WorldWideScience

Sample records for based optical fibres

  1. Optical Fibre Based Frequency Shifters Project

    Science.gov (United States)

    1991-01-28

    A fibre optic frequency shifter can be used to replace the Bragg cell acousto-optic modulator, currently used to generate low frequency optical...carriers, in fibre optic communications and sensor systems. This new form of frequency shifter, being an all fibre device, in which the propagating optical...large number of workers in recent years, (for example references [2-81 and those contained therein). The main elements of a fibre - optic frequency

  2. Multicore optical fibre and fibre-optic delay line based on it

    Science.gov (United States)

    Egorova, O. N.; Astapovich, M. S.; Belkin, M. E.; Semjonov, S. L.

    2016-12-01

    The first switchable fibre-optic delay line based on a 1300-{\\text{m}}-long multicore optical fibre has been fabricated and investigated. We have obtained signal delay times of up to 45 \\unicode{956}{\\text{s}} at 6.43-\\unicode{956}{\\text{s}} intervals. Sequential signal propagation through the cores of the multicore optical fibre makes it possible to reduce the fibre length necessary for obtaining a predetermined delay time, which is important for reducing the weight and dimensions of devices based on the use of fibre-optic delay lines.

  3. Optical inclinometer based on fibre-taper-modal Michelson interferometer

    Science.gov (United States)

    Amaral, L. M. N.; Frazão, O.; Santos, J. L.; Lobo Ribeiro, A. B.

    2010-09-01

    An inclinometer sensor based on optical fibre-taper-modal Michelson interferometer is demonstrated. The magnitude of the tilt (bending angle of the fibre taper interferometer) is obtained by passive interferometric interrogation based on the generation of two quadrature phase-shifted signals from two fibre Bragg gratings. Optical phase-to-rotation sensitivity of 1.13 rad/degree with a 14 mrad/√Hz resolution is achieved.

  4. Erbium-doped nanoparticles in silica-based optical fibres

    CERN Document Server

    Blanc, Wilfried; Dussardier, Bernard; 10.1504/IJNT.2012.045350

    2012-01-01

    Developing of new rare-earth (RE)-doped optical fibres for power amplifiers and lasers requires continuous improvements in the fibre spectroscopic properties (like shape and width of the gain curve, optical quantum efficiency, resistance to spectral hole burning and photodarkening...). Silica glass as a host material for fibres has proved to be very attractive. However, some potential applications of RE-doped fibres suffer from limitations in terms of spectroscopic properties resulting from clustering or inappropriate local environment when doped into silica. To this aim, we present a new route to modify some spectroscopic properties of RE ions in silica-based fibres based on the incorporation of erbium ions in amorphous dielectric nanoparticles, grown in-situ in fibre preforms. By adding alkaline earth elements, in low concentration into silica, one can obtain a glass with an immiscibility gap. Then, phase separation occurs under an appropriate heat treatment. We investigated the role of three alkaline-earth...

  5. Fabrication of silicon based glass fibres for optical communication

    Indian Academy of Sciences (India)

    Vivek P Kude; R S Khairnar

    2004-02-01

    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. The fibre drawing process consists of various steps such as heating the preform at elevated temperature, diameter monitor, primary and secondary coating, and ultra violet radiation curing. The fibres are then characterized for their geometrical and optical properties. The drawn fibre has diameter of core and cladding to be 8.3 m and 124.31 m, respectively whereas non-circularity is found to be 4.17% for core and 0.26% for cladding as seen from phase plot. Mode field diameter is found to be 8.9 m and 9.2 m using Peterman II and Gaussian method, respectively. The fabricated fibres showed the signal attenuation of 0.35 dB/km and 0.20 dB/km for 1310 nm and 1550 nm, respectively as measured by the optical time domain reflectometer (OTDR).

  6. 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.

    2017-01-01

    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. PMID:28098825

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

    Directory of Open Access Journals (Sweden)

    Miguel Hernaez

    2017-01-01

    Full Text Available 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.

  8. An Optical Fibre-Based Sensor for Respiratory Monitoring

    Directory of Open Access Journals (Sweden)

    Marek Krehel

    2014-07-01

    Full Text Available In this paper, a textile-based respiratory sensing system is presented. Highly flexible polymeric optical fibres (POFs that react to applied pressure were integrated into a carrier fabric to form a wearable sensing system. After the evaluation of different optical fibres, different setups were compared. To demonstrate the feasibility of such a wearable sensor, the setup featuring the best performance was placed on the human torso, and thus it was possible to measure the respiratory rate. Furthermore, we show that such a wearable system enables to keep track of the way of breathing (diaphragmatic, upper costal and mixed when the sensor is placed at different positions of the torso. A comparison of the results with the output of some commercial respiratory measurements devices confirmed the utility of such a monitoring device.

  9. 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.

  10. Fibre-Optic Gyroscope

    Directory of Open Access Journals (Sweden)

    V. N. Saxena

    1983-04-01

    Full Text Available Comparative study of mechanical, ring-laser and fibre-optic gyroscopes has been made. The single mode fibre-optic gyroscope having a large number of turns of the optical fibre in the spool, replacing He-Ne gas laser by a GaAs laser diode, there by reducing the noise level, and using fully integrated fibre-optics, works out to be the best in the final analysis, for safe navigation and homing of the guided missiles.

  11. 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.

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

    Institute of Scientific and Technical Information of China (English)

    SUN Li-Qun; DONG Bo; WANG Yong-Xin; Evan LALLY; WANG An-Bo

    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.

  13. 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.

  14. Improved optical amplification using metamaterial based split ring structures in optical fibres

    Science.gov (United States)

    Prakash, Geetha; Nigam, Raaghvam; Das, Sovan; Chellappa, Sharath

    2016-04-01

    Optical fibres provide the best solutions for transmitting high speed, large amounts of data with good power efficiency. However such transmission would also need amplification for transmission over large distances. Erbium Doped Fibre Amplifiers(EDFAs) are currently being used for optical amplification. But good amplification is achievable with multiple stages and considerable length of EDFA fibres. In this paper we compare the use of Silver Split Ring Resonators(SRRs) , Gold Nano Rods and Silver Fishnet structures which give metamaterial properties to be used in optical fibres to give better amplification than EDFA based fibres. Metamaterials belong to a new class of materials with negative values for permittivity and permeability. Such materials would exhibit negative refractive index leading to these materials being called as left handed media.If such left handed media have an internal structure made of dimensions much smaller than the wavelength but sufficiently thick to exhibit bulk properties, using other optical domains such as plasmonics, it is possible to control light interactions and propagation. Artificial structures smaller than the wavelength of light can be used to enhance electric and magnetic fields. Surface plasmons can be excited on a metal and this can enhance the electric field at the surface. Our paper proposes the use of this phenomenon of achieving gain at optical frequencies by using SRRs, Fishnet structures , Nano Rods. We compare the performance of these structures and observe that they provide gain which is much more than that provided by EDFAs.

  15. 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...... and force sensitivity measurements are taken before and after annealing. Parameters such as annealing time and annealing temperature are investigated. The change of the fibre diameter due to water absorption and the annealing process is also considered. The results show that annealing the polymer optical...... fibre tends to increase the strain, stress and force sensitivity of the photo-inscribed sensor....

  16. 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 and ...

  17. Er doped oxide nanoparticles in silica based optical fibres

    CERN Document Server

    Blanc, Wilfried; Paul, M C

    2009-01-01

    Erbium doped materials are of great interest in optical telecommunications due to the Er3+ intra-4f emission at 1.54 ?m. Erbium doped fibre amplifiers (EDFA) were developed in silica glass because of the low losses at this wavelength and the reliability of this glass. Developments of new rare earth doped fibre amplifiers aim to control their spectroscopic properties including shape and width of the gain curve and optical quantum efficiency. Standard silica glass modifiers, such as aluminium, result in very good properties in current EDFA. However, for more drastic spectroscopic changes, more important modifications of the rare earth ions local environment are required. To address this aim, we present a fibre fabrication route creating rare earth doped calcia?silica or calcia?phosphosilica nanoparticles embedded in silica glass. By adding alkaline earth elements such as calcium, in low concentration, one can obtain a glass with an immisci- bility gap so that phase separation occurs with an appropriate heat tre...

  18. Extreme Silica Optical Fibre Gratings

    Directory of Open Access Journals (Sweden)

    Kevin Cook

    2008-10-01

    Full Text Available A regenerated optical fibre Bragg grating that survives temperature cycling up to 1,295°C is demonstrated. A model based on seeded crystallisation or amorphisation is proposed.

  19. A beam monitor detector based on doped silica and optical fibres

    CERN Document Server

    Braccini, S; Giacoppo, F; Kreslo, I; Nesteruk, K P; Nirkko, M; Weber, M; Scampoli, P; Neff, M; Pilz, S; Romano, V

    2011-01-01

    A beam monitor detector based on doped silica and optical fibres has been designed, constructed and tested, mainly for accelerators used in medical applications. We conceived a general-purpose device, suitable either for low currents used in hadrontherapy or for high currents typical for radioisotope production, as well as for both pulsed and continuous beams. Scintillation light produced by Ce and Sb doped silica fibres moved across the beam is measured, giving information on its position, shape and intensity. The coupling of the doped fibre to an ordinary optical fibre allows the read-out of the signal far away from the radiation source. Mostly based on commercial components, the detector is easy to install and operate also in a high radiation environment due to the absence of any radiation sensitive electronics located near the fibre. The first successful beam tests triggered new developments toward the realization of a two-dimensional beam profiler and the miniaturization of the full device.

  20. Optical Stabilizer Based on Optical Bistable Devices with All-Fibre Construction

    Institute of Scientific and Technical Information of China (English)

    LI Cheng; YE Hong-An; ZHAO Xue-Zeng; YANG Jiu-Ru; ZHANG Xin-Ming; LU Guo-Hui

    2004-01-01

    @@ We propose a fibre optical stabilizer constituted by a photoelectric-hybrid optical bistable device in which fibre Bragg grating is used as a light intensity modulator. The intensity noise-reducing ability is well improved through the method by employing two feed signals. As a result, the light intensity variation can be reduced to ~ 1/64.

  1. 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 ...

  2. 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....

  3. Toluene optical fibre sensor based on air microcavity in PDMS

    Science.gov (United States)

    Kacik, Daniel; Martincek, Ivan

    2017-03-01

    We prepared and demonstrated a compact, simple-to-fabricate, air microcavity in polydimethylsiloxane (PDMS) placed at the end of a single-mode optical fibre. This microcavity creates a Fabry-Perot interferometer sensor able to measure concentrations of toluene vapour in air. Operation of the sensor is provided by diffusion of the toluene vapour to the PDMS, and the consequent extension of length d of the air microcavity in PDMS. The sensor response for the presence of vapours is fast and occurs within a few seconds. By using the prepared sensor toluene vapour concentration in air can be measured in the range from about 0.833 g.m-3 to saturation, with better sensitivity than 0.15 nm/g.m-3 up to maximal sensitivity 1.4 nm/g.m-3 at around concentration 100 g.m-3 in time 5 s.

  4. Optical fibre line failure detecting

    OpenAIRE

    Xie, Feng

    2013-01-01

    With the development of modern communications, in order to meet the needs of social development and technological progress the optical fibre communications has become the main communication medium for its high reliability and security. Fibre-optic cable is the channel for signal transmission. It is an important component in the entire fibre-optic network. Once the fibre-optic cable fault happened, the entire communication system would be impacted seriously. When fault occurs, it is important ...

  5. Fibre Optics in Undersea Applications

    Directory of Open Access Journals (Sweden)

    A. K. Talwar

    1984-01-01

    Full Text Available Role of optical fibres for underwater communication cables and hydrophones is discussed. The fibre optics cables provide an excellent solution to the historical bandwidth-diameter problems of conventional coaxial cables.Fibre optic hydrophones are found to have many more advantages apart from high sensitivity and large dynamic range, over the classical sound sensors used in underwater work.

  6. 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

    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...... 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...

  7. Tapered optical fibres for sensing

    Science.gov (United States)

    Martan, Tomas; Kanka, Jiri; Kasik, Ivan; Matejec, Vlastimil

    2008-11-01

    Recently, optical fibre tapers have intensively been investigated for many applications e.g. in telecommunications, medicine and (bio-) chemical sensing. The paper deals with enhancement of evanescent-field sensitivity of the solid-core microstructured fibre with steering-wheel air-cladding. Enhancement of a performance of the microstructured fibre is based on reduction of fibre core diameter down to narrow filament by tapering thereby defined part of light power is guided by an evanescent wave traveling in axial cladding air holes. The original fibre structure with outer diameter of 125 µm was reduced 2×, 2.5×, 3.33×, and 4× for increasing relatively small intensity overlap of guided core mode at wavelength of 1.55 μm with axial air holes. The inner structures of tapered microstructured fibre with steering-wheel aircladding were numerically analyzed and mode intensity distributions were calculated using the FDTD technique. Analyzed fiber tapers were prepared by constructed fibre puller employing 'flame brush technique'.

  8. 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...

  9. Chemical detection in liquid media with a refractometric sensor based on a multimode optical fibre

    OpenAIRE

    V. Matejec; Jaffrezic-Renault, N.; Abdelghani, A.; S. Hleli; Cherif, K

    2002-01-01

    In this paper the physical basis for the design of an optical fibre sensor suited for aqueous medium and gas phase based on the excitation of an evanescent wave at the core/cladding interface is developed. The detection based on the refractive index changes (between 1.41 and 1.45) of the infinite dielectric medium which can be an electrolyte or a sol-gel polymer deposited on the uncladed part of the fibre. Refractive indices of absorbent and volatile compounds such as fuel and unleaded gas we...

  10. Surface plasmon resonance based fibre optic chemical sensor for the detection of cocaine

    Science.gov (United States)

    Nguyen, T. Hien; Sun, Tong; Grattan, Kenneth T. V.

    2016-05-01

    A surface plasmon based fibre-optic chemical sensor for the detection of cocaine has been developed using a molecularly imprinted polymer (MIP) film with embedded gold nanoparticles as the recognition element. The MIP was formed on the layer of gold thin film which was deposited on the surface of a fibre core. The sensing was based on swelling of the MIP film induced by analyte binding that shifted the resonance spectrum toward a shorter wavelength. The sensor exhibited a response to cocaine in the concentration range of 0 - 400 μM in aqueous acetonitrile mixtures. Selectivity for cocaine over other drugs has also been demonstrated.

  11. Glucose optical fibre sensor based on a luminescent molecularly imprinted polymer

    Science.gov (United States)

    Elosua, C.; Wren, S. P.; Sun, T.; Arregui, F. J.; Grattan, Kenneth T. V.

    2015-09-01

    An optrode able to detect glucose dissolved in water has been implemented. The device is based on the luminescence emission of a Molecularly Imprinted Polymer synthesized specifically for glucose detection, therefore its intensity changes in presence of glucose. This sensing material is attached onto a cleaved ended polymer-clad optical fibre and it is excited by light via 1x2 fibre coupler. The reflected fluorescence signal increases when it is immersed into glucose solutions and recovers to the baseline when it is dipped in ultrapure water. This reversible behaviour indicates the measurement repeatability of using such a glucose sensor.

  12. Secure Communication System Based on Chaos in Optical Fibre

    Institute of Scientific and Technical Information of China (English)

    Pak; L; Chu; Fan; Zhang; William; Mak; Robust; Lai

    2003-01-01

    1 IntroductionRecently, there have been intense research activities on the study of synchronized chaos generated by fibre lasers and its application to secure communication systems. So far, all studies concentrate on two aspects: (1) the effect of the transmission channel between the transmitter and the receiver has been neglected, and (2) the chaos and the signal are carried by one wavelength. Both theoretical and experimental investigations make

  13. 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...

  14. 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...

  15. Threshold temperature optical fibre sensors

    Science.gov (United States)

    Stasiewicz, K. A.; Musial, J. E.

    2016-12-01

    This paper presents a new approach to manufacture a threshold temperature sensor based on a biconical optical fibre taper. The presented sensor employs the influence of variable state of concentration of some isotropic materials like wax or paraffin. Application of the above- mentioned materials is an attempt to prove that there is a possibility to obtain a low-cost, repeatable and smart sensor working as an in-line element. Optical fibre taper was obtained from a standard single mode fibre (SMF28®) by using a low pressure gas burner technique. The diameter of the manufactured tapers was 6.0 ± 0.5 μm with the length of elongation equal to 30.50 ± 0.16 mm. The applied technology allowed to produce tapers with the losses of 0.183 ± 0.015 dB. Application of materials with different temperature transition points made it possible to obtain the threshold work at the temperatures connected directly with their conversion temperature. External materials at the temperatures above their melting points do not influence the propagation losses. For each of them two types of the protection area and position of the optical fibre taper were applied.

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

    Science.gov (United States)

    Aiestaran, Pedro; Arrue, Jon; Zubia, Joseba

    2009-01-01

    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.

  17. 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.

  18. Chemical detection in liquid media with a refractometric sensor based on a multimode optical fibre

    Directory of Open Access Journals (Sweden)

    V. Matejec

    2002-06-01

    Full Text Available In this paper the physical basis for the design of an optical fibre sensor suited for aqueous medium and gas phase based on the excitation of an evanescent wave at the core/cladding interface is developed. The detection based on the refractive index changes (between 1.41 and 1.45 of the infinite dielectric medium which can be an electrolyte or a sol-gel polymer deposited on the uncladed part of the fibre. Refractive indices of absorbent and volatile compounds such as fuel and unleaded gas were determined. Using a xerogel sensing layer as optical cladding, toluene detection in water was performed. The observed sensitivity is linear and the detection limit is 1% (in volume toluene in water.

  19. Microcontroller based fibre-optic visual presentation system for multisensory neuroimaging.

    Science.gov (United States)

    Kurniawan, Veldri; Klemen, Jane; Chambers, Christopher D

    2011-10-30

    Presenting visual stimuli in physical 3D space during fMRI experiments carries significant technical challenges. Certain types of multisensory visuotactile experiments and visuomotor tasks require presentation of visual stimuli in peripersonal space, which cannot be accommodated by ordinary projection screens or binocular goggles. However, light points produced by a group of LEDs can be transmitted through fibre-optic cables and positioned anywhere inside the MRI scanner. Here we describe the design and implementation of a microcontroller-based programmable digital device for controlling fibre-optically transmitted LED lights from a PC. The main feature of this device is the ability to independently control the colour, brightness, and timing of each LED. Moreover, the device was designed in a modular and extensible way, which enables easy adaptation for various experimental paradigms. The device was tested and validated in three fMRI experiments involving basic visual perception, a simple colour discrimination task, and a blocked multisensory visuo-tactile task. The results revealed significant lateralized activation in occipital cortex of all participants, a reliable response in ventral occipital areas to colour stimuli elicited by the device, and strong activations in multisensory brain regions in the multisensory task. Overall, these findings confirm the suitability of this device for presenting complex fibre-optic visual and cross-modal stimuli inside the scanner.

  20. Optical fibre multi-parameter sensing with secure cloud based signal capture and processing

    Science.gov (United States)

    Newe, Thomas; O'Connell, Eoin; Meere, Damien; Yuan, Hongwei; Leen, Gabriel; O'Keeffe, Sinead; Lewis, Elfed

    2016-05-01

    Recent advancements in cloud computing technologies in the context of optical and optical fibre based systems are reported. The proliferation of real time and multi-channel based sensor systems represents significant growth in data volume. This coupled with a growing need for security presents many challenges and presents a huge opportunity for an evolutionary step in the widespread application of these sensing technologies. A tiered infrastructural system approach is adopted that is designed to facilitate the delivery of Optical Fibre-based "SENsing as a Service- SENaaS". Within this infrastructure, novel optical sensing platforms, deployed within different environments, are interfaced with a Cloud-based backbone infrastructure which facilitates the secure collection, storage and analysis of real-time data. Feedback systems, which harness this data to affect a change within the monitored location/environment/condition, are also discussed. The cloud based system presented here can also be used with chemical and physical sensors that require real-time data analysis, processing and feedback.

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

    Indian Academy of Sciences (India)

    T Kundu; V V R Sai; R Dutta; S Titas; P Kumar; S Mukherjee

    2010-12-01

    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 analytes such as bacteria, virus and some clinically important proteins. A simple UV-LED (280 nm) and photodetector combination along with a fibre probe was used for developing cost-effective, user-friendly and field applicable device. To improve the sensitivity of the detection technique, the probe design was modified and the U-bent probe was fabricated by simple procedure. Further, to overcome the problems for using UV light source in 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 for house-hold as well as field applications.

  3. Fibre-optic nonlinear optical microscopy and endoscopy.

    Science.gov (United States)

    Fu, L; Gu, M

    2007-06-01

    Nonlinear optical microscopy has been an indispensable laboratory tool of high-resolution imaging in thick tissue and live animals. Rapid developments of fibre-optic components in terms of growing functionality and decreasing size provide enormous opportunities for innovations in nonlinear optical microscopy. Fibre-based nonlinear optical endoscopy is the sole instrumentation to permit the cellular imaging within hollow tissue tracts or solid organs that are inaccessible to a conventional optical microscope. This article reviews the current development of fibre-optic nonlinear optical microscopy and endoscopy, which includes crucial technologies for miniaturized nonlinear optical microscopy and their embodiments of endoscopic systems. A particular attention is given to several classes of photonic crystal fibres that have been applied to nonlinear optical microscopy due to their unique properties for ultrashort pulse delivery and signal collection. Furthermore, fibre-optic nonlinear optical imaging systems can be classified into portable microscopes suitable for imaging behaving animals, rigid endoscopes that allow for deep tissue imaging with minimally invasive manners, and flexible endoscopes enabling imaging of internal organs. Fibre-optic nonlinear optical endoscopy is coming of age and a paradigm shift leading to optical microscope tools for early cancer detection and minimally invasive surgery.

  4. Resonance modes in optical fibres

    Institute of Scientific and Technical Information of China (English)

    余寿绵; 余恬

    2002-01-01

    The weakly nonlinear boundary value problem of wave propagation in an optical fibre (for the transverse electric mode, for example) is formulated and a modified linear solution is obtained. It is shown that a self-consistent theory of fibre optics should be weakly nonlinear. The mode of critical refraction that does not exist in the linear theory is obtained, showing that it is a mode consisting of resonance modes. It is shown that the signal carriers in a long fibre are of resonance modes, not normal modes. Some experimental data are given for comparison with the theoretical predictions, and the agreement seems satisfactory.

  5. 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.

  6. 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.

  7. 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

    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......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......-inscribed and characterised with regard their stress and force sensitivities. Then, the fibres were annealed by placing them in hot water, controlling with that way the humidity factor. After annealing, stress and force sensitivities were measured again. The results show that the annealing can improve the stress and force...

  8. Terbium-doped gadolinium oxysulfide (Gd2O2S:Tb) scintillation-based polymer optical fibre sensor for real time monitoring of radiation dose in oncology

    Science.gov (United States)

    Lewis, E.; O'Keeffe, S.; Grattan, M.; Hounsell, A.; McCarthy, D.; Woulfe, P.; Cronin, J.; Mihai, L.; Sporea, D.; Santhanam, A.; Agazaryan, N.

    2014-05-01

    A PMMA based plastic optical fibre sensor for use in real time radiotherapy dosimetry is presented. The optical fibre tip is coated with a scintillation material, terbium-doped gadolinium oxysulfide (Gd2O2S:Tb), which fluoresces when exposed to ionising radiation (X-Ray). The emitted visible light signal penetrates the sensor optical fibre and propagates along the transmitting fibre at the end of which it is remotely monitored using a fluorescence spectrometer. The results demonstrate good repeatability, with a maximum percentage error of 0.5% and the response is independent of dose rate.

  9. Underwater Acoustic Sensing with Optical Fibres

    Directory of Open Access Journals (Sweden)

    V. V. Rampal

    1982-01-01

    Full Text Available The use of optical fibres for the detection of acoustic pressure underwater has been discussed with particular reference to the recent literature on the development of fibre optic hydrophones.

  10. Theoretical modelling of a bi-dimensional U-shaped surface plasmon resonance based fibre optic sensor for sensitivity enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Verma, R K; Gupta, B D [Physics Department, Indian Institute of Technology Delhi, New Delhi-110016 (India)], E-mail: bdgupta@physics.iitd.ernet.in

    2008-05-07

    Theoretical analysis of a surface plasmon resonance based fibre optic sensor with a uniform semi-metal coated U-shaped probe is carried out using a bi-dimensional model. All the rays of the p-polarized light launched in the fibre and their electric vectors are assumed to be confined in the plane of bending of the U-shaped probe. The effect of the bending radius of the probe on the sensitivity of the sensor is studied. The study shows that as the bending radius of the probe decreases the sensitivity of the sensor increases. For the light launching conditions used, the maximum sensitivity achieved is several times more than that reported for a fibre optic tapered probe. In addition to high sensitivity, the most advantageous feature of a U-shaped probe is that it can be used as a point sensor.

  11. Microstructure-Fibre-Based Optical Parametric Amplification in Telecom Band with Ultra-High Gain Slope

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei; XIAO Li; ZHANG Lei; HUANG Yi-Dong; PENG Jiang-De

    2006-01-01

    @@ We report a microstructure-fibre-based parametric amplification experiment in telecom band with ultra-high gain slope. A peak on-off gain of 52.3 dB is achieved using 25 m high nonlinear microstructure fibre (MF) and only 5.3 W pump power. The parametric gain slope is up to 580dBW-1 km-1. From the experimental data, the linear coefficient of the MF is estimated to be about 66. 7 W-1 km-1. The experiment shows the great potential of MFs in practical fibre parametric amplifiers.

  12. 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...

  13. Wavelength Filters in Fibre Optics

    CERN Document Server

    Venghaus, Herbert

    2006-01-01

    Wavelength filters constitute an essential element of fibre-optic networks. This book gives a comprehensive account of the principles and applications of such filters, including their technological realisation. After an introductory chapter on wavelength division multiplexing in current and future fibre optic networks follows a detailed treatment of the phase characteristics of wavelength filters, a factor frequently neglected but of significant importance at high bit rates. Subsequent chapters cover three-dimensional reflection of gratings, arrayed waveguide gratings, fibre Bragg gratings, Fabry-Perot filters, dielectric multilayer filters, ring filters, and interleavers. The book explains the relevant performance parameters, the particular advantages and shortcomings of the various concepts and components, and the preferred applications. It also includes in-depth information on the characteristics of both commercially available devices and those still at the R&D stage. All chapters are authored by inter...

  14. 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

  15. Optical fibre cantilever sensor for biological application

    Science.gov (United States)

    Li, J.; Zhou, Y. X.; Patterson, G.; Shu, W. M.; Maier, R. R. J.; Fowler, R.; Hand, D. P.; MacPherson, W. N.

    2014-05-01

    Micro-cantilever sensors have shown great promise in a wide range of application are as including chemical and biological sensing. However, many of these devices are based upon a sensor `chip' that requires careful alignment between the cantilever and the read-out system, which can be challenging. Furthermore, optical interrogation typically involves a bulky free-space system. Optical fibre addressed cantilevers have been reported previously in the literature and in this paper we propose techniques to design and fabricate polymer micro-cantilevers for attachment onto the end of standard single mode fibres using laser machining. Low-cost optical sources and a fibre coupled spectrometer are employed to monitor the cantilever deflection and therefore observe biological binding between a species of interest and an activated cantilever. Proof-of-concept experiments show that the sensor is capable of detecting pathogen concentration with down to a level of 105cfu/ml.

  16. Optical fibre Fabry-Perot relative humidity sensor based on HCPCF and chitosan film

    Science.gov (United States)

    Liu, Xiaohui; Jiang, Mingshun; Sui, Qingmei; Geng, Xiangyi

    2016-09-01

    An optical fibre Fabry-Perot interferometer (FPI) sensor for relative humidity (RH) measurement is proposed. The FPI is formed by splicing a short section of hollow-core photonic crystal fibre(HCPCF) to single mode fibre and covering a chitosan film at the end of HCPCF. The refractive index of chitosan and film thickness will change with ambient RH, leading to the change in the reflected interference spectrum of FPI. RH response of the FPI sensor is analysed theoretically and demonstrated experimentally. It shows nonlinear response to RH values from 35 to 95%RH. The interference fringe shifts to shorter wavelength as RH increases with a maximum sensitivity of 0.28 nm/%RH at high RH level. And the fringe contrast also decreases as RH increases with an available maximum sensitivity of 0.5 dB/%RH. The sensor shows good stability and fast response time less than 1 min. With its advantages of compact structure, good performance, simple and safe fabrication, the proposed optical fibre FPI sensor has great potential for RH sensing.

  17. A model of the mammalian optic nerve fibre based on experimental data.

    Science.gov (United States)

    Oozeer, M; Veraart, C; Legat, V; Delbeke, J

    2006-08-01

    Several experimental data about membrane dynamics and pharmacological sensitivities of optic nerve axons have been published. The present work summarizes these data and computer simulations have been used to develop a model of the mammalian optic nerve fibre. The ionic currents description were derived from existing membrane models and particularly from a model of the somatic retinal ganglion cell (RGC) impulse generation. However, original equations had to be modified to match experimental data, which suggests that in RGCs, axonal and somatic ion channel expression are different. The new model is consistent with recent experimental results about optic nerve axonal excitability.

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

    Science.gov (United States)

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

    2015-09-01

    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 and acetic acid.

  19. Direct and rapid discrimination of aflatoxigenic strains based on fibre-optic room temperature phosphorescence detection.

    Science.gov (United States)

    Rojas-Durán, T; Sánchez-Barragán, I; Costa-Fernández, J M; Sanz-Medel, A

    2007-04-01

    An innovative analytical methodology for the rapid identification of aflatoxin-producing moulds belonging to Aspergillus genus is presented here. The procedure is based on the measurement, using a fibre-optic luminometer, of the room temperature phosphorescence (RTP) emitted by aflatoxins produced by isolated aflatoxigenic strains, cultured in a special culture medium consisting of malt extract agar modified with beta-cyclodextrin and sodium deoxycholate for RTP induction. Unequivocal detection of the presence of aflatoxins in the culture medium is achieved within the first 36 h of incubation at 32 degrees C, owing to the selectivity and sensitivity of the RTP emission, as compared with the minimum of 72 h needed using a conventional microbiological method. In a first step, the capability of aflatoxin standard solutions to emit analytically useful RTP was evaluated. In this line all experimental conditions were optimised for in vitro induction of RTP from aflatoxins. In a second step, a simple analytical test was developed and it has been evaluated for the rapid identification of aflatoxigenic strains, as a discriminating assay from non-aflatoxigenic strains based on the measurement of experimental RTP emission observed. Confirmation of aflatoxin production on the studied culture plates was accomplished by means of an HPLC/fluorescence reference method.

  20. Optical fibre bragg gratings based magnetic force measurement of magnetic bearings

    Science.gov (United States)

    Ding, Guoping; Zhou, Zude; Hu, Yefa; Zhou, Jianhua

    2008-12-01

    Magnetic bearings are typical electromechanical systems of high performance. Current-displacement-force relationship between stator and rotor is an important research topic of magnetic bearings. The critical issue is to realize magnetic force online dynamic measurement. This paper presents a novel method on magnetic force measurement of magnetic bearings with optical fibre bragg gratings (FBG), which realizes a non-contact and online force measurement with simple configuration, good noise immunity even when the rotor is running. A novel micro force transducer is designed and fabricated, which is mounted within the stator magnetic pole. To obtain current-displacement-force relationship a FBG based magnetic force measurement test rig is setup to simulate magnetic bearing working states as the stator coils currents, air gap between stator and rotor, rotor speed is adjustable. Magnetic force is measured under three classifications of test conditions and test results are presented. The measurement data show good consistency with the theory analysis and calculation, which means that the FBG based magnetic force measurement is available and of good accuracy.

  1. Optical Fibre Dosimeter for SASE FEL Undulators

    CERN Document Server

    Körfer, M

    2003-01-01

    Single pass Free Electron Lasers (FELs) based on self-amplified spontaneous emission (SASE) are developed for high brightness and short wavelength applications. They use permanent magnet undulators which are radiation sensitive devices. During accelerator commissioning beam losses can appear anywhere along the undulator line. To avoid damage of the permanent magnets due to radiation, an optical fibre dosimeter system can be used. The increase of absorption caused by ionizing radiation is measured in radiation sensitive optical fibers. The dose system enables relatively fast particle loss tuning during accelerator operation and allows the monitoring of the accumulated dose. Dose measurements in narrow gaps which are inaccessible for any other (online) dosimeter type become possible. The electromagnetic insensitivity of optical fibre sensor is an advantage of applications in strong magnetic undulator fields. At each location the light absorption is measured by using an optical power-meter. The dynamic range is ...

  2. Initial research of dual wavelength fibre optic perimeter sensor

    Science.gov (United States)

    Zyczkowski, M.; Kondrat, M.; Ciurapinski, W.

    2005-10-01

    The dual wavelength fibre optic perimeter sensor bases on input signals measurements in an arrangement of fibre optic Michelson and Sagnac interferometers with a 3 × 3 coupler and two semiconductor lasers. For 3 km long sensor we obtained 20-50m resolution of determination of disturbance point.

  3. Nonlinear fibre optics overview

    DEFF Research Database (Denmark)

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

    2010-01-01

    , provides a background to the associated nonlinear optical processes, treats the generation mechanisms from continuous wave to femtosecond pulse pump regimes and highlights the diverse applications. A full discussion of numerical methods and comprehensive computer code are also provided, enabling readers...

  4. 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.

  5. 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

  6. Performance analysis of polymer optical fibre based Fabry-Perot sensor formed by two uniform Bragg gratings

    Science.gov (United States)

    Pospori, A.; Webb, D. J.

    2016-04-01

    The stress sensitivity of polymer optical fibre (POF) based Fabry-Perot sensors formed by two uniform Bragg gratings with finite dimensions is investigated. POF has received high interest in recent years due to its different material properties compared to its silica counterpart. Biocompatibility, a higher failure strain and the highly elastic nature of POF are some of the main advantages. The much lower Young's modulus of polymer materials compared to silica offers enhanced stress sensitivity to POF based sensors which renders them great candidates for acoustic wave receivers and any kind of force detection. The main drawback in POF technology is perhaps the high fibre loss. In a lossless fibre the sensitivity of an interferometer is proportional to its cavity length. However, the presence of the attenuation along the optical path can significantly reduce the finesse of the Fabry-Perot interferometer and it can negatively affect its sensitivity at some point. The reflectivity of the two gratings used to form the interferometer can be also reduced as the fibre loss increases. In this work, a numerical model is developed to study the performance of POF based Fabry-Perot sensors formed by two uniform Bragg gratings with finite dimensions. Various optical and physical properties are considered such as grating physical length, grating effective length which indicates the point where the light is effectively reflected, refractive index modulation of the grating, cavity length of the interferometer, attenuation and operating wavelength. Using this model, we are able to identify the regimes in which the PMMA based sensor offer enhanced stress sensitivity compared to silica based one.

  7. Bragg grating-based fibre optic sensors in structural health monitoring.

    Science.gov (United States)

    Todd, Michael D; Nichols, Jonathan M; Trickey, Stephen T; Seaver, Mark; Nichols, Christy J; Virgin, Lawrence N

    2007-02-15

    This work first considers a review of the dominant current methods for fibre Bragg grating wavelength interrogation. These methods include WDM interferometry, tunable filter (both Fabry-Perot and acousto-optic) demultiplexing, CCD/prism technique and a newer hybrid method utilizing Fabry-Perot and interferometric techniques. Two applications using these techniques are described: hull loads monitoring on an all-composite fast patrol boat and bolt pre-load loss monitoring in a composite beam in conjunction with a state-space modelling data analysis technique.

  8. A simple pendulum borehole tiltmeter based on a triaxial optical-fibre displacement sensor

    Science.gov (United States)

    Chawah, P.; Chéry, J.; Boudin, F.; Cattoen, M.; Seat, H. C.; Plantier, G.; Lizion, F.; Sourice, A.; Bernard, P.; Brunet, C.; Boyer, D.; Gaffet, S.

    2015-11-01

    Sensitive instruments like strainmeters and tiltmeters are necessary for measuring slowly varying low amplitude Earth deformations. Nonetheless, laser and fibre interferometers are particularly suitable for interrogating such instruments due to their extreme precision and accuracy. In this paper, a practical design of a simple pendulum borehole tiltmeter based on laser fibre interferometric displacement sensors is presented. A prototype instrument has been constructed using welded borosilicate with a pendulum length of 0.85 m resulting in a main resonance frequency of 0.6 Hz. By implementing three coplanar extrinsic fibre Fabry-Perot interferometric probes and appropriate signal filtering, our instrument provides tilt measurements that are insensitive to parasitic deformations caused by temperature and pressure variations. This prototype has been installed in an underground facility (Rustrel, France) where results show accurate measurements of Earth strains derived from Earth and ocean tides, local hydrologic effects, as well as local and remote earthquakes. The large dynamic range and the high sensitivity of this tiltmeter render it an invaluable tool for numerous geophysical applications such as transient fault motion, volcanic strain and reservoir monitoring.

  9. 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.

  10. Broadly Tunable SOA-Based Active Mode-Locked Fibre Ring Laser by Forward Injection Optical Pulse

    Institute of Scientific and Technical Information of China (English)

    YAN Shuang-Yi; ZHANG Jian-Guo; ZHAO Wei; LU Hong-Qiang; WANG Wei-Qiang

    2008-01-01

    @@ We present a broadly tunable active mode-locked fibre ring laser based on a semiconductor optical amplifier (SOA), with forward injection optical pulses. The laser can generate pulse sequence with pulsewidth about 12ps and high output power up to 8.56dBm at 2.5 GHz stably. Incorporated with a wavelength-tunable optical bandpass filter, the pulse laser can operate with a broad wavelength tunable span up to 37nm with almost constant pulsewidth. A detailed experimental analysis is also carried out to investigate the relationship between the power of the internal cavity and the pulsewidth of the output pulse sequence. The experimental configuration of the pulse laser is very simple and easy to setup with no polarization-sensitive components.

  11. 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...

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

    Science.gov (United States)

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

    2014-07-01

    We describe an attempt at the utilisation of two low level light sensors to improve on the design of a dose monitoring system, specifically for underwater applications with consideration for the effects of water attenuation. The gamma radiation ‘RadLine®’ detector consists of an inorganic scintillating crystal coupled to a fibre optic cable which transports scintillation photons, up to hundreds of metres, to an optical sensor. Analysed here are two contemporary technologies; SensL's MiniSL a silicon photomultiplier (SiPM) and a Sens-Tech photon counting photomultiplier tube (PMT). A clinical radiotherapy linear accelerator (linac) is implemented as test beam, subjecting the RadLine® to a highly controlled dose rate (ranging from 0 Sv h-1 to 320 Sv h-1), averaging at 2 MeV in energy. The RadLine's underwater dose monitoring capabilities are tested with the aid of epoxy resin ‘solid water’ phantom blocks, used as a substitute for water. Our results show that the MiniSL SiPM is unsuitable for this application due to extremely high background noise levels, however the Sens-Tech PMT performs satisfactorily and the detected dose rate due to the effects of water attenuation compares strongly with MCNP simulation data and NIST database values. We conclude that the PMT shows promise for its ultimate use in the First Generation Magnox Storage Pond (FGMSP) on the Sellafield site.

  13. Fibre Optic Protection System for Concrete Structures

    Institute of Scientific and Technical Information of China (English)

    J.S.Leng; A.Hameed; D.Winter; R.A.Barnes; G.C.Mays; G.F.Fernando

    2006-01-01

    The design concepts, modelling and implementation of various fibre optic sensor protection systems for development in concrete structures were investigated. Design concepts and on-site requirements for surface-mounted and embedded optical fibre sensor in concrete were addressed. Finite element (FE) modelling of selected sensor protection systems in strain-transfer efficiency from the structure to the sensing region was also studied. And experimental validation of specified sensor protection system was reported. Results obtained indicate that the protection system for the sensors performs adequately in concrete environment and there is very good correlation between results obtained by the protected fibre optic sensors and conventional electrical resistance strain gauges.

