice. With this metadevice, which controls light with light in a nanoscale plasmonic metamaterial film on an optical fibre tip, we provide proof-of-principle demonstrations of logical functions XOR, NOT and AND that are performed within a coherent fibre network at wavelengths between 1530 and 1565 nm. The metadevice has been tested at up to 40 gigabits per second and sub-milliwatt power levels. Since coherent absorption can operate at the single-photon level and with 100 THz bandwidth, we argue that the demonstrated all-optical switch concept has potential applications in coherent and quantum information networks.

  10. Microstructured Optical Fibres

    DEFF Research Database (Denmark)

    1999-01-01

    complete PBGs, which reflects light incident from air or vacuum. Such structures may be used as cladding structures in optical fibres, where light is confined and thereby guided in a hollow core region. In addition, the present invention relates to designs for ultra low-loss PBG waveguiding structures......The present invention relates to a new class of optical waveguides, in which waveguiding along one or more core regions is obtained through the application of the Photonic Bandgap (PBG) effect. The invention further relates to optimised two-dimensional lattice structures capable of providing...

  11. Recent advances in poled optical fibres

    DEFF Research Database (Denmark)

    Pruneri, V.; Margulis, W.; Myrén, N.

    2005-01-01

    A second-order nonlinearity can be induced in optical fibres through poling. We describe accomplishments of the EU project GLAMOROUS in making low-cost high performance electrooptic and nonlinear optical fibre- and waveguide-based components. In particular a comparison with more traditional...

  12. A review of materials engineering in silicon-based optical fibres

    Science.gov (United States)

    Healy, Noel; Gibson, Ursula; Peacock, Anna C.

    2018-02-01

    Semiconductor optical fibre technologies have grown rapidly in the last decade and there are now a range of production and post-processing techniques that allow for a vast degree of control over the core material's optoelectronic properties. These methodologies and the unique optical fibre geometry provide an exciting platform for materials engineering and fibres can now be produced with single crystal cores, low optical losses, tunable strain, and inscribable phase composition. This review discusses the state-of-the-art regarding the production of silicon optical fibres in amorphous and crystalline form and then looks at the post-processing techniques and the improved material quality and new functionality that they afford.

  13. Strain sensor based on gourd-shaped single-mode-multimode-single-mode hybrid optical fibre structure.

    Science.gov (United States)

    Tian, Ke; Farrell, Gerald; Wang, Xianfan; Yang, Wenlei; Xin, Yifan; Liang, Haidong; Lewis, Elfed; Wang, Pengfei

    2017-08-07

    A fibre-optic strain sensor based on a gourd-shaped joint multimode fibre (MMF) sandwiched between two single-mode fibres (SMFs) is described both theoretically and experimentally. The cladding layers of the two MMFs are reshaped to form a hemisphere using an electrical arc method and spliced together, yielding the required gourd shape. The gourd-shaped section forms a Fabry-Perot cavity between the ends of two adjacent but non-contacting multimode fibres' core. The effectiveness of the multimode interference based on the Fabry-Perot interferometer (FPI) formed within the multimode inter-fibre section is greatly improved resulting in an experimentally determined strain sensitivity of -2.60 pm/με over the range 0-1000 με. The sensing characteristics for temperature and humidity of this optical fibre strain sensor are also investigated.

  14. Fabrication of polymer-based reflowed microlenses on optical fibre ...

    Indian Academy of Sciences (India)

    Permanent link: http://www.ias.ac.in/article/fulltext/sadh/034/04/0607-0613. Keywords. Microlens; thermal reflow; optical fibre; focal length control; differential coating, polymer optical MEMS. Abstract. Thermal reflow of polymer to generate spherical profile has been used to fabricate microlenses in this paper. A simple model ...

  15. Design of a Sensor Based on Plastic Optical Fibre (POF to Measure Fluid Flow and Turbidity

    Directory of Open Access Journals (Sweden)

    Joseba Zubia

    2009-05-01

    Full Text Available Although many optical fibre applications are based on their capacity to transmit optical signals with low losses, it can also be desirable for the optical fibre to be strongly affected by a certain physical parameter in the environment. In this way, it can be used as a sensor for this parameter. There are many strong arguments for the use of POFs as sensors. In addition to being easy to handle and low cost, they demonstrate advantages common to all multimode optical fibres. These specifically include flexibility, small size, good electromagnetic compatibility behaviour, and in general, the possibility of measuring any phenomenon without physically interacting with it. In this paper, a sensor based on POF is designed and analysed with the aim of measuring the volume and turbidity of a low viscosity fluid, in this case water, as it passes through a pipe. A comparative study with a commercial sensor is provided to validate the proven flow measurement. Likewise, turbidity is measured using different colour dyes. Finally, this paper will present the most significant results and conclusions from all the tests which are carried out.

  16. Controlled core-to-core photo-polymerisation - fabrication of an optical fibre-based pH sensor.

    Science.gov (United States)

    Mohamad, Fuad; Tanner, Michael G; Choudhury, Debaditya; Choudhary, Tushar R; Wood, Harry A C; Harrington, Kerrianne; Bradley, Mark

    2017-09-25

    The fabrication of fluorescence-based pH sensors, embedded into etched pits of an optical fibre via highly controllable and spatially selective photo-polymerisation is described and the sensors validated.

  17. Fabrication of polymer-based reflowed microlenses on optical fibre ...

    Indian Academy of Sciences (India)

    A biomedical application of such combination of microlenses is endoscopy where the lenses of varying diameter and equal focal length are needed on top of optical fibre bundles to provide independent function of illumination and imaging. This paper incorporates the differential thickness technique to show a micro ...

  18. Optical fibre dosemeter systems for clinical applications based on radioluminescence and optically stimulated luminescence from Al2O3:C

    DEFF Research Database (Denmark)

    Marckmann, C.J.; Andersen, C.E.; Aznar, M.C.

    2006-01-01

    for making ultra-small dosemeter probes that can easily be placed inside patients in radiation treatment. These probes have shown excellent properties in both head and neck intensity-modulated radiation therapy treatment and in mammography. The dose-response of the OSL signal for the new optical fibre......Optical fibre dosemeter systems based on radioluminescence and optically stimulated luminescence (OSL) from carbon-doped aluminium oxide (Al2O3:C) crystals were developed for in vivo real-time dose rate and absorbed dose measurements in radiotherapy and mammography. A technique was also developed...... dosemeter system showed a repeatability within 0.15% at a dose level of 60 mGy when integrated over 100 s. The temperature dependence in the range 0-45 degrees C showed a reproducibility within 1.3% when the OSL signal was integrated over 100 s....

  19. Fabrication of polymer-based reflowed microlenses on optical fibre ...

    Indian Academy of Sciences (India)

    Abstract. Thermal reflow of polymer to generate spherical profile has been used to fabricate microlenses in this paper. A simple model based on the volume conservation (before and after reflow) and geometrical consideration of lens profile, shows that the focal length of the microlens produced by reflow technique is a.

  20. A fibre optic displacement sensor

    OpenAIRE

    Sohlström, Hans; Holm, Ulf

    1982-01-01

    Fibre optics is beginning to find use for sensing purposes. Fibre optic sensors have many interesting features, e.g., their immunity to interference from electromagnetic fields. The paper briefly discusses different sensor principles. A displacement sensor using multimode, step index fibres is desccribed. Measurement data showing a resolution of 0.05 nm/sqrt(Hz) in a 150 µm linear range is given. In this sensor, the light coupling between two fibre ends varies with the position of a movable ...

  1. Optical Fibre Pressure Sensors in Medical Applications

    Directory of Open Access Journals (Sweden)

    Sven Poeggel

    2015-07-01

    Full Text Available This article is focused on reviewing the current state-of-the-art of optical fibre pressure sensors for medical applications. Optical fibres have inherent advantages due to their small size, immunity to electromagnetic interferences and their suitability for remote monitoring and multiplexing. The small dimensions of optical fibre-based pressure sensors, together with being lightweight and flexible, mean that they are minimally invasive for many medical applications and, thus, particularly suited to in vivo measurement. This means that the sensor can be placed directly inside a patient, e.g., for urodynamic and cardiovascular assessment. This paper presents an overview of the recent developments in optical fibre-based pressure measurements with particular reference to these application areas.

  2. Optical Fibre Pressure Sensors in Medical Applications.

    Science.gov (United States)

    Poeggel, Sven; Tosi, Daniele; Duraibabu, DineshBabu; Leen, Gabriel; McGrath, Deirdre; Lewis, Elfed

    2015-07-15

    This article is focused on reviewing the current state-of-the-art of optical fibre pressure sensors for medical applications. Optical fibres have inherent advantages due to their small size, immunity to electromagnetic interferences and their suitability for remote monitoring and multiplexing. The small dimensions of optical fibre-based pressure sensors, together with being lightweight and flexible, mean that they are minimally invasive for many medical applications and, thus, particularly suited to in vivo measurement. This means that the sensor can be placed directly inside a patient, e.g., for urodynamic and cardiovascular assessment. This paper presents an overview of the recent developments in optical fibre-based pressure measurements with particular reference to these application areas.

  3. In-situ monitoring of ammonia gas using an optical fibre based approach

    Science.gov (United States)

    Dooly, G.; Manap, H.; O'Keeffe, S.; Lewis, E.

    2011-08-01

    An optical fibre sensor for the monitoring of low level atmospheric ammonia concentrations is presented. The measuring technique employed is based on a differential optical absorption approach, rather than a semiconductor based technique which is generally exploited within comparable commercially available products. The sensor described herein demonstrates vast improvements in terms of sensitivity, selectivity and lifespan over ammonia sensors currently available commercially. Extensive laboratory-based experimental tests demonstrate the sensor's ability to monitor concentrations as low as 1ppm without any notable cross-sensitivity issues to atmospheric gases such as nitrogen, oxygen and carbon dioxide. Furthermore, in-situ experimental tests within an agricultural cattle enclosure demonstrate sensor's suitability to environments where low concentration monitoring of ammonia over extended periods of time is necessary.

  4. In-situ monitoring of ammonia gas using an optical fibre based approach

    International Nuclear Information System (INIS)

    Dooly, G; Manap, H; O'Keeffe, S; Lewis, E

    2011-01-01

    An optical fibre sensor for the monitoring of low level atmospheric ammonia concentrations is presented. The measuring technique employed is based on a differential optical absorption approach, rather than a semiconductor based technique which is generally exploited within comparable commercially available products. The sensor described herein demonstrates vast improvements in terms of sensitivity, selectivity and lifespan over ammonia sensors currently available commercially. Extensive laboratory-based experimental tests demonstrate the sensor's ability to monitor concentrations as low as 1ppm without any notable cross-sensitivity issues to atmospheric gases such as nitrogen, oxygen and carbon dioxide. Furthermore, in-situ experimental tests within an agricultural cattle enclosure demonstrate sensor's suitability to environments where low concentration monitoring of ammonia over extended periods of time is necessary.

  5. Spider silk: a novel optical fibre for biochemical sensing

    OpenAIRE

    Hey Tow, Kenny; Chow, Desmond; Vollrath, Fritz; Dicaire, Isabelle; Gheysens, Tom; Thévenaz, Luc

    2015-01-01

    Whilst being thoroughly used in the textile industry and biomedical sector, silk has not yet been exploited for fibre optics-based sensing although silk fibres directly obtained from spiders can guide light and have shown early promises to being sensitive to some solvents. In this communication, a pioneering optical fibre sensor based on spider silk is reported, demonstrating for the first time the use of spider silk as an optical fibre sensor to detect polar solvents such as water, ammonia a...

  6. A fibre optic humidity sensor based on a long-period fibre grating coated with a thin film of SiO2 nanospheres

    Science.gov (United States)

    Viegas, D.; Goicoechea, J.; Corres, J. M.; Santos, J. L.; Ferreira, L. A.; Araújo, F. M.; Matias, I. R.

    2009-03-01

    A novel sensing configuration for measuring humidity based on a long-period fibre grating coated with a thin film of silica nanospheres is proposed. The polymeric overlay is deposited on the grating using the electrostatic self-assembly technique. This thin film changes its optical properties when exposed to different humidity levels that translate into a shift of the resonance wavelength of the fibre grating. Wavelength shifts up to 12 nm in a relative humidity range from 20% to 80% are reported, and it is further demonstrated that such humidity sensitivity has negligible thermal dependence.

  7. Silica-based optical fibres with refractive-index profiles tailored in a region of 1.46-1.62 for fibre-optic chemical detection

    Czech Academy of Sciences Publication Activity Database

    Kašík, Ivan; Matějec, Vlastimil; Chomát, Miroslav; Hayer, Miloš; Mrázek, Jan; Skokánková, Jana

    2005-01-01

    Roč. 107, č. 1 (2005), s. 93-97 ISSN 0925-4005. [European Conference on Optical Chemical Sensors and Biosensors EUROPT(R)ODE /7./. Madrid, 04.04.2004-07.04.2004] R&D Projects: GA ČR(CZ) GA102/02/0780 Institutional research plan: CEZ:AV0Z20670512 Keywords : optical fibres * optical sensors * refractive index Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.646, year: 2005

  8. Design of microstructured optical fibres made from highly nonlinear glasses for FWM-based telecom applications

    Czech Academy of Sciences Publication Activity Database

    Kaňka, Jiří

    2008-01-01

    Roč. 16, č. 25 (2008), s. 20395-20408 ISSN 1094-4087 R&D Projects: GA MŠk 1P05OC002; GA MŠk OE08021 Institutional research plan: CEZ:AV0Z20670512 Keywords : Nonlinear optics * Highly nonlinear fibres * Fibre design Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.880, year: 2008

  9. Reflection-based fibre-optic refractive index sensor using surface plasmon resonance

    Czech Academy of Sciences Publication Activity Database

    Hlubina, P.; Kadulová, M.; Ciprian, D.; Sobota, Jaroslav

    2014-01-01

    Roč. 9, August 19 (2014), 14033:1-5 ISSN 1990-2573 R&D Projects: GA MŠk(CZ) LO1212 Keywords : surface plasmon resonance * fibre -optic sensor * spectral interrogation technique * aqueous solutions of ethanol * refractive index Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.231, year: 2014

  10. Fibre Optics In Coal Mining

    Science.gov (United States)

    Cooper, Paul

    1984-08-01

    Coal mines have a number of unique problems which affect the use of fibre optic technology. These include a potentially explosive atmosphere due to the evolution of methane from coal, and a dirty environment with no cleaning facilities readily available. Equipment being developed by MRDE to allow the exploitation of optical fibres underground includes: A hybrid electrical/fibre optic connector for the flexible power trailing cable of the coal-face shearer; An Intrinsically Safe (IS) pulsed laser transmitter using Frequency Shift Key (FSK) data modulation; An IS Avalanche Photo Diode Receiver suitable for pulsed & continuous wave optical signals; A mine shaft and roadway cable/ connector system incorporating low loss butt-splices and preterminated demountable connectors.

  11. Fibre Optic Communication Key Devices

    CERN Document Server

    Grote, Norbert

    2012-01-01

    The book gives an in-depth description of the key devices of current and next generation fibre optic communication networks. In particular, the book covers devices such as semiconductor lasers, optical amplifiers, modulators, wavelength filters, and detectors but the relevant properties of optical fibres as well. The presentations include the physical principles underlying the various devices, the technologies used for the realization of the different devices, typical performance characteristics and limitations, and development trends towards more advanced components are also illustrated. Thus the scope of the book spans relevant principles, state-of-the-art implementations, the status of current research and expected future components.

  12. Fibre-optic communications

    CERN Document Server

    Lecoy, Pierre

    2010-01-01

    This book describes in a comprehensive manner the components and systems of fiber optic communications and networks. The first section explains the theory of multimode and single-mode fibers, then the technological features, including manufacturing, cabling, and connecting. The second section describes the various components (passive and active optical components, integrated optics, opto-electronic transmitters and receivers, and optical amplifiers) used in fiber optic systems. Finally, the optical transmission system design is explained, and applications to optical networks and fiber optic se

  13. Thermal insensitive optical liquid level sensor based on excessively tilted fibre Bragg grating

    OpenAIRE

    Mou, Chengbo; Zhou, Kaiming; Zhang, Lin; Bennion, Ian

    2008-01-01

    We demonstrate a liquid level sensor based on the surrounding medium refractive index (SRI) sensing using of an excessively tilted fibre Bragg grating (ETFBG). The sensor has low thermal cross sensitivity and high SRI responsivity.

  14. Cool application for Optical Fibres

    CERN Multimedia

    2001-01-01

    In a new first for CERN, optical fibres have been put on test to measure very low temperatures. If these tests prove successful, this new technology could lead to important cost-saving changes in the way the temperatures of superconducting magnets are measured. There was excitement in the air last March when the team led by Walter Scandale and Luc Thévenaz tested very low temperature measurement using optical fibres. This spring in CERN's Cryogenics lab an idea was put to the test as a new kind of low-temperature thermometry using optical fibres was tested down to 2 Kelvin (around 300 degrees below room temperature), and the first results are looking good. Optical fibres are well known for their ability to carry large amounts of data around the world, but it is less well known that they can be used for measuring temperatures. The intuition that they might be able to measure very low temperatures - such as those of the LHC magnets - came to the attention of CERN's Walter Scandale at the Optical Fi...

  15. Chemical detection of liquid media with a refractrometric sensor based a multimode optical fibre

    Czech Academy of Sciences Publication Activity Database

    Cherif, K.; Hleli, S.; Abdelghani, A.; Jaffrezic-Renault, N.; Matějec, Vlastimil

    2002-01-01

    Roč. 2, č. 6 (2002), s. 195-204 ISSN 1424-8220 R&D Projects: GA ČR GA102/02/0780; GA AV ČR KSK2067107 Projekt 07/01:4074 Institutional research plan: CEZ:AV0Z2067918 Keywords : optical fibres * refractometer * optical sensor s Subject RIV: JB - Sensor s, Measurment, Regulation Impact factor: 0.990, year: 2002 http://www.mdpi.net/ sensor s

  16. Nonlinear fibre optics overview

    DEFF Research Database (Denmark)

    Travers, J. C.; Frosz, Michael Henoch; Dudley, J. M.

    2010-01-01

    The optical fiber based supercontinuum source has recently become a significant scientific and commercial success, with applications ranging from frequency comb production to advanced medical imaging. This one-of-a-kind book explains the theory of fiber supercontinuum broadening, describes...... the diverse operational regimes and indicates principal areas of applications, making it a very important guide for researchers and graduate students. With contributions from major figures and groups who have pioneered research in this field, the book describes the historical development of the subject...

  17. Nonlinear microstructured polymer optical fibres

    DEFF Research Database (Denmark)

    Frosz, Michael Henoch

    is potentially the case for microstructured polymer optical fibres (mPOFs). Another advantage is that polymer materials have a higher biocompatibility than silica, meaning that it is easier to bond certain types of biosensor materials to a polymer surface than to silica. As with silica PCFs, it is difficult...

  18. Flow diagnostics using fibre optics

    Indian Academy of Sciences (India)

    high enthalpy, high speed flows and in combustion chambers, rocket exhausts etc. 3. Aerodynamic load measurements at hypersonic speeds using internally mounted fibre-optic balance system. 3.1 The IISc hypersonic wind tunnel. The IISc hypersonic wind tunnel is of the pressure-vacuum type with an open jet test section.

  19. Sensitivity enhancement using annealed polymer optical fibre based sensors for pressure sensing applications

    DEFF Research Database (Denmark)

    Pospori, A.; Marques, C. A. F.; Saez-Rodriguez, D.

    2016-01-01

    Thermal annealing can be used to induce a permanent negative Bragg wavelength shift for polymer fibre grating sensors and it was originally used for multiplexing purposes. Recently, researchers showed that annealing can also provide additional benefits, such as strain and humidity sensitivity...... enhancement and augmented temperature operational range. The annealing process can change both the optical and mechanical properties of the fibre. In this paper, the annealing effects on the stress and force sensitivities of PMMA fibre Bragg grating sensors are investigated. The incentive...... for that investigation was an unexpected behaviour observed in an array of sensors which were used for liquid level monitoring. One sensor exhibited much lower pressure sensitivity and that was the only one that was not annealed. To further investigate the phenomenon, additional sensors were photo...

  20. Optical Fibres in the Modeling of Translucent Concrete Blocks

    OpenAIRE

    M.N.V.Padma Bhushan, D.Johnson, Md. Afzal Basheer Pasha And Ms. K. Prasanthi

    2013-01-01

    Translucent concrete is a concrete based material with light-transmissive properties, obtained due to embedded light optical elements like Optical fibers in it. Light is conducted through the stone from one end to the other. This results into a certain light pattern on the other surface, depending on the fibre structure. Optical fibres transmit light so effectively that there is virtually no loss of light conducted through the fibres. Our paper deals with the modelling of such translucent or ...

  1. A fibre optic oxygen sensor for monitoring of human breathing

    Science.gov (United States)

    Chen, Rongsheng; Farmery, Andrew D.; Chen, Rui; Hahn, Clive E. W.

    2011-11-01

    A reliable and cost effective fibre optic oxygen sensor for monitoring of human breathing has been developed using a normal 200μm silica core/silica cladding optical fibre and a polymer sensing matrix. The fibre optic oxygen sensor is based on the fluorescence quenching of a fluorophore by oxygen. The sensing matrix, containing immobilized Pt(II) complexes, was coated at the end of the silica core/silica cladding optical fibre. The sensitivity and time response of the sensor were evaluated using the method of luminescence lifetime measurement. The polymer substrate influence on the time response of the sensor was improved by using a fibre taper design, and the response time of the optimized sensor was less than 200ms. This silica fibre based optic oxygen sensor is suitable for monitoring of patient breathing in intensive care unit in terms of safety and low cost.

  2. Fibre optic cable in the nuclear industry

    International Nuclear Information System (INIS)

    Roberts, Berwyn

    1987-01-01

    The uses of optical fibre cables to transmit light signals include medical applications and telecommunications. In the nuclear industry the applications include process control and monitoring, conventional datacoms, security fencing and sensors. Time division multiplexing is described and currently available fibre optic multipexers are listed and explained. Single and multimode fibres are mentioned. Fibre optics are also used in cryogenics, to monitor the integrity of the storage vessels for cryogenic liquids. The uses of fibre optics at Hartlepool, Heysham I and Torness are mentioned in particular. (UK)

  3. Flow diagnostics using fibre optics

    Indian Academy of Sciences (India)

    a finely machined calibration body as shown in figure 10. The entire loading setup was placed under water in a fish tank measuring 3 × 1·5 × 1·25 ft as shown in figure 11. Prede- termined loads were applied to the balance and the resulting calibration curves are shown in figure 12a & b. The fibre-optic processor was set at ...

  4. Standard Fibre Optic Ring LANs

    Science.gov (United States)

    Beale, N. C. L.

    1985-08-01

    The paper begins with a reminder of the particular need for standards in LANs. We then describe the requirements of High Integrity LANs. Current developments in LAN standards are then outlined. It is argued that the requirements of industrial LANs lead ideally to reconfiguring fibre optic rings, for which there are two major emerging standards. These two (IEEE 802.5 and ANSI FDDI) and the Cambridge Ring are discussed and compared. One implementation - the HILAN is discussed.

  5. Optical fibre gratings as tools for chemical and biochemical sensing.

    Science.gov (United States)

    Baldini, F; Brenci, M; Chiavaioli, F; Giannetti, A; Trono, C

    2012-01-01

    Optical fibre gratings have recently been suggested as optical platforms for chemical and biochemical sensing. On the basis of the measurement of refractive index changes induced by a chemical and biochemical interaction in the transmission spectrum along the fibres, they are proposed as a possible alternative to the other label-free optical approaches, such as surface plasmon resonance and optical resonators. The combination of the use of optical fibres with the fact that the signal modulation is spectrally encoded offers multiplexing and remote measurement capabilities which the other technology platforms are not able to or can hardly offer. The fundamentals of the different types of optical fibre gratings are described and the performances of the chemical and biochemical sensors based on this approach are reviewed. Advantages and limitations of optical fibre gratings are considered, with a look at new perspectives for their utilization in the field.

  6. Megavoltage X-Ray Imaging Based on Cerenkov Effect: A New Application of Optical Fibres to Radiation Therapy

    Directory of Open Access Journals (Sweden)

    A. Teymurazyan

    2012-01-01

    Full Text Available A Monte Carlo simulation was used to study imaging and dosimetric characteristics of a novel design of megavoltage (MV X-ray detectors for radiotherapy applications. The new design uses Cerenkov effect to convert X-ray energy absorbed in optical fibres into light for MV X-ray imaging. The proposed detector consists of a matrix of optical fibres aligned with the incident X rays and coupled to an active matrix flat-panel imager (AMFPI for image readout. Properties, such as modulation transfer function, detection quantum efficiency (DQE, and energy response of the detector, were investigated. It has been shown that the proposed detector can have a zero-frequency DQE more than an order of magnitude higher than that of current electronic portal imaging device (EPID systems and yet a spatial resolution comparable to that of video-based EPIDs. The proposed detector is also less sensitive to scattered X rays from patients than current EPIDs.

  7. EDITORIAL: Optical Fibre Sensors 18 (OFS-18)

    Science.gov (United States)

    Jones, Julian D. C.; Tatam, Ralph P.

    2007-10-01

    The International Conference on Optical Fibre Sensors (OFS-18) was held in October 2006 in Cancún, Mexico, under the general chairmanship of Dr Alexis Mendez (MCH Engineering LLC, USA) and Dr Fernando Mendoza (Centro de Investigaciones en Optica, Mexico). 'OFS', as it has become known, is firmly established as the leading international conference for the optical fibre sensor community. Since its inception, in London in 1983, and under the leadership of an international steering committee independent of any learned society or professional institution, it has been held approximately every eighteen months. The venue nominally rotates from Europe, to the Americas, and thence to Asia and the Pacific. OFS-18 demonstrated the continuing vigour of the community, with some 250 papers presented, plus two workshops, with attendance as international as ever. In recent years, it has become a tradition to publish a post-conference special issue in the journal Measurement Science and Technology, and these special issues offer a representative sample of the current status of the field. In the nearly 25 years since OFS began, many of the early ideas and laboratory-based proof-of-principle experiments have led to highly developed instrumentation systems, and to successful commercial products. Perhaps the most mature of all of these technologies is the optical fibre gyroscope, with the fibre hydrophone a close second—originally developed for defence applications for which it is now established, but with increasing relevance to the oil and gas industry; electromagnetic sensors based on the Faraday and electro-optic effects are of growing significance in the power generation and distribution industry; whilst in-fibre grating-based sensors occupy an expanding niche in structural monitoring, especially in civil engineering. It is therefore appropriate that the first day of OFS was devoted to workshops on structural health monitoring, and to commemorate the 30th anniversary of the

  8. Fibre optic power meter calibration uncertainties

    CSIR Research Space (South Africa)

    Nel, M

    2010-06-01

    Full Text Available The method to empirically quantify the effect that flexing (movement) of the fibre has on the output power was determined by connecting an optical fibre to a power meter head and performing controlled movements of the head (displacements and rotations..., and with their optical axes roughly parallel to one another to reduce the effect of fibre flexing when interchanging from one detector head to another. Excessive flexing and moving of the fibre can cause differences in the radiant power emerging from the fibre...

  9. Optical Fibre NO₂ Sensor Based on Lutetium Bisphthalocyanine in a Mesoporous Silica Matrix.

    Science.gov (United States)

    Debliquy, Marc; Lahem, Driss; Bueno-Martinez, Antonio; Caucheteur, Christophe; Bouvet, Marcel; Recloux, Isaline; Raskin, Jean-Pierre; Olivier, Marie-Georges

    2018-03-01

    In this article, we describe a NO₂ sensor consisting of a coating based on lutetium bisphthalocyanine (LuPc₂) in mesoporous silica. The sensor exploits the absorption spectrum change of this material which strongly and reversibly decreases in contact with NO₂. NO₂ is measured by following the amplitude change in the reflected spectrum of the coating deposited on the tip of a silica fibre. As diffusion of NO₂ in LuPc₂ is slow, the response time could be slow. To reduce it, the active molecules are dispersed in a mesoporous silica matrix deposited by a sol-gel process (Evaporation Induced Self Assembly) avoiding the formation of large crystals. Doing so, the response is fairly fast. As the recovery is slow at room temperature, the recovery time is reduced by exposure to UV light at 365 nm. This UV light is directly introduced in the fibre yielding a practical sensor sensitive to NO₂ in the ppm range suitable for pollution monitoring.

  10. A Simple and Sensitive Flow Injection Optical Fibre Biosensor Based on Immobilised Enzyme for Monitoring of Pesticides

    Directory of Open Access Journals (Sweden)

    B. Kuswandi

    2007-02-01

    Full Text Available A simple and sensitive flow injection optical fibre biosensor based on immobilised enzyme for monitoring of pesticides has been developed. The optical fibre biosensor consists of immobilised acethylcholinesterase (AChE coupled with commercial pH indicator strip. The biosensing process involves the inhibition of AChE by pesticides, where the pH change has been monitored via a pH indicator strip as an optical transducer. The enzyme as a bio-recognition element has been immobilised onto solid-support material (i.e. covalently bond onto preactivated isothiocyanate glass, ICG and then packed in a thermostatic bioreactor connected to the flow-cell that contains pH indicator strip. In the presence of a constant AChE, a colour of the pH layer change and the measured reflected signal could be related to the pesticide concentration in the sample solution. The performance of the flow injection optical biosensor system has been optimized, including chemical and physical parameters. The calibration plot of the inhibition for the determination of organophosphate pesticides (dimethoate and carbamate pesticide (propoxur were in the range of 50 to 1000 µg/l for dimethoate and 10 to 100 µg/l for propoxur. The biosensor allows lower detection limits, calculated at I10%, for propoxur (4.9 µg/l than for dimethoate (24 µg/l, and produces highly reproducible response (RSD<1.5% and readily reversible in the case of carbamate pesticide. While in the case of organophosphate, the regeneration has been possible by treatment with hydroxylamine solution. The flow injection optical fibre biosensor system has been successfully applied for the determination of pesticides in the real water samples.

  11. Optical Fibre Grating Refractometers for Resin Cure Monitoring.

    OpenAIRE

    Buggy, Stephen J.; Chehura, Edmon; James, Stephen W.; Tatam, Ralph P.

    2007-01-01

    The use of fibre grating refractometers as a means of monitoring the cure of a UVcured epoxy resin is presented. The wavelength shift of the attenuation bands of a long period grating and the spectral response of a tilted fibre Bragg grating sensor were measured simultaneously during the cure of the resin and compared with measurements made using a fibre optic Fresnel based refractometer. The results showed a good correlation (6 x 10 -3 rius) and illustrate the potential of ...

  12. Simplifying the design of microstructured optical fibre pressure sensors.

    Science.gov (United States)

    Osório, Jonas H; Chesini, Giancarlo; Serrão, Valdir A; Franco, Marcos A R; Cordeiro, Cristiano M B

    2017-06-07

    In this paper, we propose a way to simplify the design of microstructured optical fibres with high sensitivity to applied pressure. The use of a capillary fibre with an embedded core allows the exploration of the pressure-induced material birefringence due to the capillary wall displacements and the photoelastic effect. An analytical description of pressure-induced material birefringence is provided, and fibre modal characteristics are explored through numerical simulations. Moreover, a capillary fibre with an embedded core is fabricated and used to probe pressure variations. Even though the embedded-core fibre has a non-optimized structure, measurements showed a pressure sensitivity of (1.04 ± 0.01) nm/bar, which compares well with more complex, specially designed fibre geometries reported in the literature. These results demonstrate that this geometry enables a novel route towards the simplification of microstructured fibre-based pressure sensors.

  13. Design and synthesis of a fluorescent molecular imprinted polymer for use in an optical fibre-based cocaine sensor

    Science.gov (United States)

    Wren, Stephen P.; Piletsky, Sergey A.; Karim, Kal; Gascoine, Paul; Lacey, Richard; Sun, Tong; Grattan, Kenneth T. V.

    2014-05-01

    Previously, we have developed chemical sensors using fibre optic-based techniques for the detection of Cocaine, utilising molecularly imprinted polymers (MIPs) containing fluorescein moieties as the signalling groups. Here, we report the computational design of a fluorophore which was incorporated into a MIP for the generation of a novel sensor that offers improved sensitivity for Cocaine with a detection range of 1-100μM. High selectivity for Cocaine over a suite of known Cocaine interferants (25μM) was also demonstrated by measuring changes in the intensity of fluorescence signals received from the sensor.

  14. The optical frequency comb fibre spectrometer.

    Science.gov (United States)

    Coluccelli, Nicola; Cassinerio, Marco; Redding, Brandon; Cao, Hui; Laporta, Paolo; Galzerano, Gianluca

    2016-10-03

    Optical frequency comb sources provide thousands of precise and accurate optical lines in a single device enabling the broadband and high-speed detection required in many applications. A main challenge is to parallelize the detection over the widest possible band while bringing the resolution to the single comb-line level. Here we propose a solution based on the combination of a frequency comb source and a fibre spectrometer, exploiting all-fibre technology. Our system allows for simultaneous measurement of 500 isolated comb lines over a span of 0.12 THz in a single acquisition; arbitrarily larger span are demonstrated (3,500 comb lines over 0.85 THz) by doing sequential acquisitions. The potential for precision measurements is proved by spectroscopy of acetylene at 1.53 μm. Being based on all-fibre technology, our system is inherently low-cost, lightweight and may lead to the development of a new class of broadband high-resolution spectrometers.

  15. The optical frequency comb fibre spectrometer

    Science.gov (United States)

    Coluccelli, Nicola; Cassinerio, Marco; Redding, Brandon; Cao, Hui; Laporta, Paolo; Galzerano, Gianluca

    2016-01-01

    Optical frequency comb sources provide thousands of precise and accurate optical lines in a single device enabling the broadband and high-speed detection required in many applications. A main challenge is to parallelize the detection over the widest possible band while bringing the resolution to the single comb-line level. Here we propose a solution based on the combination of a frequency comb source and a fibre spectrometer, exploiting all-fibre technology. Our system allows for simultaneous measurement of 500 isolated comb lines over a span of 0.12 THz in a single acquisition; arbitrarily larger span are demonstrated (3,500 comb lines over 0.85 THz) by doing sequential acquisitions. The potential for precision measurements is proved by spectroscopy of acetylene at 1.53 μm. Being based on all-fibre technology, our system is inherently low-cost, lightweight and may lead to the development of a new class of broadband high-resolution spectrometers. PMID:27694981

  16. Polymer Optical Fibre Sensors for Endoscopic Opto-Acoustic Imaging

    DEFF Research Database (Denmark)

    Broadway, Christian; Gallego, Daniel; Woyessa, Getinet

    2015-01-01

    is the physical size of the device, allowing compatibility with current technology, while governing flexibility of the distal end of the endoscope based on the needs of the sensor. Polymer optical fibre (POF) presents a novel approach for endoscopic applications and has been positively discussed and compared...... in existing publications. A great advantage can be obtained for endoscopy due to a small size and array potential to provide discrete imaging speed improvements. Optical fibre exhibits numerous advantages over conventional piezo-electric transducers, such as immunity from electromagnetic interference...... and a higher resolution at small sizes. Furthermore, micro structured polymer optical fibres offer over 12 times the sensitivity of silica fibre. We present a polymer fibre Bragg grating ultrasound detector with a core diameter of 125 microns. We discuss the ultrasonic signals received and draw conclusions...

  17. SPR-based plastic optical fibre biosensor for the detection of C-reactive protein in serum.

    Science.gov (United States)

    Aray, Ayda; Chiavaioli, Francesco; Arjmand, Mojtaba; Trono, Cosimo; Tombelli, Sara; Giannetti, Ambra; Cennamo, Nunzio; Soltanolkotabi, Mahmood; Zeni, Luigi; Baldini, Francesco

    2016-10-01

    A plastic optical fibre biosensor based on surface plasmon resonance for the detection of C-reactive protein (CRP) in serum is proposed. The biosensor was integrated into a home-made thermo-stabilized microfluidic system that allows avoiding any thermal and/or mechanical fluctuation and maintaining the best stable conditions during the measurements. A working range of 0.006-70 mg L -1 and a limit of detection of 0.009 mg L -1 were achieved. These results are among the best compared to other SPR-based biosensors for CRP detection, especially considering that they were achieved in a real and complex medium, i.e. serum. In addition, since the sensor performances satisfy those requested in physiologically-relevant clinical applications, the whole biosensing platform could well address high sensitive, easy to realize, real-time, label-free, portable and low cost diagnosis of CRP for future lab-on-a-chip applications. 3D sketch (left) of the thermo-stabilized home-made flow cell developed to house the SPR-based plastic optical fibre biosensor. Exemplary response curve (shift of the SPR wavelength versus time) of the proposed biosensor (right) for the detection of C-reactive protein in serum. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Fibre and components induced limitations in high capacity optical networks

    DEFF Research Database (Denmark)

    Peucheret, Christophe

    2003-01-01

    -drop multiplexers (OADM) and optical cross-connects (OXC), as well as those due to the interaction of group-velocity dispersion, optical fibre non-linearities and accumulation of amplifier noise in the transmission path. The dispersion of fibre optics components is shown to limit their cascadability. Dispersion...... design in order to maximise the spectral efficiency in a four add-drop node ring network. The concept of "normalised transmission sections" is introduced in order to ease the dimensioning of transparent domains in future all-optical networks. Normalised sections based on standard single mode fibre (SMF...... where IDF£2 or 3 should be preferred. The benefit of using short return-to-zero (RZ) pulses over conventional NRZ modulation in a SMF+IDF£1 link is highlighted. Short pulses disperse faster in the transmission fibre, which is in turn beneficial in terms of optical signal-to-noise ratio, resulting...

  19. Optical fibre sensing: a solution for industry

    Science.gov (United States)

    Sun, T.; Fabian, M.; Chen, Y.; Vidakovic, M.; Javdani, S.; Grattan, K. T. V.; Carlton, J.; Gerada, C.; Brun, L.

    2017-04-01

    Optical fibres have been explored widely for their sensing capability to meet increasing industrial needs, building on their success in telecommunications. This paper provides a review of research activities at City University of London in response to industrial challenges through the development of a range of fibre Bragg grating (FBG)-based sensors for transportation structural monitoring. For marine propellers, arrays of FBGs mapped onto the surface of propeller blades allow for capturing vibrational modes, with reference to simulation data. The research funded by EU Cleansky programme enables the development of self-sensing electric motor drives to support `More Electric Aircraft' concept. The partnership with Faiveley Brecknell Willis in the UK enables the integration of FBG sensors into the railway current-collecting pantographs for real-time condition monitoring when they are operating under 25kV conditions.

  20. Insertion of optic fibre for CMS

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    The MicroJET system uses high pressure to carefully put the optical fibres into their protective tubes. These fibres are vital for rapid data transfer, but are also very delicate and, if damanged, may not work at the required efficiency. Similiar methods are used to install cables for the telecommunications industry.

  1. Al-optical signal processing subsystem based on highly-nonlinear fibres and their limitations for networking applications

    Czech Academy of Sciences Publication Activity Database

    Karásek, Miroslav; Teixeira, A.; Beleffi, G. M. T.; Luis, R.

    Vol. 4534, - (2007), s. 78-85 ISSN 0302-9743. [International IFIP TC6 Conference on Optical Network Design & Modelling ONDM 2007 /11./. Athens, 29.05.2007-31.05.2007] R&D Projects: GA MŠk 1P05OC001 Institutional research plan: CEZ:AV0Z20670512 Keywords : optical communication * optical fibres * wavelenght division multiplexing Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.402, year: 2005

  2. Optical fibres bringing the LHC into focus

    CERN Multimedia

    2003-01-01

    New components are being added to CERN's optical fibre network, which will transport the torrents of data produced by the LHC. 1500 kilometres of cables will be installed in the tunnels and at ground level.

  3. Fibre optics compatibility with radiative environment inside PWR containment

    International Nuclear Information System (INIS)

    Breuze, G.; Jucker, P.; Serre, J.

    1993-01-01

    Fibre optic links operating with multiplexed sensors data are potentially attractive for nuclear power plant applications. It hence became essential to test for radiation vulnerability not only transmission support -fibres- but also fibre-end electro-optical components which could be exposed to hostile environment, perhaps in worse conditions than fibres. Present paper gives results of multimode silica-based fibre behaviour during long-term steady-state low dose-rate gamma ray exposure - one year under 0.1 to 0.2 Gy/h. Studies concerned radiation-induced loss (ΔL) measurement of eight different commercially available fibres and bit error-rate (BER) recording of four 1 100 m length data links operating with a 100 m part exposed to gamma-rays. Main result is the good behaviour of pure silica-core fibres, especially a step-index polymer-clad fibre transmitting 850 nm light but also a graded-index fluorine-clad fibre for 1 300 nm window. Mean ΔL values are respectively 3 dB/km and 4.5 dB/km at the exposure end. Complementary result is no influence of gamma-ray exposure upon data link initial 10 -9 BER. (authors). 9 figs., 7 tabs., 26 refs

  4. Natural fibres-based polymers

    Indian Academy of Sciences (India)

    Natural fibres-based polymers: Part I—Mechanical analysis of Pine needles reinforced biocomposites. Vijay Kumar Thakur A S ... Keeping in view the various advantages of natural fibres, in current series of green composites a study on natural fibre reinforced polymer composites has been made. This paper presents the ...

  5. Higher order modes of coupled optical fibres

    International Nuclear Information System (INIS)

    Alexeyev, C N; Yavorsky, M A; Boklag, N A

    2010-01-01

    The structure of hybrid higher order modes of two coupled weakly guiding identical optical fibres is studied. On the basis of perturbation theory with degeneracy for the vector wave equation expressions for modes with azimuthal angular number l ≥ 1 are obtained that allow for the spin–orbit interaction. The spectra of polarization corrections to the scalar propagation constants are calculated in a wide range of distances between the fibres. The limiting cases of widely and closely spaced fibres are studied. The obtained results can be used for studying the tunnelling of optical vortices in directional couplers and in matters concerned with information security

  6. Dimensional Measurements under High Radiation with Optical Fibre Sensors based on White Light Interferometry - Report on Irradiation Tests

    International Nuclear Information System (INIS)

    Cheymol, G.; Caron, N.; Gusarov, A.; Gaillot, S.; Destouches, C.

    2013-06-01

    Abstract-Optical fibre sensors (OFS) can bring substantial advantages over conventional sensing approaches for in-situ measurement in fission Material Testing Reactors (MTRs) and other nuclear research or industrial facilities: easy remote sensing, possibilities of multiplexing, passive operation, low sensitivity to electromagnetic interference, compact size, high resolution and accuracy even under high radiation dose and high temperature, once necessary adaptations have been achieved. In this paper firstly we remind the three undesired effects of high level of irradiation on OFS: radiation induced attenuation, radio luminescence and compaction due to fast neutrons. Then we present two types of sensor that we develop: elongation Fabry Perot sensor - jointly with SCK.CEN - and Michelson type displacement sensor; they both rely on white light interferometry to retrieve the desired measurement. We report the results of irradiation of Fabry-Perot sensors in the core of BR2 material testing reactor in Mol (Belgium), under intense neutron-gamma flux and at high temperature. Six Fabry Perot fibre optics sensors are mounted on a support insensitive to radiation. The objective is to test the survival and the drift of the sensors. The temperature is maintained steady at 200 deg. C during 22 days then the temperature is increased up to 390 deg. C. Among five sensors built according to nominal scheme, four are still alive at the end of the cycle and three show a low drift of 1 to 4 μm. These results show a clear progress compared to the previous irradiation and make it possible to consider the use of these sensors in real tests of material in MTR reactor. However, improvement in the robustness of the interfaces is still necessary. The next part is devoted to the measurement of displacements perpendicular to the direction of the lead-in fibre, of interest for small room environments where the fibre cannot make a 90 deg. turn. The optical scheme is based on the Michelson

  7. A reliable low-cost wireless and wearable gait monitoring system based on a plastic optical fibre sensor

    International Nuclear Information System (INIS)

    Bilro, L; Pinto, J L; Oliveira, J G; Nogueira, R N

    2011-01-01

    A wearable and wireless system designed to evaluate quantitatively the human gait is presented. It allows knee sagittal motion monitoring over long distances and periods with a portable and low-cost package. It is based on the measurement of transmittance changes when a side-polished plastic optical fibre is bent. Four voluntary healthy subjects, on five different days, were tested in order to assess inter-day and inter-subject reliability. Results have shown that this technique is reliable, allows a one-time calibration and is suitable in the diagnosis and rehabilitation of knee injuries or for monitoring the performance of competitive athletes. Environmental testing was accomplished in order to study the influence of different temperatures and humidity conditions

  8. EXPERIMENTAL STUDY ON LIGHT TRANSMITTING CONCRETE BY USING OPTICAL FIBRE

    OpenAIRE

    S. Suganya; S. Minu Gopika

    2017-01-01

    Light transmitting concrete is one of the fibre reinforced concrete which is mainly used for aesthetic application by incorporating the optical fibres in concrete. Optical fibres help to transmit the light through the fibres and the end-light type of fibre is used to increase the aesthetic appearance of the concrete which is like a transparent concrete. Fibres are arranged in different layers, to increase the load carrying capacity and also the pattern can be created to make the concrete deco...

  9. Sub-aquatic response of a scintillator, fibre optic and silicon photomultiplier based radiation sensor

    International Nuclear Information System (INIS)

    Jackson, Sarah-F.; Monk, Stephen D.; Lennox, Kathryn; Stanley, Steven-J.

    2013-06-01

    We describe here, the sub-aquatic response of the RadLine R detector (a small, novel, remotely operated radiation detection instrument) when irradiated with gamma doses between 6 and 400 Svhr -1 . The National Nuclear Laboratory's (NNL, UK) RadLine R consists of an inorganic scintillating crystal coupled to a fibre optic cable which transports scintillation photons to a detector at the other end. A CCD camera is normally used for photon collection, however in this paper we trial a newer technology; the silicon photomultiplier (SiPM), namely SensL's MiniSL. SiPMs have performance characteristics similar to photomultiplier tubes (PMT), whilst benefiting from the practical advantages of solid-state technology which include; low operating voltage, robustness, compactness, insensitivity to magnetic fields and over-exposure to light. The MiniSL was chosen as its peak photon wavelength is well matched to the output from the scintillation crystal, as well as its fast recovery time (within the nano-second range). We use a clinical radiotherapy linear accelerator (linac) machine which produces x-rays by accelerating elections onto a target which then emits x-rays by Bremsstrahlung. The linac is rated at 6 MeV in energy, with a peak of approximately 2 MeV. The machine is capable of generating a highly precise dose at known distances between treatment head and scintillation crystal. Analysing the data gathered we were also able consider how the RadLine R might perform in larger aquatic environments for example First Generation Magnox Storage Ponds (FGMSP). Built in the 1950's they were originally intended to hold spent nuclear fuel for reprocessing, however now parts of the spent fuel have corroded; some of which are buried under a layer of sediment. Removal is not a trivial task due to elevated radiation levels, and the complexity of the environment. RadLine R has the potential to be of significant use for this and in other similar situations. (authors)

  10. ANALYSIS OF THE ACCURACY OF FIBRE-OPTIC STRAIN GAUGES

    Directory of Open Access Journals (Sweden)

    Dita Jiroutová

    2013-12-01

    Full Text Available In recent years, the field of structure monitoring has been making increasing use of systems based on fiber-optic technologies. Fiber-optic technology offers many advantages, including higher quality measurements, greater reliability, easier installation and maintenance, insensitivity to the environment (mainly to the electromagnetic field, corrosion resistance, safety in explosive and flammable environments, the possibility of long-term monitoring and lower cost per lifetime. We have used SOFO fibre-optic strain gauges to perform measurements to check the overall relative deformation of a real reinforced concrete structure. Long-term monitoring of the structure revealed that the measurement readings obtained from these fibre-optic strain gauges differed from each other. Greater attention was therefore paid to the calibration of the fibre-optic strain gauges, and to determining their measurement accuracy. The experimental results show that it is necessary to calibrate SOFO strain gauges before they are used, and to determine their calibration constant.

  11. Liquid-phase microextraction and fibre-optics-based cuvetteless CCD-array micro-spectrophotometry for trace analysis

    International Nuclear Information System (INIS)

    Sharma, Nisha; Pillai, Aradhana K.K.V.; Pathak, Neeraj; Jain, Archana; Verma, Krishna K.

    2009-01-01

    Liquid-phase microextraction (LPME) has been investigated for trace analysis in the present work in conjunction with fibre-optic-based micro-spectrophotometry which accommodates sample volume of 1 μL placed between the two ends of optical fibres. Methods have been evolved for the determination of (i) 1-100 μM and 0.5-20 μM of thiols by single drop microextraction (SDME) and LPME in 25 μL of the organic solvent, respectively, involving their reaction with the Ellman reagent and ion pair microextraction of thiolate ion formed; (ii) 70 μg to 7 mg L -1 of chlorine/chlorine dioxide by headspace in-drop reaction with alternative reagents, viz., mixed phenylhydrazine-4-sulphonic acid and N-(1-naphthyl)ethylenediamine dihydrochloride, o-dianisidine, o-tolidine, and N,N-diethyl-p-phenylenediamine; (iii) 0.2-4 mg L -1 of ammonia by reaction with 2,4-dinitro-1-fluorobenzene to give 2,4-dinitroaniline which was diazotized and coupled with 1-naphthylamine, the resulting dye was subjected to preconcentration by solid-phase extraction and LPME; and (iv) 25-750 μg L -1 of iodide/total iodine by oxidation of iodide by 2-iodosobenzoate, microextraction of iodine in organic solvent, and re-extraction into aqueous starch-iodide reagent drop held in the organic phase. LPME using 25-30 μL of organic solvent was found to produce more sensitive results than SDME. The cuvetteless spectrophotometry as used in combination with sample handling techniques produced limits of detection of analytes which were better than obtained by previously reported spectrophotometry.

  12. Single Chromatin Fibre Assembly Using Optical Tweezers

    NARCIS (Netherlands)

    Bennink, Martin L.; Pope, L.H.; Leuba, S.H.; de Grooth, B.G.; Greve, Jan

    2001-01-01

    Here we observe the formation of a single chromatin fibre using optical tweezers. A single -DNA molecule was suspended between two micron-sized beads, one held by a micropipette and the other in an optical trap. The constrained DNA molecule was incubated with Xenopus laevis egg extract in order to

  13. Humidity insensitive step-index polymer optical fibre Bragg grating sensors

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Fasano, Andrea; Stefani, Alessio

    2015-01-01

    We have fabricated and characterised a humidity insensitive step index(SI) polymer optical fibre(POF) Bragg grating sensors. The fibre was made based on the injection molding technique, which is an efficient method for fast, flexible and cost effective preparation of the fibre preform. The fabric......We have fabricated and characterised a humidity insensitive step index(SI) polymer optical fibre(POF) Bragg grating sensors. The fibre was made based on the injection molding technique, which is an efficient method for fast, flexible and cost effective preparation of the fibre preform...

  14. Optical fibre probes in the measurement of scattered light ...

    Indian Academy of Sciences (India)

    2014-01-08

    Jan 8, 2014 ... absorption of light from the sample solution. Details of the experiments and results are presented here. Keywords. Fibre optic sensors; optical fibre probes; turbidity sensor; optical properties. PACS Nos 42.81.−I; 42.81.Pa; 78.15.+e. 1. Introduction. Apart from being the transmission medium in optical fibre ...

  15. Infrared Supercontinuum Generation in Optical Fibres

    DEFF Research Database (Denmark)

    Dupont, Sune Vestergaard Lund

    During my PhD studies I have worked with intense lasers and optical fibres. In our conceptual universe the colour of light (wavelength) does not depend on the material in which it propagates. At high intensities however, nonlinear effects change the behaviour of light and rise of new wavelength...... with laser-like intensity is obtained, which otherwise is impossible without the use of more complicated equipment. Until recently, supercontinuum covering the mid-infrared was not possible due to absorption in the silica glass optical fibres are made of. In our project infrared transparent materials...... such as ZBLAN and chalcogenide have been investigated. Using ZBLAN it has been possible to generated a supercontinuum stretching beyond 4200 nm. Supercontinuum generation requires knowledge about the physical properties of the optical fibre in which the pulse-broadening takes place. Consequently thorough...

  16. Fibre Bragg Gratings in Embedded Microstructured Optical Fibres Allow Distinguishing between Symmetric and Anti-Symmetric Lamb Waves in Carbon Fibre Reinforced Composites.

    Science.gov (United States)

    De Pauw, Ben; Goossens, Sidney; Geernaert, Thomas; Habas, Dimitrios; Thienpont, Hugo; Berghmans, Francis

    2017-08-24

    Conventional contact sensors used for Lamb wave-based ultrasonic inspection, such as piezo-electric transducers, measure omnidirectional strain and do not allow distinguishing between fundamental symmetric and anti-symmetric modes. In this paper, we show that the use of a single fibre Bragg grating created in a dedicated microstructured optical fibre allows one to directly make the distinction between these fundamental Lamb wave modes. This feature stems from the different sensitivities of the microstructured fibre to axial and transverse strain. We fabricated carbon fibre-reinforced polymer panels equipped with embedded microstructured optical fibre sensors and experimentally demonstrated the strain waves associated with the propagating Lamb waves in both the axial and transverse directions of the optical fibre.

  17. Fibre-optic laser-assisted infrared tumour diagnostics (FLAIR)

    International Nuclear Information System (INIS)

    Bindig, U; Mueller, G

    2005-01-01

    Laser based fibre-optic surgery procedures are commonly used in minimal invasive surgery. Despite the development of precise and efficient laser systems there are also innovative attempts in the field of bio-medical diagnostics. As a direct result of the tissue's optical properties most applications are focused on the visible wavelength range of the spectrum. The extension of the spectrum up to the mid-infrared (IR) region will offer a broad range of possibilities for novel strategies with a view to non-invasive diagnostics in medicine. We describe a method to detect differences between diseased and normal tissues, which involve Fourier transform IR microspectroscopy and fibre-optics methods. Regions of interest on 10 μm thin tissue sections were mapped using an IR microscope in transmission mode. After IR-mapping, the samples were analysed using standard pathological techniques. Quadratic discriminant and correlation analyses were applied to the IR maps obtained allowing differentiation between cancerous and normal tissue. The use of optical fibres, transparent in the mid-IR, allowed measurements to be made in the attenuated total reflectance (ATR)-mode at a remote location. The IR sensor is in contact with the sample that shows characteristic absorption lines. The total transmission of the fibre and the sample will decrease at these lines. This method can be used to determine the absorption of a sample in a non-destructive manner. In this paper we report on our efforts to develop an IR fibre-optic sensor for tissue identification as well as to differentiate between malignant and healthy tissue in vivo. We also describe the technical design of the laboratory set-up and the results of developments made. Silver halide fibres and a special sensor tip were used for the ATR measurements on tissue specimens. The results indicate that fibre-optic IR spectrometry will be a useful tool for bio-diagnostics

  18. Fibre-optic laser-assisted infrared tumour diagnostics (FLAIR)

    Science.gov (United States)

    Bindig, U.; Müller, G.