  14. The development of fibre optic microbend sensors

    NARCIS (Netherlands)

    Horsthuis, W.H.G.; Fluitman, J.H.J.

    1983-01-01

    Investigations concerning the development of a fibre optic pressure sensor are reported. The phenomenon of light power attenuation in a periodically deformed graded index fibre has been studied theoretically. It appears that available theories are not suited to describe this attenuation process in t

  15. 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.

  16. Embedding of fibre optic sensors within flexible host

    OpenAIRE

    Ferraris, Eleonora; Van Gijseghem, Tim; Yan, Chunxiao; Van Hoe, Bram; Van Steenberge, Geert; Van Daele, Peter; Dubruel, Peter; Reynaerts, Dominiek

    2009-01-01

    This work deals with the establishment of a UV polymerisation procedure combined with moulding technology towards the development of a mass production technology for the fabrication of flexible polymers with optical fibres embedded. The concept is to provide an artificial sensing skin based on fibre optic sensors which can be applied to irregular or moveable surfaces for distributed pressure applications, as for instance in structural monitoring or rehabilitation. The selected polymers for su...

  17. Note: A concrete erosion sensor based on a chirped fibre optic Bragg grating.

    Science.gov (United States)

    Kanopoulos, Patrick; Xia, Kaiwen; Gu, Xijia; Amirchoupani, Ardavan; Yao, Wei

    2015-12-01

    Erosion of concrete surfaces in major civil structures is a common problem, which in certain circumstances can undermine the structural and operational integrities of the structure. The manual monitoring of the erosion process can be difficult and dangerous under certain circumstances (such as within hydrotunnels and spillways of dams). This paper describes a concrete erosion sensor based on a chirped fibre Bragg grating (FBG) which is able to monitor the extent of concrete erosion at a single point to sub-millimetre accuracy. The chirped FBG length embedded below the concrete surface decreases as a result of concrete erosion and consequently the reflected light spectrum bandwidth narrows. A simple procedure is presented to determine the extent of erosion, and this procedure is applied to an experimental demonstration of the sensing device.

  18. 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.

  19. Effects of Polarization-Maintaining Fibre Degrading on Precision of Fibre Optic Gyroscopes in Radiation Environment

    Institute of Scientific and Technical Information of China (English)

    XIAO Wen; LIU De-Wen; LIU Yang; YI Xiao-Su; CONG Lin

    2008-01-01

    @@ In the space environment, the precision of fibre optic gyroscopes (FOGs) degrades because of space radiation.Photonic components of FOGs axe affected by radiation, especially the polaxization-maintaining (PM) fibre coil.In relation to the space radiation environment characteristic, we have carried out a series of radiation experiments on a PM fibre coil with 60Co radiation source at different dose rates. Based on the experimental results, the formula between the PM-fibre loss and radiation dose rata is built, and the relation between the precision of FOG and radiation dose is obtained accordingly. The results strongly show that the precision of our FOG degrades owing to the attenuation of the polarization-maintaining fibre, which provides theoretical foundation for the radiation-resistant design of the FOG.

  20. Fibre-optic sensors in health care

    Science.gov (United States)

    Grazia Mignani, Anna; Baldini, Francesco

    1997-05-01

    Biomedical fibre-optic sensors are attractive for the measurement of physical, chemical and biochemical parameters and for spectral measurements directly performed on the patient. An overview of fibre-optic sensors for in vivo monitoring is given, with particular attention paid to the advantages that these sensors are able to offer in different application fields such as cardiovascular and intensive care, angiology, gastroenterology, ophthalmology, oncology, neurology, dermatology and dentistry.

  1. A multi-purpose optical fibre sensor design for fibre reinforced composite materials

    Science.gov (United States)

    Fernando, G. F.; Liu, T.; Crosby, P.; Doyle, C.; Martin, A.; Brooks, D.; Ralph, B.; Badcock, R.

    1997-10-01

    This paper reports on the evaluation of a multi-functional extrinsic Fabry - Pérot optical fibre-based sensor design. The sensor was constructed using multimode and single mode optical fibres and a precision bore capillary tube. Fusion joints were used to secure the optical fibres into the capillary tube. The separation between the cleaved end-faces of the optical fibres defined the cavity length for the Fabry - Pérot sensor and the distance between the fusion joints defined the gauge length for this strain and temperature sensor. The sensor design was modified to: (i) monitor the progress of cure in an epoxy/amine resin system; (ii) detect the ingress of moisture in a cured epoxy/amine resin system; (iii) monitor the vibration characteristics of a pre- and post-impact damaged carbon fibre reinforced epoxy panel; and (iv) discriminate between strain and temperature measurements. The feasibility of using this type of sensor for cure monitoring, strain, temperature, residual stress measurements and damage detection in advanced fibre reinforced composites is demonstrated.

  2. Economics Of Optical Fibre Transmission Systems

    Science.gov (United States)

    Murray, W. J.

    1983-08-01

    Optical fibre as a telecommunication transmission medium has become one of the most significant developments so far of the digital era. A major contributory factor to the availability of optical fibre transmission systems has been the outstanding progress in the technology of manufacturing high quality glass fibre having relatively low attenuation and broad bandwidths. This and other achievements has enabled manufacturers in the United Kingdom to develop a range of optical fibre cables and transmission equipment for operation over short and long distances at the CCITT recommended digital hierarchical rates of 2, 8, 34 and 140Mbit/s which have been adopted by British Telecom (BT) for modernisation to an all digital transmission network. These optical fibre systems are now becoming increasingly price and performance competitive with conventional technology in many parts of telecommunications networks. In the British Telecom (BT) network the 140Mbit/s optical fibre systems are now economically competitive with equivalent systems on coaxial cable and microwave radio. The economics of 8 and 34Mbit/s systems are not yet sufficiently attractive, compared with 2Mbit/s digital line systems on pair type copper cables, for large scale use in rural and local distribution networks and are presently only justified on cost in and around large cities. As system costs decrease large applications are predicted particularly in support of future high speed data, cable television and visual information services.

  3. Simulation of complex phenomena in optical fibres

    CERN Document Server

    Allington-Smith, Jeremy; Lemke, Ulrike

    2012-01-01

    Optical fibres are essential for many types of highly-multiplexed and precision spectroscopy. The success of the new generation of multifibre instruments under construction to investigate fundamental problems in cosmology, such as the nature of dark energy, requires accurate modellisation of the fibre system to achieve their signal-to-noise goals. Despite their simple construction, fibres exhibit unexpected behaviour including non-conservation of Etendue (Focal Ratio Degradation; FRD) and modal noise. Furthermore, new fibre geometries (non-circular or tapered) have become available to improve the scrambling properties that, together with modal noise, limit the achievable SNR in precision spectroscopy. These issues have often been addressed by extensive tests on candidate fibres and their terminations but these are difficult and time-consuming. Modelling by ray-tracing and wave analysis is possible with commercial software packages but these do not address the more complex features, in particular FRD. We use a...

  4. Special Polymer Optical Fibres and Devices for Photonic Applications

    Institute of Scientific and Technical Information of China (English)

    Gang-Ding Peng

    2003-01-01

    Remarkable progresses have been made in developing special polymer optical fibres and devices for photonic applications in recent years. This presentation will mainly report on the development of electro-optic, photosensitive and photorefractive polymer optical fibres and related devices.

  5. Optimal Design of Dual-Pump Fibre-Optical Parametric Amplifiers with Dispersion Fluctuations Based on Hybrid Genetic Algorithm

    Institute of Scientific and Technical Information of China (English)

    LIU Xue-Ming; LI Yan-He

    2005-01-01

    @@ Solutions of dual-pump fibre-optical parametric amplifiers (DP-FOPAs) with dispersion fluctuations are derived by using a matrix operator. Based on these solutions and a hybrid genetic algorithm, we have optimized threesection DP-FOPAs to increase the signal band and improve the gain uniformity. The optimizations demonstrate that when dispersion fluctuations are taken into account, the 44-nm signal band with the 0.37-dB ripple and over 14.8-dB gain can be obtained from the three-section DP-FOPA, instead of the lowest gain of ~13dB with the ripple of more than 15dB from the single-section DP-FOPA.

  6. On the performance of surface plasmon resonance based fibre optic sensor with different bimetallic nanoparticle alloy combinations

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Anuj K; Mohr, Gerhard J [Institute of Physical Chemistry, Friedrich-Schiller University, Lessingstrasse 10, 07743 Jena (Germany)], E-mail: anuj.sharma@uni-jena.de

    2008-03-07

    In this work, we have investigated the capability of different bimetallic nanoparticle alloy combinations to be used in fibre optic sensors based on the technique of surface plasmon resonance. The metals considered for this analysis are silver, gold, copper and aluminium. The performance of the sensor with different bimetallic nanoparticle alloy combinations is evaluated and compared numerically. The performance is analysed in terms of three parameters: sensitivity, signal-to-noise ratio (SNR) and operating range for the sensing layer refractive index values. On the basis of the comparison and some logistic criteria, the best possible bimetallic alloy combinations along with a requisite alloy composition ratio are predicted. The bimetallic nanoparticle alloy combination is capable of simultaneously providing larger values of sensitivity, SNR and operating range, which is not possible with any single metallic nanoparticle layer.

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

    Science.gov (United States)

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

    2011-04-01

    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. Development of fibre-optic confocal microscopy for detection and diagnosis of dental caries.

    Science.gov (United States)

    Rousseau, C; Poland, S; Girkin, J M; Hall, A F; Whitters, C J

    2007-01-01

    We report on the development of a fibre-optics-based confocal imaging system for the detection and potential diagnosis of early dental caries. A novel optical instrument, capable of recording axial profiles through caries lesions using single-mode optical fibres, has been developed. The practical study illustrates that miniature confocal devices based around single-mode optical fibres may provide additional diagnostic information for the general dental practitioner.

  9. 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.

  10. Properties of Specialist Fibres and Bragg Gratings for Optical Fiber Sensors

    Directory of Open Access Journals (Sweden)

    John Canning

    2009-01-01

    Full Text Available The advent of optical fibres based on air holes running along their entirety opens up new directions in addressing various properties relevant to sensing, including the temperature/strain challenge of optical fibre sensors. This paper looks at the measurement challenges associated with temperature and strain, examines the potentially unique functionality structured fibre designs with and without gratings open up, and briefly describes some current research directions within conventional fibre and grating technologies.

  11. Optical fibre grating refractometers for resin cure monitoring

    Science.gov (United States)

    Buggy, S. J.; Chehura, E.; James, S. W.; Tatam, R. P.

    2007-06-01

    The use of fibre grating refractometers as a means of monitoring the cure of a UV-cured 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 × 10-3 rius) and illustrate the potential of the techniques for non-invasive composite material cure monitoring.

  12. Space Division Multiplexing in Optical Fibres

    CERN Document Server

    Richardson, D J; Nelson, L E

    2013-01-01

    Optical communications technology has made enormous and steady progress for several decades, providing the key resource in our increasingly information-driven society and economy. Much of this progress has been in finding innovative ways to increase the data carrying capacity of a single optical fibre. In this search, researchers have explored (and close to maximally exploited) every available degree of freedom, and even commercial systems now utilize multiplexing in time, wavelength, polarization, and phase to speed more information through the fibre infrastructure. Conspicuously, one potentially enormous source of improvement has however been left untapped in these systems: fibres can easily support hundreds of spatial modes, but today's commercial systems (single-mode or multi-mode) make no attempt to use these as parallel channels for independent signals.

  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...... poly-methyl-methacrylate (PMMA) based SIPOFs. The fibre has a minimum loss of similar to 6dB/m at 770nm....

  14. Development of an optical fibre reflectance sensor for p-aminophenol detection based on immobilised bis-8-hydroxyquinoline.

    Science.gov (United States)

    Filik, Hayati; Hayvali, Mustafa; Kiliç, Emine; Apak, Reşat; Aksu, Duygu; Yanaz, Zeynep; Cengel, Tayfun

    2008-10-19

    2,2'-(1,4-Phenylenedivinylene)bis-8-hydroxyquinoline (PBHQ), a highly sensitive reagent used for the colorimetric determination of p-aminophenol (PAP), was successfully immobilised on XAD-7 and coupled with optical fibres to investigate a sensor-based approach for determining p-aminophenol. The solid-state sensor is based on the reaction of PAP with PBHQ in presence of an oxidant to produce an indophenol dye. The reflectance measurements were carried out at a wavelength of 647 nm since it yielded the largest divergence different in reflectance spectra before and after reaction with the analyte. The linear dynamic range of PAP was found within the concentration range of 0.1-2.18 mg l(-1) with its LOD of 0.02 mg l(-1). The sensor response from different probes (n=7) gave a R.S.D. of 4.4% at 1.09 mg l(-1) PAP concentration. The response time of the optical one-shot sensor was 5 min for a stable solution. As this PAP sensor is irreversible, a fresh sensor has to be used for each measurement. All the experimental parameters were optimized for the determination of PAP. Using the optical sensing probe, PAP in pharmaceutical wastewater and paracetamol was determined. The effect of potential interferences such as inorganic and organic compounds was also evaluated. Potential on-site determination of PAP with such sensors can indirectly aid detection of organo-phosphorus nerve agents and pesticides in the field by inhibition of acetylcholine esterase-catalyzed hydrolysis of p-aminophenyl acetate to p-aminophenol.

  15. Implementation and characterization of a fibre-optic colour sensor

    Science.gov (United States)

    Bajić, Jovan S.; Stupar, Dragan Z.; Dakić, Bojan M.; Manojlović, Lazo M.; Slankamenac, Miloš P.; Živanov, Miloš B.

    2014-09-01

    In this paper the implementation of a fibre-optic sensor for colour detection based on reflective colour sensing is proposed. The sensor consists of three plastic optical fibres emitting red, green and blue components and one optical fibre collecting light reflected from the object. Red, green and blue LEDs are excited at different frequencies. In this way detection of the reflected signal is achieved with only one photodetector and three bandpass filters. Bandpass filters are implemented as digital IIR (infinite impulse response) filters on the microcontroller. Results obtained from the proposed sensor are compared with commercial available colour sensors and the results are satisfactory. Analyses of the sensor performance both in RGB and HSV colour space are done. The proposed solution shows that in specific applications by using the HSV model the sensor can be used both as a colour and distance sensor.

  16. Photothermal determination of optical coefficients using an optical fibre sensor

    CERN Document Server

    Laufer, J

    2000-01-01

    configuration is more sensitive to the thermal coefficients than the optical coefficients of the target. Pulsed photothermal radiometry was found to have higher sensitivity to the optical coefficients than has the optical fibre sensor in its present form. However, modifications to the configuration of the sensor can produce a performance matching that of pulsed photothermal radiometry. This thesis is concerned with the development of an optical fibre sensor for the photothermal determination of the optical coefficients of tissue. The detection of differences in tissue optical properties might be used for the diagnosis of cancers and other tissue pathologies. The sensor consists of a thin transparent polymer film mounted at the distal end of an optical fibre. The film acts as a Fabry-Perot interferometer. The absorption of short, low energy laser pulses transmitted through the film and into the tissue generates thermal as well as acoustic transients, which propagate into/the film and modulate its thickness. Th...

  17. 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....

  18. Measuring method for optical fibre sensors

    NARCIS (Netherlands)

    Lammerink, T.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 teste

  19. Fibre optic communications: past, present and future

    Directory of Open Access Journals (Sweden)

    B. M. Lacquet

    2000-07-01

    Full Text Available The exponential increase in the use of the Internet and the consequent growing need for higher bandwidth demand that the telecommu­nications industry expand the laid networks at a much faster rate. Optical fibre is the only transmission medium that has the potential of unlimited bandwidth and the ability to handle very high data rates.

  20. A microring multimode laser using hollow polymer optical fibre

    Indian Academy of Sciences (India)

    M Kailasnath; V P N Nampoori; P Radhakrishnan

    2010-11-01

    We report the observation of multimode laser operation at wavelengths corresponding to whispering-gallery modes from a freestanding microring cavity based on rhodamine B dye-doped PMMA hollow optical fibre. Cylindrical microcavities with diameters 155, 340 and 615 m were fabricated from a dye-doped hollow polymer optical fibre preform. An average mode spacing of 0.17 nm was observed for the 340 m cavity. This shows that the laser mode intensity distribution is concentrated on the outer edge of the cavity.

  1. 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.

  2. 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...

  3. Optical fibre temperature sensor in the cryogenic range

    NARCIS (Netherlands)

    Bertrand, S.; Jalocha, A.; Tribillon, G.; Bouazaoui, M.; Rouhet, J.

    1996-01-01

    The realization of an optical fibre sensor applied to cryogenic temperature measurement in harsh environments is presented. The measurement principle is based on the analysis of the decay-time of the fluorescence emitted by special doped crystals, the excited state lifetimes of which are greatly dep

  4. A microfluidic refractometric sensor based on gratings in optical fibre microwires.

    Science.gov (United States)

    Xu, Fei; Brambilla, Gilberto; Lu, Yanqing

    2009-11-09

    In this paper we investigate a novel method to manufacture gratings in optical fiber microwires and discuss their application to sensing. Gratings can be manufactured by wrapping an optical fiber microwire on a microstructured rod. This method avoids post-processing the thin optical fiber microwire and it has great flexibility: chirping can be realized by designing the air hole size and position in the microstructured rod. By exploiting the large evanescent field in an inner channel, microfluidic refractometric sensors with sensitivity > 10(3) nm/RIU can be achieved.

  5. Chalcogenide microstructured optical fibres for mid-IR applications

    Science.gov (United States)

    Trolès, Johann; Brilland, Laurent

    2017-01-01

    Compared to oxide-based glasses, vitreous materials composed of chalcogen elements (S, Se, Te) show large transparency windows in the infrared. Indeed, chalcogenide glasses can be transparent from the visible up to 12- 18 μm, depending on their compositions. In addition, chalcogenide glasses contain large polarisable atoms and external lone electron pairs that induce exceptional non-linear properties. Consequently, the non-linear properties can be 100 or 1000 times as high as the non-linearity of silica. An original way to obtain single-mode fibres is to design microstructured optical fibres (MOFs). These fibres present unique optical properties thanks to the high degree of freedom in the design of their geometrical structure. Various chalcogenide MOFs operating in the IR range have been elaborated in order to associate the high non-linear properties of these glasses with the original MOF properties. Indeed, chalcogenide MOFs might lead to new devices with unique optical properties in the mid-infrared domain, like multimode or endlessly single-mode transmission of light, small or large mode area fibres, highly birefringent fibres and non-linear properties for wavelength conversion or generation of supercontinuum sources. xml:lang="fr"

  6. Fibre optic sensors for load-displacement measurements and comparisons to piezo sensor based electromechanical admittance signatures

    Science.gov (United States)

    Maheshwari, Muneesh; Annamdas, Venu Gopal Madhav; Pang, John H. L.; Tjin, Swee Chuan; Asundi, Anand

    2015-04-01

    Structural health monitoring techniques using smart materials are on rise to meet the ever ending demand due to increased construction and manufacturing activities worldwide. The civil-structural components such as slabs, beams and columns and aero-components such as wings are constantly subjected to some or the other forms of external loading. This article thus focuses on condition monitoring due to loading/unloading cycle for a simply supported aluminum beam using multiple smart materials. On the specimen, fibre optic polarimetric sensor (FOPS) and fibre Bragg grating (FBG) sensors were glued. Piezoelectric wafer active sensor (PWAS) was also bonded at the centre of the specimen. FOPS and FBG provided the global and local strain measurements respectively whereas, PWAS predicted boundary condition variations by electromechanical admittance signatures. Thus these multiple smart materials together successfully assessed the condition of structure for loading and unloading tests.

  7. Nonlinear microstructured polymer optical fibres

    DEFF Research Database (Denmark)

    Frosz, Michael Henoch

    . The combination of a small core size and zero-dispersion wavelength at the operating wavelength of widely available femtosecond Ti:sapphire lasers led to an extensive research in supercontinuum generation and other nonlinear effects in PCFs. It is crucial for the efficiency of many nonlinear mechanisms...... that the pump laser wavelength is close to the zero-dispersion wavelength and that the core size is small. Recently, work in fabricating PCFs from materials other than silica has intensified. One of the advantages of using alternative materials can be a higher inherent material nonlinearity, which...... to accurately obtain a small core size while maintaining small structural variations during fibre drawing. This talk will give a presentation of how the mPOFs are fabricated and the route to obtaining nonlinear effects in them....

  8. Photoluminescence of an Yb3+/Al3+-codoped microstructured optical fibre

    Institute of Scientific and Technical Information of China (English)

    Xia Chang-Ming; Zhou Gui-Yao; Han Ying; Hou Lan-Tian

    2011-01-01

    An Yb3+/Al3+-codoped microstructured optical fibre is prepared based on photonic crystal fibre technology.The characteristic spectra of preforms and fibres are experimentally investigated.The results show that under a 971 nm excitation,besides the known infrared fluorescence luminescence around 1050 nm,a blue luminescence peak at 486 nm is obtained.Moreover,an unexpected emission peak at 730 nm is also observed.The photoluminescence mechanism of an Yb3+/Al3+-codoped microstructured optical fibre is discussed.The emission peak at 486 nm is attributed to the cooperative upconversion resulting from pairs of Yb3+ions,and the emission peak around 730 nm is ascribed to the stimulated Raman scattering because of nonlinear effects of microstructured optical fibre.The Yb3+/Al3+-codoped microstructured optical fibre is promising for varieties of applications from laser printing and optical recording to cancer treatments,such as photodynamic therapy.

  9. Rare Earth Doped Optical Fibre From Oxide Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Minati Chatterjee; Aharon Gedanken; Renata Reisfeld; Ranjan Sen; Mrinmay Pal; Milan Naskar; Mukul Paul; Shyamal Bhadra; Kamal Dasgupta; Dibyendu Ganguli; Tarun Bandyopadhyay

    2003-01-01

    Rare earth (RE) doped optical fibres were fabricated by using RE oxides coated silica nanoparticles. The fibre properties are comparable to those prepared by conventional techniques. The process offers better control over RE incorporation and homogeneity in the preform.

  10. Fibre-Optic Strain Measurement For Structural Integrity Monitoring

    NARCIS (Netherlands)

    Bruinsma, A.J.A.; Zuylen, P. van; Lamberts, C.W.; Krijger, A.J.T. de

    1984-01-01

    A method is demonstrated for monitoring the structural integrity of large structures, using an optical fibre. The strain distribution along the structure is monitored by measuring the attentuation of light along the length of the fibre.

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

    Science.gov (United States)

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

    2008-12-01

    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.

  12. 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....

  13. Fibre optic sensors for selected wastewater characteristics.

    Science.gov (United States)

    Chong, Su Sin; Aziz, A R Abdul; Harun, Sulaiman W

    2013-07-05

    Demand for online and real-time measurements techniques to meet environmental regulation and treatment compliance are increasing. However the conventional techniques, which involve scheduled sampling and chemical analysis can be expensive and time consuming. Therefore cheaper and faster alternatives to monitor wastewater characteristics are required as alternatives to conventional methods. This paper reviews existing conventional techniques and optical and fibre optic sensors to determine selected wastewater characteristics which are colour, Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD). The review confirms that with appropriate configuration, calibration and fibre features the parameters can be determined with accuracy comparable to conventional method. With more research in this area, the potential for using FOS for online and real-time measurement of more wastewater parameters for various types of industrial effluent are promising.

  14. Fibre Optic Sensors for Selected Wastewater Characteristics

    Directory of Open Access Journals (Sweden)

    Sulaiman W. Harun

    2013-07-01

    Full Text Available Demand for online and real-time measurements techniques to meet environmental regulation and treatment compliance are increasing. However the conventional techniques, which involve scheduled sampling and chemical analysis can be expensive and time consuming. Therefore cheaper and faster alternatives to monitor wastewater characteristics are required as alternatives to conventional methods. This paper reviews existing conventional techniques and optical and fibre optic sensors to determine selected wastewater characteristics which are colour, Chemical Oxygen Demand (COD and Biological Oxygen Demand (BOD. The review confirms that with appropriate configuration, calibration and fibre features the parameters can be determined with accuracy comparable to conventional method. With more research in this area, the potential for using FOS for online and real-time measurement of more wastewater parameters for various types of industrial effluent are promising.

  15. 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.

  16. Optical fibre cable selection for electricity utilities

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    The report provides an assessment of the range of optical fibre cable solutions available, by type e.g. OPGW, ADSS, rather than by design. it also examines the key issues which will influence an electricity utilities decisions and proposes a method of evaluating the options to identify the one which most closely matches the utility's critical needs, with measurements against time, cost and quality targets. (author)

  17. Fibre optic sensor with disturbance localization in one optical fibre

    Science.gov (United States)

    Zyczkowski, M.; Ciurapinski, W.

    2007-05-01

    Ordinary perimeter security systems consist of many individual sensors with detection range 200-300 meters. These limitations are connected with physical phenomena that are used in microwave and infrared barriers as well as in ground and fence cable sensors. On the contrary, fiber optic perimeter sensors can be applied in the range of many kilometers and zone length 200-300 meters is degradation of their possibilities. This paper presents investigation results of a new generation of the fiber optic perimeter sensor in a two Sagnac and Sagna'c interferometers configuration. This system can detect a potential intruder and determine its position along a protected zone. We propose a method that makes use of the inherent properties of both interferometers. After demodulation of signals from both interferometers, obtained amplitude characteristic of the Sagnac interferometer depends on position of a disturbance along the both interferometer. So, quotient of both demodulated characteristics is proportional to the position of the disturbance. Arrangement of a laboratory model of the sensor and its signal processing scheme is presented. During research of a laboratory model, it was possible to detect the position of the disturbance with resolution of about 50m along a 10-km long sensor.

  18. 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...

  19. 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...

  20. Distributed quantum computation via optical fibres

    CERN Document Server

    Serafini, A; Bose, S; Serafini, Alessio; Mancini, Stefano; Bose, Sougato

    2005-01-01

    We investigate the possibility of realising effective quantum gates between two atoms in distant cavities coupled by an optical fibre. We show that highly reliable swap and entangling gates are achievable. We exactly study the stability of these gates in presence of imperfections in coupling strengths and interaction times and prove them to be robust. Moreover, we analyse the effect of spontaneous emission and losses and show that such gates are very promising in view of the high level of coherent control currently achievable in optical cavities.

  1. Development of facilities and methods for the metrological characterization of distributed temperature sensing systems based on optical fibres

    Science.gov (United States)

    Failleau, G.; Beaumont, O.; Delepine-Lesoille, S.; Plumeri, S.; Razouk, R.; Beck, Y. L.; Hénault, J. M.; Bertrand, J.; Hay, B.

    2017-01-01

    Raman distributed temperature sensing (DTS) technologies are currently under evaluation by the nuclear and hydraulic industries as it may bring promising alternatives to classical measurement techniques. The reliability of the DTS measurements, as well as the traceability to the temperature standards, must be ensured throughout the entire period of monitoring (typically over a few tens of years). In order to achieve this goal, one key task consists in the verification of the performances claimed by the DTS devices manufacturers. Thus, the metrological performances and characteristics of the DTS devices, such as their limitations and accuracies, as well as the practical aspects of systems implemented on site should be evaluated step by step. This paper describes the dedicated facilities which have been developed at LNE in order to evaluate and to qualify DTS devices for very demanding applications. A first case study performed on one specific DTS device is detailed. A systematic bias has been observed among others on the spatial resolution. The DTS response to a temperature variation step over 1 m (spatial resolution typically claimed by the manufacturers) of sensing optical fibre corresponds indeed to only 90% of the temperature step magnitude, whereas the full DTS response is obtained in fact for 10 m (the practical spatial resolution) of sensing optical fibre solicited by this temperature step variation.

  2. 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.

  3. A Fibre Optic Sensor Of Physiological Parameters

    Science.gov (United States)

    Legendre, J. P.; Forester, G. V.

    1986-11-01

    This paper presents an ultraminiature fibre optic probe capable of physiological monitoring in situ. The system has been described previously where a fibre optic reflectometer was configured as a temperature sensor and as a refractometer. For the present experiments a bare fibre tip was used as sensing element. We show that we have been able to monitor cyclic physiological parameters such as heart and respiratory rates in various animal preparations. The probe has been used to obtain signals from the oesophagus, the lower gastro-intestinal tract, the abdominal cavity and from blood vessels (arteries and veins). The probe has also measured phasic activity coincident with mechanical activity of isolated heart muscle. The small physical size of the sensor (125 µm diameter), its flexibility and the fact that it is biologically inert are all very important characteristics for medical and biological considerations. Most recently, the probe has been used to monitor cardiac and respiratory rates while obtaining NMR spectra assessing metabolic activity. This was possible only because the probe is magnetically transparent.

  4. A fibre optic dosimeter customised for brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Suchowerska, N. [Department of Radiation Oncology, Royal Prince Alfred Hospital, Camperdown, NSW 2050 (Australia); School of Physics, University of Sydney, NSW 2006 (Australia)], E-mail: Natalka@email.cs.nsw.gov.au; Lambert, J.; Nakano, T. [Department of Radiation Oncology, Royal Prince Alfred Hospital, Camperdown, NSW 2050 (Australia); School of Physics, University of Sydney, NSW 2006 (Australia); Law, S. [School of Physics, University of Sydney, NSW 2006 (Australia); Optical Fibre Technology Centre, University of Sydney, 206 National Innovation Centre, Australian Technology Park, Eveleigh, NSW 1430 (Australia); Elsey, J. [Bandwidth Foundry Pty Ltd, Australian Technology Park, NSW, 1430 (Australia); McKenzie, D.R. [School of Physics, University of Sydney, NSW 2006 (Australia)

    2007-04-15

    In-vivo dosimetry for brachytherapy cancer treatment requires a small dosimeter with a real time readout capability that can be inserted into the patient to determine the dose to critical organs. Fibre optic scintillation dosimeters, consisting of a plastic scintillator coupled to an optical fibre, are a promising dosimeter for this application. We have implemented specific design features to optimise the performance of the dosimeter for specific in-vivo dosimetry during brachytherapy. Two sizes of the BrachyFOD{sup TM} scintillation dosimeter have been developed, with external diameters of approximately 2 and 1 mm. We have determined their important dosimetric characteristics (depth dose relation, angular dependence, energy dependence). We have shown that the background signal created by Cerenkov and fibre fluorescence does not significantly affect the performance in most clinical geometries. The dosimeter design enables readout at less than 0.5 s intervals. The clinical demands of real time in-vivo brachytherapy dosimetry can uniquely be satisfied by the BrachyFOD{sup TM}.

  5. 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...

  6. Fibre Optic Biosensor Assay of Newcastle Disease Virus

    Science.gov (United States)

    1993-10-01

    A fluorometric sandwich immunoassay for Newcastle disease virus (NDV) was developed using a fibre optic biosensor. Antibodies directed against NDV...and low baseline variation. These and other properties of the fibre optic biosensor indicate that it has the potential to serve as an on-line...continuous monitoring device of an automated or semiautomated detection system. As a part of the fibre optic biosensor development, the surface coverage of

  7. A Prototype Fibre Optic Gyroscope for Missile Guidance Applications,

    Science.gov (United States)

    This paper describes the design of a prototype fibre optic gyro, which is intended for missile guidance applications. Important design constraints...beam-splitter. Serrodyne phase ramps are impressed on the light propagating round the fibre optic sensor coil connected to the integrated optics chip

  8. Simultaneous transfer of optical frequency and time over 306 km long-haul optical fibre link

    Science.gov (United States)

    Hucl, Vaclav; Cizek, Martin; Pravdova, Lenka; Rerucha, Simon; Hrabina, Jan; Mikel, Bretislav; Smotlacha, Vladimir; Vojtech, Josef; Lazar, Josef; Cip, Ondrej

    2016-12-01

    Optical fibre links for distributing optical frequencies and time stamps were researched and experimentally tested in the past fifteen years. They have been used mainly for stability comparison of experimental optical clocks. But recent development puts demands on a technology transfer from laboratory experiments to the real industry. The remote calibration of interrogators of Fibre Bragg Grating strain sensory networks is one of important examples. The first step of the adoption the time and frequency broadcasting should be the drop-out free long-term operation of this technology between research laboratories connected via long-haul fibre links. We present a 306 km long-haul optical fibre link between the cities of Prague and Brno in the Czech Republic where a coherent transfer of stable optical frequency and a stable time signal has been firstly demonstrated. The link between ISI CAS Brno and CESNET Prague uses an internet communication fibre where a window of 1540-1546 nm is dedicated for the coherent transfer and 1PPS signal. The link is equipped with 6 bidirectional EDFA amplifiers. The optical frequency standard based on the highly-coherent laser Koheras Adjustik working at 1540.5 nm and stabilized with a saturation absorption spectroscopy technique was used for the coherent wave transfer. The suppression of the Doppler shift induced by the optical fibre was based on an accoustooptical modulator with a servo-loop including a fast PID controller processing the beat-note frequency given by mixing of the Adjustik laser (Brno) and the reflected frequency of this laser from the far end of 306 km long-haul fibre link (Prague). We verified the Doppler shift suppression for the coherent wave with a measuring method analysing the transport delay of the 1PPS signal.

  9. 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...

  10. Phenomena of optic-bound effect on fibre optic gyro

    Institute of Scientific and Technical Information of China (English)

    Song Ning-Fang; Zhang Chun-Xi; Jin Jing

    2007-01-01

    The optic-bound effect on fibre optic gyro (FOG) precision is analysed theoretically,and formulas describing the change of FOG light power under the action of optic-bound effect axe given.It is confirmed that optic-bound effect is a main instantaneous non-reciprocity effect of FOG in addition to the Sagnac effect and can lead to a dynamic error of FOG in practical environments.An approach to suppressing or eliminating the error due to the optic-bound effect is presented and verified experimentally.The result shows that the approach is valid and the precision of FOG is improved observably.

  11. Real-time fibre optic radiation dosimeters for nuclear environment monitoring around thermonuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, A. Fernandez; Brichard, B. [SCK .CEN, Belgian Nuclear Research Centre, Boeretang 200, B-2400 Mol (Belgium); O' Keeffe, S.; Fitzpatrick, C.; Lewis, E. [Electronic and Computer Engineering Department, University of Limerick, Limerick (Ireland); Vaille, J.-R.; Dusseau, L. [CEM2-Universite Montpellier II, cc083 place E. Bataillon, 34095 Montpellier Cedex 05 (France); Jackson, D.A. [School of Physical Sciences, University of Kent, Kent CT2 7NR (United Kingdom); Ravotti, F.; Glaser, M. [European Organization for Nuclear Research CERN, TS-LEA-RAD/PH-DT2-SD, CH-1211 Geneva 23 (Switzerland); El-Rabii, H. [Laboratoire de Combustion et de Detonique, ENSMA/CNRS, 1 av. Clement Ader, 86961 Chasseneuil-Futuroscope (France)], E-mail: afernand@sckcen.be

    2008-01-15

    The ability of fibre optic sensors to operate in hazardous nuclear environments and their intrinsic immunity to electro-magnetic interference make fibre optic sensing a very promising technology for the future ITER thermonuclear fusion reactor. In this paper, we evaluate fibre optic sensing technology for monitoring radiation dose in the vicinity of ITER during its operation and during the maintenance periods. First, the performance of an OSL dosimeter interrogated remotely using radiation tolerant optical fibres is evaluated both for real-time and integrating measurements for doses exceeding 100 Gy. We demonstrate its satisfactory operation in a mixed gamma neutron field. Second, we discuss the successful calibration of a new scintillating fibre optic radiation probe based on CsI(TI) crystals for operation in the dose-rate range 0.3-3000 mGy/h. The CsI(TI) crystal scintillator is mounted at the end of a 10-m long multimode fibre transceiver link to allow for remote deployment. The probes can detect and measure gamma dose rates ranging from 1 to 1000 mGy/h. Finally, we investigate the possible use of commercially available PMMA plastic optical fibres as on-line dosimeters up to 34 kGy. The dose measurement is derived from the radiation-induced attenuation in the optical fibre itself. A novel interrogation scheme based on a ratiometric technique is proposed for real-time dosimetry.

  12. Fibre optic system for biochemical and microbiological sensing

    Energy Technology Data Exchange (ETDEWEB)

    Penwill, L A; Slater, J H; Hayes, N W; Tremlett, C J [Evanes Co Ltd, 4 and 5 Forde Court, Newton Abbot, Devon, TQ12 4AD (United Kingdom)

    2007-07-15

    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.

  13. Rare Earth Doped Silica Optical Fibre Sensors for Dosimetry in Medical and Technical Applications

    Directory of Open Access Journals (Sweden)

    N. Chiodini

    2014-01-01

    Full Text Available Radioluminescence optical fibre sensors are gaining importance since these devices are promising in several applications like high energy physics, particle tracking, real-time monitoring of radiation beams, and radioactive waste. Silica optical fibres play an important role thanks to their high radiation hardness. Moreover, rare earths may be incorporated to optimise the scintillation properties (emission spectrum, decay time according to the particular application. This makes doped silica optical fibres a very versatile tool for the detection of ionizing radiation in many contexts. Among the fields of application of optical fibre sensors, radiation therapy represents a driving force for the research and development of new devices. In this review the recent progresses in the development of rare earth doped silica fibres for dosimetry in the medical field are described. After a general description of advantages and challenges for the use of optical fibre based dosimeter during radiation therapy treatment and diagnostic irradiations, the features of the incorporation of rare earths in the silica matrix in order to prepare radioluminescent optical fibre sensors are presented and discussed. In the last part of this paper, recent results obtained by using cerium, europium, and ytterbium doped silica optical fibres in radiation therapy applications are reviewed.

  14. Large-mode-area leaky optical fibre fabricated by MCVD

    OpenAIRE

    Dussardier, Bernard; Trzesien, Stanislaw; Ude, Michèle; Rastogi, Vipul; Kumar, Ajeet; Monnom, Gérard

    2008-01-01

    International audience; A large mode area single-mode optical fibre based on leaky mode filtering was prepared by MCVD. The cladding structure discriminates the fundamental mode from the higher order ones. A preliminary version has 25-µm core diameter and 0.11 numerical aperture. A Gaussian-like mode with 22-µm MFD is observed after 3-m propagation, in agreement with modeling.

  15. 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....... The fabricated SIPOF has a core made from TOPAS with a glass transition temperature of 134 degrees C and a cladding from ZEONEX with a glass transition temperature of 138 degrees C. The main advantages of the proposed SIPOF are the low water absorption and good chemical resistance compared to the conventional...

  16. Optical nanofibre integrated into an optical tweezers for particle manipulation, in situ fibre probing, and optical binding studies

    CERN Document Server

    Gusachenko, Ivan; Frawley, Mary C; Chormaic, Síle Nic

    2015-01-01

    Precise control of particle positioning is desirable in many optical propulsion and sorting applications. Here, we develop an integrated platform for particle manipulation consisting of a combined optical nanofibre and optical tweezers system. Individual silica microspheres were introduced to the nanofibre at arbitrary points using the optical tweezers, thereby producing pronounced dips in the fibre transmission. We show that such consistent and reversible transmission modulations depend on both particle and fibre diameter, and can be used as a reference point for in situ nanofibre or particle size measurement. Thence, we combine scanning electron microscope (SEM) size measurements with nanofibre transmission data to provide calibration for particle-based fibre assessment. This integrated optical platform provides a method for selective evanescent field manipulation of micron-sized particles and facilitates studies of optical binding and light-particle interaction dynamics.

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

    Indian Academy of Sciences (India)

    C L Linslal; Jaison Peter; S Mathew; M Kailasnath

    2014-02-01

    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 polymer preform. A blueshift in the mode structure was observed with decrease in fibre diameter leading to wide range tunability of the laser emission.

  18. Fluorescent optical fibre chemosensor for the detection of mercury

    Science.gov (United States)

    Nguyen, T. Hien; Wren, Stephen P.; Sun, Tong; Grattan, Kenneth T. V.

    2016-11-01

    This work aims to develop a stable, compact and portable fibre optic sensing system which is capable of real time detection of the mercury ion (II), Hg2+. A novel fluorescent polymeric material for Hg2+ detection, based on a coumarin derivative (acting as the fluorophore) and an azathia crown ether moiety (acting as the mercury ion receptor), has been designed and synthesized. The material was covalently attached to the distal end of an optical fibre and exhibited a significant increase in fluorescence intensity in response to Hg2+ in the μM concentration range via a photoinduced electron transfer (PET) mechanism. The sensor has also demonstrated a high selectivity for Hg2+ over other metal ions. A washing protocol was identified for sensor regeneration, allowing the probe to be re-used. The approach developed in this work can also be used for the preparation of sensors for other heavy metals.

  19. Elimination of Cerenkov interference in a fibre-optic-coupled radiation dosemeter.

    Science.gov (United States)

    Justus, Brian L; Falkenstein, Paul; Huston, Alan L; Plazas, Maria C; Ning, Holly; Miller, Robert W

    2006-01-01

    An optical fibre point dosemeter based on the gated detection of the luminescence from a Cu(1+)-doped fused quartz detector effectively eliminated errors due to Cerenkov radiation and native fibre fluorescence. The gated optical fibre dosemeter overcomes serious problems faced by scintillation and optically stimulated luminescence approaches to optical fibre point dosimetry. The dosemeter was tested using an external beam radiotherapy machine that provided pulses of 6 MV X rays. Gated detection was used to discriminate the signal collected during the radiation pulses, which included contributions from Cerenkov radiation and native fibre fluorescence, from the signal collected between the radiation pulses, which contained only the long-lived luminescence from the Cu(1+)-doped fused quartz detector. Gated detection of the luminescence provided accurate, real-time dose measurements that were linear with absorbed dose, independent of dose rate and that were accurate for all field sizes studied.

  20. Corrosion induced strain monitoring through fibre optic sensors

    Energy Technology Data Exchange (ETDEWEB)

    Grattan, S K T [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast, David Keir Building, Belfast, BT9 5AG (United Kingdom); Basheer, P A M [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast, David Keir Building, Belfast, BT9 5AG (United Kingdom); Taylor, S E [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast, David Keir Building, Belfast, BT9 5AG (United Kingdom); Zhao, W [School of Engineering and Mathematical Sciences, City University, Northampton Square, London, EC1V 0HB (United Kingdom); Sun, T [School of Engineering and Mathematical Sciences, City University, Northampton Square, London, EC1V 0HB (United Kingdom); Grattan, K T V [School of Engineering and Mathematical Sciences, City University, Northampton Square, London, EC1V 0HB (United Kingdom)

    2007-10-15

    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.

  1. Distributed acoustic fibre optic sensors for condition monitoring of pipelines

    Science.gov (United States)

    Hussels, Maria-Teresa; Chruscicki, Sebastian; Habib, Abdelkarim; Krebber, Katerina

    2016-05-01

    Industrial piping systems are particularly relevant to public safety and the continuous availability of infrastructure. However, condition monitoring systems based on many discrete sensors are generally not well-suited for widespread piping systems due to considerable installation effort, while use of distributed fibre-optic sensors would reduce this effort to a minimum. Specifically distributed acoustic sensing (DAS) is employed for detection of third-party threats and leaks in oil and gas pipelines in recent years and can in principle also be applied to industrial plants. Further possible detection routes amenable by DAS that could identify damage prior to emission of medium are subject of a current project at BAM, which aims at qualifying distributed fibre optic methods such as DAS as a means for spatially continuous monitoring of industrial piping systems. Here, first tests on a short pipe are presented, where optical fibres were applied directly to the surface. An artificial signal was used to define suitable parameters of the measurement system and compare different ways of applying the sensor.

  2. Fibre optic pressure sensor using a microstructured POF

    Science.gov (United States)

    Arrizabalaga, Oskar; Durana, Gaizka; Aldabaldetreku, Gotzon; Zubia, Joseba

    2015-05-01

    Based on the attractive elasto-optic properties of single-mode microstructured polymer optical fibres (SM mPOFs) reported elsewhere,10 mode polarisation may be used as sensing probe for several parameters of interest like mechanical pressure. We report on a simplified detection scheme that does not require measuring the actual polarisation state of the light emerging from the mPOF. A polariser and a photodetector in a proper configuration are only required. The detected light intensity shows a high linearity with applied force to the mPOF.

  3. Semiconductor optical fibres for infrared applications: A review

    Science.gov (United States)

    Peacock, Anna C.; Healy, Noel

    2016-10-01

    Over the last decade a new class of optical fibre has emerged that incorporates semiconductor materials within the core. These fibres are rich in optoelectronic functionality and offer extended transmission bands across the infrared spectral region so that their application potential is vast. Various fabrication methods have been developed to produce fibres with a range of unary and compound semiconductor core materials, which can be either amorphous or crystalline in form. This review discusses the main fabrication procedures and the infrared optical properties of the semiconductor fibres that have been fabricated to date, then takes a look at the future prospects of this exciting new technology.

  4. Microstructured polymer optical fibre sensors for opto-acoustic endoscopy

    Science.gov (United States)

    Broadway, Christian; Gallego, Daniel; Pospori, Andreas; Zubel, Michal; Webb, David J.; Sugden, Kate; Carpintero, Guillermo; Lamela, Horacio

    2016-04-01

    Opto-acoustic imaging is a growing field of research in recent years, providing functional imaging of physiological biomarkers, such as the oxygenation of haemoglobin. Piezo electric transducers are the industry standard detector for ultrasonics, but their limited bandwidth, susceptibility to electromagnetic interference and their inversely proportional sensitivity to size all affect the detector performance. Sensors based on polymer optical fibres (POF) are immune to electromagnetic interference, have lower acoustic impedance and a reduced Young's Modulus compared to silica fibres. Furthermore, POF enables the possibility of a wideband sensor and a size appropriate to endoscopy. Micro-structured POF (mPOF) used in an interferometric detector has been shown to be an order of magnitude more sensitive than silica fibre at 1 MHz and 3 times more sensitive at 10 MHz. We present the first opto-acoustic measurements obtained using a 4.7mm PMMA mPOF Bragg grating with a fibre diameter of 130 μm and present the lateral directivity pattern of a PMMA mPOF FBG ultrasound sensor over a frequency range of 1-50 MHz. We discuss the impact of the pattern with respect to the targeted application and draw conclusions on how to mitigate the problems encountered.

  5. Femtosecond fibre laser stabilisation to an optical frequency standard using a KTP electro-optic crystal

    Energy Technology Data Exchange (ETDEWEB)

    Nyushkov, B N [Novosibirsk State University, Novosibirsk (Russian Federation); Pivtsov, V S; Koliada, N A [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation); Kaplun, A B; Meshalkin, A B [S.S. Kutateladze Institute of Heat Physics, Siberian Division of the Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2015-05-31

    A miniature intracavity KTP-based electro-optic phase modulator has been developed which can be used for effective stabilisation of an optical frequency comb of a femtosecond erbiumdoped fibre laser to an optical frequency standard. The use of such an electro-optic modulator (EOM) has made it possible to extend the working frequency band of a phase-locked loop system for laser stabilisation to several hundred kilohertz. We demonstrate that the KTP-based EOM is sufficiently sensitive even at a small optical length, which allows it to be readily integrated into cavities of femtosecond fibre lasers with high mode frequency spacings (over 100 MHz). (extreme light fields and their applications)

  6. Headspace single-drop microextraction and fibre optics-based cuvetteless micro-spectrophotometry for the determination of chloride involving oxidation with permanganate.

    Science.gov (United States)

    Pillai, Aradhana K K V; Jain, Archana; Verma, Krishna K

    2010-03-15

    Headspace single-drop microextraction has been investigated for the determination of chloride in conjunction with fibre optic-based cuvetteless micro-spectrophotometry which accommodates sample volume of 1 microL placed between the two ends of optical fibres. Method has been evolved for the determination of 0.025-4 mg L(-1) of chloride involving its oxidation with permanganate in sulphuric acid medium, and reaction of chlorine with 2 microL drop of starch-iodide reagent suspended at the tip of microsyringe needle in the headspace of the reaction mixture. The limit of detection was found to be 2.8 microg L(-1) of chloride which was better than obtained by existing methods. The method was highly selective and a number of ions which interfered severely in other methods did not affect the results. The method has been used to analyze water samples, inorganic compounds and cement when the overall recovery of chloride was 94.9% with a relative standard deviation of 3.9%.

  7. Flat Ge-doped optical fibres for food irradiation dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Noor, N. Mohd; Jusoh, M. A. [Department of Imaging, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Razis, A. F. Abdull [Food Safety Research Centre, Faculty of Food Science and Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Laboratory of UPM-MAKNA Cancer Research, Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Alawiah, A. [Faculty of Engineering and Technology, Multimedia University, 75450 Malacca (Malaysia); Bradley, D. A. [Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2015-04-24

    Exposing food to radiation can improve hygiene quality, germination control, retard sprouting, and enhance physical attributes of the food product. To provide for food safety, radiation dosimetry in irradiated food is required. Herein, fabricated germanium doped (Ge-doped) optical fibres have been used. The fibres have been irradiated using a gamma source irradiator, doses in the range 1 kGy to 10 kGy being delivered. Using Ge-doped optical fibres of variable size, type and dopant concentration, study has been made of linearity, reproducibility, and fading. The thermoluminescence (TL) yield of the fibres were obtained and compared. The fibres exhibit a linear dose response over the investigated range of doses, with mean reproducibility to within 2.69 % to 8.77 %, exceeding the dose range of all commercial dosimeters used in evaluating high doses for the food irradiation industry. TL fading of the Ge-doped flat fibres has been found to be < 13%.

  8. Signal Processing for Fibre-optic Distributed Sensing Techniques Employing Brillouin Scattering

    Institute of Scientific and Technical Information of China (English)

    XIAO Shang-hui; LI Li

    2009-01-01

    As fibre optic distributed scattering sensing systems are providing innovative solutions for the monitoring of large structures, Brillouin-based distributed scattering sensing techniques represent a new physical approach for structures health monitoring, which seems extremely promising and is receiving most attentions. This paper comprehensively presents some methods of signal interrogation for fibre optic Brillouin-based distributed scattering sensing technology, especially establishes an accurate Pseudo-Voigt model of Brillouin gain spectrum and gives some results on spectrum analysis and data processing.

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

    DEFF Research Database (Denmark)

    Bundalo, Ivan-Lazar

    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 optical fibre core which act as a wavelength specific reflector. The fibres used are made of Polymethyl methacrylate......, strain duration, increasing number of cycles, and it decreases with relaxation duration. For strains up to 0.9%, fast relaxing ΔΛfast range takes no less than 65% of the total strain range. Increase in ΔΛslow due to cyclic straining and relaxing seems to reach an equilibrium value, suggesting that ΔΛslow...... 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...

  10. Infrared Supercontinuum Generation in Optical Fibres

    DEFF Research Database (Denmark)

    Dupont, Sune Vestergaard Lund

    evolution has been investigated and also the mechanisms governing the pulse broadening. The generated infrared light has some crucial advantages compared to normal visible light. Infrared light can especially be used for spectroscopy, where the specific molecular absorptions are probed directly. This we...... 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...... have used for infrared microscopy where substance recognition is obtained in addition to magnification. Choosing a specific wavelength images showing only one substance can consequently be generated. More simple light sources are already used in such infrared microscopes to investigate tissue assays...

  11. Optimal Extraction of Fibre Optic Spectroscopy

    CERN Document Server

    Sharp, R

    2009-01-01

    We report an optimal extraction methodology, for the reduction of multi-object fibre spectroscopy data, operating in the regime of tightly packed (and hence significantly overlapping) fibre profiles. The routine minimises crosstalk between adjacent fibres and statistically weights the extraction to reduce noise. As an example of the process we use simulations of the numerous modes of operation of the AAOmega fibre spectrograph and observational data from the SPIRAL Integral Field Unit at the Anglo-Australian Telescope.

  12. A Model of Magneto-mechano-optical Transfer in Fibre-optic Magnetic Sensors with Magnetostrictive Films

    Institute of Scientific and Technical Information of China (English)

    LIU Ji-yan; SI Yong-min

    2004-01-01

    Fibre-optic magnetic sensors with magnetostrictive films are used as all-fibre Mach-Zehnder interferometer to detect the optical phase shift, which is caused by the magnetostriction-induced strains transferred from the msgnetostrictive film to the fibre. A theoretical model based on the plane strain approximation and uniform axial strain is developed to determine the magneto-mechano-optical transfer relations in this kind of sensors. The expression for the model is presented as well as relation of the phase shift in the fibre to the magnetic and elastic properties of the magnetostrictive film coated on the fibre. And from the model, the thickness of the film has significant influence on the phase shift.

  13. OPTICAL FIBRES: Photoinduced and thermal reactions involving hydrogen in high-germania-core optical fibres

    Science.gov (United States)

    Rybaltovskii, A. O.; Koltashev, V. V.; Medvedkov, O. I.; Rybaltovsky, A. A.; Sokolov, V. O.; Klyamkin, Semen N.; Plotnichenko, V. G.; Dianov, Evgenii M.

    2008-12-01

    We report a Raman scattering study of photoinduced and thermal reactions between H2 and germanosilicate optical fibres with 22 mol % and 97 mol % GeO2 in the core (F1 and F2, respectively) after H2 loading at 150 MPa (1500 atm). The mechanisms of photoreactions are investigated in a wide range of incident laser wavelengths (244, 333, 354, 361 and 514 nm). Thermal reactions are studied at 500 °C. The results indicate that the main mechanism behind the formation of hydrogen-containing defects with Raman bands at 700, 750, 2190, 3600 and 3680 cm-1 involves ≡Ge—O—Ge≡ or ≡Ge—O—Si≡ bond breaking and formation of hydride and hydroxyl species: =GeH2 (700, 750 cm-1), ≡Ge—H (2190 cm-1), ≡GeO—H (3600 cm-1) and ≡SiO—H (3680 cm-1). The key features of the reactions in the F1 and F2 fibres are analysed. In particular, photoinduced reactions give ≡Si—OH groups only in the F1 fibres, whereas the formation of germanium nanoclusters at a relatively low temperature (~500 °C) or ≡GeO—H and ≡Ge—H defects under 514-nm irradiation has only been observed in the F2 fibres.

  14. Multiplexed fibre optic sensors for monitoring resin infusion, flow, and cure in composite material processing

    Science.gov (United States)

    Chehura, Edmon; Jarzebinska, Renata; Da Costa, Elisabete F. R.; Skordos, Alexandros A.; James, Stephen W.; Partridge, Ivana K.; Tatam, Ralph P.

    2013-04-01

    The infusion, flow and cure of RTM6 resin in a carbon fibre reinforced composite preform have been monitored using a variety of multiplexed fibre optic sensors. Optical fibre Fresnel sensors and tilted fibre Bragg grating (TFBG) sensors were configured to monitor resin infusion/flow in-plane of the component. The results obtained from the different sensors were in good agreement with visual observations. The degree of cure was monitored by Fresnel sensors via a measurement of the refractive index of the resin which was converted to degree of cure using a calibration determined from Differential Scanning Calorimetry. Fibre Bragg grating sensors fabricated in highly linearly birefringent fibre were used to monitor the development of transverse strain during the cure process, revealing through-thickness material shrinkage of about 712 μɛ and residual strain of 223 μɛ. An alternative approach to infusion monitoring, based on an array of multiplexed tapered optical fibre sensors interrogated using optical frequency domain reflectometry, was also investigated in a separate carbon fibre preform that was infused with RTM6 resin.

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

    Institute of Scientific and Technical Information of China (English)

    LIU Peng; YAN Feng-Ping; LI Jian; WANG Lin; NING Ti-Gang; GONG Tao-Rong; JIAN Shui-Sheng

    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 lO0%-refiective mirror.A strain-induced uniform fibre Bragger grating (FBG) which functions as a partial-refiecting 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 7.0Ohm 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 50km transmission experiment was performed using our TEDFL at a 10 Gb/s modulation rate.

  16. 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

  17. Relativistic Corrections for Time and Frequency Transfer in Optical Fibres

    CERN Document Server

    Geršl, J; Wolf, P

    2016-01-01

    We derive relativistic corrections for one-way and two-way time and frequency transfer over optical fibres neglecting no terms that exceed 1 ps in time and $10^{-18}$ in fractional frequency, and estimate their magnitude in typical fibre links. We also provide estimates of the uncertainties in the evaluation of the relativistic corrections due to imperfect knowledge of parameters like the coordinates of the fibre and stations, Earth rotation, or thermal effects of the fibre index and length. The links between Teddington(UK) and Paris(F) as well as Braunschweig(D) and Paris(F), that are currently under construction, are studied as specific examples.

  18. 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.

  19. A proposed fibre optic time domain optical coherence tomography system using a micro-photonic stationary optical delay line

    Science.gov (United States)

    Jansz, Paul Vernon; Wild, Graham; Hinckley, Steven

    2008-04-01

    Conventional time domain Optical Coherence Tomography (OCT) relies on a reference Optical Delay Line (ODL). These reference ODLs require the physical movement of a mirror to scan a given depth range. This movement results in instrument degradation. We propose a new optical fibre based time domain OCT system that makes use of a micro-photonic structure as a stationary ODL. The proposed system uses an in-fibre interferometer, either a Michelson or a Mach-Zhender. The reference ODL makes use of a collimator to expand the light from the optical fibre. This is them expanded in one dimension via planar optics, that is, a cylindrical lens based telescope, using a concave and convex lens. The expanded beam is them passed through a transmissive Spatial Light Modulator (SLM), specifically a liquid crystal light valve used as an optical switch. Light is then reflected back through the system off the micro-photonic structure. The micro-photonic structure is a one dimensional array of stagged mirror steps, called a Stepped Mirror Structure (SMS). The system enables the selection of discrete optical delay lengths. The proposed ODL is capable of depth hoping and multicasting. We discuss the fabrication of the SMS, which consists of eight steps, each approximately 150 μm high. A change in notch frequency using an in-fibre Mach Zhender interferometer was used to gauge the average step height. The results gave an average step height of 146 μm.

  20. 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.

  1. Measurement of Rotating Blade Tip Clearance with Fibre-Optic Probe

    Energy Technology Data Exchange (ETDEWEB)

    Cao, S Z; Duan, F J; Zhang, Y G [State Key Laboratory of Measurement Technology and Instruments, Tianjin, University. Tianjin, 300072 (China)

    2006-10-15

    This paper described a tip clearance measuring system with fibre-optic probe. The system is based on a novel tip clearance sensor of optical fibre-bundle mounted on the casing, rotating speed synchronization sensor mounted on the rotating shaft, the tip clearance preamplification processing circuit followed by high speed data-acquisition unit. A novel tip clearance sensor of trifurcated optical fibre bundle was proposed and demonstrated. It is independent of material of measured surface but capacitive probe demands target conductive. Measurements can be taken under severe conditions such as ionization. Sensor circuitry and data acquisition circuit were successfully designed. With the help of Rotation synchronized sensor, all the blades can be detected in real-time. Because of fibre-optic sensor, the measuring system has commendably frequency response, which can work well in high rotating speed from 0-15000rpm.The measurement range of tip clearance is 0-3mm with 25um precision.

  2. 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.

  3. Development and evaluation of an optical fibre-based helium–neon laser irradiation system for tissue regeneration: A pilot study

    Indian Academy of Sciences (India)

    Vijendra Prabhu; B S Satish Rao; B Nageshwara Rao; B Kiran Aithal; B Satish Shenoy; K K Mahato

    2010-12-01

    Low level laser therapy is being extensively used to treat various medical ailments including wound healing. In the present study, an optical fibre-based helium–neon (He–Ne) laser irradiation system was designed, developed and evaluated for optimum tissue repair on mice excision wounds. Circular wounds of 15 mm diameter were created on the dorsum of animals and single exposure of uniformly distributed laser beam was administered at 1, 2 and 3 J/cm2 to the respective test groups with suitable controls. Progression of healing was monitored by measuring wound contraction and mean healing time. Significant reduction in wound size and mean healing time ( < 0.001) were observed in the test groups for the laser dose of 2 J/cm2 compared to the unilluminated controls, suggesting the suitability of this dose.

  4. 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

  5. Micro fibre optic flow checker for the medical analysis application.

    Science.gov (United States)

    Wang, Danping

    2007-01-01

    Two micro fibre optic flow checkers are presented in this paper. They are used for a medical analysis to control a solvent flow up to 1microl/min resolution. A fibre optic sensor as well as a hydraulic system are the principle components of these flow checkers. This paper describes the principle and the experiment setup. It gives the linearity, the repeatability and the stability results.

  6. Optical fibre luminescence sensor for real-time LDR brachytherapy dosimetry

    Science.gov (United States)

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

    2016-05-01

    An optical fibre sensor for monitoring low dose radiation is presented. The sensor is based on a scintillation material embedded within the optical fibre core, which emits visible light when exposed to low level ionising radiation. The incident level of ionising radiation can be determined by analysing the optical emission. An optical fibre sensor is presented, based on radioluminescence whereby radiation sensitive scintillation material, terbium doped gadolinium oxysulphide (Gd2O2S:Tb), is embedded in a cavity of 250μm of a 500μm plastic optical fibre. The sensor is designed for in-vivo monitoring of the radiation dose during radio-active seed implantation for brachytherapy, in prostate cancer treatment, providing oncologists with real-time information of the radiation dose to the target area and/or nearby critical structures. The radiation from the brachytherapy seeds causes emission of visible light from the scintillation material through the process of radioluminescence, which penetrates the fibre, propagating along the optical fibre for remote detection using a multi-pixel photon counter. The sensor demonstrates a high sensitivity to Iodine-125, the radioactive source most commonly used in brachytherapy for treating prostate cancer.

  7. Investigation of the limits of a fibre optic sensor system for measurement of temperature distribution

    DEFF Research Database (Denmark)

    Brehm, Robert; Johnson, Frank

    2006-01-01

    The aim of this project is to develop an innovative temperature sensor system which is able to measure the temperature distribution along a fibre optical cable. This technique for temperature measurement is based on Optical Time Domain Reflectometry (OTDR). ©2006 IEEE.......The aim of this project is to develop an innovative temperature sensor system which is able to measure the temperature distribution along a fibre optical cable. This technique for temperature measurement is based on Optical Time Domain Reflectometry (OTDR). ©2006 IEEE....

  8. Deep ultraviolet laser micromachining of novel fibre optic devices

    Science.gov (United States)

    Li, J.; Dou, J.; Herman, P. R.; Fricke-Begemann, T.; Ihlemann, J.; Marowsky, G.

    2007-04-01

    A deep ultraviolet F2 laser, with output at 157-nm wavelength, has been adopted for micro-shaping the end facets of single and multi-mode silica optical fibres. The high energy 7.9-eV photons drive strong interactions in the wide-bandgap silica fibres to enable the fabrication of surface-relief microstructures with high spatial resolution and smooth surface morphology. Diffraction gratings, focusing lenses, and Mach-Zehnder interferometric structures have been micromachined onto the cleaved-fibre facets and optically characterized. F2-laser micromachining is shown to be a rapid and facile means for direct-writing of novel infibre photonic components.

  9. Analysis of Photosensitivity of Copolymer Optical Fibre Preform

    Institute of Scientific and Technical Information of China (English)

    MA Hui; LI Zeng-Chang; MING Hai; ZHANG Qi-Jin; TAM Hwa-Yaw; ZHANG Yong-Sheng; ZHANG Tao; WANG Pei; XIE Jian-Ping

    2004-01-01

    @@ The photosensitivity of copolymer optical fibre preform is analysed in comparison with the doped one. The effects of write conditions such as pump power and pump time have been studied. Then, the preform is drawn into single mode polymer optical fibre with core refractive index of 1.499, and core-cladding refractive-index difference of 0.008. Long-period birefringence gratings with period of 120um are fabricated in the fibre. The duty cycle is 50%, and the refractive index change in the exposed area is about 1 × 10-3.

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

    Institute of Scientific and Technical Information of China (English)

    XIAO Li; ZHANG Wei; HUANG Yi-Dong; PENG Jiang-De; ZHAO Hong; YANG Ke-Wu

    2008-01-01

    Nonfinearity 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.

  11. 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.

  12. Optical fibre biosensors using enzymatic transducers to monitor glucose

    Science.gov (United States)

    Scully, P. J.; Betancor, L.; Bolyo, J.; Dzyadevych, S.; Guisan, J. M.; Fernández-Lafuente, R.; Jaffrezic-Renault, N.; Kuncová, G.; Matejec, V.; O'Kennedy, B.; Podrazky, O.; Rose, K.; Sasek, L.; Young, J. S.

    2007-10-01

    The construction and performance of a novel enzyme based optical sensor for in situ continuous monitoring of glucose in biotechnological production processes is presented. Sensitive optical coatings are formed from inorganic-organic hybrid polymers (ORMOCER®sORMOCER®: Trademark of Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e. V. in Germany.) combined with a flurophore (ruthenium complex) and an enzyme, and applied to lenses, declad polymer optical fibre (POF) and polymer clad silica fibre (PCS). The enzyme, glucose oxidase, catalyzes oxidization of glucose to gluconic acid by depleting oxygen. Oxygen consumption is determined by measuring the fluorescence lifetime of metal organic ruthenium complexes which are quenched by oxygen. The coatings developed were designed to adhere to glass and polymer surfaces, to be compatible with enzymes and ruthenium complexes, and were demonstrated both as double- and single-layer structures. The sensor response to gaseous oxygen, dissolved oxygen and dissolved glucose was measured via fluorescence lifetime changes. A best detection limit of 0.5% (vol) has been determined for gaseous O2 with selected ORMOCER® sensing layers. Glucose concentrations were measured to a detection limit of 0.1 mmol L-1 over a range up to 30 mmol L-1. The sensor was usable for 30 days in a bioreactor. The opto-electronic instrumentation and performance in laboratory bioreactors and in an industrial reactor are evaluated.

  13. Study of a fibre optics current sensor for the measurement of plasma current in ITER

    Science.gov (United States)

    Wuilpart, Marc; Vanus, Benoit; Andrasan, Alina; Gusarov, Andrei; Moreau, Philippe; Mégret, Patrice

    2016-05-01

    In this article, we study the feasibility of using a fibre-optics current sensor (FOCS) for the measurement of plasma current in the future fusion reactor ITER. The sensor is based on a classical FOCS interrogator involving the measurement of the state of polarization rotation undergone by the light in presence of a magnetic field (Faraday effect) in an optical fibre surrounding the current and terminated by a Faraday mirror. We considered a uniformly spun optical fibre as the sensing element and we used the Stokes formalism to simulate the sensor. The objective of the simulations is to quantify the ratio LB/SP (beat length over the spun period of the spun fibre) enabling a measurement error in agreement with the ITER specifications. The simulator takes into account the temperature variations undergone by the measurement system under ITER operation. The simulation work showed that a LB/SP ratio of 19.2 is adequate.

  14. 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.

  15. 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.

  16. 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

  17. Quantum logic operations on two distant atoms trapped in two optical-fibre-connected cavities

    Institute of Scientific and Technical Information of China (English)

    Zhang Ying-Qiao; Zhang Shou; Yeon Kyu-Hwang; Yu Seong-Cho

    2011-01-01

    Based on the coupling of two distant three-level atoms in two separate optical cavities connected with two optical fibres,schemes on the generation of several two-qubit logic gates are discussed under the conditions of △ =δ -2v cos πk/2 (》) g/2 and (v~ g).Discussion and analysis of the fidelity,gate time and experimental setups show that our schemes are feasible with current optical cavity,atomic trap and optical fibre techniques.Moreover,the atom-cavityfibre coupling can be used to generate an N-qubit nonlocal entanglement and transfer quantum information among N distant atoms by arranging N atom-cavity assemblages in a line and connecting each two adjacent cavities with two optical fibres.

  18. Remote actuation by optical power transmission in fibres

    Science.gov (United States)

    Avis, S. E.; Byron, K. C.

    1987-04-01

    Some preliminary experiments on the remote actuation of a servo-valve are described in which the power transmission medium is an optical fibre. Using a semiconductor laser or a Nd:YAG laser as the power source and silicon cells as the opto-electrical transducer, switching of the servo-valve has been observed at power levels of a few milliwatts over 800 m of fibre.

  19. Waveguidance by the photonic bandgap effect in optical fibres

    DEFF Research Database (Denmark)

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

    1999-01-01

    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...... 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...

  20. 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.

  1. Secure Communication System Basedon Chaosin Optical Fibre

    Institute of Scientific and Technical Information of China (English)

    Pak L Chu; Fan Zhang; William Mak; Robust Lai

    2003-01-01

    @@ 1 Introduction Recently, there have been intense research activities on the study of synchronized chaos generated by fibre lasers [1] and its application to secure communication systems . So far, all studies concentrate on two aspects:[2].So far,all studies concentrate on two aspects:(1) the effect of the transmission channel between the transmitter and the receiver has been neglected, and (2)the chaos and the signal are carried by one wavelength.Both theoretical and experimental investigations make these two assumptions. In the experiments, the transmission fibre is invariably short, in the order of tens of metres. Hence its dispersion and nonlinear effects are negligible. The fibre laser responsible for the generation of chaos is often designed to lase at one wavelength only.

  2. Long Optical Delay Lines Enhanced by Ring Configuration in Optical Fibres

    Institute of Scientific and Technical Information of China (English)

    DONG Yong-Kang; LU Zhi-Wei; LI Qiang; GAO Wei

    2007-01-01

    A long optically controlled delay line enhanced by ring configuration is demonstrated by using the group-velocity control of signal pulses based on stimulated Brillouin scattering. In experiment, two optical fibre ring cavities are used: one is used as the Brillouin laser, providing single-mode Stokes wave as probe wave; the other is used as the Brillouin amplifier, working as slow light medium. We achieve a maximum time delay of 215ns using the ring Brillouin amplifier, five times larger than the input probe pulse width of 40ns. In the meantime, a considerable pulse broadening is observed, which agrees well with the theoretical prediction based on linear theory.

  3. 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.

  4. 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

  5. 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.

  6. An integrating sphere radiometer as a solution for high power calibrations in fibre optics

    Science.gov (United States)

    Carrasco-Sanz, Ana; Rodríguez-Barrios, Félix; Corredera, Pedro; Martín-López, Sonia; González-Herráez, Miguel; Hernanz, María Luisa

    2006-04-01

    This paper describes the design, characterization and calibration of a high power transfer standard for optical power measurements in optical fibres based on an integrating sphere radiometer. This radiometer, based on two detectors (Si and InGaAs), can measure powers between 100 nW and 10 W within the wavelength range of (400-1700) nm. The radiometer has been calibrated over the total spectral range of use against an electrically calibrated pyroelectric radiometer and different fibre laser diodes and ion lasers. The total uncertainty obtained is lower than ±1.5% for these wavelengths and power ranges (excluding the water absorption region).

  7. 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 ...

  8. Numerical modelling of a fibre reflection filter based on a metal-dielectric diffraction structure with an increased optical damage threshold

    Science.gov (United States)

    Terentyev, V. S.; Simonov, V. A.

    2016-02-01

    Numerical modelling demonstrates the possibility of fabricating an all-fibre multibeam two-mirror reflection interferometer based on a metal-dielectric diffraction structure in its front mirror. The calculations were performed using eigenmodes of a double-clad single-mode fibre. The calculation results indicate that, using a metallic layer in the structure of the front mirror of such an interferometer and a diffraction effect, one can reduce the Ohmic loss by a factor of several tens in comparison with a continuous thin metallic film.

  9. Numerical modelling of a fibre reflection filter based on a metal–dielectric diffraction structure with an increased optical damage threshold

    Energy Technology Data Exchange (ETDEWEB)

    Terentyev, V S; Simonov, V A [Institute of Automation and Electrometry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2016-02-28

    Numerical modelling demonstrates the possibility of fabricating an all-fibre multibeam two-mirror reflection interferometer based on a metal–dielectric diffraction structure in its front mirror. The calculations were performed using eigenmodes of a double-clad single-mode fibre. The calculation results indicate that, using a metallic layer in the structure of the front mirror of such an interferometer and a diffraction effect, one can reduce the Ohmic loss by a factor of several tens in comparison with a continuous thin metallic film. (laser crystals and braggg ratings)

  10. Optical Fibre Fabry-Perot Interferometers for Calorimetric Heat Transfer Gauges

    Science.gov (United States)

    1992-12-01

    The potential advantages of a fibre optic sensor for made with the "stem on the cndwall of a cascade heat transfer measurement are 0i) high spatial...from the laser diode source to the fibre- The Measurements of heat flux using. a fibre optic - intensitv referencing scheme outlined abov’ý was...reflections and parasitic optical cavities within the platinum thin film resisitance gauges fibre optic network Such reflections were reduced b% design

  11. 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.

  12. Comparison of event-based analysis of glaucoma progression assessed subjectively on visual fields and retinal nerve fibre layer attenuation measured by optical coherence tomography.

    Science.gov (United States)

    Kaushik, Sushmita; Mulkutkar, Samyak; Pandav, Surinder Singh; Verma, Neelam; Gupta, Amod

    2015-02-01

    The purpose is to study the ability of an event-based analysis of retinal nerve fibre layer (RNFL) attenuation measured by Stratus(®) optical coherence tomography (OCT) and to detect progression across the spectrum of glaucoma. Adult glaucoma suspects, ocular hypertensives and glaucoma patients who had undergone baseline RNFL thickness measurement on Stratus OCT and reliable automated visual field examination by Humphrey's visual field analyser prior to March 2007 and had 5-year follow-up data were recruited. Progression on OCT was defined by two criteria: decrease in average RNFL thickness from baseline by at least 10 and 20 µ. Visual field progression was defined by the modified Hodapp-Parrish-Anderson criteria. Absolute and percentage change in RNFL thickness from baseline was compared in progressors and non-progressors on visual fields. Concordance between structural and functional progression was analysed. 318 eyes of 162 patients were analysed. 35 eyes (11 %) progressed by visual fields, 8 (2.5 %) progressed using the 20 µ loss criterion, while 30 eyes (9.4 %) progressed using the 10 µ loss criterion. In glaucoma suspects, mean absolute RNFL attenuation was 8.6 µ (12.1 % of baseline) in those who progressed to glaucoma by visual fields. OCT was more useful to detect progression in early glaucoma, but performed poorly in advanced glaucoma. The 10 µ criterion appears to be closer to visual field progression. However, the ability to detect progression varies considerably between functional and structural tools depending upon the severity of the disease.

  13. 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.

  14. Numerical modelling of multimode fibre-optic communication lines

    Energy Technology Data Exchange (ETDEWEB)

    Sidelnikov, O S; Fedoruk, M P [Novosibirsk State University, Novosibirsk (Russian Federation); Sygletos, S; Ferreira, F [Aston University, England, Birmingham, B4 7ET (United Kingdom)

    2016-01-31

    The results of numerical modelling of nonlinear propagation of an optical signal in multimode fibres with a small differential group delay are presented. It is found that the dependence of the error vector magnitude (EVM) on the differential group delay can be reduced by increasing the number of ADC samples per symbol in the numerical implementation of the differential group delay compensation algorithm in the receiver. The possibility of using multimode fibres with a small differential group delay for data transmission in modern digital communication systems is demonstrated. It is shown that with increasing number of modes the strong coupling regime provides a lower EVM level than the weak coupling one. (fibre-optic communication lines)

  15. Deep ultraviolet laser micromachining of novel fibre optic devices

    Energy Technology Data Exchange (ETDEWEB)

    Li, J [The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King' s College Road, Ontario M5S 3G4 (Canada); Dou, J [The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King' s College Road, Ontario M5S 3G4 (Canada); Herman, P R [The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King' s College Road, Ontario M5S 3G4 (Canada); Fricke-Begemann, T [Laser-Laboratorium Goettingen e.V., D-37077 Goettingen (Germany); Ihlemann, J [Laser-Laboratorium Goettingen e.V., D-37077 Goettingen (Germany); Marowsky, G [Laser-Laboratorium Goettingen e.V., D-37077 Goettingen (Germany)

    2007-04-15

    A deep ultraviolet F{sub 2} laser, with output at 157-nm wavelength, has been adopted for micro-shaping the end facets of single and multi-mode silica optical fibres. The high energy 7.9-eV photons drive strong interactions in the wide-bandgap silica fibres to enable the fabrication of surface-relief microstructures with high spatial resolution and smooth surface morphology. Diffraction gratings, focusing lenses, and Mach-Zehnder interferometric structures have been micromachined onto the cleaved-fibre facets and optically characterized. F{sub 2}-laser micromachining is shown to be a rapid and facile means for direct-writing of novel infibre photonic components.

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

    Directory of Open Access Journals (Sweden)

    Leslie Wong

    2016-05-01

    Full Text Available 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.

  17. Early dental caries detection using a fibre-optic coupled polarization-resolved Raman spectroscopic system.

    Science.gov (United States)

    Ko, Alex C-T; Hewko, Mark; Sowa, Michael G; Dong, Cecilia C S; Cleghorn, Blaine; Choo-Smith, Lin-P'ing

    2008-04-28

    A new fibre-optic coupled polarization-resolved Raman spectroscopic system was developed for simultaneous collection of orthogonally polarized Raman spectra in a single measurement. An application of detecting incipient dental caries based on changes observed in Raman polarization anisotropy was also demonstrated using the developed fibre-optic Raman spectroscopic system. The predicted reduction of polarization anisotropy in the Raman spectra of caries lesions was observed and the results were consistent with those reported previously with Raman microspectroscopy. The capability of simultaneous collection of parallel- and cross-polarized Raman spectra of tooth enamel in a single measurement and the improved laser excitation delivery through fibre-optics demonstrated in this new design illustrates its future clinical potential.

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

    Institute of Scientific and Technical Information of China (English)

    DUAN Sai-Liang; LI Jian-Feng; ZHAO Wei; WANG Yi-Shan

    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.

  19. Reflective variable optical attenuators and fibre ring lasers for wavelength-division multiplexing systems

    Science.gov (United States)

    Liu, He Liang

    Wavelength division multiplexing (WDM) optical fibre system is an important enabling technology to fulfill the demands for bandwidth in the modern information age. The main objective of this project is to study novel devices with the potential to enhance the performance of WDM systems. In particular, a novel reflective variable optical attenuator (RVOA) used for dynamic gain equalization (DGE) and fibre lasers based on an entirely new type of erbium-doped fibres with ultrawide tuning range were investigated theoretically and experimentally. We proposed a new type of RVOA device which could be potentially integrated with arrayed waveguide grating (AWG) to reduce the cost of DGE substantially. Initially, fibre-based RVOAs, fabricated with optical fibre components such as fibre coupler and Faraday rotator mirror, were investigated theoretically and experimentally. Larger attenuation range up to 22 dB was realized for fibre coupler-based ROVA with a Faraday rotator mirror and its polarization-dependent loss is about 0.5 dB. Then polymeric waveguide-based RVOAs were investigated theoretically and experimentally. Using an epoxy Novolak resin as core material and an UV-cured resin (Norland's NOA61) as cladding material, a polymeric waveguide RVOA was successfully fabricated. The dynamic 15 dB attenuation range was achieved and the PDL was less than 0.2 dB. The measured insertion loss of the polymeric waveguide RVOA was too large (about 18 dB) and was mainly induced by coupling loss, material loss and poor alignment. In the second part of the study, fibre ring lasers with continuous wavelength tuning over wide wavelength range and fibre ring lasers with discrete wavelength tuning were investigated. Tunable lasers are important devices in WDM systems because they could be employed as reserved sources and therefore avoiding the need to stock large inventory of lasers to cover the ITU-wavelength grid. In this project, erbium ions doped bismuth oxide glass fibres instead of

  20. 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...

  1. Fibre Optics In A Multi-Star Wideband Local Network

    Science.gov (United States)

    Fox, J. R.

    1983-08-01

    Early experience has been gained with the switched-star type of network in the Fibrevision cable TV trial at Milton Keynes, and British Telecom are progressing towards a full-scale multi-star wideband local network. This paper discusses both the present and future use of fibre optics in this type of network.