    2005-08-01

    Laser based fibre-optic surgery procedures are commonly used in minimal invasive surgery. Despite the development of precise and efficient laser systems there are also innovative attempts in the field of bio-medical diagnostics. As a direct result of the tissue's optical properties most applications are focused on the visible wavelength range of the spectrum. The extension of the spectrum up to the mid-infrared (IR) region will offer a broad range of possibilities for novel strategies with a view to non-invasive diagnostics in medicine. We describe a method to detect differences between diseased and normal tissues, which involve Fourier transform IR microspectroscopy and fibre-optics methods. Regions of interest on 10 µm thin tissue sections were mapped using an IR microscope in transmission mode. After IR-mapping, the samples were analysed using standard pathological techniques. Quadratic discriminant and correlation analyses were applied to the IR maps obtained allowing differentiation between cancerous and normal tissue. The use of optical fibres, transparent in the mid-IR, allowed measurements to be made in the attenuated total reflectance (ATR)-mode at a remote location. The IR sensor is in contact with the sample that shows characteristic absorption lines. The total transmission of the fibre and the sample will decrease at these lines. This method can be used to determine the absorption of a sample in a non-destructive manner. In this paper we report on our efforts to develop an IR fibre-optic sensor for tissue identification as well as to differentiate between malignant and healthy tissue in vivo. We also describe the technical design of the laboratory set-up and the results of developments made. Silver halide fibres and a special sensor tip were used for the ATR measurements on tissue specimens. The results indicate that fibre-optic IR spectrometry will be a useful tool for bio-diagnostics.

  19. Signal Generation for Radio Over Fibre Systems Based on Optical Combination

    Directory of Open Access Journals (Sweden)

    Muñoz-Ortiz Rafael Oswaldo

    2015-09-01

    Full Text Available This paper presents a comparative study of the signal generation techniques for the transport of information in Radio over Fiber (RoF systems by using optical combination techniques. In these systems, the radio frequency carriers are conveyed as optical subcarriers over a link in a point-to-point or point-to-multipoint connectivity paradigm. This study is focused on three different generation techniques: double arm, parallel and serial generation. An analytical model to describe the elements, the configuration and the processes involved in the RoF signal generation is defined for each one of them. Subsequently, a modeling of the obtained electrical field functions allows assessing the quality of the generated signals based on the modulation depth. Results show that while there is a trade-off between the modulation depths of both signals for the double arm and serial configuration, the parallel technique relaxes the establishment of different modulation depths. An optimum configuration that guarantees a good quality for the generated signals is found for each generation technique.

  20. Advanced Fibre Based Energy Storage

    Science.gov (United States)

    Reid, Daniel Oliver

    New energy storage devices are required to enable future technologies. With the rise of wearable consumer and medical devices, a suitable flexible and wearable means of storing electrical energy is required. Fibre-based devices present a possible method of achieving this aim. Fibres are inherently more flexible than their bulk counterparts, and as such can be employed to form the electrodes of flexible batteries and capacitors. They also present a facile possibility for incorporation into many fabrics and clothes, further boosting their potential for use in wearable devices. Electrically conducting fibres were produced from a dispersion of carbon nanomaterials in a room temperature ionic liquid. Coagulation of this dispersion was achieved through manual injection into aqueous solutions of xanthan gum. The limitations of this method are highlighted by very low ultimate tensile strengths of these fibres, in the order of 3 MPa, with high variation within all of the fibres. Fibres were also produced via scrolling of bi-component films containing poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and poly(vinyl alcohol) (PVA). Chemical treatments were employed to impart water compatibility to these fibres, and their electrochemical, physical and electrical properties were analysed. Fibres were wet spun from two PEDOT:PSS sources, in several fibre diameters. The effect of chemical treatments on the fibres were investigated and compared. Short 5 min treatment times with dimethyl sulfoxide (DMSO) on 20 mum fibres produced from Clevios PH1000 were found to produce the best overall treatment. Up to a six-fold increase in electrical conductivity resulted, reaching 800 S cm-1, with up to 40 % increase in specific capacitance and no loss of mechanical strength (55 F g-1 and 150 MPa recorded). A wet spinning system to produce PEDOT:PSS fibres containing functionalised graphenes and carbon nanotubes, as well as birnessite nanotubes was subsequently developed

  1. Optical rogue waves and soliton turbulence in nonlinear fibre optics

    DEFF Research Database (Denmark)

    Genty, G.; Dudley, J. M.; de Sterke, C. M.

    2009-01-01

    We examine optical rogue wave generation in nonlinear fibre propagation in terms of soliton turbulence. We show that higher-order dispersion is sufficient to generate localized rogue soliton structures, and Raman scattering effects are not required.......We examine optical rogue wave generation in nonlinear fibre propagation in terms of soliton turbulence. We show that higher-order dispersion is sufficient to generate localized rogue soliton structures, and Raman scattering effects are not required....

  2. Measuring method for optical fibre sensors

    NARCIS (Netherlands)

    Lammerink, Theodorus S.J.; Fluitman, J.H.J.

    1984-01-01

    A new measuring method for the signal amplitude in intensity modulating fibre optic sensors is described. A reference signal is generated in the time domain. The method is insensitive for the sensitivity fluctuations of the light transmitter and the light receiver. The method is experimentally

  3. Control systems in optical fibre industry

    Czech Academy of Sciences Publication Activity Database

    Kostka, František

    1998-01-01

    Roč. 1, č. 4 (1998), s. 195-200 ISSN 1405-5546 Grant - others:AV ČR(CZ) KSK1067601 Projekt 10/96/K:4107 Keywords : control systems * real time systems * microcomputers * optical fibres Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  4. Fabrication of Polymer Optical Fibre (POF) Gratings.

    Science.gov (United States)

    Luo, Yanhua; Yan, Binbin; Zhang, Qijin; Peng, Gang-Ding; Wen, Jianxiang; Zhang, Jianzhong

    2017-03-04

    Gratings inscribed in polymer optical fibre (POF) have attracted remarkable interest for many potential applications due to their distinctive properties. This paper overviews the current state of fabrication of POF gratings since their first demonstration in 1999. In particular we summarize and discuss POF materials, POF photosensitivity, techniques and issues of fabricating POF gratings, as well as various types of POF gratings.

  5. A fibre optic chemical sensor for the detection of cocaine

    Science.gov (United States)

    Nguyen, T. Hien; Sun, Tong; Grattan, Kenneth T. V.; Hardwick, S. A.

    2010-09-01

    A fibre-optic chemical sensor for the detection of cocaine has been developed, based on a molecularly imprinted polymer (MIP) containing a fluorescein moiety as the signalling group. The fluorescent MIP was formed and covalently attached to the distal end of an optical fibre. The sensor exhibited an increase in fluorescence intensity in response to cocaine in the concentration range of 0 - 500 μM in aqueous acetonitrile mixtures with good reproducibility over 24 h. Selectivity for cocaine over others drugs has also been demonstrated.

  6. Reliability of fibre Bragg gratings in polymer optical fibre

    OpenAIRE

    Dobb, H.; Carroll, K.; Kalli, K.; Komodromos, M.; Themistos, C.; Peng, G.D.; Argyros, A.; Large, M.C.J.; van Eijkelenborg, M.A.; Arresy, M.; Kukureka, S.

    2006-01-01

    In this paper we report on investigations of some of the factors that have a bearing on the reliability and repeatability of polymer fibre Bragg gratings. The main issues discussed are the fibre preform composition, the fibre drawing conditions and the thermal history of the fibre grating.

  7. Design of optical fibres with advanced modal control properties

    DEFF Research Database (Denmark)

    Muliar, Olena

    an experimental characterisation of the modelled 19-cell HC PBGF was conducted. A modal content evaluation within a broad wavelength range was performed by a modified S 2 technique with a spectrogram approach. Results of the experimental and numerical fibre analysis were compared. It was revealed, that in 10m...... has increased interest to HOMs as independent spatial data channels for mode division multiplexing (MDM). The primary aim of this thesis is the investigation, modelling and experimental evaluation of HOMs in an optical fibre of advanced design, suitable for a MDM implementation. In order to achieve...... this goal, an interferometric-based fibre characterisation technique, known as a cross-correlated (C 2 ) imaging, was explored. An alternative modal reconstruction approach by 2D Fourier transform was presented, that allowed to extract intensity and phase distributions of the fibre mode from a single...

  8. Miniaturised Optical Fibre Sensor for Dew Detection Inside Organ Pipes

    Directory of Open Access Journals (Sweden)

    Francesco Baldini

    2008-01-01

    Full Text Available A new optical sensor for the continuous monitoring of the dew formation inside organ pipes was designed. This aspect is particularly critical for the conservation of organs in unheated churches since the dew formation or the condensation on the pipe surfaces can contribute to many kinds of physical and chemical disruptive mechanisms. The working principle is based on the change in the reflectivity which is observed on the surface of the fibre tip, when a water layer is formed on its distal end. Intensity changes of the order of 35% were measured, following the formation of the water layer on the distal end of a 400/430 μm optical fibre. Long-term tests carried out placing the fibre tip inside the base of an in-house-made metallic foot of an organ pipe located in an external environment revealed the consistency of the proposed system.

  9. Intensity-based fibre-optic sensing system using contrast modulation of subcarrier interference pattern

    Science.gov (United States)

    Adamovsky, G.; Sherer, T. N.; Maitland, D. J.

    1989-01-01

    A novel technique to compensate for unwanted intensity losses in a fiber-optic sensing system is described. The technique involves a continuous sinusoidal modulation of the light source intensity at radio frequencies and an intensity sensor placed in an unbalanced interferometer. The system shows high sensitivity and stability.

  10. Fibre optic sensors in pressurized water reactor alternators

    International Nuclear Information System (INIS)

    Favennec, J.M.; Piguet, M.

    1994-01-01

    Measurement in the electrical engine environment (alternator, transformer...) is identified as one of the two main applications of fibre optic sensors within EDF; the other application niche is the monitoring of civil works (dams, containment building of nuclear reactors...). At the EDF Research and Development Division, temperature and vibration fibre optic sensors were evaluated by the Metrology Service, since their use is under consideration for alternator monitoring. For alternator stator thermal monitoring, the BERTIN company developed a fibre optic sensor network. The optic coding technique is based on broadband source spectral modulation; the sensors are interrogated sequentially by electronic commutation. For alternator stator vibration monitoring, a fibre optic accelerometer was developed in the frame of a manufacturers and universities consortium supported by the French Research and Technology Ministry. The accelerometer is of cantilever beam type and its networking is possible by chromatic multiplexing. The Metrology Service evaluated these temperature and vibration sensors in order to verify their metrological characteristics (bias error, hysteresis, repeatability, resolution, noise, amplitude linearity, response time, frequency response, etc.) and to test their behaviour in harsh alternator environmental conditions (pressure, vibrations and temperature). Ageing and accidental condition resistance tests were also carried out. Temperature sensor test results were very satisfactory. An eight-sensor BERTIN prototype was installed on the Tricastin 1 alternator during the september 1993 nuclear station periodic stop. On the contrary, the accelerometers presented deficient metrological characteristics (shorter span than foreseen, low repeatability...). They need some improvements and could not be installed on alternators. (authors). 5 refs., 8 figs

  11. Optical fibre probes in the measurement of scattered light ...

    Indian Academy of Sciences (India)

    2014-01-08

    based mea- surements and sensors. An optrode usually comprises a bundle of multimode fibres, out of which one or more fibres are used for irradiating the sample, and the remaining fibres are used to collect the.

  12. Gallium arsenide deep-level optical emitter for fibre optics.

    Science.gov (United States)

    Pan, Janet L; McManis, Joseph E; Osadchy, Thomas; Grober, Louise; Woodall, Jerry M; Kindlmann, Peter J

    2003-06-01

    Fibre-optic components fabricated on the same substrate as integrated circuits are important for future high-speed communications. One industry response has been the costly push to develop indium phosphide (InP) electronics. However, for fabrication simplicity, reliability and cost, gallium arsenide (GaAs) remains the established technology for integrated optoelectronics. Unfortunately, the GaAs bandgap wavelength (0.85 microm) is far too short for fibre optics at 1.3-1.5 microm. This has led to work on materials that have a large lattice mismatch on GaAs. Here we demonstrate the first light-emitting diode (LED) that emits at 1.5 microm fibre-optic wavelengths in GaAs using optical transitions from arsenic antisite (As(Ga)) deep levels. This is an enabling technology for fibre-optic components that are lattice-matched to GaAs integrated circuits. We present experimental results showing significant internal optical power (24 mW) and speed (in terahertz) from GaAs optical emitters using deep-level transitions. Finally, we present theory showing the ultimate limit to the efficiency-bandwidth product of semiconductor deep-level optical emitters.

  13. Advanced fibre based energy storage.

    OpenAIRE

    Reid, Daniel

    2017-01-01

    New energy storage devices are required to enable future technologies. With the rise of wearable consumer and medical devices, a suitable flexible and wearable means of storing electrical energy is required. Fibre-based devices present a possible method of achieving this aim. Fibres are inherently more flexible than their bulk counterparts, and as such can be employed to form the electrodes of flexible batteries and capacitors. They also present a facile possibility for incorporation into man...

  14. Fabrication of Polymer Optical Fibre (POF Gratings

    Directory of Open Access Journals (Sweden)

    Yanhua Luo

    2017-03-01

    Full Text Available Gratings inscribed in polymer optical fibre (POF have attracted remarkable interest for many potential applications due to their distinctive properties. This paper overviews the current state of fabrication of POF gratings since their first demonstration in 1999. In particular we summarize and discuss POF materials, POF photosensitivity, techniques and issues of fabricating POF gratings, as well as various types of POF gratings.

  15. Zeonex Microstructured Polymer Optical Fibre Bragg Grating Sensor

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Fasano, Andrea; Markos, Christos

    2016-01-01

    We fabricated an endlessly single mode and humidity insensitive Zeonex microstructured polymer optical fibre (mPOF) for fibre Bragg grating (FBG) temperature and strain sensors. We inscribed and characterise FBGs in Zeonex mPOF for the first time.......We fabricated an endlessly single mode and humidity insensitive Zeonex microstructured polymer optical fibre (mPOF) for fibre Bragg grating (FBG) temperature and strain sensors. We inscribed and characterise FBGs in Zeonex mPOF for the first time....

  16. The techniques of optical fibre measurements: An overall description

    International Nuclear Information System (INIS)

    Liu Zhenyuan.

    1990-11-01

    In this paper some advanced methods of measurement in the field of optical fibre measurement techniques are briefly described. They are used in measuring optical characteristics, geometrical characteristics and optical transmission characteristics of optical fibres. The standard methods recommended by CCITT are discussed as the main parts. (author). 13 refs, 8 figs, 2 tabs

  17. A Continuously Tunable Erbium-Doped Fibre Laser Using Tunable Fibre Bragg Gratings and Optical Circulator

    International Nuclear Information System (INIS)

    Peng, Liu; Feng-Ping, Yan; Jian, Li; Lin, Wang; Ti-Gang, Ning; Tao-Rong, Gong; Shui-Sheng, Jian

    2008-01-01

    A continuously tunable erbium-doped fibre laser (TEDFL) based on tunable fibre Bragger grating (TFBG) and a three-port optical circulator (OC) is proposed and demonstrated. The OC acts as a 100%-reflective mirror. A strain-induced uniform fibre Bragger grating (FBG) which functions as a partial-reflecting mirror is implemented in the linear cavity. By applying axial strain onto the TFBG, a continuously tunable lasing output can be realized. The wavelength tuning range covers approximately 7.00nm in C band (from 1543.6161 to 1550.3307nm). The side mode suppression ratio (SMSR) is better than 50 dB, and the 3 dB bandwidth of the laser is less than 0.01 nm. Moreover, an array waveguide grating (AWG) is inserted into the cavity for wavelength preselecting, and a 50 km transmission experiment was performed using our TEDFL at a 10Gb/s modulation rate

  18. High-speed signal processing using highly nonlinear optical fibres

    DEFF Research Database (Denmark)

    Peucheret, Christophe; Oxenløwe, Leif Katsuo; Mulvad, Hans Christian Hansen

    2009-01-01

    We review recent progress in all-optical signal processing techniques making use of conventional silica-based highly nonlinear fibres. In particular, we focus on recent demonstrations of ultra-fast processing at 640 Gbit/s and above, as well as on signal processing of novel modulation formats...... relying on the phase of the optical field. Topics covered include all-optical switching of 640 Gbit/s and 1.28 Tbit/s serial data, wavelength conversion at 640 Gbit/s, optical amplitude regeneration of differential phase shift keying (DPSK) signals, as well as midspan spectral inversion for differential 8...

  19. A suite of optical fibre sensors for structural condition monitoring

    Science.gov (United States)

    Sun, T.; Grattan, K. T. V.; Carlton, J.

    2015-05-01

    This paper is to review the research activities at City University London in the development of a range of fibre Bragg grating (FBG)-based sensors, including strain, temperature, relative humidity, vibration and acoustic sensors, with an aim to meet the increasing demands from industry for structural condition monitoring. As a result, arrays of optical fibre sensors have been instrumented into various types of structures, including concrete, limestone, marine propellers, pantograph and electrical motors, allowing for both static and dynamic monitoring and thus enhanced structural reliability and integrity.

  20. High Speed Fibre Optic Backbone LAN

    Science.gov (United States)

    Tanimoto, Masaaki; Hara, Shingo; Kajita, Yuji; Kashu, Fumitoshi; Ikeuchi, Masaru; Hagihara, Satoshi; Tsuzuki, Shinji

    1987-09-01

    Our firm has developed the SUMINET-4100 series, a fibre optic local area network (LAN), to serve the communications system trunk line needs for facilities, such as steel refineries, automobile plants and university campuses, that require large transmission capacity, and for the backbone networks used in intelligent building systems. The SUMINET-4100 series is already in service in various fields of application. Of the networks available in this series, the SUMINET-4150 has a trunk line speed of 128 Mbps and the multiplexer used for time division multiplexing (TDM) was enabled by designing an ECL-TTL gate array (3000 gates) based custom LSI. The synchronous, full-duplex V.24 and V.3.5 interfaces (SUMINET-2100) are provided for use with general purpose lines. And the IBM token ring network, the SUMINET-3200, designed for heterogeneous PCs and the Ethernet can all be connected to sub loops. Further, the IBM 3270 TCA and 5080 CADAM can be connected in the local mode. Interfaces are also provided for the NTT high-speed digital service, the digital PBX systems, and the Video CODEC system. The built-in loop monitor (LM) and network supervisory processor (NSP) provide management of loop utilization and send loop status signals to the host CPU's network configuration and control facility (NCCF). These built-in functions allow both the computer system and LAN to be managed from a single source at the host. This paper outlines features of the SUMINET-4150 and provides an example of its installation.

  1. Waveguidance by the photonic bandgap effect in optical fibres

    DEFF Research Database (Denmark)

    Broeng, Jes; Søndergaard, Thomas; Barkou, Stig Eigil

    1999-01-01

    technology for such photonic bandgap (PBG) waveguides is in optical fibre configurations. These new fibres can be classified in a fundamentally different way to all optical waveguides and possess radically different guiding properties due to PBG guidance, as opposed to guidance by total internal refelction....... In this paper we summarize and review our theoretical work demonstrating the underlying physical principles of PBG guiding optical fibres and discuss some of their unique waveguiding properties....

  2. A novel method of rapidly modeling optical properties of actual photonic crystal fibres

    International Nuclear Information System (INIS)

    Li-Wen, Wang; Shu-Qin, Lou; Wei-Guo, Chen; Hong-Lei, Li

    2010-01-01

    The flexible structure of photonic crystal fibre not only offers novel optical properties but also brings some difficulties in keeping the fibre structure in the fabrication process which inevitably cause the optical properties of the resulting fibre to deviate from the designed properties. Therefore, a method of evaluating the optical properties of the actual fibre is necessary for the purpose of application. Up to now, the methods employed to measure the properties of the actual photonic crystal fibre often require long fibre samples or complex expensive equipments. To our knowledge, there are few studies of modeling an actual photonic crystal fibre and evaluating its properties rapidly. In this paper, a novel method, based on the combination model of digital image processing and the finite element method, is proposed to rapidly model the optical properties of the actual photonic crystal fibre. Two kinds of photonic crystal fibres made by Crystal Fiber A/S are modeled. It is confirmed from numerical results that the proposed method is simple, rapid and accurate for evaluating the optical properties of the actual photonic crystal fibre without requiring complex equipment. (rapid communication)

  3. The analysis of an optical fibre communication system using laser ...

    African Journals Online (AJOL)

    Fibre dispersion has been the main limitation to high-speed data transmissions employing optical fibres. Various techniques and methods for combating this limitation have therefore been proposed. Such techniques include electrical and optical dispersion compensation, optical and electrical pulse shaping, and ...

  4. Optical fibre Bragg grating recorded in TOPAS cyclic olefin copolymer

    DEFF Research Database (Denmark)

    Johnson, I.P.; Yuan, Scott Wu; Stefani, Alessio

    2011-01-01

    A report is presented on the inscription of a fibre Bragg grating into a microstructured polymer optical fibre fabricated from TOPAS cyclic olefin copolymer. This material offers two important advantages over poly (methyl methacrylate), which up to now has formed the basis for polymer fibre Bragg...

  5. Fibre Bragg Grating and Long Period Grating Sensors in Polymer Optical Fibres

    OpenAIRE

    Bundalo, Ivan-Lazar; Bang, Ole; Nielsen, Kristian

    2017-01-01

    The work presented in this thesis focuses on improving the fabrication of Fibre Bragg Gratings (FBGs) and Long Period Gratings (LPGs) in microstructure polymer optical fibres (mPOF). It also focuses on exploring new options for biomedical and acoustic sensing with the purpose of expanding the range of applications and pushing the limits. The first part of the work focuses on the fabrication of FBGs in polymer optical fibres. FBGs are a periodic perturbation of the refractive index of the opti...

  6. Try This: Jelly Optical Fibre

    Science.gov (United States)

    Kellett, Sarah

    2015-01-01

    As part of the celebration of the international year of light and light-based technologies, this article presents an activity involving boiling water, sharp knives, gelatin powder, and a laser pointer. Students are instructed never look directly at a laser pointer because it can damage the eyes, and to make sure a responsible adult is present at…

  7. Simple Room Temperature Method for Polymer Optical Fibre Cleaving

    DEFF Research Database (Denmark)

    Saez-Rodriguez, David; Nielsen, Kristian; Bang, Ole

    2015-01-01

    In this paper, we report on a new method to cleave polymer optical fibre. The most common way to cut a polymer optical fibre is chopping it with a razor blade; however, in this approach both the fibre and the blade must be preheated in order to turn the material ductile, and thus, prevent crazing....... In this paper, we make use of the temperature-time equivalence in polymers to replace the use of heating by an increase of the cleaving time and use a sawing motion to reduce fibre end face damage. In this way, the polymer fibre can be cleaved at room temperature in seconds with the resulting end face being...

  8. Fibre optic system for biochemical and microbiological sensing

    International Nuclear Information System (INIS)

    Penwill, L A; Slater, J H; Hayes, N W; Tremlett, C J

    2007-01-01

    This poster will discuss state-of-the-art fibre optic sensors based on evanescent wave technology emphasising chemophotonic sensors for biochemical reactions and microbe detection. Devices based on antibody specificity and unique DNA sequences will be described. The development of simple sensor devices with disposable single use sensor probes will be illustrated with a view to providing cost effective field based or point of care analysis of major themes such as hospital acquired infections or bioterrorism events. This presentation will discuss the nature and detection thresholds required, the optical detection techniques investigated, results of sensor trials and the potential for wider commercial application

  9. Annealing and etching effects on strain and stress sensitivity of polymer optical fibre Bragg grating sensors

    DEFF Research Database (Denmark)

    Pospori, A.; Marques, C. A.F.; Sáez-Rodríguez, D.

    2017-01-01

    Thermal annealing and chemical etching effects on the strain and stress sensitivity of polymer optical fibre based sensors are investigated. Bragg grating sensors have been photo-inscribed in PMMA optical fibre and their strain and stress sensitivity has been characterised before and after any...... annealing or etching process. The annealing and etching processes have been tried in different sequence in order to investigate their impact on the sensor's performance. Results show with high confidence that fibre annealing can improve both strain and stress sensitivities. The fibre etching can also...

  10. Distributed gas sensing with optical fibre photothermal interferometry.

    Science.gov (United States)

    Lin, Yuechuan; Liu, Fei; He, Xiangge; Jin, Wei; Zhang, Min; Yang, Fan; Ho, Hoi Lut; Tan, Yanzhen; Gu, Lijuan

    2017-12-11

    We report the first distributed optical fibre trace-gas detection system based on photothermal interferometry (PTI) in a hollow-core photonic bandgap fibre (HC-PBF). Absorption of a modulated pump propagating in the gas-filled HC-PBF generates distributed phase modulation along the fibre, which is detected by a dual-pulse heterodyne phase-sensitive optical time-domain reflectometry (OTDR) system. Quasi-distributed sensing experiment with two 28-meter-long HC-PBF sensing sections connected by single-mode transmission fibres demonstrated a limit of detection (LOD) of ∼10 ppb acetylene with a pump power level of 55 mW and an effective noise bandwidth (ENBW) of 0.01 Hz, corresponding to a normalized detection limit of 5.5ppb⋅W/Hz. Distributed sensing experiment over a 200-meter-long sensing cable made of serially connected HC-PBFs demonstrated a LOD of ∼ 5 ppm with 62.5 mW peak pump power and 11.8 Hz ENBW, or a normalized detection limit of 312ppb⋅W/Hz. The spatial resolution of the current distributed detection system is limited to ∼ 30 m, but it is possible to reduce down to 1 meter or smaller by optimizing the phase detection system.

  11. Evaluation of Fibre Lifetime in Optical Ground Wire Transmission Lines

    Science.gov (United States)

    Grunvalds, R.; Ciekurs, A.; Porins, J.; Supe, A.

    2017-06-01

    In the research, measurements of polarisation mode dispersion of two OPGWs (optical ground wire transmission lines), in total four fibres, have been carried out, and the expected lifetime of the infrastructure has been assessed on the basis of these measurements. The cables under consideration were installed in 1995 and 2011, respectively. Measurements have shown that polarisation mode dispersion values for cable installed in 1995 are four times higher than that for cable installed in 2011, which could mainly be explained by technological differences in fibre production and lower fibre polarisation mode dispersion requirements in 1995 due to lack of high-speed (over 10 Gbit/s) optical transmission systems. The calculation methodology of non-refusal work and refusal probabilities, using the measured polarisation mode dispersion parameters, is proposed in the paper. Based on reliability calculations, the expected lifetime is then predicted, showing that all measured fibres most likely will be operational within minimum theoretical service life of 25 years accepted by the industry.

  12. On the use of optical fibre sensors in nuclear environment; Utilisation des capteurs a fibre optique en environnement nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Brichard, B. [SCK-CEN - Studiecentrum voor Kernenergie - Centre d' Etude de l' Energie Nucleaire, Belgian Nuclear Research Center, Mol (Belgium)

    2010-03-15

    This paper aims to provide a new insight on the use of optical fibre sensors for nuclear applications. We report on the possibilities for radiation resistance improvement using hydrogenation techniques as well as on the behaviour of various sensors exposed to radiation such as the distributed temperature sensor based on Raman effect, high-temperature Bragg gratings and a gamma ray monitor using Cerenkov luminescence. A short discussion regarding the radiation resistance of photonic crystal fibres is also briefly presented. (author)

  13. Optical fibre temperature sensor technology and potential application in absorbed dose calorimetry

    International Nuclear Information System (INIS)

    Allen, P.D.; Hargrave, N.J.

    1992-09-01

    Optical fibre based sensors are proposed as a potential alternative to the thermistors traditionally used as temperature sensors in absorbed dose calorimetry. The development of optical fibre temperature sensor technology over the last ten years is reviewed. The potential resolution of various optical techniques is assessed with particular reference to the requirements of absorbed dose calorimetry. Attention is drawn to other issues which would require investigation before the development of practical optical fibre sensors for this purpose could occur. 192 refs., 5 tabs., 4 figs

  14. Characteristics of SBS dynamics in single-mode optical fibres

    Energy Technology Data Exchange (ETDEWEB)

    Gordeev, A A; Efimkov, V F; Zubarev, I G; Mikhailov, S I; Sobolev, V B [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2016-03-31

    The characteristics of the gain of Stokes pulses in single-mode optical fibres by stimulated Brillouin scattering (SBS) of monochromatic and nonmonochromatic pump signals have been investigated by numerical simulation using a spectral approach. Conditions under which 'slow light' (caused by a group delay) can be implemented are found (it is reasonable to apply this term to a process in which a pulse is delayed with conservation of its shape). The plane-wave interaction model is shown to describe adequately the dynamics of this process in single-mode fibres. A number of gain modes are investigated for Stokes pulses with different time structures upon monochromatic and nonmonochromatic excitation. A new data transfer technique is proposed, which is based on the conversion of stepwise phase modulation of the input Stokes signal into amplitude modulation of the output signal. (nonlinear optical phenomena)

  15. Corrosion induced strain monitoring through fibre optic sensors

    International Nuclear Information System (INIS)

    Grattan, S K T; Basheer, P A M; Taylor, S E; Zhao, W; Sun, T; Grattan, K T V

    2007-01-01

    The use of strain sensors is commonplace within civil engineering. Fibre optic strain sensors offer a number of advantages over the current electrical resistance type gauges. In this paper the use of fibre optic strain sensors and electrical resistance gauges to monitor the production of corrosion by-products has been investigated and reported

  16. Effect of temperature on the active properties of erbium-doped optical fibres

    Energy Technology Data Exchange (ETDEWEB)

    Kotov, L V [Moscow Institute of Physics and Technology (State University), Dolgoprudnyi, Moscow Region (Russian Federation); Ignat' ev, A D [FORC - Photonics group, Moscow (Russian Federation); Bubnov, M M; Likhachev, M E [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation)

    2016-03-31

    We have studied the effect of heating on the performance of erbium-doped fibre based devices and determined temperaturedependent absorption and emission cross sections of the erbium ion in silica glass. The results demonstrate that heating of fibres in claddingpumped high-power (∼100 W) erbium-doped fibre lasers causes no significant decrease in their efficiency. In contrast, superluminescent sources operating in the long-wavelength region (1565 – 1610 nm) are extremely sensitive to temperature changes. (fiber optics)

  17. Potential applications of micro-optic technology for next-generation fibre optic connectivity solutions exploitable in access networks

    Science.gov (United States)

    Watté, Jan; Petersen, Rainer

    2010-05-01

    The potential of fibre-optic connectivity based on micro-optical components for deployment at particular nodes of telecom access networks will be addressed. Low-cost micro-optic components which can be manufactured by high volume replication techniques can provide new functionalities or lead to optical performance improvements of permanent or demateable fibre connections. Some of the most interesting applications involving refractive micro lenses and new fibre alignment structures will be highlighted. Numerical simulations will be presented showing that expanded beam connectors are more robust to pollution than physical contact ferrule-based connectors. The advantages and drawbacks of expanded beam fibre coupling versus physical contact connectivity based on existing and micro-optical structures are discussed.

  18. Fibre optic gyroscopes for space use

    Science.gov (United States)

    Faussot, Nicolas; Cottreau, Yann; Hardy, Guillaume; Simonpietri, Pascal; Gaiffe, Thierry

    2017-11-01

    Among the technologies available for gyroscopes usable in space, the Fibre Optic Gyroscope (FOG) technology appears to be the most suitable: no moving parts, very good lifetime, low power consumption, very low random walk, arbitrarily low angular resolution and very good behaviour in radiations and vacuum. Benefiting from more than ten years of experience with this technology, Ixsea (formerly the Navigation Division of Photonetics) is developing space FOG under both CNES and ESA contracts since many years. In the 1996-1998 period, two space FOG demonstrators in the 0,01°/h class were manufactured, including an optical head (optic and optoelectronic part) designed for space use and a standard ground electronics. Beyond the demonstration of the specified FOG performances, the behaviour of the optical head has been validated for use in typical space environment: vibrations, shocks, radiations (up to 50 krad) and thermal vacuum. Since the beginning of 1999, Ixsea is developing a space electronics in order to manufacture two complete space FOG. The first one entered in qualification in October. The second one will be delivered beginning of next year, it will be used in a CNES attitude measurement experiment (MAGI) onboard the FrenchBrazilian Microsatellite (FBM) partly dedicated to technology evaluation.

  19. Multimode laser emission from dye-doped hollow polymer optical fibre

    Indian Academy of Sciences (India)

    2014-02-09

    Feb 9, 2014 ... Well-resolved multimode laser emission was observed for the first time from a freestanding microring cavity based on Rhodamine B dye-doped hollow polymer optical fibre by transverse pumping. Fibres with different diameters such as 180, 460, 640 and 800 m were fabricated from a dye-doped hollow ...

  20. Using a fibre-optic cable as Distributed Acoustic Sensor for Vertical Seismic Profiling – Overview of various field tests

    OpenAIRE

    J. Götz; S. Lueth; J. Henninges; Thomas Reinsch

    2015-01-01

    Fibre-optic Distributed Acoustic Sensing (DAS) or Distributed Vibration Sensing (DVS) is a technology, where an optical fibre cable is used as a sensor for acoustic signals. An ambient seismic wavefield, which is coupled by friction or pressure to the optical fibre, induces dynamic strain changes along the cable. The DAS/DVS technology offers the possibility to record an optoelectronic signal which is linearly related to the time dependent local strain. The DAS/DVS technology is base...

  1. Performance emulation and parameter estimation for nonlinear fibre-optic links

    DEFF Research Database (Denmark)

    Piels, Molly; Porto da Silva, Edson; Zibar, Darko

    2016-01-01

    Fibre-optic communication systems, especially when operating in the nonlinear regime, generally do not perform exactly as theory would predict. A number of methods for data-based evaluation of nonlinear fibre-optic link parameters, both for accurate performance emulation and optimization, are rev......Fibre-optic communication systems, especially when operating in the nonlinear regime, generally do not perform exactly as theory would predict. A number of methods for data-based evaluation of nonlinear fibre-optic link parameters, both for accurate performance emulation and optimization......, are reviewed. In particular, single-step nonlinear impairment based on the Gaussian mixture model, adaptive digital backpropagation, and extension to higher-dimensional spaces using Monte Carlo Markov chains are discussed....

  2. Influence of dose history on thermoluminescence response of Ge-doped silica optical fibre dosimeters

    International Nuclear Information System (INIS)

    Moradi, F.; Mahdiraji, G.A.; Dermosesian, E.; Khandaker, M.U.; Ung, N.M.; Mahamd Adikan, F.R.; Amin, Y.M.

    2017-01-01

    Nowadays, silica based optical fibres show enough potential to be used as TL dosimeters in different applications. Reuse of optical fibre as a practical dosimeter demands to complete removal of accumulated doses via previous irradiations. This work investigates the existence and/or effect of remnant doses in fibre dosimeter from the previous irradiations, and proposes a method to control this artifact. A single mode Ge-doped optical fibre is used as TL radiation sensor, while a well calibrated Gammacell with 60 Co source is used for irradiations. The effect of irradiation history on the TL response of optical fibres is surveyed extensively for doses ranged from 1 to 1000 Gy. The results show that the absorbed dose history in a fibre affects its response in the next irradiation cycles. It is shown that a dose history of around 100 Gy can increase the response of optical fibre by a factor of 1.72. The effect of annealing at higher temperatures on stabilizing the fibre response is also examined and results revealed that another alteration in the structure of trapping states occurs in glass medium which can change the sensitivity of fibres. Preservation of the sensitivity during successive irradiation cycles can be achieved by a proper annealing procedure accompanied by a pre-dose treatment. - Highlights: • Influence of dose history on TL characteristics of fibre dosimeter is explored. • The phenomenon behind the TL variation caused by dose history is discussed. • Effect of annealing temperature on performance of fibre dosimeter is studied. • Pre-treatment methods for mitigating variation in reproducibility are proposed.

  3. Characteristics of SBS dynamics in single-mode optical fibres

    Science.gov (United States)

    Gordeev, A. A.; Efimkov, V. F.; Zubarev, I. G.; Mikhailov, S. I.; Sobolev, V. B.

    2016-03-01

    The characteristics of the gain of Stokes pulses in single-mode optical fibres by stimulated Brillouin scattering (SBS) of monochromatic and nonmonochromatic pump signals have been investigated by numerical simulation using a spectral approach. Conditions under which 'slow light' (caused by a group delay) can be implemented are found (it is reasonable to apply this term to a process in which a pulse is delayed with conservation of its shape). The plane-wave interaction model is shown to describe adequately the dynamics of this process in single-mode fibres. A number of gain modes are investigated for Stokes pulses with different time structures upon monochromatic and nonmonochromatic excitation. A new data transfer technique is proposed, which is based on the conversion of stepwise phase modulation of the input Stokes signal into amplitude modulation of the output signal.

  4. Applications and Optimization of Optical Time Lenses based on Four-Wave Mixing in Highly Nonlinear Fibre

    DEFF Research Database (Denmark)

    Lillieholm, Mads

    2017-01-01

    Optical Fourier transformations enabled by the versatile time lens (quadratic phase modulator), have been demonstrated for numerous optical signal processing applications. Applications include ultrafast optical oscilloscopes, high resolution spectralanalysers, and the processing of ultrahigh......-speed communication signals, to enable e.g. such varied applications as phase regeneration for wavelength-division multiplexing (WDM) signals, conversion between spectrally efficient formats and receivers with reduced complexity for advanced optical multiplexing formats. Four-wave mixing (FWM) is showing promise...... as a method to implement time lenses, for its ability to impart a parabolic phase profile with high fidelity, and to transparently process and preserve arbitrary amplitude and phase information at ultrahigh data rates. Many time lens demonstrations have been based on FWM with linearly chirped pump pulses...

  5. On the possibility of developing incoherent fibre-optic data transmission systems based on signal spectral coding with matched acousto-optical filters

    International Nuclear Information System (INIS)

    Proklov, Valerii V; Byshevski-Konopko, O A; Grigorievski, V I

    2013-01-01

    The scheme is suggested for developing the optical communication line based on the principle of code division of multiple access with matched acousto-optical filters and a 16-bit long Walsh sequence. Results of modelling show that such a line can operate if adjacent spectral lines are separated by at least double the Rayleigh criterion. (optical information transmission)

  6. Monitoring Pre-Stressed Composites Using Optical Fibre Sensors

    Directory of Open Access Journals (Sweden)

    Sriram Krishnamurthy

    2016-05-01

    Full Text Available Residual stresses in fibre reinforced composites can give rise to a number of undesired effects such as loss of dimensional stability and premature fracture. Hence, there is significant merit in developing processing techniques to mitigate the development of residual stresses. However, tracking and quantifying the development of these fabrication-induced stresses in real-time using conventional non-destructive techniques is not straightforward. This article reports on the design and evaluation of a technique for manufacturing pre-stressed composite panels from unidirectional E-glass/epoxy prepregs. Here, the magnitude of the applied pre-stress was monitored using an integrated load-cell. The pre-stressing rig was based on a flat-bed design which enabled autoclave-based processing. A method was developed to end-tab the laminated prepregs prior to pre-stressing. The development of process-induced residual strain was monitored in-situ using embedded optical fibre sensors. Surface-mounted electrical resistance strain gauges were used to measure the strain when the composite was unloaded from the pre-stressing rig at room temperature. Four pre-stress levels were applied prior to processing the laminated preforms in an autoclave. The results showed that the application of a pre-stress of 108 MPa to a unidirectional [0]16 E-glass/913 epoxy preform, reduced the residual strain in the composite from −600 µε (conventional processing without pre-stress to approximately zero. A good correlation was observed between the data obtained from the surface-mounted electrical resistance strain gauge and the embedded optical fibre sensors. In addition to “neutralising” the residual stresses, superior axial orientation of the reinforcement can be obtained from pre-stressed composites. A subsequent publication will highlight the consequences of pres-stressing on fibre alignment, the tensile, flexural, compressive and fatigue performance of unidirectional E

  7. Monitoring Pre-Stressed Composites Using Optical Fibre Sensors.

    Science.gov (United States)

    Krishnamurthy, Sriram; Badcock, Rodney A; Machavaram, Venkata R; Fernando, Gerard F

    2016-05-28

    Residual stresses in fibre reinforced composites can give rise to a number of undesired effects such as loss of dimensional stability and premature fracture. Hence, there is significant merit in developing processing techniques to mitigate the development of residual stresses. However, tracking and quantifying the development of these fabrication-induced stresses in real-time using conventional non-destructive techniques is not straightforward. This article reports on the design and evaluation of a technique for manufacturing pre-stressed composite panels from unidirectional E-glass/epoxy prepregs. Here, the magnitude of the applied pre-stress was monitored using an integrated load-cell. The pre-stressing rig was based on a flat-bed design which enabled autoclave-based processing. A method was developed to end-tab the laminated prepregs prior to pre-stressing. The development of process-induced residual strain was monitored in-situ using embedded optical fibre sensors. Surface-mounted electrical resistance strain gauges were used to measure the strain when the composite was unloaded from the pre-stressing rig at room temperature. Four pre-stress levels were applied prior to processing the laminated preforms in an autoclave. The results showed that the application of a pre-stress of 108 MPa to a unidirectional [0]16 E-glass/913 epoxy preform, reduced the residual strain in the composite from -600 µε (conventional processing without pre-stress) to approximately zero. A good correlation was observed between the data obtained from the surface-mounted electrical resistance strain gauge and the embedded optical fibre sensors. In addition to "neutralising" the residual stresses, superior axial orientation of the reinforcement can be obtained from pre-stressed composites. A subsequent publication will highlight the consequences of pres-stressing on fibre alignment, the tensile, flexural, compressive and fatigue performance of unidirectional E-glass composites.

  8. Nuisance alarm suppression techniques for fibre-optic intrusion detection systems

    Science.gov (United States)

    Mahmoud, Seedahmed S.; Visagathilagar, Yuvaraja; Katsifolis, Jim

    2012-02-01

    The suppression of nuisance alarms without degrading sensitivity in fibre-optic intrusion detection systems is important for maintaining acceptable performance. Signal processing algorithms that maintain the POD and minimize nuisance alarms are crucial for achieving this. A level crossings algorithm is presented for suppressing torrential rain-induced nuisance alarms in a fibre-optic fence-based perimeter intrusion detection system. Results show that rain-induced nuisance alarms can be suppressed for rainfall rates in excess of 100 mm/hr, and intrusion events can be detected simultaneously during rain periods. The use of a level crossing based detection and novel classification algorithm is also presented demonstrating the suppression of nuisance events and discrimination of nuisance and intrusion events in a buried pipeline fibre-optic intrusion detection system. The sensor employed for both types of systems is a distributed bidirectional fibre-optic Mach Zehnder interferometer.

  9. Detection of high level carbon dioxide emissions using a compact optical fibre based mid-infrared sensor system for applications in environmental pollution monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Muda, R; Lewis, E; O' Keeffe, S; Dooly, G; Clifford, J, E-mail: razali.muda@ul.i [Optical Fibre Sensors Research Centre, Electronic and Computer Engineering Department, University of Limerick (Ireland)

    2009-07-01

    A novel and highly compact optical fibre based sensor system for measurement of high concentrations CO{sub 2} gas emissions in modern automotive exhaust is presented. The sensor system works based on the principle of open-path direct absorption spectroscopy in the mid-infrared wavelength range. The sensor system, which comprises low cost components and is compact in design, is well suited for applications in monitoring CO{sub 2} emissions from the exhaust of automotive vehicles. The sensor system utilises calcium fluoride (CaF{sub 2}) lenses and a narrow band pass (NBP) filter for detection of CO{sub 2} gas. The response of the sensor to high concentrations of CO{sub 2} gas is presented and the result is compared with that of a commercial flue gas analyser. The sensor shows response times of 5.2s and demonstrates minimal susceptibility to cross interferences of other gases present in the exhaust system.

  10. Large area laser scanning optical resolution photoacoustic microscopy using a fibre optic sensor.

    Science.gov (United States)

    Allen, Thomas J; Ogunlade, Olumide; Zhang, Edward; Beard, Paul C

    2018-02-01

    A laser scanning optical resolution photoacoustic microscopy (LS OR-PAM) system based on a stationary fibre optic sensor is described. The sensor comprises an optically resonant interferometric polymer cavity formed on the tip of a rounded single mode optical fibre. It provides low noise equivalent pressure (NEP = 68.7 Pa over a 20 MHz measurement bandwidth), a broad bandwidth that extends to 80 MHz and a near omnidirectional response. The latter is a significant advantage, as it allows large areas (>1cm 2 ) to be imaged without the need for translational mechanical scanning offering the potential for fast image acquisition. The system provides a lateral resolution of 8 µm, an axial resolution of 21 µm, and a field of view up to 10 mm × 10 mm. To demonstrate the system, in vivo 3D structural images of the microvasculature of a mouse ear were obtained, showing single capillaries overlaying larger vessels as well as functional images revealing blood oxygen saturation.

  11. Optoelectronic line transmission an introduction to fibre optics

    CERN Document Server

    Tricker, Raymond L

    2013-01-01

    Optoelectronic Line Transmission: An Introduction to Fibre Optics presents a basic introduction as well as a background reference manual on fiber optic transmission. The book discusses the basic principles of optical line transmission; the advantages and disadvantages of optical fibers and optoelectronic signalling; the practical applications of optoelectronics; and the future of optoelectronics. The text also describes the theories of optical line transmission; fibers and cables for optical transmission; transmitters including light-emitting diodes and lasers; and receivers including photodi

  12. Quantifying uncertainty contributions for fibre optic power meter calibrations

    CSIR Research Space (South Africa)

    Nel, M

    2009-09-01

    Full Text Available A fibre optic power meter calibration has several uncertainty contributors associated with it. In order to assign a realistic uncertainty to the calibration result it is necessary to realistically estimate the magnitude of each uncertainty...

  13. Dynamic Analysis with Fibre Optic Sensors for Structural Health Monitoring

    National Research Council Canada - National Science Library

    Paolozzi, Antonio; Gasbarri, Paolo

    2006-01-01

    Structural Health Monitoring (SHM) is a new frontier of non destructing testing. Often SHM is associated with fibre optic sensors whose signals can be used to identify the structure and consequently its damage...

  14. Fibre optic sensors in pressurized water reactor alternators; Des capteurs a fibres optiques dans les alternateurs des REP

    Energy Technology Data Exchange (ETDEWEB)

    Favennec, J.M.; Piguet, M.

    1994-12-31

    Measurement in the electrical engine environment (alternator, transformer...) is identified as one of the two main applications of fibre optic sensors within EDF; the other application niche is the monitoring of civil works (dams, containment building of nuclear reactors...). At the EDF Research and Development Division, temperature and vibration fibre optic sensors were evaluated by the Metrology Service, since their use is under consideration for alternator monitoring. For alternator stator thermal monitoring, the BERTIN company developed a fibre optic sensor network. The optic coding technique is based on broadband source spectral modulation; the sensors are interrogated sequentially by electronic commutation. For alternator stator vibration monitoring, a fibre optic accelerometer was developed in the frame of a manufacturers and universities consortium supported by the French Research and Technology Ministry. The accelerometer is of cantilever beam type and its networking is possible by chromatic multiplexing. The Metrology Service evaluated these temperature and vibration sensors in order to verify their metrological characteristics (bias error, hysteresis, repeatability, resolution, noise, amplitude linearity, response time, frequency response, etc.) and to test their behaviour in harsh alternator environmental conditions (pressure, vibrations and temperature). Ageing and accidental condition resistance tests were also carried out. Temperature sensor test results were very satisfactory. An eight-sensor BERTIN prototype was installed on the Tricastin 1 alternator during the september 1993 nuclear station periodic stop. On the contrary, the accelerometers presented deficient metrological characteristics (shorter span than foreseen, low repeatability...). They need some improvements and could not be installed on alternators. (authors). 5 refs., 8 figs.

  15. Photonic Crystal Fibres: A New Calss of Optical Waveguides

    DEFF Research Database (Denmark)

    Broeng, Jes; Mogilevstev, D.; Barkou, Stig Eigil

    1999-01-01

    . With an emphasis on the applicational aspects of the fibers, we study their single-mode operation, bending losses, and dispersion properties. While exhibiting certain unique properties, the high-index core photonic crystal fibres share many common features with conventional optical fibers, attributed...... to an operation based on the well-known mechanism of total internal reflection. Fundamentally different from all high-index core fibers, in this work we demostrate a novel type of optical waveguide, operating truly by the photonic bandgap effect. The novel fiber has an improved photonic crystal cladding...... are fundamental in the field of photonic bandgap guidance, and this new class of optical waveguides is, therefore, expected to be of future interest to a large variety of research areas....

  16. RT Self-assembly of Silica Nanoparticles on Optical Fibres

    DEFF Research Database (Denmark)

    Canning, John; Lindoy, Lachlan; Huyang, George

    2013-01-01

    The room temperature deposition of self-assembling silica nanoparticles onto D-shaped optical fibres x201c;D-fibrex201d;), drawn from milled preforms fabricated by modified chemical vapor deposition, is studied and preliminary results reported here.......The room temperature deposition of self-assembling silica nanoparticles onto D-shaped optical fibres x201c;D-fibrex201d;), drawn from milled preforms fabricated by modified chemical vapor deposition, is studied and preliminary results reported here....

  17. Fibre-Bragg-grating writing in single-mode optical fibres by UV femtosecond pulses

    International Nuclear Information System (INIS)

    Zagorul'ko, K A; Kryukov, P G; Dianov, Evgenii M; Dragomir, A; Nikogosyan, D N

    2003-01-01

    Fibre-Bragg-grating writing in single-mode optical fibres by the phase-mask method using 220-fs, 264-nm UV pulses of intensity 31 - 77 GW cm -2 is reported for the first time. The achieved degree of modulation of the photoinduced refractive index was 1.9 x 10 -3 in an H 2 -loaded SMF-28 telecommunication fibre and 1.1 x 10 -3 in a H 2 -free Nufern GF1 fibre. The dependence of the induced refractive index on the intensity for the same irradiation fluences in the case of the H 2 -loaded SMF-28 fibre shows that the refractive index is induced due to nonlinear absorption. (letters)

  18. Polarisation maintaining fibre with pure silica core and two depressed claddings for fibre optic gyroscope

    Science.gov (United States)

    Kurbatov, A. M.; Kurbatov, R. A.; Voloshin, V. V.; Vorob'ev, I. L.; Kolosovsky, A. O.

    2016-12-01

    Polarisation maintaining (PM) fibre is described with pure silica core and two depressed claddings for fibre optic gyro (FOG) sensing coil. Detailed mathematical simulation is presented by supermodes method, which is extremely necessary for such fibre. Simulation is fulfilled by frequency domain finite difference method (FDFDM), taking into account all details of realistic index profile with stress applying parts, while the leakage/bend loss occur in the region with complex index, surrounding the fibre. Cutoff and small bend loss are theoretically predicted and experimentally measured with excellent agreement between theory and experiment. Polarisation maintaining ability is measured in the form of conventional h-parameter (7.1·10-6 1/m) for 90-μm diameter fibre with birefringence value only 3.9·10-4.

  19. Optical fibres in the radiation environment of CERN

    Science.gov (United States)

    Guillermain, E.

    2017-11-01

    CERN, the European Organization for Nuclear Research (in Geneva, Switzerland), is home to a complex scientific instrument: the 27-kilometre Large Hadron Collider (LHC) collides beams of high-energy particles at close to the speed of light. Optical fibres are widely used at CERN, both in surface areas (e.g. for inter-building IT networks) and in the accelerator complex underground (e.g. for cryogenics, vacuum, safety systems). Optical fibres in the accelerator are exposed to mixed radiation fields (mainly composed of protons, pions, neutrons and other hadrons, gamma rays and electrons), with dose rates depending on the particular installation zone, and with radiation levels often significantly higher than those encountered in space. In the LHC and its injector chain radiation levels range from relatively low annual doses of a few Gy up to hundreds of kGy. Optical fibres suffer from Radiation Induced Attenuation (RIA, expressed in dB per unit length) that affect light transmission and which depends on the irradiation conditions (e.g. dose rate, total dose, temperature). In the CERN accelerator complex, the failure of an optical link can affect the proper functionality of control or monitoring systems and induce the interruption of the accelerator operation. The qualification of optical fibres for installation in critical radiation areas is therefore crucial. Thus, all optical fibre types installed in radiation areas at CERN are subject to laboratory irradiation tests, in order to evaluate their RIA at different total dose and dose rates. This allows the selection of the appropriate optical fibre type (conventional or radiation resistant) compliant with the requirements of each installation. Irradiation tests are performed in collaboration with Fraunhofer INT (irradiation facilities and expert team in Euskirchen, Germany). Conventional off-the-shelf optical fibres can be installed for optical links exposed to low radiation levels (i.e. annual dose typically below few

  20. Fibre optic cables for the ALICE experiment

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    These thin fibres will transmit the signal received in detectors at the ALICE experiment when it starts up with the LHC in 2008. The analogue signals produced in the detectors are first converted into digital pulse, which are transported in light down such fibres. Computers then read this digital signal to produce the final set of data.

  1. Fibre Optical Parametric Amplification in Defect Bragg Fibres with Zero Dispersion Slow Light Effect

    International Nuclear Information System (INIS)

    Li, Xiao; Wei, Zhang; Yi-Dong, Huang; Jiang-De, Peng; Hong, Zhao; Ke-Wu, Yang

    2008-01-01

    Nonlinearity enhancement by slow light effect and strong light confinement in defect Bragg fibres is demonstrated and analysed in applications of fibre optical parametric amplifiers. Broadband low group velocity and zero dispersion as well as the strong light confinement by band gap enhances the nonlinear coefficient up to more than one order than the conventional high nonlinear fibres. Moreover, the zero dispersion wavelength of coupled core mode can be designed arbitrarily, under which the phase-matching bandwidth of the nonlinear process can be extended. (fundamental areas of phenomenology (including applications))

  2. Rayleigh scatter based order of magnitude increase in distributed temperature and strain sensing by simple UV exposure of optical fibre.