  2. FABRICATION AND APPLICATION OF NEARFIELD OPTICAL FIBRE PROBE

    Institute of Scientific and Technical Information of China (English)

    SUN JIA-LIN; XU JIAN-HUA; TIAN GUANG-YAN; GUo JI-HUA; ZHAO JUN; XIE AI-FANG; ZHANG ZE-BO

    2001-01-01

    In this paper, the fabrication of a large cone angle near-field optical fibre probe, using the two-step chemical etching method and bent probe, is introduced, and the controlling parameters of the coated Cr-Al film at the probe tip are presented. The scanning electron microscopy images display that the tip diameter of the uncoated large cone angle fibre probe obtained is less than 50nm, the cone angle over 90°, and the diameter of light aperture at the coated probe tip is less than 100nm. The measured results of the optical transmission efficiency for various probe tips show that the uncoated straight optical fibre probe, film-coated straight probe and film-coated bent probe are 3×10-1, 2×10-3, and l×10-4 times that of the flat fibre probe, respectively. In addition, the force images and near-field optical images of a standard sample are acquired using a large cone angle and film-coated bent probe.

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

    DEFF Research Database (Denmark)

    Broadway, Christian; Gallego, Daniel; Woyessa, Getinet;

    2015-01-01

    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...

  4. Distributed fibre optic strain measurements on a driven pile

    Science.gov (United States)

    Woschitz, Helmut; Monsberger, Christoph; Hayden, Martin

    2016-05-01

    In civil engineering pile systems are used in unstable areas as a foundation of buildings or other structures. Among other parameters, the load capacity of the piles depends on their length. A better understanding of the mechanism of load-transfer to the soil would allow selective optimisation of the system. Thereby, the strain variations along the loaded pile are of major interest. In this paper, we report about a field trial using an optical backscatter reflectometer for distributed fibre-optic strain measurements along a driven pile. The most significant results gathered in a field trial with artificial pile loadings are presented. Calibration results show the performance of the fibre-optic system with variations in the strain-optic coefficient.

  5. 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...

  6. 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...... temperature dependent thermo-optic coefficient, ideal for packaging of structured fibre gratings, is proposed and explored....

  7. Numerical modelling of multimode fibre-optic communication lines

    Science.gov (United States)

    Sidelnikov, O. S.; Sygletos, S.; Ferreira, F.; Fedoruk, M. P.

    2016-01-01

    The results of numerical modelling of nonlinear propagation of an optical signal in multimode fibres with a small differential group delay are presented. It is found that the dependence of the error vector magnitude (EVM) on the differential group delay can be reduced by increasing the number of ADC samples per symbol in the numerical implementation of the differential group delay compensation algorithm in the receiver. The possibility of using multimode fibres with a small differential group delay for data transmission in modern digital communication systems is demonstrated. It is shown that with increasing number of modes the strong coupling regime provides a lower EVM level than the weak coupling one.

  8. EDITORIAL: The 19th International Conference on Optical Fibre Sensors, OFS-19 The 19th International Conference on Optical Fibre Sensors, OFS-19

    Science.gov (United States)

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

    2009-03-01

    OFS-19 was held in April 2008 in Perth, Australia, with Professor David Sampson (University of Western Australia) as General Chair assisted by Technical Programme Co-Chairs Professor Stephen Collins (Victoria University, Australia), Professor Kyunghwan Oh (Yonsei University, Korea) and Dr Ryozo Yamauchi (Fujikura Ltd, Japan). 'OFS-19' has once again affirmed the OFS series 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-19 demonstrated the continuing vigour of the community, with some 240 papers presented, plus 8 tutorials; submissions and attendance were from 29 countries, with a little over half coming from the Asia-Pacific Region. In recent years, it has become a tradition to publish a post-conference special issue in Measurement Science and Technology, and these special issues offer a representative sample of the current status of the field. In the 25 years since OFS began, many of the early ideas and laboratory-based proof-of-principle experiments have successfully evolved into highly developed instrumentation systems and commercial products. One of the greatest success stories has been the optical fibre Bragg grating. Its exquisite intrinsic sensitivity to temperature and strain has led to an expanding niche in structural monitoring, especially in civil engineering. It has formed the 'beach-head' for penetration of optical fibre sensors into the oil and gas industry, initially in the harsh environment of down-hole monitoring. Latterly, it has paved the way for new applications of one of the earliest fibre optic sensors, the fibre hydrophone, which is now making its mark in sub-sea seismic surveying. Additionally

  9. Simple method for manufacturing and optical characterization of tapered optical fibres

    Science.gov (United States)

    Zakrzewski, A.; Pięta, A.; Patela, S.

    2016-12-01

    Photonic devices often use light delivered by a single-mode telecommunication fibre. However, as the diameter of the core of the optical fibre is of 10 microns, and the transverse dimensions of the photonic waveguides are usually micrometer or less, there is an issue of incompatibility. The problem may be solved by application of tapered optical fibres. For efficient light coupling, the taper should be prepared so as to create a beam of long focal length and small spot diameter in the focus. The article describes the design, fabrication and characterization of tapered optical fibres prepared with a fibre-optic fusion splicer. We modelled the tapers with FDTD method, for estimation of the influence of the tapered length and angle on the spot diameter and the focal length of an outgoing beam. We fabricated tapers from a standard single mode fibre by the Ericsson 995 PMfi- bre-optic fusion splicer. We planned the splicing technology so as to get the needed features of the beam. We planned a multistep fusion process, with optimized fusion current and fusion time. The experimental measurements of best tapered optical fibres were carried out by the knife-edge method.

  10. Programmable logic controller optical fibre sensor interface module

    Science.gov (United States)

    Allwood, Gary; Wild, Graham; Hinckley, Steven

    2011-12-01

    Most automated industrial processes use Distributed Control Systems (DCSs) or Programmable Logic Controllers (PLCs) for automated control. PLCs tend to be more common as they have much of the functionality of DCSs, although they are generally cheaper to install and maintain. PLCs in conjunction with a human machine interface form the basis of Supervisory Control And Data Acquisition (SCADA) systems, combined with communication infrastructure and Remote Terminal Units (RTUs). RTU's basically convert different sensor measurands in to digital data that is sent back to the PLC or supervisory system. Optical fibre sensors are becoming more common in industrial processes because of their many advantageous properties. Being small, lightweight, highly sensitive, and immune to electromagnetic interference, means they are an ideal solution for a variety of diverse sensing applications. Here, we have developed a PLC Optical Fibre Sensor Interface Module (OFSIM), in which an optical fibre is connected directly to the OFSIM located next to the PLC. The embedded fibre Bragg grating sensors, are highly sensitive and can detect a number of different measurands such as temperature, pressure and strain without the need for a power supply.

  11. Wide-Band Optical Fibre System for Investigation of MEMS and NEMS Deflection

    Directory of Open Access Journals (Sweden)

    Orłowska Karolina

    2014-08-01

    Full Text Available In this work the construction of experimental setup for MEMS/NEMS deflection measurements is presented. The system is based on intensity fibre optic detector for linear displacement sensing. Furthermore the electronic devices: current source for driving the light source and photodetector with wide-band preamplifier are presented.

  12. 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.

  13. 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.

  14. High resolution fibre optic length and extension measurement; Hochaufloesende faseroptische Laengen- und Ausdehnungsmessung

    Energy Technology Data Exchange (ETDEWEB)

    Doering, H. [Hochschule fuer Technik und Wirtschaft Mittweida (FH) (Germany)

    2007-07-01

    A monitoring system to observe the total length of an optical fibre integrated in building or environmental structures has been developed. The system is particularly suitable for fibres with a length of several meters to several kilometres. The system has been developed for optical fibres but is applicable to electrical cables as well. (orig.)

  15. Role of the interface between distributed fibre optic strain sensor and soil in ground deformation measurement

    Science.gov (United States)

    Zhang, Cheng-Cheng; Zhu, Hong-Hu; Shi, Bin

    2016-11-01

    Recently the distributed fibre optic strain sensing (DFOSS) technique has been applied to monitor deformations of various earth structures. However, the reliability of soil deformation measurements remains unclear. Here we present an integrated DFOSS- and photogrammetry-based test study on the deformation behaviour of a soil foundation model to highlight the role of strain sensing fibre–soil interface in DFOSS-based geotechnical monitoring. Then we investigate how the fibre–soil interfacial behaviour is influenced by environmental changes, and how the strain distribution along the fibre evolves during progressive interface failure. We observe that the fibre–soil interfacial bond is tightened and the measurement range of the fibre is extended under high densities or low water contents of soil. The plastic zone gradually occupies the whole fibre length when the soil deformation accumulates. Consequently, we derive a theoretical model to simulate the fibre–soil interfacial behaviour throughout the progressive failure process, which accords well with the experimental results. On this basis, we further propose that the reliability of measured strain can be determined by estimating the stress state of the fibre–soil interface. These findings may have important implications for interpreting and evaluating fibre optic strain measurements, and implementing reliable DFOSS-based geotechnical instrumentation.

  16. An SMS structure based temperature sensor using a chalcogenide multimode fibre

    Science.gov (United States)

    Wang, Pengfei; Yuan, Libo; Brambilla, Gilberto; Farrell, Gerald

    2016-11-01

    In this work we investigated the fabrication of a singlemode-multimode-singlemode (SMS) fibre structure based on a chalcogenide (As2S3 and AsxS1-x) multimode fibre (MMF) sandwiched between two standard silica singlemode fibres (SMFs) using a commercial fibre fusion splicer. The temperature dependence of this hybrid fibre structure was also investigated. A first proof of concept showed that the hybrid SMS fibre structure has an average experimental temperature sensitivity of 50.63 pm/°C over a temperature range of 20 °C 100°C at wavelengths around 1.55 μm. The measured results show a general agreement with numerical simulations based on a guided-mode propagation analysis method. Our result provides a potential platform for the development of compact, high-optical-quality and robust sensing devices operating at the mid-infrared wavelength range.

  17. A Lower Bound on the per Soliton Capacity of the Nonlinear Optical Fibre Channel

    CERN Document Server

    Shevchenko, Nikita A; Derevyanko, Stanislav A; Alvarado, Alex; Bayvel, Polina; Turitsyn, Sergei K

    2015-01-01

    A closed-form expression for a lower bound on the per soliton capacity of the nonlinear optical fibre channel in the presence of (optical) amplifier spontaneous emission (ASE) noise is derived. This bound is based on a non-Gaussian conditional probability density function for the soliton amplitude jitter induced by the ASE noise and is proven to grow logarithmically as the signal-to-noise ratio increases.

  18. Optical fibre probes in the measurement of scattered light: Application for sensing turbidity

    Indian Academy of Sciences (India)

    M R Sheno

    2014-01-01

    Optical fibre probes or optrodes often form the heart of multimode fibre-based measurements 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 light reflected/scattered/fluoresced from the sample containing the measurand(s). The so-collected light carries the characteristic signature of the measurand. Here we present our work on the design and realization of optrodes for the measurement of scattered light from liquid samples. Optical properties of a solution are usually characterized by the parameters absorption coefficient $_a$, scattering coefficient $_s$, and anisotropy factor . We have developed a simple method to determine $_a$, $_s$, and , of a turbid medium, and a Monte–Carlo model was used to simulate the light scattering from the turbid medium. As an application, we describe the development of a turbidity sensor that has been designed and realized by employing an optrode in conjunction with a concave mirror. The estimation of turbidity is done on the basis of total interaction, by considering scattering and absorption of light from the sample solution. Details of the experiments and results are presented here.

  19. Small prototype gamma camera based on wavelength-shifting fibres

    Science.gov (United States)

    Castro, I. F.; Soares, A. J.; Moutinho, L. M.; Veloso, J. F. C. A.

    2012-01-01

    We are studying and developing a small field of view gamma camera based on wavelength-shifting optical fibres coupled to both sides of an inorganic scintillation crystal and using for the light readout highly sensitive photon detectors, namely silicon photomultipliers (SiPMs) and high efficiency multi-anode photomultiplier tubes (MaPMTs). The coupling of the fibres in orthogonal directions allows obtaining 2D position information, while the energy signal is provided by a PMT. A first prototype laboratory system has been developed using a custom-made 50 × 50 × 3 mm3 CsI(Na) crystal with embedded 1 mm diameter fibres and reading out the light from several fibres in each direction, both with individual SiPMs and with a MaPMT. Proof-of-concept studies and results obtained with these systems using 57Co are presented and compared. The application of optical fibres combined with highly sensitive SiPMs or MaPMTs as light sensors in a compact gamma camera has the potential to improve the spatial resolution to the 1-2 mm FWHM level, thus improving the sensitivity of typical scintigraphy techniques and making such camera clinically useful. Results demonstrate the feasibility and imaging capability of the system using both types of photon detectors for imaging. In the case of SiPMs, a temperature cooling system is necessary to improve the SNR and consequently achieve a better imaging performance. The development of larger prototypes with 10 × 10 cm2 and 12 × 12 cm2 is under way, using 1 mm2 SiPMs and 64 anode PMTs, respectively.

  20. Synchronously pumped picosecond all-fibre Raman laser based on phosphorus-doped silica fibre.

    Science.gov (United States)

    Kobtsev, Sergey; Kukarin, Sergey; Kokhanovskiy, Alexey

    2015-07-13

    Reported for the first time is picosecond-range pulse generation in an all-fibre Raman laser based on P₂O₅-doped silica fibre. Employment of phosphor-silicate fibre made possible single-cascade spectral transformation of pumping pulses at 1084 nm into 270-ps long Raman laser pulses at 1270 nm. The highest observed fraction of the Stokes component radiation at 1270 nm in the total output of the Raman laser amounted to 30%. The identified optimal duration of the input pulses at which the amount of Stokes component radiation in a ~16-m long phosphorus-based Raman fibre converter reaches its maximum was 140-180 ps.

  1. 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)....

  2. Plastic optical fibre sensor for quality control in food industry

    Science.gov (United States)

    Novo, C.; Bilro, L.; Ferreira, R.; Alberto, N.; Antunes, P.; Leitão, C.; Nogueira, R.; Pinto, J. L.

    2013-05-01

    The present work addresses the need for new devices felt in the context of quality control, especially in the food industry. Due to the spectral dependence of the attenuation coefficient, a novel dual-parameter sensor for colour and refractive index was developed and tested. The sensor employs plastic optical fibres to measure the transmitted optical power in three measurement cells each with a different incident wavelength. The performance of the sensor was tested using several dyes at different concentrations and aqueous solutions of glycerine and ethanol. Results show that this technique allows the monitoring of refractive index and colour without cross-sensitivity.

  3. Preliminary research on monitoring the durability of concrete subjected to sulfate attack with optical fibre Raman spectroscopy

    Science.gov (United States)

    Yue, Yanfei; Bai, Yun; Basheer, P. A. Muhammed; Boland, John J.; Wang, Jing Jing

    2013-04-01

    Formation of ettringite and gypsum from sulfate attack together with carbonation and chloride ingress have been considered as the most serious deterioration mechanisms of concrete structures. Although Electrical Resistance Sensors and Fibre Optic Chemical Sensors could be used to monitoring the latter two mechanisms in situ, currently there is no system for monitoring the deterioration mechanisms of sulfate attack and hence still needs to be developed. In this paper, a preliminary study was carried out to investigate the feasibility of monitoring the sulfate attack with optical fibre Raman spectroscopy through characterizing the ettringite and gypsum formed in deteriorated cementitious materials under an `optical fibre excitation + spectroscopy objective collection' configuration. Bench-mounted Raman spectroscopy analysis was also used to validate the spectrum obtained from the fibre-objective configuration. The results showed that the expected Raman bands of ettringite and gypsum in the sulfate attacked cement paste have been clearly identified by the optical fibre Raman spectroscopy and are in good agreement with those identified from bench-mounted Raman spectroscopy. Therefore, based on these preliminary results, there is a good potential of developing an optical fibre Raman spectroscopy-based system for monitoring the deterioration mechanisms of concrete subjected to the sulfate attack in the future.

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

    Science.gov (United States)

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

    2013-09-01

    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.

  5. Fibre optic system for monitoring rotational seismic phenomena.

    Science.gov (United States)

    Kurzych, Anna; Jaroszewicz, Leszek R; Krajewski, Zbigniew; Teisseyre, Krzysztof P; Kowalski, Jerzy K

    2014-03-19

    We outline the development and the application in a field test of the Autonomous Fibre-Optic Rotational Seismograph (AFORS), which utilizes the Sagnac effect for a direct measurement of the seismic-origin rotations of the ground. The main advantage of AFORS is its complete insensitivity to linear motions, as well as a direct measurement of rotational components emitted during seismic events. The presented system contains a special autonomous signal processing unit which optimizes its operation for the measurement of rotation motions, whereas the applied telemetric system based on the Internet allows for an AFORS remote control. The laboratory investigation of such two devices indicated that they keep an accuracy of no less than 5.1 × 10(-9) to 5.5 × 10(-8) rad/s in the detection frequency band from 0.83~106.15 Hz and protect linear changes of sensitivity in the above bandpass. Some experimental results of an AFORS-1 application for a continuous monitoring of the rotational events in the Książ (Poland) seismological observatory are also presented.

  6. Fibre Optic System for Monitoring Rotational Seismic Phenomena

    Directory of Open Access Journals (Sweden)

    Anna Kurzych

    2014-03-01

    Full Text Available We outline the development and the application in a field test of the Autonomous Fibre-Optic Rotational Seismograph (AFORS, which utilizes the Sagnac effect for a direct measurement of the seismic-origin rotations of the ground. The main advantage of AFORS is its complete insensitivity to linear motions, as well as a direct measurement of rotational components emitted during seismic events. The presented system contains a special autonomous signal processing unit which optimizes its operation for the measurement of rotation motions, whereas the applied telemetric system based on the Internet allows for an AFORS remote control. The laboratory investigation of such two devices indicated that they keep an accuracy of no less than 5.1 × 10−9 to 5.5 × 10−8 rad/s in the detection frequency band from 0.83~106.15 Hz and protect linear changes of sensitivity in the above bandpass. Some experimental results of an AFORS-1 application for a continuous monitoring of the rotational events in the Książ (Poland seismological observatory are also presented.

  7. A method to remove residual signals in fibre optic luminescence dosimeters.

    Science.gov (United States)

    Lee, J J; Liu, P Z Y; McKenzie, D R; Suchowerska, N

    2013-03-07

    Whenever a fibre optic is used to convey a light signal through a radiation field, it is likely that an unwanted background signal will arise from Cerenkov or fluorescent light which will contaminate the signal. In luminescence dosimetry of high energy beams, when a fibre optic is used to convey the signal from the radiation field to the detector, Cerenkov light is the dominant contributor to the background signal and must be corrected for. In this work, a novel method is demonstrated to separate the signal from the unwanted background. A remotely operated shutter is used to block the signal, allowing the residual background in the fibre optic to be quantified. This background is subtracted from the total measurement acquired in a subsequent irradiation, enabling the luminescence signal to be extracted. Two types of shutter mechanism are considered: an electro-mechanical device to intercept the light path and an LCD device to block the light by cross-polarization. Both shutters were characterized and incorporated into a fibre optic dosimetry system used to measure the radiation dose produced by external beam radiation linear accelerators. The dosimeter using each of the shutters in turn was exposed to a 6 MV photon beam to determine their performance, including the measurement of field size dependent output factors. The mechanical shutter determined the output factors to within 0.29% of those measured with an ionization chamber, whereas the LCD shutter gave results that deviated by up to 2.4%. The switching precision of both shutters was good with standard deviations of less than 0.25% and both were able to completely block the light signal when closed. The use of shutters could therefore be applied to any fibre optic based system to quantify and remove a reproducible background arising from any source including ambient, fluorescent and Cerenkov light.

  8. Yb3+-Doped Double-Clad Fibre Laser Based on Fibre Bragg Grating

    Institute of Scientific and Technical Information of China (English)

    范万德; 付圣贵; 张强; 宁鼎; 李丽君; 王志; 袁树忠; 董孝义

    2003-01-01

    A novel Yb3+-doped double-clad fibre laser based on a double-clad fibre Bragg grating is presented. The fibre Bragg grating, as the output mirror, has been formed in Yb3+-doped double-clad fibre with the phase-mask method. When the input pump power is 2.8 W, the maximum laser output power is 570mW, with < 0.2 nm in line-width at the wavelength of 1.058μm, over 40dB signal-to-noise ratio and 24% slope efficiency.

  9. Quantum storage of entangled telecom-wavelength photons in an erbium-doped optical fibre

    CERN Document Server

    Saglamyurek, Erhan; Verma, Varun B; Shaw, Matthew D; Marsili, Francesco; Nam, Sae Woo; Oblak, Daniel; Tittel, Wolfgang

    2014-01-01

    The realization of a future quantum Internet requires processing and storing quantum information at local nodes, and interconnecting distant nodes using free-space and fibre-optic links. Quantum memories for light are key elements of such quantum networks. However, to date, neither an atomic quantum memory for non-classical states of light operating at a wavelength compatible with standard telecom fibre infrastructure, nor a fibre-based implementation of a quantum memory has been reported. Here we demonstrate the storage and faithful recall of the state of a 1532 nm wavelength photon, entangled with a 795 nm photon, in an ensemble of cryogenically cooled erbium ions doped into a 20 meter-long silicate fibre using a photon-echo quantum memory protocol. Despite its currently limited efficiency and storage time, our broadband light-matter interface brings fibre-based quantum networks one step closer to reality. Furthermore, it facilitates novel tests of light-matter interaction and collective atomic effects in u...

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

    CERN Document Server

    CooK, Kevin; 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.

  11. Optical Fibre Embedded in a Composite Laminated with Applications to Sensing

    Science.gov (United States)

    2000-09-29

    The possibility of using fibre optic instrumented plates in rehabilitation of civil structures was demonstrated, since strain measurements and...125-157, 1993. [4] W. W. Morey, G. Meltz, and W. H. Glenn, " Fibre optic bragg grating sensors", in Fiber Optic and Laser Sensors VII, in Proc. SPIE 1169, Boston, USA, pp. 98-107, 1989.

  12. Long-term stability of fibre-optic transmission for multi-object spectroscopy

    CERN Document Server

    Sharp, R; Cannon, R D

    2012-01-01

    We present an analysis of the long-term stability of fibre-optic transmission properties for fibre optics in astronomy. Data from six years of operation of the AAOmega multi-object spectrograph at the Anglo-Australian Telescope is presented. We find no evidence for significant degradation in the bulk transmission properties of the 38 m optical fibre train. Significant losses (<20% relative, 4% absolute) are identified and associated with the end termination of the optical fibres in the focal plane. Improved monitoring and maintenance can rectify the majority of this performance degradation.

  13. Femtosecond laser induced refractive index structures in polymer optical fibre (POF) for sensing

    Science.gov (United States)

    Liang, S. J.; Scully, P. J.; Schille, J.; Vaughan, J.; Perrie, W.

    2009-10-01

    Techniques to directly write localised refractive index structures in polymer optical fibres (POF) are presented, using UV (400nm) ultrafast laser with pulse lengths of 100 fs to create in-fibre gratings for sensing. No doping is necessary for photosensitisation so commercially available POF is used. An in-fibre grating consisting of a 1.8 μm wide refractive index structure with a periodicity of 189 nm was demonstrated in single mode polymer fibre with optimised laser processing parameters.

  14. Efficient delivery of 60 J pulse energy of long pulse Nd:YAG laser through 200 m core diameter optical fibre

    Indian Academy of Sciences (India)

    Ravindra Singh; Ambar Choubey; R K Jain; S C Vishwakarma; D K Agrawal; Sabir Ali; B N Upadhyaya; S M Oak

    2014-02-01

    Most of today’s industrial Nd:YAG lasers use fibre-optic beam delivery. In such lasers, fibre core diameter is an important consideration in deploying a beam delivery system. Using a smaller core diameter fibre allows higher irradiances at focus position, less degradation of beam quality, and a larger stand-off distance. In this work, we have put efforts to efficiently deliver the laser output of ‘ceramic reflector’-based long pulse Nd:YAG laser through a 200 m core diameter optical fibre and successfully delivered up to 60 J of pulse energy with 90% transmission efficiency, using a GRADIUM (axial gradient) plano-convex lens to sharply focus down the beam on the end face of the optical fibre and fibre end faces have been cleaved to achieve higher surface damage thresholds.

  15. Novel technique for distributed fibre sensing based on coherent Rayleigh scattering measurements of birefringence

    Science.gov (United States)

    Lu, Xin; Soto, Marcelo A.; Thévenaz, Luc

    2016-05-01

    A novel distributed fibre sensing technique is described and experimentally validated, based on birefringence measurements using coherent Rayleigh scattering. It natively provides distributed measurements of temperature and strain with more than an order of magnitude higher sensitivity than Brillouin sensing, and requiring access to a single fibre-end. Unlike the traditional Rayleigh-based coherent optical time-domain reflectometry, this new method provides absolute measurements of the measurand and may lead to a robust discrimination between temperature and strain in combination with another technique. Since birefringence is purposely induced in the fibre by design, large degrees of freedom are offered to optimize and scale the sensitivity to a given quantity. The technique has been validated in 2 radically different types of birefringent fibres - elliptical-core and Panda polarization-maintaining fibres - with a good repeatability.

  16. A simple and inexpensive optical power monitor for two visible wavelength WDM channels in plastic optical fibre links

    Science.gov (United States)

    Freitas, Taiane A. M. G.; Marcondes, Claudia B.; Ribeiro, Ricardo M.

    2016-12-01

    This paper shows for the first time, to the best of our knowledge, the design of a simple, non-invasive, bidirectional and inexpensive optical power monitor (OPMo) for WDM over PMMA-based polymer optical fibre (POF) links transmitting 470 nm and 650 nm wavelengths light carriers. Low-cost cellophane plastic optical filters were used for each WDM channel aiming to demonstrate the OPMo operational principle. The OPMo is non-invasive because it does not tap any guided light from the fibre core; rather, it collects and detects the spontaneous side-scattered light. A sensitivity of  -32 dBm and dynamic range of 38.8 dB were measured. A crosstalk rejection better than 25 dB was achieved when both light carriers are of the same power.

  17. Real-time optical-fibre luminescence dosimetry for radiotherapy: physical characteristics and applications in photon beams

    DEFF Research Database (Denmark)

    Aznar, M.C.; Andersen, C.E.; Bøtter-Jensen, L.;

    2004-01-01

    A new optical-fibre radiation dosimeter system, based on radioluminescence and optically stimulated luminescence from carbon-doped aluminium oxide, was developed and tested in clinical photon beams. This prototype offers several features, such as a small detector (1 x 1 x 2 mm), high sensitivity...

  18. Modern fibre-optic coherent lidars for remote sensing

    Science.gov (United States)

    Hill, Chris

    2015-10-01

    This paper surveys some growth areas in optical sensing that exploit near-IR coherent laser sources and fibreoptic hardware from the telecoms industry. Advances in component availability and performance are promising benefits in several military and commercial applications. Previous work has emphasised Doppler wind speed measurements and wind / turbulence profiling for air safety, with recent sharp increases in numbers of lidar units sold and installed, and with wider recognition that different lidar / radar wavebands can and should complement each other. These advances are also enabling fields such as microDoppler measurement of sub-wavelength vibrations and acoustic waves, including non-lineof- sight acoustic sensing in challenging environments. To shed light on these different applications we review some fundamentals of coherent detection, measurement probe volume, and parameter estimation - starting with familiar similarities and differences between "radar" and "laser radar". The consequences of changing the operating wavelength by three or four orders of magnitude - from millimetric or centimetric radar to a typical fibre-optic lidar working near 1.5 μm - need regular review, partly because of continuing advances in telecoms technology and computing. Modern fibre-optic lidars tend to be less complicated, more reliable, and cheaper than their predecessors; and they more closely obey the textbook principles of easily adjusted and aligned Gaussian beams. The behaviours of noises and signals, and the appropriate processing strategies, are as expected different for the different wavelengths and applications. For example, the effective probe volumes are easily varied (e.g. by translating a fibre facet) through six or eight orders of magnitude; as the average number of contributing scatterers varies, from >1, we should review any assumptions about "many" scatterers and Gaussian statistics. Finally, some much older but still relevant scientific work (by A G Bell, E H

  19. 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…

  20. 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.

  1. 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...

  2. Photonic Crystal Fibres as the Transmission Medium for Future Optical Communication Systems

    DEFF Research Database (Denmark)

    Zsigri, Beata

    2006-01-01

    the large birefringence of AG-PBGFs, realised in only 2.4 m AG PBGF for demodulation of 9.95 and 39.8 Gbit/s di®erential phase shift keying modulated signals is demonstrated, thereby demonstrating the feasibility of AG-PBGF for realising stable and compact fibre birefringence based optical devices....... and index guiding PCFs. Nevertheless, both PCF types exhibit numerous novel properties { not obtainable by standard fibre technology { that are very attractive for optical communication systems. Even though PCFs have now existed already for a decade, their exploitation for telecommunication applications has...... carried on a single wavelength is increased to 80 Gbit/s, the highest capacity transmitted on a single wavelength over PCF today, by polarisation multiplexed differential phase shift keying signal transmission. Index guiding PCFs have also been studied for signal processing applications as well...

  3. Plastic optical fibre sensor for in-vivo radiation monitoring during brachytherapy

    Science.gov (United States)

    Woulfe, P.; Sullivan, F. J.; Lewis, E.; O'Keeffe, S.

    2015-09-01

    An optical fibre sensor is presented for applications in real-time in-vivo monitoring of the radiation dose a cancer patient receives during seed implantation in Brachytherapy. The sensor is based on radioluminescence whereby radiation sensitive scintillation material is embedded in the core of a 1mm plastic optical fibre. Three scintillation materials are investigated: thallium-doped caesium iodide (CsI:Tl), terbium-doped gadolinium oxysulphide (Gd2O2S:Tb) and europium-doped lanthanum oxysulphide (La2O2S:Eu). Terbium-doped gadolinium oxysulphide was identified as being the most suitable scintillator and further testing demonstrates its measureable response to different activities of Iodine-125, the radio-active source commonly used in Brachytherapy for treating prostate cancer.

  4. Multichannel optical-fibre heterodyne interferometer for ultrasound detection of partial discharges in power transformers

    Science.gov (United States)

    Posada, J. E.; Garcia-Souto, J. A.; Rubio-Serrano, J.

    2013-09-01

    A multichannel interferometric system is proposed for the ultrasonic detection of partial discharges using intrinsic optical fibre sensors that may be immersed in oil. It is based on a heterodyne scheme which drives at least four sensor heads in order to localize the source of the acoustic emissions. Proper design of the sensing head improves its sensitivity through magnification and reaches a compact encapsulated probe able to be installed within power transformers. The optoelectronic implementation and the experimental tests are presented to optimize the resolution (4 channels—4 mrad). In addition, the results of ultrasound measurements at 150 kHz with an optical fibre sensor immersed in water in an acoustic test bench are shown, in which a resolution better than 10 Pa was obtained. Finally, the set-up for three-phase power transformers is demonstrated and characterized to detect and locate the source of acoustic emissions.

  5. Fibre Optic Readout of Microcantilever Arrays for Fast Microorganism Growth Detection

    Directory of Open Access Journals (Sweden)

    N. Maloney

    2012-01-01

    Full Text Available We present a fibre-optic-based device for the automated readout of microcantilever arrays for fast microorganism growth detection. We determined the ability of our device to track shifts in resonance frequency due to an increase in mass on the cantilever surface or changes in mechanical stiffness. The resonance frequency response of 7 μm thick agarose-functionalised cantilevers was tracked as humidity levels were varied revealing a mass responsivity of ~51±1 pg/Hz. The resonance response of microcantilevers coated with Aspergillus niger (A. niger spores was monitored for >48 h revealing a growth detection time of >4 h. The growth of mycelium along the cantilevers surface is seen to result in an increase in resonance frequency due to the reinforcement of the cantilever structure. The use of our fibre optic detection technique allows data to be recorded continuously and faster than previously reported.

  6. Fibre optic surface plasmon resonance sensor system designed for smartphones.

    Science.gov (United States)

    Bremer, Kort; Roth, Bernhard

    2015-06-29

    A fibre optic surface plasmon resonance (SPR) sensor system for smartphones is reported, for the first time. The sensor was fabricated by using an easy-to-implement silver coating technique and by polishing both ends of a 400 µm optical fibre to obtain 45° end-faces. For excitation and interrogation of the SPR sensor system the flash-light and camera at the back side of the smartphone were employed, respectively. Consequently, no external electrical components are required for the operation of the sensor system developed. In a first application example a refractive index sensor was realised. The performance of the SPR sensor system was demonstrated by using different volume concentrations of glycerol solution. A sensitivity of 5.96·10(-4) refractive index units (RIU)/pixel was obtained for a refractive index (RI) range from 1.33 to 1.36. In future implementations the reported sensor system could be integrated in a cover of a smartphone or used as a low-cost, portable point-of-care diagnostic platform. Consequently it offers the potential of monitoring a large variety of environmental or point-of-care parameters in combination with smartphones.

  7. 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...

  8. 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

  9. An in vitro comparison of the ability of fibre-optic transillumination, visual inspection and radiographs to detect occlusal caries and evaluate lesion dept

    DEFF Research Database (Denmark)

    Ekstrand, K.R.; Côrtes, D.F.; Elias-Boneta, A.R.

    2000-01-01

    Occlusal caries, diagnosis, fibre-optic transillumination, bite-wing radiograph, visual inspection......Occlusal caries, diagnosis, fibre-optic transillumination, bite-wing radiograph, visual inspection...

  10. Polarization Drift Channel Model for Coherent Fibre-Optic Systems

    CERN Document Server

    Czegledi, Cristian B; Agrell, Erik; Johannisson, Pontus

    2015-01-01

    A theoretical framework is introduced to model the dynamical changes of the state of polarization during transmission in coherent fibre-optic systems. The model generalizes the one-dimensional phase noise random walk to higher dimensions, accounting for random polarization drifts. The model is described in the Jones, Stokes and real 4-dimensional formalisms, and the mapping between them is derived. Such a model will be increasingly important in simulating and optimizing future optical systems, which to a higher and higher degree rely on transmission and detection on both polarizations jointly using sophisticated digital signal processing. Such analysis cannot be carried out using the more rudimentary polarization drift models in use today, which only account for deterministic effects. The proposed polarization drift model is the first of its kind and will likely be useful in a wide-range of photonics applications where stochastic polarization fluctuation is an issue.

  11. 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).

  12. 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.

  13. Macro-Bending Influence on Radiation Induced Attenuation Measurement in Optical Fibres

    CERN Document Server

    Guillermain, E; Ricci, D; Weinand, U

    2014-01-01

    Influence of the bending radius on the measurement of radiation induced attenuation in glass optical fibres is discussed in this paper. Radiation induced attenuation measured in two single-mode fibre types shows discrepancies when coiled around a low bending radius spool: the observed attenuation is lower than expected. A series of dedicated tests reveals that this invalid measurement is related to the displacement of the mode field towards the cladding when the fibre is bent with a low radius, and to the different radiation resistances of the core and cladding glasses. For irradiation tests of optical fibres, the spool radius should therefore be carefully chosen.

  14. 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

    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...

  15. Optical absorption in commercial single mode optical fibres for the LHC machine

    CERN Document Server

    Wijnands, T J; Kuhnhenn, J; Hoeffgen, S K; Weinand, U; TS

    2007-01-01

    The optical absorption of light at 1310 nm and 1550 nm in various commercially available Single Mode (SM) fibres samples has been studied. The absorption was measured as a function of dose, dose rate, temperature and light power. The samples were irradiated with gamma rays from a 60Co source and exposed to a complex radiation field from high energy physics. One fibre sample with an F-doped core exhibits extreme low absorption of light at 1310 nm during irradiation up to doses of at least 100 kGy.

  16. Pulse Compression And Raman Amplification In Optical Fibres

    Science.gov (United States)

    Byron, Kevin C.

    1988-06-01

    Experimental and theoretical investigations on Raman amplification in fibres have been carried out and simultaneous amplification and pulse compression observed. With a fibre design optimised for amplification high gain may be obtained at practical pump power levels.

  17. Access Protocol For An Industrial Optical Fibre LAN

    Science.gov (United States)

    Senior, John M.; Walker, William M.; Ryley, Alan

    1987-09-01

    A structure for OSI levels 1 and 2 of a local area network suitable for use in a variety of industrial environments is reported. It is intended that the LAN will utilise optical fibre technology at the physical level and a hybrid of dynamically optimisable token passing and CSMA/CD techniques at the data link (IEEE 802 medium access control - logical link control) level. An intelligent token passing algorithm is employed which dynamically allocates tokens according to the known upper limits on the requirements of each device. In addition a system of stochastic tokens is used to increase efficiency when the stochastic traffic is significant. The protocol also allows user-defined priority systems to be employed and is suitable for distributed or centralised implementation. The results of computer simulated performance characteristics for the protocol using a star-ring topology are reported which demonstrate its ability to perform efficiently with the device and traffic loads anticipated within an industrial environment.

  18. Design of LTE Indoor MIMO Repeater System Architecture Based On Single Fibre-optical Bidirectional Transmission%基于单纤双向传输的LTE室内MIMO中继系统架构研究与设计

    Institute of Scientific and Technical Information of China (English)

    李广

    2014-01-01

    简述并分析了目前2G、3G和4G移动通信室内中继设备及系统的优势和弊端,提出了基于单纤双向传输的LTE室内MIMO中继系统架构设计,并分析了其组网架构的优势。%In the paper, I analysed the advantages and disadvantages of the current 2G, 3G and 4G indoor distributed mobile communication system, we proposed the LTE indoor MIMO repeater system architecture , which based on single optical fibre bidirectional transmission, and we give its advantages.

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

    CERN Document Server

    Cook, Kevin; 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.

  20. Self-Induced Optical Rotation of Solitons in a Chiral Fibre

    Institute of Scientific and Technical Information of China (English)

    李俊庆; 李社; 王晓鸥; 郑仰东; 李淳飞

    2004-01-01

    From Maxwell's equations and macroscopic polarization, we obtain the wave equations describing the propagation of strong light in an isotopic chiral fibre with weak spatial dispersion. By considering the possible nonlinear and dispersive effects, the nonlinear Schrodinger equations for the left- and right-circularly polarized components are derived. The mechanism to form the chiral optical solitons is discussed. The self-induced optical rotation of solitons in the chiral fibre is emphasized. An all-optical switch is proposed.

  1. March of the Starbugs: Configuring Fibre-bearing Robots on the UK-Schmidt Optical Plane

    CERN Document Server

    Lorente, Nuria P F; Satorre, Christophe; Hong, Sungwook E; Shortridge, Keith; Goodwin, Michael; Kuehn, Kyler

    2015-01-01

    The TAIPAN instrument, currently being developed for the Australian Astronomical Observatory's UK Schmidt telescope at Siding Spring Observatory, makes use of the AAO's Starbug technology to deploy 150 science fibres to target positions on the optical plane. This paper describes the software system for controlling and deploying the fibre-bearing Starbug robots. The TAIPAN software is responsible for allocating each Starbug to its next target position based on its current position and the distribution of targets, finding a collision-free path for each Starbug, and then simultaneously controlling the Starbug hardware in a closed loop, with a metrology camera used to determine the position of each Starbug in the field during reconfiguration. The software is written in C++ and Java and employs a DRAMA middleware layer (Farrell et al. 1995).

  2. Soliton fission and supercontinuum generation in photonic crystal fibre for optical coherence tomography application

    Indian Academy of Sciences (India)

    K Porsezian; R Vasantha Jayakantha Raja

    2015-11-01

    We present a practical design of novel photonic crystal fibre (PCF) to investigate the nonlinear propagation of femtosecond pulses for the application of optical coherence tomography (OCT) based on supercontinuum generation (SCG) process. In addition, this paper contains a brief introduction of the physical phenomena of soliton and SCG. Typically, here we discuss how the ultrabroadband radiation in PCF can be generated by SCG through various nonlinear effects of the fibre. To accomplish the proposed aim, we put forth liquid core PCF (LCPCF) structure filled with chloroform for OCT measurements of the eye. From the proposed design, we observe that proposed LCPCFs with liquid material exhibit significant broadened wavelength spectrum with low input pulse energy over small propagation distances for the OCT application.

  3. Measurement of composite shrinkage using a fibre optic Bragg grating sensor.

    Science.gov (United States)

    Milczewski, M S; Silva, J C C; Paterno, A S; Kuller, F; Kalinowski, H J

    2007-01-01

    Fibre Bragg grating is used to determine resin-based composite shrinkage. Two composite resins (Freedom from SDI and Z100 from 3M) were tested to determine the polymerization contraction behaviour. Each sample of resin was prepared with an embedded fibre Bragg grating. A LED activation unit with wavelength from 430 nm to 470 nm (Dabi Atlante) was used for resin polymerization. The wavelength position of the peak in the optical reflection spectra of the sensor was measured. The wavelength shift was related to the shrinkage deformation of the samples. Temperature and strain evolution during the curing phase of the material was monitored. The shrinkage in the longitudinal direction was 0.15 +/- 0.02% for resin Z100 (3M) and 0.06+/-0.01% for Freedom (SDI); two-thirds of shrinkage occurred after the first 50 s of illumination.

  4. 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

  5. A low-cost portable fibre-optic spectrometer for atmospheric absorption studies

    Directory of Open Access Journals (Sweden)

    J. Bailey

    2013-01-01

    Full Text Available A compact and portable solar absorption spectrometer based on fibre-optic Fabry–Perot technology has been built and tested. The instrument weighs only 4.2 kg and operates from 5 W of power from internal batteries. It provides spectroscopy over the range from 5980–6580 cm−1 (1.52–1.67 μm at a resolution of 0.16 cm−1. The input to the spectrometer is via single-mode optical fibre from a solar tracking system. Spectral scanning is carried out with a piezoelectrically scanned fibre Fabry–Perot tunable filter. Software has been developed to calibrate the spectra in wavelength and relative flux. The signal to noise ratio in solar spectra is about 700 for a spectrum scanned at 200 milliseconds per spectral point. The techniques used should be capable of being adapted to a range of wavelengths and to higher or lower resolutions.

  6. 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

  7. A Compact Nanosecond-Pulse Shaping System Based on Pulse Stacking in Fibres

    Institute of Scientific and Technical Information of China (English)

    SUI Zhan; LIN Hong-Huan; WANG Jian-Jun; ZHAO Hong-Ming; LI Ming-Zhong; QIAN Lie-Jia; ZHU He-Yuan; FAN Dian-Yuan

    2006-01-01

    @@ We demonstrate a compact pulse shaping system based on temporal stacking of pulses in fibres, by which synchronized pulses of ultrashort and nanosecond lasers can be obtained. The system may generate shape-controllable pulses with a fast rise time and high-resolution within a time window of ~2.2 ns by adjusting variable optical attenuators in the 32 fibre channels independently. With the help of optical amplifiers, the system delivers mJ-level pulses with a signal-to-noise ratio of~35 dB.

  8. Space radiation effect on fibre optical gyroscope control circuit and compensation algorithm

    Institute of Scientific and Technical Information of China (English)

    Zhang Chun-Xi; Tian Hai-Ting; Li Min; Jin Jing; Song Ning-Fang

    2008-01-01

    The process of a γ-irradiation experiment of fibre optical gyroscope (FOG) control circuit was described,in which it is demonstrated that the FOG control circuit,except for D/A converter,could endure the dose of 10krad with the protection of cabin material.The distortion and drift in D/A converter due to radiation,which affect the performance of FOG seriously,was indicated based on the elemental analysis.Finally,a compensation network based on adaptive neuro-fuzzy inference system is proposed and its function is verified by simulation.

  9. Smart medical textiles with embedded optical fibre sensors for continuous monitoring of respiratory movements during MRI

    Science.gov (United States)

    Witt, J.; Narbonneau, F.; Schukar, M.; Krebber, K.; De Jonckheere, J.; Jeanne, M.; Kinet, D.; Paquet, B.; Depré, A.; D'Angelo, L. T.; Thiel, T.; Logier, R.

    2010-09-01

    We report on three respiration sensors based on pure optical technologies developed during the FP6 EU project OFSETH. The developed smart medical textiles can sense elongation up to 3%, while maintaining the stretching properties of the textile substrates for a good comfort of the patient. The sensors, based on silica and polymer fibre, are developed for monitoring of patients during MRI examination. The OFSETH harness allows a continuous measurement of respiration movements while all vitals organs are free for medical staff actions. The sensors were tested in MRI environment and on healthy adults.

  10. Get smart, go optical: example uses of optical fibre sensing technology for production optimisation and subsea asset monitoring

    Science.gov (United States)

    Staveley, Chris

    2014-06-01

    With the growth in deep-water oil and gas production, condition monitoring of high-value subsea assets to give early warning of developing problems is vital. Offshore operators can then transport and deploy spare parts before a failure occurs, so minimizing equipment down-time, and the significant costs associated with unscheduled maintenance. Results are presented from a suite of tests in which multiple elements of a subsea twin-screw pump and associated electric motor were monitored using a fibre optic sensing system based on fibre Bragg gratings (FBG) that simultaneously measured dynamic strain on the main rotor bearings, pressure and temperature of the lubricating oil, distributed temperature through the motor stator windings and vibration of the pump and motor housings.

  11. Thermal Properties of Loose Tube Secondary Coated Optical Fibres Experimentally Discussed by a Relative Light Pulse Delay Technique

    Science.gov (United States)

    1983-11-17

    mechanical stability of fibre optic cables for example, shrinkage of the extruded operating at varying ambient conditions, plastic tubes at elevated...heating process. Controlling the Fibre Excess Length In the design of fibre optic cables -- with respect to temperature characteri- stics, it should be

  12. Temperature monitoring using fibre optic sensors in a lead-bismuth eutectic cooled nuclear fuel assembly

    Energy Technology Data Exchange (ETDEWEB)

    De Pauw, B., E-mail: bdepauw@vub.ac.be [Vrije Universiteit Brussel (VUB), Brussels Photonics Team (B-Phot), Brussels (Belgium); Vrije Universiteit Brussel (VUB), Acoustics and Vibration Research Group (AVRG), Brussels (Belgium); Belgian Nuclear Research Centre, (SCK-CEN), Boeretang 200, Mol (Belgium); Lamberti, A.; Ertveldt, J.; Rezayat, A.; Vanlanduit, S. [Vrije Universiteit Brussel (VUB), Acoustics and Vibration Research Group (AVRG), Brussels (Belgium); Van Tichelen, K. [Belgian Nuclear Research Centre, (SCK-CEN), Boeretang 200, Mol (Belgium); Berghmans, F. [Vrije Universiteit Brussel (VUB), Brussels Photonics Team (B-Phot), Brussels (Belgium)

    2016-02-15

    Highlights: • We demonstrate the use of optical fibre sensors in lead-bismuth cooled installations. • In this first of a kind experiment, we focus on temperature measurements of fuel rods • We acquire the surface temperature with a resolution of 30 mK. • We asses the condition of the installation during different steps of the operation. - Abstract: In-core temperature measurements are crucial to assess the condition of nuclear reactor components. The sensors that measure temperature must respond adequately in order, for example, to actuate safety systems that will mitigate the consequences of an undesired temperature excursion and to prevent component failure. This issue is exacerbated in new reactor designs that use liquid metals, such as for example a molten lead-bismuth eutectic, as coolant. Unlike water cooled reactors that need to operate at high pressure to raise the boiling point of water, liquid metal cooled reactors can operate at high temperatures whilst keeping the pressure at lower levels. In this paper we demonstrate the use of optical fibre sensors to measure the temperature distribution in a lead-bismuth eutectic cooled installation and we derive functional input e.g. the temperature control system or other systems that rely on accurate temperature actuation. This first-of-a-kind experiment demonstrates the potential of optical fibre based instrumentation in these environments. We focus on measuring the surface temperature of the individual fuel rods in the fuel assembly, but the technique can also be applied to other components or sections of the installation. We show that these surface temperatures can be experimentally measured with limited intervention on the fuel pin owing to the small geometry and fundamental properties of the optical fibres. The unique properties of the fibre sensors allowed acquiring the surface temperatures with a resolution of 30 mK. With these sensors, we assess the condition of the test section containing the fuel

  13. 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...

  14. Development and application of optical fibre strain and pressure sensors for in-flight measurements

    Science.gov (United States)

    Lawson, N. J.; Correia, R.; James, S. W.; Partridge, M.; Staines, S. E.; Gautrey, J. E.; Garry, K. P.; Holt, J. C.; Tatam, R. P.

    2016-10-01

    Fibre optic based sensors are becoming increasingly viable as replacements for traditional flight test sensors. Here we present laboratory, wind tunnel and flight test results of fibre Bragg gratings (FBG) used to measure surface strain and an extrinsic fibre Fabry-Perot interferometric (EFFPI) sensor used to measure unsteady pressure. The calibrated full scale resolution and bandwidth of the FBG and EFFPI sensors were shown to be 0.29% at 2.5 kHz up to 600 μɛ and 0.15% at up to 10 kHz respectively up to 400 Pa. The wind tunnel tests, completed on a 30% scale model, allowed the EFFPI sensor to be developed before incorporation with the FBG system into a Bulldog aerobatic light aircraft. The aircraft was modified and certified based on Certification Standards 23 (CS-23) and flight tested with steady and dynamic manoeuvres. Aerobatic dynamic manoeuvres were performed in flight including a spin over a g-range  -1g to  +4g and demonstrated both the FBG and the EFFPI instruments to have sufficient resolution to analyse the wing strain and fuselage unsteady pressure characteristics. The steady manoeuvres from the EFFPI sensor matched the wind tunnel data to within experimental error while comparisons of the flight test and wind tunnel EFFPI results with a Kulite pressure sensor showed significant discrepancies between the two sets of data, greater than experimental error. This issue is discussed further in the paper.

  15. Improving performance of optical fibre chaotic communication by dispersion compensation techniques

    Institute of Scientific and Technical Information of China (English)

    Zhang Jian-Zhong; Wang Yun-Cai; Wang An-Bang

    2008-01-01

    This paper numerically investigates the effects of dispersion on optical fibre chaotic communication,and proposes a dispersion compensation scheme to improve the performance of optical fibre chaotic communication system.The obtained results show that the transmitter-receiver synchronization progressively degrades and the signal-to-noise ratio of the recovered message deteriorates as the fibre length increases due to the dispersion accumulation.Two segments of 2.5-km dispersion-compensating fibres are symmetrically placed at both ends of a segment of 245-km nonzero dispersionshifted fibre with low dispersion in one compensation period.The numerical results show that the signal-to-noise ratio of the extracted 1 GHz sinusoidal message is improved from-2.92 dB to 15.38 dB by this dispemion compensation for the transmission distance of 500 km.

  16. Spatial Kerr solitons in optical fibres of finite size cross section: beyond the Townes soliton

    Science.gov (United States)

    Drouart, F.; Renversez, G.; Nicolet, A.; Geuzaine, C.

    2008-12-01

    We propose a new and efficient numerical method to find spatial solitons in optical fibres with a nonlinear Kerr effect including microstructured ones. A nonlinear non-paraxial scalar model of the electric field in the fibre is used (nonlinear Helmholtz equation) and an iterative algorithm is proposed to obtain the nonlinear solutions using the finite element method. The field is supposed to be harmonic in time and along the direction of invariance of the fibre but inhomogeneous in the cross section. In our approach, we solve a nonlinear eigenvalue problem in which the propagation constant is the eigenvalue. Several examples dealing with step-index fibres and microstructured optical fibres with a finite size cross section are described. In each geometry, a single self-coherent nonlinear solution is obtained. This solution, which also depends on the size of the structure, is different from the Townes soliton—but converges towards it at small wavelengths.

  17. 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.

  18. 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...

  19. 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.

  20. Power transmission coefficients for multi-step index optical fibres.

    Science.gov (United States)

    Aldabaldetreku, Gotzon; Zubia, Joseba; Durana, Gaizka; Arrue, Jon

    2006-02-20

    The aim of the present paper is to provide a single analytical expression of the power transmission coefficient for leaky rays in multi-step index (MSI) fibres. This expression is valid for all tunnelling and refracting rays and allows us to evaluate numerically the power attenuation along an MSI fibre of an arbitrary number of layers. We validate our analysis by comparing the results obtained for limit cases of MSI fibres with those corresponding to step-index (SI) and graded-index (GI) fibres. We also make a similar comparison between this theoretical expression and the use of the WKB solutions of the scalar wave equation.

  1. 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...

  2. Rare-Earth Doped Photonic Crystal Fibre Lasers and Amplifiers

    DEFF Research Database (Denmark)

    Hougaard, Kristian G.

    2005-01-01

    In this thesis, a theoretical and numerical study of the use of rare-earthdoped photonic crystal fibres as optical amplifiers and lasers, has been performed. Photonic crystal fibres or microstructured optical fibres is a new kind of optical fibre in which the cladding region typically consist...... of a periodic microstructure, resulting in a fibre with very different properties compared to conventional optical fibres. The properties of photonic crystals fibres are described, with focus on the advantages this technology provides compared to conventional fibres, within the area of optical amplification....... The thesis also presents the basic properties of optical amplification, and describes the numerical model developed to model the behaviour of lasers and amplifiers based on photonic crystal fibres. The developed numerical tools are then used to investigate specific applications of photonic crystal fibres...

  3. 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...

  4. 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

  5. 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.

  6. Coupling light into optical fibres near the diffraction limit

    CERN Document Server

    Horton, A J; Horton, Anthony J.; Bland-Hawthorn, Joss

    2006-01-01

    The burgeoning field of astrophotonics explores the interface between astronomy and photonics. Important applications include photonic OH suppression at near-infrared wavelengths, and integrated photonic spectroscopy. These new photonic mechanisms are not well matched to conventional multi-mode fibres and are best fed with single or few-mode fibres. We envisage the largest gains in astrophotonics will come from instruments that operate with single or few-mode fibres in the diffraction limited or near diffraction limited regimes. While astronomical instruments have largely solved the problem of coupling light into multi-mode fibres this is largely unexplored territory for few-mode and single-mode fibres. Here we describe a project to explore this topic in detail, and present initial results on coupling light into single and few-mode fibres at the diffraction limit. We find that fibres with as few as ~5 guided modes have qualitatively different behaviour to single-mode fibres and share a number of the beneficia...

  7. A composite fibre optic catheter for monitoring peristaltic transit of an intra-luminal bead.

    Science.gov (United States)

    Arkwright, John W; Underhill, Ian D; Dodds, Kelsi N; Brookes, Simon J H; Costa, Marcello; Spencer, Nick J; Dinning, Phil G

    2016-03-01

    A fibre optic motion sensor has been developed for monitoring the proximity and direction of motion of a ferrous bead travelling axial to the sensor. By integrating an array of these sensors into our previously developed fibre optic manometry catheters we demonstrate simultaneous detection of peristaltic muscular activity and the associated motion of ferrous beads through a colonic lumen. This allows the motion of solid content to be temporally and spatially related to pressure variations generated by peristaltic contractions without resorting to videoflouroscopy to track the motion of a radio opaque bolus. The composite catheter has been tested in an in-vitro animal preparation consisting of excised sections of rabbit colon. Cut-away image of the fibre optic motion sensor showing the location of the fibre Bragg gratings and the rare earth magnet.

  8. Optical fibre long period grating spectral actuators utilizing ferrofluids as outclading overlayers

    Science.gov (United States)

    Konstantaki, M.; Candiani, A.; Pissadakis, S.

    2011-03-01

    Results are presented on the spectral tuning of optical fibre long period gratings utilizing water and oil based ferrofluids as outclading overlayers, under static magnetic field stimulus. Two approaches are adopted for modifying the ambient refractive index at the position of the long period grating. In the first approach, a water based ferrofluid is controllably translated along the length of the grating via a magnetic field. Changes as high as 7.5nm and 6.5dB are monitored in the wavelength and strength, respectively, of the attenuation bands of the grating. The repeatable performance of this device for repetitive forward and backward translation verifies that no ferrofluidic residue is left on the fibre, due to silanization cladding functionalisation. In the second approach, the refractive index of an oil based ferrofluidic overlayer is modified through the magneto-optical effect. For an applied static magnetic field in the order of 400 Gauss the strength of the attenuation band of the grating is modified by more than 10% while its spectral position remains unaffected. Accordingly for the implementation of the last approach, the magnetically induced refractive index changes of ferrofluids of different solution concentrations are studied by employing diffraction efficiency measurements.

  9. Measurement of sound field in cavitating media by an optical fibre-tip hydrophone.

    Science.gov (United States)

    Koch, Christian; Jenderka, Klaus-Vitold

    2008-04-01

    A fibre-optic technique was applied to measure the sound field in an ultrasonic cleaning vessel under practical conditions. A metal-coated fibre-tip is used as a sensor and a heterodyne interferometer detects the change in the optical path resulting from the movement of the fibre-tip in the sound field. Spectrally resolved sound field parameters such as the fundamental, the subharmonic or cavitation noise are extracted from the measurements and compared with results obtained by a piezo-electric hydrophone. It was found that the fibre sensor provides a signal related to the velocity in the sound field, but the information about cavitation-related parameters is similar to the information for pressure sensing techniques. The fibre-optic sensors have a uniquely high spatial resolution and the sound detection process is strongly influenced by single cavitation events close to the small fibre-tip. This paper shows that fibre-tip sensors are an alternative to common hydrophone techniques. They can open up new possibilities for measurement problems for which so far no solution exists, in particular when a high spatial resolution is required or when the measurement site is small.

  10. Optimised design of fibre-based pulse compressor for gain-switched DFB laser pulses at 1.5 µm

    OpenAIRE

    Barry, Liam P.; Thomsen, Benn C.; Dudley, John M.; Harvey, John D.

    1999-01-01

    An optical-fibre based pulse compressor for gain-switched DFB laser pulses has been optimised using a systematic procedure based on the initial complete characterisation of the laser pulses, followed by numerical simulations of the pulse propagation in different types of fibre to determine the required lengths for optimum compression. Using both linear and nonlinear compression techniques, an optimum compression factor of 12 is achieved.

  11. Fabrication of integrated optic fibre tip for micron CMMs touch trigger probe application

    Science.gov (United States)

    Ji, H.; Hsu, H. Y.; Chua, J.; Kong, L. X.; Wedding, A. B.; She, M.; Lin, G. C. I.; Fan, K. C.

    2005-12-01

    In the last decade the general miniaturisation of complex products has lead to an increased importance of high precision machining and assembly. Together with increasing precision of products, the need for highly accurate dimensional inspection increases. CMMs (Coordinate Measuring Machines), as a versatile and widespread dimensional metrology tool, can efficiently perform complex measurement with a resolution of about 0.1μm and a repeatability of about 0.3μm. The existing probes for CMMs tend to be very bulky and result in high probing forces for geometrical measurements of high accuracy on small parts. In this paper, an economical flexible method, which is based on optical fibre splicer, is proposed to fabricate an integrated micro scale silicon probe with spherical tip for micron CMMs. Based on Taguchi method, a combination of optimised process parameters has been obtained to control the fabrication conditions that will ensure the manufacturing of tips of a high and consistent quality. With proper control of the process parameters, an optic fibre probe tip with the diameter dimension in the range of 200 to 400μm is achieved and there is a great potential to fabricate a smaller tip with a diameter of 50-100μm in the future.

  12. 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.

  13. Zero Dispersion Optical Fibres for High Data Rate Systems

    Directory of Open Access Journals (Sweden)

    V. V. Rampal

    1981-07-01

    Full Text Available The different dispersion parameters that contribute to the pulse spreading in a single mode fibre are discussed with particular reference to the possibility of reducing the total dispersion to zero and increasing the bandwidth and repeater spacing.

  14. Integration of conductive reduced graphene oxide into microstructured optical fibres for optoelectronics applications.

    Science.gov (United States)

    Ruan, Yinlan; Ding, Liyun; Duan, Jingjing; Ebendorff-Heidepriem, Heike; Monro, Tanya M

    2016-02-22

    Integration of conductive materials into optical fibres can largely expand functions of fibre devices including surface plasmon resonator/metamaterial, modulators/detectors, or biosensors. Some early attempts have been made to incorporate metals such as tin into fibres during the fibre drawing process. Due to the restricted range of materials that have compatible melting temperatures with that of silica glass, the methods to incorporate metals along the length of the fibres are very challenging. Moreover, metals are nontransparent with strong light absorption, which causes high fibre loss. This article demonstrates a novel but simple method for creating transparent conductive reduced graphene oxide film onto microstructured silica fibres for potential optoelectronic applications. The strongly confined evanescent field of the suspended core fibres with only 2 μW average power was creatively used to transform graphene oxide into reduced graphene oxide with negligible additional loss. Existence of reduced graphene oxide was confirmed by their characteristic Raman signals, shifting of their fluorescence peaks as well as largely decreased resistance of the bulk GO film after laser beam exposure.

  15. Thermal characterization of Bragg gratings in polarization-maintaining optical fibres: analysis of birefringence and regeneration

    Science.gov (United States)

    Abe, I.; de Oliveira, V.; Fiorin, R.; Kalinowski, H. J.

    2017-04-01

    This paper presents an analysis of birefringence and regeneration of fibre Bragg gratings (FBGs) in two types of polarization-maintaining (PM) optical fibres, bow tie and internal elliptical cladding (IEC), with different diameters. The thermal regeneration of FBGs in PM fibres with different degrees of saturation (weakly, slightly, and strongly saturated) is presented and the influence of the gratings’ saturation degree on the birefringence of PM fibres is shown. The birefringence values obtained for IEC fibres with 80 µm of diameter were for a strongly saturated seed grating of 5.3  ×  10‑4 and 6.2  ×  10‑4 refractive index units after the regeneration. The evolution of the fibre birefringence as a function of the temperature is presented and the results show hysteresis and nonlinear dependence of the birefringence on temperature. The thermal stability of regenerated gratings in PM fibres is demonstrated, and a sensitivity coefficient value of 0.0035 dBm min‑1 at 900 °C was obtained. The results obtained show the feasibility of optimization of fibre birefringence; this could allow such fibers to be used as temperature sensors and even improve the birefringence after the grating regeneration.

  16. Efficient optical pumping and high optical depth in a hollow-core photonic-crystal fibre for a broadband quantum memory

    CERN Document Server

    Sprague, Michael R; Abdolvand, Amir; Nunn, Joshua; Jin, Xian-Min; Kolthammer, W Steven; Barbieri, Marco; Rigal, Bruno; Michelberger, Patrick S; Champion, Tessa F M; Russell, Philip St J; Walmsley, Ian A

    2012-01-01

    The generation of large multiphoton quantum states - for applications in computing, metrology, and simulation - requires a network of high-efficiency quantum memories capable of storing broadband pulses. Integrating these memories into a fibre offers a number of advantages towards realising this goal: strong light-matter coupling at low powers, simplified alignment, and compatibility with existing photonic architectures. Here, we introduce a large-core kagome-structured hollow-core fibre as a suitable platform for an integrated fibre-based quantum memory with a warm atomic vapour. We demonstrate, for the first time, efficient optical pumping in a hollow-core photonic-crystal fibre with a warm atomic vapour, where (90 $\\pm$ 1)% of atoms are prepared in the ground state. We measure high optical depths (3$\\times 10^{4}$) and, also, narrow homogeneous linewidths that do not exhibit significant transit-time broadening. Our results establish that kagome fibres are suitable for implementing a broadband, room-tempera...

  17. FOSREM - Fibre-Optic System for Rotational Events&Phenomena Monitoring

    Science.gov (United States)

    Jaroszewicz, Leszek; Krajewski, Zbigniew; Kurzych, Anna; Kowalski, Jerzy; Teisseyre, Krzysztof

    2016-04-01

    We present the construction and tests of fiber-optic rotational seismometer named FOSREM (Fibre-Optic System for Rotational Events&Phenomena Monitoring). This presented device is designed for detection and monitoring the one-axis rotational motions, brought about to ground or human-made structures both by seismic events and the creep processes. The presented system works by measuring Sagnac effect and generally consists of two basic elements: optical sensor and electronic part. The optical sensor is based on so-called the minimum configuration of FOG (Fibre-Optic Gyroscope) where the Sagnac effect produces a phase shift between two counter-propagating light beams proportional to the measured rotation speed. The main advantage of the sensor of this type is its complete insensitivity to linear motions and a direct measurement of rotational speed. It may work even when tilted, moreover, used in continuous mode it may record the tilt. The electronic system, involving specific electronic solutions, calculates and records rotational events data by realizing synchronous in a digital form by using 32 bit DSP (Digital Signal Processing). Storage data and system control are realised over the internet by using connection between FOSREM and GSM/GPS. The most significant attribute of our system is possibility to measure rotation in wide range both amplitude up to 10 rad/s and frequency up to 328.12 Hz. Application of the wideband, low coherence and high power superluminescent diode with long fibre loop and suitable low losses optical elements assures the theoretical sensitivity of the system equal to 2·10-8 rad/s/Sqrt(Hz). Moreover, the FOSREM is fully remote controlled as well as is suited for continuous, autonomous work in very long period of time (weeks, months, even years), so it is useful for systematic seismological investigation at any place. Possible applications of this system include seismic monitoring in observatories, buildings, mines and even on glaciers and in

  18. 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.

  19. Carbon nanotubes for ultrafast fibre lasers

    Science.gov (United States)

    Chernysheva, Maria; Rozhin, Aleksey; Fedotov, Yuri; Mou, Chengbo; Arif, Raz; Kobtsev, Sergey M.; Dianov, Evgeny M.; Turitsyn, Sergei K.

    2017-01-01

    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.

  20. Spectroscopic signature of phosphate crystallization in Erbium-doped optical fibre preforms

    CERN Document Server

    Peretti, Romain; Jacquier, Bernard; Blanc, Wilfried; Dussardier, Bernard; 10.1016/j.optmat.2011.01.005

    2011-01-01

    In rare-earth-doped silica optical fibres, the homogeneous distribution of amplifying ions and part of their spectroscopic properties are usually improved by adding selected elements, such as phosphorus or aluminum, as structural modifier. In erbium ion (Er3+) doped fibres, phosphorus preferentially coordinates to Er3+ ions to form regular cages around it. However, the crystalline structures described in literature never gave particular spectroscopic signature. In this article, we report emission and excitation spectra of Er3+ in a transparent phosphorus-doped silica fibre preform. The observed line features observed at room and low temperature are attributed to ErPO4 crystallites.

  1. Application of Fiber Optic Instrumentation (Validation des systemes d’instrumentation a fibres optiques)

    Science.gov (United States)

    2012-07-01

    grandeur et les progrès réalisés en termes de faisabilité de capteurs continus sont rapides. Les systèmes à fibres optiques vont révolutionner...fibres optiques ) This AGARDograph has been sponsored by SCI-228, the Flight Test Technology Task Group of the Systems Concepts and Integration...Series – Volume 22 SCI-228 Application of Fiber Optic Instrumentation (Validation des systèmes d’instrumentation à fibres optiques ) This

  2. 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 presen...... and a simplification of the detection regime for an optimal interferometric OAE configuration. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only....

  3. Fibre-optic photochemical stroke: generating and measuring photochemical changes inside the brain

    Science.gov (United States)

    Tsiminis, G.; Klarić, T. S.; Schartner, E. P.; Warren-Smith, S. C.; Lewis, M. D.; Koblar, S. A.; Monro, T. M.

    2014-05-01

    We report here on the development of a method to induce a stroke in a specific location within a mouse brain through the use of an optical fibre. By capturing the emitted fluorescence signal generated using the same fibre it is then possible to monitor photochemical changes within the brain in real-time, potentially reducing the requirement for post-operative histology to determine if a stroke has successfully been induced within the animal.

  4. 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.

  5. Improved fibre optic acoustic sensors for partial discharge in elastomeric insulations

    Science.gov (United States)

    Rohwetter, Philipp; Lothongkam, Chaiyaporn; Habel, Wolfgang; Heidmann, Gerd; Pepper, Daniel

    2014-05-01

    Partial discharge in elastomeric high voltage insulations is a major reason for device failure. The special challenges of the high voltage environment limit the use of conventional acoustic emission sensors. Fibre-optic sensors can cope with these challenges thanks to their optical sensing principle and the use of all-dielectric materials. In this contribution, improvements to a previously introduced design of ultrasonic fibre-optic acoustic partial discharge sensors for elastomeric insulations are presented. The improved performance of fibre-optic acoustic sensors in detecting AC partial discharge is demonstrated. Furthermore, their ability to detect low-level damage processes in elastomeric insulation under DC dielectric stress is shown to outperform the highly sensitive electrical detection method.

  6. 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.

    2016-03-01

    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 (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.

  7. Shape memory polymeric composites sensing by optic fibre Bragg gratings: A very first approach

    Science.gov (United States)

    Quadrini, Fabrizio; Santo, Loredana; Ciminello, Monica; Concilio, Antonio; Volponi, Ruggero; Spena, Paola

    2016-05-01

    Shape memory polymer composites (SMPCs) have the potential for many applications in aerospace, spanning from self-repairing of structures to self-deploying of antennas, solar sails, or functional devices (e.g. for grabbing small space debris). In all these cases, it may be essential to have information about their configuration at different stages of shape recovery. In this study, the strain history of a prepreg carbon fibre system, cured with a shape memory polymer (SMP) interlayer, is monitored through a Fibre Bragg Grating (FBG), a fibre optic sensor device. SMPC has been manufactured by using traditional technologies for aerospace. After manufacturing cylindrical shape samples, an external fibre optic system is added to the composite structure; this system is especially suited for high temperatures which are necessary for SMP recovery and composite softening. Sensor functionality is checked before and after each strain history path. Optic fibre arrangement is optimized to avoid unwanted breakings whereas strains are limited by fibre collapsing, i.e. within nominal 2% of deformation. Dynamic information about shape recovery gives fundamental insights about strain evolution during time as well as its spatial distribution.

  8. All-fibre micro-ring resonator based on tapered microfibre

    Institute of Scientific and Technical Information of China (English)

    Dong Xiao-Wei; Lu Shao-Hua; Feng Su-Chun; Xu Ou; Jian Shui-Sheng

    2008-01-01

    In this paper, bendloss characteristics of an optical fibre are investigated in detail, and the results show that the resonator with a smaller ring radius, wider free spectrum range (FSR), higher fineness (f) and quality-factor (Q) can be achieved by using microfibres. Based on the improved fused taper technique, a high-quality microfibre with 5 μm radius has been fabricated, and an all-fibre micro-ring resonator with a radius of only 500 μm is realized using self-coiling coupling method. The good-resonant characteristic makes the all-fibre device be expected to avoid bendloss and connection loss associated with planar waveguide integration.

  9. A Review of Refractometric Sensors Based on Long Period Fibre Gratings

    Directory of Open Access Journals (Sweden)

    G. Rego

    2013-01-01

    Full Text Available In the last decade refractometric sensors have attracted an increasing interest by the scientific community due to their ability to perform ambient monitoring, to assess food quality and safety, and also to the fact that they enable the development of label free sensors in the biomedical area. These advances result, namely, from the use of long period fibre gratings in the turning points and/or with thin films in the transition region that allows resolutions of 10−6 to changes in the refractive index of the surrounding medium. Resolutions exceeding 10−8 can also be achieved when long period fibre gratings are combined with evanescent field based devices. This paper reviews the recent path towards the development of ultrahigh sensitive optical fibre refractometric sensors.

  10. A review of refractometric sensors based on long period fibre gratings.

    Science.gov (United States)

    Rego, G

    2013-01-01

    In the last decade refractometric sensors have attracted an increasing interest by the scientific community due to their ability to perform ambient monitoring, to assess food quality and safety, and also to the fact that they enable the development of label free sensors in the biomedical area. These advances result, namely, from the use of long period fibre gratings in the turning points and/or with thin films in the transition region that allows resolutions of 10(-6) to changes in the refractive index of the surrounding medium. Resolutions exceeding 10(-8) can also be achieved when long period fibre gratings are combined with evanescent field based devices. This paper reviews the recent path towards the development of ultrahigh sensitive optical fibre refractometric sensors.

  11. 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.

  12. Efficient optical pumping and high optical depth in a hollow-core photonic-crystal fibre for a broadband quantum memory

    Science.gov (United States)

    Sprague, Michael R.; England, Duncan G.; Abdolvand, Amir; Nunn, Joshua; Jin, Xian-Min; Kolthammer, W. Steven; Barbieri, Marco; Rigal, Bruno; Michelberger, Patrick S.; Champion, Tessa F. M.; Russell, Philip St. J.; Walmsley, Ian A.

    2013-05-01

    The generation of large multiphoton quantum states—for applications in computing, metrology and simulation—requires a network of high-efficiency quantum memories capable of storing broadband pulses. Integrating these memories into a fibre offers a number of advantages towards realizing this goal: strong light-matter coupling at low powers, simplified alignment and compatibility with existing photonic architectures. Here, we introduce a large-core kagome-structured hollow-core fibre as a suitable platform for an integrated fibre-based quantum memory with a warm atomic vapour. We demonstrate, for the first time, efficient optical pumping in such a system, where 90 ± 1% of atoms are prepared in the ground state. We measure high optical depths (3 × 104) and narrow homogeneous linewidths (6 ± 2 MHz) that do not exhibit significant transit-time broadening, showing that we can prepare a Λ-level system in a pure state. Our results establish that kagome fibres are suitable for implementing a broadband, room-temperature quantum memory, as well as a range of nonlinear optical effects.

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

    DEFF Research Database (Denmark)

    Peucheret, Christophe

    2003-01-01

    measurement techniques are first reviewed, and the limitations of the commonly used phase-shift technique is discussed. Additionally, an alternative method which enables the direct determination of small dispersion values in the pass-band of optical filters is proposed. Available optical filter technologies...... km pre-compensated spans. Passive pre distortion at the transmitter is shown to significantly improve the reach of the systems. Based on the experimental results, transparent domains with a diameter of the order of 1000 km can be realised, thus demonstrating the applicability of the optimisation...

  14. 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.

  15. A Tuning Fork with a Short Fibre Probe Sensor for a Near-FieldScanning Optical Microscope

    Institute of Scientific and Technical Information of China (English)

    王沛; 鲁拥华; 章江英; 明海; 谢建平; 黄建文; 高宗圣; 蔡定平

    2002-01-01

    We report on a tapping-mode tuning fork with a short fibre probe sensor for a near-field scanning optical microscope. The method demonstrates how to fabricate the short fibre probe. This tapping-mode tuning fork with a short fibre probe can provide stable and high Q at the tapping frequency of the tuning fork, and can give high-quality near-field scanning optical microscope and atomic force microscope images of samples. We present the results of using the tapping-mode tuning fork with a short fibre probe sensor for a near-field scanning optical microscope performed on an eight-channel silica waveguide.

  16. Fabrication and Sensing Performance of Smart Composite Structures Using Optical Fibre Sensors

    Institute of Scientific and Technical Information of China (English)

    C Y Wei; S W James; C C Ye; R P Tatam; P E lrving

    2000-01-01

    This paper determines the performance of Fibre Bragg Grating (FBG) sensors for strain sensing applications in carbon fibre composite materials. Carbon fibre laminates in either cross-plied or quasiisotropic stacking sequences were fabricated using T300/Hexcel 914 prepregs. The FBG optical sensors were either surface attached, or embedded within laminates. The sensor orientation was aligned either parallel or transverse to the adjacent carbon fibre layers. The composite structures with integrated FBG sensors were subjected to static tensile loading. A scanning fibre Fabry-Perot filter was used to monitor the reflected Bragg wavelengths. The optical sensor embedded between two 90° carbon fibre plies shows a high sensitivity to multi-site cracking formed in the transverse plies. The embedding in 90° plies seems to change the local stress distributions and to become a source of crack initiation. Efficient stress transfer from the host materials to the sensors is dependent upon incorporation methods, the thickness of the adhesive layers, and the location of the sensors.

  17. 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.

  18. 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.

  19. Flavin and porphyrin-micro optical fibre biosensor: analysis and design

    Science.gov (United States)

    Velazquez-Gonzalez, J. S.; Mujica-Ascencio, S.; Aguilar Morales, A. I.; Marrujo-Garcia, S.; Alvarez-Chavez, J. A.; Martinez-Pinon, F.

    2014-05-01

    Micro Optical Fibre Biosensors (MOFBs) are emerging as one of the most sensitive bio-detection system technologies which do not require of labelling or amplification of the analyte. In these devices, a short region of the fibre core is exposed to the external environment so that the evanescent field can interact with biological species such as cells, proteins, and DNA. In order to increase the sensitivity and selectivity, MOFBs are often used in combination with other optical transduction mechanisms such as changes in refractive index, absorption, fluorescence and surface plasmon resonance. In this work we present the full characteristics, analysis and design of a MOFBs for Flavin and Porphyrin detection.

  20. Forty-Four Pass Fibre Optic Loop for Improving the Sensitivity of Surface Plasmon Resonance Sensors

    CERN Document Server

    Su, Chin B

    2007-01-01

    A forty-four pass fibre optic surface plasmon resonance sensor that enhances detection sensitivity according to the number of passes is demonstrated for the first time. The technique employs a fibre optic recirculation loop that passes the detection spot forty- four times, thus enhancing sensitivity by a factor of forty-four. Presently, the total number of passes is limited by the onset of lasing action of the recirculation loop. This technique offers a significant sensitivity improvement for various types of plasmon resonance sensors that may be used in chemical and biomolecule detections.

  1. 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.

  2. The duration of fibre-optic intubation is increased by cricoid pressure. A randomised double-blind study

    DEFF Research Database (Denmark)

    Arenkiel, Bjørn; Smitt, M; Olsen, K S

    2013-01-01

    In some categories of patients, a rapid sequence induction using a fibre-optic method may be indicated. The aim of the present study was to examine the effect of cricoid pressure (CP) on the duration of fibre-optic intubation. The hypothesis was that CP would prolong the intubation time....

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

    DEFF Research Database (Denmark)

    Aslan, Mustafa

    that currently have the largest market share for composite applications. However, the most critical limitation in the use of cellulosic fibre composites for structural applications is the lack of well described fibre properties, in particular, the tensile strength. This is due to variations in fibre morphology...... of the internal cell wall structures. This is in contrast to the crack growth in brittle ceramic and glass fibres. Moreover, two typical stress-strain curves (linear and non-linear) measured for the flax fibres were found to be correlated with the amount of defected region in the fibres. The defects are induced...... a similar microstructure at low fibre weight fractions. However, when the fibre content is increased, a difference in porosity content can be observed from the composite cross sections. The nominal tensile strength of the unidirectional flax fibre/LPET composites is measured in the range 180 to 340 MPa...