    Science.gov (United States)

    Loranger, Sébastien; Gagné, Mathieu; Lambin-Iezzi, Victor; Kashyap, Raman

    2015-06-16

    We present a technique to improve signal strength, and therefore sensitivity in distributed temperature and strain sensing (DTSS) using Frequency domain Rayleigh scatter. A simple UV exposure of a hydrogen loaded standard SMF-28 fibre core is shown to enhance the Rayleigh back-scattered light dramatically by ten-fold, independent of the presence of a Bragg grating, and is therefore created by the UV exposure alone. This increase in Rayleigh back-scatter allows an order-of-magnitude increase in temperature and strain resolution for DTSS compared to un-exposed SMF-28 fibre used as a sensing element. This enhancement in sensitivity is effective for cm range or more sensor gauge length, below which is the theoretical cross-correlation limit. The detection of a 20 mK temperature rise with a spatial resolution of 2 cm is demonstrated. This gain in sensitivity for SMF-28 is compared with a high Ge doped photosensitive fibre with a characteristically high NA. For the latter, the UV enhancement is also present although of lower amplitude, and enables an even lower noise level for sensing, due to the fibre's intrinsically higher Rayleigh scatter signal.

  3. Low-cost monitoring of the wavelength difference of two transmitters for two-way time transfer over optical fibre

    OpenAIRE

    Slavík, Radan; Vojtěch, Josef; Smotlacha, Vladimir

    2015-01-01

    Accurate time transfer is routinely performed using GPS, however an order of magnitude better accuracy can be achieved when signal transfer over optical fibres is used (e.g., in [1], fibre transfer over 73 km with <100 ps precision was achieved as compared to <700 ps for the GPS-based system). Unfortunately, the propagation delay through an optical fibre changes due to temperature variation. This is commonly compensated for by transferring the time information bi-directionally over a si...

  4. Contributed Review: Distributed optical fibre dynamic strain sensing.

    Science.gov (United States)

    Masoudi, Ali; Newson, Trevor P

    2016-01-01

    Extensive research on Brillouin- and Raman-based distributed optical fibre sensors over the past two decades has resulted in the commercialization of distributed sensors capable of measuring static and quasi-static phenomena such as temperature and strain. Recently, the focus has been shifted towards developing distributed sensors for measurement of dynamic phenomena such as dynamic strain and sound waves. This article reviews the current state of the art distributed optical fibre sensors capable of quantifying dynamic vibrations. The most important aspect of Rayleigh and Brillouin scattering processes which have been used for distributed dynamic measurement are studied. The principle of the sensing techniques used to measure dynamic perturbations are analyzed followed by a case study of the most recent advances in this field. It is shown that the Rayleigh-based sensors have longer sensing range and higher frequency range, but their spatial resolution is limited to 1 m. On the other hand, the Brillouin-based sensors have shown a higher spatial resolution, but relatively lower frequency and sensing ranges.

  5. Fibre-Optic Semiconductor Temperature Gage

    Science.gov (United States)

    Sharma, M.

    1982-01-01

    "Safe" temperature gage for explosive liquids is based on optical transmission. Semiconductor crystal inserted between input and output optical fibers is temperature-sensing element in a new approach to measuring temperature of cryogens. Since no electrical components are immersed in liquid, new sensor minimizes danger of electrically ignited explosions in hazardous cryogens such as oxygen and hydrogen. Gage also useful for handling noncryogenic liquids in aircraft, automobiles, boats and water tanks.

  6. Recent Improvement of Medical Optical Fibre Pressure and Temperature Sensors

    Directory of Open Access Journals (Sweden)

    Sven Poeggel

    2015-07-01

    Full Text Available This investigation describes a detailed analysis of the fabrication and testing of optical fibre pressure and temperature sensors (OFPTS. The optical sensor of this research is based on an extrinsic Fabry–Perot interferometer (EFPI with integrated fibre Bragg grating (FBG for simultaneous pressure and temperature measurements. The sensor is fabricated exclusively in glass and with a small diameter of 0.2 mm, making it suitable for volume-restricted bio-medical applications. Diaphragm shrinking techniques based on polishing, hydrofluoric (HF acid and femtosecond (FS laser micro-machining are described and analysed. The presented sensors were examined carefully and demonstrated a pressure sensitivity in the range of \\(s_p\\ = 2–10 \\(\\frac{\\text{nm}}{\\text{kPa}}\\ and a resolution of better than \\(\\Delta P\\ = 10 Pa protect (0.1 cm H\\(_2\\O. A static pressure test in 38 cmH\\(_2\\O shows no drift of the sensor in a six-day period. Additionally, a dynamic pressure analysis demonstrated that the OFPTS never exceeded a drift of more than 130 Pa (1.3 cm H\\(_2\\O in a 12-h measurement, carried out in a cardiovascular simulator. The temperature sensitivity is given by \\(k=10.7\\ \\(\\frac{\\text{pm}}{\\text{K}}\\, which results in a temperature resolution of better than \\(\\Delta T\\ = 0.1 K. Since the temperature sensing element is placed close to the pressure sensing element, the pressure sensor is insensitive to temperature changes.

  7. Recent Improvement of Medical Optical Fibre Pressure and Temperature Sensors.

    Science.gov (United States)

    Poeggel, Sven; Duraibabu, Dineshbabu; Kalli, Kyriacos; Leen, Gabriel; Dooly, Gerard; Lewis, Elfed; Kelly, Jimmy; Munroe, Maria

    2015-07-13

    This investigation describes a detailed analysis of the fabrication and testing of optical fibre pressure and temperature sensors (OFPTS). The optical sensor of this research is based on an extrinsic Fabry-Perot interferometer (EFPI) with integrated fibre Bragg grating (FBG) for simultaneous pressure and temperature measurements. The sensor is fabricated exclusively in glass and with a small diameter of 0.2 mm, making it suitable for volume-restricted bio-medical applications. Diaphragm shrinking techniques based on polishing, hydrofluoric (HF) acid and femtosecond (FS) laser micro-machining are described and analysed. The presented sensors were examined carefully and demonstrated a pressure sensitivity in the range of sp = 2-10 nm/kPa and a resolution of better than ΔP = 10 Pa protect (0.1 cm H2O). A static pressure test in 38 cm H2O shows no drift of the sensor in a six-day period. Additionally, a dynamic pressure analysis demonstrated that the OFPTS never exceeded a drift of more than 130 Pa (1.3 cm H2O) in a 12-h measurement, carried out in a cardiovascular simulator. The temperature sensitivity is given by k = 10.7 pm/K, which results in a temperature resolution of better than ΔT = 0.1 K. Since the temperature sensing element is placed close to the pressure sensing element, the pressure sensor is insensitive to temperature changes.

  8. Fibre Optic Sensors Using Adiabatically Tapered Single Mode Fibres

    Science.gov (United States)

    1994-02-01

    Membrane L!2ht Scurce ,ettor ([3Iar~nca] Property ImmobilIzatIon Optical Flba UAnpLl Dynamoc Range SeMfle Su art Arran ramene ,-t n i esuaorn Tlrrm...8217Solution-deposited thin films as passive and active light guides’, Applied Optics, 1972, 11, No 2, pp. 428-34. 397. Urbano , E. , H. Offenbacher, O.S...Chimica Acta, 1988, 208, pp. 53-8. 427. Wolfbeis, O.S., E. Urbano , ’A fluorimetric, heavy-metal-free method for the analysis of chlorine, bromine, and

  9. Design of dual-mode optical fibres for the FTTH applications

    Science.gov (United States)

    Chen, Ming-Yang; Li, Yu-Rong; Zhang, Yin; Zhu, Yuan-Feng; Zhang, Yong-Kang; Zhou, Jun

    2011-01-01

    We present in this article a proposal and design for dual-mode optical fibres for fibre-to-the-home applications. High-order modes in the fibre can be effectively suppressed by the connection of the fibre with standard single-mode optical fibres at the two ends of the fibre. The alignment tolerance at the splicing process is presented. In particular, a low bending loss operation with low splice loss is demonstrated using the proposed technique.

  10. Fibres reinforced dentures investigated with en-face optical coherence tomography

    Science.gov (United States)

    Negrutiu, Meda L.; Sinescu, Cosmin; Hughes, Michael; Bradu, Adrian; Goguta, Luciana; Rominu, Mihai; Negru, Radu; Podoleanu, Adrian Gh.

    2008-04-01

    The complete dentures are currently made using different technologies. In order to avoid deficiencies of the prostheses made using the classical technique, several alternative procedures have been devised. In order to enhance the mechanical strength, complete denture bases are reinforced with fibres. Their material and structure vary wildly, which makes the investigation difficult. In this study, optical coherence tomography (OCT) is evaluated as a possible non-invasive technique to assess the biomechanical behaviour of the reinforcing fibres. OCT images demonstrate structural defects between fibres and the acrylic material in all dentures bases investigated. We conclude that OCT can successfully be used as a noninvasive analysis method.

  11. Waveguidance by the photonic bandgap effect in optical fibres

    DEFF Research Database (Denmark)

    Broeng, Jes; Søndergaard, Thomas; Barkou, Stig Eigil

    1999-01-01

    technology for such photonic bandgap (PBG) waveguides is in optical fibre configurations. These new fibres can be classified in a fundamentally different way to all optical waveguides and possess radically different guiding properties due to PBG guidance, as opposed to guidance by total internal refelction....... In this paper we summarize and review our theoretical work demonstrating the underlying physical principles of PBG guiding optical fibres and discuss some of their unique waveguiding properties.......Photonic crystals form a new class of intriguing building blocks to be utilized in future optoelectronics and electromagnetics. One of the most exciting possiblilties offered by phtonic crystals is the realization of new types of electromagnetic waveguides. In the optical domain, the most mature...

  12. Suppression of phase-induced intensity noise in fibre optic delay line signal processors using an optical phase modulation technique.

    Science.gov (United States)

    Chan, Erwin H W

    2010-10-11

    A technique that can suppress the dominant phase-induced intensity noise in fibre optic delay line signal processors is presented. It is based on phase modulation of the optical carrier to distribute the phase noise at the information band into a high frequency band which can be filtered out. This technique is suitable for suppressing the phase noise in various delay line structures and for integrating in the conventional fibre optic links. It can also suppress the coherent interference effect at the same time. A model for predicting the amount of phase noise reduction in various delay line structures using the optical phase modulation technique is presented for the first time and is experimentally verified. Experimental results demonstrate the technique can achieve a large phase noise reduction in various fibre optic delay line signal processors.

  13. Laser Cutting of CFRP with a Fibre Guided High Power Nanosecond Laser Source - Influence of the Optical Fibre Diameter on Quality and Efficiency

    Science.gov (United States)

    Bluemel, S.; Bastick, S.; Staehr, R.; Jaeschke, P.; Suttmann, O.; Overmeyer, L.

    For the development of a robot based laser cutting process of automotive 3D parts consisting of carbon fibre reinforced plastics (CFRP), investigations with a newly developed fibre guided nanosecond pulsed laser with an average power of PL = 1.5 kW were conducted. In order to investigate the best combination of quality and process time 2 different optical fibres were used, with diameters of df = 400 μm and df = 600 μm. The main differences between the two setups are the resulting focal diameter and the maximum available pulse energy up to EP = 80 mJ. In a first instance, a comparable investigation was performed with both fibres for a constant pulse overlap. For each fibre the minimum required line energy was investigated and cuts were performed, distributed over the complete parameter range of the laser source. The influences of the fibre diameter on the quality and efficiency of the cutting process are summarized and discussed.

  14. Optical fibre probes in the measurement of scattered light ...

    Indian Academy of Sciences (India)

    2014-01-08

    Jan 8, 2014 ... Home; Journals; Pramana – Journal of Physics; Volume 82; Issue 1. Optical fibre probes in the measurement of scattered light: Application for sensing turbidity ... Here we present our work on the design and realization of optrodes for the measurement of scattered light from liquid samples. Optical properties ...

  15. A new fibre optic sensor for respiratory monitoring.

    Science.gov (United States)

    Davis, C; Mazzolini, A; Murphy, D

    1997-12-01

    A new fibre optic plethysmograph has been designed to monitor respiration non invasively. The device incorporates the idea of using thoracic and abdominal belts similar to conventional inductance plethysmography but uses an optical fibre woven into the belts rather than the usual coiled wire. The fibre optic belts incorporate a loop design in the fibre and rely on "macrobending" losses from laser light transmitted down the fibre when the bend radius of the loop changes during respiration. Changes in lung volume are monitored by analysing the relatively large resultant changes in light transmitted through the fibre. The output from the light detector has been interfaced to a computer containing a data acquisition card and the resultant intensity trace is monitored in real time using a virtual instrument created using LabVIEW graphical programming. Preliminary results suggest a highly sensitive system capable of detecting small changes in lung volume using a technique which is not susceptible to electrical noise and which is electrically safe.

  16. Modelling and processing of data from a fibre-optic sensor of vibrations

    International Nuclear Information System (INIS)

    Morawski, R Z; Makowski, P L; Michalik, L; Domanski, A W

    2010-01-01

    A new technique of vibration sensing, based on a polarimetric fibre-optic strain sensor, is presented; it is designed for localisation of multiple sources of disturbances in a broad spectrum without using fibre gratings. A mathematical model of the sensor is used for development of a variational method for estimation of amplitudes of component vibrations on the basis of noisy samples of the voltage at the output of the sensor.

  17. Spectroscopic On-Line Monitoring of Cu/W Contacts Erosion in HVCBs Using Optical-Fibre Based Sensor and Chromatic Methodology.

    Science.gov (United States)

    Wang, Zhixiang; Jones, Gordon R; Spencer, Joseph W; Wang, Xiaohua; Rong, Mingzhe

    2017-03-06

    Contact erosion is one of the most crucial factors affecting the electrical service lifetime of high-voltage circuit breakers (HVCBs). On-line monitoring the contacts' erosion degree is increasingly in demand for the sake of condition based maintenance to guarantee the functional operation of HVCBs. A spectroscopic monitoring system has been designed based upon a commercial 245 kV/40 kA S F 6 live tank circuit breaker with copper-tungsten (28 wt % and 72 wt %) arcing contacts at atmospheric S F 6 pressure. Three optical-fibre based sensors are used to capture the time-resolved spectra of arcs. A novel approach using chromatic methods to process the time-resolved spectral signal has been proposed. The processed chromatic parameters have been interpreted to show that the time variation of spectral emission from the contact material and quenching gas are closely correlated to the mass loss and surface degradation of the plug arcing contact. The feasibility of applying this method to online monitoring of contact erosion is indicated.

  18. Flat knitting of a light emitting textile with optical fibres

    DEFF Research Database (Denmark)

    Heimdal, Elisabeth Jacobsen

    2009-01-01

    in the practice of weft knitting. This paper is about the experimental product development of a light radiating textile lamp in which optical fibres are used as the only illumination source. The lampshade is produced on an electronic flat knitting machine with special equipment suitable for the feeding of yarn...... with high stiffness. The work was divided in two parts: exploring the possibilities to knit the desired shape on one hand and experimenting about knitting with optical fibres as a weft insertion on the other hand. The method is an inductive approach; a literature survey, information from suppliers...... with stiff and brittle optical fibres therefore the paper ends with a discussion with suggestions of how to overcome these challenges....

  19. High-throughput imaging of self-luminous objects through a single optical fibre.

    Science.gov (United States)

    Barankov, Roman; Mertz, Jerome

    2014-11-20

    Imaging through a single optical fibre offers attractive possibilities in many applications such as micro-endoscopy or remote sensing. However, the direct transmission of an image through an optical fibre is difficult because spatial information is scrambled upon propagation. We demonstrate an image transmission strategy where spatial information is first converted to spectral information. Our strategy is based on a principle of spread-spectrum encoding, borrowed from wireless communications, wherein object pixels are converted into distinct spectral codes that span the full bandwidth of the object spectrum. Image recovery is performed by numerical inversion of the detected spectrum at the fibre output. We provide a simple demonstration of spread-spectrum encoding using Fabry-Perot etalons. Our technique enables the two-dimensional imaging of self-luminous (that is, incoherent) objects with high throughput in principle independent of pixel number. Moreover, it is insensitive to fibre bending, contains no moving parts and opens the possibility of extreme miniaturization.

  20. Comparison of Numerical Modelling of Degradation Mechanisms in Single Mode Optical Fibre Using MATLAB and VPIphotonics

    Directory of Open Access Journals (Sweden)

    Jana Sajgalikova

    2015-01-01

    Full Text Available Mathematical models for description of physical phenomena often use the statistical description of the individual phenomena and solve those using suitable methods. If we want to develop numerical model of optical communication system based on transmission through single mode optical fibres, we need to consider whole series of phenomena that affect various parts of the system. In the single-mode optical fibre we often encounter influence of chromatic dispersion and nonlinear Kerr effects. By observing various different degradation mechanisms, every numerical model should have its own limits, which fulfil more detailed specification. It is inevitable to consider them in evaluation. In this paper, we focus on numerical modelling of degradation mechanisms in single-mode optical fibre. Numerical solution of non-linear Schroedinger equation is performed by finite difference method applied in MATLAB environment and split-step Fourier method, which is implemented by VPIphotonics software.

  1. Exploiting multimode waveguides for pure fibre based fluorescence imaging

    Science.gov (United States)

    Čižmár, TomáÅ.¡; Dholakia, Kishan

    2013-03-01

    There has been an immense drive in modern microscopy towards miniaturisation and _bre based technology. This has been necessitated by the need to access hostile or difficult environments particulalrly in-situ and in-vivo. Strategies to date have included the use of specialist fibres and miniaturised scanning systems accompanied by ingenious microfabricated lenses. In parallel recent studies of randomized light fields and their holographic control opened up new ways for imaging. We present a novel approach for this field by utilising disordered light within a standard multimode optical fibre for minimally invasive lenseless microscopy and optical mode conversion. We demonstrate scanning uorescence microscopy at acquisition rates allowing observation of dynamic processes such as Brownian motion of mesoscopic particles. As the sample plane can be defined at any distance from the fibre facet, we eliminate the need for complex or elaborate focusing optics (e.g. miniaturized objectives, GRIN lenses) and instead reconfigure the system dynamically to image different axial planes. Furthermore, we show how such control can realise a new form of mode converter and generate various types of advanced light fields such as propagation-invariant beams and optical vortices. These may be useful for future fibre based implementations of super-resolution or light sheet microscopy. To the best of our knowledge, this technology represents the narrowest possible image guiding system based on light propagation.

  2. CONFERENCE NOTE: CETO—Centro de Ciências e Tecnologias Opticas, Trends in Optical Fibre Metrology and Standards

    Science.gov (United States)

    1994-01-01

    Summer School, 27 June to 8 July 1994, Viana do Castelo, Hotel do Parque, Portugal Optical fibres, with their extremely low transmission loss, untapped bandwidth and controllable dispersion, dominate a broad range of technologies in which applications must respond to the increasing constraints of today's specifications as well as envisage future requirements. Optical fibres dominate communications systems. In the area of sensors, fibre optics will be fully exploited for their immunity to EMI, their high sensitivity and their large dynamic range. The maturity of single mode optical technology has led to intensive R&D of a range of components based on the advantages of transmission characteristics and signal processing. Specifications and intercompatibility requests for the new generation of both analogue and digital fibre optical components and systems has created a demand for sophisticated measuring techniques based on unique and complex instruments. In recent years there has been a signification evolution in response to the explosion of applications and the tightening of specifications. These developments justify a concerted effort to focus on trends in optical fibre metrology and standards. Objective The objective of this school is to provide a progressive and comprehensive presentation of current issues concerning passive and active optical fibre characterization and measurement techniques. Passive fibre components support a variety of developments in optical fibre systems and will be discussed in terms of relevance and standards. Particular attention will be paid to devices for metrological purposes such as reference fibres and calibration artefacts. The characterization and testing of optical fibre amplifiers, which have great potential in telecommunications, data distribution networks and as a system part in instrumentation, will be covered. Methods of measurement and means of calibration with traceability will be discussed, together with the characterization

  3. A comparison of k-NN, backpropagation, and self-organising map classification methods using an optical fibre based sensor system utilised in an industrial large scale oven

    Science.gov (United States)

    Sheridan, Cormac; O'Farrell, Marion; Lewis, Elfed; Lyons, William B.; Flanagan, Colin; Jackman, Nick

    2005-06-01

    This paper reports on three methods of classifying the spectral data from an optical fibre based sensor system as used in the food industry. The first method uses a feed-forward back-propagation Artificial Neural Network; the second method involves using Kohonen Self-Organising Maps while the third method is k-Nearest Neighbour analysis. The sensor monitors the food colour online as the food cooks by examining the reflected light from both the surface and the core of the product. The combination of using Principal Component Analysis and Backpropagation Neural Networks has been successfully investigated previously. In this paper, results obtained using all three classifiers are presented and compared. The Principal Components used to train each classifier are evaluated from data that generate a "colourscale" comprising six colour classifications. This scale has been developed to allow several products of similar colour to be tested using a single network that had been trained using the colourscale. The results presented show that both the neural network and the Self-Organising Map approach perform comparably, while the k-NN method tested under-performs the other two.

  4. Dynamic terahertz spectroscopy of gas molecules mixed with unwanted aerosol under atmospheric pressure using fibre-based asynchronous-optical-sampling terahertz time-domain spectroscopy

    Science.gov (United States)

    Hsieh, Yi-Da; Nakamura, Shota; Abdelsalam, Dahi Ghareab; Minamikawa, Takeo; Mizutani, Yasuhiro; Yamamoto, Hirotsugu; Iwata, Tetsuo; Hindle, Francis; Yasui, Takeshi

    2016-06-01

    Terahertz (THz) spectroscopy is a promising method for analysing polar gas molecules mixed with unwanted aerosols due to its ability to obtain spectral fingerprints of rotational transition and immunity to aerosol scattering. In this article, dynamic THz spectroscopy of acetonitrile (CH3CN) gas was performed in the presence of smoke under the atmospheric pressure using a fibre-based, asynchronous-optical-sampling THz time-domain spectrometer. To match THz spectral signatures of gas molecules at atmospheric pressure, the spectral resolution was optimized to 1 GHz with a measurement rate of 1 Hz. The spectral overlapping of closely packed absorption lines significantly boosted the detection limit to 200 ppm when considering all the spectral contributions of the numerous absorption lines from 0.2 THz to 1 THz. Temporal changes of the CH3CN gas concentration were monitored under the smoky condition at the atmospheric pressure during volatilization of CH3CN droplets and the following diffusion of the volatilized CH3CN gas without the influence of scattering or absorption by the smoke. This system will be a powerful tool for real-time monitoring of target gases in practical applications of gas analysis in the atmospheric pressure, such as combustion processes or fire accident.

  5. Monitoring food quality using an optical fibre based sensor system—a comparison of Kohonen and back-propagation neural network classification techniques

    Science.gov (United States)

    Sheridan, C.; O'Farrell, M.; Lewis, E.; Lyons, W. B.; Flanagan, C.; Jackman, N.

    2006-02-01

    This paper reports on two methods of classifying the spectral data from an optical fibre based sensor system as used in the food industry. The first method uses a feed-forward back-propagation artificial neural network while the second method involves using Kohonen self-organizing maps. The sensor monitors the food colour online as the food cooks by examining the reflected light from both the surface and the core of the product. The combination of using principal component analysis and back-propagation neural networks has been successfully investigated previously. In this paper, results obtained using this method are compared with results obtained using a self-organizing map trained on the principal components. The principal components used to train both classifiers are ordered in a 'colourscale'—a scale developed to allow several products of similar colour to be tested using a single network that had been trained using the colourscale. The results presented show that both classifiers perform well, and that any differences that arise occur at the boundaries of the classes.

  6. Dynamic terahertz spectroscopy of gas molecules mixed with unwanted aerosol under atmospheric pressure using fibre-based asynchronous-optical-sampling terahertz time-domain spectroscopy.

    Science.gov (United States)

    Hsieh, Yi-Da; Nakamura, Shota; Abdelsalam, Dahi Ghareab; Minamikawa, Takeo; Mizutani, Yasuhiro; Yamamoto, Hirotsugu; Iwata, Tetsuo; Hindle, Francis; Yasui, Takeshi

    2016-06-15

    Terahertz (THz) spectroscopy is a promising method for analysing polar gas molecules mixed with unwanted aerosols due to its ability to obtain spectral fingerprints of rotational transition and immunity to aerosol scattering. In this article, dynamic THz spectroscopy of acetonitrile (CH3CN) gas was performed in the presence of smoke under the atmospheric pressure using a fibre-based, asynchronous-optical-sampling THz time-domain spectrometer. To match THz spectral signatures of gas molecules at atmospheric pressure, the spectral resolution was optimized to 1 GHz with a measurement rate of 1 Hz. The spectral overlapping of closely packed absorption lines significantly boosted the detection limit to 200 ppm when considering all the spectral contributions of the numerous absorption lines from 0.2 THz to 1 THz. Temporal changes of the CH3CN gas concentration were monitored under the smoky condition at the atmospheric pressure during volatilization of CH3CN droplets and the following diffusion of the volatilized CH3CN gas without the influence of scattering or absorption by the smoke. This system will be a powerful tool for real-time monitoring of target gases in practical applications of gas analysis in the atmospheric pressure, such as combustion processes or fire accident.

  7. Principal component analysis for the forensic discrimination of black inkjet inks based on the Vis-NIR fibre optics reflection spectra.

    Science.gov (United States)

    Gál, Lukáš; Oravec, Michal; Gemeiner, Pavol; Čeppan, Michal

    2015-12-01

    Nineteen black inkjet inks of six different brands were examined by fibre optics reflection spectroscopy in Visible and Near Infrared Region (Vis-NIR FORS) directly on paper with a view to achieving good resolution between them. These different inks were tested on nineteen different inkjet printers from three brands. Samples were obtained from prints by reflection probe. Processed reflection spectra in the range 500-1000 nm were used as samples in principal component analysis. Variability between spectra of the same ink obtained from different prints, as well as between spectra of square areas and lines was examined. For both spectra obtained from square areas and lines reference, Principal Component Analysis (PCA) models were created. According to these models, the inkjet inks were divided into clusters. PCA method is able to separate inks containing carbon black as main colorant from the other inks using other colorants. Some spectra were recorded from another piece of printer and used as validation samples. Spectra of validation samples were projected onto reference PCA models. According to position of validation samples in score plots it can be concluded that PCA based on Vis-NIR FORS can reliably differentiate inkjet inks which are included in the reference database. The presented method appears to be a suitable tool for forensic examination of questioned documents containing inkjet inks. Inkjet inks spectra were obtained without extraction or cutting sample with possibility to measure out of the laboratory. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  8. Detection of heavy metal ions in contaminated water by surface plasmon resonance based optical fibre sensor using conducting polymer and chitosan.

    Science.gov (United States)

    Verma, Roli; Gupta, Banshi D

    2015-01-01

    Optical fibre surface plasmon resonance (SPR) based sensor for the detection of heavy metal ions in the drinking water is designed. Silver (Ag) metal and indium tin oxide (ITO) are used for the fabrication of the SPR probe which is further modified with the coating of pyrrole and chitosan composite. The sensor works on the wavelength interrogation technique and is capable of detecting trace amounts of Cd(2+), Pb(2+), and Hg(2+) heavy metal ions in contaminated water. Four types of sensing probes are fabricated and characterised for heavy metal ions out of these pyrrole/chitosan/ITO/Ag coated probe is found to be highly sensitive among all other probes. Further, the cadmium ions bind strongly to the sensing surface than other ions and due to this the sensor is highly sensitive for Cd(2+) ions. The sensor's performance is best for the low concentrations of heavy metal ions and its sensitivity decreases with the increasing concentration of heavy metal ions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Exhibition: Fibre optics, the future is at hand

    CERN Multimedia

    Anaïs Schaeffer

    2012-01-01

    Until 20 June, the Pont de la Machine in Geneva will host an exhibition on fibre optics, sponsored by SIG. CERN, a major user of this technology, was invited to take part with a presentation of some of its scintillating fibre detectors.   The CERN module, designed for the SIG's fibre optics exhibition. Visitors can discover a cosmic ray detector (on the right) and its oscilloscope (on the left), as well as one of the ALFA detector modules (at the back). The Services industriels genevois (SIG), who are in the process of deploying an optical fibre network in Geneva, have decided to showcase this technology with an exhibition entitled “Fibre optique – Le futur à portée de main.” The exhibition, which will be open to the public from 26 April to 20 June, is being held at the Espace ExpoSIG, at the Pont de la Machine in the centre of Geneva. “CERN’s Physics Department was approached by SIG at the start of this year to ...

  10. Self-centring technique for fibre optic microlens mounting using a concave cone-etched fibre

    International Nuclear Information System (INIS)

    Demagh, Nacer-Eddine; Guessoum, Assia; Zegari, Rabah; Gharbi, Tijani

    2011-01-01

    Several techniques of centring a microlens onto the fibre optic end face are studied. In most of them, microsphere lenses are centred with the aid of high-accuracy micro-positioners. This process is complicated with regard to the difficulty in manipulating microsphere lenses. In this paper, a simple and accurate self-centring method for mounting microsphere lenses using a concave cone etched fibre (Demagh et al 2006 Meas. Sci. Technol. 17 119–22) is described. This technique allows the centring of a wide variety of microlens radii, typically 7 µm to over 24 µm. The proposed process, however, is not affected by any spatial positioning control of microspheres. In over 85% of the attempts, the microsphere lenses were centred on the fibre axis to within 0.12 µm

  11. Fibre-top atomic force microscope probe with optical near-field detection capabilities

    NARCIS (Netherlands)

    Tiribilli, B; Margheri, G; Baschieri, P; Menozzi, C; Chavan, D.C.; Iannuzzi, D.

    2011-01-01

    We present a fibre-top probe fabricated by carving a tipped cantilever on an optical fibre, with the tip machined in correspondence of the fibre core. When approached to an optical prism illuminated under total internal reflection conditions, the tip of the cantilever detects the optical tunnelling

  12. Fibre-based imaging: new challenges

    Science.gov (United States)

    Plöschner, Martin; Straka, Branislav; Dholakia, Kishan; Čižmár, TomáÅ.¡

    2015-03-01

    A novel minimally invasive micro-endoscopes utilizing disordered light within a standard multimode optical fibre have been introduced recently. The two most important limitations of this exciting technology are (i) the lack of bending flexibility (transformation matrix is only valid as long as the fibre remains stationary) and (ii) high demands on computational power, making the performance of such systems slow. Here we discuss possible routes to address the later one: We introduce a GPU toolbox to make this powerful technique faster and more accessible to bio-medical researchers.

  13. A single laser all fibre based optical sensor and switching system and method for measuring velocity in atmospheric air flow

    DEFF Research Database (Denmark)

    2013-01-01

    A system for measuring a velocity of tracer particle motion in a fluid comprising at least one laser emitter configured to emit a continuous wave laser beam and a plur ality of optical devices being configured to alternately receive a laser beam, focusing the laser beam onto a same probe volume c...

  14. The 22nd International Conference on Optical Fibre Sensors, OFS-22

    Science.gov (United States)

    Liao, Yianbiao; Jin, Wei; Jones, Julian; Tatam, Ralph

    2013-09-01

    In October 2013, the 22nd International Conference on Optical Fibre Sensors was held in Beijing, attracting about 500 participants with 417 presentations. The conference began in 1983 in London, and in the subsequent 30 years has defined the subject. The conference is held approximately every 18 months, and rotates between three world regions: Asia/Pacific, Europe and the Americas. The conference is not 'owned' by any learned society or professional institution, but is organized by a self-sustaining international steering committee. This special feature represents the sixth occasion on which Measurement Science and Technology has published papers based on a development of a cross-section of work presented at the conference. The subject of optical fibre sensors has its beginnings in the enabling technologies of the optical fibre itself and the development of laser technologies suitable for practical use in demanding real-world applications. But the real driver for the subject in its early years was in the development of systems for defence applications, most notably for strategic-grade sea-bed hydrophone arrays for submarine detection, and the optical fibre gyroscope (the community has recently celebrated the 35th anniversary of its earliest publication) for aerospace navigation. Both applications continue to be important, but now with extensive civil applications: hydrophones for oil exploration and reservoir monitoring and management, and fibre gyroscopes for applications ranging from those requiring low cost and mass production (such as industrial robots and in agricultural machinery) to the most exotic and highest performance for space applications. The articles in this special feature exemplify the principal themes of the subject: enabling technologies, application-specific developments and systems considerations. In recent years, perhaps the most important—indeed, dominant—enabling technologies have been based on structuring of fibres: longitudinally, as

  15. Interaction of solitary pulses in single mode optical fibres | Usman ...

    African Journals Online (AJOL)

    Two solitary waves launched, by way of incidence, into an optical fibre from a single pulse if the pulses are in-phase as understood from results of inverse scattering transform method applied to the cubic nonlinear Schrödinger equations, (CNLSE\\'s). The single CNLSE is then understood to describe evolution of coupled ...

  16. Radioluminescent clad optical fibre X-ray sensor

    NARCIS (Netherlands)

    Fitzpatrick, C.; O'Donoghue, C.; Lewis, E.; Schöbel, J.; Bastaiens, B.; Bastiaens, Hubertus M.J.; van der Slot, Petrus J.M.

    2003-01-01

    An optical fibre X-ray sensor using cladding to core coupling of radioluminescent emissions from X-ray phosphors is presented. The sensor is tested using a line source normally used in the pre-ionisation of an excimer laser and is calibrated against a pendosimeter and the emission intensity of a

  17. Multi-Functional Fibre-Optic Microwave Links

    DEFF Research Database (Denmark)

    Gliese, Ulrik Bo

    1998-01-01

    GHz RF carrier. The frequency converting link demonstrates up-conversion of a 100 Mbit/s PSK signal from a 2 GHz carrier to a 9 GHz carrier with penalty-free transmission over 25 km of optical fibre. Finally, the transparent signal recovering link transmits a standard FM video 7.6 GHz radio...

  18. Fatigue Damage Monitoring of a Composite Step Lap Joint Using Distributed Optical Fibre Sensors.

    Science.gov (United States)

    Wong, Leslie; Chowdhury, Nabil; Wang, John; Chiu, Wing Kong; Kodikara, Jayantha

    2016-05-14

    Over the past few decades, there has been a considerable interest in the use of distributed optical fibre sensors (DOFS) for structural health monitoring of composite structures. In aerospace-related work, health monitoring of the adhesive joints of composites has become more significant, as they can suffer from cracking and delamination, which can have a significant impact on the integrity of the joint. In this paper, a swept-wavelength interferometry (SWI) based DOFS technique is used to monitor the fatigue in a flush step lap joint composite structure. The presented results will show the potential application of distributed optical fibre sensor for damage detection, as well as monitoring the fatigue crack growth along the bondline of a step lap joint composite structure. The results confirmed that a distributed optical fibre sensor is able to enhance the detection of localised damage in a structure.

  19. Propagation of Single-Mode Fibre Laser Beams through an Optical ABCD System with Circular Aperture at the Fibre Output End

    International Nuclear Information System (INIS)

    Kai-Liang, Duan; Jian-Feng, Li; Wei, Zhao; Yi-Shan, Wang

    2008-01-01

    Based on the expansion expression of the fundamental mode of a single-mode fibre in terms of Laguerre–Gauss modes, the propagation of a beam of a weakly guiding fibre laser through an optical ABCD system with a circular aperture at the fibre end is studied. The results show that there is much difference between the propagation of the laser beam described by the expansion expression and by the Gaussian mode approximation. The depth of focus of the laser beam is longer than that of the Gaussian modes

  20. Design of an optical fibre based angular position sensor for wire scanners complying with ultra-high vacuum, high temperature and radiation conditions of the CERN´s accelerators

    CERN Document Server

    Sirvent Blasco, Jose Luis; Azorin Poveda, Jose Maria

    The main objective of this thesis is to design and implement the relative optical position sensor based on optical fibre, related to the new design of wire scanner, also taking into account the general specifications of the whole design of the Vacuum Wire Scanner (VWS from here in advanced). According to the limitations of the environment this sensor must work under very hard conditions and provide as much accuracy as possible, this means that all the components must be carefully selected and also rated to high temperature, ultra high vacuum and radiation environment to provide the longest life time as possible.

  1. Control of the wavelength dependent thermo-optic coefficients in structured fibres

    DEFF Research Database (Denmark)

    Sørensen, Henrik Rokkjær; Canning, J.; Lægsgaard, Jesper

    2006-01-01

    By controlling the fibre geometry, the fraction of optical field within the holes and the inserted material of a photonic crystal fibre, we demonstrate that it is possible to engineer any arbitrary wavelength-dependent thermo-optic coefficient. The possibility of making a fibre with a zero temper...... temperature dependent thermo-optic coefficient, ideal for packaging of structured fibre gratings, is proposed and explored....

  2. Pyridine Vapors Detection by an Optical Fibre Sensor

    Directory of Open Access Journals (Sweden)

    Alberto Fernandez-Gutiérrez

    2008-02-01

    Full Text Available An optical fibre sensor has been implemented towards pyridine vapors detection;to achieve this, a novel vapochromic material has been used, which, in solid state, suffers achange in colour from blue to pink-white in presence of pyridine vapours. This complex isadded to a solution of PVC (Poly Vinyl Chloride, TBP (Tributylphosphate andtetrahydrofuran (THF, forming a plasticized matrix; by dip coating technique, the sensingmaterial is fixed onto a cleaved ended optical fibre. The fabrication process was optimizedin terms of number of dips and dipping speed, evaluating the final devices by dynamicrange. Employing a reflection set up, the absorbance spectra and changes in the reflectedoptical power of the sensors were registered to determine their response. A linear relationbetween optical power versus vapor concentration was obtained, with a detection limit of 1ppm (v/v.

  3. A fibre optic fluorescence sensor to measure redox level in tissues

    Science.gov (United States)

    Zhang, Wen Qi; Morrison, Janna L.; Darby, Jack R. T.; Plush, Sally; Sorvina, Alexandra; Brooks, Doug; Monro, Tanya M.; Afshar Vahid, Shahraam

    2018-01-01

    We report the design of a fibre optic-based redox detection system for investigating differences in metabolic activities of tissues. Our system shows qualitative agreement with the results collected from a commercial two- photon microscope system. Thus, demonstrating the feasibility of building an ex vivo and in vivo redox detection system that is low cost and portable.

  4. Fibre optic sensor for the detection of adulterant traces in coconut oil

    Science.gov (United States)

    Sheeba, M.; Rajesh, M.; Vallabhan, C. P. G.; Nampoori, V. P. N.; Radhakrishnan, P.

    2005-11-01

    The design and development of a fibre optic evanescent wave refractometer for the detection of trace amounts of paraffin oil and palm oil in coconut oil is presented. This sensor is based on a side-polished plastic optical fibre. At the sensing region, the cladding and a small portion of the core are removed and the fibre nicely polished. The sensing region is fabricated in such a manner that it sits perfectly within a bent mould. This bending of the sensing region enhances its sensitivity. The oil mixture of different mix ratios is introduced into the sensing region and we observed a sharp decrease in the output intensity. The observed variation in the intensity is found to be linear and the detection limit is 2% (by volume) paraffin oil/palm oil in coconut oil. The resolution of this refractometric sensor is of the order of 10-3. Since coconut oil is consumed in large volumes as edible oil in south India, this fibre optic sensor finds great relevance for the detection of adulterants such as paraffin oil or palm oil which are readily miscible in coconut oil. The advantage of this type of sensor is that it is inexpensive and easy to set up. Another attraction of the side-polished fibre is that only a very small amount of analyte is needed and its response time is only 7 s.

  5. Relationship between age and peripapillary retinal nerve fibre layer thickness: an optical coherence tomography study.

    Science.gov (United States)

    Wong, I Y H; Wong, A C M; Chan, C W N

    2010-08-01

    To evaluate the relationship between age and peripapillary retinal nerve fibre layer thickness in healthy Chinese subjects. Cross-sectional study. Regional hospital, Hong Kong. Healthy volunteers (n=218) of Chinese ethnicity with spherical equivalent of -6 to +4 dioptres were recruited for study from October 2001 to March 2003. Ocular examination was carried out and measurements of peripapillary retinal nerve fibre layer thickness were performed using optical coherence tomography (Carl Zeiss Humphrey OCT 2 machine), in a circular pattern of 3.4 mm diameter, centred on the optic disc. Mean retinal nerve fibre layer thickness and age. The mean age was 40 (standard deviation, 17; range, 11-69) years. The mean peripapillary retinal nerve fibre layer thickness was 111.6 (standard deviation, 18.5; range, 52.0-155.0) micrometres. Age correlated significantly with peripapillary retinal nerve fibre layer thickness (r= -0.28, Pfibre layer thickness (based on optical coherence tomography) correlates negatively with age, which can interfere with the assessment and monitoring of glaucoma patients. An age-adjusted normogram may be necessary to interpret results.

  6. Optofluidic realization and retaining of cell-cell contact using an abrupt tapered optical fibre.

    Science.gov (United States)

    Xin, Hongbao; Zhang, Yao; Lei, Hongxiang; Li, Yayi; Zhang, Huixian; Li, Baojun

    2013-01-01

    Studies reveal that there exists much interaction and communication between bacterial cells, with parts of these social behaviors depending on cell-cell contacts. The cell-cell contact has proved to be crucial for determining various biochemical processes. However, for cell culture with relatively low cell concentration, it is difficult to precisely control and retain the contact of a small group of cells. Particularly, the retaining of cell-cell contact is difficult when flows occur in the medium. Here, we report an optofluidic method for realization and retaining of Escherichia coli cell-cell contact in a microfluidic channel using an abrupt tapered optical fibre. The contact process is based on launching a 980-nm wavelength laser into the fibre, E. coli cells were trapped onto the fibre tip one after another, retaining cell-cell contact and forming a highly organized cell chain. The formed chains further show the ability as bio-optical waveguides.

  7. Fibre-top atomic force microscope probe with optical near-field detection capabilities.

    Science.gov (United States)

    Tiribilli, B; Margheri, G; Baschieri, P; Menozzi, C; Chavan, D; Iannuzzi, D

    2011-04-01

    We present a fibre-top probe fabricated by carving a tipped cantilever on an optical fibre, with the tip machined in correspondence of the fibre core. When approached to an optical prism illuminated under total internal reflection conditions, the tip of the cantilever detects the optical tunnelling signal, while the light coupled from the opposite end of the fibre measures the deflection of the cantilever. Our results suggest that fibre-top technology can be used for the development of a new generation of hybrid probes that can combine atomic force microscopy with scanning near field optical microscopy. © 2010 The Authors Journal of Microscopy © 2010 Royal Microscopical Society.

  8. Implications of information theory in optical fibre communications.

    Science.gov (United States)

    Agrell, Erik; Alvarado, Alex; Kschischang, Frank R

    2016-03-06

    Recent decades have witnessed steady improvements in our ability to harness the information-carrying capability of optical fibres. Will this process continue, or will progress eventually stall? Information theory predicts that all channels have a limited capacity depending on the available transmission resources, and thus it is inevitable that the pace of improvements will slow. However, information theory also provides insights into how transmission resources should, in principle, best be exploited, and thus may serve as a guide for where to look for better ways to squeeze more out of a precious resource. This tutorial paper reviews the basic concepts of information theory and their application in fibre-optic communications. © 2016 The Author(s).

  9. Interrogation of fibre Bragg gratings through a fibre optic rotary joint on a geotechnical centrifuge

    Science.gov (United States)

    Correia, Ricardo; James, Stephen W.; Marshall, Alec; Heron, Charles; Korposh, Sergiy

    2016-05-01

    The monitoring of an array of fibre Bragg gratings (FBGs) strain sensors was performed through a single channel, single mode fibre optic rotary joint (FORJ) mounted on a geotechnical centrifuge. The array of three FBGs was attached to an aluminum plate that was anchored at the ends and placed on the model platform of the centrifuge. Acceleration forces of up to 50g were applied and the reflection signal of the monitored FBGs recorded dynamically using a 2.5kHz FBG interrogator placed outside the centrifuge. The use of a FORJ allowed the monitoring of the FBGs without submitting the FBG interrogator to the high g-forces experienced in the centrifuge.

  10. Principles of optical fibre communication techniques: Noncoherent and coherent

    International Nuclear Information System (INIS)

    Jain, V.K.

    1990-01-01

    In this paper a brief historical description of optical fibre communication system (OFCS) has been presented and the main characteristics of the basic components used in it are summarized. Introduction of noncoherent and coherent (homodyne and heterodyne) system is given. In coherent OFCS, source linewidth requirement, phase and polarization - diversity and combined phase and polarization - diversity receivers are described. (author). 16 refs, 8 figs, 1 tab

  11. Optical Fibre Biosensors Using Enzymatic Transducers to Monitor Glucose

    Czech Academy of Sciences Publication Activity Database

    Scully, P. J.; Betancor, L.; Bolyó, Juraj; Dzyadevych, S.; Guisan, J.M.; Fernández-Lafuente, R.; Jaffrezic-Renault, N.; Kuncová, Gabriela; Matějec, Vlastimil; O´Kennedy, B.; Podrazký, Ondřej; Rose, K.

    2007-01-01

    Roč. 18, č. 10 (2007), s. 3177-3186 ISSN 0957-0233 Grant - others:MATINOES(XE) GRD1/2001/40477 Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z20670512 Source of funding: R - rámcový projekt EK Keywords : optical fibre biosensor * quenching Subject RIV: CE - Biochemistry Impact factor: 1.297, year: 2007

  12. Isolan - A Fibre Optic Network Conforming To IEEE 802.3 Standards

    Science.gov (United States)

    Roworth, D. A. A.; Howe, N.

    1986-10-01

    The progress of the IEEE 802.3 standard for fibre optic LANs is indicated with reference to both mixed media networks and full fibre networks. For a fibre optic network the most suitable layout is a "snowflake" topology composed of multiport repeaters and active fibre hubs. A range of components is described which enables the realisation of such a topology in conformance with the IEEE 802.3 standard.

  13. Precision 3-D microscopy with intensity modulated fibre optic scanners

    Science.gov (United States)

    Olmos, P.

    2016-01-01

    Optical 3-D imagers constitute a family of precision and useful instruments, easily available on the market in a wide variety of configurations and performances. However, besides their cost they usually provide an image of the object (i.e. a more or less faithful representation of the reality) instead of a truly object's reconstruction. Depending on the detailed working principles of the equipment, this reconstruction may become a challenging task. Here a very simple yet reliable device is described; it is able to form images of opaque objects by illuminating them with an optical fibre and collecting the reflected light with another fibre. Its 3-D capability comes from the spatial filtering imposed by the fibres together with their movement (scanning) along the three directions: transversal (surface) and vertical. This unsophisticated approach allows one to model accurately the entire optical process and to perform the desired reconstruction, finding that information about the surface which is of interest: its profile and its reflectance, ultimately related to the type of material.

  14. Characterisation of Flax Fibres and Flax Fibre Composites. Being cellulose based sources of materials

    DEFF Research Database (Denmark)

    Aslan, Mustafa

    a transition value, as predicted by the volumetric composition model. This leads furthermore to a scatter in the experimental data of stiffness at high fibre weight fractions. The qualitative analysis of the composite cross sections by microscopy also shows that the low and high pressure composites have......Cellulosic fibres, like wood and plant fibres, have the potential for use as load-bearing constituents in composite materials due to their attractive properties such as high stiffness-to-weight ratio that makes cellulosic fibre composites ideal for many structural applications. There is thus...... a growing interest among composite manufacturers for such low-cost and low-weight cellulosic fibre composites. In addition, wood and plant fibre based composites with thermoplastic polymeric matrices are recyclable, and they are cost attractive alternatives to oil based fibre reinforced polymer composites...

  15. A review of recent advances in optical fibre sensors for in vivo dosimetry during radiotherapy.

    Science.gov (United States)

    O'Keeffe, S; McCarthy, D; Woulfe, P; Grattan, M W D; Hounsell, A R; Sporea, D; Mihai, L; Vata, I; Leen, G; Lewis, E

    2015-06-01

    This article presents an overview of the recent developments and requirements in radiotherapy dosimetry, with particular emphasis on the development of optical fibre dosemeters for radiotherapy applications, focusing particularly on in vivo applications. Optical fibres offer considerable advantages over conventional techniques for radiotherapy dosimetry, owing to their small size, immunity to electromagnetic interferences, and suitability for remote monitoring and multiplexing. The small dimensions of optical fibre-based dosemeters, together with being lightweight and flexible, mean that they are minimally invasive and thus particularly suited to in vivo dosimetry. This means that the sensor can be placed directly inside a patient, for example, for brachytherapy treatments, the optical fibres could be placed in the tumour itself or into nearby critical tissues requiring monitoring, via the same applicators or needles used for the treatment delivery thereby providing real-time dosimetric information. The article outlines the principal sensor design systems along with some of the main strengths and weaknesses associated with the development of these techniques. The successful demonstration of these sensors in a range of different clinical environments is also presented.

  16. A fibre-optic oxygen sensor for monitoring human breathing

    International Nuclear Information System (INIS)

    Chen, Rongsheng; Formenti, Federico; Hahn, Clive E W; Farmery, Andrew D; Obeid, Andy

    2013-01-01

    The development and construction of a tapered-tip fibre-optic fluorescence based oxygen sensor is described. The sensor is suitable for fast and real-time monitoring of human breathing. The sensitivity and response time of the oxygen sensor were evaluated in vitro with a gas pressure chamber system, where oxygen partial pressure was rapidly changed between 5 and 15 kPa, and then in vivo in five healthy adult participants who synchronized their breathing to a metronome set at 10, 20, 30, 40, 50, and 60 breaths min –1 . A Datex Ultima medical gas analyser was used to monitor breathing rate as a comparator. The sensor's response time in vitro was less than 150 ms, which allows accurate continuous measurement of inspired and expired oxygen pressure. Measurements of breathing rate by means of our oxygen sensor and of the Datex Ultima were in strong agreement. The results demonstrate that the device can reliably resolve breathing rates up to 60 breaths min –1 , and that it is a suitable cost-effective alternative for monitoring breathing rates and end-tidal oxygen partial pressure in the clinical setting. The rapid response time of the sensor may allow its use for monitoring rapid breathing rates as occur in children and the newborn. (note)

  17. Connectorization of fibre Bragg grating sensors recorded in microstructured polymer optical fibre

    DEFF Research Database (Denmark)

    Abang, A.; Saez-Rodriguez, D.; Nielsen, Kristian

    2013-01-01

    We describe te production and characterization of FC/PC connectorised fibre Bragg grating sensors in polymer fibre. Sensors were recorded in few-moded and single mode microstructured fibre composed of poly (methyl methacrylate).......We describe te production and characterization of FC/PC connectorised fibre Bragg grating sensors in polymer fibre. Sensors were recorded in few-moded and single mode microstructured fibre composed of poly (methyl methacrylate)....

  18. Spectral and kinetic analysis of radiation induced optical attenuation in silica: towards intrinsic fibre optic dosimetry?

    International Nuclear Information System (INIS)

    Borgermans, P.

    2002-01-01

    The document is an abstract of a PhD thesis. The PhD work concerns the detailed investigation of the behaviour of optical fibres in radiation fields such as is the case for various nuclear and space application,s. The core of the work concerns the spectral and kinetic analysis of the radiation induced optical attenuation. Models describing underlying physical phenomena, both for the spectral and the time dimensions, have been developed. The potential of silica optical fibre waveguides for intrinsic dosimetry has been assessed by employing specific properties of radiation induced defects in the silica waveguide material

  19. Electromagnetic waves in optical fibres in a magnetic field

    International Nuclear Information System (INIS)

    Gorelik, V S; Burdanova, M G

    2016-01-01

    A new method is reported of recording the secondary radiation of luminescent substances based on the use of capillary fibres of great length. Theoretical analysis of the dispersion curves of electromagnetic radiation in capillary fibres doped with erbium ions Er 3+ has been established. The Lorentz model is used for describing the dispersion properties of electromagnetic waves in a homogeneous medium doped with rare-earth ions. The dispersion dependencies of polariton and axion–polariton waves in erbium nitrate hydrate are determined on the basis of the model of the interaction between electromagnetic waves and the resonance electronic states of erbium ions in the absence and presence of a magnetic field. (paper)

  20. Optical loss estimation of the irradiated fibres by measuring their own luminescence

    International Nuclear Information System (INIS)

    Abdurakhmanov, B.S.; Gasanov, E.M.

    2006-01-01

    Full text: The new practical applications of the optical fibres suppose their continuous operation under the influence of various external factors. When the fibres are used as of shower detectors [1], formed in collisions of charged particles in the vast relativistic energies, such factors, in the first instance, are the following: γ-radiation, neutron fluences, X-ray radiation and others. Upon the influence of these fluences the physical properties of fibres, the main of which are luminescent properties and optical losses, are changed. To take into account the effective signal distortion, which is formed by mentioned changes of fibre properties the effective methods of measuring optical losses is necessary. In present work, the method to measure optical losses is suggested, by using fibre's own X-ray luminescence as a probing light. The essence of the method consists of the following. In some point (about 1,5-2 Cm) of long fibre X-ray radiation excites the luminescence. The part of luminescence light transported by fibre spreads along fibre and is detected at the end of fibre. By scanning luminescence excitation area the dependence of the passed light intensity from the length of fibre is measured. Obtained dependence allows calculation of the quantity of the optical losses in investigated fibre. The obtained measurement results were discussed. The existing methods for measuring of optical losses [2, 3], are analyzed and the advantages and disadvantages of the offered method are presented. (author)

  1. Step-index optical fibre drawn from 3D printed preforms

    OpenAIRE

    CooK, Kevin; Balle, Geoffrey; Canning, John; Chartier, Loic; Athanaze, Tristan; Hossain, Md Arafat; Han, Chunyang; Comatti, Jade-Edouard; Luo, Yanhua; Peng, Gang-Ding

    2016-01-01

    Optical fibre is drawn from a dual-head 3D printer fabricated preform made of two optically transparent plastics with a high index core (NA ~ 0.25, V > 60). The asymmetry observed in the fibre arises from asymmetry in the 3D printing process. The highly multi-mode optical fibre has losses measured by cut-back as low as {\\alpha} ~ 0.44 dB/cm in the near IR.