  4. Fibre optic Bragg grating sensors: an alternative method to strain gauges for measuring deformation in bone.

    Science.gov (United States)

    Fresvig, T; Ludvigsen, P; Steen, H; Reikerås, O

    2008-01-01

    Strain gauges are currently the default method for measuring deformation in bone. Strain gauges are not well suited for in vivo measurements because of their size and because they are difficult to use in bone. They are also unsuitable for repeated measurements over time since they cannot be left in the patient. The optical Bragg grating fibres behave like selective filters of light. As a result the structure will transmit most wavelengths of light, but will reflect certain specific wavelengths. If the Bragg grating is strained along the fibre axis, the wavelength will shift, and this change represents a measure of strain. The optical fibres are very thin, no thicker than a standard surgical suture and are easy to adhere to bone by use of the FDA approved polymethyl-methacrylate (PMMA) as bonding adhesive. Since they are made of biocompatible silica porous bioglass ceramics, it should also be possible to leave the fibres in the patient between and after measurements. We have shown that fibre optic Bragg grating sensors can be used as a measurement tool for bone strain by performing measurements both on an acryl tube and on an extracted sample of human femur diaphysis. On either of them we used four fibre optic sensors and four strain gauges, interspersed at every 45 degrees around the circumference. The standard deviation of the measurements on the acrylic tube for each of the sensors, both optical fibres and strain gauges, varied from 1.0 to 5.2%. Every sensor, both optical fibre and strain gauge, correlated significantly with all of the rest at the 0.01 level with a Pearson correlation coefficient r ranging from 0.986 to 1.0. The linearity for all of the sensors versus load was excellent, the lowest linearity of the eight sensors was 0.996 as expressed by r(2) (coefficient of determination), with no significant difference in linearity between optical fibres and strain gauges. Bone is not an ideal isotropic material, and we found that the strain readings of the

  5. Measurement of stress-strain behaviour of human hair fibres using optical techniques.

    Science.gov (United States)

    Lee, J; Kwon, H J

    2013-06-01

    Many studies have presented stress-strain relationship of human hair, but most of them have been based on an engineering stress-strain curve, which is not a true representation of stress-strain behaviour. In this study, a more accurate 'true' stress-strain curve of human hair was determined by applying optical techniques to the images of the hair deformed under tension. This was achieved by applying digital image cross-correlation (DIC) to 10× magnified images of hair fibres taken under increasing tension to estimate the strain increments. True strain was calculated by summation of the strain increments according to the theoretical definition of 'true' strain. The variation in diameter with the increase in longitudinal elongation was also measured from the 40× magnified images to estimate the Poisson's ratio and true stress. By combining the true strain and the true stress, a true stress-strain curve could be determined, which demonstrated much higher stress values than the conventional engineering stress-strain curve at the same degree of deformation. Four regions were identified in the true stress-strain relationship and empirical constitutive equations were proposed for each region. Theoretical analysis on the necking condition using the constitutive equations provided the insight into the failure mechanism of human hair. This analysis indicated that local thinning caused by necking does not occur in the hair fibres, but, rather, relatively uniform deformation takes place until final failure (fracture) eventually occurs.

  6. Optical fibre pressure and temperature sensor system designed for urodynamic applications

    Science.gov (United States)

    Duraibabu, Dineshbabu; Kelly, Niall; Poeggel, Sven; Flood, Hugh; Yuan, Hongwei; Dooly, Gerard; McGrath, Deirdre; Tosi, Daniele; Lewis, Elfed; Leen, Gabriel

    2016-05-01

    This paper presents an optical fibre pressure and temperature sensor (OFPTS) system, which is adapted for use as a urodynamic pressure measurement system (UPS) for differential pressure measurement with temperature compensation. The OFTPS is based on a Fabry Perot interferometer (FPI), which acts as a pressure sensor and includes an embedded fibre Bragg grating (FBG) for temperature measurement. The sensor system is evaluated in a lower urinary tract (LUT) simulator, which simulates the bladder, rectum and detrusor muscle. The system was benchmarked against a commercially available urodynamic system, at the University Hospital Limerick (UHL) Urology Clinic. Both systems demonstrate a high correlation with a relative pressure variation of less than +/-2.8cmH2O for abdominal and +/-4cmH2O for vesical pressure. The repetitive measurement of the OFPTS system in the LUT simulator against the commercial system demonstrated the high repeatability. Furthermore, the low fabrication cost makes the OFPTS a potentially interesting instrument for urodynamic and other medical applications.

  7. Preliminary evaluation of a new fibre-optic cerebral oximetry system.

    Science.gov (United States)

    Phillips, J P; Langford, R M; Kyriacou, P A; Jones, D P

    2008-12-01

    A new system for measuring the oxygen saturation of blood within tissue has been developed, for a variety of patient monitoring applications. A particular unmet need is in the central nervous system, and this project aims to devise a means for measuring blood oxygen saturation in the brain tissue of patients recovering from neurosurgery or head injury. Coupling light sources and a photodetector to optical fibres results in a probe small enough to pass through a cranial bolt of the type already in use for intra-cranial pressure monitoring. The development and evaluation of a two-wavelength fibre-optic reflectance photoplethysmography (PPG) system are described. It was found that good quality red and near-infrared PPG signals could be obtained from the finger using a fibre-optic probe. Experiments were conducted to find the inter-fibre spacings that yield signals most suitable for calculating oxygen saturation. Reliable signals could be obtained for inter-fibre spacings between 2 mm and 5 mm, the latter being the size of the maximum aperture in the cranial bolt. A preliminary measurement from human brain tissue is also presented.

  8. Optical transmission of PMMA optical fibres exposed to high intensity UVA and visible blue light

    Science.gov (United States)

    Alobaidani, A. D.; Furniss, D.; Johnson, M. S.; Endruweit, A.; Seddon, A. B.

    2010-05-01

    Optical transmission of PMMA (polymethylmethacrylate) POF (polymer optical fibre) in the spectral range from 280 to 450 nm is investigated with a high radiation emission source comprising a mercury lamp delivering 40 W/cm 2 at the PMMA POF launch face. The heat generated from the radiation source causes a sudden drop in the launched radiation due to thermal-oxidation and photo-degradation of the launch face of the PMMA POF; this results in a loss of 53% of the total launched power within 13 min of exposure to the source. The thermal-oxidation degradation is controlled by a cooling device which improves the transmission stability of the fibre. However, photo-degradation is still active and causes a loss in power of 7% in 13 min. The spectral output of the transmitted radiation through the PMMA POF was monitored and indicates the variation in optical loss with wavelength. High rates of nominal absorption for the irradiated PMMA POF are found below 320 nm wavelength. From the Beer-Lambert law, the photo-degradation effect with time of a fixed path length of PMMA POF is described by the absorption coefficient ( αλ, cm -1) . The nominal absorption coefficient αλ values in the range 335-368 nm wavelength are found to be higher after 1 h of irradiation than the values in the range 406-438 nm. However, the relative change in the nominal absorption coefficient Δ αλ is greater at 438 nm than at 335 nm, 368 or 406 nm. After 1 h of irradiation with the cooling device in place, the PMMA POF transmission was reduced to 44.8% of its initial value; this recovered to a maximum of 86% of the original transmission of the total launched power after 5 weeks in ambient conditions.

  9. A Sagnac-Michelson fibre optic interferometer: Signal processing for disturbance localization

    Science.gov (United States)

    Kondrat, M.; Szustakowski, M.; Pałka, N.; Ciurapiński, W.; Życzkowski, M.

    2007-09-01

    We present numerical and experimental results on a new generation fibre optic perimeter sensor based on a Sagnac and Michelson interferometers configuration. In particular, an original signal processing scheme is presented. The sensor can detect a potential intruder and determine its position along a protected zone. We propose a localization method that offers the inherent properties of both interferometers. After demodulation of the signals from both interferometers, the obtained amplitude characteristic of the Sagnac interferometer depends on a position of a disturbance along the interferometer, while amplitude characteristic of the Michelson interferometer does not depend on this position. So, quotient of both demodulated characteristics makes it possible to localize the disturbance. During investigations of a laboratory model of the sensor, it was possible to detect the position of the disturbance with a resolution of about 40 m along the 6-km-long sensor.

  10. A tiled CCD detector with 2x2 array and tapered fibre optics for electron microscopy

    CERN Document Server

    Faruqi, A R; Cattermole, D M; Stubbings, S

    2002-01-01

    Charge coupled devices (CCD)-based detectors have made a major impact on data collection in electron microscopy over the past few years. There have been a number of successful applications of CCDs in electron crystallography of two-dimensional protein crystal arrays but high-resolution imaging has been hampered by the relatively poor spatial resolution (and fewer independent pixels) compared to film. A partial solution to this problem, presented in this paper, are to design detectors with larger effective pixel sizes and with more pixels. A CCD detector with a much greater number of 'independent' pixels, achieved by tiling a 2x2 array of CCDs, each of which has 1242x1152 pixels is described here. The sensitive area of the detector, using fibre optics with a demagnification of 2.5 : 1, is 140x130 mm sup 2; the pixel size is 56 mu m square and there is a total of approx 2500x2300 pixels.

  11. A fibre optic sensor for the in situ determination of rock physical properties

    CERN Document Server

    Reinsch, Thomas; Milsch, Harald; Bremer, Kort; Lewis, Elfed; Leen, Gabriel; Lochmann, Steffen; 10.1016/j.ijrmms.2012.06.011

    2012-01-01

    To understand the behaviour of rocks under changing load or temperature conditions, the determination of physical parameters like pore pressure or temperature within the pore space is essential. Within this study, the implementation of a novel fibre optic point sensor for pressure and temperature determination into a high pressure / high temperature triaxial cell is presented. For the first time, pressure was measured directly within the pore space of a Flechtinger sandstone specimen during a hydrostatic compression test at up to 70 MPa. The sensor used within this study consists of a miniature all-silica fibre optic Extrinsic Fabry-Perot Interferometer (EFPI) sensor which has an embedded Fibre Bragg Grating (FBG) reference sensor element to determine temperature and pressure directly at the point of measurement.

  12. A simple model for fibre optics: planar dielectric waveguides in rotation

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Ocon, F [Departamento de Optica, Universidad de Granada, 18071 Granada (Spain); Pena, A [Valeo Iluminacion, 23600 Martos, Jaen (Spain); Jimenez, J R [Departamento de Optica, Universidad de Granada, 18071 Granada (Spain); Diaz, J A [Departamento de Optica, Universidad de Granada, 18071 Granada (Spain)

    2006-05-01

    In planar dielectric waveguides, there is only one type of propagated ray: the one that crosses the waveguide axis after each total internal reflection. According to the model of geometrical optics, there are two types of guided ray in fibre optics: meridional and skew. Each one is formulated by a suitable mathematical treatment. In this work, we demonstrate that the complex mathematical treatment for the skew rays can be avoided by considering a planar waveguide (with the same refractive index profile as the fibre and thickness equal to its diameter) that rotates around the direction of the axis with angular velocity {omega}. A section of this fibre is inscribed in the hypothetical slab. This model has been successfully introduced to students of engineering and physics.

  13. Fibre-optic coupling to high-resolution CCD and CMOS image sensors

    Science.gov (United States)

    van Silfhout, R. G.; Kachatkou, A. S.

    2008-12-01

    We describe a simple method of gluing fibre-optic faceplates to complementary metal oxide semiconductor (CMOS) active pixel and charge coupled device (CCD) image sensors and report on their performance. Cross-sectional cuts reveal that the bonding layer has a thickness close to the diameter of the individual fibres and is uniform over the whole sensor area. Our method requires no special tools or alignment equipment and gives reproducible and high-quality results. The method maintains a uniform bond layer thickness even if sensor dies are mounted at slight angles with their package. These fibre-coupled sensors are of particular interest to X-ray imaging applications but also provide a solution for compact optical imaging systems.

  14. Fibre-optic UV systems for gas and vapour analysis

    Energy Technology Data Exchange (ETDEWEB)

    Eckhardt, H S [University of Applied Sciences Giessen-Friedberg, Wilhelm-Leuschner-Str, 13, 61169 Friedberg (Germany); Klein, K-F [University of Applied Sciences Giessen-Friedberg, Wilhelm-Leuschner-Str, 13, 61169 Friedberg (Germany); Spangenberg, B [University of Applied Sciences Offenburg, Badstrasse 24, 77652 Offenburg (Germany); Sun, T [City University London, Northampton Square, London, EC1V 0HB (United Kingdom); Grattan, K T V [City University London, Northampton Square, London, EC1V 0HB (United Kingdom)

    2007-10-15

    The identification and quantification of compounds in the gas phase becomes of increasing interest in the context of environmental protection, as well as in the analytical field. In this respect, the high extinction coefficients of vapours and gases in the ultraviolet wavelength region allow a very sensitive measurement system. In addition, the increased performance of the components necessary for setting up a measurement system, such as fibres, light sources and detectors has been improved. In particular the light sources and detectors offer improved stability, and the deep UV performance and solarisation resistance of fused silica fibres allow have been significantly optimized in the past years. Therefore a compact and reliable detection system with high measuring accuracy is developed. Within this paper possible applications of the system under development and recent results will be discussed.

  15. Estimation of skin phototypes with optical parameters: an experimental study using newly developed fibre optic detection device.

    Science.gov (United States)

    Ries, F; Kapoustina, V; Kron, A; Fink, A; Rädle, M

    2013-02-01

    In an experimental study (October 2010 Mannheim Germany) with 99 Caucasian volunteers, the skin colour (L*, a*, b*) and the reflectance spectra of human skin were compared to the Fitzpatrick's sun-reactive skin photo types (SPT). For this purpose, the skin colour and the reflectance spectra of human skin were determined using non-invasive method with a newly developed fibre optic detection device. The device, based on reflectance spectroscopy, was designed and optimized using a commercial optical analysis Software. By means of the measured spectra of scattered light, the colour values and the absorption spectra of the skin were calculated. Neither any of the L*, a*, b* colour values nor any of the parameters of the absorbance spectra can be used alone to assess the skin type properly. Therefore, an ordinal logistic regression analysis was performed, using the statistical computing software r, to correlate the skin types with the measured optical parameters. It turned out that the detection device combined with the extended statistical analysis gives a better estimate of skin type in respect of the measured optical parameters than a procedure with only L*, a*, b* colour values. Even with the extended methodology, the procedure gives only a rough estimation of the skin type.

  16. Dense central office solution for point-to-point fibre access including a novel compact dual bi-directional fibre optical transceiver

    Science.gov (United States)

    Arvidsson, Gunnar; Junique, Stéphane; Persson, Karl-Åke; Sundberg, Erland

    2006-07-01

    The centralized Point-to-Point fibre access approach with a dedicated single mode optical fibre link connecting each customer to a Central Office (CO) has advantages regarding future-proofness, security, and simple and low-cost optical links and transceivers. The potential bottleneck in handling the large number of optical fibres that need to be terminated in the CO, and combined with optoelectronic components, has been studied within the IST 6th Framework Programme integrated project MUSE. The key parts in the CO are the passive cabinet where customer fibres are accessible through fibre connectors in the Optical Distribution Frame (ODF), and the active cabinet with switching equipment and optical transceivers. For the passive cabinet we conclude, that the most efficient solution is that each connection from the active cabinet to a customer passes only one ODF, and that small form factor connectors are used. For the active cabinet we have demonstrated the feasibility of an SFF-size module containing two bi-directional transceiver units by building and successfully testing a prototype, increasing the customer port density by a factor of two compared to commercial transceivers. The power consumption, which impacts power supply, cooling and cost, has been analyzed, and we propose measures to significantly decrease the power consumption.

  17. Deformation Measurement of a Driven Pile Using Distributed Fibre-optic Sensing

    Science.gov (United States)

    Monsberger, Christoph; Woschitz, Helmut; Hayden, Martin

    2016-03-01

    New developments in distributed fibre-optic sensing allow the measurement of strain with a very high precision of about 1 µm / m and a spatial resolution of 10 millimetres or even better. Thus, novel applications in several scientific fields may be realised, e. g. in structural monitoring or soil and rock mechanics. Especially due to the embedding capability of fibre-optic sensors, fibre-optic systems provide a valuable extension to classical geodetic measurement methods, which are limited to the surface in most cases. In this paper, we report about the application of an optical backscatter reflectometer for deformation measurements along a driven pile. In general, pile systems are used in civil engineering as an efficient and economic foundation of buildings and other structures. Especially the length of the piles is crucial for the final loading capacity. For optimization purposes, the interaction between the driven pile and the subsurface material is investigated using pile testing methods. In a field trial, we used a distributed fibre-optic sensing system for measuring the strain below the surface of an excavation pit in order to derive completely new information. Prior to the field trial, the fibre-optic sensor was investigated in the laboratory. In addition to the results of these lab studies, we briefly describe the critical process of field installation and show the most significant results from the field trial, where the pile was artificially loaded up to 800 kN. As far as we know, this is the first time that the strain is monitored along a driven pile with such a high spatial resolution.

  18. 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 p

  19. High-speed chaotic communication using an optical fibre ring as a key

    Institute of Scientific and Technical Information of China (English)

    Zou Lin; Feng Ye; Yang Yi-Biao; Wang An-Bang; Yang Ling-Zhen; Zhang Jian-Zhong

    2011-01-01

    A chaotic communication scheme with a fibre ring inserted in the optical feedback of the transmitter laser as an additional key is proposed under anticipating synchronization. The numerical results show that the key can enhance the communication security effectively. It is theoretically safe for the communication scheme to transmit messages with a frequency beyond the relaxation oscillation frequency.

  20. 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...

  1. Hybrid optical-fibre/geopolymer sensors for structural health monitoring of concrete structures

    Science.gov (United States)

    Perry, M.; Saafi, M.; Fusiek, G.; Niewczas, P.

    2015-04-01

    In this work, we demonstrate hybrid optical-fibre/geopolymer sensors for monitoring temperature, uniaxial strain and biaxial strain in concrete structures. The hybrid sensors detect these measurands via changes in geopolymer electrical impedance, and via optical wavelength measurements of embedded fibre Bragg gratings. Electrical and optical measurements were both facilitated by metal-coated optical fibres, which provided the hybrid sensors with a single, shared physical path for both voltage and wavelength signals. The embedded fibre sensors revealed that geopolymer specimens undergo 2.7 mɛ of shrinkage after one week of curing at 42 °C. After curing, an axial 2 mɛ compression of the uniaxial hybrid sensor led to impedance and wavelength shifts of 7 × 10-2 and -2 × 10-4 respectively. The typical strain resolution in the uniaxial sensor was 100 μ \\varepsilon . The biaxial sensor was applied to the side of a concrete cylinder, which was then placed under 0.6 mɛ of axial, compressive strain. Fractional shifts in impedance and wavelength, used to monitor axial and circumferential strain, were 3 × 10-2 and 4 × 10-5 respectively. The biaxial sensor’s strain resolution was approximately 10 μ \\varepsilon in both directions. Due to several design flaws, the uniaxial hybrid sensor was unable to accurately measure ambient temperature changes. The biaxial sensor, however, successfully monitored local temperature changes with 0.5 °C resolution.

  2. 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 temp...

  3. 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…

  4. Geometric Phases for Photons in an Optical Fibre and Some Related Predictions

    Institute of Scientific and Technical Information of China (English)

    高孝纯

    2002-01-01

    We propose a quantum electrodynamic model for the description of the time evolution of the quantum states of the photons in an optical fibre. By means of this model, we are able to make three interesting predicticons related to the geometric phases for photons.

  5. Comparative experiments between a conventional piezo hydrophone system and a fibre optic hydrophone system

    NARCIS (Netherlands)

    Cheng, L.K.; Bruijn, D. de

    2000-01-01

    We report here the results of comparative measurements between Fibre Optic (FO) hydrophone system with our Hydrostatic Pressure Conmpensation (HPC) mechanism and a conventional piezo hydrophone system (consisting of an ITC 1042 hydrophone and a B&K2035 Analyser). The sensitivity and the dynamic rang

  6. Validation of an Endoscopic Fibre-Optic Pressure Sensor for Noninvasive Measurement of Variceal Pressure

    Directory of Open Access Journals (Sweden)

    Bin Sun

    2016-01-01

    Full Text Available In this study, the authors have developed endoscopic fibre-optic pressure sensor to detect variceal pressure and presented the validation of in vivo and in vitro studies, because the HVPG requires catheterization of hepatic veins, which is invasive and inconvenient. Compared with HVPG, it is better to measure directly the variceal pressure without puncturing the varices in a noninvasive way.

  7. Fabrication of Pure Silica Core Multimode Ultraviolet Optical Fibre Probes by Tube Etching

    Institute of Scientific and Technical Information of China (English)

    HUO Xin; PAN Shi; WU Shi-Fa

    2007-01-01

    As a light wave-guide component for transmitting ultraviolet (UV) laser pulses, pure silica core UV fibre probes have attracted a great deal of attention in the near-field optical data storage and bio-medical studies. We fabricate UV fibre probes with tips in dimension of about 2-5μm and taper angle 16° by the tube etching method, using 40% HF acid as etching solution and xylene as overlayer. Probes produced have curvy configuration with smooth surface. The yield of fine probes is rather high and etching operation greatly simplified. With higher damage threshold, pure silica core multimode UV fibre probes can be coupled into more laser power. In addition, using UV light reduces the cutoff wavelength of the fibre probes, which is in favour of increasing the transmission efficiency of the probe. Furthermore, the larger tip dimension helps to enhance the light throughput either. The advances of fabrication technique of UV optical fibre probe may further support the studies of UV light data storage, pulsed laser biosurgery and UV photolithography.

  8. Fibre laser based broadband THz imaging systems

    DEFF Research Database (Denmark)

    Eichhorn, Finn

    State-of-the-art optical fiber technology can contribute towards complex multi-element broadband terahertz imaging systems. Classical table-top terahertz imaging systems are generally limited to a single emitter/receiver pair, which constrains their imaging capability to tedious raster scanning...... 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...

  9. Polarization dependent dispersion and its impact on optical parametric process in high nonlinear microstructure fibre

    Institute of Scientific and Technical Information of China (English)

    Xiao Li; Zhang Wei; Huang Yi-Dong; Peng Jiang-De

    2008-01-01

    High nonlinear microstructure fibre (HNMF) is preferred in nonlinear fibre optics, especially in the applications of optical parametric effects, due to its high optical nonlinear coefficient. However, polarization dependent dispersion will impact the nonlinear optical parametric process in HNMFs. In this paper, modulation instability (MI) method is used to measure the polarization dependent dispersion of a piece of commercial HNMF, including the group velocity dispersion, the dispersion slope, the fourth-order dispersion and group birefringence. It also experimentally demonstrates the impact of the polarization dependent dispersion on the continuous wave supercontinuum (SC) generation. On one axis MI sidebands with symmetric frequency dctunings are generated, while on the other axis with larger MI frequency detuning, SC is generated by soliton self-frequency shift.

  10. 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.

  11. Second-Harmonic Generation in Optical Fibres Induced by a Cross-Phase Modulation Effect

    Institute of Scientific and Technical Information of China (English)

    CUI Wei-Na; HUANG Guo-Xiang

    2005-01-01

    @@ When two optical pulses copropagate inside a single-modefibre, intensity-dependent refractive index couples the pulses through a cross-phase modulation (XPM). We show that a second-harmonic generation (SHG) on a continuous-wave background is possible in the optical fibre induced by the XPM effect. By means of a multiscale method the nonlinearly coupled envelope equations for the SHG are derived and their explicit solutions are provided and discussed.

  12. Thermoluminescence Responses of Photon and Electron Irradiated Ge- and Al-Doped SiO2 Optical Fibres

    Institute of Scientific and Technical Information of China (English)

    H. Wagiran; I. Hossain; D. Bradley; A. N. H. Yaakob; T. Ramli

    2012-01-01

    We carry out a comparison of the thermoluminescence (TL) response of photon and electron irradiated Ge- and Al-doped SiO2 optical fibres,as well as cross-comparison with that of TLD-100.Irradiation is made with 6 MeV electrons and 6 MV photons,for doses ranging from 0.2 Gy to 4.0Gy.The commercially available Al- and Gedoped optical fibres produce a linear dose-TL response.The TL yield for both of the doped fibres and also for TLD-100 is greater for electron irradiation than for photon irradiation.The TL yield of the Al-doped fibres is a small fraction of that of Ge-doped fibres (by a factor of 25),the Ge-doped fibres offering a response of 59%o of that of TLD-100.%We carry out a comparison of the thermoluminescence (TL) response of photon and electron irradiated Ge- and Al-doped SiO2 optical fibres, as well as cross-comparison with that of TLD-100. Irradiation is made with 6 MeV electrons and 6MV photons, for doses ranging from 0.2 Gy to 4.0Gy. The commercially available Al- and Ge-doped optical fibres produce a linear dose-TL response. The TL yield for both of the doped fibres and also for TLD-100 is greater for electron irradiation than for photon irradiation. The TL yield of the Al-doped fibres is a small fraction of that of Ge-doped fibres (by a factor of 25), the Ge-doped fibres offering a response of 59% of that of TLD-100.

  13. Influence of a thin metal layer on a beam propagation in a biconical optical fibre taper

    Science.gov (United States)

    Stasiewicz, K. A.; Moś, J. E.

    2016-12-01

    The paper presents results of a simulation of the plasmon effect achieved between a thin precious metal layer and a biconical optical fibre taper, manufactured on a standard single mode fibre. Gold, silver and titanium were used as a metal which fulfilled a cladding function for a small diameter structure. For simulation Mode Solution software was used on which modal and frequency analyses of a wavelength were provided in the range of 800-1700 nm. A displacement of a plasmon pick in dependence of thickness of a deposited precious layer for the highest plasmon effects was observed.

  14. Static and dynamic pile testing of reinforced concrete piles with structure integrated fibre optic strain sensors

    Science.gov (United States)

    Schilder, Constanze; Kohlhoff, Harald; Hofmann, Detlef; Basedau, Frank; Habel, Wolfgang R.; Baeßler, Matthias; Niederleithinger, Ernst; Georgi, Steven; Herten, Markus

    2013-05-01

    Static and dynamic pile tests are carried out to determine the load bearing capacity and the quality of reinforced concrete piles. As part of a round robin test to evaluate dynamic load tests, structure integrated fibre optic strain sensors were used to receive more detailed information about the strains along the pile length compared to conventional measurements at the pile head. This paper shows the instrumentation of the pile with extrinsic Fabry-Perot interferometers sensors and fibre Bragg gratings sensors together with the results of the conducted static load test as well as the dynamic load tests and pile integrity tests.

  15. Many-body quantum dynamics of polarisation squeezing in optical fibre

    CERN Document Server

    Corney, J F; Heersink, J; Josse, V; Leuchs, G; Andersen, U L

    2006-01-01

    We report new experiments that test quantum dynamical predictions of polarization squeezing for ultrashort photonic pulses in a birefringent fibre, including all relevant dissipative effects. This exponentially complex many-body problem is solved by means of a stochastic phase-space method. The squeezing is calculated and compared to experimental data, resulting in excellent quantitative agreement. From the simulations, we identify the physical limits to quantum noise reduction in optical fibres. The research represents a significant experimental test of first-principles time-domain quantum dynamics in a one-dimensional interacting Bose gas coupled to dissipative reservoirs.

  16. 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...

  17. Structural Engineering Properties of Fibre Reinforced Concrete Based On Recycled Glass Fibre Polymer (GFRP

    Directory of Open Access Journals (Sweden)

    Adetiloye A

    2015-04-01

    Full Text Available Glass fibre reinforced plastics (GFRP based on resin recovered from recycling plastic waste has been shown to possess mechanical properties satisfying normative requirements. This paper investigates the flexural behavior of concrete beams reinforced with GFRP produced from resin recovered from recycled plastic wastes. A total of twelve of beams of sizes 150 ×150 ×900mm and 100 × 100 × 500mm reinforced with GFRP made from recycled glass fibre reinforced polymer was tested. The flexural test results yielded lower ultimate load, lower stiffness and larger deflections at the same load when compared with the control steel reinforced beam. However, the ultimate flexural strength of beams, reinforced with GFRP from recycled resin was at least four times higher than that of the control unreinforced beam. This is in agreement, quantitatively and qualitatively, with the trend of these parameters in GFRP reinforced concrete based on virgin resins. The results therefore confirm the applicability for structural uses of GFRP reinforcement made from recycled plastic waste, with the accompanying benefits of wealth creation, value addition and environmental sustainability.

  18. High-Frequency RIN Transfer in Fibre Optic Parametric Amplifiers

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Lund-Hansen, Toke; Kang, Ning

    2011-01-01

    ibre optic parametric amplifiers (FOPAs) are versatile devices for amplification at arbitrary wavelengths, as well as a wide range of optical signal processing applications, including switching, wavelength conversion, regeneration, pulse generation etc [1]. Transfer of intensity fluctuations from...

  19. Hybrid UWB and WiMAX radio-over-multi-mode fibre for in-building optical networks

    Science.gov (United States)

    Perez, J.; Llorente, R.

    2014-01-01

    In this paper the use of hybrid WiMedia-defined ultra-wideband (UWB) and IEEE 802.16d WiMAX radio-over-fibre is proposed and experimentally demonstrated for multi-mode based in-building optical networks with the advantage of great immunity to optical transmission impairments. In the proposed approach, spectral coexistence of both signals must be achieved with negligible mutual interference. The experimental study performed addressed an indoor configuration with 50 μm multi-mode fibres (MMF) and 850 nm vertical-cavity surface-emitting laser (VCSEL) transmitters. The results indicate that the impact of the wireless convergence in radio-over-multi-mode fibre (RoMMF) is significant for UWB transmissions, mainly due to MMF dispersion and electrooptical (EO) devices with limited bandwidth. On the other hand, WiMAX transmission is feasible for a 300 m MMF and 30 m wireless link in the presence of UWB, with -31 dBm WiMAX EVM.

  20. 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...... a structure profile characterisation setup to analyse tune the fibre sensors in preparation for ultrasonic detection. We evaluate the suitability of the different structures and grating parameters for ultrasonic sensing. By analysing the prepared gratings, we enable the optimisation of the profile...... and a simplification of the detection regime for an optimal interferometric OAE configuration. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only....

  1. Fibre-optic sensors for partial discharge-generated ultrasound in elastomeric high-voltage insulation materials

    Science.gov (United States)

    Rohwetter, P.; Habel, W.

    2013-05-01

    Recent progress in the development of ultrasonic fibre-optic sensors for detecting acoustic emission from partial discharge in elastomeric insulations is presented. These sensors are an important part of a proposed comprehensive scheme for the fibre-optic monitoring of cable accessories. After specifying the underlying design goals the improved fibre-optic sensor design is outlined. It is experimentally shown that it offers about ten-fold improvement over a previously investigated resonant cantilever-type design in terms of detection limit, making it competitive with conventional piezoelectric transducers, however with the added compatibility with strong electrical fields and electromagnetically noisy environments.

  2. 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.

    2016-12-01

    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.

  3. 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

    introduced. They use another working principle to obtain the same parameters, but the settings of most of the measuring variables are not standardized. The present study has investigated aspects that have to be taken into account when the roughness of short fibre reinforced thermoplastics is measured...... identical values, whereas significantly higher roughnesses were measured with one of the two optical instruments. The optical instruments were identical but with different settings of the control parameters, which resulted in large deviations between the values measured. Some of the differences between...... 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...

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

    Indian Academy of Sciences (India)

    A Zendehnam; M Mirzaei; A Farashiani; L Horabadi Farahani

    2010-04-01

    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 loss also have been investigated. Variations of bending loss with these two parameters have been measured, loss with number of turns and radius of curvature have been measured, and with the help of computer curve fitting method, semi-empirical relationships between bending loss and these two parameters have been found, which show good agreement with the obtained experimental results.

  5. 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....

  6. Octave-spanning supercontinuum generation in highly nonlinear silica fibres based on cost-effective fibre amplifiers

    Science.gov (United States)

    Saldaña-Díaz, J. E.; Jarabo, S.; Salgado-Remacha, F. J.

    2016-09-01

    We report a simple method for supercontinuum generation. The set-up consists of an Er-doped mode-locked fibre laser, used as seed, and a highly nonlinear fibre with zero dispersion at 1550 nm. Thus, all the components are easily attainable. With this novel system the requirements in terms of control of dispersion are reduced. In addition, the spectral width is optimized using fibres with positive and negative dispersion. The supercontinuum emission is characterized by means of an optical spectrum analyser and a PbS photodetector, showing an octave-spanning spectral width, with a flat profile from 1100 nm up to 2100 nm. Compared to other supercontinuum sources, this new proposal results in a very competitive and attainable system, particularly in the 1500-2100 nm region.

  7. Thermoluminescent sensitivity of single clad neodymium doped SiO2 optical fibres measured with 6 MeV photons

    Science.gov (United States)

    Saeed, M. A.; Hossain, I.; Hida, N.; Wagiran, H.

    2013-10-01

    This study investigates the thermoluminescent sensitivity of neodymium doped SiO2 optical fibre with various dose ranges from 0.5 Gy to 4.0 Gy by 6 MeV photon irradiations. The TL responses of the neodymium doped silica fibres are compared with available TLD-100 dosimeter in order to determine the suitability as a TL material. We found that the TLD-100 and neodymium doped silica fibre have a significant linear signal to dose relationship. Neodymium doped fibres sensitivity is approximately 11% of TLD-100.

  8. Review of current strategies to induce self-healing behaviour in fibre reinforced polymer based composites

    NARCIS (Netherlands)

    Zwaag, van der S.; Grande, A.M.; Post, W.; Garcia, S.J.; Bor, T.C.

    2014-01-01

    This paper addresses the various strategies to induce self-healing behaviour in fibre reinforced polymer based composites. A distinction is made between the extrinsic and intrinsic healing strategies. These strategies can be applied at the level of the fibre, the fibre/matrix interface or at the lev

  9. Understanding and Improving the Elastic Compressive Modulus of Fibre Reinforced Soy-Based Polyurethane Foams

    Science.gov (United States)

    Hussain, Sadakat

    Soy-based polyurethane foams (PUFs) were reinforced with fibres of different aspect ratios to improve the compressive modulus. Each of the three fibre types reinforced PUF differently. Shorter micro-crystalline cellulose fibres were found embedded inside the cell struts of PUF and reinforced them. The reinforcement was attributed to be stress transfer from the matrix to the fibre by comparing the experimental results to those predicted by micro-mechanical models for short fibre reinforced composites. The reinforced cell struts increased the overall compressive modulus of the foam. Longer glass fibres (470 microns, length) provided the best reinforcement. These fibres were found to be larger than the cell diameters. The micro-mechanical models could not predict the reinforcement provided by the longer glass fibres. The models predicted negligible reinforcement because the very low modulus PUF should not transfer load to the higher modulus fibres. However, using a finite element model, it was determined that the fibres were providing reinforcement through direct fibre interaction with each other. Intermediate length glass fibres (260 microns, length) were found to poorly reinforce the PUF and should be avoided. These fibres were too short to interact with each other and were on average too large to embed and reinforce cell struts. In order to produce natural fibre reinforced PUFs in the future, a novel device was invented. The purpose of the device is to deliver natural fibres at a constant mass flow rate. The device was found to consistently meter individual loose natural fibre tufts at a mass flow rate of 2 grams per second. However, the device is not robust and requires further development to deliver a fine stream of natural fibre that can mix and interact with the curing polymeric components of PUF. A design plan was proposed to address the remaining issues with the device.

  10. Design of Precise Temperature Control System of the Fibre Optic Gyroscope Based on Dual MSP430 Chip%基于双MSP430芯片的光纤陀螺精密温控系统设计

    Institute of Scientific and Technical Information of China (English)

    刘云

    2014-01-01

    The stability of the fibre optic gyroscope drift is concerned with the temperature of working envi-ronment, whose nonuniform-distribution affects the stability of the gyroscope, and then causes its drift, as well as the inaccuracy in parameters. So the design of a precise system to control its environment temperature is important to practical engineering. This paper, based on a college project, designs a precise temperature control system for the gyroscope, with modules for a precise control of the temperature of working environment. The system has strong generality, and the design of its modules makes it easy to install and debug. The results show that the tem-perature measurement can be precisely reached.%光纤陀螺漂移的稳定性与温度之间存在很大关联,温度场的不均匀将影响光源稳定性等参数,从而引起陀螺漂移;同时由于环境温度不均匀也会造成陀螺参数标定测试结果不准确。因此设计精密温控系统来保障光纤陀螺等精密惯性元件的工作环境,对于提高陀螺精度具有重要的实际意义。本文以实际工程为背景,设计光纤陀螺仪温度控制系统,以模块化的设计实现工作环境温度的精密控制。本系统具有较强的通用性,模块化的设计可使系统便于安装和调试,最终能够使系统测温精度达到要求。

  11. COMMERCIAL VIABILITY ANALYSIS OF LIGNIN BASED CARBON FIBRE

    OpenAIRE

    2014-01-01

    Lignin is a rich renewable source of aromatic compounds. As a potentialpetroleum feedstock replacement, lignin can reduce environmental impacts such ascarbon emission. Due to its complex chemical structure, lignin is currently underutilized.Exploiting lignin as a precursor for carbon fibre adds high economic value to lignin andencourages further development in lignin extraction technology. This report includes apreliminary cost analysis and identifies the key aspects of lignin-based carbon fi...

  12. 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...

  13. Chinese Market for Fibres and Cables

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    This article presents a summary of Chinese market of optical fibres and cables based on the development of the optical communications industry. Analysis shows that the market will keep growing for sometime in the future.

  14. Polarization Maintaining Fibre Loop Mirror for NRZ-to-PRZ Conversion in All-Optical Clock Recovery

    Institute of Scientific and Technical Information of China (English)

    XU Fan; ZHANG Xin-Liang; LIU Hai-Rong; LIU De-Ming; HUANG De-Xiu

    2006-01-01

    @@ We propose a novel configuration for clock extraction by converting the NRZ data into the PRZ data and by employing a polarization-maintaining fibre loop mirror (PMFLM) which is usually used as an optical comb filter.

  15. Effects of {gamma} and neutron irradiation on the optical absorption of pure silica core single-mode optical fibres from Nufern

    Energy Technology Data Exchange (ETDEWEB)

    Calderon, A. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Martinez-Rivero, C. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Matorras, F. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Rodrigo, T. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Sobron, M. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Vila, I. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Virto, A.L. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Alberdi, J. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Arce, P. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Barcala, J.M. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Calvo, E. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Ferrando, A. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain)]. E-mail: Antonio.Ferrando@ciemat.es; Josa, M.I. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Luque, J.M. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Molinero, A. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Navarrete, J. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Oller, J.C. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Valdivieso, P. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Yuste, C. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Fenyvesi, A. [Institute of Nuclear Research, ATOMKI, Debrecen (Hungary); Molnar, J. [Institute of Nuclear Research, ATOMKI, Debrecen (Hungary)

    2006-09-15

    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{sup 14} cm{sup -2} and the induced optical absorption was evaluated for four different wavelengths: 630, 670, 681 and 785 nm.

  16. Operation Manual for the Intensity Based Interrogation of Fibre Bragg Grating Arrays on Vibrating Structures

    Science.gov (United States)

    2011-01-01

    factors for each FBG on the array. In this mode the configuration files are loaded prior to the experiment and the fibre optic switch box automatically... fibre - optic inputs and check the ‘Ext Trig’ and ‘Save All Data’ boxes UNCLASSIFIED 9 UNCLASSIFIED DSTO-TN-0985 2.12 Scan the Array This scans...the gratings in reflection)  Switchbox: Set the channels on the switchbox 1 to match the fibre - optic inputs and check the ‘Ext Trig’ and ‘Save All

  17. New radiation-induced effects in optical fibres feasible for dosimetry; Nouveaux effets induits par rayonnement dans des fibres optiques dediees a la dosimetrie

    Energy Technology Data Exchange (ETDEWEB)

    Tomashuk, A.L.; Golant, K.M.; Dianov, E.M.; Nikolin, I.V. [Fibre Optics Research Centre (FORC), Moscow (Russian Federation); Zakharkin, I.I.; Stepanov, V.A. [Institute of Physics and Power Engineering, SSC RF, Obninsk (Russian Federation)

    1999-07-01

    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 {sub 7}N{sup 14}({sub 0}n{sup 1},{sub 1}p{sup 1}){sub 6}C{sup 14} occurs and produces protons with energy 620 keV. With this energy, propagation length of protons in silica is 7 {mu}m which means that the escape of protons from a 50 {mu}m 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. Performance comparison of bismuth/erbium co-doped optical fibre by 830 nm and 980 nm pumping

    Science.gov (United States)

    Yan, Binbin; Luo, Yanhua; Zareanborji, Amirhassan; Xiao, Gui; Peng, Gang-Ding; Wen, Jianxiang

    2016-10-01

    The performance of bismuth/erbium co-doped fibre (BEDF) by 830 nm and 980 nm pumping has been studied in detail, including the small signal absorption, pump absorption, emission, gain and excited state absorption (ESA). Based on the study, energy transition diagrams of BEDF under 830 nm or 980 nm pumping are proposed to clarify the spectroscopic properties. The results demonstrate the advantages of 830 nm pumping for BEDF over 980 nm pumping when considering the absorption, pumping efficiency, excited state absorption and optical amplification.

  19. 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.

  20. Comprehensive research on self phase modulation based optical delay systems

    Institute of Scientific and Technical Information of China (English)

    Yang Ai-Ying; Sun Yu-Nan

    2010-01-01

    This paper comprehensively investigates the properties of self phase modulation based optical delay systems consisting of dispersion compensation fibre and highly nonlinear fibres.It researches into the impacts of power level launched into highly nonlinear fibres,conversion wavelength,dispersion slope,modulation format and optical filter bandwidth on the overall performance of optical delay systems.The results reveal that,if the power launched into highly nonlinear fibres is fixed,the time delay generally varies linearly with the conversion wavelength,but jumps intermittently at some conversion wavelengths.However,the time delay varies semi-periodically with the power launched into highly nonlinear fibres.The dispersion slope of highly nonlinear fibres has significant influence on the time delay,especially for the negative dispersion slope.The time delay differs with modulation formats due to the different combined interaction of nonlinearity and dispersion in fibres.The bandwidth of the optical filters also greatly affects the time delay because it determines the bandwidth of the passed signal in the self phase modulation based time delay systems.The output signal quality of the overall time delay systems depends on the conversion wavelength and input power level.The optimisation of the power level and conversion wavelength to provide the best output signal quality is made at the end of this paper.

  1. Experimental Investigation on a Fibre-Optic Hydrophone with a Cylindrical Helmholtz Resonator

    Institute of Scientific and Technical Information of China (English)

    WANG Ze-Feng; HUNG Yong-Ming; MENG Zhou; NI Ming

    2008-01-01

    A novel mechanical anti-aliasing filtering fibre-optic hydrophone with a cylindrical Helmholtz resonator is constructed and tested.The experimental results show that the hydrophone has a function of low-pass filtering.The low frequency acoustic sensitivity is about -160 dB (1 rad/μPa),and the response curve has a resonance determined by the Helmholtz resonator.Theoretical and experimental results both show that the resonant frequency moves towards high frequency with the increasing orifice diameters.The sensitivity attenuation of high frequency is larger than 10 dB.This new fibre-optic hydrophone is a prototype device for a c/ass of sensors used to eliminate the aliasing in future sonar systems.

  2. Temperature-Insensitive Chemical Sensor with Twin Bragg Gratings in an Optical Fibre

    Institute of Scientific and Technical Information of China (English)

    SANG Xin-Zhu; YU Chong-Xiu; YAN Bin-Bin; MA Jian-Xin; MENG Zhao-Fang; Mayteevarunyoo T.; LU Nai-Guang

    2006-01-01

    To reduce temperature sensitivity of the fibre Bragg grating (FBG) chemical sensor, a simple method is proposed by measuring the peak wavelength difference between an etched FBG and an un-etched one in an optical fibre.Thermal characteristics and chemical sensitivity of the sensor are experimentally investigated. The experimental results indicate that the etched FBG and the rest one have almost the same thermal response, and concentration changes of the surrounding chemical solutions can be detected by measuring the peak wavelength difference between them. The sensor has been used to measure the concentrations of propylene glycol solutions and sugar solutions, and it could detect 0.7% and 0.45% concentration changes for them with an optical spectrum analyser in resolution of 10pm.

  3. Direct optical activation of skeletal muscle fibres efficiently controls muscle contraction and attenuates denervation atrophy.

    Science.gov (United States)

    Magown, Philippe; Shettar, Basavaraj; Zhang, Ying; Rafuse, Victor F

    2015-10-13

    Neural prostheses can restore meaningful function to paralysed muscles by electrically stimulating innervating motor axons, but fail when muscles are completely denervated, as seen in amyotrophic lateral sclerosis, or after a peripheral nerve or spinal cord injury. Here we show that channelrhodopsin-2 is expressed within the sarcolemma and T-tubules of skeletal muscle fibres in transgenic mice. This expression pattern allows for optical control of muscle contraction with comparable forces to nerve stimulation. Force can be controlled by varying light pulse intensity, duration or frequency. Light-stimulated muscle fibres depolarize proportionally to light intensity and duration. Denervated triceps surae muscles transcutaneously stimulated optically on a daily basis for 10 days show a significant attenuation in atrophy resulting in significantly greater contractile forces compared with chronically denervated muscles. Together, this study shows that channelrhodopsin-2/H134R can be used to restore function to permanently denervated muscles and reduce pathophysiological changes associated with denervation pathologies.

  4. Enhanced Transmission Stability of Polarization Solitons in Birefringent Fibres with an Optical Phase Conjugator

    Institute of Scientific and Technical Information of China (English)

    陈伟成; 谢嘉宁; 路洪; 徐文成

    2003-01-01

    An optical phase conjugator is used to enhance transmission stability of polarization solitons in highly birefringent fibres. Two polarization solitons form a breather in fibres with low birefringence firstly and the optical phase conjugator is used to make the spectra of polarization solitons converse, which results in the fact that the polarization soliton along the fast axis is compressed due to the strengthened self-phase modulation effect. Two polarization solitons are compressed further due to the cross-phase modulation effect. The enhanced nonlinear effects make the central peak frequencies of two polarization solitons shift to the larger range in opposite directions so that they trap each other fully to suppress the effect of birefringence.

  5. 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....

  6. Demodulating the Response of Optical Fibre Long-Period Gratings: Genetic Algorithm Approach

    Institute of Scientific and Technical Information of China (English)

    P. S. André; R. A. Sá. Ferreira; C. M. L. Correia; H. Kalinowshy; XIN Xiang-Jun; J. L. Pinto

    2006-01-01

    @@ The extraction of the physical parameters of long period gratings from the spectral response is not an easy process. We present a demodulation technique to synthesize the physical parameters of a long period grating recorded in an optical fibre. The demodulation is achieved through the implementation of a genetic algorithm.The extracted parameters are in agreement with the typical values known for long period gratings.

  7. Railway track component condition monitoring using optical fibre Bragg grating sensors

    Science.gov (United States)

    Buggy, S. J.; James, S. W.; Staines, S.; Carroll, R.; Kitson, P.; Farrington, D.; Drewett, L.; Jaiswal, J.; Tatam, R. P.

    2016-05-01

    The use of optical fibre Bragg grating (FBG) strain sensors to monitor the condition of safety critical rail components is investigated. Fishplates, switchblades and stretcher bars on the Stagecoach Supertram tramway in Sheffield in the UK have been instrumented with arrays of FBG sensors. The dynamic strain signatures induced by the passage of a tram over the instrumented components have been analysed to identify features indicative of changes in the condition of the components.

  8. 3D printed sensing patches with embedded polymer optical fibre Bragg gratings

    Science.gov (United States)

    Zubel, Michal G.; Sugden, Kate; Saez-Rodriguez, D.; Nielsen, K.; Bang, O.

    2016-05-01

    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/μepsilon. Its temperature behaviour is unstable, with temperature sensitivity values varying between 30-40 pm/°C.

  9. Design and clinical results from a fibre optic manometry catheter for oesophageal motility studies

    Science.gov (United States)

    Arkwright, J. W.; Doe, S. N.; Smith, M. C.; Blenman, N. G.; Underhill, I. D.; Maunder, S. A.; Glasscock, J. A.; Lim, B.; Szczesniak, M. M.; Dinning, P. G.; Cook, I. J.

    2008-04-01

    We report the design and operation of an optical fibre manometry catheter for measuring variation in pressure in the oesophagus during peristalsis. Catheters of this kind are used to help diagnose oesophageal disorders by recording the muscular contractions of the oesophageal wall in patients having difficulty swallowing. Traditional oesophageal catheters consist of an array of recording sites enabling pressure measurement from multiple locations along the the oesophagus. However, these catheters tend to be bulky or complex to operate whereas our optical equivalent uses a series of Fibre Bragg Grating (FBG) pressure sensors on a single fibre; significantly reducing complexity and allowing the catheter diameter to be minimised. The data from each FBG was recorded using a solid state spectrometer in which the reflected peaks each covered a number of pixels of the spectrometer. This has enabled the FBG peaks to be tracked in wavelength with sub-nanometre precision resulting in pressure sensitivities of less than 1mmHg. Results from a clinical trial carried out on 10 healthy subjects will be presented. For the trial, each subject was simultaneously intubated with the optical catheter and a commercially available solid-state catheter. Back-to-back readings were taken from both devices during a series of controlled water swallows. Ten swallows were recorded with the catheters sensors positioned in proximal, mid, and distal regions of the oesophagus and the data analysed statistically. The fibre optic device accurately picked up the dynamic variations in pressure, and can react at least as fast as the solid state device.

  10. [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.

  11. Active fibre optic splitter for the CMS RPC detector

    Energy Technology Data Exchange (ETDEWEB)

    Banzuzi, Kukka [Helsinki Institute of Physics, University of Helsinki, P.O. Box 64, Gustaf Haellstroemin katu 2, FIN-00014 (Finland)]. E-mail: Kukka.Banzuzi@oxinst.fi; Iskanius, Matti [Lappeenranta University of Technology, P.O, Box 20, Lapprenranta, FIN-53851 (Finland); Karjalainen, Ahti [Lappeenranta University of Technology, P.O, Box 20, Lapprenranta, FIN-53851 (Finland); Tuuva, Tuure [Lappeenranta University of Technology, P.O, Box 20, Lapprenranta, FIN-53851 (Finland)

    2006-09-15

    An electronics module has been designed and tested for the CMS RPC detector readout. The module consists of twelve sub-blocks, each of which receives an optical signal at 1.6 GHz, converts it into electronic form for the splitting process and sends it forth to two or four destinations in optical form. It is a critical part in the trigger system of the experiment. Details of the design are presented, as well as test results confirming that the splitter fulfils all system requirements.

  12. 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

  13. 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.

  14. Design, Simulation and Optimisation of a Fibre-optic 3D Accelerometer

    Science.gov (United States)

    Yang, Zhen; Fang, Xiao-Yong; Zhou, Yan; Li, Ya-lin; Yuan, Jie; Cao, Mao-Sheng

    2013-07-01

    Using an inertia pendulum comprised of two prisms, flexible beams and an elastic flake, we present a novel fibre-optic 3D accelerometer design. The total reverse reflection of the cube-corner prism and the spectroscopic property of an orthogonal holographic grating enable the measurement of the two transverse components of the 3D acceleration simultaneously, while the longitudinal component can be determined from the elastic deformation of the flake. Due to optical interferometry, this sensor may provide a wider range, higher sensitivity and better resolving power than other accelerometers. Moreover, we use finite element analysis to study the performance and to optimise the structural design of the sensor.

  15. A simplified hollow-core microstructured optical fibre laser with microring resonators and strong radial emission

    Science.gov (United States)

    Li, Zhi-Li; Liu, Yan-Ge; Yan, Min; Zhou, Wen-Yuan; Ying, Cui-Feng; Ye, Qing; Tian, Jian-Guo

    2014-08-01

    A simplified hollow-core microstructured optical fibre (SHMOF) laser with microring resonators and strong radial emission is demonstrated. We propose that a submicron thickness silica ring embedded in the SHMOF can act as a microring resonator, with the advantages of being both compact and solid. Furthermore, the microfluidics can be easily controlled with a side pumping scheme. We also obtained a highly stable and tunable laser. The attractive possibility of developing microfluidic dye lasers within single SHMOFs presents opportunities for integrated optics applications and biomedical analysis.

  16. Theoretical analysis on double Rayleigh backscattering noise in optical fibre Raman amplifiers and its suppression

    Institute of Scientific and Technical Information of China (English)

    Jiang Wen-Ning; Chen Jian-Ping; Li Xin-Wan; Shang Tao

    2004-01-01

    In this paper, amplified double Rayleigh backscattering noise (DRB) in the optical fibre Raman amplifier is analysed. Expressions are presented for both forward pumping and backward pumping schemes. Calculation is performed to show the effective suppression of DRB noise by employing an optical isolator. The optimal position for the isolator is determined and is found to be insensitive to the power levels of the signals and pumps. The results show that a reduction of the DRB noise by almost 2 to 3 orders can be reached.

  17. Dispersion spreading of biphotons in optical fibres and two-photon interference

    CERN Document Server

    Brida, G; Genovèse, M; Gramegna, M; Krivitsky, L A

    2006-01-01

    We present the first observation of two-photon polarization interference structure in the second-order Glauber's correlation function of two-photon light generated via type-II spontaneous parametric down-conversion. In order to obtain this result, two-photon light is transmitted through an optical fibre and the coincidence distribution is analyzed by means of the START-STOP method. Beyond the experimental demonstration of an interesting effect in quantum optics, these results also have considerable relevance for quantum communications.

  18. Determination of dominant fibre orientations in fibre-reinforced high-strength concrete elements based on computed tomography scans

    Science.gov (United States)

    Vicente, Miguel A.; González, Dorys C.; Mínguez, Jesús

    2014-04-01

    Computed tomography (CT) is a nondestructive technique, based on absorbing X-rays, that permits the visualisation of the internal structure of materials in micron-range resolution. In this paper, the CT scan is used to determine the position and orientation of the fibres in steel fibre-reinforced high-strength concrete elements. The aim of this paper was to present a numerical procedure, automated through a MATLAB routine specially developed by the authors, which enables, fast and reliable, to obtain the orientation of each and every one of the fibres and their centre of gravity. The procedure shown is directly extrapolated to any type of fibre-reinforced material, only if there is a wide difference between density of fibres and density of matrix. The mathematical basis of this procedure is very simple and robust. The result is a fast algorithm and a routine easy to use. In addition, the validation tests show that the error is almost zero. This algorithm can help the industry to implement the technology of CT in the protocols of product quality control.

  19. Ge-doped optical fibres as thermoluminescence dosimeters for kilovoltage X-ray therapy irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Issa, Fatma, E-mail: f.issa@surrey.ac.uk [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Latip, Nur Atiqah Abd; Bradley, David A. [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Nisbet, Andrew [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Department of Medical Physics, Royal Surrey County Hospital NHS Foundation Trust, Guildford, GU2 7XX (United Kingdom)

    2011-10-01

    We investigate key dosimetric parameters for the thermoluminescence (TL) of Ge-doped silica optical fibres irradiated by X-rays generated at 90 and 300 kVp. The parameters include dose response, reproducibility and fading. Relative dose measurements were performed, obtaining central axis percentage depth dose (PDD) values, use being made of doped fibres irradiated in water and solid water phantoms. TL yields were compared with published data and ionisation chamber measurements. Linearity to dose was demonstrated over the investigated range (0.1-6 Gy), with reproducibility to within{+-}2%. TL fading was found to be minimal, at <1.5% over a 12 h period. The RMI 457 solid water phantom correction factor was found to be 1.155{+-}0.152 and 0.955{+-}0.221 at 90 and 300 kVp, respectively. The maximum discrepancy between PDD values obtained using optical fibres and ionisation chamber measurements was 2.1% at 90 kVp, while the maximum discrepancy between tabulated data and measurements was 1.1% at 300 kVp.

  20. Challenges in Ecohydrological Monitoring at Soil-Vegetation Interfaces: Exploiting the Potential for Fibre Optic Technologies

    Science.gov (United States)

    Chalari, A.; Ciocca, F.; Krause, S.; Hannah, D. M.; Blaen, P.; Coleman, T. I.; Mondanos, M.

    2015-12-01

    The Birmingham Institute of Forestry Research (BIFoR) is using Free-Air Carbon Enrichment (FACE) experiments to quantify the long-term impact and resilience of forests into rising atmospheric CO2 concentrations. The FACE campaign critically relies on a successful monitoring and understanding of the large variety of ecohydrological processes occurring across many interfaces, from deep soil to above the tree canopy. At the land-atmosphere interface, soil moisture and temperature are key variables to determine the heat and water exchanges, crucial to the vegetation dynamics as well as to groundwater recharge. Traditional solutions for monitoring soil moisture and temperature such as remote techniques and point sensors show limitations in fast acquisition rates and spatial coverage, respectively. Hence, spatial patterns and temporal dynamics of heat and water fluxes at this interface can only be monitored to a certain degree, limiting deeper knowledge in dynamically evolving systems (e.g. in impact of growing vegetation). Fibre optics Distributed Temperature Sensors (DTS) can measure soil temperatures at high spatiotemporal resolutions and accuracy, along kilometers of optical cable buried in the soil. Heat pulse methods applied to electrical elements embedded in the optical cable can be used to obtain the soil moisture. In July 2015 a monitoring system based on DTS has been installed in a recently forested hillslope at BIFoR in order to quantify high-resolution spatial patterns and high-frequency temporal dynamics of soil heat fluxes and soil moisture conditions. Therefore, 1500m of optical cables have been carefully deployed in three overlapped loops at 0.05m, 0.25m and 0.4m from the soil surface and an electrical system to send heat pulses along the optical cable has been developed. This paper discussed both, installation and design details along with first results of the soil moisture and temperature monitoring carried out since July 2015. Moreover, interpretations

  1. Multi-Rare-Earth Ions Codoped Tellurite Glasses for Potential Dual Wavelength Fibre-Optic Amplifiers

    Institute of Scientific and Technical Information of China (English)

    DAI Shi-Xun; YANG Jian-Hu; XU Shi-Qing; DAI Neng-Li; WEN Lei; HU Li-Li; JIANG Zhong-Hong

    2003-01-01

    A novel co-doping method of multi-rare-earth (RE) ions was demonstrated in tellurite glasses for fibre amplifiers. Fluorescence emissions at both 1.53 and 1.63 fj,m communication windows were Brstly observed from Er3+ /Yb3+ /Tm3+ -codoped tellurite glasses under a single wavelength pumping at 980 nm. The full width at half maximum of Suorescence at 1.53 and 1.63 [im are 55 nm and 50 urn, respectively. Tm's codoping method of three RE ions could be applied to other low photon energy glasses, which would be possibly used for potential dual wavelength fibre-optic amplifiers to broaden the communication windows.

  2. Evanescent optical trapping of nanoscale particles using slotted tapered optical fibres

    CERN Document Server

    Daly, Mark; Chormaic, Síle Nic

    2016-01-01

    While conventional optical trapping techniques can trap objects with submicron dimensions, the underlying limits imposed by the diffraction of light generally restrict their use to larger, or higher refractive index particles. As the index and diameter decrease, the trapping difficulty rapidly increases; hence, the power requirements for stable trapping become so large as to quickly denature the trapped objects in such diffraction-limited systems. Here, we present an evanescent field-based device capable of confining low index nanoscale particles using modest optical powers as low as 1.2 mW, with additional applications in the field of cold atom trapping. Our experiment uses a nanostructured optical micro-nanofibre to trap 200 nm, low-index, fluorescent particles within the structured region, thereby overcoming diffraction limitations. We analyse the trapping potential of this device both experimentally and theoretically, and show how strong optical traps are achieved with low input powers.

  3. 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...

  4. Developing fibre optic Raman probes for applications in clinical spectroscopy.

    Science.gov (United States)

    Stevens, Oliver; Iping Petterson, Ingeborg E; Day, John C C; Stone, Nick

    2016-04-07

    Raman spectroscopy has been shown by various groups over the last two decades to have significant capability in discriminating disease states in bodily fluids, cells and tissues. Recent development in instrumentation, optics and manufacturing approaches has facilitated the design and demonstration of various novel in vivo probes, which have applicability for myriad of applications. This review focusses on key considerations and recommendations for application specific clinical Raman probe design and construction. Raman probes can be utilised as clinical tools able to provide rapid, non-invasive, real-time molecular analysis of disease specific changes in tissues. Clearly the target tissue location, the significance of spectral changes with disease and the possible access routes to the region of interest will vary for each clinical application considered. This review provides insight into design and construction considerations, including suitable probe designs and manufacturing materials compatible with Raman spectroscopy.

  5. Optical Solitons

    Science.gov (United States)

    Taylor, J. R.

    2005-08-01

    1. Optical solitons in fibres: theoretical review A. Hasegawa; 2. Solitons in optical fibres: an experimental account L. F. Mollenauer; 3. All-optical long-distance soliton-based transmission systems K. Smith and L. F. Mollenauer; 4. Nonlinear propagation effects in optical fibres: numerical studies K. J. Blow and N. J. Doran; 5. Soliton-soliton interactions C. Desem and P. L. Chu; 6. Soliton amplification in erbium-doped fibre amplifiers and its application to soliton communication M. Nakazawa; 7. Nonlinear transformation of laser radiation and generation of Raman solitons in optical fibres E. M. Dianov, A. B. Grudinin, A. M. Prokhorov and V. N. Serkin; 8. Generation and compression of femtosecond solitons in optical fibers P. V. Mamyshev; 9. Optical fibre solitons in the presence of higher order dispersion and birefringence C. R. Menyuk and Ping-Kong A. Wai; 10. Dark optical solitons A. M. Weiner; 11. Soliton Raman effects J. R. Taylor; Bibliography; Index.

  6. Decreased retinal nerve fibre layer thickness detected by optical coherence tomography in patients with ethambutol‐induced optic neuropathy

    Science.gov (United States)

    Chai, Samantha J; Foroozan, Rod

    2007-01-01

    Background It is difficult to assess the degree of optic nerve damage in patients with ethambutol‐induced optic neuropathy, especially just after the onset of visual loss, when the optic disc typically looks normal. Aim To evaluate changes in retinal nerve fibre layer thickness (RNFLT) using optical coherence tomography (OCT) in patients with optic neuropathy within 3 months of cessation of ethambutol treatment. Design A retrospective observational case series from a single neuro‐ophthalmology practice. Methods 8 patients with a history of ethambutol‐induced optic neuropathy were examined within 3 months after stopping ethambutol treatment. All patients underwent a neuro‐ophthalmologic examination, including visual acuity, colour vision, visual fields and funduscopy. OCT was performed on both eyes of each patient using the retinal nerve fibre layer analysis protocol. Results The interval between cessation of ethambutol treatment and the initial visit ranged from 1 week to 3 months. All patients had visual deficits characteristic of ethambutol‐induced optic neuropathy at their initial visit, and the follow‐up examination was performed within 12 months. Compared with the initial RNFLT, there was a statistically significant decrease in the mean RNFLT of the temporal, superior and nasal quadrants (p = 0.009, 0.019 and 0.025, respectively), with the greatest decrease in the temporal quadrant (mean decrease 26.5 μm). Conclusions A decrease in RNFLT is observed in all quadrants in patients with ethambutol‐induced optic neuropathy who have recently discontinued the medication. This decrease is most pronounced in the temporal quadrant of the optic disc. PMID:17215265

  7. Effect of alpha and Gaussian refractive index profiles on the design of highly nonlinear optical fibre for efficient nonlinear optical signal processing

    Science.gov (United States)

    Selvendran, S.; Sivanantharaja, A.; Arivazhagan, S.; Kannan, M.

    2016-09-01

    We propose an index profiled, highly nonlinear ultraflattened dispersion fibre (HN-UFF) with appreciable values of fibre parameters such as dispersion, dispersion slope, effective area, nonlinearity, bending loss and splice loss. The designed fibre has normal zero flattened dispersion over S, C, L, U bands and extends up to 1.9857 μm. The maximum dispersion variation observed for this fibre is as low as 1.61 ps km-1 nm-1 over the 500-nm optical fibre transmission spectrum. This fibre also has two zero dispersion wavelengths at 1.487 and 1.9857 μm and the respective dispersion slopes are 0.02476 and 0.0068 ps nm-2 km-1. The fibre has a very low ITU-T cutoff wavelength of 1.2613 μm and a virtuous nonlinear coefficient of 9.43 W-1 km-1. The wide spectrum of zero flattened dispersion and a good nonlinear coefficient make the designed fibre very promising for different nonlinear optical signal processing applications.

  8. Direct implementation of a scalable non-local multi-qubit controlled phase gate via optical fibres and adiabatic passage

    Institute of Scientific and Technical Information of China (English)

    Tang Yao-Xiang; Lin Xiu-Min; Lin Gong-Wei; Chen Li-Bo; Huang Xiu-Hua

    2008-01-01

    This paper presents a direct implementation scheme of the non-local multi-qubit controlled phase gate by using optical fibres and adiabatic passage. The smaller operation number for implementing the multi-qubit controlled phase gate and needlessness for addressing individually save physical resource and lower the difficulties of experiment. Meanwhile, the scheme is immune from some decoherence effects such as the atomic spontaneous emission and fibre loss. In principle, it is scalable.

  9. Raman Amplification In Optical Fibres In The Wavelength Range 1.06 To 1.36µm

    Science.gov (United States)

    Byron, K. C.

    1985-03-01

    Optical amplification by stimulated Raman emission has been observed at five discrete wavelengths using a fibre Raman laser as both signal and pumping source to the amplifier. An amplification factor of 16 dB has been observed at 1.30 μm and 3 dB at 1.36 μm for a pump power of a few tens of milliwatts. RAMAN AMPLIFICATION IN OPTICAL FIBRES IN THE WAVELENGTH RANGE 1.06 TO 1.36 μm Stimulated Raman scattering in low loss optical fibre waveguides has attracted considerable attention owing to the high efficiency of generation of multiple Stokes frequency shifts. This effect has been utilised to provide a pulsed tunable source for fibre diagnostic measurements (1) , but the direct application of this mechanism for producing amplification of the transmitted signal in a fibre has only recently been investigated, with results showing substantial amplification in GeO2 doped SiO2 fibres at 1.064 μm (2), 1.24 μm (3), and 1.4 μm (4).

  10. Creep behaviour at high temperatures of fine SiC and alumina based fibres

    Energy Technology Data Exchange (ETDEWEB)

    Berger, M.H.; Bunsell, A.R. (Ecole Nationale Superieure des Mines, 91 - Evry (France). Centre des Materiaux)

    1999-01-01

    The creep behaviours of fine ceramic fibres based on silicon carbide and alpha-alumina have been compared. Fibres based on alpha-alumina and composed of isotropic faceted submicronic grains show superplastic behaviour from 1300 C. A mullite/alpha-alumina fibre with curved and elongated grains exhibits lower creep rates but large grains which grow on the surface of the fibre from 1200 C considerably reduce the time to failure in creep. The microstructures and creep strengths of SiC based fibres are strongly dependent on the oxygen content and carbon to silicon ratio. An oxygen content of 5 wt% induces an intergranular oxygen rich phase to be formed which facilitates creep. The creep strength of a fibre containing 0.5 wt% of oxygen can be improved by a heat treatment which increases the crystallinity of the fibre. The structure of a stoichiometric SiC fibre is shown to be composed of larger and faceted grains, to have a higher elastic modulus and an improved resistance to creep. However SiC based fibre are limited in air at high temperatures by the oxidation of the surface. (orig.) 13 refs.

  11. Characterisation of a fibre optic Raman probe within a hypodermic needle.

    Science.gov (United States)

    Iping Petterson, Ingeborg E; Day, John C C; Fullwood, Leanne M; Gardner, Benjamin; Stone, Nick

    2015-11-01

    We demonstrate the first use of a multifibre Raman probe that fits inside the bore of a hypodermic needle. A Raman probe containing multiple collection fibres provides improved signal collection efficiency in biological samples compared with a previous two-fibre design. Furthermore, probe performance (signal-to-noise ratios) compared favourably with the performance achieved in previous Raman microscope experiments able to distinguish between benign lymph nodes, primary malignancies in lymph nodes and secondary malignancies in lymph nodes. The experimental measurements presented here give an indication of the sampling volume of the Raman needle probe in lymphoid tissues. Liquid tissue phantoms were used that contained scattering medium encompassing a range of scattering properties similar to those of a variety of tissue types, including lymph node tissues. To validate the appropriateness of the phantoms, the sampling depth of the probe was also measured in excised lymph node tissue. More than 50 % of Raman photons collected were found to originate from between the tip of the needle and a depth of 500 μm into the tissue. The needle probe presented here achieves spectral quality comparable to that in numerous studies previously demonstrating Raman disease discrimination. It is expected that this approach could achieve targeted subcutaneous tissue measurements and be viable for use for the in vivo Raman diagnostics of solid organs located within a few centimetres below the skin's surface. Graphical Abstract Schematic of multi-fibre Raman needle probe with disposible tips and proximal optical filtration.

  12. 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).

  13. Spectroscopic studies of atomic and molecular species relevant to the optical fibre transmission bands

    CERN Document Server

    Meldau, J

    1995-01-01

    The work presented in this thesis, although all relevant to wavelength standards in the optical fibre transmission windows at 1.3 mu m and 1.55 mu m, can be split into three main parts. Firstly, the work carried out at the University of Strathclyde concerning accurate line position measurements of some molecules having absorption bands at 1.5 mu m ( sup 1 sup 5 NH sub 3 , C sub 2 H sub 2 and sup 1 sup 3 C sup 1 sup 2 CH sub 2) and 1.3 mu m ( sup 1 sup 3 C sub 2 D-2 and sup 1 sup 2 C sub 2 D sub 2) with a Fourier transform spectrometer (FTS). The FTS measurements were undertaken primarily to provide a comprehensive list of fairly strong lines relevant to the optical fibre regions as potential wavelength references for the National Physical Laboratory (NPL). The sup 1 sup 3 C sup 1 sup 2 CH sub 2 overtone and combination bands were assigned and fitted. Secondly, the development of two diode laser spectrometers was carried out at the University of Strathclyde to perform an optical double resonance experiment in ...

  14. Fabrication of microstructured optical fibres by drawing preforms sealed at their top end

    Science.gov (United States)

    Denisov, A. N.; Kosolapov, A. F.; Senatorov, A. K.; Pal'tsev, P. E.; Semjonov, S. L.

    2016-11-01

    This paper presents results of a theoretical analysis and a series of experiments dealing with microstructured optical fibre (MOF) drawing from preforms sealed at their top end. We demonstrate that maintaining a constant temperature in the top part of the preform is of key importance for the ability to produce long MOFs with stable parameters. We have proposed and implemented a technique for additional, controlled heating of the top part of preforms, which allows one to fabricate long MOFs with both constant and varying parameters. Evidence is provided that MOFs with holes differing in size can be produced rather easily by this method.

  15. 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....... To increase the nonlinearity of the mPOFs we investigated doping of PMMA with the highly-nonlinear dye Disperse Red 1. Both doping of a PMMA cane and direct doping of a PMMA mPOF was performed....

  16. Photonic crystal fibre Brillouin laser based on Bragg grating Fabry-Perot cavity

    Institute of Scientific and Technical Information of China (English)

    Geng Dan; Yang Dong-Xiao; Shen Guo-Feng; Zhang Xian-Min

    2008-01-01

    A photonic crystal fibre Brillouin laser based on fibre Bragg grating Fabry-Perot cavity is presented. A highly nonlinear photonic crystal fibre 25 m in length is used as Brillouin gain medium and fibre Bragg grating Fabry-Perot cavity is chosen in order to enhance the laser conversion efficiency and suppress the higher-order Stokes waves. The laser reaches the threshold at input power of 35 mW, and the experimental laser conversion efficiency achieves 18% of the input power of 140 mW and does not show higher-order Stokes waves. A photonic crystal fibre BriUouin laser withshorter fibre length and lower threshold is experimentally realized.

  17. Helically twisted photonic crystal fibres

    Science.gov (United States)

    Russell, P. St. J.; Beravat, R.; Wong, G. K. L.

    2017-02-01

    Recent theoretical and experimental work on helically twisted photonic crystal fibres (PCFs) is reviewed. Helical Bloch theory is introduced, including a new formalism based on the tight-binding approximation. It is used to explore and explain a variety of unusual effects that appear in a range of different twisted PCFs, including fibres with a single core and fibres with N cores arranged in a ring around the fibre axis. We discuss a new kind of birefringence that causes the propagation constants of left- and right-spinning optical vortices to be non-degenerate for the same order of orbital angular momentum (OAM). Topological effects, arising from the twisted periodic `space', cause light to spiral around the fibre axis, with fascinating consequences, including the appearance of dips in the transmission spectrum and low loss guidance in coreless PCF. Discussing twisted fibres with a single off-axis core, we report that optical activity in a PCF is opposite in sign to that seen in a step-index fibre. Fabrication techniques are briefly described and emerging applications reviewed. The analytical results of helical Bloch theory are verified by an extensive series of `numerical experiments' based on finite-element solutions of Maxwell's equations in a helicoidal frame. This article is part of the themed issue 'Optical orbital angular momentum'.

  18. Helically twisted photonic crystal fibres

    Science.gov (United States)

    Beravat, R.; Wong, G. K. L.

    2017-01-01

    Recent theoretical and experimental work on helically twisted photonic crystal fibres (PCFs) is reviewed. Helical Bloch theory is introduced, including a new formalism based on the tight-binding approximation. It is used to explore and explain a variety of unusual effects that appear in a range of different twisted PCFs, including fibres with a single core and fibres with N cores arranged in a ring around the fibre axis. We discuss a new kind of birefringence that causes the propagation constants of left- and right-spinning optical vortices to be non-degenerate for the same order of orbital angular momentum (OAM). Topological effects, arising from the twisted periodic ‘space’, cause light to spiral around the fibre axis, with fascinating consequences, including the appearance of dips in the transmission spectrum and low loss guidance in coreless PCF. Discussing twisted fibres with a single off-axis core, we report that optical activity in a PCF is opposite in sign to that seen in a step-index fibre. Fabrication techniques are briefly described and emerging applications reviewed. The analytical results of helical Bloch theory are verified by an extensive series of ‘numerical experiments’ based on finite-element solutions of Maxwell's equations in a helicoidal frame. This article is part of the themed issue ‘Optical orbital angular momentum’. PMID:28069771

  19. General demonstration of principal states of polarization and real-time monitoring of polarization mode dispersion in optical fibres

    Institute of Scientific and Technical Information of China (English)

    Dong Hui; Wu Chong-Qing; Fu Song-Nian

    2004-01-01

    We investigated the general properties of polarization effects in optical fibres and demonstrated the existence of socalled principal states of polarization (PSP), which mean the fixed points in mathematics, in different polarization effects,such as birefringence and polarization mode dispersion, by using fixed point theory. Furthermore, a time evolution vector is defined to describe the time evolution of polarization state in optical fibres, which is used to investigate the time evolution of polarization mode dispersion vector (PDV), including differential group delay and PSP. The experimentalresults of real-time monitoring of PDV by using this method are reported. To our knowledge, this is the first report on monitoring PSP evolution in optical fibres.

  20. Effect of heat treatment on absorption and fluorescence properties of PbS-doped silica optical fibre

    Science.gov (United States)

    Qin, Fu; Dong, Yanhua; Wen, Jianxiang; Pang, Fufei; Luo, Yanhua; Peng, Gang-Ding; Chen, Zhenyi; Wang, Tingyun

    2017-02-01

    The effect of heat treatment on the optical properties of a PbS-doped silica optical fibre was investigated. The experimental results showed that the absorption peak of the fibre red shifted from 1032 to 1133 nm when the heat treatment temperatures were carried out at 900, 950, 1000, and 1100 °C for 1 h, respectively. At the same time, when the heat treatment at 900 °C was carried out for 2, 5, 10, 20, and 40 h, the absorption spectra of the fibre showed a red shift from 1074 to 1143 nm. In addition, the intensity of the absorption peak increased from 0.258 to 1.384 dB/m and the full width at half maximum (FWHM) became narrower (from 130 to 50 nm) as the heat treatment proceeded. Moreover, the photoluminescence (PL) intensity in the wavelength range of 1100-1500 nm decreased with an increase in the heat treatment temperature. The theoretical analysis, using an effective mass method, showed that the effective band gap energy and average size of the lead sulphide (PbS) quantum dots (QDs) in the silica fibre core varied from 1.199 to 1.083 eV and from 4.28 to 4.81 nm, respectively. The results indicate that the size of the PbS QDs present in the silica fibre core could be controlled by a proper heat treatment, which is of great interest in optical fibre amplifiers and other fibre optic devices.

  1. Optical cavity fibre sensor for detection of microcystin-LR in water

    Science.gov (United States)

    Queirós, Raquel B.; Silva, S. O.; Sales, M. G. F.; Noronha, J. P.; Frazão, O.; Jorge, P. A. S.; Aguilar, G. G.

    2010-09-01

    The deterioration of water quality by Cyanobacteria causes outbreaks and epidemics associated with harmful diseases in Humans and animals because of the released toxins. Microcystin-LR (mcyst) is one of the most widely studied hepatotoxin and World Health Organization recommends a maximum value of 1 μg L-1 of mcyst in drinking-water. Therefore, there is a great demand for remote, real-time sensing techniques to detect and quantify the presence of mcyst. In this work a Fabry-Perot sensing probe based on a fibre tip coated with a mcyst sensitive thin film is presented. Highly specific recognition membranes, using sol-gel based Molecular Imprinted Polymers (MIPs), were developed to quantify microcystins in water, showing great potential in the analysis of this kind of samples. The fibre Fabry-Perot MIP sensor shows a linear response to mcyst concentration with a sensitivity of -13.2 +/-} 0.4 nm L μg-1.

  2. 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

  3. 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.

  4. 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.

  5. Determination of setting expansion of dental materials using fibre optical sensing

    Science.gov (United States)

    Milczewski, M. S.; da Silva, J. C. C.; Abe, I.; Carvalho, L.; Nogueira, R. N.; Paterno, A. S.; Kalinowski, H. J.; Pinto, J. L.

    2006-05-01

    The use of fibre Bragg grating sensors to study dental materials like resin-based composite and gypsum products is reported. Two commercially available composite resins and three types of gypsum products were tested in order to determine polymerization contraction and setting expansion. Temperature and strain evolution during the hardening phase of the material were also obtained. The presented technique can be a good tool for dentists in order to better manipulate a material and predict how it will behave in vivo.

  6. Uranyl-specific binding at a functionalised interface: a chemophotonic fibre optic sensor platform.

    Science.gov (United States)

    Hayes, Neil W; Tremlett, Clare J; Melfi, Patricia J; Sessler, Jonathon D; Shaw, Andrew M

    2008-05-01

    Detection of radiological materials in the solution phase is restricted by conventional radiation-counting techniques owing to extreme attenuation. Chemical sensing of the resultant radiological species such as uranyl UO(2)(2+) is possible on the surface of a plastic or glass fibre optic. A dihydroxy isoamethryin complex is tethered to the fibre surface which has a large extinction coefficient (119 000 M(-1) cm(-1) at lambda = 439 nm) and changes colour upon binding UO(2)(2+). The spectral changes are greater on the surface than in solution and binding is specific to UO(2)(2+) with small interferences from Gd(3+). Monitoring the spectral response in three detector bands in the red, green and blue enable the optical power change to be measured with sensitivities of 1 mdB, allowing UO(2)(2+) to be detected confidently at 50-100 ppb levels. Real-time kinetic analysis enables discrimination between the target species and possible interferents.

  7. Determination of inorganic elements in animal feeds by NIRS technology and a fibre-optic probe.

    Science.gov (United States)

    González-Martín, Inmaculada; Alvarez-García, Noelia; González-Pérez, Claudio; Villaescusa-García, Virginia

    2006-05-15

    In the present work we study the use of near infra-red spectroscopy (NIRS) technology together with a remote reflectance fibre-optic probe for the analysis of the mineral composition of animal feeds. The method allows immediate control of the feeds without prior sample treatment or destruction through direct application of the fibre-optic probe on the sample. The regression method employed was modified partial least squares (MPLS). The calibration results obtained using forty samples of animal feeds allowed the determination of Fe, Mn, Ca, Na, K, P, Zn and Cu, with a standard error of prediction (SEP(C)) and a correlation coefficient (RSQ) of 0.129 and 0.859 for Fe; 0.175 and 0.816 for Mn; 5.470 and 0.927 for Ca; 2.717 and 0.862 for Na; 4.397 and 0.891 for K; 2.226 and 0.881 for P; 0.153 and 0.764 for Zn, and 0.095 and 0.918 for Cu, respectively. The robustness of the method was checked by applying it to 10 animal feeds samples of unknown mineral composition in the external validation.