  2. Fibre optic ocean bottom seismic cable system: from innovation to commercial success

    Science.gov (United States)

    Kringlebotn, Jon Thomas; Nakstad, Hilde; Eriksrud, Morten

    2009-10-01

    Optoplan has been awarded the world's first commercial contract for a fibre optic Ocean Bottom Seismic Cable (OBC) system [1] for permanent reservoir monitoring at the Ekofisk field in the North Sea. An area of 60 sq. km of the seabed will be covered by four component (4C) sensors in 2010. The system consists of i) a top-side (platform) laser interrogation and recording system, and ii) a wet-end system including 200 km of seismic cable with 4000 sensor stations, each containing 4 FBG-based interferometric sensors (three accelerometers and one hydrophone). The wet-end system includes 24000 FBGs and more than 3500km of optical fibres, and will probably be the largest single fibre optic sensor network ever made. The completely passive wet-end part of the system is designed to operate with ultra-high reliability subsea over more than 25 years. The system is expected to significantly enhance the oil and gas recovery of the field. This commercial success is a result of i) Optoplan's long experience and credibility in the field of fibreoptic sensors for the oil and gas industry [2], [3], ii) close collaboration with oil companies and qualification through extensive field testing [4], [5], iii) the establishment of a high capacity supply chain and manufacturing system with innovative automated processes, iv) sensor/manufacturing design for high reliability and good manufacturability with high yield, v) innovative sensor fibre network and instrumentation design [1], [6], [7], [

  3. Investigation of bending loss in a single-mode optical fibre

    Indian Academy of Sciences (India)

    Abstract. Loss of optical power in a single-mode optical fibre due to bending has been investigated for a wavelength of 1550 nm. In this experiment, the effects of bending radius (4–15 mm, with steps of 1 mm), and wrapping turns (up to 40 turns) on loss have been studied. Twisting the optical fibre and its influence on power ...

  4. Distributed strain measurement in perfluorinated polymer optical fibres using optical frequency domain reflectometry

    International Nuclear Information System (INIS)

    Liehr, Sascha; Wendt, Mario; Krebber, Katerina

    2010-01-01

    We present the latest advances in distributed strain measurement in perfluorinated polymer optical fibres (POFs) using backscatter techniques. Compared to previously introduced poly(methyl methacrylate) POFs, the measurement length can be extended to more than 500 m at improved spatial resolution of a few centimetres. It is shown that strain in a perfluorinated POF can be measured up to 100%. In parallel to these investigations, the incoherent optical frequency domain reflectometry (OFDR) technique is introduced to detect strained fibre sections and to measure distributed length change along the fibre with sub-millimetre resolution by applying a cross-correlation algorithm to the backscatter signal. The overall superior performance of the OFDR technique compared to the optical time domain reflectometry in terms of accuracy, dynamic range, spatial resolution and measurement speed is presented. The proposed sensor system is a promising technique for use in structural health monitoring applications where the precise detection of high strain is required

  5. Evolution of optical fibre cabling components at CERN: Performance and technology trends analysis

    Science.gov (United States)

    Shoaie, Mohammad Amin; Meroli, Stefano; Machado, Simao; Ricci, Daniel

    2018-05-01

    CERN optical fibre infrastructure has been growing constantly over the past decade due to ever increasing connectivity demands. The provisioning plan and fibre installation of this vast laboratory is performed by Fibre Optics and Cabling Section at Engineering Department. In this paper we analyze the procurement data for essential fibre cabling components during a five-year interval to extract the existing trends and anticipate future directions. The analysis predicts high contribution of LC connector and an increasing usage of multi-fibre connectors. It is foreseen that single-mode fibres become the main fibre type for mid and long-range installations while air blowing would be the major installation technique. Performance assessment of various connectors shows that the expanded beam ferrule is favored for emerging on-board optical interconnections thanks to its scalable density and stable return-loss.

  6. A Novel Approach to the Sensing of Liquid Density Using a Plastic Optical Fibre Cantilever Beam

    Science.gov (United States)

    Kulkarni, Atul; Kim, Youngjin; Kim, Taesung

    2009-01-01

    This article reports for the first time the use of a plastic optical fibre (POF) cantilever beam to measure the density of a liquid. The sensor is based on the Archimedes buoyancy principle. The sensor consists of a POF bonded on the surface of a metal beam in the form of a cantilever configuration, and at the free end of the beam a displacer is…

  7. Photo- and thermal degradation of olive oil measured using an optical fibre smartphone spectrofluorimeter

    Science.gov (United States)

    Hossain, Md Arafat; Canning, John; Cook, Kevin; Ast, Sandra; Jamalipour, Abbas

    2017-04-01

    Degradation of olive oil under light and heat are analysed using an optical fibre based low-cost portable smartphone spectrofluorimeter. Visible fluorescence bands associated with phenolic acids, vitamins and chlorophyll centred at λ 452, 525 and 670 nm respectively are generated using near-UV excitation (LED λex 370 nm), of extra virgin olive oil are degraded more likely than refined olive oil under light and heat exposure. Packaging is shown to be critical when assessing the origin of degradation.

  8. Non-interferometric determination of optical anisotropy in highly-oriented fibres using transport intensity equation technique

    Science.gov (United States)

    Sokkar, T. Z. N.; El-Farahaty, K. A.; El-Bakary, M. A.; Raslan, M. I.; Omar, E. Z.; Hamza, A. A.

    2018-03-01

    The optical setup of the transport intensity equation (TIE) technique is developed to be valid for measuring the optical properties of the highly-oriented anisotropic fibres. This development is based on the microstructure models of the highly-oriented anisotropic fibres and the principle of anisotropy. We provide the setup of TIE technique with polarizer which is controlled via stepper motor. This developed technique is used to investigate the refractive indices in the parallel and perpendicular polarization directions of light for the highly-oriented poly (ethylene terephthalate) (PET) fibres and hence its birefringence. The obtained results through the developed TIE technique for PET fibre are compared with that determined experimentally using the Mach-Zehnder interferometer under the same conditions. The comparison shows a good agreement between the obtained results from the developed technique and that obtained from the Mach-Zehnder interferometer technique.

  9. Some fundamental problems relating to optical fibres. II. The ultimate bandwidth performance of optical fibre transmission lines

    International Nuclear Information System (INIS)

    Gambling, W.A.

    1977-01-01

    Optical fibre transmission lines can be divided broadly into two types, namely single mode and multimode. The bandwidth of the former is limited by the variation in group velocity with frequency caused by mode dispersion and material dispersion, with predicted values of tens of gigahertz over tens of kilometres for a monochromatic carrier, falling to approximately l GHz over 1km for a typical injection laser. Multimode fibres have the additional limitation of group delay between the various propagating modes. Several schemes have been suggested for reducing this effect, such as: (a) exciting only a few modes (ideally one) in a fibre exhibiting no mode conversion, (b) inducing coupling between bound modes but not into radiating modes, and (c) equalizing the mode velocities by means of a suitable refractive index profile. Most effort is presently being devoted to (c) and it has been shown that the optimum profile is affected by leaky modes and material dispersion. By operating at a wavelength in the region of 1.25μm the effect of material dispersion can be greatly reduced and bandwidths in excess of 1 GHz over 1km might be expected, even with sources of large linewidth. (author)

  10. The Symmetry of Optical Field in Photonic Crystal Fibre with Trigonal Symmetry

    Directory of Open Access Journals (Sweden)

    Ivan Turek

    2006-01-01

    Full Text Available Some photographs of intensity of optical field of a photonic crystal fibre are presented in the contribution. Presented photographs document that the symmetry of photonic crystal creating the cladding of fibre is manifested in the symmetry of distribution of the optical field intensity. In case when more modes are excited in the fibre the symmetry of the generated field can be different as the symmetry of the eventual modes. How the symmetry may be changed is illustrated by amodel example.

  11. OPTICAL FIBRE WITH HIGH NUMERICAL APERTURE, METHOD OF ITS PRODUCTION, AND USE THEREOF

    DEFF Research Database (Denmark)

    2003-01-01

    An article comprising an optical fibre, the fibre comprising at least one core surrounded by a first outer cladding region, the first outer cladding region being surrounded by a second outer cladding region, the first outer cladding region in the cross-section comprising a number of first outer...... an optical wavelength of light guided through the fibre when in use; a method of its production, and use thereof...

  12. Ultrasensitive plasmonic sensing in air using optical fibre spectral combs.

    Science.gov (United States)

    Caucheteur, Christophe; Guo, Tuan; Liu, Fu; Guan, Bai-Ou; Albert, Jacques

    2016-11-11

    Surface plasmon polaritons (SPP) can be excited on metal-coated optical fibres, enabling the accurate monitoring of refractive index changes. Configurations reported so far mainly operate in liquids but not in air because of a mismatch between permittivities of guided light modes and the surrounding medium. Here we demonstrate a plasmonic optical fibre platform that overcomes this limitation. The underpinning of our work is a grating architecture-a gold-coated highly tilted Bragg grating-that excites a spectral comb of narrowband-cladding modes with effective indices near 1.0 and below. Using conventional spectral interrogation, we measure shifts of the SPP-matched resonances in response to static atmospheric pressure changes. A dynamic experiment conducted using a laser lined-up with an SPP-matched resonance demonstrates the ability to detect an acoustic wave with a resolution of 10 -8 refractive index unit (RIU). We believe that this configuration opens research directions for highly sensitive plasmonic sensing in gas.

  13. Observation of Kuznetsov-Ma soliton dynamics in optical fibre

    Science.gov (United States)

    Kibler, B.; Fatome, J.; Finot, C.; Millot, G.; Genty, G.; Wetzel, B.; Akhmediev, N.; Dias, F.; Dudley, J. M.

    2012-01-01

    The nonlinear Schrödinger equation (NLSE) is a central model of nonlinear science, applying to hydrodynamics, plasma physics, molecular biology and optics. The NLSE admits only few elementary analytic solutions, but one in particular describing a localized soliton on a finite background is of intense current interest in the context of understanding the physics of extreme waves. However, although the first solution of this type was the Kuznetzov-Ma (KM) soliton derived in 1977, there have in fact been no quantitative experiments confirming its validity. We report here novel experiments in optical fibre that confirm the KM soliton theory, completing an important series of experiments that have now observed a complete family of soliton on background solutions to the NLSE. Our results also show that KM dynamics appear more universally than for the specific conditions originally considered, and can be interpreted as an analytic description of Fermi-Pasta-Ulam recurrence in NLSE propagation. PMID:22712052

  14. Comparative analysis of algorithms for compensation of nonlinear distortions in fibre-optic links

    Science.gov (United States)

    Burdin, V. A.; Bourdine, A. V.; Grigorov, I. V.

    2017-12-01

    We report the results of numerical modelling and comparative analysis of two algorithms for digital signal processing intended for signal demodulation in fibre-optic links (FOLs) operating in a nonlinear mode. The first algorithm is based on the use of nonlinear Schrödinger filters and the second one utilises the ‘reception in general with bit-by-bit decision making’ technique. It is found that the latter algorithm is more noiseproof, compared to the first one (with a SNR gain of about 0.5 dB), in single-channel fibre-optic links, and its operation does not require knowledge of the link parameters; therefore, the second algorithm can also be constructed for wavelength-division multiplexing systems.

  15. Study on the Sensing Coating of the Optical Fibre CO2 Sensor

    Science.gov (United States)

    Wysokiński, Karol; Napierała, Marek; Stańczyk, Tomasz; Lipiński, Stanisław; Nasiłowski, Tomasz

    2015-01-01

    Optical fibre carbon dioxide (CO2) sensors are reported in this article. The principle of operation of the sensors relies on the absorption of light transmitted through the fibre by a silica gel coating containing active dyes, including methyl red, thymol blue and phenol red. Stability of the sensor has been investigated for the first time for an absorption based CO2 optical fiber sensor. Influence of the silica gel coating thickness on the sensitivity and response time has also been studied. The impact of temperature and humidity on the sensor performance has been examined too. Response times of reported sensors are very short and reach 2–3 s, whereas the sensitivity of the sensor ranges from 3 to 10 for different coating thicknesses. Reported parameters make the sensor suitable for indoor and industrial use. PMID:26694412

  16. Study on the Sensing Coating of the Optical Fibre CO₂ Sensor.

    Science.gov (United States)

    Wysokiński, Karol; Napierała, Marek; Stańczyk, Tomasz; Lipiński, Stanisław; Nasiłowski, Tomasz

    2015-12-17

    Optical fibre carbon dioxide (CO₂) sensors are reported in this article. The principle of operation of the sensors relies on the absorption of light transmitted through the fibre by a silica gel coating containing active dyes, including methyl red, thymol blue and phenol red. Stability of the sensor has been investigated for the first time for an absorption based CO₂ optical fiber sensor. Influence of the silica gel coating thickness on the sensitivity and response time has also been studied. The impact of temperature and humidity on the sensor performance has been examined too. Response times of reported sensors are very short and reach 2-3 s, whereas the sensitivity of the sensor ranges from 3 to 10 for different coating thicknesses. Reported parameters make the sensor suitable for indoor and industrial use.

  17. Photoinduced Bragg grating formation in optical fibres as a consequence of convective instability

    International Nuclear Information System (INIS)

    Furman, A.S.

    1993-10-01

    The photoinduced formation of Bragg gratings in optical fibres is explained as a consequence of convective instability. Close analogy is emphasized between this phenomenon and the photoinduced second harmonic generation in optical fibres. The observed grating formation is interpreted as amplification of very low frequency noise. Predictions concerning the transient processes are made which could be checked experimentally. (author). 9 refs

  18. A simple optical fibre-linked remote control system for multiple devices

    Indian Academy of Sciences (India)

    The programming voltage required for the remote control of the power supply can be derived from a DAC, with a reference voltage of 10 V. The serial data from the COM-port is used to drive an optical fibre transmitter. An optical fibre carries the serial data from the transmitter to the receiver at the remote end. This serial data ...

  19. Fibre-optical techniques for measuring various properties of shock waves

    NARCIS (Netherlands)

    Prinse, W.C.; Esveld, R.J. van; Oostdam, R. van; Rooijen, M. van; Bouma, R.H.B.

    1999-01-01

    For the past years we have developed several optical techniques to measure properties of shock waves. The fibre optic probe (FOP) is developed to measure the shock-wave velocity and/or the detonation velocity inside an explosive. The space resolution can be as small as 0.5 mm. Single fibres are used

  20. Fibre Optic Gyroscope Developments Using Integrated Optic Components

    Science.gov (United States)

    Minford, W. J.; DePaula, R. M.

    1988-09-01

    The sensing of rotation using counterpropagating optical beams in a fiber loop (the SAGNAC effect) has gone through extensive developments and demonstrations since first proved feasible by Vali and Shorthilll in 1976. The interferometric fiber gyroscope minimum configuration2 which uses a common input-output port and single-mode filter was developed to provide the extreme high stability necessary to reach the sensitivities at low rotation rates attainable with current state-of-the-art detectors. The simplicity and performance of this configuration has led to its acceptance and wide-spread use. In order to increase the mechanical stability of this system, all single-mode fiber components are employed and a further advancement to integrated optics has enabled most of the optical functions to be placed on a single mass-producible substrate. Recent improvements in the components (eg polarization maintaining fiber and low coherence sources) have further enhanced the performance of the minimum configuration gyro. This presentation focused on the impact of LiNbO3 integrated optic components on gyroscope developments. The use of Ti-indiffused LiNbO3 waveguide optical circuits in interferometric fiber optic gyroscopes has taken two directions: to utilize only the phase modulator, or to combine many of the minimum configuration optical functions on the electro-optic substrate. The high-bandwidth phase modulator is the driving force for using LiNbO3 waveguide devices. This device allows both biasing the gyro for maximum sensitivity and closing the loop via frequency shifting, for example, thus increasing the dynamic range of the gyro and the linearity of the scale factor. Efforts to implement most of the minimum configuration optical functions onto a single LiNbO3 substrate have been led by Thomson CSF.3 They have demonstrated an interferometric gyroscope with excellent performance using a LiNbO3 optical circuit containing a Y-splitter, phase modulator, and surface

  1. Real time monitoring of water level and temperature in storage fuel pools through optical fibre sensors.

    Science.gov (United States)

    Rizzolo, S; Périsse, J; Boukenter, A; Ouerdane, Y; Marin, E; Macé, J-R; Cannas, M; Girard, S

    2017-08-18

    We present an innovative architecture of a Rayleigh-based optical fibre sensor for the monitoring of water level and temperature inside storage nuclear fuel pools. This sensor, able to withstand the harsh constraints encountered under accidental conditions such as those pointed-out during the Fukushima-Daiichi event (temperature up to 100 °C and radiation dose level up to ~20 kGy), exploits the Optical Frequency Domain Reflectometry technique to remotely monitor a radiation resistant silica-based optical fibre i.e. its sensing probe. We validate the efficiency and the robustness of water level measurements, which are extrapolated from the temperature profile along the fibre length, in a dedicated test bench allowing the simulation of the environmental operating and accidental conditions. The conceived prototype ensures an easy, practical and no invasive integration into existing nuclear facilities. The obtained results represent a significant breakthrough and comfort the ability of the developed system to overcome both operating and accidental constraints providing the distributed profiles of the water level (0-to-5 m) and temperature (20-to-100 °C) with a resolution that in accidental condition is better than 3 cm and of ~0.5 °C respectively. These new sensors will be able, as safeguards, to contribute and reinforce the safety in existing and future nuclear power plants.

  2. Image transport through a disordered optical fibre mediated by transverse Anderson localization.

    Science.gov (United States)

    Karbasi, Salman; Frazier, Ryan J; Koch, Karl W; Hawkins, Thomas; Ballato, John; Mafi, Arash

    2014-02-25

    Transverse Anderson localization of light allows localized optical-beam-transport through a transversely disordered and longitudinally invariant medium. Its successful implementation in disordered optical fibres recently resulted in the propagation of localized beams of radii comparable to that of conventional optical fibres. Here we demonstrate optical image transport using transverse Anderson localization of light. The image transport quality obtained in the polymer disordered optical fibre is comparable to or better than some of the best commercially available multicore image fibres with less pixelation and higher contrast. It is argued that considerable improvement in image transport quality can be obtained in a disordered fibre made from a glass matrix with near wavelength-size randomly distributed air-holes with an air-hole fill-fraction of 50%. Our results open the way to device-level implementation of the transverse Anderson localization of light with potential applications in biological and medical imaging.

  3. Image transport through a disordered optical fibre mediated by transverse Anderson localization

    Science.gov (United States)

    Karbasi, Salman; Frazier, Ryan J.; Koch, Karl W.; Hawkins, Thomas; Ballato, John; Mafi, Arash

    2014-02-01

    Transverse Anderson localization of light allows localized optical-beam-transport through a transversely disordered and longitudinally invariant medium. Its successful implementation in disordered optical fibres recently resulted in the propagation of localized beams of radii comparable to that of conventional optical fibres. Here we demonstrate optical image transport using transverse Anderson localization of light. The image transport quality obtained in the polymer disordered optical fibre is comparable to or better than some of the best commercially available multicore image fibres with less pixelation and higher contrast. It is argued that considerable improvement in image transport quality can be obtained in a disordered fibre made from a glass matrix with near wavelength-size randomly distributed air-holes with an air-hole fill-fraction of 50%. Our results open the way to device-level implementation of the transverse Anderson localization of light with potential applications in biological and medical imaging.

  4. Electron irradiation response on Ge and Al-doped SiO{sub 2} optical fibres

    Energy Technology Data Exchange (ETDEWEB)

    Yaakob, N.H.; Wagiran, H. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim (Malaysia); Hossain, I., E-mail: imamhossain@utm.m [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim (Malaysia); Ramli, A.T. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim (Malaysia); Bradley, D.A [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Hashim, S. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim (Malaysia); Ali, H. [Department of Radiotherapy and Oncology, Hospital Sultan Ismail, Johor Darul Takzim (Malaysia)

    2011-05-01

    This paper describes the thermoluminescence response, sensitivity, stability and reproducibility of SiO{sub 2} optical fibres with various electron energies and doses. The TL materials that comprise Al- and Ge-doped silica fibres were used in this experiment. The TL results are compared with those of the commercially available TLD-100. The doped SiO{sub 2} optical fibres and TLD-100 are placed in a solid phantom and irradiated with 6, 9 and 12 MeV electron beams at doses ranging from 0.2 to 4.0 Gy using the LINAC at Hospital Sultan Ismail, Johor Bahru, Malaysia. It was found that the commercially available Al- and Ge-doped optical fibres have a linear dose-TL signal relationship. The intensity of TL response of Ge-doped fibre is markedly greater than that of the Al-doped fibre.

  5. Electron irradiation response on Ge and Al-doped SiO 2 optical fibres

    Science.gov (United States)

    Yaakob, N. H.; Wagiran, H.; Hossain, I.; Ramli, A. T.; Bradley, D. A.; Hashim, S.; Ali, H.

    2011-05-01

    This paper describes the thermoluminescence response, sensitivity, stability and reproducibility of SiO 2 optical fibres with various electron energies and doses. The TL materials that comprise Al- and Ge-doped silica fibres were used in this experiment. The TL results are compared with those of the commercially available TLD-100. The doped SiO 2 optical fibres and TLD-100 are placed in a solid phantom and irradiated with 6, 9 and 12 MeV electron beams at doses ranging from 0.2 to 4.0 Gy using the LINAC at Hospital Sultan Ismail, Johor Bahru, Malaysia. It was found that the commercially available Al- and Ge-doped optical fibres have a linear dose-TL signal relationship. The intensity of TL response of Ge-doped fibre is markedly greater than that of the Al-doped fibre.

  6. Electron irradiation response on Ge and Al-doped SiO2 optical fibres

    International Nuclear Information System (INIS)

    Yaakob, N.H.; Wagiran, H.; Hossain, I.; Ramli, A.T.; Bradley, D.A; Hashim, S.; Ali, H.

    2011-01-01

    This paper describes the thermoluminescence response, sensitivity, stability and reproducibility of SiO 2 optical fibres with various electron energies and doses. The TL materials that comprise Al- and Ge-doped silica fibres were used in this experiment. The TL results are compared with those of the commercially available TLD-100. The doped SiO 2 optical fibres and TLD-100 are placed in a solid phantom and irradiated with 6, 9 and 12 MeV electron beams at doses ranging from 0.2 to 4.0 Gy using the LINAC at Hospital Sultan Ismail, Johor Bahru, Malaysia. It was found that the commercially available Al- and Ge-doped optical fibres have a linear dose-TL signal relationship. The intensity of TL response of Ge-doped fibre is markedly greater than that of the Al-doped fibre.

  7. An Optical Fibre Depth (Pressure Sensor for Remote Operated Vehicles in Underwater Applications

    Directory of Open Access Journals (Sweden)

    Dinesh Babu Duraibabu

    2017-02-01

    Full Text Available A miniature sensor for accurate measurement of pressure (depth with temperature compensation in the ocean environment is described. The sensor is based on an optical fibre Extrinsic Fabry-Perot interferometer (EFPI combined with a Fibre Bragg Grating (FBG. The EFPI provides pressure measurements while the Fibre Bragg Grating (FBG provides temperature measurements. The sensor is mechanically robust, corrosion-resistant and suitable for use in underwater applications. The combined pressure and temperature sensor system was mounted on-board a mini remotely operated underwater vehicle (ROV in order to monitor the pressure changes at various depths. The reflected optical spectrum from the sensor was monitored online and a pressure or temperature change caused a corresponding observable shift in the received optical spectrum. The sensor exhibited excellent stability when measured over a 2 h period underwater and its performance is compared with a commercially available reference sensor also mounted on the ROV. The measurements illustrates that the EFPI/FBG sensor is more accurate for depth measurements (depth of ~0.020 m.

  8. An Optical Fibre Depth (Pressure) Sensor for Remote Operated Vehicles in Underwater Applications.

    Science.gov (United States)

    Duraibabu, Dinesh Babu; Poeggel, Sven; Omerdic, Edin; Capocci, Romano; Lewis, Elfed; Newe, Thomas; Leen, Gabriel; Toal, Daniel; Dooly, Gerard

    2017-02-19

    A miniature sensor for accurate measurement of pressure (depth) with temperature compensation in the ocean environment is described. The sensor is based on an optical fibre Extrinsic Fabry-Perot interferometer (EFPI) combined with a Fibre Bragg Grating (FBG). The EFPI provides pressure measurements while the Fibre Bragg Grating (FBG) provides temperature measurements. The sensor is mechanically robust, corrosion-resistant and suitable for use in underwater applications. The combined pressure and temperature sensor system was mounted on-board a mini remotely operated underwater vehicle (ROV) in order to monitor the pressure changes at various depths. The reflected optical spectrum from the sensor was monitored online and a pressure or temperature change caused a corresponding observable shift in the received optical spectrum. The sensor exhibited excellent stability when measured over a 2 h period underwater and its performance is compared with a commercially available reference sensor also mounted on the ROV. The measurements illustrates that the EFPI/FBG sensor is more accurate for depth measurements (depth of ~0.020 m).

  9. A new fibre optic pulse oximeter probe for monitoring splanchnic organ arterial blood oxygen saturation.

    Science.gov (United States)

    Hickey, M; Samuels, N; Randive, N; Langford, R; Kyriacou, P A

    2012-12-01

    A new, continuous method of monitoring splanchnic organ oxygen saturation (SpO(2)) would make the early detection of inadequate tissue oxygenation feasible, reducing the risk of hypoperfusion, severe ischaemia, and, ultimately, death. In an attempt to provide such a device, a new fibre optic based reflectance pulse oximeter probe and processing system were developed followed by an in vivo evaluation of the technology on seventeen patients undergoing elective laparotomy. Photoplethysmographic (PPG) signals of good quality and high signal-to-noise ratio were obtained from the small bowel, large bowel, liver and stomach. Simultaneous peripheral PPG signals from the finger were also obtained for comparison purposes. Analysis of the amplitudes of all acquired PPG signals indicated much larger amplitudes for those signals obtained from splanchnic organs than those obtained from the finger. Estimated SpO(2) values for splanchnic organs showed good agreement with those obtained from the finger fibre optic probe and those obtained from a commercial device. These preliminary results suggest that a miniaturized 'indwelling' fibre optic sensor may be a suitable method for pre-operative and post-operative evaluation of splanchnic organ SpO(2) and their health. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  10. Limitations in distance and frequency due to chromatic dispersion in fibre-optic microwave and millimeter-wave links

    DEFF Research Database (Denmark)

    Gliese, Ulrik Bo; Nielsen, Søren Nørskov; Nielsen, Søren Nørskov

    1996-01-01

    Chromatic dispersion significantly limits the distance and/or frequency in fibre-optic microwave and millimeter-wave links based on direct detection due to a decrease of the carrier to noise ratio. The limitations in links based on coherent remote heterodyne detection, however, are far less signi...

  11. Limitations in distance and frequency due to chromatic dispersion in fibre-optic microwave and millimeter-wave links

    OpenAIRE

    Gliese, Ulrik Bo; Nielsen, Søren Nørskov; Nielsen, Søren Nørskov

    1996-01-01

    Chromatic dispersion significantly limits the distance and/or frequency in fibre-optic microwave and millimeter-wave links based on direct detection due to a decrease of the carrier to noise ratio. The limitations in links based on coherent remote heterodyne detection, however, are far less significant, and are primarily due to an increase of the phase noise

  12. Corrosion product characterisation by fibre optic raman spectroscopy

    International Nuclear Information System (INIS)

    Guzonas, D.A.; Rochefort, P.A.; Turner, C.W.

    1998-01-01

    Fibre optic Raman spectroscopy has been used to characterise secondary-side deposits removed from CANDU steam generators. The deposits examined were in the form of powders, millimetre-sized flakes, and deposits on the surfaces of pulled steam generator tubes. The compositions of the deposits obtained using Raman spectroscopy are similar to the compositions obtained using other ex-situ analytical techniques. A semi-quantitative estimate of amounts of the major components can be obtained from the spectra. It was noted that the signal-to-noise ratio of the Raman spectra decreased as the amount of magnetite in the deposit increased, as a result of absorption of the laser light by the magnetite. The conversion of magnetite to hematite by the laser beam was observed when high laser powers were used. The Raman spectra of larger flake samples clearly illustrate the inhomogeneous nature of the deposits. (author)

  13. Contact microphone using optical fibre Bragg grating technology

    International Nuclear Information System (INIS)

    Bezombes, F A; Lalor, M J; Burton, D R

    2007-01-01

    A contact microphone using optical fibre Bragg grating has been developed. It enables one to listen and record a human voice and/or breathing by monitoring the vibration generated by the outer wall of the throat during speech. This system can have many applications such as detecting defects in vocal folds, measuring and monitoring the vibration and defection generated by intubations of a patient throat and other voice related problem, low level speaking recording and transmitting is also possible, the microphone can be also used to monitor breathing and the system can be used as a microphone in very harsh environments for example it would allow one to hear the patient during a cat scan

  14. Analysis of distributed optical fibre acoustic sensors through numerical modelling.

    Science.gov (United States)

    Masoudi, Ali; Newson, Trevor P

    2017-12-11

    A distributed optical fibre acoustic sensor is numerically modelled. To increase the flexibility of the model, the building blocks of the sensing system are modelled separately and later combined to form the numerical model. This approach is adopted to facilitate the evaluation of each of the individual building blocks and their effects on the output of the sensor. The numerical model is used to assess the effect of parameters such as the linewidth of the laser source, the width of the probe pulse, and the frequency and amplitude of perturbation on the response of the sensing system. It is shown that the precision and accuracy of the sensing system are affected by the frequency and amplitude of perturbation as well as the pulse width and linewidth of the probe pulse.

  15. Real-time locating and speed measurement of fibre fuse using optical frequency-domain reflectometry.

    Science.gov (United States)

    Jiang, Shoulin; Ma, Lin; Fan, Xinyu; Wang, Bin; He, Zuyuan

    2016-05-05

    We propose and experimentally demonstrate real-time locating and speed measurement of fibre fuse by analysing the Doppler shift of reflected light using optical frequency-domain reflectometry (OFDR). Our method can detect the start of a fibre fuse within 200 ms which is equivalent to a propagation distance of about 10 cm in standard single-mode fibre. We successfully measured instantaneous speed of propagating fibre fuses and observed their subtle fluctuation owing to the laser power instability. The resolution achieved for speed measurement in our demonstration is 1 × 10(-3) m/s. We studied the fibre fuse propagation speed dependence on the launched power in different fibres. Our method is promising for both real time fibre fuse monitoring and future studies on its propagation and termination.

  16. Optic nerve head and fibre layer imaging for diagnosing glaucoma

    Science.gov (United States)

    Michelessi, Manuele; Lucenteforte, Ersilia; Oddone, Francesco; Brazzelli, Miriam; Parravano, Mariacristina; Franchi, Sara; Ng, Sueko M; Virgili, Gianni

    2016-01-01

    Background The diagnosis of glaucoma is traditionally based on the finding of optic nerve head (ONH) damage assessed subjectively by ophthalmoscopy or photography or by corresponding damage to the visual field assessed by automated perimetry, or both. Diagnostic assessments are usually required when ophthalmologists or primary eye care professionals find elevated intraocular pressure (IOP) or a suspect appearance of the ONH. Imaging tests such as confocal scanning laser ophthalmoscopy (HRT), optical coherence tomography (OCT) and scanning laser polarimetry (SLP, as used by the GDx instrument), provide an objective measure of the structural changes of retinal nerve fibre layer (RNFL) thickness and ONH parameters occurring in glaucoma. Objectives To determine the diagnostic accuracy of HRT, OCT and GDx for diagnosing manifest glaucoma by detecting ONH and RNFL damage. Search methods We searched several databases for this review. The most recent searches were on 19 February 2015. Selection criteria We included prospective and retrospective cohort studies and case-control studies that evaluated the accuracy of OCT, HRT or the GDx for diagnosing glaucoma. We excluded population-based screening studies, since we planned to consider studies on self-referred people or participants in whom a risk factor for glaucoma had already been identified in primary care, such as elevated IOP or a family history of glaucoma. We only considered recent commercial versions of the tests: spectral domain OCT, HRT III and GDx VCC or ECC. Data collection and analysis We adopted standard Cochrane methods. We fitted a hierarchical summary ROC (HSROC) model using the METADAS macro in SAS software. After studies were selected, we decided to use 2 × 2 data at 0.95 specificity or closer in meta-analyses, since this was the most commonly-reported level. Main results We included 106 studies in this review, which analysed 16,260 eyes (8353 cases, 7907 controls) in total. Forty studies (5574

  17. Photon Irradiation Response on Ge and Al-Doped SiO2 Optical Fibres

    Science.gov (United States)

    Yaakob, Nor Haliza; Wagiran, Husin; Ramli, Ahmad Termizi; Ali, Hassan; Asni, Hazila

    2010-07-01

    Recently, research groups have reported a number of radiation effects on the applications of SiO2 optical fibres with possible use as dosimeter material because these optical fibre provide a good basis for medical radiation dosimetry. The objective of this study is to investigate the thermoluminescence response and fading characteristic for germanium and aluminium doped SiO2 optical fibres with photon irradiation. These optical fibres are placed in solid phantom and irradiated to 6 and 10 MV photon beam at dose ranging from 0.06 Gy to 0.24 Gy using Primus MLC 3339 linear accelerator at Hospital Sultan Ismail, Johor Bahru. In fading studies, the TL measurements were continued up to 14 days period. The optical fibres will produce glow curves whereby the information is then analyzed. Al and Ge-doped optical fibres have a linear dose-TL signal relationship that is proportionality between the TL signal and the doses. Comparison for TL response between different linear accelerator showed a good agreement because these optical fibres also have a linear dose-TL signal relationship even using different equipments.

  18. Air-structured optical fibre drawn from a 3D-printed preform

    OpenAIRE

    Cook, Kevin; Canning, John; Leon-Saval, Sergio; Reid, Zane; Hossain, Md Arafat; Comatti, Jade-Edouard; Luo, Yanhua; Peng, Gang-Ding

    2016-01-01

    A structured optical fibre is drawn from a 3D-printed structured preform. Preforms containing a single ring of holes around the core are fabricated using filament made from a modified butadiene polymer. More broadly, 3D printers capable of processing soft glasses, silica and other materials are likely to come on line in the not-so distant future. 3D printing of optical preforms signals a new milestone in optical fibre manufacture.

  19. Optical fibre probes in the measurement of scattered light

    Indian Academy of Sciences (India)

    2014-01-08

    Jan 8, 2014 ... An optrode usually comprises a bundle of multimode fibres, out of which one or more fibres are used for irradiating the sample, and the remaining fibres are used to collect the light reflected/scattered/fluoresced from the sample containing the measurand(s). The so-collected light carries the characteristic ...

  20. A Fibre Bragg Grating Interrogation Technique Based on High Birefringence Fibre Loop Mirror and WDM

    Directory of Open Access Journals (Sweden)

    Zhang Xun

    2016-01-01

    Full Text Available In this paper, a fibre Bragg grating (FBG interrogation technique based on high Birefringence fibre loop mirror (Hi-Bi FLM and wavelength division multiplexer (WDM is proposed and demonstrated. The approximate linear edge of the transmittance of the Hi-Bi FLM, which is a sinusoidal function of wavelength, is used to interrogate the sensing FBGs and WDMs is used to realize wavelength discrimination .Suitable for both static and dynamic sensing, this interrogation method has the advantages of all fibre design and high stability.

  1. Numerical analysis on using compound parabolic couplers for direct transmission of concentrated solar radiation via optical fibre (Conference Presentation)

    Science.gov (United States)

    Rahou, Maryam; Andrews, John; Rosengarten, Gary

    2016-09-01

    A challenge in high-temperature solar thermal applications is transfer of concentrated solar radiation to the load with minimum energy loss. The use of a solar concentrator in conjunction with optical fibres has potential advantages in terms of transmission efficiency, technical feasibility and cost-effectiveness compared to a conventional heat transfer system employing heat exchangers and a heat transfer fluid. For transferring higher levels of concentrated flux it is necessary to employ multiple optical fibres or fibre bundles. However, the losses at the incident plane of a bundle due to absorption by the epoxy and cladding between the individual fibres in a bundle are substantial, typically over 60% of the overall transmission loss. The optical transmission of the system can thus be enhanced by employing a coupler between the concentrated solar radiation and the entrance to the bundle that reflects all incident light into the cores of individual fibres rather than allowing it to strike the interstitial spaces between the cores. This paper describes the design for such couplers based on multiple compound parabolic (CP) reflectors each with its exit aperture coinciding with the core of an individual fibre within the bundle. The proposed design employs external reflection from a machined metallic aluminium surface. This CP arrangement has the additional benefit of increasing the concentration ratio of the primary solar concentrator used. Simulation modeling using LightTools is conducted into a parabolic Cassegrain solar concentrator employing these CP couplers prior to a fibre bundle. The dependence of overall transmission and total optical efficiency of the system over lengths of the bundle up to 100 m are investigated quantitatively. In addition, the influence on transmission of the angular distribution of radiation intensity at the aperture of the couplers is studied.

  2. Chemical stability of prints made on hemp fibre based papers

    Directory of Open Access Journals (Sweden)

    Ivana Plazonić

    2016-11-01

    Full Text Available For paper industry and consequently graphic industry it is very important that fibres used in paper production provide high quality and printability of the paper. In pulp and paper industry fibres of cellulose pulp derived still predominantly from wood, but in the last few years the consumption of non-wood raw materials for that purpose has grown. This work presents research on the chemical stability of printed hemp fibre based papers to water, alcohol and alkali. Evaluation of chemical degradation on prints was determined through the spectrophotometric measurements. Deviations in colour of prints have shown that highest chemical stability provides prints made on industrially paper formed from mixture of hemp and post-consumer fibres with high share of inorganic components. Further, bleached hemp fibres in handmade 100 % hemp fibre based paper give prints with the lowest chemical stability.

  3. EDITORIAL: The 20th International Conference on Optical Fibre Sensors, OFS-20 The 20th International Conference on Optical Fibre Sensors, OFS-20

    Science.gov (United States)

    Culshaw, Brian; Ecke, Wolfgang; Jones, Julian; Tatam, Ralph; Willsch, Reinhardt

    2010-09-01

    Welcome to our special issue on fibre optic sensors. Fibre optic sensors were first suggested in the patent literature in the mid 1960s as an innovative means for making measurements. This proposed a surface finish measurement tool with high precision and resulted in an instrument that remains available today. Much has happened since, with significant innovation in the techniques through which light propagating whilst guided in a fibre can be unambiguously, repeatedly and predictably modulated in response to an external phenomenon. The technique offers not only the precision mentioned earlier but also inherent electromagnetic immunity, the capability to sense at long distances, light weight, small size and a multiplicity of network architectures, all of which can be interrogated from a single point. Even so, fibre sensors is a niche technology, attractive only when its very special features offer substantial user benefit. There are, however, many such niches exemplified in the electrical power supply industry, in gyroscopes for navigational instruments, in hydrophones and geophones. Then there are the distributed sensing architectures that enable useful measurements of pressure, strain and temperature fields affecting the optical properties of the fibre itself to map these parameter fields as a function of position along lengths of fibre to many tens of kilometres. The fibre sensing concept spawned its own research community, and the international conference on Optical Fibre Sensors first appeared in 1983 in London then emerged into a series travelling from Europe to the Americas and into the Asia-Pacific region. The 20th in the series took place in Edinburgh at the end of 2009 and this special issue of Measurement Science and Technology presents extended versions of some of the papers that first appeared at the conference. The science and technology of fibre sensing have evolved significantly over the history of the conference, drawing on developments in optical

  4. Whispering Gallery Modes in Standard Optical Fibres for Fibre Profiling Measurements and Sensing of Unlabelled Chemical Species

    Directory of Open Access Journals (Sweden)

    Anna Boleininger

    2010-03-01

    Full Text Available Whispering gallery mode resonances in liquid droplets and microspheres have attracted considerable attention due to their potential uses in a range of sensing and technological applications. We describe a whispering gallery mode sensor in which standard optical fibre is used as the whispering gallery mode resonator. The sensor is characterised in terms of the response of the whispering gallery mode spectrum to changes in resonator size, refractive index of the surrounding medium, and temperature, and its measurement capabilities are demonstrated through application to high-precision fibre geometry profiling and the detection of unlabelled biochemical species. The prototype sensor is capable of detecting unlabelled biomolecular species in attomole quantities.

  5. Whispering gallery modes in standard optical fibres for fibre profiling measurements and sensing of unlabelled chemical species.

    Science.gov (United States)

    Boleininger, Anna; Lake, Thomas; Hami, Sophia; Vallance, Claire

    2010-01-01

    Whispering gallery mode resonances in liquid droplets and microspheres have attracted considerable attention due to their potential uses in a range of sensing and technological applications. We describe a whispering gallery mode sensor in which standard optical fibre is used as the whispering gallery mode resonator. The sensor is characterised in terms of the response of the whispering gallery mode spectrum to changes in resonator size, refractive index of the surrounding medium, and temperature, and its measurement capabilities are demonstrated through application to high-precision fibre geometry profiling and the detection of unlabelled biochemical species. The prototype sensor is capable of detecting unlabelled biomolecular species in attomole quantities.

  6. Laser-tuned whispering gallery modes in a solid-core microstructured optical fibre integrated with magnetic fluids.

    Science.gov (United States)

    Lin, Wei; Zhang, Hao; Liu, Bo; Song, Binbin; Li, Yuetao; Yang, Chengkun; Liu, Yange

    2015-12-03

    A laser-assisted tuning method of whispering gallery modes (WGMs) in a cylindrical microresonator based on magnetic-fluids-infiltrated microstructured optical fibres (MFIMOFs, where MF and MOF respectively refer to magnetic fluid and microstructured optical fibre) is proposed, experimentally demonstrated and theoretically analysed in detail. The MFIMOF is prepared by infiltrating the air-hole array of the MOF using capillary action effect. A fibre-coupling system is set up for the proposed MFIMOF-based microresonator to acquire an extinction ratio up to 25 dB and a Q-factor as large as 4.0 × 10(4). For the MF-infiltrated MOF, the light propagating in the fibre core region would rapidly spread out and would be absorbed by the MF-rod array cladding to induce significant thermal effect. This has been exploited to achieve a WGM resonance wavelength sensitivity of 0.034 nm/mW, which is ~20 times higher than it counterpart without MF infiltration. The wavelength response of the resonance dips exhibit linear power dependence, and owing to such desirable merits as ease of fabrication, high sensitivity and laser-assisted tunability, the proposed optical tuning approach of WGMs in the MFIMOF would find promising applications in the areas of optical filtering, sensing, and signal processing, as well as future all-optical networking systems.

  7. Rheology of Carbon Fibre Reinforced Cement-Based Mortar

    International Nuclear Information System (INIS)

    Banfill, Phillip F. G.; Starrs, Gerry; McCarter, W. John

    2008-01-01

    Carbon fibre reinforced cement based materials (CFRCs) offer the possibility of fabricating 'smart' electrically conductive materials. Rheology of the fresh mix is crucial to satisfactory moulding and fresh CFRC conforms to the Bingham model with slight structural breakdown. Both yield stress and plastic viscosity increase with increasing fibre length and volume concentration. Using a modified Viskomat NT, the concentration dependence of CFRC rheology up to 1.5% fibre volume is reported

  8. Some fundamental problems relating to optical fibres. I. The attainment of loss coefficients of 10-5cm-1

    International Nuclear Information System (INIS)

    Gambling, W.A.

    1977-01-01

    Fibres for optical communications are currently being made with two types of material, namely low-temperature compound glasses and high-temperature silica-based glasses. The paper outlines the techniques used in the two cases and summarizes the results which have so far been achieved. (author)

  9. Multimode laser emission from dye-doped hollow polymer optical fibre

    Indian Academy of Sciences (India)

    2014-02-09

    Feb 9, 2014 ... Dye-doped polymer optical fibre preforms were fabricated by the controlled polymeriza- tion of Rh B-doped methyl methacrylate (MMA). Hole in the preform can be achieved by placing a teflon rod on the centre of the glass tube during the polymerization. Final fibre structure with required diameter was ...

  10. Optical properties of bismuth-doped silica fibres in the temperature range 300 — 1500 K

    International Nuclear Information System (INIS)

    Dvoretskii, D A; Bufetov, Igor' A; Vel'miskin, V V; Zlenko, Alexander S; Khopin, V F; Semjonov, S L; Guryanov, Aleksei N; Denisov, L K; Dianov, Evgenii M

    2012-01-01

    The visible and near-IR absorption and luminescence bands of bismuth-doped silica and germanosilicate fibres have been measured for the first time as a function of temperature. The temperature-dependent IR luminescence lifetime of a bismuth-related active centre associated with silicon in the germanosilicate fibre has been determined. The Bi 3+ profile across the silica fibre preform is shown to differ markedly from the distribution of IR-emitting bismuth centres associated with silicon. The present results strongly suggest that the IR-emitting bismuth centre comprises a lowvalence bismuth ion and an oxygen-deficient glass network defect. (optical fibres, lasers and amplifiers. properties and applications)

  11. Nonlinear Pulse Shaping in Fibres for Pulse Generation and Optical Processing

    Directory of Open Access Journals (Sweden)

    Sonia Boscolo

    2012-01-01

    Full Text Available The development of new all-optical technologies for data processing and signal manipulation is a field of growing importance with a strong potential for numerous applications in diverse areas of modern science. Nonlinear phenomena occurring in optical fibres have many attractive features and great, but not yet fully explored, potential in signal processing. Here, we review recent progress on the use of fibre nonlinearities for the generation and shaping of optical pulses and on the applications of advanced pulse shapes in all-optical signal processing. Amongst other topics, we will discuss ultrahigh repetition rate pulse sources, the generation of parabolic shaped pulses in active and passive fibres, the generation of pulses with triangular temporal profiles, and coherent supercontinuum sources. The signal processing applications will span optical regeneration, linear distortion compensation, optical decision at the receiver in optical communication systems, spectral and temporal signal doubling, and frequency conversion.

  12. Scintillating optical fibres and the detection of very short lived particles

    International Nuclear Information System (INIS)

    Fisher, C.M.

    1985-01-01

    The application of scintillating fiber optics to the problem of heavy flavour particle detection in both fixed target and collider experiments is reviewed. Brief specifications for both fibres and read-out systems are given. (orig.)

  13. Optical fibre sensors: their role in in vivo dosimetry for prostate cancer radiotherapy.

    Science.gov (United States)

    Woulfe, P; Sullivan, F J; O'Keeffe, S

    2016-01-01

    Review is made of dosimetric studies of current optical fibre technology in radiotherapy for therapeutic applications, focusing particularly on in vivo dosimetry for prostate radiotherapy. We present the various sensor designs along with the main advantages and disadvantages associated with this technology. Optical fibres are ideally placed for applications in radiotherapy dosimetry; due to their small size they are lightweight and immune to electromagnetic interferences. The small dimensions of optical fibres allows it to be easily guided within existing brachytherapy equipment; for example, within the seed implantation needle for direct tumour dose analysis, in the urinary catheter to monitor urethral dose, or within the biopsy needle holder of the transrectal ultrasound probe to monitor rectal wall dose. The article presents the range of optical fibre dosimeter designs along with the main dosimetric properties required for a modern in vivo dosimetry system to be utilised in a clinical environment.

  14. Distributed optical fibre sensing for early detection of shallow landslides triggering.

    Science.gov (United States)

    Schenato, Luca; Palmieri, Luca; Camporese, Matteo; Bersan, Silvia; Cola, Simonetta; Pasuto, Alessandro; Galtarossa, Andrea; Salandin, Paolo; Simonini, Paolo

    2017-10-31

    A distributed optical fibre sensing system is used to measure landslide-induced strains on an optical fibre buried in a large scale physical model of a slope. The fibre sensing cable is deployed at the predefined failure surface and interrogated by means of optical frequency domain reflectometry. The strain evolution is measured with centimetre spatial resolution until the occurrence of the slope failure. Standard legacy sensors measuring soil moisture and pore water pressure are installed at different depths and positions along the slope for comparison and validation. The evolution of the strain field is related to landslide dynamics with unprecedented resolution and insight. In fact, the results of the experiment clearly identify several phases within the evolution of the landslide and show that optical fibres can detect precursory signs of failure well before the collapse, paving the way for the development of more effective early warning systems.

  15. Surface topography of machined fibre reinforced plastics obtained by stylus instruments and optical profilometers

    DEFF Research Database (Denmark)

    Eriksen, Else; Hansen, Hans Nørgaard

    1998-01-01

    by stylus instruments and by optical profilometers. The measurements were performed on machined surfaces with three distinct different roughness levels. The materials were two thermoplastics, polyoxymethylene and polypropylene, reinforced with short glass fibres. The two stylus instruments gave almost...

  16. Fibre Bragg Grating and Long Period Grating Sensors in Polymer Optical Fibres

    DEFF Research Database (Denmark)

    Bundalo, Ivan-Lazar

    in ΔΛfast. It would have the highest sensing range around 3%. In the last part of the FBG section, a simple fibre FBG microphone is investigated, and the influence of a membrane amplifier on sound detection is also investigated. In the last part of the thesis the LPG inscription system is shown...... which translates the outside pressure into strain on the fibre. The transducer consisted of a 3Dprinted skeleton through which the fibre is pulled. A latex material is then wrapped around it and all the holes were sealed in order to prevent the air from leaking out. The pod transducer was tested...

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

    Science.gov (United States)

    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.

  18. A set-up to measure the optical attenuation length of scintillating fibres

    CERN Document Server

    Alfieri, C; Joram, C

    2015-01-01

    The optical attenuation length of a scintillating fibre characterizes the quality of light transport through the fibre. It relates directly to the quantity of detectable light at the readout end of the fibre. An optical bench has been constructed, which allows excitation of the fibre at various distances from the photodetector. Depending on the choice of the photodetector – Si-PIN photodiode or grating spectrometer – the attenuation length is measured as weighted average over the sensitivity of the photodetector or as a spectral distribution. A few examples illustrate its operation and performance. The set-up serves for fibre optimisation in the R&D phase and is expected to be used for systematic checks during the series production phase of the LHCb SciFi tracker project.

  19. An optimal method for producing low-stress fibre optic cables for astronomy

    Science.gov (United States)

    Murray, Graham; Tamura, Naoyuki; Takato, Naruhisa; Ekpenyong, Paul; Jenkins, Daniel; Leeson, Kim; Trezise, Shaun; Butterley, Timothy; Gunn, James; Ferreira, Decio; Oliveira, Ligia; Sodre, Laerte

    2017-09-01

    An increasing number of astronomical spectrographs employ optical fibres to collect and deliver light. For integral-field and high multiplex multi-object survey instruments, fibres offer unique flexibility in instrument design by enabling spectrographs to be located remotely from the telescope focal plane where the fibre inputs are deployed. Photon-starved astronomical observations demand optimum efficiency from the fibre system. In addition to intrinsic absorption loss in optical fibres, another loss mechanism, so-called focal ratio degradation (FRD) must be considered. A fundamental cause of FRD is stress, therefore low stress fibre cables that impart minimum FRD are essential. The FMOS fibre instrument for Subaru Telescope employed a highly effective cable solution developed at Durham University. The method has been applied again for the PFS project, this time in collaboration with a company, PPC Broadband Ltd. The process, planetary stranding, is adapted from the manufacture of large fibre-count, large diameter marine telecommunications cables. Fibre bundles describe helical paths through the cable, incorporating additional fibre per unit length. As a consequence fibre stress from tension and bend-induced `race-tracking' is minimised. In this paper stranding principles are explained, covering the fundamentals of stranded cable design. The authors describe the evolution of the stranding production line and the numerous steps in the manufacture of the PFS prototype cable. The results of optical verification tests are presented for each stage of cable production, confirming that the PFS prototype performs exceptionally well. The paper concludes with an outline of future on-telescope test plans.

  20. Full Spectrum Diffused and Beamed Solar Energy Application Using Optical Fibre

    OpenAIRE

    Majumdar, M. R. Dutta; Das, Debasish

    2007-01-01

    Existing solar energy application systems use small fraction of full spectrum of solar energy. So attempts are made to show how full spectrum solar energy can be used for diffused and beamed form of incident solar energy. Luminescent Solar Concentrator (LSC) principle with optical fibre in diffused sun light and dielectric mirror separation technique with optical fibre in beamed form are discussed. Comparison of both the cases are done. Keywords: full spectrum, solar photonics, diffused solar...

  1. Periodic refractive index modifications inscribed in polymer optical fibre by focussed IR femtosecond pulses

    DEFF Research Database (Denmark)

    Stecher, Matthias; Williams, Robert J.; Bang, Ole

    Focussed femtosecond laser pulses were used to inscribe a periodic array of modifications in the core of a polymer optical fibre. Structural and refractive-index modifications have been observed at different pulse energies using DIC microscopy.......Focussed femtosecond laser pulses were used to inscribe a periodic array of modifications in the core of a polymer optical fibre. Structural and refractive-index modifications have been observed at different pulse energies using DIC microscopy....

  2. Towards efficient real-time submarine power cable monitoring using distributed fibre optic acoustic sensors

    Science.gov (United States)

    Hicke, Konstantin; Krebber, Katerina

    2017-04-01

    Online condition monitoring of submarine power cables helps to avert failures and damages produced by mechanical impacts. We report, to our knowledge for the first time, on investigations regarding the feasibility of distributed fiber optic acoustic sensors based on C-OTDR, with the sensor fibers being embedded in the cable, to detect vibrations due to mechanical disturbances along the cable. We present first results of sensing experiments where acoustic signals are transmitted through water to simulate the corresponding submarine conditions. Furthermore, we show results evaluating the usefulness of fibre commonly embedded in existing power cable designs for our sensing purposes.

  3. Unlocking high spatial resolution in neutron imaging through an add-on fibre optics taper.

    Science.gov (United States)

    Morgano, M; Trtik, P; Meyer, M; Lehmann, E H; Hovind, J; Strobl, M

    2018-01-22

    The demand for high resolution neutron imaging has been steadily increasing over the past years. The number of facilities offering cutting edge resolution is however limited, due to (i) the design complexity of an optimized device able to reach a resolution in the order of ≈ 10 μm and (ii) limitations in available neutron flux. Here we propose a simple addition, based on a Fibre Optics Taper (FOT), that can be easily attached to an already existing scintillator-camera imaging detector in order to efficiently increase its spatial resolution and hence boost the capability of an instrument into high resolution applications.

  4. Investigation of the in-solution relaxation of polymer optical fibre Bragg gratings

    DEFF Research Database (Denmark)

    Fasano, Andrea; Woyessa, Getinet; Janting, Jakob

    2016-01-01

    We investigate the response of PMMA microstructured polymer optical fibre Bragg gratings whenimmersed in methanol/water solutions. Overall we observe a permanent blue-shift in Bragg gratingwavelength after solvent evaporation. The main contribution in the resonance wavelength shift probably...... arisesfrom a permanent change in the size of the fibre, as already reported for high-temperature annealing ofpolymer optical fibres. As a consequence of the solution concentration dependence of the glass transitiontemperature of polymers, different methanol/water solutions lead to various degrees of frozen...

  5. A guiding light: spectroscopy on digital microfluidic devices using in-plane optical fibre waveguides.

    Science.gov (United States)

    Choi, Kihwan; Mudrik, Jared M; Wheeler, Aaron R

    2015-09-01

    We present a novel method for in-plane digital microfluidic spectroscopy. In this technique, a custom manifold (.stl file available online as ESM) aligns optical fibres with a digital microfluidic device, allowing optical measurements to be made in the plane of the device. Because of the greater width vs thickness of a droplet on-device, the in-plane alignment of this technique allows it to outperform the sensitivity of vertical absorbance measurements on digital microfluidic (DMF) devices by ∼14×. The new system also has greater calibration sensitivity for thymol blue measurements than the popular NanoDrop system by ∼2.5×. The improvements in absorbance sensitivity result from increased path length, as well as from additional effects likely caused by liquid lensing, in which the presence of a water droplet between optical fibres increases fibre-to-fibre transmission of light by ∼2× through refraction and internal reflection. For interrogation of dilute samples, stretching of droplets using digital microfluidic electrodes and adjustment of fibre-to-fibre gap width allows absorbance path length to be changed on-demand. We anticipate this new digital microfluidic optical fibre absorbance and fluorescence measurement system will be useful for a wide variety of analytical applications involving microvolume samples with digital microfluidics.

  6. Integrity Testing of Pile Cover Using Distributed Fibre Optic Sensing

    Directory of Open Access Journals (Sweden)

    Yi Rui

    2017-12-01

    Full Text Available The integrity of cast-in-place foundation piles is a major concern in geotechnical engineering. In this study, distributed fibre optic sensing (DFOS cables, embedded in a pile during concreting, are used to measure the changes in concrete curing temperature profile to infer concrete cover thickness through modelling of heat transfer processes within the concrete and adjacent ground. A field trial was conducted at a high-rise building construction site in London during the construction of a 51 m long test pile. DFOS cables were attached to the reinforcement cage of the pile at four different axial directions to obtain distributed temperature change data along the pile. The monitoring data shows a clear development of concrete hydration temperature with time and the pattern of the change varies due to small changes in concrete cover. A one-dimensional axisymmetric heat transfer finite element (FE model is used to estimate the pile geometry with depth by back analysing the DFOS data. The results show that the estimated pile diameter varies with depth in the range between 1.40 and 1.56 m for this instrumented pile. This average pile diameter profile compares well to that obtained with the standard Thermal Integrity Profiling (TIP method. A parametric study is conducted to examine the sensitivity of concrete and soil thermal properties on estimating the pile geometry.

  7. Raman-Enhanced Phase-Sensitive Fibre Optical Parametric Amplifier

    Science.gov (United States)

    Fu, Xuelei; Guo, Xiaojie; Shu, Chester

    2016-01-01

    Phase-sensitive amplification is of great research interest owing to its potential in noiseless amplification. One key feature in a phase-sensitive amplifier is the gain extinction ratio defined as the ratio of the maximum to the minimum gains. It quantifies the capability of the amplifier in performing low-noise amplification for high phase-sensitive gain. Considering a phase-sensitive fibre optical parametric amplifier for linear amplification, the gain extinction ratio increases with the phase-insensitive parametric gain achieved from the same pump. In this work, we use backward Raman amplification to increase the phase-insensitive parametric gain, which in turn improves the phase-sensitive operation. Using a 955 mW Raman pump, the gain extinction ratio is increased by 9.2 dB. The improvement in the maximum phase-sensitive gain is 18.7 dB. This scheme can significantly boost the performance of phase-sensitive amplification in a spectral range where the parametric pump is not sufficiently strong but broadband Raman amplification is available. PMID:26830136

  8. Integrity Testing of Pile Cover Using Distributed Fibre Optic Sensing

    Science.gov (United States)

    Rui, Yi; Kechavarzi, Cedric; O’Leary, Frank; Barker, Chris; Nicholson, Duncan; Soga, Kenichi

    2017-01-01

    The integrity of cast-in-place foundation piles is a major concern in geotechnical engineering. In this study, distributed fibre optic sensing (DFOS) cables, embedded in a pile during concreting, are used to measure the changes in concrete curing temperature profile to infer concrete cover thickness through modelling of heat transfer processes within the concrete and adjacent ground. A field trial was conducted at a high-rise building construction site in London during the construction of a 51 m long test pile. DFOS cables were attached to the reinforcement cage of the pile at four different axial directions to obtain distributed temperature change data along the pile. The monitoring data shows a clear development of concrete hydration temperature with time and the pattern of the change varies due to small changes in concrete cover. A one-dimensional axisymmetric heat transfer finite element (FE) model is used to estimate the pile geometry with depth by back analysing the DFOS data. The results show that the estimated pile diameter varies with depth in the range between 1.40 and 1.56 m for this instrumented pile. This average pile diameter profile compares well to that obtained with the standard Thermal Integrity Profiling (TIP) method. A parametric study is conducted to examine the sensitivity of concrete and soil thermal properties on estimating the pile geometry. PMID:29257094

  9. Compaction in optical fibres and fibre Bragg gratings under nuclear reactor high neutron and gamma fluence

    Energy Technology Data Exchange (ETDEWEB)

    Remy, L.; Cheymol, G. [CEA, French Nuclear Energy Commission, Nuclear Energy Division, DPC/SEARS/LISL Bat 467 CEA Saclay 91191 Gif/Yvette Cedex (France); Gusarov, A. [SCK.CEN - Belgian Nuclear Research center, Boeretang 200 2400 Mol (Belgium); Morana, A.; Marin, E.; Girard, S. [Universite de Saint-Etienne, Laboratoire Hubert Curien, UMR CNRS5516, 18, rue du Pr. Lauras, F-42000 Saint-Etienne (France)

    2015-07-01

    In the framework of the development by CEA and SCK.CEN of a Fabry Perot Sensor (FPS) able to measure dimensional changes in Material Testing Reactor (MTR), the first goal of the SAKE 1 (Smirnof extention - Additional Key-tests on Elongation of glass fibres) irradiation was to measure the linear compaction of single mode fibres under high fast neutron fluence. Indeed, the compaction of the fibre which forms one side of the Fabry Perot cavity, may in particular cause a noticeable measurement error. An accurate quantification of this effect is then required to predict the radiation-induced drift and optimize the sensor design. To achieve this, an innovative approach was used. Approximately seventy uncoated fibre tips (length: 30 to 50 mm) have been prepared from several different fibre samples and were installed in the SCK.CEN BR2 reactor (Mol Belgium). After 22 days of irradiation a total fast (E > 1 MeV) fluence of 3 to 5x10{sup 19} n{sub fast}/cm{sup 2}, depending on the sample location, was accumulated. The temperature during irradiation was 291 deg. C, which is not far from the condition of the intended FPS use. A precise measurement of each fibre tip length was made before the irradiation and compared to the post irradiation measurement highlighting a decrease of the fibres' length corresponding to about 0.25% of linear compaction. The amplitude of the changes is independent of the capsule, which could mean that the compaction effect saturates even at the lowest considered fluence. In the prospect of performing distributed temperature measurement in MTR, several fibre Bragg gratings written using a femtosecond laser have been also irradiated. All the gratings were written in radiation hardened fibres, and underwent an additional treatment with a procedure enhancing their resistance to ionizing radiations. A special mounting made it possible to test the reflection and the transmission of the gratings on fibre samples cut down to 30 to 50 mm. The comparison

  10. Effect of the preform fabrication process on the properties of all-silica optical fibres

    Science.gov (United States)

    Grishchenko, A. B.

    2017-12-01

    In this paper, we present a detailed comparison of technical capabilities of processes for the fabrication of all-silica optical fibre preforms with the use of an atmospheric pressure radio frequency plasma (POVD process) and low-pressure microwave plasma (PCVD process) and analyse the origin of the difference in optical properties between fibres produced by these methods. It is shown that the higher temperature of the core material and the higher oxygen partial pressure in preform fabrication by the POVD process lead to an increase in optical losses in the visible and UV spectral regions in the silica fibres with low hydroxyl (OH) content and a decrease in the solarisation resistance of the fibres with high OH content, i.e. to a more rapid increase in background losses in response to UV irradiation. No such drawbacks are detected in the case of the growth of reflective layers by the PCVD process.

  11. HF-based clad etching of fibre Bragg grating and its utilization in ...

    Indian Academy of Sciences (India)

    2014-02-09

    Feb 9, 2014 ... removed using HF-based etching to make FBG sensitive to changes in the surrounding refractive index. ... Bragg peak shifted almost linearly from 1534.056 nm to 1534.162 nm as surrounding dye concen- tration in ... Various fibre-optic sensors have been proposed for physical, chemical and biological.

  12. Central Tracking Detector Based on Scintillating Fibres

    CERN Multimedia

    2002-01-01

    Scintillating fibres form a reasonable compromise for central tracking detectors in terms of price, resolution, response time, occupancy and heat production. \\\\ \\\\ New fluorescents with large Stokes shifts have been produced, capable of working without wavelength shifters. Coherent multibundles have been developed to achieve high packing fractions. Small segments of tracker shell have been assembled and beam tests have confirmed expectations on spatial resolution. An opto-electronic delay line has been designed to delay the track patterns and enable coincidences with a first level trigger. Replacement of the conventional phosphor screen anode with a Si pixel chip is achieved. This tube is called ISPA-tube and has already been operated in beam tests with a scintillating fibres tracker. \\\\ \\\\ The aim of the proposal is to improve hit densities for small diameter fibres by increasing the fraction of trapped light, by reducing absorption and reflection losses, by reflecting light at the free fibre end, and by inc...

  13. The effect of mechanical drawing on optical and structural properties of nylon 6 fibres

    Science.gov (United States)

    El-Bakary, M. A.

    2007-09-01

    The Pluta polarizing double-refracting interference microscope was attached to a mechanical drawing device to study the effect of cold drawing on the optical and structural properties of nylon 6 fibres. The microscope was used in its two positions for determining the refractive indices and birefringence of fibres. Different applied stresses and strain rates were obtained using the mechanical-drawing device. The effect of the applied stresses on the optical and physical parameters was investigated. The resulting optical parameters were utilized to investigate the polarizability per unit volume, the optical orientation factor, the orientation angle and the average work per chain. The refractive index and birefringence profiles were measured. Relationships between the average work per chain and optical parameters at different strains rates were determined. An empirical formula was deduced for these fibres. Micro-interferograms are given for illustration.

  14. Using a fibre-optic cable as Distributed Acoustic Sensor for Vertical Seismic Profiling - Overview of various field tests

    Science.gov (United States)

    Götz, Julia; Lüth, Stefan; Henninges, Jan; Reinsch, Thomas

    2015-04-01

    Fibre-optic Distributed Acoustic Sensing (DAS) or Distributed Vibration Sensing (DVS) is a technology, where an optical fibre cable is used as a sensor for acoustic signals. An ambient seismic wavefield, which is coupled by friction or pressure to the optical fibre, induces dynamic strain changes along the cable. The DAS/DVS technology offers the possibility to record an optoelectronic signal which is linearly related to the time dependent local strain. The DAS/DVS technology is based on the established technique of phase-sensitive optical time-domain reflectometry (phi-OTDR). Coherent laser pulses are launched into the fibre to monitor changes in the resulting elastic Rayleigh backscatter with time. Dynamic strain changes lead to small displacements of the scattering elements (non-uniformities within the glass structure of the optical fibre), and therefore to variations of the relative phases of the backscattered photons. The fibre behaves as a series of interferometers whose output is sensitive to small changes of the strain at any point along its length. To record the ground motion not only in space but also in time, snapshots of the wavefield are created by repeatedly firing laser pulses into the fibre at sampling frequencies much higher than seismic frequencies. DAS/DVS is used e.g. for continuous monitoring of pipelines, roads or borders and for production monitoring from within the wellbore. Within the last years, the DAS/DVS technology was further developed to record seismic data. We focus on the recording of Vertical Seismic Profiling (VSP) data with DAS/DVS and present an overview of various field tests published between 2011 and 2014. Here, especially CO2 storage pilot sites provided the opportunity to test this new technology for geophysical reservoir monitoring. DAS/DVS-VSP time-lapse measurements have been published for the Quest CO2 storage site in Canada. The DAS/DVS technology was also tested at the CO2 storage sites in Rousse (France), Citronelle

  15. Crack Growth Monitoring by Embedded Optical Fibre Bragg Grating Sensors: Fibre Reinforced Plastic Crack Growing Detection

    DEFF Research Database (Denmark)

    Pereira, Gilmar Ferreira; Mikkelsen, Lars Pilgaard; McGugan, Malcolm

    2015-01-01

    This article presents a novel method to asses a crack growing/damage event in fibre reinforced plastic, or adhesive using Fibre Bragg Grating (FBG) sensors embedded in a host material. Different features of the crack mechanism that induce a change in the FBG response were identified. Double...... Cantilever Beams specimens made with glass fibre glued with structural adhesive, were instrumented with an array of FBG sensors embedded in the material and tested using an experimental fracture procedure. A digital image correlation technique was used to determine the presence of the specific phenomena...... caused by the crack, and to correlate with the FBG sensor. A Material-Sensor model was developed in order to predict the sensor output response under a crack/delamination situation, which can be used as an analysis tool for future application of this measurement technology in more complex structures....

  16. A highly versatile optical fibre vacuum feed-through.

    Science.gov (United States)

    Davidson, Ian A; Azzouz, Hatim; Hueck, Klaus; Bourennane, Mohamed

    2016-05-01

    Coupling light into a vacuum system is a non-trivial problem, requiring the use of a specialized feed-through. This feed-through must be both leak tight and offer a low optical loss if it is to be suitable for general use. In this paper, we report on the development of an extremely simple yet versatile, low cost, demountable optical fiber vacuum feed-through based on the modification of a standard optical fiber bulkhead connector. The modified connector was found to have a leak rate of 6.6 ± 2.1 × 10(-6) mbar l/s and an optical loss of -0.41 ± 0.28 dB, making it suitable for use in high vacuum applications.

  17. Crack Growth Monitoring by Embedded Optical Fibre Bragg Grating Sensors: Fibre Reinforced Plastic Crack Growing Detection

    DEFF Research Database (Denmark)

    Pereira, Gilmar Ferreira; Mikkelsen, Lars Pilgaard; McGugan, Malcolm

    2015-01-01

    This article presents a novel method to asses a crack growing/damage event in fibre reinforced plastic, or adhesive using Fibre Bragg Grating (FBG) sensors embedded in a host material. Different features of the crack mechanism that induce a change in the FBG response were identified. Double...... caused by the crack, and to correlate with the FBG sensor. A Material-Sensor model was developed in order to predict the sensor output response under a crack/delamination situation, which can be used as an analysis tool for future application of this measurement technology in more complex structures....

  18. Measuring sub-picosecond optical propagation delay changes on optical fibre using photonics and radio frequency components

    Science.gov (United States)

    Julie, Roufurd P. M.; Abbott, Thomas

    2016-02-01

    To synchronise the elements of a radio interferometer array, a phase stable reference frequency from a central clock is disseminated to the different elements of array. The reference frequency is modulated onto an optical carrier and transported over optical fibre over a distance of up to 12 km. For radio interferometric efficiency, the propagation delay of the transferred reference frequency is required to be stable to less than 3 picoseconds (ps) over 20 minutes. To enable this, the optical fibre transmission line is thermally shielded to minimise length changes due to thermal expansion and contraction on the optical fibre. A test setup and procedure, that measures propagation delay changes to the required accuracy and precision, is required to verify the efficiency of the thermal shielding on the installed optical fibre. This paper describes a method using photonic and radio frequency (RF) components together with an RF vector network analyser (VNA) and post-processing to measure changes in propagation delay on the optical fibre link to sub-picosecond levels. The measurement system has been tested to a stability of < 200 femtoseconds (fs) and a resolution of < 10 fs.

  19. The role of viscoelastic properties in strain testing using microstructured polymer optical fibres (mPOF)

    International Nuclear Information System (INIS)

    Large, Maryanne C J; Moran, Joshua; Ye, Lin

    2009-01-01

    Optical fibre sensors have conventionally been made of silica. Polymers however have a much lower Young's modulus and higher elastic limit than silica, and can be incorporated into a larger range of materials. Whilst these properties make them attractive for using in mechanical sensing, using polymers also brings complexity because of their viscoelastic response. In this work, we use long period gratings (LPG) in microstructured polymer optical fibre (mPOF) as a mechanical optical sensor. The effects of stress and strain on the sensor are decoupled and analysed independently. Through experiments and modelling we show that the effect of stress (as opposed to strain), and the relaxation of stress in the optical fibre during loading have a minimal effect

  20. Brillouin light scattering from surface acoustic waves in a subwavelength-diameter optical fibre.

    Science.gov (United States)

    Beugnot, Jean-Charles; Lebrun, Sylvie; Pauliat, Gilles; Maillotte, Hervé; Laude, Vincent; Sylvestre, Thibaut

    2014-10-24

    Brillouin scattering in optical fibres is a fundamental interaction between light and sound with important implications ranging from optical sensors to slow and fast light. In usual optical fibres, light both excites and feels shear and longitudinal bulk elastic waves, giving rise to forward-guided acoustic wave Brillouin scattering and backward-stimulated Brillouin scattering. In a subwavelength-diameter optical fibre, the situation changes dramatically, as we here report with the first experimental observation of Brillouin light scattering from surface acoustic waves. These Rayleigh-type surface waves travel the wire surface at a specific velocity of 3,400 m s(-1) and backscatter the light with a Doppler shift of about 6 GHz. As these acoustic resonances are sensitive to surface defects or features, surface acoustic wave Brillouin scattering opens new opportunities for various sensing applications, but also in other domains such as microwave photonics and nonlinear plasmonics.

  1. Inverse four-wave-mixing and self-parametric amplification effect in optical fibre.

    Science.gov (United States)

    Turitsyn, Sergei K; Bednyakova, Anastasia E; Fedoruk, Mikhail P; Papernyi, Serguei B; Clements, Wallace R L

    2015-09-01

    An important group of nonlinear processes in optical fibre involves the mixing of four waves due to the intensity dependence of the refractive index. It is customary to distinguish between nonlinear effects that require external/pumping waves (cross-phase modulation and parametric processes such as four-wave mixing) and self-action of the propagating optical field (self-phase modulation and modulation instability). Here, we present a new nonlinear self-action effect, self-parametric amplification (SPA), which manifests itself as optical spectrum narrowing in normal dispersion fibre, leading to very stable propagation with a distinctive spectral distribution. The narrowing results from an inverse four-wave mixing, resembling an effective parametric amplification of the central part of the spectrum by energy transfer from the spectral tails. SPA and the observed stable nonlinear spectral propagation with random temporal waveform can find applications in optical communications and high power fibre lasers with nonlinear intra-cavity dynamics.

  2. Reliability of optical fibres and components final report of COST 246

    CERN Document Server

    Griffioen, Willem; Gadonna, Michel; Limberger, Hans; Heens, Bernard; Knuuttila, Hanna; Kurkjian, Charles; Mirza, Shehzad; Opacic, Aleksandar; Regio, Paola; Semjonov, Sergei

    1999-01-01

    Reliability of Optical Fibres and Components reports the findings of COST 246 (1993-1998) - European research initiative in the field of optical telecommunications. Experts in the materials and reliability field of optical fibres and components have contributed to this unique study programme. The results, conclusions and achievements of their work have been obtained through joint experimentation and discussion with representatives from manufacturing and research groups. Topics covered include: Lifetime estimation; Failure mechanisms; Ageing test methods; Field data and service environments for components. For the first time the reader can explore the reliability of products and examine the results and conclusions in published form. This comprehensive volume is intended to provide a deeper understanding of the reliability of optical fibres and components. The book will be extremely useful to all scientists and practitioners involved in the industry.

  3. Infra-red laser source using Tm:Ho optical fibre for potential sensor applications

    International Nuclear Information System (INIS)

    Chen, S Y; Yeo, T L; Leighton, J; Sun, T; Grattan, K T V; Lade, R; Powell, B; Foster-Turner, G; Osborne, M

    2007-01-01

    In this work, a 1600nm Er fibre laser, which demonstrates a high pumping efficiency, has been used to pump an efficient all-fibre Tm:Ho laser system using a 0.3 m length of optical fibre. A low threshold of 33 mW and a slope efficiency of 0.6% have been achieved with operation at a wavelength of ∼1870 nm. A cross-comparison has been made with the output of a device pumped by a 785 nm laser diode. The focus of the work is better and more compact sources for gas sensing in the near infra red region of the spectrum

  4. Investigation of bending loss in a single-mode optical fibre

    Indian Academy of Sciences (India)

    (glass) used for making optical fibres is about 26.211 Pa. Since radii of the core and cladding in the single-mode fibre used were 4.5 and 62.5 µm respectively, by changing θ/l, loss due to torsion stress on the core and the clad was investigated. Variation of loss against torsion stress is given in figures 10 and 11 for the core ...

  5. Numerical Simulation of Radial and Angular Distribution of γ-Ray's Energy Deposition in Scintillation Optical Fibre

    International Nuclear Information System (INIS)

    Tang Shibiao; Yin Zejie; Tang Yu; Huang Huan

    2006-01-01

    Angular and radial distributions of the energy deposition of γ-ray radiation in scintillation optical fibres are simulated and analysed using the Geant4 system. The results show a linear relation between the energy deposition and the radius of the fibres. The deposition is roughly inversely proportional to sinθ with θ the incident angle relative to the fibre axis. The results could provide corrections to the measurements of the scintillation fibres used in monitoring the γ-ray radiation

  6. France's State of the Art Distributed Optical Fibre Sensors Qualified for the Monitoring of the French Underground Repository for High Level and Intermediate Level Long Lived Radioactive Wastes.

    Science.gov (United States)

    Delepine-Lesoille, Sylvie; Girard, Sylvain; Landolt, Marcel; Bertrand, Johan; Planes, Isabelle; Boukenter, Aziz; Marin, Emmanuel; Humbert, Georges; Leparmentier, Stéphanie; Auguste, Jean-Louis; Ouerdane, Youcef

    2017-06-13

    This paper presents the state of the art distributed sensing systems, based on optical fibres, developed and qualified for the French Cigéo project, the underground repository for high level and intermediate level long-lived radioactive wastes. Four main parameters, namely strain, temperature, radiation and hydrogen concentration are currently investigated by optical fibre sensors, as well as the tolerances of selected technologies to the unique constraints of the Cigéo's severe environment. Using fluorine-doped silica optical fibre surrounded by a carbon layer and polyimide coating, it is possible to exploit its Raman, Brillouin and Rayleigh scattering signatures to achieve the distributed sensing of the temperature and the strain inside the repository cells of radioactive wastes. Regarding the dose measurement, promising solutions are proposed based on Radiation Induced Attenuation (RIA) responses of sensitive fibres such as the P-doped ones. While for hydrogen measurements, the potential of specialty optical fibres with Pd particles embedded in their silica matrix is currently studied for this gas monitoring through its impact on the fibre Brillouin signature evolution.

  7. Photocatalytic reduction of NO pollutant using an optical-fibre photoreactor at room temperature.

    Science.gov (United States)

    Yu, Yi-Hui; Su, I-Hsuan; Wu, Jeffrey C S

    2010-12-01

    Photo-assisted catalytic reduction of nitric oxide (NO) was studied over different metal-loaded TiO2 catalysts at room temperature. The activities of metal-loaded (Pt, Ag, Cu) TiO2 photocatalysts, prepared by the sol-gel method, were compared in a batch system using CH4 as the reducing agent. The Pt/TiO2 catalyst showed the highest activity for NO reduction. Thus, Pt/TiO2 was coated on optical fibres and used in a continuous-flow optical-fibre photoreactor. The optical-fibre photoreactor provides light irradiation on the photocatalyst through the optical fibre, thus improving the efficiency ofphotoreactions. Ten per cent conversion of NO was found using CH4 as the reducing agent. The NO conversions increased to 90% in the presence of water vapour and oxygen. However, most NO was oxidized to NO2. Hydrogen had superior reducing capabilities over CH4 on Pt/TiO2 photocatalyst, and the conversion of NO reached 85%. But the conversion of NO was substantially decreased to less than 10% in the presence of water vapour and oxygen. Our research proposed an alternative way to reduce NO pollutant to N2 at room temperature using an optical-fibre photoreactor, which could possibly utilize sunlight in the future.

  8. Fibre Tip Sensors for Localised Temperature Sensing Based on Rare Earth-Doped Glass Coatings

    Directory of Open Access Journals (Sweden)

    Erik P. Schartner

    2014-11-01

    Full Text Available We report the development of a point temperature sensor, based on monitoring upconversion emission from erbium:ytterbium-doped tellurite coatings on the tips of optical fibres. The dip coating technique allows multiple sensors to be fabricated simultaneously, while confining the temperature-sensitive region to a localised region on the end-face of the fibre. The strong response of the rare earth ions to changing temperature allows a resolution of 0.1–0.3 °C to be recorded over the biologically relevant range of temperatures from 23–39 °C.

  9. Simulation based optimization on automated fibre placement process

    Science.gov (United States)

    Lei, Shi

    2018-02-01

    In this paper, a software simulation (Autodesk TruPlan & TruFiber) based method is proposed to optimize the automate fibre placement (AFP) process. Different types of manufacturability analysis are introduced to predict potential defects. Advanced fibre path generation algorithms are compared with respect to geometrically different parts. Major manufacturing data have been taken into consideration prior to the tool paths generation to achieve high success rate of manufacturing.

  10. Enhanced all-optical modulation in a graphene-coated fibre with low insertion loss.

    Science.gov (United States)

    Zhang, Haojie; Healy, Noel; Shen, Li; Huang, Chung Che; Hewak, Daniel W; Peacock, Anna C

    2016-03-22

    Graphene is a highly versatile two-dimensional material platform that offers exceptional optical and electrical properties. Of these, its dynamic conductivity and low effective carrier mass are of particular interest for optoelectronic applications as they underpin the material's broadband nonlinear optical absorption and ultra-fast carrier mobility, respectively. In this paper, we utilize these phenomena to demonstrate a high-speed, in-fibre optical modulator developed on a side-polished optical fibre platform. An especially low insertion loss (fibre to a near atomically smooth surface (fibre. In order to enhance the light-matter interaction, the graphene film is coated with a high index polyvinyl butyral layer, which has the added advantage of acting as a barrier to the surrounding environment. Using this innovative approach, we have fabricated a robust and stable all-fibre device with an extinction ratio as high as 9 dB and operation bandwidth of 0.5 THz. These results represent a key step towards the integration of low-dimensional materials within standard telecoms networks.

  11. A novel inter-fibre light coupling sensor probe using plastic optical fibre for ethanol concentration monitoring at initial production rate

    Science.gov (United States)

    Memon, Sanober F.; Lewis, Elfed; Pembroke, J. Tony; Chowdhry, Bhawani S.

    2017-04-01

    A novel, low cost and highly sensitive optical fibre probe sensor for concentration measurement of ethanol solvent (C2H5OH) corresponding to bio-ethanol production rate by an algae is reported. The principle of operation of the sensor is based on inter-fibre light coupling through an evanescent field interaction to couple the light between two multimode fibres mounted parallel to each other at a minimum possible separation i.e. measurement in the broadband spectrum including visible and near infra-red. The wavelength dependency of this sensor design was also investigated by post processing analysis of real time data and hence the optimum wavelength range determined. The proposed sensor has shown significant response in the range of 0.005 - 0.1 %v/v (%volume/volume or volume concentration) which depicts the high sensitivity for monitoring very minute changes in concentration corresponding refractive index changes of the solution. Numerically, sensor has shown the sensitivity of 21945 intensity counts/%v/v or 109.7 counts per every 0.0050 %v/v.

  12. A Dual Sensor for pH and Hydrogen Peroxide Using Polymer-Coated Optical Fibre Tips.

    Science.gov (United States)

    Purdey, Malcolm S; Thompson, Jeremy G; Monro, Tanya M; Abell, Andrew D; Schartner, Erik P

    2015-12-17

    This paper demonstrates the first single optical fibre tip probe for concurrent detection of both hydrogen peroxide (H₂O₂) concentration and pH of a solution. The sensor is constructed by embedding two fluorophores: carboxyperoxyfluor-1 (CPF1) and seminaphtharhodafluor-2 (SNARF2) within a polymer matrix located on the tip of the optical fibre. The functionalised fibre probe reproducibly measures pH, and is able to accurately detect H₂O₂ over a biologically relevant concentration range. This sensor offers potential for non-invasive detection of pH and H₂O₂ in biological environments using a single optical fibre.

  13. A Dual Sensor for pH and Hydrogen Peroxide Using Polymer-Coated Optical Fibre Tips

    Directory of Open Access Journals (Sweden)

    Malcolm S. Purdey

    2015-12-01

    Full Text Available This paper demonstrates the first single optical fibre tip probe for concurrent detection of both hydrogen peroxide (H2O2 concentration and pH of a solution. The sensor is constructed by embedding two fluorophores: carboxyperoxyfluor-1 (CPF1 and seminaphtharhodafluor-2 (SNARF2 within a polymer matrix located on the tip of the optical fibre. The functionalised fibre probe reproducibly measures pH, and is able to accurately detect H2O2 over a biologically relevant concentration range. This sensor offers potential for non-invasive detection of pH and H2O2 in biological environments using a single optical fibre.

  14. Fibre optic sensors for high speed hypervelocity impact studies and low velocity drop tests

    Science.gov (United States)

    Jackson, D. A.; Cole, M. J.; Burchell, M. J.; Webb, D. J.

    2011-05-01

    The initial aim of this project was to develop a non-contact fibre optic based displacement sensor to operate in the harsh environment of a 'Light Gas Gun' (LGG), which can 'fire' small particles at velocities ranging from 1-8.4 km/s. The LGG is used extensively for research in aerospace to analyze the effects of high speed impacts on materials. Ideally the measurement should be made close to the centre of the impact to minimise corruption of the data from edge effects and survive the impact. A further requirement is that it should operate at a stand-off distance of ~ 8cm. For these reasons we chose to develop a pseudo con-focal intensity sensor, which demonstrated resolution comparable with conventional PVDF sensors combined with high survivability and low cost. A second sensor was developed based on 'Fibre Bragg Gratings' (FBG) which although requiring contact with the target the low weight and very small contact area had minimal effect on the dynamics of the target. The FBG was mounted either on the surface of the target or tangentially between a fixed location. The output signals from the FBG were interrogated in time by a new method. Measurements were made on composite and aluminium plates in the LGG and on low speed drop tests. The particle momentum for the drop tests was chosen to be similar to that of the particles used in the LGG.

  15. Carbon nanotubes for ultrafast fibre lasers

    Directory of Open Access Journals (Sweden)

    Chernysheva Maria

    2016-06-01

    Full Text Available Carbon nanotubes (CNTs possess both remarkable optical properties and high potential for integration in various photonic devices. We overview, here, recent progress in CNT applications in fibre optics putting particular emphasis on fibre lasers. We discuss fabrication and characterisation of different CNTs, development of CNT-based saturable absorbers (CNT-SA, their integration and operation in fibre laser cavities putting emphasis on state-of-the-art fibre lasers, mode locked using CNT-SA. We discuss new design concepts of high-performance ultrafast operation fibre lasers covering ytterbium (Yb, bismuth (Bi, erbium (Er, thulium (Tm and holmium (Ho-doped fibre lasers.

  16. Review of Trackside Monitoring Solutions: From Strain Gages to Optical Fibre Sensors

    Directory of Open Access Journals (Sweden)

    Georges Kouroussis

    2015-08-01

    Full Text Available A review of recent research on structural monitoring in railway industry is proposed in this paper, with a special focus on stress-based solutions. After a brief analysis of the mechanical behaviour of ballasted railway tracks, an overview of the most common monitoring techniques is presented. A special attention is paid on strain gages and accelerometers for which the accurate mounting position on the track is requisite. These types of solution are then compared to another modern approach based on the use of optical fibres. Besides, an in-depth discussion is made on the evolution of numerical models that investigate the interaction between railway vehicles and tracks. These models are used to validate experimental devices and to predict the best location(s of the sensors. It is hoped that this review article will stimulate further research activities in this continuously expanding field.

  17. Review of Trackside Monitoring Solutions: From Strain Gages to Optical Fibre Sensors.

    Science.gov (United States)

    Kouroussis, Georges; Caucheteur, Christophe; Kinet, Damien; Alexandrou, Georgios; Verlinden, Olivier; Moeyaert, Véronique

    2015-08-14

    A review of recent research on structural monitoring in railway industry is proposed in this paper, with a special focus on stress-based solutions. After a brief analysis of the mechanical behaviour of ballasted railway tracks, an overview of the most common monitoring techniques is presented. A special attention is paid on strain gages and accelerometers for which the accurate mounting position on the track is requisite. These types of solution are then compared to another modern approach based on the use of optical fibres. Besides, an in-depth discussion is made on the evolution of numerical models that investigate the interaction between railway vehicles and tracks. These models are used to validate experimental devices and to predict the best location(s) of the sensors. It is hoped that this review article will stimulate further research activities in this continuously expanding field.

  18. Optical coherence tomography assisted retinal nerve fibre layer thickness profile in high myopia.

    Science.gov (United States)

    Malakar, Mousumi; Askari, Syed Nasir; Ashraf, Humayun; Waris, Abdul; Ahuja, Anupam; Asghar, Adil

    2015-02-01

    To evaluate the association of high myopia with retinal nerve fibre layer (RNFL) thickness by Fourier domain optical coherence tomography (FD OCT). Fifty highly myopic eyes (25 patients) and forty emmetropic eyes (20 Normal subject) were randomly selected after excluding concomitant ophthalmic disorder and RNFL thickness measured using the Fourier domain optical coherence tomography (FD OCT). The overall mean RNFL thickness in the myopic groups and control were 87.89 μm and 111.64 μm respectively. The mean retinal nerve fibre thickness was significantly less in myopic eyes as compared to control group (p =0.0001). Retinal nerve fibre layer thickness shows topographic double hump pattern in both the groups (myopes and emmetropes). Retinal nerve fibre thickness was significantly less in myopic eyes as compared to emmetropic eyes. The retinal nerve fibre layer thinning in high myopes may be confused with open angle glaucoma, a disease also prevalent in high myopes. There is therefore a need to have retinal nerve fibre layer thickness normogram for high myopes of a given population group to avoid wrong interpretation.

  19. Addressing the needs of the telecoms industry for optical fibre communication in Africa

    Science.gov (United States)

    Leitch, Andrew W. R.; Conibear, Ann B.

    2005-10-01

    We report on a successful partnership between the Department of Physics at the Nelson Mandela Metropolitan University (NMMU) and Telkom, South Africa's national telecommunications company, to train physics students in the important fields related to optical fibre technology. The partnership, which began in 2001 and forms part of Telkom's Centre of Excellence program in South Africa, is currently being extended to other countries in Africa. The training being conducted in the Physics Department has as one of its main goals an increased understanding of polarisation mode dispersion (PMD), an effect that will ultimately limit the transmission speeds through optical fibre.

  20. Design of a fibre-optic disc accelerometer: theory and experiment

    Science.gov (United States)

    Wang, Yongjie; Xiao, Hao; Zhang, Songwei; Li, Fang; Liu, Yuliang

    2007-06-01

    Mechanical principles of fibre-optic disc accelerometers (FODA) different from those assumed in previous calculation methods are presented. An FODA with a high sensitivity of 82 rad/g and a resonance frequency of 360 Hz is designed and tested. In this system, the minimum measurable demodulation phase of the phase-generated carrier (PGC) is 10-5 rad, and the minimum acceleration reaches 120 ng theoretically. This kind of FODA, with its high responsivity, all-optic-fibre configuration, small size, light weight and stiff shell housing, ensures effective performance in practice.

  1. Implementing optical fibres for the structural health monitoring of composite patch repaired structures

    DEFF Research Database (Denmark)

    Karatzas, Vasileios; Kotsidis, Elias A.; Tsouvalis, Nicholas G.

    2017-01-01

    . This work deals with the use of Fabry Perot optical fibres and strain gages at suitable positions in such a repair. To this end a patch repaired notched steel plate has been tested in tension, opting to gain insight on the mechanisms which govern the failure. In order to investigate how these mechanisms...... are reflected to the recorded strain measurements, finite element models have been generated. Results indicate that composite patch repairing drastically increased the load bearing capacity of the plates and that optical fibres constitute an appealing health monitoring system for such applications, being able...

  2. Optical properties of bismuth-doped silica fibres in the temperature range 300 - 1500 K

    Energy Technology Data Exchange (ETDEWEB)

    Dvoretskii, D A; Bufetov, Igor' A; Vel' miskin, V V; Zlenko, Alexander S; Khopin, V F; Semjonov, S L; Guryanov, Aleksei N; Denisov, L K; Dianov, Evgenii M

    2012-09-30

    The visible and near-IR absorption and luminescence bands of bismuth-doped silica and germanosilicate fibres have been measured for the first time as a function of temperature. The temperature-dependent IR luminescence lifetime of a bismuth-related active centre associated with silicon in the germanosilicate fibre has been determined. The Bi{sup 3+} profile across the silica fibre preform is shown to differ markedly from the distribution of IR-emitting bismuth centres associated with silicon. The present results strongly suggest that the IR-emitting bismuth centre comprises a lowvalence bismuth ion and an oxygen-deficient glass network defect. (optical fibres, lasers and amplifiers. properties and applications)

  3. Statistical parity-time-symmetric lasing in an optical fibre network.

    Science.gov (United States)

    Jahromi, Ali K; Hassan, Absar U; Christodoulides, Demetrios N; Abouraddy, Ayman F

    2017-11-07

    Parity-time (PT)-symmetry in optics is a condition whereby the real and imaginary parts of the refractive index across a photonic structure are deliberately balanced. This balance can lead to interesting optical phenomena, such as unidirectional invisibility, loss-induced lasing, single-mode lasing from multimode resonators, and non-reciprocal effects in conjunction with nonlinearities. Because PT-symmetry has been thought of as fragile, experimental realisations to date have been usually restricted to on-chip micro-devices. Here, we demonstrate that certain features of PT-symmetry are sufficiently robust to survive the statistical fluctuations associated with a macroscopic optical cavity. We examine the lasing dynamics in optical fibre-based coupled cavities more than a kilometre in length with balanced gain and loss. Although fluctuations can detune the cavity by more than the free spectral range, the behaviour of the lasing threshold and the laser power is that expected from a PT-stable system. Furthermore, we observe a statistical symmetry breaking upon varying the cavity loss.

  4. Demonstration of Raman-based, dispersion-managed VCSEL technology for fibre-to-the-hut application

    Science.gov (United States)

    Rotich Kipnoo, E. K.; Kiboi Boiyo, D.; Isoe, G. M.; Chabata, T. V.; Gamatham, R. R. G.; Leitch, A. W. R.; Gibbon, T. B.

    2017-03-01

    For the first time, we experimentally investigate the use of vertical cavity surface emitting lasers (VCSELs) in the fibre-to-the-home (FTTH) flavour for Africa, known as fibre-to-the-hut. Fibre-to-the-hut is a VCSEL based passive optical network technology designed and optimized for African continent. VCSELs have attracted attention in optical communication due to its vast advantages; low power consumption, relatively cheap costs among others. A 4.25 Gb/s uncooled VCSEL is used in a dispersion managed, Raman assisted network achieving beyond 100 km of error free transmission suited for FTTHut scenario. Energy-efficient high performance VCSEL is modulated using a 27-1 PRBS pattern and the signal transmitted on a G.655 fibre utilizing the minimum attenuation window.

  5. pH sensing through a single optical fibre using SERS and CMOS SPAD line arrays.

    Science.gov (United States)

    Ehrlich, K; Kufcsák, A; McAughtrie, S; Fleming, H; Krstajic, N; Campbell, C J; Henderson, R K; Dhaliwal, K; Thomson, R R; Tanner, M G

    2017-12-11

    Full exploitation of fibre Raman probes has been limited by the obstruction of weak Raman signals by background fluorescence of the sample and the intrinsic Raman signal of the delivery fibre. Here we utilised functionalised gold nanoshells (NS) to take advantage of the surface-enhanced Raman spectroscopy (SERS) effect to enhance the pH responsive spectrum of 4-mercaptobenzoic acid (MBA). However, the fibre background is still dominant. Using the photon arrival time-resolving capability of a CMOS single-photon avalanche diode (SPAD) based line sensor, we recover the SERS spectrum without a fibre background in a 10 s measurement. In this manner, pH sensing through a multimode fibre at a low excitation power that is safe for future in vivo applications, with short acquisition times (10 or 60 s), is demonstrated. A measurement precision of ± 0.07 pH units is thus achieved.

  6. Fibre optics cabling design for LHC detectors upgrade using variable radiation induced attenuation model

    CERN Document Server

    Shoaie, Mohammad Amin; Machado, Simao; Ricci, Daniel

    2018-01-01

    Foreseen upgrades over the next decades enable LHC to operate at a higher luminosity (HL-LHC). Accordingly, the optical links designed to transmit particle collision data need to be hardened against increased radiation level, allowing for a reliable communication. In this paper we study the fibre cabling design of a link between the transceiver optical front-end and the data control room. The radiation penalty calculation takes temperature drop down to ‒30°C into account. The proposed solution concatenates radiation-resistance and conventional fibres using multi-fibre interconnections. The end-to-end link loss during HL-LHC lifetime is estimated strictly less than 3.5 dB complying with predefined margin.

  7. Dispersion-engineered and highly-nonlinear microstructured polymer optical fibres

    DEFF Research Database (Denmark)

    Frosz, Michael Henoch; Nielsen, Kristian; Hlubina, Petr

    2009-01-01

    We demonstrate dispersion-engineering of microstructured polymer optical fibres (mPOFs) made of poly(methyl methacrylate) (PMMA). A significant shift of the total dispersion from the material dispersion is confirmed through measurement of the mPOF dispersion using white-light spectral interferome...

  8. A simple optical fibre-linked remote control system for multiple devices

    Indian Academy of Sciences (India)

    MS received 11 June 2003. Abstract. We report on the development of a simple control system which can handle multiple devices through an optical fibre data link. The devices are controlled using a set of DACs through serial data communication via a serial port of a PC. Serial data from the PC get converted to parallel ...

  9. Calibration of an experimental six component wind tunnel block balance using optical fibre sensors

    CSIR Research Space (South Africa)

    de Ponte, JD

    2016-05-01

    Full Text Available Symposium on Strain-Gauge Balances, Mianyang, Sichuan China, 16-19 May 2016 Calibration of an Experimental Six Component Wind Tunnel Block Balance Using Optical Fibre Sensors J.D. de Ponte1, F.F. Pieterse2 1, 2University of Johannesburg, Auckland...

  10. Bubble shape and orientation determination with a four-point optical fibre probe

    NARCIS (Netherlands)

    Guet, S.; Luther, S.; Ooms, G.

    2003-01-01

    We propose a new method to estimate the aspect ratio and orientation of bubbles by using their time series obtained with a four-point optical-fibre probe. The feasibility and accuracy of the method was first analysed by using synthetic bubble–probe interaction data and single bubble experiments in

  11. Measuring the Dispersion Curve of a PMMA-Fibre Optic Cable Using a Dye Laser

    Science.gov (United States)

    Zorba, Serkan; Farah, Constantine; Pant, Ravi

    2010-01-01

    An advanced undergraduate laboratory experiment is outlined which uses a dye laser to map out the chromatic dispersion curve of a polymethyl methacrylate (PMMA) optical fibre. Seven different wavelengths across the visible spectrum are employed using five different dyes. The light pulse is split into two pulses, one to a nearby photodetector and…

  12. On the jitter of mode-locked pulses introduced by an optical fibre

    NARCIS (Netherlands)

    Mols, R.F.X.A.M.; Mols, R.F.X.A.M.; Ernst, G.J.

    1993-01-01

    Measurements on the jitter of mode-locked pulses of a Nd:YLF laser after travelling through an optical fibre are presented. For low powers self phase modulation occurs which leaves the jitter unaltered. For powers higher than the threshold of stimulated Raman scattering the jitter increases due to

  13. Repetitive Inductions of Bioluminescence of Pseudomonas putida TVA8 Immobilized by Adsorption on Optical Fibre.

    Czech Academy of Sciences Publication Activity Database

    Zajíc, J.; Bittner, M.; Brányik, T.; Solovyev, Andrey; Šabata, Stanislav; Kuncová, Gabriela; Pospíšilová, M.

    2016-01-01

    Roč. 70, č. 7 (2016), s. 877-887 ISSN 0366-6352 Institutional support: RVO:67985858 Keywords : whole-cell biosensor * bioluminiscent bioreporter * optical fibre sensor Subject RIV: CC - Organic Chemistry Impact factor: 1.258, year: 2016

  14. Multimode laser emission from dye-doped hollow polymer optical fibre

    Indian Academy of Sciences (India)

    2014-02-09

    Feb 9, 2014 ... doped fibre is a highly efficient medium for laser source with narrow pulse width and wide tunable range as well as for optical amplifier with high gain, high power conversion and broad spectral bandwidth [6]. In this paper we report the fabrication and observation of lasing modes from hollow cylindrical ...

  15. 3-D printed sensing patches with embedded polymer optical fibre Bragg gratings

    DEFF Research Database (Denmark)

    Zubel, Michal G.; Sugden, Kate; Saez-Rodriguez, D.

    2016-01-01

    The first demonstration of a polymer optical fibre Bragg grating (POFBG) embedded in a 3-D printed structure is reported. Its cyclic strain performance and temperature characteristics are examined and discussed. The sensing patch has a repeatable strain sensitivity of 0.38 pm/mu epsilon. Its...

  16. Manufacturing a Micro-model with Integrated Fibre Optic Pressure Sensors

    NARCIS (Netherlands)

    Zarikos, I.|info:eu-repo/dai/nl/413577473; Hassanizadeh, S.M.|info:eu-repo/dai/nl/074974424; van Oosterhout, L.M.|info:eu-repo/dai/nl/413490475; van Oordt, Wim

    The measurement of fluid pressure inside pores is a major challenge in experimental studies of two-phase flow in porous media. In this paper, we describe the manufacturing procedure of a micro-model with integrated fibre optic pressure sensors. They have a circular measurement window with a diameter

  17. New radiation-induced effects in optical fibres feasible for dosimetry

    International Nuclear Information System (INIS)

    Tomashuk, A.L.; Golant, K.M.; Dianov, E.M.; Nikolin, I.V.; Zakharkin, I.I.; Stepanov, V.A.

    1999-01-01

    Three new radiation-induced effects in silica optical fibres suitable for dosimetry are proposed: 1) in fibres with a high-OH cladding and a low-OH core, ionizing radiation disrupts the O-H bonds to let hydrogen diffuse into the core. This results in an increase in the OH-group absorption band amplitude, 2) the polymers used to coat optical fibres consist of hydrogen to the extent of about 50 %. Energetic neutrons produce recoil protons in the fibre coating, which can ''stick'' in the core, turn into hydrogen, and enter the glass network in the form of OH-group, and 3) in N-doped silica fibres irradiated with thermal neutrons, the following reaction 7 N 14 ( 0 n 1 , 1 p 1 ) 6 C 14 occurs and produces protons with energy 620 keV. With this energy, propagation length of protons in silica is 7 μm which means that the escape of protons from a 50 μm core is very weak. In fact all 3 effects lead to the irreversible increase in the OH-group absorption bands, which is proportional to the absorbed dose. With the help of these effects, temperature and dose-rate independent measurements of high doses become possible

  18. Erbium Doped Fibre Lasers up t 1618 nm for Optical Communication beyond the L-band

    DEFF Research Database (Denmark)

    Kristensen, Martin; Varming, Poul; Jensen, Jesper Bo

    1999-01-01

    lasers are difficult to get beyond the L-band. Therefore no transmission systems have ever been made in this wavelength region despite that low loss transmission should still be possible in standard fibres. With the increasing demand for optical bandwidth it will soon be essential to use the entire low...... loss region for optical fibres. Communication beyond the L-band will therefore probably be necessary within the next 1-3 years.Through careful optimisation of the DFB fibre laser cavity and by using a high gain fibre we have demonstrated stable single-mode lasers up to 1618nm. We have performed 10Gbit......Up to a few months ago it was expected theoretically that erbium doped DFB fibre lasers could not be made to operate at wavelengths above the L-band (1570nm-1610nm). This is due to the combination of very low gain and problems with two-photon absorption in the erbium. In addition semiconductor DFB...

  19. A robust fibre laser system for electro-optic electron bunch profile measurements at FLASH

    International Nuclear Information System (INIS)

    Wissmann, Laurens-Georg

    2012-08-01

    For the electro-optic measurement of electron bunch profiles at FLASH a robust ytterbium doped fibre laser (YDFL) system has been developed consisting of a laser oscillator and a two-staged amplifier. The oscillator is designed to meet the specifications of high reliability and low noise operation. The amplifier makes use of tailored nonlinearity to enhance the spectral bandwidth of the output laser pulses. Active repetition rate control enables sub-picosecond synchronisation of the laser to the accelerator reference RF. Using a two-stage gating scheme the output pulse train repetition rate is adopted to the accelerator repetition rate. An experimental site used for electro-optic electron bunch diagnostics has been redesigned to support single-shot bunch profile measurements based on spectral decoding. An existing bunch profile monitor with a similar laser system was upgraded and electro-optic bunch profile measurements were conducted, allowing for a comparison with measurements done with other longitudinal electron bunch diagnostics and with former measurements.

  20. A robust fibre laser system for electro-optic electron bunch profile measurements at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Wissmann, Laurens-Georg

    2012-08-15

    For the electro-optic measurement of electron bunch profiles at FLASH a robust ytterbium doped fibre laser (YDFL) system has been developed consisting of a laser oscillator and a two-staged amplifier. The oscillator is designed to meet the specifications of high reliability and low noise operation. The amplifier makes use of tailored nonlinearity to enhance the spectral bandwidth of the output laser pulses. Active repetition rate control enables sub-picosecond synchronisation of the laser to the accelerator reference RF. Using a two-stage gating scheme the output pulse train repetition rate is adopted to the accelerator repetition rate. An experimental site used for electro-optic electron bunch diagnostics has been redesigned to support single-shot bunch profile measurements based on spectral decoding. An existing bunch profile monitor with a similar laser system was upgraded and electro-optic bunch profile measurements were conducted, allowing for a comparison with measurements done with other longitudinal electron bunch diagnostics and with former measurements.

  1. Fibre laser based broadband THz imaging systems

    DEFF Research Database (Denmark)

    Eichhorn, Finn

    imaging techniques. This thesis exhibits that fiber technology can improve the robustness and the flexibility of terahertz imaging systems both by the use of fiber-optic light sources and the employment of optical fibers as light distribution medium. The main focus is placed on multi-element terahertz...

  2. Curved adjustable fibre-optic diode laser in microscopic cholesteatoma surgery: description of use and review of the relevant literature.

    Science.gov (United States)

    McCaffer, C J; Pabla, L; Watson, C

    2018-03-08

    The use of lasers in cholesteatoma surgery is common and well accepted. The most commonly used laser fibres are straight and non-adjustable; these have several limitations. This paper describes the use of an alternative laser fibre. This 'How I Do It' paper describes and illustrates the use of an alternative curved adjustable fibre-optic diode laser in microscopic cholesteatoma surgery. The curved, adjustable laser fibre allows accurate and atraumatic disease removal when the use of a straight laser fibre may be less effective or accurate. It reduces potential damage to delicate structures without the need for extra drilling or bone removal. It is suggested that the curved adjustable laser fibre is superior to the traditional straight fibre for cholesteatoma surgery.

  3. Polarization contrast in reflection near-field optical microscopy with uncoated fibre tips

    DEFF Research Database (Denmark)

    Bozhevolnyi, Sergey I.; Langbein, Wolfgang; Hvam, Jørn Märcher

    1999-01-01

    Using cross-hatched, patterned semiconductor surfaces and round 20-nm-thick gold pads on semiconductor wafers, we investigate the imaging characteristics of a reflection near-field optical microscope with an uncoated fibre tip for different polarization configurations and light wavelengths....... Is is shown that cross-polarized detection allows one to effectively suppress far-field components in the detected signal and to realise imaging of optical contrast on the sub-wavelength scale. The sensitivity window of our microscope, i.e. the scale on which near-field optical images represent mainly optical...

  4. Fabrication of a side aligned optical fibre interferometer by focused ion beam machining

    International Nuclear Information System (INIS)

    Sun, J; Miller, M K; Ritchie, J M; Luo, X; Li, J; Maier, R R J; Hand, D P; MacPherson, W N

    2013-01-01

    Focused ion beam (FIB) machining is a promising technique for the fabrication of micro-optical components with high quality surface finishes. In this work, a prototype of a side aligned optical fibre interferometer was successfully fabricated by the three-dimensional deterministic FIB machining technique. A highly accurate 45° reflective mirror with surface roughness (Ra) of 10 nm has been successfully fabricated at the centre of the fibre to direct the core guided light to the side of the fibre. A surface topography simulation method was developed to simulate the ion beam polishing process. According to the simulation result, a 0.5° offset on the ion beam polishing direction is necessary to maintain the machining accuracy. In the fabrication process, it was also found that for structures requiring a high aspect ratio the existence of an open edge can mitigate against the material redeposition on the sidewalls and therefore increase the overall material removal rate. The fibre has been tested optically and the interference signals have been successfully observed, demonstrating the alignment accuracy of the fabrication method. (paper)

  5. High stress monitoring of prestressing tendons in nuclear concrete vessels using fibre-optic sensors

    Energy Technology Data Exchange (ETDEWEB)

    Perry, M., E-mail: marcus.perry@strath.ac.uk [Institute for Energy and Environment, University of Strathclyde, 204 George Street, Glasgow G1 1XW (United Kingdom); Yan, Z.; Sun, Z.; Zhang, L. [Aston Institute of Photonic Technologies, Aston University, Birmingham B4 7ET (United Kingdom); Niewczas, P. [Institute for Energy and Environment, University of Strathclyde, 204 George Street, Glasgow G1 1XW (United Kingdom); Johnston, M. [Civil Design Group, EDF Energy, Nuclear Generation, East Kilbride G74 5PG (United Kingdom)

    2014-03-15

    Highlights: • We weld radiation-resistant optical fibre strain sensors to steel prestressing tendons. • We prove the sensors can survive 1300 MPa stress (80% of steel's tensile strength). • Mechanical relaxation of sensors is characterised under 1300 MPa stress over 10 h. • Strain transfer between tendon and sensor remains at 69% after relaxation. • Sensors can withstand and measure deflection of tendon around a 4.5 m bend radius. - Abstract: Maintaining the structural health of prestressed concrete nuclear containments is a key element in ensuring nuclear reactors are capable of meeting their safety requirements. This paper discusses the attachment, fabrication and characterisation of optical fibre strain sensors suitable for the prestress monitoring of irradiated steel prestressing tendons. The all-metal fabrication and welding process allowed the instrumented strand to simultaneously monitor and apply stresses up to 1300 MPa (80% of steel's ultimate tensile strength). There were no adverse effects to the strand's mechanical properties or integrity. After sensor relaxation through cyclic stress treatment, strain transfer between the optical fibre sensors and the strand remained at 69%. The fibre strain sensors could also withstand the non-axial forces induced as the strand was deflected around a 4.5 m bend radius. Further development of this technology has the potential to augment current prestress monitoring practices, allowing distributed measurements of short- and long-term prestress losses in nuclear prestressed-concrete vessels.

  6. Real-time measurements of spontaneous breathers and rogue wave events in optical fibre modulation instability.

    Science.gov (United States)

    Närhi, Mikko; Wetzel, Benjamin; Billet, Cyril; Toenger, Shanti; Sylvestre, Thibaut; Merolla, Jean-Marc; Morandotti, Roberto; Dias, Frederic; Genty, Goëry; Dudley, John M

    2016-12-19

    Modulation instability is a fundamental process of nonlinear science, leading to the unstable breakup of a constant amplitude solution of a physical system. There has been particular interest in studying modulation instability in the cubic nonlinear Schrödinger equation, a generic model for a host of nonlinear systems including superfluids, fibre optics, plasmas and Bose-Einstein condensates. Modulation instability is also a significant area of study in the context of understanding the emergence of high amplitude events that satisfy rogue wave statistical criteria. Here, exploiting advances in ultrafast optical metrology, we perform real-time measurements in an optical fibre system of the unstable breakup of a continuous wave field, simultaneously characterizing emergent modulation instability breather pulses and their associated statistics. Our results allow quantitative comparison between experiment, modelling and theory, and are expected to open new perspectives on studies of instability dynamics in physics.

  7. Retinal nerve fibre layer thickness measurements by optical coherence tomography in patients with sleep apnoea syndrome.

    Science.gov (United States)

    Sagiv, Oded; Fishelson-Arev, Tagil; Buckman, Gila; Mathalone, Nurit; Wolfson, Julia; Segev, Eitan; Peled, Ron; Lavi, Idit; Geyer, Orna

    2014-03-01

    The study aims to investigate whether retinal nerve fibre layer (RNFL) abnormalities can be detected in patients with obstructive sleep apnoea/hypopnoea syndrome with normally appearing optic disc. This is an observational case-control study. One hundred and eight consecutive patients with moderate or severe obstructive sleep apnoea/hypopnoea syndrome (OSAHS) as determined by overnight polysomnography and normal looking discs and 108 age-matched healthy controls were included in the study. All patients underwent RNFL examinations by optical coherence tomography using fast retinal nerve fibre layer thickness scan. The main outcome measure was RNFL thickness. Multivariate regression analysis results showed that the RNFL was thinner for a patient with OSAHS than that of a normal control in the average by 4.20 μm (P optic nerves will eventually lead to glaucoma. © 2013 Royal Australian and New Zealand College of Ophthalmologists.

  8. Intensifying the response of distributed optical fibre sensors using 2D and 3D image restoration.

    Science.gov (United States)

    Soto, Marcelo A; Ramírez, Jaime A; Thévenaz, Luc

    2016-03-01

    Distributed optical fibre sensors possess the unique capability of measuring the spatial and temporal map of environmental quantities that can be of great interest for several field applications. Although existing methods for performance enhancement have enabled important progresses in the field, they do not take full advantage of all information present in the measured data, still giving room for substantial improvement over the state-of-the-art. Here we propose and experimentally demonstrate an approach for performance enhancement that exploits the high level of similitude and redundancy contained on the multidimensional information measured by distributed fibre sensors. Exploiting conventional image and video processing, an unprecedented boost in signal-to-noise ratio and measurement contrast is experimentally demonstrated. The method can be applied to any white-noise-limited distributed fibre sensor and can remarkably provide a 100-fold improvement in the sensor performance with no hardware modification.

  9. Optical fibre demultiplexers for systems of the information transfer

    Directory of Open Access Journals (Sweden)

    Dement’ev S. G.

    2010-03-01

    Full Text Available The manufacturing techniques of fused single-mode multiplexer/demultiplexer with high coefficient of optical isolation (up to 60 dB and low losses (less than 0,4 dB are presented. Optical characteristics of the made samples are investigated. Results of the tests in temperature range –60 to +85°C are given.

  10. Suppression of Brillouin scattering in fibre-optical parametric amplifier by applying temperature control and phase modulation

    DEFF Research Database (Denmark)

    Lorenzen, Michael Rodas; Noordegraaf, Danny; Nielsen, Carsten Vandel

    2009-01-01

    An increased gain in a fibre-optical parametric amplifier through suppression of stimulated Brillouin scattering is demonstrated by applying a temperature distribution along the fibre for a fixed phase modulation of the pump. The temperature distribution slightly impacts the gain spectrum....

  11. CW-OSL measurement protocols using optical fibre Al2O3:C dosemeters

    DEFF Research Database (Denmark)

    Edmund, J.M.; Andersen, C.E.; Marckmann, C.J.

    2006-01-01

    A new system for in vivo dosimetry during radiotherapy has been introduced. Luminescence signals from a small crystal of carbon-doped aluminium oxide (Al2O3:C) are transmitted through an optical fibre cable to an instrument that contains optical filters, a photomultiplier tube and a green (532 nm......) laser. The prime output is continuous wave optically stimulated luminescence (CW-OSL) used for the measurement of the integrated dose. We demonstrate a measurement protocol with high reproducibility and improved linearity, which is suitable for clinical dosimetry. A crystal-specific minimum pre...

  12. Correlation of structural retinal nerve fibre layer parameters and functional measures using Heidelberg Retinal Tomography and Spectralis spectral domain optical coherence tomography at different levels of glaucoma severity.

    Science.gov (United States)

    Leaney, John; Healey, Paul R; Lee, Martin; Graham, Stuart L

    2012-11-01

    To compare the structure/function relationship in glaucoma cases at different levels of severity, and with different disc sizes, between the Heidelberg Retinal Tomography and Spectralis spectral domain optical coherence tomography. Retrospective study of glaucoma patients attending a Sydney-based private practice. 169 eyes of 169 patients with a clinical diagnosis of glaucoma. Patients were divided on visual field criteria into early (mean deviation > -4 dB), moderate (-4 dB fibre layer thickness sectoral measurement were calculated. Correlation, as measured by Spearman's rho, between retinal nerve fibre layer measurements and mean threshold scores. Comparison of correlation strengths between the two scanning modalities with analysis of the effect of disease severity and disc size. Both imaging techniques showed only moderate correlations at best. Spectral domain optical coherence tomography (global retinal nerve fibre layer Spearman's rho = 0.670, P fibre layer (Spearman's rho = 0.421, P optical coherence tomography retinal nerve fibre layer measurements demonstrated closer correlations to visual field threshold reductions using a structure/function model in varying stages of glaucoma. © 2012 The Authors. Clinical and Experimental Ophthalmology © 2012 Royal Australian and New Zealand College of Ophthalmologists.

  13. Heuristic approach to the passive optical network with fibre duct ...

    African Journals Online (AJOL)

    PON) planning problem necessitates the search for a subset of deployed facilities (splitters) and their allocated demand points (optical network units) to minimise the overall deployment cost. A mixed integer linear programming formulation ...

  14. TAPERED OPTICAL FIBRES FOR LOCAL pH DETECTION

    Czech Academy of Sciences Publication Activity Database

    Martan, Tomáš; Pospíšilová, Marie; Aubrecht, Jan; Mrázek, Jan; Podrazký, Ondřej; Kašík, Ivan; Matějec, Vlastimil

    2010-01-01

    Roč. 206, č. 1 (2010), 0120171-0120172 ISSN 1742-6588. [8th International Workshop on Information Optics (WIO' 09). Paris, 20.07.2009-24.07.2009] R&D Projects: GA ČR(CZ) GP102/08/P639 Institutional research plan: CEZ:AV0Z20670512 Keywords : optical planar sensor * fluorescence * pH Subject RIV: JB - Sensors, Measurment, Regulation

  15. The Use of Bragg Gratings in the Core and Cladding of Optical Fibres for Accurate Strain SensingThe Use of Bragg Gratings in the Core and Cladding of Optical Fibres for Accurate Strain Sensing

    Directory of Open Access Journals (Sweden)

    Ian G. PLATT

    2008-04-01

    Full Text Available Optical Fibre Sensors (OFS have many advantages over others type of sensors for measuring strain or micro-displacement. This paper introduces a new configuration of Bragg gratings within an optical fibre to improve strain measurement resolution and accuracy. We describe the geometry, together with the research direction currently being undertaken to produce a commercially viable micro-displacement sensor suitable for a number of architectural and engineering application.

  16. Laser–fibre vibrometry at 1550 nm

    International Nuclear Information System (INIS)

    Waz, A T; Kaczmarek, P R; Abramski, K M

    2009-01-01

    This paper presents new solutions for laser vibrometry, which are based on fibre vibrometry in the third telecommunication window. The scattered laser beam from a vibrating object is guided by a fibre collimator and coherently detected through heterodyning it with an acousto-optical frequency-shifted reference beam. The concept of measuring vibration parameters from many points of the vibrating object has been inspired by wavelength division multiplexing (WDM) in fibre telecommunications. The N-independent WDM separated 15XX nm fibre-coupled laser diodes (used for optical fibre telecommunications) form a system of sources for multipoint vibration measurement according to the rule 'one wavelength–one point'

  17. Effects of γ and neutron irradiation on the optical absorption of pure silica core single-mode optical fibres from Nufern

    International Nuclear Information System (INIS)

    Calderon, A.; Martinez-Rivero, C.; Matorras, F.; Rodrigo, T.; Sobron, M.; Vila, I.; Virto, A.L.; Alberdi, J.; Arce, P.; Barcala, J.M.; Calvo, E.; Ferrando, A.; Josa, M.I.; Luque, J.M.; Molinero, A.; Navarrete, J.; Oller, J.C.; Valdivieso, P.; Yuste, C.; Fenyvesi, A.; Molnar, J.

    2006-01-01

    A measurement of the optical absorption, induced by photon irradiation up to a dose of 0.9 MGy, in Nufern silica core single-mode optical fibres is presented. In addition, the fibres were irradiated with neutrons, up to a total fluence of 2x10 14 cm -2 and the induced optical absorption was evaluated for four different wavelengths: 630, 670, 681 and 785 nm

  18. Influence of the stem effect on radioluminescence signals from optical fibre Al2O3:C dosemeters

    DEFF Research Database (Denmark)

    Marckmann, C.J.; Aznar, M.C.; Andersen, C.E.

    2006-01-01

    This paper analyses the influence of the Cerenkov radiation and other noise sources, the so-called stem effect, on radioluminescence (RL) signals generated in optical fibre Al2O3:C dosemeters used in medical dosimetry. The optical fibre dosemeter consists of a sensitive Al2O3:C crystal coupled...... to an optical fibre cable that carries the RL and optically stimulated luminescence (OSL) signals generated in the Al2O3:C crystal. During irradiation of the dosemeter, the real-time dose rate can be determined from the RL signal and after irradiation the total dose absorbed is determined from the OSL signal...... stimulated using a focused green solid-state laser. In particular, the components of the stem effect generated in the fibres were analysed to determine their impact on the RL signal....

  19. Polymer Optical Fibre Bragg Grating Humidity Sensor at 100ºC

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Fasano, Andrea; Markos, Christos

    2016-01-01

    We have demonstrated a polymer optical fibre Bragg grating humidity sensor that can be operated up to 100ºC. The sensor has been fabricated from a polycarbonate (PC) microstructured polymer optical fibre Bragg grating (mPOFBG). PC mPOFBG gave a relative humidity (RH) sensitivity of 6.95±0.83 pm....../% RH in the range 10-90% RH at 100ºC and a temperature sensitivity of 25.94±0.47 pm/ºC in the range 20 - 100 ºC at 90% RH. Despite PC mPOFBGs shows smaller humidity sensitivity compared to PMMA mPOFBGs, they can be used to sense humidity beyond the operating temperature limit of PMMA mPOFBGs....

  20. Multi-parameter measurements using optical fibre long period gratings for indoor air quality monitoring

    Science.gov (United States)

    Hromadka, J.; Korposh, S.; Partridge, M. C.; James, S.; Davis, F.; Crump, D.; Lee, S.-W.; Tatam, R. P.

    2017-04-01

    An array of three long period gratings (LPGs) fabricated in a single optical fibre and multiplexed in the wavelength domain was used to measure simultaneously temperature, relative humidity (RH) and volatile organic compounds (VOCs). Each LPG sensor was designed to optimize its response to a desired measurand. The LPGs were fabricated with periods such that they operated at or near the phase matching turning point. The sensors were calibrated in the laboratory and the simultaneous measurement of the key indoor air quality parameters was undertaken in laboratory and office environments. It was demonstrated successfully that the data produced by the LPG sensor array under real conditions was in a good agreement with that produced by commercially available sensors. Further, the potential application of fibre optic sensors for VOCs detection at high levels has been demonstrated.

  1. High-resolution optical spectroscopy using multimode interference in a compact tapered fibre.

    Science.gov (United States)

    Wan, Noel H; Meng, Fan; Schröder, Tim; Shiue, Ren-Jye; Chen, Edward H; Englund, Dirk

    2015-07-23

    Optical spectroscopy is a fundamental tool in numerous areas of science and technology. Much effort has focused on miniaturizing spectrometers, but thus far at the cost of spectral resolution and broad operating range. Here we describe a compact spectrometer that achieves both high spectral resolution and broad bandwidth. The device relies on imaging multimode interference from leaky modes along a multimode tapered optical fibre, resulting in spectrally distinguishable spatial patterns over a wide range of wavelengths from 500 to 1,600 nm. This tapered fibre multimode interference spectrometer achieves a spectral resolution down to 40 pm in the visible spectrum and 10 pm in the near-infrared spectrum (corresponding to resolving powers of 10(4)-10(5)). Multimode interference spectroscopy is suitable in a variety of device geometries, including planar waveguides in a broad range of transparent materials.

  2. A Proposal to Develop and Test a Fibre-Optic Coupled Solar Thermal Propulsion System for Microsatellites

    Science.gov (United States)

    2006-03-01

    b) Figure 2.2: (a) Parabolic solar cooker . (b) Fresnel solar cooker Fibre Optic Solar Thermal Propulsion Demonstration Technology 8 external...Proposal to Develop and Test a Fibre-Optic Coupled Solar Thermal Propulsion System for Microsatellites 5c. PROGRAM ELEMENT NUMBER 5d. PROJECT...report results from a contract tasking University of Surrey. Solar Thermal Propulsion (STP) previously envisioned for large spacecraft and capable of

  3. Diffracted field distributions from the HE sub 1 sub 1 mode in a hollow optical fibre for an atomic funnel

    CERN Document Server

    Ni Yun; Yin Jian Ping

    2003-01-01

    The diffracted near field distribution from an LP sub 0 sub 1 mode in a hollow optical fibre was recently calculated using a scalar model based on the weakly waveguiding approximation (Yoo et al 1999 J. Opt. B: Quantum Semiclass. Opt. 1 364). It showed a dominant Gaussian-like distribution with an increased axial intensity in the central region (not a doughnut-like distribution), so the diffracted output beam from the hollow fibre cannot be used to form an atomic funnel. Using exact solutions of the Maxwell equations based on a vector model, however, we calculate the electric field and intensity distributions of the HE sub 1 sub 1 mode in the same hollow fibre and study the diffracted near- and far-field distributions of the HE sub 1 sub 1 -mode output beam under the Fresnel approximation. We analyse and compare the differences between the output beams from the HE sub 1 sub 1 and LP sub 0 sub 1 modes. Our study shows that both the near- and far-field intensity distributions of the HE sub 1 sub 1 -mode output ...

  4. Fibre optic rail-foot cables for a pilot project of DB Netz AG

    Energy Technology Data Exchange (ETDEWEB)

    Nolte, Andreas [Draka Comteq Berlin GmbH und Co. KG, Berlin (Germany)

    2009-05-15

    At the request of Deutsche Bahn AG several cable manufacturers have developed a fibre optic cable for rail-foot installation. During the expected one-year test phase on a branch line in the Kiel area, the chosen suppliers' cables will be required to demonstrate their suitability for this purpose. This article describes the development and installation of the Draka Comteq cable. (orig.)

  5. Assessment of effect of nasal continuous positive pressure on laryngeal opening using fibre optic laryngoscopy

    OpenAIRE

    Gaon, P; Lee, S; Hannan, S; Ingram, D; Milner, A

    1999-01-01

    AIM—To assess the effect of nasal continuous positive airways pressure (CPAP) on the dimensions of the laryngeal opening.
METHODS—Nine preterm infants who had previously received ventilatory support for respiratory distress syndrome (RDS) were studied. All were receiving nasal CPAP. The laryngeal opening was visualised using a fibre optic video camera system. The ratio of width to length of the opening was measured on and off CPAP.
RESULTS—In eight of the infants the w...

  6. Optical fibre sensor coated with porous silica layers for gas and chemical vapour detection

    Czech Academy of Sciences Publication Activity Database

    Abdelghani, A.; Chovelon, J. M.; Jaffrezic-Renault, N.; Lacroix, M.; Gagnaire, H.; Veillas, C.; Berková, Daniela; Chomát, Miroslav; Matějec, Vlastimil

    B44, l/3 (1997), s. 495-498 ISSN 0925-4005 R&D Projects: GA ČR GA102/95/0871; GA ČR GA102/96/0939 Grant - others:EU COPERNICUS(XE) CIPA-CT94-0140 Keywords : nonelectric sensing devices * optical fibres * chemical sensor s * sol-gel processing Subject RIV: JB - Sensor s, Measurment, Regulation Impact factor: 0.858, year: 1997

  7. Fibre-optic thermometer using semiconductor-etalon sensor

    Science.gov (United States)

    Beheim, G.

    1986-01-01

    A fiber-optic thermometer is described which uses a thick-film SiC sensing etalon. The etalon's temperature-dependent phase shift is determined by analyzing its spectral reflectance, using an LED and a tunable Michelson interferometer. Temperatures from 20 to 1000 C are measured with better than 0.5 deg C resolution.

  8. Towards the Wetness Characterization of Soil Subsurface Using Fibre Optic Distributed Acoustic Sensing

    Science.gov (United States)

    Ciocca, F.; Bodet, L.; Simon, N.; Karaulanov, R.; Clarke, A.; Abesser, C.; Krause, S.; Chalari, A.; Mondanos, M.

    2017-12-01

    Active seismic methods combined with detectors deployed at the soil surface, such as vertical collinear geophones, have revealed great potential for hydrogeophysical characterization of the soil vadose zone. In particular, recent findings have highlighted a clear dependence of both P-waves arrival times and surface-wave dispersion on the local degree of soil saturation, visible at laboratory as well as at field scale. In this study, we investigate the sensitivity of a fibre optic Distributed Acoustic Sensor (DAS) to different soil saturation. In vertical seismic applications, DAS have proven to offer equal and often better performance compared to the geophones, with the advantage that a fibre optic cable, whose length can reach 40 km, replaces the array of geophones as sensing element. We present the response to active seismic tests of 20 m of fibre optic cable buried in a poorly permeable bare soil. Tests were conducted in different moments of the year, with saturation monitored by means of independent dielectric probes. Body-wave travel times as well as surface-wave dispersion are compared. Finally, we discuss the possibility to determine a site-specific relation between the Poisson ratio and the soil saturation. This research has been performed in the framework of the British National Environmental Research Council (NERC) funded Distributed intelligent Heat Pulse System (DiHPS) project and of the Marie Curie H2020 Research and Innovation Staff Exchange (RISE) consortium Hi-Freq.

  9. [Fibre optic-assisted endotracheal intubation through the laryngeal mask in children].

    Science.gov (United States)

    Weiss, M; Mauch, J; Becke, K; Schmidt, J; Jöhr, M

    2009-07-01

    Fibre optic-assisted tracheal intubation through the laryngeal mask airway is a simple and safe procedure for securing the airway in the paediatric patient with unexpected and known difficult tracheal intubation. Therefore, fibre optic-assisted tracheal intubation through the laryngeal mask airway represents a standard airway technique and must be part of clinical education and also regular training. However, the removal of the laryngeal mask airway over the tracheal tube is impaired by the short length of the tracheal tube, easily resulting in tube dislocation from the trachea. Among several techniques to overcome this problem, the Cook airway exchange catheter offers a reliable method not only for safe removal of the laryngeal mask over the tracheal tube but also for insertion of an adequate tracheal tube, particularly in paediatric patients. This is particularly important for cuffed tubes as the pilot balloon of the cuffed tube is too large to pass through laryngeal mask airway tubes size 2.5 and smaller. This presentation demonstrates fibre optic-assisted tracheal intubation through the laryngeal mask airway in children step-by-step and discusses its clinical implications. A list with compatible sizes of laryngeal mask airways, tracheal tubes and airway exchange catheters is also provided.

  10. Dual pO2/pCO2 fibre optic sensing film.

    Science.gov (United States)

    Davenport, John J; Hickey, Michelle; Phillips, Justin P; Kyriacou, Panayiotis A

    2017-05-15

    A fibre optic multi-sensor has been developed for biomedical sensing applications using a tip coating solution sensitive to both oxygen and carbon dioxide. An oxygen sensitive phosphorescence quenching complex based on platinum octaethylporphyrin (PtOEP) was combined with a carbon dioxide sensitive phosphorescence compound based on 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS). When excited by blue light (470 nm), the resultant coating had two fluorescent peaks at 515 nm (green) and 645 nm (red) which responded to partial pressure of CO 2 and O 2 respectively. The sensor was tested in vitro and shown to be able to measure CO 2 and O 2 simultaneously and in real time, with calibration constants of 0.0384 kPa -1 and 0.309 kPa -1 respectively. The O 2 sensitive peak received some overlap from the 515 nm peak (0.38% of peak intensity) as well as some cross-sensitivity (maximum, 5.1 kPa pCO 2 gave a measurement equivalent to 0.43 kPa of O 2 , a ratio of 0.08 : 1). However, these effects can be subtracted from measurements and no significant cross-sensitivity or overlap was seen in CO 2 measurements from O 2 . This novel compound presents great potential for use in medical sensors and we expect it to be important to a wide range of future applications.

  11. Reuse of polyethylene fibres from discarded fishing nets as reinforcement in gypsym-based materials

    DEFF Research Database (Denmark)

    Bertelsen, Ida Maria Gieysztor; Ottosen, Lisbeth M.

    In this study, the potential of reusing plastic fibres from discarded waste fishing nets of polyethylene (PE) as fibre reinforcement in gypsum-based building materials is investigated. The fishing nets were not reprocessed, but simply washed and cut to monofilament fibres by an industrial operation...

  12. Retinal nerve fibre layer thickness correlates with brain white matter damage in multiple sclerosis: a combined optical coherence tomography and diffusion tensor imaging study.

    Science.gov (United States)

    Scheel, Michael; Finke, Carsten; Oberwahrenbrock, Timm; Freing, Alina; Pech, Luisa-Maria; Schlichting, Jeremias; Sömmer, Carina; Wuerfel, Jens; Paul, Friedemann; Brandt, Alexander U

    2014-12-01

    We investigated the association of retinal nerve fibre layer thickness (RNFL) with white matter damage assessed by diffusion tensor imaging (DTI). Forty-four MS patients and 30 healthy subjects underwent optical coherence tomography. DTI was analysed with a voxel-based whole brain and region-based analysis of optic radiation, corpus callosum and further white matter. Correlations between RNFL, fractional anisotropy (FA) and other DTI-based parameters were assessed in patients and controls. RNFL correlated with optic radiation FA, but also with corpus callosum and remaining white matter FA. Our findings demonstrate that RNFL changes indicate white matter damage exceeding the visual pathway. © The Author(s), 2014.

  13. Azobenzene-Based Gel Coated Fibre Bragg Grating Sensor for Moisture Measurement

    Directory of Open Access Journals (Sweden)

    Mohammed Moniruzzaman

    2016-01-01

    Full Text Available A fibre Bragg grating sensor is coated with a novel polymer gel in order to investigate its suitability for nondestructive measurement of moisture in materials that can potentially lose their integrity due to moisture ingress. Absorption and desorption of moisture lead to swelling/shrinkage of an azobenzene-based gel, which induces a strain in the Bragg grating resulting in wavelength shifts. The results demonstrated that the amount of wavelength shift is linearly dependent on the amount of water ingress by the gel. The performance of the proposed optical fibre moisture sensor was found to be repeatable with no detectable hysteresis and has the potential to offer a low-cost route for monitoring moisture content.

  14. Rapid exchange ultra-thin microcatheter using fibre-optic sensing technology for measurement of intracoronary fractional flow reserve.

    Science.gov (United States)

    Diletti, Roberto; Van Mieghem, Nicolas M; Valgimigli, Marco; Karanasos, Antonis; Everaert, Bert R C; Daemen, Joost; van Geuns, Robert-Jan; de Jaegere, Peter P; Zijlstra, Felix; Regar, Evelyn

    2015-08-01

    The present report describes a novel coronary fractional flow reserve (FFR) system which allows FFR assessment using a rapid exchange microcatheter (RXi). The RXi microcatheter is compatible with standard 0.014" coronary guidewires facilitating lesion negotiation and FFR assessment in a wide range of coronary anatomies. In case of serial lesions, a microcatheter would have the important advantage of allowing multiple pullbacks while maintaining wire access to the vessel. The RXi is a fibre-optic sensor technology-based device. This technology might allow reduction in signal drift. The RXi microcatheter's fibre-optic sensor is located 5 mm from the distal tip. The microcatheter profile at the sensor site is 0.027"0.036". The segment of the catheter which is intended to reside within the target lesion is proximal to the sensor and has dimensions decreased to 0.020"0.025"; these dimensions are comparable to a 0.022" circular-shaped wire. The RXi microcatheter FFR system represents a novel technology that could allow easier lesion negotiation, maintaining guidewire position, facilitating pullbacks for assessment of serial lesions and simplifying the obtainment of post-intervention FFR measurements. The optical sensing technology could additionally result in less signal drift. Further investigations are required to evaluate the clinical value of this technology fully.

  15. Radiation effects on radiation-hardened KU and KS-4V optical fibres

    International Nuclear Information System (INIS)

    Ivanov, A.A.; Tugarinov, S.N.; Kaschuck, Y.A.; Krasilnikov, A.V.; Bender, S.E.

    1999-01-01

    The aim of this work was to test the un-pretreated and the hardened (H 2 -loaded and pre-irradiated) KS-4V and KU optical fibres in reactor environment by in-situ measurements of both the radiation-induced loss and the luminescence in the visible spectral region. Both the radio-luminescent and the transmission spectra were in-situ detected during irradiation by charge-coupled-device (CCD) linear detector in the visible spectral region of 400 to 700 nm. The radiation induced loss spectra at the fast neutron fluence of 2*10 6 n/cm 2 shows the hardened, H 2 -loading and pre-irradiating effects in the both KU and KS-4V fibres. KU un-pretreated fibre shows a big radiation absorption band of non-bridging oxygen centered at the wavelength of 630 nm. It appears that the KS-4V hardened fibre has a specific point in the loss spectrum in the vicinity of 460 nm. Other measurements were performed, particularly after reactor shutdown and at 3 different neutron fluences with constant neutron flux after restarting

  16. Asymptotic solutions of glass temperature profiles during steady optical fibre drawing

    KAUST Repository

    Taroni, M.

    2013-03-12

    In this paper we derive realistic simplified models for the high-speed drawing of glass optical fibres via the downdraw method that capture the fluid dynamics and heat transport in the fibre via conduction, convection and radiative heating. We exploit the small aspect ratio of the fibre and the relative orders of magnitude of the dimensionless parameters that characterize the heat transfer to reduce the problem to one- or two-dimensional systems via asymptotic analysis. The resulting equations may be readily solved numerically and in many cases admit exact analytic solutions. The systematic asymptotic breakdown presented is used to elucidate the relative importance of furnace temperature profile, convection, surface radiation and conduction in each portion of the furnace and the role of each in controlling the glass temperature. The models derived predict many of the qualitative features observed in real industrial processes, such as the glass temperature profile within the furnace and the sharp transition in fibre thickness. The models thus offer a desirable route to quick scenario testing, providing valuable practical information about the dependencies of the solution on the parameters and the dominant heat-transport mechanism. © 2013 Springer Science+Business Media Dordrecht.

  17. The Surface Measurement of Fibre Orientation Anisotropy and Misalignment Angle by Laser Diffraction

    OpenAIRE

    Pereira, Mário José Teixeira; Fiadeiro, Paulo Torrão; Jesus, M. E. P.; Silvy, Jacques

    2010-01-01

    The dimensional stability in fibre webs mainly depends of the fibre anisotropy and its orientation on the surfaces. These parameters are influenced during the manufacturing process, where the length and type of the fibres is determinant. The web quality control, in general, is performed based on the measurement of these parameters in the bulk of the fibre webs. This paper presents an optical laser diffraction method to measure the fibre anisotropy and the fibre orientation distribution only a...

  18. Optimal spacing between transmitting and receiving optical fibres in reflectance pulse oximetry

    International Nuclear Information System (INIS)

    Hickey, M; Kyriacou, P A

    2007-01-01

    Splanchnic ischaemia can ultimately lead to cellular hypoxia and necrosis, and may well contribute to the development of multiple organ failures and increased mortality. Therefore, it is of utmost importance to monitor abdominal organ blood oxygen saturation (SpO 2 ). Pulse oximetry has been widely accepted as a reliable method for monitoring oxygen saturation of arterial blood. Animal studies have also shown it to be effective in the monitoring of blood oxygen saturation in the splanchnic region. However, commercially available pulse oximeter probes are not suitable for the continuous assessment of SpO 2 in the splanchnic region. Therefore, there is a need for a new sensor technology that will allow the continuous measurement of SpO 2 in the splanchnic area pre-operatively, operatively and post-operatively. For this purpose, a new fibre optic sensor and processing system utilising the principle of reflectance pulse oximetry has been developed. The accuracy in the estimation of SpO 2 in pulse oximetry depends on the quality and amplitude of the photoplethysmographic (PPG) signal and for this reason an experimental procedure was carried out to examine the effect of the source-detector separation distance on the acquired PPG signals, and to ultimately select an optimal separation for the final design of the fibre-optic probe. PPG signals were obtained from the finger for different separation distances between the emitting and detecting fibres. Good quality PPG signals with large amplitudes and high signal-to-noise ratio were detected in the range of 3mm to 6mm. At separation distances between 1mm and 2mm, PPG signals were erratic with no resemblance to a conventional PPG signal. At separation distances greater than 6mm, the amplitudes of PPG signals were very small and not appropriate for processing. This investigation indicates the suitability of optical fibres as a new pulse oximetry sensor for estimating blood oxygen saturation (SpO 2 ) in the splanchnic region

  19. Optimal spacing between transmitting and receiving optical fibres in reflectance pulse oximetry

    Science.gov (United States)

    Hickey, M.; Kyriacou, P. A.

    2007-10-01

    Splanchnic ischaemia can ultimately lead to cellular hypoxia and necrosis, and may well contribute to the development of multiple organ failures and increased mortality. Therefore, it is of utmost importance to monitor abdominal organ blood oxygen saturation (SpO2). Pulse oximetry has been widely accepted as a reliable method for monitoring oxygen saturation of arterial blood. Animal studies have also shown it to be effective in the monitoring of blood oxygen saturation in the splanchnic region. However, commercially available pulse oximeter probes are not suitable for the continuous assessment of SpO2 in the splanchnic region. Therefore, there is a need for a new sensor technology that will allow the continuous measurement of SpO2 in the splanchnic area pre-operatively, operatively and post-operatively. For this purpose, a new fibre optic sensor and processing system utilising the principle of reflectance pulse oximetry has been developed. The accuracy in the estimation of SpO2 in pulse oximetry depends on the quality and amplitude of the photoplethysmographic (PPG) signal and for this reason an experimental procedure was carried out to examine the effect of the source-detector separation distance on the acquired PPG signals, and to ultimately select an optimal separation for the final design of the fibre-optic probe. PPG signals were obtained from the finger for different separation distances between the emitting and detecting fibres. Good quality PPG signals with large amplitudes and high signal-to-noise ratio were detected in the range of 3mm to 6mm. At separation distances between 1mm and 2mm, PPG signals were erratic with no resemblance to a conventional PPG signal. At separation distances greater than 6mm, the amplitudes of PPG signals were very small and not appropriate for processing. This investigation indicates the suitability of optical fibres as a new pulse oximetry sensor for estimating blood oxygen saturation (SpO2) in the splanchnic region.

  20. Refractive Index Measurement within a Photonic Crystal Fibre Based on Short Wavelength Diffraction

    Directory of Open Access Journals (Sweden)

    Nathaniel Groothoff

    2007-10-01

    Full Text Available A new class of refractive index sensors using solid core photonic crystal fibres isdemonstrated. Coherent scattering at the cladding lattice is used to optically characterizematerials inserted into the fibre holes. The liquid to solid phase transition of water uponfreezing to ice 1h is characterized by determining the refractive index.

  1. low pump power photonic crystal fibre amplifiers

    DEFF Research Database (Denmark)

    Hougaard, Kristian G.; Broeng, Jes; Bjarklev, Anders Overgaard

    2003-01-01

    Designs of low pump power optical amplifiers, based on photonic crystal fibres are presented. The potential of these fibre amplifiers is investigated, and it is demonstrated that such amplifiers may deliver gains of more than 15 dB at 1550 nm with less than 1 mW of optical pump power....

  2. A novel approach to the sensing of liquid density using a plastic optical fibre cantilever beam

    Science.gov (United States)

    Kulkarni, Atul; Kim, Youngjin; Kim, Taesung

    2009-01-01

    This article reports for the first time the use of a plastic optical fibre (POF) cantilever beam to measure the density of a liquid. The sensor is based on the Archimedes buoyancy principle. The sensor consists of a POF bonded on the surface of a metal beam in the form of a cantilever configuration, and at the free end of the beam a displacer is attached. Due to the apparent loss of the true weight of the displacer there is a deflection in the cantilever beam, which causes macro bending in the POF. The loss of intensity due to macro bending of the POF is a measure of the density of the liquid under test. The variation of weight loss with the density of different liquids showed that the weight loss is proportional to density. This sensor is capable of detecting the weight loss with respect to their densities even for liquids having close values of density like distilled water, tap water, and milk of various brands. The resolution of the sensor is observed to be 1.1 mg cm-3.

  3. Sky subtraction at the Poisson limit with fibre-optic multiobject spectroscopy

    Science.gov (United States)

    Sharp, R.; Parkinson, H.

    2010-11-01

    We report on the limitations of sky-subtraction accuracy for long-duration fibre-optic multiobject spectroscopy of faint astronomical sources during long-duration exposures. We show that while standard sky subtraction techniques yield accuracies consistent with the Poisson noise limit for exposures of 1h duration, there are large-scale systematic defects that inhibit the sensitivity gains expected on the summation of longer duration exposures. For the AAOmega system at the Anglo-Australian Telescope, we identify a limiting systematic sky-subtraction accuracy, which is reached after integration times of 4-10h. We show that these systematic defects can be avoided through the use of the fibre nod-and-shuffle (N+S) observing mode, but with a potential cost in observing efficiency. Finally, we demonstrate that these disadvantages can be overcome through the application of a Principal Components Analysis (PCA) sky-subtraction routine. Such an approach minimize systematic residuals across long-duration exposures, allowing deep integrations. We apply the PCA approach to over 200h of on-sky observations and conclude that for the AAOmega system, the residual error in long-duration observations falls at a rate proportional to τ-0.32 in contrast to the τ-0.5 rate expected from theoretical considerations. With this modest rate of decline, the PCA approach represents a more efficient mode of observation than the N+S technique for observations in the sky limited regime with durations of 10-100h (even before accounting for the additional signal-to-noise ratio and targeting efficiency losses often associated with the N+S technique). This conclusion has important implications for the observing strategies of the next generation of fibre-optics redshift surveys with existing facilities as well as design implications for fibre-optic systems destined for new facilities. It argues against the use of the inherently inefficient N+S technique for faint object fibre-optic survey

  4. Comparison of two retinal nerve fibre layer thickness measurement patterns of RTvue optical coherence tomography.

    Science.gov (United States)

    Li, Shuning; Wang, Xiaozhen; Wu, Gewei; Fu, Jing; Li, Songfeng; Wan, Xiuhua; Wang, Ningli

    2011-04-01

    To evaluate the agreement and repeatability between operator-dependent centring and automatic centring retinal nerve fibre layer thickness measurement patterns (RNFL3.45 and NHM4) of RTvue optical coherence tomography in normal and glaucomatous eyes.   Cross-sectional observational study. A total of 153 eyes from 149 normal subjects and subjects with glaucoma were analysed.   The retinal nerve fibre layer thickness was measured using RNFL3.45 and NHM4 three times on the same day to determine the repeatability and agreement between the two scan patterns. Student's paired t-testing, intra-class correlation coefficient, coefficient of variation, test-retest viability, Pearson's correlation coefficient and Bland-Altman analysis of retinal nerve fibre layer thickness measurements. The difference between RNFL3.45 and NHM4 measurements was statistically significant by paired t-testing (P=0.003) only in severe glaucoma group. The Pearson's correlation test showed a high degree of correlation of the mean retinal nerve fibre layer thickness (r=0.949). Bland-Altman plots showed that the differences between RNFL3.45 and NHM4 were smaller at thicker retinal nerve fibre layer values, but larger at thinner retinal nerve fibre layer values. The intra-class correlation coefficient for RNFL3.45 (and lower 95% confidence interval) in normal and glaucomatous eyes was 0.990 (0.985 confidence interval) and 0.997 (0.995 confidence interval), respectively. The intra-class correlation coefficient for NHM4 in normal and glaucomatous eyes was 0.989 (0.983 confidence interval) and 0.995 (0.992 confidence interval), respectively. The test-retest variability for RNFL3.45 and NHM4 ranged from 3.98 to 9.75µm in normal eyes, and from 4.10 to 13.34µm in glaucomatous eyes. Measurements of retinal nerve fibre layer thickness by RNFL3.45 and NHM4 are in good agreement. © 2011 The Authors. Clinical and Experimental Ophthalmology © 2011 Royal Australian and New Zealand College of

  5. Fast bragg grating inscription in PMMA polymer optical fibres: Impact of thermal pre-treatment of preforms

    DEFF Research Database (Denmark)

    Marques, Carlos A. F.; Pospori, Andreas; Demirci, Gökhan

    2017-01-01

    In this work, fibre Bragg gratings (FBGs) were inscribed in two different undoped poly- (methyl methacrylate) (PMMA) polymer optical fibres (POFs) using different types of UV lasers and their inscription times, temperature and strain sensitivities are investigated. The POF Bragg gratings (POFBGs...... preform is not specifically pre-treated need longer inscription time than the fibres drawn where both preforms have been pre-annealed at 80 °C for 2 weeks. Using both UV lasers, for the latter fibre much less inscription time is needed compared to another homemade POF. The properties of a POF fabricated...... with both preforms thermally well annealed are different from those in which just one preform step process is thermally treated, with the first POFs being much less sensitive to thermal treatment. The influence of annealing on the strain and temperature sensitivities of the fibres prior to FBG inscription...

  6. Retinal nerve fibre layer imaging: comparison of Cirrus optical coherence tomography and Heidelberg retinal tomograph 3.

    Science.gov (United States)

    Kratz, Assaf; Lim, Ridia; Rush, Ryan; Sheth, Saumil; Goldberg, Ivan

    2013-12-01

    The purpose of this study was to analyze the relationship between retinal nerve fibre layer thickness measured by spectral domain optical coherence tomography and confocal scanning laser ophthalmoscope. Prospective, cross-sectional study. Hospital setting. One hundred seventy-three subjects (85 glaucoma and 88 normal subjects). One eye from each individual was selected randomly for imaging by the spectral domain Cirrus optical coherence tomography and Heidelberg retinal tomograph 3. Global thickness and measurements at the four quadrants around the optic disc. Measurements as determined by Heidelberg retinal tomograph 3 were significantly larger than measurements done by Cirrus optical coherence tomography (respectively in mm, for global thickness: 200.0 ± 87.2 and 80.7 ± 14.7; for temporal quadrant: 75.3 ± 31.9 and 59.1 ± 13.8; for superior quadrant: 223.2 ± 128.4 and 97.7 ± 20.9; for nasal quadrant: 208.0 ± 102.9 and 66.8 ± 11.8; and for inferior quadrant: 224.4 ± 116.9 and 99.1 ± 26.6, for all P fibre layer thickness. The normative diagnostic classification of the two technologies may not agree. The results preclude interchangeable use of these measurements in clinical practice. © 2013 Royal Australian and New Zealand College of Ophthalmologistss.

  7. THE USE OF SISAL FIBRE AS REINFORCEMENT IN CEMENT BASED COMPOSITES

    Directory of Open Access Journals (Sweden)

    Romildo Dias Tolêdo Filho

    1999-08-01

    Full Text Available ABSTRACT The inclusion of fibre reinforcement in concrete, mortar and cement paste can enhance many of the engineering properties of the basic materials, such as fracture toughness, flexural strength and resistance to fatigue, impact, thermal shock and spalling. In recent years, a great deal of interest has been created worldwide on the potential applications of natural fibre reinforced, cement based composites. Investigations have been carried out in many countries on various mechanical properties, physical performance and durability of cement based matrices reinforced with naturally occurring fibres including sisal, coconut, jute, bamboo and wood fibres. These fibres have always been considered promising as reinforcement of cement based matrices because of their availability, low cost and low consumption of energy. In this review, the general properties of the composites are described in relation to fibre content, length, strength and stiffness. A chronological development of sisal fibre reinforced, cement based matrices is reported and experimental data are provided to illustrate the performance of sisal fibre reinforced cement composites. A brief description on the use of these composite materials as building products has been included. The influence of sisal fibres on the development of plastic shrinkage in the pre-hardened state, on tensile, compressive and bending strength in the hardened state of mortar mixes is discussed. Creep and drying shrinkage of the composites and the durability of natural fibres in cement based matrices are of particular interest and are also highlighted. The results show that the composites reinforced with sisal fibres are reliable materials to be used in practice for the production of structural elements to be used in rural and civil construction. This material could be a substitute asbestos-cement composite, which is a serious hazard to human and animal health and is prohibited in industrialized countries. The

  8. Metrological 2iOF fibre-optic system for position and displacement measurement with 31 pm resolution

    Science.gov (United States)

    Orłowska, Karolina; Świåtkowski, Michał; Kunicki, Piotr; Gotszalk, Teodor

    2018-04-01

    In the present paper, we describe a high sensitivity intensity fibre-optic displacement sensor with tens of picometre resolution combined with a sub-picometre resolution interferometric calibration system. Both integrated components form the so-called "2 in one ferrule" system 2iOF. The design and construction of the presented device depend on integrating two sensors' systems within one fibre-optic measuring head, which allows performing in situ calibration process with no additional time-consuming adjustment procedure. The resolution of the 2iOF system is 31 pm/Hz1/2 obtained with an interferometric Fabry-Perot based calibration system—providing accuracy better than tens of fm/Hz1/2 within 1 MHz bandwidth in the measurement range of up to 100 μm. The direct response from the intensity sensor is then the 2iOF output one. It is faster and more convenient to analyze in comparison, with much better resolution (3 orders of magnitude higher) but on the other hand also more time consuming and dependent on the absolute sample position interferometer. The proposed system is flexible and open to various applications. We will present the results of the piezoelectrical actuator displacement measurements, which were performed using the developed system.

  9. Fibre optic gyroscope as instrumental challenge for rotational seismology

    Science.gov (United States)

    Kurzych, Anna; Jaroszewicz, Leszek R.; Krajewski, Zbigniew; Sakowicz, Bartosz; Kowalski, Jerzy K.; Marć, Paweł

    2017-04-01

    Rotational Seismology caused highly interest in investigation of rotational movements generated by earthquake, mines and existing in engineering structures. The most oppressive aspect of research in this field is technical requirements for sensors. However, the instruments basing on the Sagnac effect seem to be the most appropriate to investigate rotational effects due to the fact that they are entirely insensitive to translational motion and are able to measure rotation rate in wide frequency and amplitude band. The paper presents a new device FOSREM which, based on FOG, possesses special solutions that makes it perfect, in author knowledge, for any rotation sensing.

  10. A self-referenced reflectance sensor for the detection of lead and other heavy metal ions using optical fibres

    International Nuclear Information System (INIS)

    Guillemain, H; Rajarajan, M; Sun, T; Grattan, K T V

    2009-01-01

    A self-referenced optical fibre sensor for monitoring heavy metals, especially lead, has been developed and evaluated and the results obtained are discussed in detail in this paper. The sensor probe builds on concepts in prior work, creating a small, compact and portable device using an indicator immobilized at the fibre end. It functions in the visible part of the spectrum where the attenuation caused by fibre transmission is small and it offers a possible solution to the need for devices to be used in the field. This represents on-going research where the factors affecting the probe design and immobilization procedure used are considered and solutions offered

  11. Fibre-Optic IR-Spectroscopy for Biomedical Diagnostics

    OpenAIRE

    Bindig, Uwe; Gersonde, Ingo; Meinke, Martina; Becker, Yukiyo; Müller, Gerhard

    2003-01-01

    The use of microscopy is a valuable means of gaining vital information for medical diagnostics. Due to a number of recent technological developments advances have been made in IR microscopy and in particular, rapid detection methods. Microscopic examination methods usually involve sampling followed by a method of sample purification or preparation. The advantages of the IR analytical method are that it is based on a direct, non‒destructive measurement of sample material and that the resulting...

  12. France’s State of the Art Distributed Optical Fibre Sensors Qualified for the Monitoring of the French Underground Repository for High Level and Intermediate Level Long Lived Radioactive Wastes

    Science.gov (United States)

    Delepine-Lesoille, Sylvie; Girard, Sylvain; Landolt, Marcel; Bertrand, Johan; Planes, Isabelle; Boukenter, Aziz; Marin, Emmanuel; Humbert, Georges; Leparmentier, Stéphanie; Auguste, Jean-Louis; Ouerdane, Youcef

    2017-01-01

    This paper presents the state of the art distributed sensing systems, based on optical fibres, developed and qualified for the French Cigéo project, the underground repository for high level and intermediate level long-lived radioactive wastes. Four main parameters, namely strain, temperature, radiation and hydrogen concentration are currently investigated by optical fibre sensors, as well as the tolerances of selected technologies to the unique constraints of the Cigéo’s severe environment. Using fluorine-doped silica optical fibre surrounded by a carbon layer and polyimide coating, it is possible to exploit its Raman, Brillouin and Rayleigh scattering signatures to achieve the distributed sensing of the temperature and the strain inside the repository cells of radioactive wastes. Regarding the dose measurement, promising solutions are proposed based on Radiation Induced Attenuation (RIA) responses of sensitive fibres such as the P-doped ones. While for hydrogen measurements, the potential of specialty optical fibres with Pd particles embedded in their silica matrix is currently studied for this gas monitoring through its impact on the fibre Brillouin signature evolution. PMID:28608831

  13. Irradiation studies of multimode optical fibres for use in ATLAS front-end links

    CERN Document Server

    Mahout, G; Andrieux, M L; Arvidsson, C B; Charlton, D G; Dinkespiler, B; Dowell, John D; Gallin-Martel, L; Homer, R James; Jovanovic, P; Kenyon, Ian Richard; Kuyt, G; Lundqvist, J M; Mandic, I; Martin, O; Shaylor, H R; Stroynowski, R; Troska, Jan K; Wastie, R L; Weidberg, A R; Wilson, J A; Ye, J

    2000-01-01

    The radiation tolerance of three multimode optical fibres has been investigated to establish their suitability for the use in the front- end data links of the ATLAS experiment. Both gamma and neutron irradiation studies are reported. A step-index fibre with a pure silica core showed an induced attenuation of ~0.05 dB/m at 330 kGy (Si) and 1*10/sup 15/ n(1 MeV Si)/cm/sup 2/ and is suitable for use with the inner detector links which operate at 40-80 Mb/s. A graded- index fibre with a predominantly germanium-doped core exhibits an induced attenuation of ~0.1 dB/m at 800 Gy(Si) and 2*10/sup 13/ n(1 MeV Si)/cm/sup 2/ and is suitable for the calorimeter links which operate at 1.6 Gb/s. Measurements of the dose rate dependence of the induced attenuation indicate that the attenuation in ATLAS will be lower. (30 refs).

  14. Irradiation studies of multimode optical fibres for use in ATLAS front-end links

    International Nuclear Information System (INIS)

    Mahout, G.; Pearce, M.; Andrieux, M-L.; Arvidsson, C-B.; Charlton, D.G.; Dinkespiler, B.; Dowell, J.D.; Gallin-Martel, L.; Homer, R.J.; Jovanovic, P.; Kenyon, I.R.; Kuyt, G.; Lundquist, J.; Mandic, I.; Martin, O.; Shaylor, H.R.; Stroynowski, R.; Troska, J.; Wastie, R.L.; Weidberg, A.R.; Wilson, J.A.; Ye, J.

    2000-01-01

    The radiation tolerance of three multimode optical fibres has been investigated to establish their suitability for the use in the front-end data links of the ATLAS experiment. Both gamma and neutron irradiation studies are reported. A step-index fibre with a pure silica core showed an induced attenuation of ∼0.05 dB/m at 330 kGy(Si) and 1x10 15 n(1 MeV Si)/cm 2 and is suitable for use with the inner detector links which operate at 40-80 Mb/s. A graded-index fibre with a predominantly germanium-doped core exhibits an induced attenuation of ∼0.1 dB/m at 800 Gy(Si) and 2x10 13 n(1 MeV Si)/cm 2 and is suitable for the calorimeter links which operate at 1.6 Gb/s. Measurements of the dose rate dependence of the induced attenuation indicate that the attenuation in ATLAS will be lower

  15. Hybrid RSOA and fibre raman amplified long reach feeder link for WiMAX-on-fibre

    DEFF Research Database (Denmark)

    Amaya Fernández, Ferney Orlando; Martinez, Javier; Yu, Xianbin

    2009-01-01

    A distributed fibre Raman amplified long reach optical access feeder link using a reflective semiconductor optical amplifier in the remote base station is experimentally demonstrated for supporting WiMAXover- fibre transmission. The measured values for the error vector magnitude for quadrature ph...... phase shift keying and 16-ary quadrature amplitude modulation after 40 km of fibre transmission meet the IEEE 820.16 standard requirements...

  16. Elie: Saint Eustache fibre Optic Field Trial project evaluation report, volume 4

    Science.gov (United States)

    Harris, K. B.; Tough, G. A.; Akgun, M. B.

    1985-03-01

    The Elie - St. Eustache Fibre Optic Field Trial has provided voice, data and video communications through an integrated services access system to 150 residential and small business participants in a rural area. The trial has generated a wealth of information in all stages of the project such as design, implementation and operation. The uniqueness of the system makes it worthwhile to document in detail all the experience gained for use by national and international parties who have an interest in the design, manufacture and operation of similar systems in the future.

  17. Investigation of bandwidth loading in optical fibre transmission using amplified spontaneous emission noise.

    Science.gov (United States)

    Elson, Daniel J; Saavedra, Gabriel; Shi, Kai; Semrau, Daniel; Galdino, Lidia; Killey, Robert; Thomsen, Benn C; Bayvel, Polina

    2017-08-07

    The use of spectrally shaped amplified spontaneous emission noise (SS-ASE) as a method for emulating interfering channels in optical fibre transmission systems has been studied. It is shown that the use of SS-ASE leads to a slightly pessimistic performance relative to the use of conventionally modulated interfering channels in the nonlinear regime. The additional nonlinear interference noise (on the channel under test), due to the Gaussian nature of SS-ASE, has been calculated using a combination of the Gaussian noise (GN) and enhanced GN (EGN) models for the entire C-band (4.5 THz) and experimentally shown to provide a lower bound for transmission performance.

  18. Impact of initial pulse shape on the nonlinear spectral compression in optical fibre

    Science.gov (United States)

    Boscolo, Sonia; Chaussard, Frederic; Andresen, Esben; Rigneault, Hervé; Finot, Christophe

    2018-02-01

    We theoretically study the effects of the temporal intensity profile of the initial pulse on the nonlinear propagation spectral compression process arising from nonlinear propagation in an optical fibre. Various linearly chirped input pulse profiles are considered, and their dynamics is explained with the aid of time-frequency representations. While initially parabolic-shaped pulses show enhanced spectral compression compared to Gaussian pulses, no significant spectral narrowing occurs when initially super-Gaussian pulses are used. Triangular pulses lead to a spectral interference phenomenon similar to the Fresnel bi-prism experiment.

  19. In situ study of the epoxy cure process using a fibre-optic sensor

    Czech Academy of Sciences Publication Activity Database

    Chailleux, E.; Salvia, M.; Jaffrezic-Renault, N.; Matějec, Vlastimil; Kašík, Ivan

    2001-01-01

    Roč. 10, č. 2 (2001), s. 194-202 ISSN 0964-1726. [SPIE Annual International Symposium on Smart Structures and Materials /8./. Newport Beach, 04.03.2001-08.03.2001] R&D Projects: GA ČR GA102/99/0548; GA AV ČR KSK2067107 Projekt 07/01:4074 Institutional research plan: CEZ:AV0Z2067918 Keywords : fibre optic sensors * process monitoring Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.199, year: 2001

  20. Power consumption in multicore fibre networks

    DEFF Research Database (Denmark)

    Nooruzzaman, Md; Jain, Saurabh; Jung, Yongmin

    2017-01-01

    We study potential energy savings in MCF-based networks compared to SMF-based ones in a Pan-European network topology based on the power consumption of recently fabricated cladding-pumped multi-core optical fibre amplifiers.......We study potential energy savings in MCF-based networks compared to SMF-based ones in a Pan-European network topology based on the power consumption of recently fabricated cladding-pumped multi-core optical fibre amplifiers....

  1. Surface modification of cellulose-based fibres for use in advanced materials

    OpenAIRE

    Utsel, Simon

    2010-01-01

    The awareness of our need for a sustainable society has encouraged the search for renewable, high quality materials that can replace oil-based products. This, in combination with increased competition in the forest industry, has stimulated a lot of research into different types of wood-based materials where cellulose-rich fibres are combined with different types of polymers. There is hence a large need to develop efficient fibre modification techniques by which the fibres can be tailored to o...

  2. Review of the Usefulness of Various Rotational Seismometers with Laboratory Results of Fibre-Optic Ones Tested for Engineering Applications

    Directory of Open Access Journals (Sweden)

    Leszek R. Jaroszewicz

    2016-12-01

    Full Text Available Starting with descriptions of rotational seismology, areas of interest and historical field measurements, the fundamental requirements for rotational seismometers for seismological and engineering application are formulated. On the above basis, a review of all existing rotational seismometers is presented with a description of the principles of their operation as well as possibilities to fulfill formulated requirements. This review includes mechanical, acoustical, electrochemical and optical devices and shows that the last of these types are the most promising. It is shown that optical rotational seismometer based on the ring-laser gyroscope concept is the best for seismological applications, whereas systems based on fiber-optic gyroscopes demonstrate parameters which are also required for engineering applications. Laboratory results of the Fibre-Optic System for Rotational Events & Phenomena Monitoring using a small 1-D shaking table modified to generate rotational excitations are presented. The harmonic and time-history tests demonstrate its usefulness for recording rotational motions with rates up to 0.25 rad/s.

  3. New role for communication fibre optic cables in water utility for leak detection on main water pipeline

    Directory of Open Access Journals (Sweden)

    Graovac Radojica M.

    2015-01-01

    Full Text Available During construction of main water pipeline it is usual practice to lay fibre optic communication cable along water pipe. This cable is one of the up to date communication media which is used for the connection purposes of water control SCADA equipment as well as for establishing of telephone communication between water utility plants. By developing of new electronic equipment known as DTS (Distributed Temperature Sensing and DAS (Distributed Acoustic Sensing equipment it has been opened the possibility, with this equipment and by utilizing of dedicated optical fibres of optical fibre communication cable as a sensor, to detect leakage point by temperature monitoring or monitoring of acoustic changes along water pipeline (as detection of temperature change of soil at leakage point or detection of acoustic change at leakage point.

  4. Optimal spacing between transmitting and receiving optical fibres in reflectance pulse oximetry

    Energy Technology Data Exchange (ETDEWEB)

    Hickey, M; Kyriacou, P A [School of Engineering and Mathematical Sciences, City University, Northampton Square, London, EC1V 0HB (United Kingdom)

    2007-10-15

    Splanchnic ischaemia can ultimately lead to cellular hypoxia and necrosis, and may well contribute to the development of multiple organ failures and increased mortality. Therefore, it is of utmost importance to monitor abdominal organ blood oxygen saturation (SpO{sub 2}). Pulse oximetry has been widely accepted as a reliable method for monitoring oxygen saturation of arterial blood. Animal studies have also shown it to be effective in the monitoring of blood oxygen saturation in the splanchnic region. However, commercially available pulse oximeter probes are not suitable for the continuous assessment of SpO{sub 2} in the splanchnic region. Therefore, there is a need for a new sensor technology that will allow the continuous measurement of SpO{sub 2} in the splanchnic area pre-operatively, operatively and post-operatively. For this purpose, a new fibre optic sensor and processing system utilising the principle of reflectance pulse oximetry has been developed. The accuracy in the estimation of SpO{sub 2} in pulse oximetry depends on the quality and amplitude of the photoplethysmographic (PPG) signal and for this reason an experimental procedure was carried out to examine the effect of the source-detector separation distance on the acquired PPG signals, and to ultimately select an optimal separation for the final design of the fibre-optic probe. PPG signals were obtained from the finger for different separation distances between the emitting and detecting fibres. Good quality PPG signals with large amplitudes and high signal-to-noise ratio were detected in the range of 3mm to 6mm. At separation distances between 1mm and 2mm, PPG signals were erratic with no resemblance to a conventional PPG signal. At separation distances greater than 6mm, the amplitudes of PPG signals were very small and not appropriate for processing. This investigation indicates the suitability of optical fibres as a new pulse oximetry sensor for estimating blood oxygen saturation (SpO{sub 2}) in

  5. Radiation dose to radiosensitive organs in PET/CT myocardial perfusion examination using versatile optical fibre

    Science.gov (United States)

    Salasiah, M.; Nordin, A. J.; Fathinul Fikri, A. S.; Hishar, H.; Tamchek, N.; Taiman, K.; Ahmad Bazli, A. K.; Abdul-Rashid, H. A.; Mahdiraji, G. A.; Mizanur, R.; Noor, Noramaliza M.

    2013-05-01

    Cardiac positron emission tomography (PET) provides a precise method in order to diagnose obstructive coronary artery disease (CAD), compared to single photon emission tomography (SPECT). PET is suitable for obese and patients who underwent pharmacologic stress procedures. It has the ability to evaluate multivessel coronary artery disease by recording changes in left ventricular function from rest to peak stress and quantifying myocardial perfusion (in mL/min/g of tissue). However, the radiation dose to the radiosensitive organs has become crucial issues in the Positron Emission Tomography/Computed Tomography(PET/CT) scanning procedure. The objective of this study was to estimate radiation dose to radiosensitive organs of patients who underwent PET/CT myocardial perfusion examination at Centre for Diagnostic Nuclear Imaging, Universiti Putra Malaysia in one month period using versatile optical fibres (Ge-B-doped Flat Fibre) and LiF (TLD-100 chips). All stress and rest paired myocardial perfusion PET/CT scans will be performed with the use of Rubidium-82 (82Rb). The optic fibres were loaded into plastic capsules and attached to patient's eyes, thyroid and breasts prior to the infusion of 82Rb, to accommodate the ten cases for the rest and stress PET scans. The results were compared with established thermoluminescence material, TLD-100 chips. The result shows that radiation dose given by TLD-100 and Germanium-Boron-doped Flat Fiber (Ge-B-doped Flat Fiber) for these five organs were comparable to each other where the p>0.05. For CT scans,thyroid received the highest dose compared to other organs. Meanwhile, for PET scans, breasts received the highest dose.

  6. Comparison of three types of fibre optic hydrogen sensors within the frame of CryoFOS project

    Science.gov (United States)

    Guemes, J. Alfredo; Pintado, J. M.; Frovel, M.; Olmo, E.; Obst, A.

    2005-05-01

    Three different sensors for hydrogen detection have been built and tested within a research project for the European Space Agency. One type is a FBG coated with a palladium layer, detecting the hydrogen by metal hindrance, the strains transmitted to the grating by shear. It works only as a detector and can not quantify the H2 percentage in a gas mixture. A main drawback, common with all palladium based sensors, was a strong temperature dependence, which makes its response time too large at low temperatures. The other two types were intensity based sensors; one of them was a micromirror, with a palladium thin layer at the cleaved end, detecting changes in the backreflected light. The other one as a tapered fibre coated also with palladium; hydrogen will change the refractive index of the palladium, and consequently the amount of losses in the evanescent wave. A trade-off analysis of sensor performances was done, comparing reproducibility, repetitiveness, robustness, multiplexability, response time and cost. FBG sensor was found to be the most reliable sensor among the optical fibres sensors considered, and the preferred one for space applications.

  7. Geometric optimisation of an accurate cosine correcting optic fibre coupler for solar spectral measurement

    Science.gov (United States)

    Cahuantzi, Roberto; Buckley, Alastair

    2017-09-01

    Making accurate and reliable measurements of solar irradiance is important for understanding performance in the photovoltaic energy sector. In this paper, we present design details and performance of a number of fibre optic couplers for use in irradiance measurement systems employing remote light sensors applicable for either spectrally resolved or broadband measurement. The angular and spectral characteristics of different coupler designs are characterised and compared with existing state-of-the-art commercial technology. The new coupler designs are fabricated from polytetrafluorethylene (PTFE) rods and operate through forward scattering of incident sunlight on the front surfaces of the structure into an optic fibre located in a cavity to the rear of the structure. The PTFE couplers exhibit up to 4.8% variation in scattered transmission intensity between 425 nm and 700 nm and show minimal specular reflection, making the designs accurate and reliable over the visible region. Through careful geometric optimization near perfect cosine dependence on the angular response of the coupler can be achieved. The PTFE designs represent a significant improvement over the state of the art with less than 0.01% error compared with ideal cosine response for angles of incidence up to 50°.

  8. High-speed ADC and DAC modules with fibre optic interconnections for telecom satellites

    Science.gov (United States)

    Heikkinen, Veli; Juntunen, Eveliina; Karppinen, Mikko; Kautio, Kari; Ollila, Jyrki; Sitomaniemi, Aila; Tanskanen, Antti; Casey, Rory; Scott, Shane; Gachon, Hélène; Sotom, Michel; Venet, Norbert; Toivonen, Jaakko; Tuominen, Taisto; Karafolas, Nikos

    2017-11-01

    The flexibility required for future telecom payloads calls for the introduction of more and more digital processing capabilities. Aggregate data throughputs of several Tbps will have to be handled onboard, thus creating the need for effective, ADCDSP and DACDSP highspeed links. ADC and DAC modules with optical interconnections is an attractive option as it can solve easily the transmission and routing of the expected huge amount of data. This technique will enable to increase the bandwidth and/or the number of beams/channels to be treated, or to support advanced digital processing architectures including beam forming. We realised electrooptic ADC and DAC modules containing an 8 bit, 2 GSa/s A/D converter and a 12 bit, 2 GSa/s D/A converter. The 4channel parallel fibre optic link employs 850nm VCSELs and GaAs PIN photodiodes coupled to 50/125μm fibre ribbon cable. ADCDSP and DSPDAC links both have an aggregate data rate of 25 Gbps. The paper presents the current status of this development.

  9. Wavelength conversion of 80 Gbit/s optical DQPSK using FWM in a highly non-linear fibre

    DEFF Research Database (Denmark)

    Tokle, Torger; Geng, Yan; Peucheret, Christophe

    We present, for the first time, wavelength conversion of 80 Gbit/s optical DQPSK. The wavelength conversion is achieved using FWM in a highly non-linear fibre. We demonstrate a conversion power penalty as low as 2.8 dB.......We present, for the first time, wavelength conversion of 80 Gbit/s optical DQPSK. The wavelength conversion is achieved using FWM in a highly non-linear fibre. We demonstrate a conversion power penalty as low as 2.8 dB....

  10. Effects of the gamma-ray irradiation on the optical absorption of pure silica core single-mode fibres in the visible and NIR range

    International Nuclear Information System (INIS)

    Calderon, A.; Calvo, E.; Figueroa, C.F.; Martinez-Rivero, C.; Matorras, F.; Rodrigo, T.; Sobron, M.; Vila, I.; Virto, A.L.; Arce, P.; Barcala, J.M.; Ferrando, A.; Josa, M.I.; Luque, J.M.; Molinero, A.; Navarrete, J.; Oller, J.C.; Yuste, C.

    2005-01-01

    Optical absorption induced by photon radiation was evaluated for several commercial pure silica core, single mode, optical fibres. The study was performed for three different wavelengths: 630, 670 and 785 nm. We have identified a fibre whose induced transmission loss stays below 1 dB/m after 300 kGy gamma-ray irradiation

  11. The relationship between the optical density of cataract and its influence on retinal nerve fibre layer thickness measured with spectral domain optical coherence tomography.

    Science.gov (United States)

    Kok, Pauline H B; van den Berg, Thomas J T P; van Dijk, Hille W; Stehouwer, Marilette; van der Meulen, Ivanka J E; Mourits, Maarten P; Verbraak, Frank D

    2013-08-01

    The purpose of this study was to model the influence of cataract on Spectral Domain Optical Coherence Tomography (SDOCT) image quality and Retinal Nerve Fibre Layer (RNFL) thickness measurements. SDOCT images, made with two different devices (3DOCT-1000, Topcon and Cirrus HD-OCT), before and after cataract surgery were compared and judged against measurements from normal subjects using artificial filters simulating the effects of cataract. Optical density of the images was calculated based on a mathematical model described previously. In total, forty-eight eyes were included for pre- and postoperative cataract extraction measurements. OCT image quality significantly (p optical density and change in RNFL thickness (R = 0.941, p optical density of cataract and the cataract-induced underestimation was however limited, and mean difference ± SD between predicted and measured RNFL thickness were 1.68 ± 7.55 (3DOCT-1000) and 3.71 ± 2.97 (Cirrus HD-OCT) micron. A linear relationship exists between OCT-effective optical density of cataract and underestimation of RNFL thickness measured with OCT. This finding holds promise to correct for cataract-induced changes in RNFL measurements, but will differ for each type of OCT device. © 2012 The Authors. Acta Ophthalmologica © 2012 Acta Ophthalmologica Scandinavica Foundation.

  12. Interocular symmetry of retinal nerve fibre layer thickness in healthy eyes: a spectral-domain optical coherence tomographic study.

    Science.gov (United States)

    Hwang, Young Hoon; Song, Miryoung; Kim, Yong Yeon; Yeom, Dong Ju; Lee, Joo Hwa

    2014-11-01

    This study was performed to investigate the interocular symmetry of peripapillary retinal nerve fibre layer (RNFL) thickness, as measured by Cirrus high-definition spectral-domain optical coherence tomography (OCT), in healthy eyes. A wide range of subject ages and refractive errors was examined. The retinal nerve fibre layer thickness was measured in 1,234 healthy eyes from 617 subjects using OCT. Interocular differences (right eye minus left eye) in global area and quadrant nerve fibre layer thicknesses were measured. The effect of age and refractive error on interocular nerve fibre layer thickness difference was also examined. Means (and standard deviations) of subjects' ages and average subject refractive errors were 36.4 ± 19.8 years (range: five to 80 years) and -2.67 ± 2.91 D (range: -14.13 to +5.75 D), respectively. Cutoff limits for normal interocular nerve fibre layer thickness differences (2.5th and 97.5th percentiles of normative data) in the global area and in the superior, nasal, inferior and temporal quadrants were 9.5, 23.0, 15.6, 20.0 and 22.6 μm, respectively. Mean interocular retinal nerve fibre layer thickness differences in global area and in superior, nasal, inferior and temporal quadrants were 0.7 (p fibre layer thickness differences were not significantly correlated with age or refractive error (average of right and left eyes, both p > 0.05). Significant interocular differences in peripapillary retinal nerve fibre layer thickness exist in healthy eyes, particularly in the superior quadrant. This finding should be considered when comparing retinal nerve fibre layer thickness between right and left eyes. © 2014 The Authors. Clinical and Experimental Optometry © 2014 Optometrists Association Australia.

  13. Human Heart Pulse Wave Responses Measured Simultaneously at Several Sensor Placements by Two MR-Compatible Fibre Optic Methods

    Directory of Open Access Journals (Sweden)

    Teemu Myllylä

    2012-01-01

    Full Text Available This paper presents experimental measurements conducted using two noninvasive fibre optic methods for detecting heart pulse waves in the human body. Both methods can be used in conjunction with magnetic resonance imaging (MRI. For comparison, the paper also performs an MRI-compatible electrocardiogram (ECG measurement. By the simultaneous use of different measurement methods, the propagation of pressure waves generated by each heart pulse can be sensed extensively in different areas of the human body and at different depths, for example, on the chest and forehead and at the fingertip. An accurate determination of a pulse wave allows calculating the pulse transit time (PTT of a particular heart pulse in different parts of the human body. This result can then be used to estimate the pulse wave velocity of blood flow in different places. Both measurement methods are realized using magnetic resonance-compatible fibres, which makes the methods applicable to the MRI environment. One of the developed sensors is an extraordinary accelerometer sensor, while the other one is a more common sensor based on photoplethysmography. All measurements, involving several test patients, were performed both inside and outside an MRI room. Measurements inside the MRI room were conducted using a 3-Tesla strength closed MRI scanner in the Department of Diagnostic Radiology at the Oulu University Hospital.

  14. First-time demonstration of measuring concrete prestress levels with metal packaged fibre optic sensors

    Science.gov (United States)

    Mckeeman, I.; Fusiek, G.; Perry, M.; Johnston, M.; Saafi, M.; Niewczas, P.; Walsh, M.; Khan, S.

    2016-09-01

    In this work we present the first large-scale demonstration of metal packaged fibre Bragg grating sensors developed to monitor prestress levels in prestressed concrete. To validate the technology, strain and temperature sensors were mounted on steel prestressing strands in concrete beams and stressed up to 60% of the ultimate tensile strength of the strand. We discuss the methods and calibration procedures used to fabricate and attach the temperature and strain sensors. The use of induction brazing for packaging the fibre Bragg gratings and welding the sensors to prestressing strands eliminates the use of epoxy, making the technique suitable for high-stress monitoring in an irradiated, harsh industrial environment. Initial results based on the first week of data after stressing the beams show the strain sensors are able to monitor prestress levels in ambient conditions.

  15. Retinal nerve fibre layer thickness measured by Spectralis spectral-domain optical coherence tomography: The Beijing Eye Study.

    Science.gov (United States)

    Zhao, Liang; Wang, Yaxing; Chen, Chang X; Xu, Liang; Jonas, Jost B

    2014-02-01

    The aim of this study was to measure retinal nerve fibre layer thickness (RNFLT) and its associated factors in a population-based setting. The population-based Beijing Eye Study 2011 included 3468 individuals. The study participants underwent spectral-domain optical coherence tomography (Spectralis(®) ; Spectralis OCT)-assisted measurement of the RNFLT. For this study, exclusion criteria were glaucoma, pseudoexfoliation, best-corrected visual acuity of >0.5 logMAR, macular diseases, previous ocular surgery and known neurological diseases. The only inclusion criterion was an age of 50+ years. The inclusion criteria were fulfilled by 2548 participants. Mean RNFLT was 102 ± 11 μm. RNFLT was significantly (p optic disc size (p optic disc, larger rim, hyperopic refractive error, larger parapapillary beta zone and thicker subfoveal choroidal thickness. Independent of age and refractive error, the RNFL was thickest temporal inferiorly and thinnest temporally and nasally. © 2013 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  16. Fibre Bragg grating based accelerometer with extended bandwidth

    International Nuclear Information System (INIS)

    Basumallick, Nandini; Biswas, Palas; Dasgupta, Kamal; Bandyopadhyay, Somnath; Chakraborty, Rajib; Chakraborty, Sushanta

    2016-01-01

    We have shown experimentally that the operable bandwidth of a fibre Bragg grating (FBG) based accelerometer can be extended significantly, without compromising its sensitivity, using a post-signal processing technique which involves frequency domain weighting. It has been demonstrated that using the above technique acceleration can be correctly interpreted even when the operating frequency encroaches on the region where the frequency response of the sensor is non-uniform. Two different excitation signals, which we often encounter in structural health monitoring applications, e.g. (i) a signal composed of multi-frequency components and (ii) a sinusoidal excitation with a frequency sweep, have been considered in our experiment. The results obtained have been compared with a piezo accelerometer. (paper)

  17. Photonic Crystal Fibre SERS Sensors Based on Silver Nanoparticle Colloid

    International Nuclear Information System (INIS)

    Zhi-Guo, Xie; Yong-Hua, Lu; Pei, Wang; Kai-Qun, Lin; Jie, Yan; Hai, Ming

    2008-01-01

    A photonic crystal fibre (PCF) surface enhanced Raman scattering (SERS) sensor is developed based on silver nanoparticle colloid. Analyte solution and silver nanoparticles are injected into the air holes of PCF by a simple modified syringe to overcome mass-transport constraints, allowing more silver nanoparticles involved in SERS activity. This sensor offers significant benefit over the conventional SERS sensor with high flexibility, easy manufacture. We demonstrate the detection of 4-mercaptobenzoic acid (4-MBA) molecules with the injecting way and the common dipping measurement. The injecting way shows obviously better results than the dipping one. Theoretical analysis indicates that this PCF SERS substrate offers enhancement of about 7 orders of magnitude in SERS active area

  18. Micro and Nanostructured Materials for the Development of Optical Fibre Sensors

    Directory of Open Access Journals (Sweden)

    Cesar Elosua

    2017-10-01

    Full Text Available The measurement of chemical and biomedical parameters can take advantage of the features exclusively offered by optical fibre: passive nature, electromagnetic immunity and chemical stability are some of the most relevant ones. The small dimensions of the fibre generally require that the sensing material be loaded into a supporting matrix whose morphology is adjusted at a nanometric scale. Thanks to the advances in nanotechnology new deposition methods have been developed: they allow reagents from different chemical nature to be embedded into films with a thickness always below a few microns that also show a relevant aspect ratio to ensure a high transduction interface. This review reveals some of the main techniques that are currently been employed to develop this kind of sensors, describing in detail both the resulting supporting matrices as well as the sensing materials used. The main objective is to offer a general view of the state of the art to expose the main challenges and chances that this technology is facing currently.

  19. Bidirectional wavelength-division multiplexing transmission over installed fibre using a simplified optical coherent access transceiver.

    Science.gov (United States)

    Erkılınç, M S; Lavery, D; Shi, K; Thomsen, B C; Killey, R I; Savory, S J; Bayvel, P

    2017-10-19

    High-speed broadband services require optical fibres in access networks, in which multiple subscribers are connected to service providers, to satisfy the continuously growing bandwidth demand. The primitive signaling scheme used in access networks enables the use of low-cost equipment but diminishes the bandwidth available to end-users. Thus, current technology will be unable to support future broadband demands. Coherent communication systems offer significantly improved power- and bandwidth-efficiency, but require fundamental simplifications to become economically viable for access networks. Here, we demonstrate a promising simplified coherent receiver exhibiting a robust performance against polarisation fluctuations over an installed fibre network. It enables the realisation of high-order modulation formats and offers high sensitivities, achieving a four-fold increase in the supported number of subscribers and approximately doubling the transmission distance compared to the recently standardized access technology. The proposed solution indicates that digital coherent technology can be feasible and transform the access networks, enabling ubiquitous new services and applications with uncontended, multi-gigabits/user broadband connections.

  20. Micro and Nanostructured Materials for the Development of Optical Fibre Sensors.

    Science.gov (United States)

    Elosua, Cesar; Arregui, Francisco Javier; Villar, Ignacio Del; Ruiz-Zamarreño, Carlos; Corres, Jesus M; Bariain, Candido; Goicoechea, Javier; Hernaez, Miguel; Rivero, Pedro J; Socorro, Abian B; Urrutia, Aitor; Sanchez, Pedro; Zubiate, Pablo; Lopez-Torres, Diego; Acha, Nerea De; Ascorbe, Joaquin; Ozcariz, Aritz; Matias, Ignacio R

    2017-10-11

    The measurement of chemical and biomedical parameters can take advantage of the features exclusively offered by optical fibre: passive nature, electromagnetic immunity and chemical stability are some of the most relevant ones. The small dimensions of the fibre generally require that the sensing material be loaded into a supporting matrix whose morphology is adjusted at a nanometric scale. Thanks to the advances in nanotechnology new deposition methods have been developed: they allow reagents from different chemical nature to be embedded into films with a thickness always below a few microns that also show a relevant aspect ratio to ensure a high transduction interface. This review reveals some of the main techniques that are currently been employed to develop this kind of sensors, describing in detail both the resulting supporting matrices as well as the sensing materials used. The main objective is to offer a general view of the state of the art to expose the main challenges and chances that this technology is facing currently.

  1. Single-Mode Propagation in Optical Waveguides and Fibres: A Critical Review of its Treatment in Physics Textbooks

    Science.gov (United States)

    Ruddock, Ivan S.

    2009-01-01

    The derivation and description of the modes in optical waveguides and fibres are reviewed. The version frequently found in undergraduate textbooks is shown to be incorrect and misleading due to the assumption of an axial ray of light corresponding to the lowest order mode. It is pointed out that even the lowest order must still be represented in…

  2. Sub-micrometre accurate free-form optics by three-dimensional printing on single-mode fibres

    Science.gov (United States)

    Gissibl, Timo; Thiele, Simon; Herkommer, Alois; Giessen, Harald

    2016-01-01

    Micro-optics are widely used in numerous applications, such as beam shaping, collimation, focusing and imaging. We use femtosecond 3D printing to manufacture free-form micro-optical elements. Our method gives sub-micrometre accuracy so that direct manufacturing even on single-mode fibres is possible. We demonstrate the potential of our method by writing different collimation optics, toric lenses, free-form surfaces with polynomials of up to 10th order for intensity beam shaping, as well as chiral photonic crystals for circular polarization filtering, all aligned onto the core of the single-mode fibres. We determine the accuracy of our optics by analysing the output patterns as well as interferometrically characterizing the surfaces. We find excellent agreement with numerical calculations. 3D printing of microoptics can achieve sufficient performance that will allow for rapid prototyping and production of beam-shaping and imaging devices. PMID:27339700

  3. Sub-micrometre accurate free-form optics by three-dimensional printing on single-mode fibres

    Science.gov (United States)

    Gissibl, Timo; Thiele, Simon; Herkommer, Alois; Giessen, Harald

    2016-06-01

    Micro-optics are widely used in numerous applications, such as beam shaping, collimation, focusing and imaging. We use femtosecond 3D printing to manufacture free-form micro-optical elements. Our method gives sub-micrometre accuracy so that direct manufacturing even on single-mode fibres is possible. We demonstrate the potential of our method by writing different collimation optics, toric lenses, free-form surfaces with polynomials of up to 10th order for intensity beam shaping, as well as chiral photonic crystals for circular polarization filtering, all aligned onto the core of the single-mode fibres. We determine the accuracy of our optics by analysing the output patterns as well as interferometrically characterizing the surfaces. We find excellent agreement with numerical calculations. 3D printing of microoptics can achieve sufficient performance that will allow for rapid prototyping and production of beam-shaping and imaging devices.

  4. Tunable polarisation-maintaining filter based on liquid crystal photonic bandgap fibre

    DEFF Research Database (Denmark)

    Scolari, Lara; Olausson, Christina Bjarnal Thulin; Weirich, Johannes

    2008-01-01

    A tunable and polarisation-maintaining all-in-fibre filter based on a liquid crystal photonic bandgap fibre is demonstrated. Its polarisation extinction ratio reaches 14 dB at 1550 nm wavelength. Its spectral tunability range spans over 250 nm in the temperature range 30–70°C. The measured...

  5. Subpicosecond pulse propagation in optical fibres with transverse and longitudinal inhomogeneities

    CERN Document Server

    Bisyarin, M A

    2003-01-01

    Short optical pulse propagation is investigated in the light guide characterized with a strong dependence of the fibre material refractive index on the radial coordinate and a weak dependence on the longitudinal coordinate, with a weak spatial bending of the light guide axis being allowed as well. A three-dimensional nonlinear wave equation used in modeling the process is solved asymptotically with respect to a small parameter setting the order of magnitude of the pulse amplitude. A relationship between the propagating modes and the eigenvalues and eigenfunctions of a singular Sturm-Liouville problem is elucidated. The pulse propagation is shown to be three-scale: the high-frequency carrier is modulated with the envelope which evolves in a two-scale manner and is described with a nonlinear Schroedinger equation with coefficients depending on the longitudinal coordinate. For several types of the transverse and longitudinal inhomogeneities, expressions through elementary functions are obtained for the transvers...

  6. Oscillations in the interactions among multiple solitons in an optical fibre

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Wen-Qiang; Gao, Yi-Tian; Zhao, Chen; Feng, Yu-Jie; Su, Chuan-Qi [Beijing University of Aeronautics and Astronautics (China). Ministry of Education Key Laboratory of Fluid Mechanics; Beijing University of Aeronautics and Astronautics (China). National Laboratory for Computational Fluid Dynamics

    2016-07-01

    In this article, under the investigation on the interactions among multiple solitons for an eighth-order nonlinear Schroedinger equation in an optical fibre, oscillations in the interaction zones are observed theoretically. With different coefficients of the operators in this equation, we find that (1) the oscillations in the solitonic interaction zones have different forms with different spectral parameters of this equation; (2) the oscillations in the interactions among the multiple solitons are affected by the choice of spectral parameters, the dispersive effects and nonlinearity of the eighth-order operator; (3) the second-, fifth-, sixth-, and seventh-order operators restrain oscillations in the solitonic interaction zones and the higher-order operators have stronger attenuated effects than the lower ones, while the third- and fourth-order operators stimulate and extend the scope of oscillations.

  7. Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications.

    Science.gov (United States)

    Di Sante, Raffaella

    2015-07-30

    In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS) have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques.

  8. Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications

    Directory of Open Access Journals (Sweden)

    Raffaella Di Sante

    2015-07-01

    Full Text Available In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques.

  9. Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications

    Science.gov (United States)

    Di Sante, Raffaella

    2015-01-01

    In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS) have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques. PMID:26263987

  10. Direct Spectroscopy in Hollow Optical with Fiber-Based Optical Frequency Combs

    Science.gov (United States)

    2015-07-09

    Perrella, P. S. Light, F. Benabid, and A. N. Luiten, "Towards a compact optical fibre clock," in Precision Electromagnetic Measurements (CPEM), 2010...AFRL-OSR-VA-TR-2015-0184 DIRECT SPECTROSCOPY IN HOLLOW OPTICAL WITH FIBER-BASED OPTICAL FREQUENCY COMBS Kristan Corwin KANSAS STATE UNIVERSITY Final...Performance 3.  DATES COVERED (From - To)      01-06-2011 to 31-05-2015 4.  TITLE AND SUBTITLE DIRECT SPECTROSCOPY IN HOLLOW OPTICAL WITH FIBER-BASED

  11. Atomic force microscopy for the determination of refractive index profiles of optical fibres and waveguides: a quantitative study

    International Nuclear Information System (INIS)

    Huntington, S.T.; Mulvaney, P.; Roberts, K.A.

    1997-01-01

    The use of preferential etching and atomic force microscopy to measure refractive index profiles of optical fibres is investigated. Both the etch rate and the position of lateral features are shown to be independent of etch time. An elliptical core fibre has been studied and the resultant profile found to be in qualitative agreement with the preform index profile. It is shown, however, that the ellipticity of the core has changed during the drawing process. The method has been extended to fluorine and germanium doped planar waveguides and the results correlated with the fabrication process

  12. Experimental and numerical study on refractive index sensors based on fibre Bragg gratings inscribed in multimode fibre

    Science.gov (United States)

    Filipe Kuhne, Jean; Rocha, Ana Maria; de Oliveira, Valmir; José Kalinowski, Hypolito; Canute Kamikawachi, Ricardo

    2018-02-01

    In this work is reported the experimental and numerical results of the refractive index response of etched fibre Bragg gratings written in a graded index multimode fibre. The responses of the modes coupled by the grating inscribed in a multimode fibre are compared with the mode coupled by a grating inscribed in single mode fibre. The results of this study show that the refractive index sensitivity and the dynamical range of etched fibre Bragg gratings written in multimode fibres are higher than the ones verified in single-mode fibres. The determination of oil-biodiesel blend concentrations are also compared as an example of practical applications. It is shown that a greater core diameter of the multimode fibre enables the Bragg gratings to exhibit enhanced sensitivity without requiring further fibre diameter reduction.

  13. Predictive modelling-based design and experiments for synthesis and spinning of bioinspired silk fibres

    Science.gov (United States)

    Gronau, Greta; Jacobsen, Matthew M.; Huang, Wenwen; Rizzo, Daniel J.; Li, David; Staii, Cristian; Pugno, Nicola M.; Wong, Joyce Y.; Kaplan, David L.; Buehler, Markus J.

    2016-01-01

    Scalable computational modelling tools are required to guide the rational design of complex hierarchical materials with predictable functions. Here, we utilize mesoscopic modelling, integrated with genetic block copolymer synthesis and bioinspired spinning process, to demonstrate de novo materials design that incorporates chemistry, processing and material characterization. We find that intermediate hydrophobic/hydrophilic block ratios observed in natural spider silks and longer chain lengths lead to outstanding silk fibre formation. This design by nature is based on the optimal combination of protein solubility, self-assembled aggregate size and polymer network topology. The original homogeneous network structure becomes heterogeneous after spinning, enhancing the anisotropic network connectivity along the shear flow direction. Extending beyond the classical polymer theory, with insights from the percolation network model, we illustrate the direct proportionality between network conductance and fibre Young's modulus. This integrated approach provides a general path towards de novo functional network materials with enhanced mechanical properties and beyond (optical, electrical or thermal) as we have experimentally verified. PMID:26017575

  14. Predictive modelling-based design and experiments for synthesis and spinning of bioinspired silk fibres.

    Science.gov (United States)

    Lin, Shangchao; Ryu, Seunghwa; Tokareva, Olena; Gronau, Greta; Jacobsen, Matthew M; Huang, Wenwen; Rizzo, Daniel J; Li, David; Staii, Cristian; Pugno, Nicola M; Wong, Joyce Y; Kaplan, David L; Buehler, Markus J

    2015-05-28

    Scalable computational modelling tools are required to guide the rational design of complex hierarchical materials with predictable functions. Here, we utilize mesoscopic modelling, integrated with genetic block copolymer synthesis and bioinspired spinning process, to demonstrate de novo materials design that incorporates chemistry, processing and material characterization. We find that intermediate hydrophobic/hydrophilic block ratios observed in natural spider silks and longer chain lengths lead to outstanding silk fibre formation. This design by nature is based on the optimal combination of protein solubility, self-assembled aggregate size and polymer network topology. The original homogeneous network structure becomes heterogeneous after spinning, enhancing the anisotropic network connectivity along the shear flow direction. Extending beyond the classical polymer theory, with insights from the percolation network model, we illustrate the direct proportionality between network conductance and fibre Young's modulus. This integrated approach provides a general path towards de novo functional network materials with enhanced mechanical properties and beyond (optical, electrical or thermal) as we have experimentally verified.

  15. Single-mode fibre coupler as refractometer sensor

    Indian Academy of Sciences (India)

    We report a simple, non-intrusive fibre-optic refractometer sensor for measuring the refractive index of liquid and optically transparent solid medium. Sensing principle of the proposed sensor is based on monitoring the back-reflected light signal through the second input port of a 2 × 1 single-mode fibre coupler when light ...

  16. New absorbent material acoustic based on kenaf’s fibre

    Directory of Open Access Journals (Sweden)

    Ramis, J.

    2010-09-01

    Full Text Available Acoustic Standards in the building are responsible for, companies and individuals, propose new acoustic materials for the sound isolation. This paper presents a new sound-absorbent material, it is based on natural fibres, particularly fibres of kenaf. It also proposes an empirical model for this material, this models depends on the frequency. There are accepted models from the scientific community about mineral wool, glass wool, rock wool, foam or polyester fibre. Several of these models are empirical. They are obtained from the equation adjustments about the acoustic impedance and propagation constant behaviour, depending upon the flow resistivity, fibre’s diameter and density. There are even standards like UNE-EN 12354-6 where these models are accepted under certain limitations like the fundamental basis as in the materials’ acoustics behaviour prediction. From the various tests conducted in the laboratory, empirical equations are proposed for this new acoustic material. In addition, there has been a first approach to validate this model in combination with a micro-structural model, based on the steps taken by Bies-Hansen (1, which allows us to obtain the value of the resistance to flow.

    El carácter marcadamente prestacional de las normativas acústicas en la edificación abre el camino a la propuesta, por parte de empresas y particulares, de nuevos materiales acústicos susceptibles de ser utilizados en el ámbito de la acústica de la edificación. Éste es el caso que nos ocupa en el presente trabajo en el que se presenta un nuevo material acústico absorbente basado en fibras vegetales, concretamente el kenaf. Además se propone un modelo empírico de modelización del comportamiento absorbente de varias composiciones de este material en función de la frecuencia. Existen modelos de diferentes lanas minerales, lanas de roca, lanas de vidrio, espumas o lanas de poliéster. Algunos de estos modelos —llamados empíricos— se

  17. An Innovative Context-Based Module to Introduce Students to the Optical Properties of Materials

    Science.gov (United States)

    Testa, I.; Lombardi, S.; Monroy, G.; Sassi, E.

    2011-01-01

    A context-based module to introduce secondary school students to the study of the optical properties of materials and geometric optics is presented. The module implements an innovative teaching approach in which the behaviour of the chosen application, in this article, the optical fibre, is iteratively explored and modelled by means of a…

  18. The relationship between the optical density of cataract and its influence on retinal nerve fibre layer thickness measured with spectral domain optical coherence tomography

    NARCIS (Netherlands)

    Kok, Pauline H. B.; van den Berg, Thomas J. T. P.; van Dijk, Hille W.; Stehouwer, Marilette; van der Meulen, Ivanka J. E.; Mourits, Maarten P.; Verbraak, Frank D.

    2013-01-01

    The purpose of this study was to model the influence of cataract on Spectral Domain Optical Coherence Tomography (SDOCT) image quality and Retinal Nerve Fibre Layer (RNFL) thickness measurements. SDOCT images, made with two different devices (3DOCT-1000, Topcon and Cirrus HD-OCT), before and after

  19. Comparative study of the retinal nerve fibre layer thickness performed with optical coherence tomography and GDx scanning laser polarimetry in patients with primary open-angle glaucoma.

    Science.gov (United States)

    Wasyluk, Jaromir T; Jankowska-Lech, Irmina; Terelak-Borys, Barbara; Grabska-Liberek, Iwona

    2012-03-01

    We compared the parameters of retinal nerve fibre layer in patients with advanced glaucoma with the use of different OCT (Optical Coherence Tomograph) devices in relation to analogical measurements performed with GDx VCC (Nerve Fiber Analyzer with Variable Corneal Compensation) scanning laser polarimetry. Study subjects had advanced primary open-angle glaucoma, previously treated conservatively, diagnosed and confirmed by additional examinations (visual field, ophthalmoscopy of optic nerve, gonioscopy), A total of 10 patients were enrolled (9 women and 1 man), aged 18-70 years of age. Nineteen eyes with advanced glaucomatous neuropathy were examined. 1) Performing a threshold perimetry Octopus, G2 strategy and ophthalmoscopy of optic nerve to confirm the presence of advanced primary open-angle glaucoma; 2) performing a GDx VCC scanning laser polarimetry of retinal nerve fibre layer; 3) measuring the retinal nerve fibre layer thickness with 3 different optical coherence tomographs. The parameters of the retinal nerve fibre layer thickness are highly correlated between the GDx and OCT Stratus and 3D OCT-1000 devices in mean retinal nerve fibre layer thickness, retinal nerve fibre layer thickness in the upper sector, and correlation of NFI (GDx) with mean retinal nerve fibre layer thickness in OCT examinations. Absolute values of the retinal nerve fibre layer thickness (measured in µm) differ significantly between GDx and all OCT devices. Examination with OCT devices is a sensitive diagnostic method of glaucoma, with good correlation with the results of GDx scanning laser polarimetry of the patients.

  20. Retinal nerve fibre layer thickness measurements in normal Indian population by optical coherence tomography

    Directory of Open Access Journals (Sweden)

    Ramakrishnan R

    2006-01-01

    Full Text Available Purpose: To obtain retinal nerve fibre layer thickness measurements by optical coherence tomography (OCT in normal Indian population. Materials and Methods: Total of 118 randomly selected eyes of 118 normal Indian subjects of both sex and various age groups underwent retinal nerve fiber layer thickness analysis by Stratus OCT 3000 V 4.0.1. The results were evaluated and compared to determine the normal retinal nerve fiber layer thickness measurements and its variations with sex and age. Results: Mean + standard deviation retinal nerve fiber layer thickness for various quadrants of superior, inferior, nasal, temporal, and along the entire circumference around the optic nerve head were 138.2 + 21.74, 129.1 + 25.67, 85.71 + 21, 66.38 + 17.37, and 104.8 + 38.81 µm, respectively. There was no significant difference in the measurements between males and females, and no significant correlation with respect to age. Conclusion: Our results provide the normal retinal nerve fiber layer thickness measurements and its variations with age and sex in Indian population.

  1. Determining the moisture content in concrete with a fibre optic Mach-Zehnder interferometer: a feasibility study

    Science.gov (United States)

    Swart, Pieter L.; Naude, Riaan; Lacquet, Beatrys M.

    2001-07-01

    This paper proposes and demonstrates the use of a fibre optic Mach-Zehnder interferometer to determine the average bulk moisture content of concrete. The principle of operation is based on the moisture dependence of the propagation velocity of shock waves in the concrete. A spring-loaded gun with stainless steel balls of various diameters created the shock waves. The time delay of the shock waves between the two arms of the interferometer embedded in an experimental concrete block could be determined from the autocorrelation function of the interference signal obtained at the optical detector. The average velocity at room temperature measured in dry concrete was 3.54±0.34 km s-1, and for moist concrete it was 5.00±0.45 km s-1. These values indicate that the discrimination between moist and dry concrete is large enough, and the standard deviations in the measurements small enough, to make this a feasible approach to determine the moisture content in concrete.

  2. Molecular absorption measurements with an optical fibre coupled array of ultra-violet light-emitting diodes.

    Science.gov (United States)

    Bui, Duy Anh; Kraiczek, Karsten G; Hauser, Peter C

    2017-09-15

    A photometric detector based on eight different light-emitting diodes covering the ultraviolet range from 255 nm to 350 nm is described. These are coupled with fused silica optical fibres to a conventional cuvette with 1 cm optical path length or to a low volume flow through cell for detection in high-performance liquid chromatography. Photodiodes are employed for the measurement of the transmitted intensity as well as of a reference signal and the photocurrents are processed with a log-ratio amplifier to obtain a voltage proportional to absorbance values. The wavelength desired for the measurement at hand is selected by electronically switching on the requisite light-emitting diode. The detector was found to have a low noise level of 80 μAU. In batch-wise measurements as well as in detection for high-performance liquid chromatography dynamic ranges of 2-3 orders of magnitude were possible. Reproducibilities in peak areas for the latter application were better than 1%. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. An Optical System to Monitor the Displacement Field of Glass-fibre Posts Subjected to Thermal Loading.

    Science.gov (United States)

    Corsalini, Massimo; Pettini, Francesco; Di Venere, Daniela; Ballini, Andrea; Chiatante, Giuseppe; Lamberti, Luciano; Pappalettere, Carmine; Fiorentino, Michele; Uva, Antonio E; Monno, Giuseppe; Boccaccio, Antonio

    2016-01-01

    Endocanalar posts are necessary to build up and retain coronal restorations but they do not reinforce dental roots. It was observed that the dislodgement of post-retained restorations commonly occurs after several years of function and long-term retention may be influenced by various factors such as temperature changes. Temperature changes, in fact, produce micrometric deformations of post and surrounding tissues/materials that may generate high stress concentrations at the interface thus leading to failure. In this study we present an optical system based on the projection moiré technique that has been utilized to monitor the displacement field of endocanalar glass-fibre posts subjected to temperature changes. Measurements were performed on forty samples and the average displacement values registered at the apical and middle region were determined for six different temperature levels. A total of 480 displacement measurements was hence performed. The values of the standard deviation computed for each of the tested temperatures over the forty samples appear reasonably small which proves the robustness and the reliability of the proposed optical technique. The possible implications for the use of the system in the applicative context were discussed.

  4. Impact of amplitude jitter and signal-to-noise ratio on the nonlinear spectral compression in optical fibres

    Science.gov (United States)

    Boscolo, Sonia; Fatome, Julien; Finot, Christophe

    2017-04-01

    We numerically study the effects of amplitude fluctuations and signal-to-noise ratio degradation of the seed pulses on the spectral compression process arising from nonlinear propagation in an optical fibre. The unveiled quite good stability of the process against these pulse degradation factors is assessed in the context of optical regeneration of intensity-modulated signals, by combining nonlinear spectral compression with centered bandpass optical filtering. The results show that the proposed nonlinear processing scheme indeed achieves mitigation of the signal's amplitude noise. However, in the presence of a jitter of the temporal duration of the pulses, the performance of the device deteriorates. © 2016 Elsevier

  5. Optical fibres sensor based in the intensity switch of a linear laser with two Bragg gratings; Sensor de fibra optica basado en el salto de intensidad de un laser lineal con dos rejillas de Bragg

    Energy Technology Data Exchange (ETDEWEB)

    Basurto P, M.A.; Kuzin, E.A.; Archundia B, C.; Marroquin, E.; May A, M.; Cerecedo N, H.H.; Sanchez M, J.J. [Departamento de Fotonica y Fisica Optica, Instituto Nacional de Astrofisica, Optica y Electronica (INAOE). Apartado Postal 51 y 216, 72000 Puebla (Mexico); Tentori S, D.; Marquez B, I.; Shliagin, M.; Miridonov, S. [Centro de Investigacion CESE (Mexico)

    2000-07-01

    In this work we propose a new configuration for an optical fiber temperature sensor, based on a linear type Er-doped fiber laser. The laser cavity consists of an Er-doped fiber and two identical Bragg gratings at the fiber ends (working as reflectors). Temperature changes are detected by measuring, through one of the gratings, the intensity variations atthe system's output. When the temperature of one of the Bragg gratings is modified, a wavelength shift of its spectral reflectivity is observed. Hence, the laser emission intensity of the system is modified. We present experimental results of the intensity switch observed when the temperature difference between the gratings detunes their spectral reflectance. Making use of this effect it is possible to develop limit comparators to bound the temperature range for the object under supervision. This limiting work can be performed with a high sensitivity using a very simple interrogation procedure. (Author)

  6. Measurement of temperature profiles in process-applications using fibre-optical methods; Prozessgeeignete Temperaturprofilmessungen mit faseroptischen Methoden

    Energy Technology Data Exchange (ETDEWEB)

    Seefeld, P. [Endress und Hauser Wetzer GmbH und Co.KG, Nesselwang (Germany)

    2008-07-01

    Fibre-optical temperature measuring methods are offering an approach to detect temperature profiles. According to the NAMUR-Technology-Roadmap the detection of temperature profiles is representing an increased benefit. Intrinsic fibre-optical temperature measuring techniques are presented, known as OTDRmethod (Optical tine domain reflectometry) facilitating a distributed temperature measurement method that allows a resolution in the range of decimetres. For the purpose of such applications a suitable photoncounting device comprises mechanical robust fibre-optical components, 3 db Coupler, referenced Laser- Diode, Y-Coupler with integrated band-filter and APD (Avalanche Diode) used in a detection module. A VHDL-coded FBGA-board provides a basic control-device for - a Laser-Driver to generate adjustable exiting-pulses in the range of nanoseconds at rates up to 100 kHz. - a Photon-Counting module with a minimum opening width in the range of one nanosecond - that permits the co-addition of the photon-counts derived from the spectral resolved Stokes and Anti-Stokes band. (orig.)

  7. Control over the resonance wavelength of fibre Bragg gratings using resistive coatings based on single-wall carbon nanotubes

    Science.gov (United States)

    Gladush, Yu. G.; Medvedkov, O. I.; Vasil'ev, S. A.; Kopylova, D. S.; Yakovlev, V. Ya.; Nasibulin, A. G.

    2016-10-01

    We demonstrate that a thin resistive coating based on single-wall carbon nanotubes applied to the lateral surface of an optical fibre allows it to be uniformly heated up to a temperature of ∼ 400 \\circ{\\text{C}} without damage to the coating. Using a fibre Bragg grating (FBG) as an example, we assess the efficiency of resonance wavelength thermal tuning and examine frequency characteristics that can be achieved using such coating. In particular, we show that the resonance wavelength of the FBG can be tuned over 3.2 {\\text{nm}} with an efficiency of 8.7 {\\text{nm}} {\\text{W}}-1 and time constant of ∼ 0.4 {\\text{s}}.

  8. Experimental Studies on Punching Shear and Impact Resistance of Steel Fibre Reinforced Slag Based Geopolymer Concrete

    Directory of Open Access Journals (Sweden)

    Srinivasan Karunanithi

    2017-01-01

    Full Text Available The study was focused on slag based geopolymer concrete with the addition of steel fibre. The slag based geopolymer concrete was under shear load and sudden impact load to determine its response. The punching shear represents the load dissipation of the material and the energy absorption capacity of the geopolymer concrete to impact load. The various percentage of steel fibre in the slag based geopolymer concrete was 0.5%, 1.0%, and 1.5%. Overall the dosage 0.5% of steel fibre reinforced slag based geopolymer shows better results with a punching shear of 224 kN and 1.0% of steel fibre incorporated geopolymer concrete had the better energy absorption capacity with 3774.40 N·m for first crack toughness and 4123.88 N·m for ultimate failure toughness.

  9. Bending Strength and Fracture Investigations of Cu Based Composite Materials Strengthened with δ-Alumina Fibres

    Directory of Open Access Journals (Sweden)

    Kaczmar J.W.

    2013-06-01

    Full Text Available Bending strength, thermal and electric conductivity and microstructure examinations of Cu based composite materials reinforced with Saffil alumina fibres are presented. Materials were produced by squeeze casting method applying the designed device and specially elaborated production parameters. Applying infiltration pressure of 90MPa and suitable temperature parameters provided manufacturing of copper based composite materials strengthened with Saffil alumina fibres characterized by the low rest porosity and good fibre-matrix interface. Three point bending tests at temperatures of 25, 100 and 300ºC were performed on specimens reinforced with 10, 15 and 20% of Saffil fibres. Introduced reinforcement effected on the relatively high bending strengths at elevated temperatures. In relation to unreinforced Cu casting strength of composite material Cu - 15vol.% Saffil fibres increase by about 25%, whereas at the highest applied test temperature of 300oC the improvement was almost 100%. Fibres by strengthening of the copper matrix and by transferring loads from the matrix reduce its plastic deformation and hinder the micro-crack developed during bending tests. Decreasing of thermal and electrical conductivity of Cu after incorporating fibres in the matrix are relatively small and these properties can be acceptable for electric and thermal applications.

  10. Detection of macular ganglion cell loss in preperimetric glaucoma patients with localized retinal nerve fibre defects by spectral-domain optical coherence tomography.

    Science.gov (United States)

    Na, Jung Hwa; Lee, Kyoungsub; Lee, Jong Rak; Baek, Seunghee; Yoo, Sung Jun; Kook, Michael S

    2013-12-01

    To evaluate and compare the utility of ganglion cell complex with peripapillary retinal nerve fibre layer and optic nerve head measurements for detection of localized defects in patients with preperimetric glaucoma using spectral-domain optical coherence tomography. Prospective study. Preperimetric glaucoma patients. A total of 105 eyes with preperimetric glaucoma and 68 age- and refractive error-matched control eyes were enrolled. The ability to detect localized retinal nerve fibre layer defects by RTVue-100 spectral-domain optical coherence tomography (Optovue, Inc., Fremont, CA, USA) was assessed calculating the areas under receiver operating characteristic curves. The ability to detect localized retinal nerve fibre layer defects by spectral-domain optical coherence tomography. Global volume loss and superior ganglion cell complex thickness showed the largest area under receiver operating characteristic curve values (both areas under receiver operating characteristic curves 0.84, P fibre layer thickness afforded the best diagnostic capability (area under receiver operating characteristic curve 0.89, P optic nerve head parameters, the horizontal cup:disc ratio yielded the highest area under receiver operating characteristic curve (0.85, P fibre layer, and optic nerve head) (P > 0.02). Ganglion cell complex thickness was significantly reduced in eyes with preperimetric glaucoma. Ganglion cell complex imaging using spectral-domain optical coherence tomography may be a useful ancillary modality for detection of early macular changes in glaucomatous eyes with localized retinal nerve fibre layer defects. © 2013 Royal Australian and New Zealand College of Ophthalmologists.

  11. Evaluating glaucomatous abnormality in peripapillary optical coherence tomography enface visualisation of the retinal nerve fibre layer reflectance.

    Science.gov (United States)

    Ashimatey, Bright S; King, Brett J; Burns, Stephen A; Swanson, William H

    2018-03-30

    Optical coherence tomography (OCT) enface visualisation of the retinal nerve fibre layer (RNFL) reflectance has been found to have some advantages over retinal thickness measures. However, it is not yet clear how abnormalities on enface images relate to findings of abnormalities from other clinical measures such as the circumpapillary retinal nerve fibre layer thickness (cRNFLT). We developed a technique to analyse the RNFL reflectance on the OCT enface images, and to investigate its relation with the cRNFLT. Spectralis (www.heidelbergengineering.com) OCT scans of the central retinal ±24° were analysed in the study eye of 31 controls and 33 patients, ages 61 (±9) and 69 (±8) years respectively. Enface slab-images were extracted at 16-24, 24-36, and 24-52 μm from the inner limiting membrane in the temporal raphe, perifoveal and disc regions respectively. Reflectance probability maps were generated for the patients based on the control data. Glaucomatous abnormality was defined on the slab-images when the slab-area with reflectance abnormality was greater than the 95th percentile, and on the cRNFLT when the thickness measure was less than the fifth percentile, of that found in controls. The fraction of slab-image showing reflectance abnormality was compared to cRNFLT in the patient group, using Spearman's rho. Agreement between the findings of abnormality based on cRNFLT and slab-image reflectance was assessed using Cohen's kappa. Slab-image and cRNFLT findings were in agreement for 26/33 eyes; four subjects showed cRNFLT abnormality but not slab-image abnormality, and three subjects showed slab-image abnormality but not cRNFLT abnormality. Spearman's rho found r s (31) = -0.82. The reflectance findings and cRNFLT findings were consistent in 27/33 for both the superior temporal (ST) and inferior temporal (IT) sectors, and Cohen's kappa found 0.53 and 0.61 respectively. The surface area of enface slab-images showing RNFL reflectance were strongly related to the c

  12. Evaluation of MidIR fibre optic reflectance: detection limit, reproducibility and binary mixture discrimination.

    Science.gov (United States)

    Sessa, Clarimma; Bagán, Héctor; García, José Francisco

    2013-11-01

    MidIR fibre optic reflectance (MidIR-FORS) is a promising analytical technique in the field of science conservation, especially because it is non-destructive. Another advantage of MidIR-FORS is that the obtained information is representative, as a large amount of spectral data can be collected. Although the technique has a high potential and is almost routinely applied, its quality parameters have not been thoroughly studied in the specific application of analysis of artistic materials. The objective of this study is to evaluate the instrumental capabilities of MidIR-FORS for the analysis of artwork materials in terms of detection limit, reproducibility, and mixture characterisation. The study has been focused on oil easel painting and several paints of known composition have been analysed. Paint layers include blue pigments not only because of their important role along art history, but also because their physical and spectroscopic characteristics allow a better evaluation of the MidIR-FORS capabilities. The results of the analysis indicate that MidIR-FORS supplies a signal affected by different factors, such as the optical, morphological and physical properties of the surface, in addition to the composition of materials analysed. Consequently, the detection limits established are relatively high for artistic objects (Prussian blue - PB 2.1-6.5%; Phthalocyanine blue - Pht 6.3-10.2%; synthetic Ultramarine blue - UM 12.1%) and may therefore lead to an incomplete description of the artwork. Reproducibility of the technique over time and across surface has been determined. The results show that the major sources of dispersion are the heterogeneity of the pigments distribution, physical features, and band shape distortions. The total dispersion is around 4% for the most intense bands (oil) and increases up to 26% when weak or overlapped bands are considered (PB, Pht, UM). The application of different pre-treatments (cutoff of fibres absorption, Savizky-Golay smoothing

  13. Evaluation of MidIR fibre optic reflectance: Detection limit, reproducibility and binary mixture discrimination

    Science.gov (United States)

    Sessa, Clarimma; Bagán, Héctor; García, José Francisco

    2013-11-01

    MidIR fibre optic reflectance (MidIR-FORS) is a promising analytical technique in the field of science conservation, especially because it is non-destructive. Another advantage of MidIR-FORS is that the obtained information is representative, as a large amount of spectral data can be collected. Although the technique has a high potential and is almost routinely applied, its quality parameters have not been thoroughly studied in the specific application of analysis of artistic materials. The objective of this study is to evaluate the instrumental capabilities of MidIR-FORS for the analysis of artwork materials in terms of detection limit, reproducibility, and mixture characterisation. The study has been focused on oil easel painting and several paints of known composition have been analysed. Paint layers include blue pigments not only because of their important role along art history, but also because their physical and spectroscopic characteristics allow a better evaluation of the MidIR-FORS capabilities. The results of the analysis indicate that MidIR-FORS supplies a signal affected by different factors, such as the optical, morphological and physical properties of the surface, in addition to the composition of materials analysed. Consequently, the detection limits established are relatively high for artistic objects (Prussian blue - PB 2.1-6.5%; Phthalocyanine blue - Pht 6.3-10.2%; synthetic Ultramarine blue - UM 12.1%) and may therefore lead to an incomplete description of the artwork. Reproducibility of the technique over time and across surface has been determined. The results show that the major sources of dispersion are the heterogeneity of the pigments distribution, physical features, and band shape distortions. The total dispersion is around 4% for the most intense bands (oil) and increases up to 26% when weak or overlapped bands are considered (PB, Pht, UM). The application of different pre-treatments (cutoff of fibres absorption, Savizky-Golay smoothing

  14. Products based on the mixes of fly ashes and fibre sludge (fibre-ashes) for road construction; Produkter baserade paa blandningar av flygaska och fiberslam (fiberaskor) foer vaegbyggande

    Energy Technology Data Exchange (ETDEWEB)

    Lahtinen, Pentti; Maijala Aino; Macsik, Josef

    2005-03-01

    The project has derived benefits from the earlier Finnish research and development as well as from the experience in the fibre-ash materials for geotechnical applications. The fly ashes used for the project have been taken from the same sources as the fly ashes for the earlier Vaermeforsk project 870: FACE. The project's objective was to develop construction materials based on mixtures of fibre sludge and fly ash for geotechnical applications, and for the final commercialisation of the fibre-ash materials. The mixtures are based on fly ashes from energy production (bark, peat and sludge used for incineration) and on kaolin containing fibre sludge from the paper industry. With help of laboratory tests the project has been searching for fibre ashes with excellent technical characteristics like good frost resistance combined with a good bearing capacity and resilience in geotechnical structures. The project's results has given additional knowledge about alternative road construction materials to construct technically good, sustainable and environmentally friendly roads and other constructions with lower costs than the conventional constructions. The results of laboratory tests have shown that this is possible. However, it has to be verified with help of field tests and pilot constructions. The first tasks of the project were to make choices of the appropriate fibre sludge and fly ashes for the project targets. The laboratory tests have been carried out in the geotechnical laboratory of Ramboll Finland Oy (earlier SCC Viatek Oy, SGT - later in the report SGT). After arrival of all test material in the laboratory the test programme started in order to find out the most optimal fibre-ash mixtures with or without any activator. The most potential mixtures were tested for their geotechnical long-term properties (mainly resistance against climatic load) and for their environmental risk potential. The results comprise of several technically, environmentally and

  15. Development and characterization of a hydrophobic treatment for jute fibres based on zinc oxide nanoparticles and a fatty acid

    Energy Technology Data Exchange (ETDEWEB)

    Arfaoui, M.A. [CTT Group, Saint-Hyacinthe (Canada); Department of Mechanical Engineering, Ecole de technologie supérieure, Montréal (Canada); Dolez, P.I., E-mail: pdolez@gcttg.com [CTT Group, Saint-Hyacinthe (Canada); Dubé, M.; David, É. [Department of Mechanical Engineering, Ecole de technologie supérieure, Montréal (Canada)

    2017-03-01

    Highlights: • A hydrophobic treatment based on zinc oxide nanoparticles and stearic acid was developed for recycled jute fibres. • The water contact angle was increased from 33° for the scoured fibre to 148° after the ZnO nanorod/stearic acid hydrothermal treatment. • The fibre thermal degradation temperature remained the same throughout the treatment at around 315 °C. • A reduction in the fibre breaking force of 32% was observed between the as-received and the ZnO nanorod/stearic acid treated fibres. - Abstract: This work aims at developing a hydrophobic treatment for jute fibres based on the grafting and growth of zinc oxide (ZnO) nanorods on the fibre surface. The first step consists in removing impurities from the fibre surface with a scouring treatment. In the second step, the jute fibres are coated with a layer of ZnO nanoseeds. A hydrothermal process is carried out as a third step to ensure a uniform growth of ZnO nanorods on the surface of the jute fibres. Finally, a hydrophobic treatment is performed on the ZnO nanorod-covered jute fibres using stearic acid (SA), i.e., a typical fatty acid. A large improvement in the fibre hydrophobicity was obtained without any negative effect on thermal stability and limited reduction in strength. Complementary measurements by scanning electron microscopy and X-ray diffraction were also performed and revealed a hexagonal system for the ZnO nanorods.

  16. Fast Bragg Grating Inscription in PMMA Polymer Optical Fibres: Impact of Thermal Pre-Treatment of Preforms

    Science.gov (United States)

    Marques, Carlos A. F.; Pospori, Andreas; Demirci, Gökhan; Çetinkaya, Onur; Gawdzik, Barbara; Antunes, Paulo; Bang, Ole; Mergo, Pawel; André, Paulo; Webb, David J.

    2017-01-01

    In this work, fibre Bragg gratings (FBGs) were inscribed in two different undoped poly- (methyl methacrylate) (PMMA) polymer optical fibres (POFs) using different types of UV lasers and their inscription times, temperature and strain sensitivities are investigated. The POF Bragg gratings (POFBGs) were inscribed using two UV lasers: a continuous UV HeCd @325 nm laser and a pulsed UV KrF @248 nm laser. Two PMMA POFs are used in which the primary and secondary preforms (during the two-step drawing process) have a different thermal treatment. The PMMA POFs drawn in which the primary or secondary preform is not specifically pre-treated need longer inscription time than the fibres drawn where both preforms have been pre-annealed at 80 °C for 2 weeks. Using both UV lasers, for the latter fibre much less inscription time is needed compared to another homemade POF. The properties of a POF fabricated with both preforms thermally well annealed are different from those in which just one preform step process is thermally treated, with the first POFs being much less sensitive to thermal treatment. The influence of annealing on the strain and temperature sensitivities of the fibres prior to FBG inscription is also discussed, where it is observed that the fibre produced from a two-step drawing process with well-defined pre-annealing of both preforms did not produce any significant difference in sensitivity. The results indicate the impact of preform thermal pre-treatment before the PMMA POFs drawing, which can be an essential characteristic in the view of developing POF sensors technology. PMID:28420216

  17. Fast Bragg Grating Inscription in PMMA Polymer Optical Fibres: Impact of Thermal Pre-Treatment of Preforms

    Directory of Open Access Journals (Sweden)

    Carlos A. F. Marques

    2017-04-01

    Full Text Available In this work, fibre Bragg gratings (FBGs were inscribed in two different undoped poly- (methyl methacrylate (PMMA polymer optical fibres (POFs using different types of UV lasers and their inscription times, temperature and strain sensitivities are investigated. The POF Bragg gratings (POFBGs were inscribed using two UV lasers: a continuous UV HeCd @325 nm laser and a pulsed UV KrF @248 nm laser. Two PMMA POFs are used in which the primary and secondary preforms (during the two-step drawing process have a different thermal treatment. The PMMA POFs drawn in which the primary or secondary preform is not specifically pre-treated need longer inscription time than the fibres drawn where both preforms have been pre-annealed at 80 °C for 2 weeks. Using both UV lasers, for the latter fibre much less inscription time is needed compared to another homemade POF. The properties of a POF fabricated with both preforms thermally well annealed are different from those in which just one preform step process is thermally treated, with the first POFs being much less sensitive to thermal treatment. The influence of annealing on the strain and temperature sensitivities of the fibres prior to FBG inscription is also discussed, where it is observed that the fibre produced from a two-step drawing process with well-defined pre-annealing of both preforms did not produce any significant difference in sensitivity. The results indicate the impact of preform thermal pre-treatment before the PMMA POFs drawing, which can be an essential characteristic in the view of developing POF sensors technology.

  18. Detection of the volatile organic compounds emitted from paints using optical fibre long period grating modified with the mesoporous nano-scale coating

    Science.gov (United States)

    Hromadka, Jiri; James, Stephen; Davis, Frank; Tatam, Ralph P.; Crump, Derrick; Korposh, Sergiy

    2015-09-01

    An optical fibre long period grating (LPG) modified with a mesoporous film infused with a calixarene as a functional compound was employed for the detection of a mixture of volatile organic compounds (VOCs). The sensing mechanism is based on the transduction of the refractive index change induced by the complexion of the VOCs with calixarene into a change in the form of the transmission spectrum of the LPG. An LPG, modified with a calixarene-infused coating comprising 5 cycles of silica nanoparticles/poly(allylamine hydrochloride) polycation (SiO2/PAH), was exposed to mixture of VOCs emitted from paint at conditions simulating ISO standards test (16000-10).

  19. Correlation between optic nerve head parameters and retinal nerve fibre layer thickness measured by spectral-domain optical coherence tomography in myopic eyes.

    Science.gov (United States)

    Hwang, Young H; Kim, Yong Y

    2012-01-01

      To evaluate the correlation between optic nerve head parameters and retinal nerve fiber layer thickness measured by Cirrus HD spectral-domain optical coherence tomography (Cirrus HD-OCT; Carl Zeiss Meditec) in healthy myopic eyes.   Cross-sectional study.   One hundred and sixty-one right eyes from 161 healthy young myopic subjects.   Optic nerve head parameters and retinal nerve fiber layer thickness were measured with the Cirrus HD-OCT. The distance between optic disc margin and scan circle (disc margin-to-scan distance) was measured on the Cirrus HD-OCT en-face optic nerve head image with aid of National Institutes of Health ImageJ image-analysis software (developed by Wayne Rasbands, National Institutes of Health, Bethesda, MD).   The correlations among optic nerve head parameters, retinal nerve fibre layer thickness and the disc margin-to-scan distance were evaluated with and without adjustment of the magnification effect.   Without correction of the magnification effect, the thicker average retinal nerve fiber layer was correlated with greater rim area and lower degree of myopia (P fibre layer was associated with greater disc area and greater rim area in univariate and multivariate analyses (P ≤ 0.028); however, degrees of myopia and the disc margin-to-scan distance were not significantly associated with average RNFL thickness (P ≥ 0.104).   Thicker average retinal nerve fibre layer thickness was associated with greater rim and disc areas. Disc margin-to-scan distance was not significantly correlated with average retinal nerve fibre layer thickness in healthy myopic eyes. © 2012 The Authors. Clinical and Experimental Ophthalmology © 2012 Royal Australian and New Zealand College of Ophthalmologists.

  20. 3d Finite Element Modelling of Non-Crimp Fabric Based Fibre Composite Based on X-Ray Ct Data

    DEFF Research Database (Denmark)

    Jespersen, Kristine Munk; Asp, Leif; Mikkelsen, Lars Pilgaard

    2017-01-01

    initiation and progression in the material. In the current study, the real bundle structure inside a non-crimp fabric based fibre composite is extracted from 3D X-ray CT images and imported into ABAQUS for numerical modelling.The local stress concentrations when loaded in tension caused by the fibre bundle...

  1. Detection and quantification of additives (urea, biuret and poultry litter) in alfalfas by NIR spectroscopy with fibre-optic probe.

    Science.gov (United States)

    González-Martín, Inmaculada; Hernández-Hierro, José Miguel

    2008-09-15

    The additives (urea, biuret and poultry litter) present in alfalfa, which contribute non-proteic nitrogen, were analysed using near infrared spectroscopy (NIRS) technology together with a remote reflectance fibre-optic probe. We used 75 samples of known alfalfa without additives and 75 samples with each of the additives, urea (0.01-10%), biuret (0.01-10%) and poultry litter (1-25%). Using the discriminant partial least squares (DPLS) algorithm, the presence or absence of the additives urea, biuret and poultry litter is classified and predicted with a high prediction rate of 96.9%, 100% and 100%, obtaining the equations of discrimination for each additive. The regression method employed for the quantification was modified partial least squares (MPLS). The equations were developed using the fibre-optic probe to determine the content of urea, biuret and poultry litter with multiple correlation coefficients (RSQ) and prediction corrected standard errors (SEP (C)) of 0.990, 0.28% for urea, 0.991, 0.29% for biuret and 0.925, 2.08% for poultry litter. The work permits the instantaneous and simultaneous prediction and determination of urea, biuret and poultry litter in alfalfas, applying the fibre-optic directly on the ground samples of alfalfa.

  2. Comparative Environmental Sustainability Assessment of Bio-Based Fibre Reinforcement Materials for Wind Turbine Blades

    DEFF Research Database (Denmark)

    Corona, Andrea; Markussen, Christen Malte; Birkved, Morten

    2015-01-01

    Over the recent decades biomaterials have been marketed successfully supported by the common perception that biomaterials and environmental sustainability de facto represents two sides of the same coin. The development of sustainable composite materials for wind turbine blades for small-scale wind...... categories, not only climate change, actually is supporting sustainable development or if the development of sustainable composite materials is more complex and perhaps even contra-intuitive due to complex trade-offs. Based on a case study 4 different types of fibres and fibre mixtures (flax, carbon, glass...... and flax/carbon, flax/glass mixed fibres) are compared in terms of environmental sustainability. Applying one of the most recent life cycle impact assessment methods, we demonstrate that the environmental sustainability of natural fibre based composite materials is similar or even lower, within certain...

  3. HDMI optical extender based on parallel optical transmitter and receiver

    Science.gov (United States)

    Luo, Zhixiang; Zhu, Zhishi; Zhang, Hailiang

    2009-08-01

    High-Definition Multimedia Interface(HDMI) can carry high quality multi-channel audio data and can carry all standard and highdefinition video formats. To send the information form video source to the display unit, the HDMI cable which carries four differential pairs is used. Now HDMI 1.3 increases its single-link bandwidth from 165MHz (4.95 gigabits per second) to 340 MHz (10.2 Gbps) to support the demands of future high definition display devices, so the traditional copper wire cable imposes limits on signal transmission distance and signal quality at so high speed. Optical fiber is of low dispersion, which in turn has the strength of longer signal transmission distance and better signal transmission quality in comparison to the traditional copper wire cable. So the optical extender consisting of two modules - one transmitter and one receiver- is developed. The transmitter connects to a computer/DVD player etc. The receiver connects to a display. Between the two modules, four-core ribbon fibre is used to transmit the video and audio signals. HDMI needs four differential pairs, so we design the parallel optical transmitter based on VCSEL array and VCSEL driver chip HXT3404 from Gigoptix and the parallel optical receiver based on PIN array and transimpedance amplifier chip HXR3404. Each channel can reach 3.125Gbps, so the data speed of the optical extender is 12.5Gbps. The experiment shows that the optical extender can transfer the video and audio data to the display uint 100 meter away.

  4. Selection of appropriate medial branch of the optic tract by fibres of ventral retinal origin during development and in regeneration: an autoradiographic study in Xenopus

    International Nuclear Information System (INIS)

    Straznicky, C.; Gaze, R.M.; Horder, T.J.

    1979-01-01

    The formation of the branches of the optic tract has been studied with the use of [ 3 H] -proline autoradiography, during development and during regeneration of the optic nerve in Xenopus with one compound ventral (VV) eye made by the embryonic fusion of two ventral eye fragments. The formation of the optic pathway was abnormal in that the lateral branch failed to develop, suggesting that fibres from a VV retina selectively entered the tectum via the medial branch during development. Three months after section of the optic nerve of a VV eye, regenerated fibres were present both in the contralateral and ipsilateral tecta. On the ipsilateral side regenerated fibres entered the tectum via the medial branch only. Retinal fibres entered the contralateral tectum through both branches in some animals and through the medial branch only in others. It is concluded that mechanical factors alone are insufficient to explain the phenomenon of selection of the appropriate medial branch fibres of ventral retinal origin either during development or in regeneration. Some form of fibre-substrate interaction seems to be necessary; and this ability of fibres from a VV eye to take the path appropriate for ventral retina argues strongly that the VV eye is not a regulated system in terms of cell specificities. 8author)

  5. Biodegradable composites based on L-polylactide and jute fibres

    DEFF Research Database (Denmark)

    Plackett, David; Løgstrup Andersen, T.; Batsberg Pedersen, W.

    2003-01-01

    in the 180-220 degreesC range were significantly higher than those of polylactide alone. Composite samples failed in a brittle fashion under tensile load and showed little sign of fibre pull-out. Examination of composite fracture surfaces using electron microscopy showed voids occurring between the jute...

  6. Compact fibre-based coherent anti-Stokes Raman scattering ...

    Indian Academy of Sciences (India)

    tral compression of femtosecond pulses emitted by a single highly compact fibre laser. Spectral compression of the broadband femtosecond pulses is achieved by generating narrow-band second harmonic (SH) pulses in crystals with large group- delay mismatch between the fundamental frequency (FF) and the SH pulses ...

  7. Analysis of mitochondrial mechanical dynamics using a confocal fluorescence microscope with a bent optical fibre.

    Science.gov (United States)

    Li, Yongbo; Honda, Satoshi; Iwami, Kentaro; Ohta, Yoshihiro; Umeda, Norihiro

    2015-11-01

    The cells in the cardiovascular system are constantly subjected to mechanical forces created by blood flow and the beating heart. The effect of forces on cells has been extensively investigated, but their effect on cellular organelles such as mitochondria remains unclear. We examined the impact of nano-Newton forces on mitochondria using a bent optical fibre (BOF) with a flat-ended tip (diameter exceeding 2 μm) and a confocal fluorescence microscope. By indenting a single mitochondrion with the BOF tip, we found that the mitochondrial elastic modulus was proportional to the (-1/2) power of the mitochondrial radius in the 9.6-115 kPa range. We stained the mitochondria with a potential-metric dye (TMRE) and measured the changes in TMRE fluorescence intensity. We confirmed that more active mitochondria exhibit a higher frequency of repetitive transient depolarization. The same trend was observed at forces lower than 50 nN. We further showed that the depolarization frequency of mitochondria decreases under an extremely large force (nearly 100 nN). We conclude that mitochondrial function is affected by physical environmental factors, such as external forces at the nano-Newton level. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  8. Temporal retinal nerve fibre layer thinning in cluster headache patients detected by optical coherence tomography.

    Science.gov (United States)

    Ewering, Carina; Haşal, Nazmiye; Alten, Florian; Clemens, Christoph R; Eter, Nicole; Oberwahrenbrock, Timm; Kadas, Ella M; Zimmermann, Hanna; Brandt, Alexander U; Osada, Nani; Paul, Friedemann; Marziniak, Martin

    2015-10-01

    The exact pathophysiology of cluster headache (CH) is still not fully clarified. Various studies confirmed changes in ocular blood flow during CH attacks. Furthermore, vasoconstricting medication influences blood supply to the eye. We investigated the retina of CH patients for structural retinal alterations with optical coherence tomography (OCT), and how these changes correlate to headache characteristics, oxygen use and impaired visual function. Spectral domain OCT of 107 CH patients - 67 episodic, 35 chronic, five former chronic sufferers - were compared to OCT from 65 healthy individuals. Visual function tests with Sloan charts and a substantial ophthalmologic examination were engaged. Reduction of temporal and temporal-inferior retinal nerve fibre layer (RNFL) thickness was found in both eyes for CH patients with a predominant thinning on the headache side in the temporal-inferior area. Chronic CH patients revealed thinning of the macula compared to episodic suffers and healthy individuals. Bilateral thinning of temporal RNFL was also found in users of 100% oxygen compared to non-users and healthy controls. Visual function did not differ between patients and controls. Our OCT findings show a systemic effect causing temporal retinal thinning in both eyes of CH patients possibly due to attack-inherent or medication-induced frequent bilateral vessel diameter changes. The temporal retina with its thinly myelinated parvo-cellular axons and its more susceptible vessels for the vasoconstricting influence of oxygen inhalation seems to be predisposed for tissue damage-causing processes related to CH. © International Headache Society 2015.

  9. Fibre Optic Notch Filter For The Antiproton Decelerator Stochastic Cooling System

    CERN Document Server

    Simmonds, Max Vincent John

    2016-01-01

    The project scope included reverse engineering, upgrading, and recovering the operational conditions of an existing fibre optic notch filter. Once operational, tests were to be preformed to confirm the performance of the temperature stabilisation. The end goal is to use said notch filter in the Antiproton Decelerator (AD) facility at CERN to help aid antimatter research. The notch filter was successfully reverse engineered and then documented. Changes were made in order to increase performance and reliability, and also allow easy integration into the AD. An additional phase was added whereby the notch filter was to be controller via a touchscreen computer, situated next to the filter, allowing engineers to set-up each of the electronic devices used. While one of the devices (Motorised Delay Line) can be controlled by the touchscreen computer, the other two cannot.Due to time constraints and difficulties with the Beckhoff TwincatII programming language, the USB devices were not able to be controlled via the To...

  10. Fabry-Perot micro-structured polymer optical fibre sensors for opto-acoustic endoscopy

    DEFF Research Database (Denmark)

    Broadway, Christian; Gallego, Daniel; Woyessa, Getinet

    2015-01-01

    Opto-Acoustic Endoscopy (OAE) requires sensors with a high sensitivity and small physical dimensions in order to facilitate integration into an endoscope of less than 1mm in diameter. We present fibre Bragg grating (FBG) and Fabry- Perot intrinsic fibre sensors for ultrasound detection. We present...

  11. Implementation of a four quadrant optic fibre bundle as a deflection sensor to get rid of heat sources in an AFM head

    International Nuclear Information System (INIS)

    Boukellal, Younes; Ducourtieux, Sebastien

    2015-01-01

    In the frame of developing a thermally passive atomic force microscope head, a new kind of 2D displacement sensor based on a four quadrant optic fibre bundle has been implemented. The aim is to replace the quad cell photodiode used in the optical beam deflection method to detect cantilever deflection. The use of the bundle as a position sensor has already been modelled and experimentally evaluated in a previous work. This article reports on the implementation of the bundle as a deflection sensor for atomic force microscopy. The main motivation for such a development was to reduce the heat sources in the instrument. To reach this goal the photodiode and its conditioning circuit used for the measurement of cantilever deflection has been externalized from the AFM head. For the same reason, the laser diode and its electronic driver have been deported using optic fibre. To test the AFM head prototype in real conditions, approach curves and AFM images have been performed. The results show that the bundle is very well suited for AFM applications that require very low heat sources such as metrological AFM where each error source has to be managed. (paper)

  12. Evaluation of Thermal and Thermomechanical Behaviour of Bio-Based Polyamide 11 Based Composites Reinforced with Lignocellulosic Fibres

    Directory of Open Access Journals (Sweden)

    Helena Oliver-Ortega

    2017-10-01

    Full Text Available In this work, polyamide 11 (PA11 and stone ground wood fibres (SGW were used, as an alternative to non-bio-based polymer matrices and reinforcements, to obtain short fibre reinforced composites. The impact of the reinforcement on the thermal degradation, thermal transitions and microstructure of PA11-based composites were studied. Natural fibres have lower degradation temperatures than PA11, thus, composites showed lower onset degradation temperatures than PA11, as well. The thermal transition and the semi-crystalline structure of the composites were similar to PA11. On the other hand, when SGW was submitted to an annealing treatment, the composites prepared with these fibres increased its crystallinity, with increasing fibre contents, compared to PA11. The differences between the glass transition temperatures of annealed and untreated composites decreased with the fibre contents. Thus, the fibres had a higher impact in the composites mechanical behaviour than on the mobility of the amorphous phase. The crystalline structure of PA11 and PA11-SGW composites, after annealing, was transformed to α’ more stable phase, without any negative impact on the properties of the fibres.

  13. Palladium coated fibre Bragg grating based hydrogen sensor

    International Nuclear Information System (INIS)

    Kasinathan, M.; Sosamma, S.; Kishore, S.; Elumalai, V.; Krishnan, R.; Babu Rao, C.; Dash, Sitaram; Murali, N.; Jayakumar, T.

    2011-01-01

    Detection of steam generator leaks in fast nuclear reactors is carried out by monitoring hydrogen in argon cover-gas. Hydrogen released during sodium cleaning of fast reactor components is required to be monitored. Hydrogen sensors with good sensitivity, stability and response time are required for all the above applications. We report a new type of hydrogen sensor with a Fibre Bragg Grating (FBG) coated with palladium thin film which is used to detect the leak of hydrogen gas in the Steam Generator (SG) module of the Fast Breeder Reactor (FBR). If water leaks into sodium, it results in sodium-water reaction. In this reaction hydrogen and sodium hydroxide are formed. Due to the explosive risk of hydrogen system, hydrogen sensors are of great interest in this case. It is known that hydrogen forms an explosive mixture with air once its concentration exceeds beyond the explosion limit of four percent. The advantages of FBG based hydrogen sensor over the other hydrogen sensors are its inherent property of safety from sparking, immunity to ambient electromagnetic interference. The sensing mechanism in this device is based on mechanical strain that is induced in the palladium coating when it absorbs hydrogen. This process physically stretches the grating and causes the grating period and grating's refractive index, to change. The Bragg wavelength shift is directly proportional to the strain induced and can be directly related to the percentage of hydrogen exposure. The online monitoring of palladium thin film coating on FBG is carried out and recorded the wavelength change and strain induced on the FBG. A hydrogen sensor set up have been fabricated which consists of SS vessel of capacity 10 litres, provided with pressure gauge, Argon filling line with a valve, Hydrogen injection line with flange, a vent line with valve and Hydrogen sensor fixing point. The Palladium coated FBG based Hydrogen sensor is tested in this experimental facility in the exposure of hydrogen in

  14. Two innovative solutions based on fibre concrete blocks designed for building substructure

    Science.gov (United States)

    Pazderka, J.; Hájek, P.

    2017-09-01

    Using of fibers in a high-strength concrete allows reduction of the dimensions of small precast concrete elements, which opens up new ways of solution for traditional construction details in buildings. The paper presents two innovative technical solutions for building substructure: The special shaped plinth block from fibre concrete and the fibre concrete elements for new technical solution of ventilated floor. The main advantages of plinth block from fibre concrete blocks (compared with standard plinth solutions) is: easier and faster assembly, higher durability and thanks to the air cavity between the vertical part of the block, the building substructure reduced moisture level of structures under the waterproofing layer and a comprehensive solution to the final surface of building plinth as well as the surface of adjacent terrain. The ventilated floor based on fibre concrete precast blocks is an attractive structural alternative for tackling the problem of increased moisture in masonry in older buildings, lacking a functional waterproof layer in the substructure.

  15. Hollow Core Photonic Crystal Fibre Comprising a Fibre Grating in the Cladding and its Applications

    DEFF Research Database (Denmark)

    2010-01-01

    An optical fibre is provided having a fibre cladding around a longitudinally extending optical propagation core. The cladding has a reflection region of a varying refractive index in the longitudinal direction.......An optical fibre is provided having a fibre cladding around a longitudinally extending optical propagation core. The cladding has a reflection region of a varying refractive index in the longitudinal direction....

  16. Influence of transmission bit rate on performance of optical fibre communication systems with direct modulation of laser diodes

    International Nuclear Information System (INIS)

    Ahmed, Moustafa F

    2009-01-01

    This paper reports on the influence of the transmission bit rate on the performance of optical fibre communication systems employing laser diodes subjected to high-speed direct modulation. The performance is evaluated in terms of the bit error rate (BER) and power penalty associated with increasing the transmission bit rate while keeping the transmission distance. The study is based on numerical analysis of the stochastic rate equations of the laser diode and takes into account noise mechanisms in the receiver. Correlation between BER and the Q-parameter of the received signal is presented. The relative contributions of the transmitter noise and the circuit and shot noises of the receiver to BER are quantified as functions of the transmission bit rate. The results show that the power penalty at BER = 10 -9 required to keep the transmission distance increases moderately with the increase in the bit rate near 1 Gbps and at high bias currents. In this regime, the shot noise is the main contributor to BER. At higher bit rates and lower bias currents, the power penalty increases remarkably, which comes mainly from laser noise induced by the pseudorandom bit-pattern effect.

  17. Low cost membrane contactors based on hollow fibres

    Science.gov (United States)

    Dohnal, Mirko; Vesely, Tomas; Raudensky, Miroslav

    2012-04-01

    Membrane contactors are used to solve different chemical engineering tasks (e.g. water saturation with gases). Such elements are traditionally used for bubble less oxidation of blood. However, their industrial applications are rather limited by their high investment costs. This is probably the main reason why membrane contactors are not used so widely, e.g. classical absorbers, etc. If potted bundles of hollow fibres are available, then it is a relatively simple task to design an ad hoc membrane contactor. However, it must be emphasised that to achieve the highest mass transfer efficiency requires a rather time-consuming tuning of each ad hoc designed contactor. To check the differences by water evaporation were aligned two modes, the water inside the hollow fibre membrane and fan air outside, next with the water outsides and flowing pressure air inside the membrane.

  18. Low cost membrane contactors based on hollow fibres

    Directory of Open Access Journals (Sweden)

    Raudensky Miroslav

    2012-04-01

    Full Text Available Membrane contactors are used to solve different chemical engineering tasks (e.g. water saturation with gases. Such elements are traditionally used for bubble less oxidation of blood. However, their industrial applications are rather limited by their high investment costs. This is probably the main reason why membrane contactors are not used so widely, e.g. classical absorbers, etc. If potted bundles of hollow fibres are available, then it is a relatively simple task to design an ad hoc membrane contactor. However, it must be emphasised that to achieve the highest mass transfer efficiency requires a rather time-consuming tuning of each ad hoc designed contactor. To check the differences by water evaporation were aligned two modes, the water inside the hollow fibre membrane and fan air outside, next with the water outsides and flowing pressure air inside the membrane.

  19. Applying Fibre-Optic Distributed Temperature Sensing to Near-surface Temperature Dynamics of Broadacre Cereals During Radiant Frost Events.

    Science.gov (United States)

    Stutsel, B.; Callow, J. N.

    2017-12-01

    Radiant frost events, particularly those during the reproductive stage of winter cereal growth, cost growers millions of dollars in lost yield. Whilst synoptic drivers of frost and factors influencing temperature variation at the landscape scale are relatively well understood, there is a lack of knowledge surrounding small-scale temperature dynamics within paddocks and plot trials. Other work has also suggested a potential significant temperature gradient (several degrees) vertically from ground to canopy, but this is poorly constrained experimentally. Subtle changes in temperature are important as frost damage generally occurs in a very narrow temperature range (-2 to -5°C). Once a variety's damage threshold is reached, a 1°C difference in minimum temperature can increase damage from 10 to 90%. This study applies Distributed Temperature Sensing (DTS) using fibre optics to understand how minimum temperature evolves during a radiant frost. DTS assesses the difference in attenuation of Raman scattering of a light pulse travelling along a fibre optic cable to measure temperature. A bend insensitive multimode fibre was deployed in a double ended duplex configuration as a "fence" run through four times of sowing at a trial site in the Western Australian Wheatbelt. The fibre optic fence was 160m long and 800mm tall with the fibre optic cable spaced 100mm apart vertically, and calibrated in ambient water ( 10 to 15oC) and a chilled glycol ( -8 to-10 oC) baths. The temperature measurements had a spatial resolution of 0.65m and temporal resolution of 60s, providing 2,215 measurements every minute. The results of this study inform our understanding of the subtle temperature changes from the soil to canopy, providing new insight into how to place traditional temperature loggers to monitor frost damage. It also addresses questions of within-trial temperature variability, and provides an example of how novel techniques such as DTS can be used to improve the way temperature

  20. The study of mechanical properties of pineapple leaf fibre reinforced tapioca based bioplastic resin composite

    Directory of Open Access Journals (Sweden)

    Mathivanan D.

    2016-01-01

    Full Text Available Natural fibre reinforced composite has brought the material engineering to a high new level of research. Natural fibres are compatible with matrices like polypropylene and can be used as reinforcement material to reduce the composition of plastic in a material. Natural fibres such as kenaf, pineapple leaf, and coir already found its importance in reducing the dependence of petroleum based products. However the biodegradability of the product at the end of the intended lifespan is still questionable. This has led many researches to look for a suitable replacement for synthetic fibres and achieve better adhesion between fibre and matrix. In this study, fiber and matrix which are hydrophilic in nature was used and the mixture was extruded and hot compressed to acquire better mechanical properties. The specimens were fabricated and tested according to ASTM D638. The 30% composition illustrates the best average modulus value among other composition and from this result it can be concluded that the increase of PALF fibre in TBR composite increases the modulus strength of the composite.

  1. Radiation Pattern Measurement of a Low-Profile Wearable Antenna Using an Optical Fibre and a Solid Anthropomorphic Phantom

    Directory of Open Access Journals (Sweden)

    Tian Hong Loh

    2014-08-01

    Full Text Available This paper presents a study into radiation pattern measurements of an electrically small dielectric resonator antenna (DRA operating between 2.4 and 2.5 GHz in the industrial, scientific and medical (ISM radio band for body-centric wireless communication applications. To eliminate the distortion of the radiation pattern associated with the unwanted radiation from a metallic coaxial cable feeding the antenna we have replaced it with a fibre optic feed and an electro-optical (EO transducer. The optical signal is then converted back to RF using an Opto-Electric Field Sensor (OEFS system. To ensure traceable measurements of the radiation pattern performance of the wearable antenna a generic head and torso solid anthropomorphic phantom model has been employed. Furthermore, to illustrate the benefits of the method, numerical simulations of the co-polar and cross-polar H-plane radiation patterns at 2.4, 2.45, and 2.5 GHz are compared with the measured results obtained using: (i an optical fibre; and (ii a metallic coaxial cable.

  2. Photonic Crystal Fibres as the Transmission Medium for Future Optical Communication Systems

    DEFF Research Database (Denmark)

    Zsigri, Beata

    2006-01-01

    of index guiding PCFs as transmission media, as nonlinear media for signal processing or as dispersion compensating fibre for future high capacity long-haul transmission systems is demonstrated. Finally, the telecommunication applications of photonic bandgap fibres are investigated. This work focusses...... on air-guiding photonic bandgap fibres (AG-PBGFs) and their system applications. The first and currently only reported data transmission over AG-PBGF is described. The potentials and current limitations of AG-PBGFs as transmission fibres are discussed. A polarisation delay interferometer, exploiting...... begun only recently. This thesis follows the evolution of PCFs as transmission media from the beginning up to now and presents state-of-the-art results of their various possible system applications. Index guiding PCFs have been investigated for transmission purposes. In this thesis, some of the initial...

  3. Development of a TiO{sub 2}-coated optical fiber reactor for water decontamination; Developpement d'un reacteur a base de fibres optiques photocatalytiquement actives pour la depollution de l'eau

    Energy Technology Data Exchange (ETDEWEB)

    Danion, A

    2004-09-15

    The objective of this study was to built and to study a photo-reactor composed by TiO{sub 2}-coated optical fibers for water decontamination. The physico-chemical characteristics and the optical properties of the TiO{sub 2} coating were first studied. Then, the influences of different parameters as the coating thickness, the coating length and the coating volume were investigated both on the light transmission in the TiO{sub 2}- coated fiber and on the photo-catalytic activity of the fiber for a model compound (malic acid). The photo-catalytic degradation of malic acid was optimized using the experimental design methodology allowing to build a multi-fiber reactor comprising 57 optical fibers. The photo-degradation of malic acid was conducted in the multi-fiber reactor and it was demonstrated that the multi-fiber reactor was more efficient than the single-fiber reactor at the same fibers density. Finally, the multi-fiber reactor was applied to the photo-degradation of a fungicide, called fenamidone, and a degradation pathway was proposed. (author)

  4. Tunable error-free optical frequency conversion of a 4ps optical short pulse over 25 nm by four-wave mixing in a polarisation-maintaining optical fibre

    Science.gov (United States)

    Morioka, T.; Kawanishi, S.; Saruwatari, M.

    1994-05-01

    Error-free, tunable optical frequency conversion of a transform-limited 4.0 ps optical pulse signalis demonstrated at 6.3 Gbit/s using four-wave mixing in a polarization-maintaining optical fibre. The process generates 4.0-4.6 ps pulses over a 25nm range with time-bandwidth products of 0.31-0.43 and conversion power penalties of less than 1.5 dB.

  5. Thermal Hypersensitisation and Corresponding Grating Evolution in Ge-doped Optical Fibre

    DEFF Research Database (Denmark)

    Sørensen, Henrik Rokkjær; Canning, John; Kristensen, Martin

    2005-01-01

    Low temperature (sub 1000oC) thermal hypersensitisation is reported in germanosilicate fibre. Thermal excitation is dispersive involving a range of glass sites leading to a behaviour resembling type IIA grating response at 500oC.......Low temperature (sub 1000oC) thermal hypersensitisation is reported in germanosilicate fibre. Thermal excitation is dispersive involving a range of glass sites leading to a behaviour resembling type IIA grating response at 500oC....

  6. Dynamic range enhancement and amplitude regeneration in single pump fibre optic parametric amplifiers using DPSK modulation

    DEFF Research Database (Denmark)

    Peucheret, Christophe; Lorenzen, Michael Rodas; Seoane, Jorge

    2008-01-01

    Input power dynamic range enhancement and amplitude regeneration of highly distorted signals are demonstrated experimentally for 40 Gbit/s RZ-DPSK in a single-pump fibre parametric amplifier with 22 dB smallsignal gain.......Input power dynamic range enhancement and amplitude regeneration of highly distorted signals are demonstrated experimentally for 40 Gbit/s RZ-DPSK in a single-pump fibre parametric amplifier with 22 dB smallsignal gain....

  7. Fibre illumination system

    DEFF Research Database (Denmark)

    2012-01-01

    the proximal end of the collection optics into the first end of the input fibre, each collector element having a principal axis for the collection of light defining an optical axis of the collector element. The optical axes of the collector elements are arranged in a radially outward pointing multi......Source: EP2426402A The invention relates to a fibre illumination module and system for the collection and delivery of daylight for illumination purposes. The fibre illumination module comprises a plurality of collector elements, each collector element comprising an input fibre having a first end...... and a second end, and a collection optics, the collection optics being configured to receive light incident on a distal end of the collection optics, to transfer at least partially the incident light to a proximal end of the collection optics, and to couple at least partially the transferred light from...

  8. On the Theory of the Modulation Instability in Optical Fibre Amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Turitsyn, S K; Rubenchik, A M; Fedoruk, M P

    2010-05-10

    The modulation instability (MI) in optical fiber amplifiers and lasers with anomalous dispersion leads to CW radiation break-up and growth of multiple pulses. This can be both a detrimental effect limiting the performance of amplifiers, and also an underlying physical mechanism in the operation of MI-based devices. Here we revisit the analytical theory of MI in fiber optical amplifiers. The results of the exact theory are compared with the previously used adiabatic approximation model and the range of applicability of the later is determined.

  9. Study of optically stimulated luminescence (OSL) for radiation detection. Application to an optical fibre γ-radiation sensor

    International Nuclear Information System (INIS)

    Roy, O.

    1998-01-01

    This work shows up the usefulness of the Optically Stimulated Luminescence (OSL) to resolve radioprotection problems. We study the use of OSL as a gamma dosimetric technique with respect to the ALARA's concept (As Low As Reasonably Achievable). A new approach based on optical fibers and luminescent materials showing OSL properties (closely related to Thermoluminescence phenomena) is presented in order to improve the remote real time dosimetry monitoring. Like thermoluminescent materials (TLD), OSL materials can trap charges under an irradiation (UV, X, γ,...). Instead of heating, the charges trapped are released by light stimulation and produce a visible luminescence which amount is proportional to trap the 'data stored' left by irradiation, enabling the dose measurement. The OSL phenomenon offers the same advantages as TLD plus the interesting possibility of a remote optical stimulation. The end-user objective deals with the development of a γ-radiation Optical FIber Sensor (OFS) for dose measurement which can offer new functionalities based on OSL materials coupled with an optical fiber. Rare earth doped Alkaline Earth Sulphides (AES), BAFX:EU 2+ (X = Cl, Br, I) and halogen alkaline have been studied (crystalline form, synthesis techniques, influence of dopants and color centers). Their characteristics are presented and extensively discussed. A specific experimental set-up to characterise various OSL phosphors has been developed. It allows the study of sensitivity, linearity, time decay behaviour of OSL signal and zeroing time. A joint study of OSL and TL has shown the technical limitations as well as the thermal fading and the origin of the long zeroing time. An Optical Fiber Sensor (OFS) based on OSL and using MgS:Sm has been developed for practical applications on nuclear fields. Its specifications are presented and discussed, moreover improvements are proposed. (author)

  10. Photonic Crystal Fibres

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Sanchez Bjarklev, Araceli

    Photonic crystal fibres represent one of the most active research areas today in the field of optics. The diversity of applications that may be addressed by these fibres and their fundamental appeal, by opening up the possibility of guiding light in a radically new way compared to conventional...... optical fibres, have spun an interest from almost all areas of optics and photonics. The aim of this book is to provide an understanding of the different types of photonic crystal fibres and to outline some of the many new and exciting applications that these fibres offer. The book is intended for both...... readers with a general interest in photonic crystals, as well as for scientists who are entering the field and desire a broad overview as well as a solid starting point for further specialized stuides. Teh book, therefore, covers bothe general aspects such as the link from classical optics to photonic...

  11. A double-fibre Fabry–Perot sensor based on modified fringe counting and direct phase demodulation

    International Nuclear Information System (INIS)

    Li, M; Tong, B; Guo, J J; Arsad, N

    2013-01-01

    A modified double-fibre Fabry–Perot cavity is developed for determination of the fringe moving direction and higher sensitivity in applications of liquid level and displacement sensors. Two fibres are integrated into a silica ferrule where the ends of the two fibres in the ferrule serve as the front surfaces of the Fabry–Perot cavities, and a diaphragm, which is replaced by a moving mirror for measurement of displacement, serves as the rear surface for both cavities in liquid level sensing. Our design has no strict requirements for a specific phase difference between the two optical paths, just a constant difference resulting from the processing error between the two fibre end positions rather than a precise optical path difference of λ/8 to judge the pattern shift direction. Experimental results demonstrate the feasibility of this approach to determining the fringe moving direction, a displacement sensitivity of 3 µm and good linearity for both applications. (paper)

  12. The use of plastic optical fibres and shape memory alloys for damage assessment and damping control in composite materials

    Science.gov (United States)

    Kuang, K. S. C.; Cantwell, W. J.

    2003-08-01

    This paper reports the use of a plastic fibre sensor for detecting impact damage in carbon fibre epoxy cantilever beams by monitoring their damping response under free vibration loading conditions. The composite beams were impacted at impact energies up to 8 J. The residual strengths and stiffnesses of the damaged laminates were measured in order to relate reductions in their mechanical properties to changes in their damping characteristics. Here, optical fibre sensors were surface bonded to carbon fibre composite beams which were subjected to free vibration tests to monitor their dynamic response. In the second part of this study, Ni-Ti shape memory alloy (SMA) wires were employed to control and modify the damping response of a composite beam. The SMA wires were initially trained to obtain the desired shape when activated. Here, the trained SMA wires were heated locally using a nickel/chromium wire that was wrapped around the trained region of the SMA. By using this method to activate the SMA wire (as opposed to direct electrical heating), it is possible to obtain localized actuation without heating the entire length of the wire. This procedure minimizes any damage to the host material that may result from local heat transfer between the SMA wire and the composite structure. In addition, the reduction in power requirements to achieve SMA activation permits the use of small-size power packs which can in turn lead to a potential weight reduction in weight-critical applications. The findings of this study demonstrate that a trained SMA offers a superior damping capability to that exhibited by an 'as-supplied' flat-annealed wire.

  13. Real-time chest-wall-motion tracking by a single optical fibre grating: a prospective method for ventilator triggering.

    Science.gov (United States)

    Ivanovic, Marija D; Petrovic, Jovana; Savic, Andrej; Gligoric, Goran; Miletic, Marjan; Vukcevic, Miodrag; Bojovic, Bosko; Hadzievski, Ljupco; Allsop, Tom D P; Webb, David J

    2018-03-19

    The ventilators involved in non-invasive mechanical ventilation commonly provide ventilator support via a facemask. The interface of the mask with a patient promotes air leaks that cause errors in the feedback information provided by a pneumatic sensor and hence patient-ventilator asynchrony with multiple negative consequences. Our objective is to test the possibility of using chest-wall motion measured by an optical fibre-grating sensor as a more accurate non-invasive ventilator triggering mechanism. Approach: The basic premise of our approach is that the measurement accuracy can be improved by using a triggering signal that precedes pneumatic triggering in the neuro-ventilatory coupling sequence. We propose a technique that uses the measurement of chest-wall curvature by a long-period fibre-grating sensor. The sensor was applied externally to the rib-cage and interrogated in the lateral (edge) filtering scheme. The study was performed on 34 healthy volunteers. Statistical data analysis of the time lag between the fibre-grating sensor and the reference pneumotachograph was preceded by the removal of the unwanted heartbeat signal by wavelet transform processing. Main results: The results show a consistent fibre-grating signal advance with respect to the standard pneumatic signal by (230±100) ms in both the inspiratory and expiratory phases. We further show that heart activity removal yields a tremendous improvement in sensor accuracy by reducing it from 60 ml to 0.3 ml. Significance: The results indicate that the proposed measurement technique may lead to a more reliable triggering decision. Its imperviousness to air leaks, non-invasiveness, low-cost and ease of implementation offer good prospects for applications in both clinical and homecare ventilation. . © 2018 Institute of Physics and Engineering in Medicine.

  14. Remote System for Detection of Low-Levels of Methane Based on Photonic Crystal Fibres and Wavelength Modulation Spectroscopy

    Directory of Open Access Journals (Sweden)

    J. P. Carvalho

    2009-01-01

    Full Text Available In this work we described an optical fibre sensing system for detecting low levels of methane. The properties of hollow-core photonic crystal fibres are explored to have a sensing head with favourable characteristics for gas sensing, particularly in what concerns intrinsic readout sensitivity and gas diffusion time in the sensing structure. The sensor interrogation was performed applying the Wavelength Modulation Spectroscopy technique, and a portable measurement unit was developed with performance suitable for remote detection of low levels of methane. This portable system has the capacity to simultaneously interrogate four remote photonic crystal fibre sensing heads.

  15. A Quality Function Deployment-Based Expert System for Cotton Fibre Selection

    Science.gov (United States)

    Chakraborty, Shankar; Prasad, Kanika

    2018-01-01

    The textile industries have seen resurgence in customers' demand for quality products during the preceding few years. This product range is extremely varied, with hand-spun and hand-woven products at one end of the spectrum, while products manufactured from the capital intensive sophisticated machineries at the other end. Since, cotton fibres are predominantly employed as the raw material for manufacturing these products, their proper selection is crucial for sustainable development of the textile/spinning industries. However, availability of numerous cotton fibre alternatives with various physical properties makes this selection process unwieldy and time consuming. Thus, there is need for a structured approach that can incorporate customers' demand into the selection process. This paper demonstrates the application of a structured and logical procedure of selecting the best cotton fibre type to fulfill a set of specified end product requirements through design and development of a quality function deployment (QFD)-based expert system. The QFD technique is employed here to provide due importance to the customers' spoken and unspoken needs, and subsequently calculate the priority weights of the considered cotton fibre properties. Two real time illustrative examples are presented to explicate the applicability and potentiality of the developed expert system to resolve cotton fibre selection problems.

  16. Application of Fiber Optic Instrumentation (Validation des systemes d’instrumentation a fibres optiques)

    Science.gov (United States)

    2012-07-01

    au stade des conditions d’opérations aériennes réalistes. La densité d’intégration de capteurs dans les fibres a été accrue de plusieurs ordres de...grandeur et les progrès réalisés en termes de faisabilité de capteurs continus sont rapides. Les systèmes à fibres optiques vont révolutionner...de recueillir avec les systèmes de capteurs embarqués classiques. Cette AGARDograph expose l’état actuel de la technique et fournit un cadre de

  17. Detection of progression of glaucomatous retinal nerve fibre layer defects using optical coherence tomography-guided progression analysis.

    Science.gov (United States)

    Hwang, Young Hoon; Kim, Min Kyung; Wi, Jae Min; Chung, Jae Keun; Lee, Kwan Bok

    2018-01-01

    The aim was to investigate the agreement for detection of progression of glaucomatous retinal nerve fibre layer defects (RNFLD) between optical coherence tomography-guided progression analysis (OCT GPA) and conventional red-free fundus photography. Four hundred and fifteen glaucomatous eyes that underwent at least four serial red-free photographic and OCT examinations were included in the study. Based on the inspection of the red-free fundus photographs and GPA maps, RNFLD progression was defined as the development of a new defect, widening or deepening of a pre-existing RNFLD in red-free fundus photography (photographic progression) or 'Likely Loss' on a GPA map (GPA progression). The agreement of photographic and OCT GPA progression and the factors influencing it, including refractive error, severity of glaucoma (mean deviation of the visual field), type of RNFLD (localised versus diffuse), width of the baseline RNFLD, type of RNFLD progression (new defect, widening, deepening) and location of RNFLD progression (clock-hour sector) were assessed. Among the 415 eyes, 82 (19.8 per cent) showed photographic or GPA progression. Among the 82 eyes with progression, progression was detected only in red-free fundus photography in nine (11.0 per cent) eyes and only in GPA in 32 (39.0 per cent) eyes. In 41 eyes (50.0 per cent), progression was detected with both methods. Detection of RNFLD progression only in GPA was associated with a higher myopia, diffuse RNFLD, deepening of the RNFLD and RNFLD progression at the 6, 9 and 12 o'clock positions (p < 0.05). OCT GPA may be a useful supplement to conventional red-free fundus photography for detecting RNFLD progression. © 2017 Optometry Australia.

  18. Towards reinforcement solutions for urban fibre/fabric waste using bio-based biodegradable resins.

    Science.gov (United States)

    Agrawal, Pramod; Hermes, Alina; Bapeer, Solaf; Luiken, Anton; Bouwhuis, Gerrit; Brinks, Ger

    2017-10-01

    The main research question is how to systematically define and characterize urban textile waste and how to effectively utilise it to produce reinforcement(s) with selected bio-based biodegradable resin(s). Several composite samples have been produced utilising predominantly natural and predominantly synthetic fibres by combining loose fibres with PLA, nonwoven fabric with PLA, woven fabric with PLA, two-layer composite & four-layer composite samples. Physio-chemical characterisations according to the established standards have been conducted. The present work is a step toward the circular economy and closing the loop in textile value chain.

  19. Impact of third-order fibre dispersion on the evolution of parabolic optical pulses

    Science.gov (United States)

    Bale, Brandon G.; Boscolo, Sonia

    2010-01-01

    We develop a perturbation analysis that describes the effect of third-order dispersion on the similariton pulse solution of the nonlinear Schrödinger equation in a fibre gain medium. The theoretical model predicts with sufficient accuracy the pulse structural changes induced, which are observed through direct numerical simulations.

  20. A fibre-optic UV system for H$_{2}$SO$_{4}$ production in aerosol chambers causing minimal thermal effects

    CERN Document Server

    Kupc, A; Onnela, A; Duplissy, J; Mathot, S; Danielczok, A; Walther, H; Minginette, P; Rondo, L; Ickes, L; Curtius, J; Wagner, P E; Amorim, A; Lima, J M; Ehrhart, S; Kurten, A

    2011-01-01

    A novel fibre-optic UV illumination system for sulphuric acid (H(2)SO(4)) production has been developed. The illumination system described in this paper provides sufficient ultraviolet light (UV) power while causing practically no thermal effect on the aerosol chamber (temperature variation <0.005 degrees C at full UV illumination). A similar thermal stability has not been achieved in other comparable experimental set-ups so far. The spectrum provided by the fibre-optic UV system corresponds to the UVB region, illuminates the chamber in a reasonably uniform way and is comparable to the ground level actinic flux. The UV system has been installed for the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber experiments at CERN. Precise, easily-adjustable and reproducible concentrations of H(2)SO(4) were generated by adjusting the UV light intensity. This paper gives an overview on the design of this new system as well as insights on its performance and application. (C) 2011 Elsevier Ltd. All rights reserved.