  8. A simple optical fibre probe for differentiation between healthy and tumorous tissue

    Science.gov (United States)

    Schartner, Erik P.; Henderson, Matthew R.; Purdey, Malcolm; Monro, Tanya M.; Gill, P. Grantley; Callen, David F.

    2016-11-01

    Incomplete removal of malignant tumours continues to be a significant issue in cancer surgery. It increases the risk of local recurrence and impaired survival, and results in the need for additional surgery with associated attendant costs and morbidity. While pathological methods exist to determine tissue type during surgery, these methods can compromise post-operative pathology, have a lag of minutes to hours before the surgeon receives the results of the tissue analysis and are restricted to excised tissue. In this work we report the development of an optical fibre probe which could find use as an aid for margin detection during surgery. A fluorophore doped polymer coating is deposited on the tip of an optical fibre, which can then be used to record the pH by monitoring the emission spectra from the embedded indicator. The pH values of unknown tissue are measured and compared to healthy tissue, allowing for discrimination between healthy and cancerous tissue. The probe developed here shows strong potential for use during surgery, as the probe design can be readily adapted to a low-cost portable configuration which could find use in the operating theatre. Use of this probe in surgery either on excised or in-vivo tissue has the potential to improve success rates for complete removal of cancers.

  9. Establishment of Ge-doped optical fibres as thermoluminescence dosimeters for brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Issa, Fatma, E-mail: f.issa@surrey.ac.uk [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Department of Radiotherapy, Tripoli Medical Centre (TMC), Tripoli (Libya); Abdul Rahman, A.T. [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); School of Physics and Material Studies, Faculty of Applied Sciences, Universiti Teknologi MARA Malaysia, Campus of Negeri Sembilan, 72000 Kuala Pilah (Malaysia); Hugtenburg, Richard P. [Department of Medical Physics and Clinical Engineering, Abertawe Bro Morgannwg UHB and School of Medicine, Swansea University, Swansea, SA2 8PP (United Kingdom); Bradley, David A. [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Department of Radiological Sciences, King Saud University, P.O. Box 10219, Riyadh 11432 (Saudi Arabia); Nisbet, Andrew [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Department of Medical Physics, Royal Surrey County Hospital NHS Foundation Trust, Guildford, GU2 7XX (United Kingdom)

    2012-07-15

    This study aims to establish the sensitive, {approx}120 {mu}m high spatial resolution, high dynamic range Ge-doped optical fibres as thermoluminescence (TL) dosimeters for brachytherapy dose distribution. This requires investigation to accommodate sensitivity of detection, both for the possibility of short range dose deposition from beta components as well as gamma/x-mediated dose. In-air measurements are made at distances close to radionuclide sources, evaluating the fall off in dose along the transverse axis of {sup 133}Ba and {sup 60}Co radioactive sources, at distances from 2 mm up to 20 mm from their midpoints. Measurements have been compared with Monte Carlo code DOSRZnrc simulations for photon-mediated dose only, agreement being obtained to within 3% and 1% for the {sup 133}Ba and {sup 60}Co sources, respectively. As such, in both cases it is determined that as intended, beta dose has been filtered out by source encapsulation. - Highlights: Black-Right-Pointing-Pointer We seek to establish Ge-doped optical fibres as TLDs for brachytherapy. Black-Right-Pointing-Pointer Dose was evaluated along the central axis of {sup 133}Ba and {sup 60}Co, at 2 mm-20 mm. Black-Right-Pointing-Pointer We verify values using DOSRZnrc Monte Carlo code simulations. Black-Right-Pointing-Pointer Good agreement is between dose measurements and calculation to within 3% and 1%. Black-Right-Pointing-Pointer Methodology is to be used in obtaining doses around {sup 125}I and {sup 192}Ir sources.

  10. Ultra-stable optical frequency dissemination on a multi-access fibre network

    CERN Document Server

    Bercy, Anthony; Pottie, Paul-Eric; Amy-Klein, Anne

    2016-01-01

    We report the dissemination of an ultrastable optical frequency signal to two distant users simultaneously using a branching network. The ultrastable signal is extracted along a main fibre link; it is optically tracked with a narrow-linewidth laser diode, which light is injected in a secondary link. The propagation noise of both links is actively compensated. We implement this scheme with two links of 50-km fibre spools, the extraction being setup at the mid-point of the main link. We show that the extracted signal at the end of the secondary link exhibits fractional frequency instability of 1.4x10-15 at 1-s measurement time, almost equal to the 1.3x10-15 instability of the main link output end. The long-term instabilities are also very similar, at a level of 3-5x10-20 at 3x104-s integration time. We also show that the setting up of this extraction device, or a simpler one, at the main link input, can test the proper functioning of the noise rejection on this main link. This work is a significant step towards...

  11. Photonic Crystal Fibre SERS Sensors Based on Silver Nanoparticle Colloid

    Institute of Scientific and Technical Information of China (English)

    XIE Zhi-Guo; LU Yong-Hua; WANG Pei; LIN Kai-Qun; YAN Jie; MING Hai

    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 maes-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.

  12. A Study on Protection of Cables by Solkor Differential Protection Relay with Fibre Optic Pilot Wireor Metallic Pilot Wire

    Directory of Open Access Journals (Sweden)

    Ahmed Rashad .E. Bakr

    2015-02-01

    Full Text Available This paper intends to briefly compare the protection of buried three phase high voltage cable with Solkordifferential protection relay using metallic pilot wires orfibre optic pilot wires. Dielectric property of the fiber optic provides complete electrical isolation as well as interference free signaling. This provides total immunity from GPR (ground potential rise, longitudinal induction, and differential mode noise coupling andhigh-voltage hazards to personnel safety. So Fibre optic provides great advantage for Solkor differential protection relaying.

  13. 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...

  14. Potential clinical utility of a fibre optic-coupled dosemeter for dose measurements in diagnostic radiology.

    Science.gov (United States)

    Jones, A Kyle; Hintenlang, David

    2008-01-01

    Many types of dosemeters have been investigated for absorbed dose measurements in diagnostic radiology, including ionisation chambers, metal-oxide semiconductor field-effect transistor dosemeters, thermoluminescent dosemeters, optically stimulated luminescence detectors, film and diodes. Each of the aforementioned dosemeters suffers from a critical limitation, either the need to interrogate, or read, the dosemeter to retrieve dose information or large size to achieve adequate sensitivity. This work presents an evaluation of a fibre optic-coupled dosemeter (FOCD) for use in diagnostic radiology dose measurement. This dosemeter is small, tissue-equivalent and capable of providing true real-time dose information. The FOCD has been evaluated for dose linearity, angular dependence, sensitivity and energy dependence at energies, beam qualities and beam quantities relevant to diagnostic radiology. The FOCD displayed excellent dose linearity and high sensitivity, while exhibiting minimal angular dependence of response. However, the dosemeter does exhibit positive energy dependence, and is subject to attenuation of response when bent.

  15. 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.

  16. 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.

  17. Analysis of concrete foundation piles using structure-integrated fibre-optic sensors; Strukturanalyse von Betonpfaehlen durch eingebettete faseroptische Sensoren

    Energy Technology Data Exchange (ETDEWEB)

    Schallert, Matthias [Gesellschaft fuer Schwingungsuntersuchungen und Dynamische Pruefmethoden (GSP) mbH, Mannheim (Germany); Hofmann, Detlef; Habel, Wolfgang R. [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

    2008-07-01

    Reinforced concrete piles are often used for structures on non-sufficiently bearing soil areas. Assessment of bearing capacity and bearing behaviour of large concrete piles remains a difficult task under specific soil conditions and pile geometries. Usually static and dynamic pile tests are carried out for quality assurance. From dynamic measurements taken only from the pile head, the bearing behaviour and structural integrity can be derived using the one-dimensional theory of wave propagation. More precise information about the pile features can be achieved by highly resolving fibre-optic sensors based on Fabry-Perot technology, distributed over several locations along the pile length. Small scale piles and real driven piles have been tested. This paper describes the sensor, the sensor installation, and experimental results of tests in laboratory as well as test results for recording the wave propagation in the small scale piles. (orig.)

  18. Advances in infrared and imaging fibres for astronomical instrumentation

    CERN Document Server

    Haynes, R; Marcel, J; Jovanovic, N; Haynes, Roger; Namara, Pam Mc; Marcel, Jackie; Jovanovic, Nemanja

    2006-01-01

    Optical fibres have already played a huge part in ground based astronomical instrumentation, however, with the revolution in photonics currently taking place new fibre technologies and integrated optical devices are likely to have a profound impact on the way we manipulate light in the future. The Anglo-Australian Observatory, along with partners at the Optical Fibre Technology Centre of the University of Sydney, is investigating some of the developing technologies as part of our Astrophotonics programme. In this paper we discuss the advances that have been made with infrared transmitting fibre, both conventional and microstructured, in particular those based on flouride glasses. Flouride glasses have a particularly wide transparent region from the UV through to around 7um, whereas silica fibres, commonly used in astronomy, only transmit out to about 2um. We discuss the impact of advances in fibre manufacture that have greatly improved the optical, chemical resistance and physical properties of the flouride f...

  19. Ultra-high and persistent optical depths of caesium in Kagom\\'e-type hollow-core photonic crystal fibres

    CERN Document Server

    Kaczmarek, Krzysztof T; Sprague, Michael R; Kolthammer, W Steven; Feizpour, Amir; Ledingham, Patrick M; Brecht, Benjamin; Poem, Eilon; Abdolvand, Amir; Russell, Philip St J; Walmsley, Ian A; Nunn, Joshua

    2015-01-01

    Alkali-filled hollow-core fibres are a promising medium for investigating light-matter interactions, especially at the single-photon level, due to the tight confinement of light and high optical depths achievable by light-induced atomic desorption. However, until now these large alkali vapour densities could only be generated for seconds at most once per day, severely limiting the practicality of the technology. Here we report the generation of highest observed transient ($>10^5$ for minutes) and highest observed persistent (>2000 for hours) optical depths of alkali vapours in hollow-core fibres to date, using a caesium-filled Kagom\\'e-type hollow-core photonic crystal fibre. Our results pave the way to light-matter interaction experiments in confined geometries requiring long operation times and large atomic number densities, such as single-photon-level light-matter interaction experiments and fundamental investigations of hot dense atomic gases.

  20. 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…

  1. Experimental Investigation of Pump-to-Signal Noise Transfer in One-Pump Phase Insensitive Fibre Optic Parametric Amplifiers

    DEFF Research Database (Denmark)

    Cristofori, Valentina; Lund-Hansen, Toke; Peucheret, Christophe

    2011-01-01

    This paper presents a detailed experimental characterization of the relative intensity noise (RIN) transferred from the pump to the signal in one-pump phase insensitive fibre optic parametric amplifiers. We extend an existing experimental and theoretical work towards higher frequencies, showing...

  2. Review of doped silica glass optical fibre: their TL properties and potential applications in radiation therapy dosimetry.

    Science.gov (United States)

    Bradley, D A; Hugtenburg, R P; Nisbet, A; Abdul Rahman, Ahmad Taufek; Issa, Fatma; Mohd Noor, Noramaliza; Alalawi, Amani

    2012-12-01

    Review is made of dosimetric studies of Ge-doped SiO(2) telecommunication fibre as a 1-D thermoluminescence (TL) system for therapeutic applications. To-date, the response of these fibres has been investigated for UV sources, superficial X-ray beam therapy facilities, a synchrotron microbeam facility, electron linear accelerators, protons, neutrons and alpha particles, covering the energy range from a few eV to several MeV. Dosimetric characteristics include, reproducibility, fading, dose response, reciprocity between TL yield and dose-rate and energy dependence. The fibres produce a flat response to fixed photon and electron doses to within better than 3% of the mean TL distribution. Irradiated Ge-doped SiO(2) optical fibres show limited signal fading, with an average loss of TL signal of ~0.4% per day. In terms of dose response, Ge-doped SiO(2) optical fibres have been shown to provide linearity to x and electron doses, from a fraction of 1 Gy up to 2 kGy. The dosimeters have also been used in measuring photoelectron generation from iodinated contrast media; TL yields being some 60% greater in the presence of iodine than in its absence. The review is accompanied by previously unpublished data.

  3. Distributed fibre optic temperature measurement system for the safety monitoring of the next generation of large nuclear facilities

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Fernandez, Alberto; Brichard, Benoit [SCK-CEN, Belgian Nuclear Research Center (Belgium); Hartog, Arthur H.; Hughes, Paul [SENSA, a Schlumberger Company (United Kingdom)

    2006-07-01

    The use of optical fibre distributed sensors for temperature sensing is a powerful way of monitoring, quasi simultaneously, thousands of points avoiding the requirement of optimum positioning of discrete temperature sensors. Their range of applications is rapidly expanding in the industry, and nowadays this fibre optic sensing technology is mature for industrial applications such as fire detection inside buildings and tunnels, process vessel monitoring, leak detection in cryogenic storage vessels (liquid natural gas (LNG), ammonia, ethylene) or oil wells and the measurement of energy cable thermal distribution for the power supply industry. These applications rely on the well known immunity of fibre optic sensors to electromagnetic interference and the ability of fibre sensors to be operated in hazardous environments. The nuclear industry shows a growing interest for the possibilities offered for temperature sensing applications. Fibre optic sensing technology could be considered as an alternative to classical measurements techniques in a wide range of applications. The potential of distributed temperature measurements for the monitoring of large nuclear infrastructures such as reactor containment buildings, nuclear waste repositories and reactor primary circuitry have already been shown. However, a major problem in the application of optical fibres in nuclear environments is the presence of ionizing radiation fields that induce an increase of the optical fibre attenuation. This radiation-induced degradation of the measurement signal could be critical since most commercially available distributed temperature sensors derive the temperature profile from the measurement of the Raman backscattered light intensity along the fibre, using optical time domain reflectometry techniques. The Raman signal comprises two elements: the Stokes and anti-Stokes lines. The longer wavelength Stokes line is only weakly temperature sensitive but the intensity of the backscattered light

  4. Prospective Study on Retinal Nerve Fibre Layer Thickness Changes in Isolated Unilateral Retrobulbar Optic Neuritis

    Directory of Open Access Journals (Sweden)

    Gordon S. K. Yau

    2013-01-01

    Full Text Available Purpose. To investigate the retinal nerve fibre layer (RNFL thickness after unilateral acute optic neuritis using optical coherence tomography (OCT. Patients and Methods. This prospective cohort study recruited consecutive patients with a first episode of isolated, unilateral acute optic neuritis. RNFL thickness and visual acuity (VA of the attack and normal fellow eye were measured at presentation and 3 months in both the treatment and nontreatment groups. Results. 11 subjects received systemic steroids and 9 were treated conservatively. The baseline RNFL thickness was similar in the attack and fellow eye (P≥0.4. At 3 months, the attack eye had a thinner temporal (P=0.02 and average (P=0.05 RNFL compared to the fellow eye. At 3 months, the attack eye had significant RNFL thinning in the 4 quadrants and average thickness (P≤0.0002 compared to baseline. The RNFL thickness between the treatment and nontreatment groups was similar at baseline and 3 months (P≥0.1. Treatment offered better VA at 3 months (0.1 ± 0.2 versus 0.3 ± 0.2 LogMAR, P=0.04. Conclusion. Generalized RNFL thinning occurred at 3 months after a first episode of acute optic neuritis most significantly in the temporal quadrant and average thickness. Visual improvement with treatment was independent of RNFL thickness.

  5. Fibre Optic Laser Doppler Anemometry, The Potential For Measurements In Man.

    Science.gov (United States)

    Kilpatrick, Walker D.

    1984-10-01

    Fibre optic laser Doppler anemometry (FOLDA) is a useful technique for in vitro studies but has yet to be used successfully for the measurement of intravascular velocity in man. Some reasons for this are: 1. The difficulty of locating the position of the fibre within the vessel. 2. Lack of knowledge of the precise velocity profile across the vessel. 3. The effects of flow perturbation at the tip of the probe. These problems have been assessed using a FOLDA system developed in our laboratory. Three dimensional velocity profiles of blood flowing in arteries with and without stenoses have been plotted at different rates of flow. The results show that the parabolic profile of fully developed laminar flow is flattened in an arterial stenosis and the degree of flattening increases as flow increases. This means the relationship of the flow and velocity is nonlinear. Any use of FOLDA to assess vessel dimension must take this into account. The position of the fibre in the vessel can only be adequately controlled in in-vitro studies. The region of measurement is only 50 μm diameter and must be at the position of the peak velocity to enable quantitative measurement. Thus the technique is useful in humans only when there is a flat velocity profile such as in the coronary sinus. The relationship between coronary sinus flow and FOLDA velocity is linear in experimental animals. The current FOLDA system has a limited range of projection into the blood stream. The velocity is not linearly related to blood flow when the direction of flow is the same as the projected light, probably due to flow perturbation at the fibre tip. This means that a probe introduced into a coronary artey would not measure linear flow however a probe introduced against the flow could be used to assess the severity of peripheral arterial stenoses. To measure flow across a stenoses before and after angioplasty is possible but requires a method of obtaining an average spatial velocity before it is practicable.

  6. Toughening and healing of continuous fibre reinforced composites with bis-maleimide based pre-pregs

    Science.gov (United States)

    Kostopoulos, V.; Kotrotsos, A.; Tsantzalis, S.; Tsokanas, P.; Christopoulos, A. C.; Loutas, T.

    2016-08-01

    Unidirectional (UD) pre-pregs containing self-healing materials based on Diels-Alder reaction bis-maleimide (BMI) polymers were successfully incorporated on the mid-plane of UD carbon fibre reinforced polymers. The fracture toughness of these composites and the introduced healing capability were measured under mode I loading. The interlaminar fracture toughness was enhanced considerably, since the maximum load (P max) of the modified composite increased approximately 1.5 times and the mode I fracture energy (G IC) displayed a significant increase of almost 3.5 times when compared to the reference composites. Furthermore the modified composites displayed a healing efficiency (HE) value of about 30% for P max and 20% for G IC after the first healing, appearing to be an almost stable behaviour after the third healing cycle. The HE displayed a decrease of 20% and 15% for P max and G IC values, respectively, after the fifth healing cycle. During the tests, the monitored acoustic emission (AE) activity of the samples showed that there is no significant difference due to the presence of BMI polymer in terms of AE hits. Moreover, optical microscopy not only showed that the epoxy matrix at the interface is partly infiltrated by the BMI polymer, but it also revealed the presence of pulled out fibres at the fractured surface, indicating ductile behaviour.

  7. 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.

    2015-05-01

    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.

  8. 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.

  9. 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

  10. 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

    2016-06-24

    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.

  11. 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.

  12. 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.

  13. 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.

  14. Correlation of optic neuritis and retinal nerve fibre thickness using optical coherence tomography in a cohort of multiple sclerosis patients

    Directory of Open Access Journals (Sweden)

    Izanne Roos

    2016-03-01

    Full Text Available Background: Optical coherence tomography (OCT is a fast, non-invasive imaging technology that produces 3D, high-resolution images of the retina. Direct visualisation of the retina allows a unique opportunity to study the effects of multiple sclerosis (MS-associated neurodegeneration on retinal ganglion cells as well as effects of retrobulbar demyelination on axonal and retinal architecture through measurement of retinal nerve fibre layer (RNFL thickness and total macular volume (TMV. These findings are clinically important as axonal loss is irreversible and correlates with disability.Aim: To determine the role and usefulness of OCT in a local cohort of MS patients.Setting: Neurology Clinic, Inkosi Albert Luthuli Central Hospital, KwaZulu-Natal, South Africa.Methods: Nineteen patients with MS currently being treated with interferon β-1b underwent OCT examination of both eyes. RNFL thickness and macular volume were measured and correlated with clinical disease characteristics, history of optic neuritis and level of disability.Results: Mean RNFL thickness was 77.3 μm with no significant difference in mean RNFL in eyes with a history of optic neuritis (ON and those without (p = 0.4. Eyes with a history of ON did, however, have significantly thinner RNFL compared with the contralateral eye (p = 0.04. Despite a strong correlation between TMV and RNFL (p = 0.001, a subset of patients with normal RNFL had TMV that was less than 1% of what was expected. There was no correlation between RNFL and disability scores.Conclusion: OCT enables a direct axonal ‘optical biopsy’, for monitoring disease progression and treatment response in MS. RNFL thinning occurs independently of a history of optic neuritis and may represent a chronic optic neuropathy in patients with MS.Keywords: Multiple sclerosis; optical coherence tomography

  15. Moiré Fibre Bragg Grating Written on Strained Fibres

    Institute of Scientific and Technical Information of China (English)

    孙磊; 冯新焕; 刘艳格; 张伟刚; 袁树忠; 开桂云; 董孝义

    2004-01-01

    Moiré fibre Bragg gratings are made in a single mode fibre and a polarization-maintaining fibre respectively, using an excimer KrF laser and a phase mask. Two gratings are written at the same location of the optical fibre. The wavelength spacing can be finely tuned from 0 to 1.86nm by straining the optical fibre during UV illumination.

  16. Equal-Amplitude Optical Pulse Generation from a Rational Harmonic Mode-Locked Fibre Laser

    Institute of Scientific and Technical Information of China (English)

    FENG Xin-Huan; YUAN Shu-Zhong; LI Yao; LIU Yan-Ge; KAI Gui-Yun; DONG Xiao-Yi

    2004-01-01

    A simple technique for the generation of equal-amplitude high repetition rate pulses from a rational harmonic mode-locked fibre ring laser is demonstrated. The principle is based on the combination of the nonlinear characteristics of the modulator and the effect of rational harmonic mode-locking. The two sources act on each other and the integrated effect eventually leads to the pulse amplitude-equalization. We obtain amplitude-equalized short pulses up to the fifth-order rational harmonic mode-locking with an optimum bias level and modulation depth of the modulator, which demonstrates the efficiency of this method.

  17. 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}}.

  18. SiC-based ceramic fibres : thermal stability and oxidation behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Greck, O.; Viricelle, J.P.; Bahloul-Hourlier, D.; Goursat, P. [Limoges Univ. (France). LMCTS/LCN; Dalbin, M.; Thomin, S. [CEAT, Toulouse (France); Flank, A.M. [LURE, Centre Univ., Orsay (France)

    1997-12-31

    The thermal stability of three commercial SiC-based fibres (Tyranno Lox M and Lox E, Hi-Nicalon) has been studied through their gaseous release and density changes followed by mass spectrometry and thermal expansion experiments. An axial shrinkage of about 0.8% has been measured in neutral and oxidizing atmosphere, at temperatures corresponding to the final pyrolysis treatment during the fibre processing (1200 C for Lox M and Lox E, 1400 C for Hi-Nicalon). This shrinkage is concommited with residual hydrogen removal for Tyranno fibres. In oxidizing conditions, the release of hydrogen results in water vapour formation which enhances the oxidation kinetics. (orig.) 5 refs.

  19. Light and gas confinement in hollow-core photonic crystal fibre based photonic microcells

    DEFF Research Database (Denmark)

    Benabid, F.; Roberts, John; Couny, F.;

    2009-01-01

    optical waveguide guidance. For the second type of fibre, which can guide over a broad wavelength range, we examine the nature of the inhibited coupling. We describe a technique for the fabrication of photonic microcells that can accommodate vacuum pressures, and we finish by showing the latest results...

  20. Fibrous Polymeric Composites Based on Alginate Fibres and Fibres Made of Poly-ε-caprolactone and Dibutyryl Chitin for Use in Regenerative Medicine

    Directory of Open Access Journals (Sweden)

    Elżbieta Menaszek

    2013-03-01

    Full Text Available This work concerns the production of fibrous composite materials based on biodegradable polymers such as alginate, dibutyryl chitin (DBC and poly-ε-caprolactone (PCL. For the production of fibres from these polymers, various spinning methods were used in order to obtain composite materials of different composition and structure. In the case of alginate fibres containing the nanoadditive tricalcium phosphate (TCP, the traditional method of forming fibres wet from solution was used. However in the case of the other two polymers the electrospinning method was used. Two model systems were tested for biocompatibility. The physicochemical and basic biological tests carried out show that the submicron fibres produced using PCL and DBC have good biocompatibility. The proposed hybrid systems composed of micrometric fibres (zinc and calcium alginates containing TCP and submicron fibres (DBC and PCL meet the requirements of regenerative medicine. The biomimetic fibre system, the presence of TCP nanoadditive, and the use of polymers with different resorption times provide a framework with specific properties on which bone cells are able to settle and proliferate.

  1. 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...

  2. Deep tissue volume imaging of birefringence through fibre-optic needle probes for the delineation of breast tumour

    Science.gov (United States)

    Villiger, Martin; Lorenser, Dirk; McLaughlin, Robert A.; Quirk, Bryden C.; Kirk, Rodney W.; Bouma, Brett E.; Sampson, David D.

    2016-07-01

    Identifying tumour margins during breast-conserving surgeries is a persistent challenge. We have previously developed miniature needle probes that could enable intraoperative volume imaging with optical coherence tomography. In many situations, however, scattering contrast alone is insufficient to clearly identify and delineate malignant regions. Additional polarization-sensitive measurements provide the means to assess birefringence, which is elevated in oriented collagen fibres and may offer an intrinsic biomarker to differentiate tumour from benign tissue. Here, we performed polarization-sensitive optical coherence tomography through miniature imaging needles and developed an algorithm to efficiently reconstruct images of the depth-resolved tissue birefringence free of artefacts. First ex vivo imaging of breast tumour samples revealed excellent contrast between lowly birefringent malignant regions, and stromal tissue, which is rich in oriented collagen and exhibits higher birefringence, as confirmed with co-located histology. The ability to clearly differentiate between tumour and uninvolved stroma based on intrinsic contrast could prove decisive for the intraoperative assessment of tumour margins.

  3. Multi-fibre optical spectroscopy of low-mass stars and brown dwarfs in Upper Sco

    CERN Document Server

    Lodieu, N; Hambly, N C

    2011-01-01

    We have obtained multi-fibre intermediate-resolution optical spectroscopy of 94 photometric and proper motion selected low-mass star and brown dwarf candidates in Upper Sco with AAT/AAOmega. We have estimated the spectral types and measured the equivalent widths of youth and gravity diagnostic features to confirm the spectroscopic membership of about 95% of the candidates extracted from 6.5 square degrees in Upper Sco. We also detect lithium in the spectra with the highest signal-to-noise, consolidating our conclusions about their youth. Furthermore, we derive an estimate of our selections using spectroscopic data obtained for a large number of stars falling into the instrument's field-of-view. We have estimated the effective temperatures and masses for each new spectroscopic member using the latest evolutionary models available for low-mass stars and brown dwarfs. Combining the current optical spectroscopy presented here with near-infrared spectroscopy obtained for the faintest photometric candidates, we con...

  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. FIBRE FLAX PREPLANT TREATMENT BASED ON SEED PELLETING AND ELECTROTECHNICS

    Directory of Open Access Journals (Sweden)

    Spiridonov A. B.

    2013-10-01

    Full Text Available The method of fibre flax preplant seed treatment that includes pelleting in bionanosuspension and influence of electrophysical fields on the pellet is described in the article. Due to given treatment technology it is possible to increase the crop capacity and engineering performance of the flax production

  6. 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...

  7. 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

    impact categories, than the conventional materials. This observation may seem contra-intuitive (i.e. most people would expect the bio-based to be most sustainable), but is primarily caused by the fact that the resin demand of biobased reinforcement materials is by far larger than that of conventional...... reinforcement materials. Since the environmental burden of the resin in addition is comparable to that of the fibres (especially in terms human health related impacts), the higher resin demand counterbalances the environmental sustainability improvements, obtained with the application of natural fibres....... turbines have therefore partially been focused on substitution of conventional fibre materials with bio-fibres assuming that this substitution was in the better for the environment and human health. The major question is if this material substitution, taking into account a multitude of environmental impact...

  8. Mineral fibres: correlation between oxidising surface activity and DNA base hydroxylation.

    Science.gov (United States)

    Nejjari, A; Fournier, J; Pezerat, H; Leanderson, P

    1993-06-01

    In relation to their potential genotoxic properties, the ability of inorganic particles to induce activated species of oxygen with strong oxidative properties can be studied by various methods. In this study the oxidative surface properties of 10 different natural and synthetic mineral fibres were investigated by: (1) an electron paramagnetic resonance technique in which formate was used to trap oxidative species; and (2) a high performance liquid chromatography (HPLC) based method in which deoxyguanosine was used as a trapping agent and the formation of 8-hydroxy-deoxyguanosine (8 OHdG) was analysed. Ground iron-containing fibres such as crocidolite and amosite were the most reactive, whereas fibres without iron--for example, ceramic fibres, xonotlite, and Tismo L--were completely inactive. A good correlation was found when the results from the two methods were compared (r = 0.86).

  9. 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

    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......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...... turbines have therefore partially been focused on substitution of conventional fibre materials with bio-fibres assuming that this substitution was in the better for the environment and human health. The major question is if this material substitution, taking into account a multitude of environmental impact...

  10. Random distributed feedback fibre lasers

    Science.gov (United States)

    Turitsyn, Sergei K.; Babin, Sergey A.; Churkin, Dmitry V.; Vatnik, Ilya D.; Nikulin, Maxim; Podivilov, Evgenii V.

    2014-09-01

    of a stationary near-Gaussian beam with a narrow spectrum. A random distributed feedback fibre laser has efficiency and performance that are comparable to and even exceed those of similar conventional fibre lasers. The key features of the generated radiation of random distributed feedback fibre lasers include: a stationary narrow-band continuous modeless spectrum that is free of mode competition, nonlinear power broadening, and an output beam with a Gaussian profile in the fundamental transverse mode (generated both in single mode and multi-mode fibres). This review presents the current status of research in the field of random fibre lasers and shows their potential and perspectives. We start with an introductory overview of conventional distributed feedback lasers and traditional random lasers to set the stage for discussion of random fibre lasers. We then present a theoretical analysis and experimental studies of various random fibre laser configurations, including widely tunable, multi-wavelength, narrow-band generation, and random fibre lasers operating in different spectral bands in the 1-1.6 μm range. Then we discuss existing and future applications of random fibre lasers, including telecommunication and distributed long reach sensor systems. A theoretical description of random lasers is very challenging and is strongly linked with the theory of disordered systems and kinetic theory. We outline two key models governing the generation of random fibre lasers: the average power balance model and the nonlinear Schrödinger equation based model. Recently invented random distributed feedback fibre lasers represent a new and exciting field of research that brings together such diverse areas of science as laser physics, the theory of disordered systems, fibre optics and nonlinear science. Stable random generation in optical fibre opens up new possibilities for research on wave transport and localization in disordered media. We hope that this review will provide

  11. 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)

  12. Fibre optics wavemeters calibration using a self-referenced optical frequency comb

    Science.gov (United States)

    Galindo-Santos, J.; Velasco, A. V.; Corredera, P.

    2015-01-01

    Self-referenced optical frequency combs enable the measurement of optical frequencies with a very high accuracy, achieving uncertainties close to the atomic clock used as reference (CSIC and its application to the calibration of two wavemeters in the 1.5 μm optical communication window. Calibration uncertainties down to 12 MHz and 59 MHz were obtained, respectively, for each of the devices. Furthermore, the long-term behaviour of the higher resolution wavemeter was studied during a 750 h period of sustained operation, exhibiting a dispersion in the measurements of 7.72 MHz. Temperature dependence of the device was analysed, enabling to further reduce dispersion down to a 2.15 MHz range, with no significant temporal deviations.

  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. Research on detecting heterogeneous fibre from cotton based on linear CCD camera

    Science.gov (United States)

    Zhang, Xian-bin; Cao, Bing; Zhang, Xin-peng; Shi, Wei

    2009-07-01

    The heterogeneous fibre in cotton make a great impact on production of cotton textile, it will have a bad effect on the quality of product, thereby affect economic benefits and market competitive ability of corporation. So the detecting and eliminating of heterogeneous fibre is particular important to improve machining technics of cotton, advance the quality of cotton textile and reduce production cost. There are favorable market value and future development for this technology. An optical detecting system obtains the widespread application. In this system, we use a linear CCD camera to scan the running cotton, then the video signals are put into computer and processed according to the difference of grayscale, if there is heterogeneous fibre in cotton, the computer will send an order to drive the gas nozzle to eliminate the heterogeneous fibre. In the paper, we adopt monochrome LED array as the new detecting light source, it's lamp flicker, stability of luminous intensity, lumens depreciation and useful life are all superior to fluorescence light. We analyse the reflection spectrum of cotton and various heterogeneous fibre first, then select appropriate frequency of the light source, we finally adopt violet LED array as the new detecting light source. The whole hardware structure and software design are introduced in this paper.

  15. Development and characterization of a hydrophobic treatment for jute fibres based on zinc oxide nanoparticles and a fatty acid

    Science.gov (United States)

    Arfaoui, M. A.; Dolez, P. I.; Dubé, M.; David, É.

    2017-03-01

    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. Introduction of fibre-optic technology in an opencast lignite mine; Einfuehrung von LWL-Technik in einem Braunkohlentagebau

    Energy Technology Data Exchange (ETDEWEB)

    Paus, K.H. [RWE Power AG, Ressort Braunkohlenbergbau/Veredlung, Technikzentrum Tagebaue/HW, Elektrotechnik und technische Vergabe PDV, Kommunikationsanlagen (PBZ-KK), Frechen (Germany); Hehlert, H.A. [RWE Power AG, Ressort Braunkohlenbergbau/Veredlung, Technikzentrum Tagebaue/HW, Elektrotechnik und technische Vergabe Foerderanlagen (PBZ-KP), Frechen (Germany); Andres, M. [RWE Power AG, Ressort Braunkohlenbergbau/Veredlung, Tagebau Hambach, Infrastruktur Prozessdatenverarbeitung (PBH-IP), Niederzier (Germany)

    2006-06-15

    The introduction of fibre-optic technology for the communications infrastructure in our opencast mines entailed the envisaged improvements in automation and operations management. A motivated project team prepared to face new technologies, adopt and use them in day-to-day operations and optimize them has helped sensitive fibre-optic technology to stand the 'acid test' of opencast mine operations. The concepts and operating equipment developed within the scope of the pilot project in the Hambach mine have meanwhile become a standard applied in all RWE Power mines. The whole Garzweiler II mine, for example, has been erected on the basis of these standards. And the upcoming new installation of the belt conveyors in the Inden II mine will be executed in line with these standards as well. (orig.)

  17. Saturation Effect on Pump-to-Signal Intensity Modulation Transfer in Single-Pump Phase-Insensitive Fibre Optic Parametric Amplifiers

    DEFF Research Database (Denmark)

    Cristofori, Valentina; Lali-Dastjerdi, Zohreh; Lund-Hansen, Toke

    2011-01-01

    A numerical and experimental characterization of how signal gain saturation affects the transfer of the intensity modulation of the pump to the signal in single-pump phaseinsensitive fibre optic parametric amplifiers is presented.......A numerical and experimental characterization of how signal gain saturation affects the transfer of the intensity modulation of the pump to the signal in single-pump phaseinsensitive fibre optic parametric amplifiers is presented....

  18. 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....

  19. Small Amplitude Solitons in the Higher-Order Nonlinear Schr(o)dinger Equation in an Optical Fibre

    Institute of Scientific and Technical Information of China (English)

    王凤姣; 唐翌

    2003-01-01

    By taking advantage of the approximate approach of small amplitude soliton, we study the higher-order nonlinear Schrodinger equation in an optical fibre. Our results show that the bright and dark solitons of small amplitude can appear on the background of a continuous wave in normal dispersion regime or in anomalous dispersion regime simultaneously due to the higher-order effects. Interesting connection between the higher-order nonlinear Schrodinger equation and the Korteweg-de Vries equation is also demonstrated.

  20. Repositioning a displaced tracheostomy tube with an Aintree intubation catheter mounted on a fibre-optic bronchoscope.

    Science.gov (United States)

    Rajendram, R; McGuire, N

    2006-10-01

    Although tracheostomy tube displacement is uncommon, the management is often difficult and the associated mortality is high. It is important to ensure that the airway is secure and then either replace or reposition the tracheostomy tube. This case report describes the use of an Aintree intubation catheter (C-CAE-19.0-56-AIC, William Cook Europe, Denmark) mounted on an intubating fibre-optic bronchoscope (11302BD1, Karl Storz Endoskope, Germany) to reposition a partially displaced tracheostomy tube.

  1. Design validation of an air cooled turbo generator by using fibre optic sensors in a shop test

    Science.gov (United States)

    Bosselmann, T.; Willsch, M.; Villnow, M.; Strack, S.; Chernogorski, V.; Weidner, J. R.; Roeding, R.; Schwanengel, U.; Trefflich, L.; Lindholm, S.; Abromitis, E.

    2012-06-01

    The increasing need of energy and the increasing share of renewables in electric power generation demands higher flexibility in the operation of conventional power plants. Turbo generators have to face higher stress during operation without consuming additional life time. For the first time in a shop test a new generator design was extensively evaluated by using about 250 fibre optic sensors - mostly new developed - to control temperature, strain, movement and vibration.

  2. Broadband optical parametric amplifier formed by two pairs of adjacent four-wave mixing sidebands in a tellurite microstructured optical fibre

    Science.gov (United States)

    Zhang, Lei; Tuan, Tong-Hoang; Kawamura, Harutaka; Nagasaka, Kenshiro; Suzuki, Takenobu; Ohishi, Yasutake

    2016-05-01

    A broadband fibre-optical parametric amplifier (FOPA) operating at a novel wavelength region that is far from the pump wavelength has been demonstrated by exploiting two pairs of adjacent four-wave mixing (FWM) sidebands generated simultaneously in a tellurite microstructured optical fibre (TMOF). Owing to the large nonlinearity of the TMOF and the high pump peak power provided by a picosecond laser, a maximal average gain of 65.1 dB has been obtained. When the FOPA is operated in a saturated state, a flat-gain amplification from 1424 nm to 1459 nm can be achieved. This broadband and high-gain FOPA operating at new wavelength regions far from the pump offers the prospect of all-optical signal processing.

  3. 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.

  4. 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.

  5. A fibre optic sensor for ambiguity measurement of apparent strain produced by electrical strain gauge-transient-heating-effect

    Energy Technology Data Exchange (ETDEWEB)

    El-Wakad, Mohamed-Tarek; Elsarnagawy, Tarek [King Saud Univ., Riyadh (Saudi Arabia)

    2010-07-01

    Strain gauges are useful sensors in many engineering and medical applications. When using one gauge for the measurement in quarter-bridge configurations, the electrical current flowing delivers power to the electrical strain gauge which causes a temperature rise (transient heat effect or THE), with a strain signal appearing as drift of the zero baseline. Fibre optic sensors on the other side are used to measure temperature as well as strain or force. The aim of this study is to evaluate the rise in temperature produced by the electrical strain gauge and to determine the equivalent apparent strain accordingly as a step towards using the reading to correct for the error due to the THE. The results of this study show that the optical fibre sensor is more sensitive compared to the semiconductor sensor used as a reference temperature sensor. The results also show the feasibility of determining the equivalent apparent strain values through reverse calculation of number of fringes resulting from the fibre optic sensor due to the temperature change. This was as an initial step to implement those values in the measuring electronic circuitry in order to eliminate the drift in the zero baselines. (orig.)

  6. From conventional sensors to fibre optic sensors for strain and force measurements in biomechanics applications: a review.

    Science.gov (United States)

    Roriz, Paulo; Carvalho, Lídia; Frazão, Orlando; Santos, José Luís; Simões, José António

    2014-04-11

    In vivo measurement, not only in animals but also in humans, is a demanding task and is the ultimate goal in experimental biomechanics. For that purpose, measurements in vivo must be performed, under physiological conditions, to obtain a database and contribute for the development of analytical models, used to describe human biomechanics. The knowledge and control of the mechanisms involved in biomechanics will allow the optimization of the performance in different topics like in clinical procedures and rehabilitation, medical devices and sports, among others. Strain gages were first applied to bone in a live animal in 40's and in 80's for the first time were applied fibre optic sensors to perform in vivo measurements of Achilles tendon forces in man. Fibre optic sensors proven to have advantages compare to conventional sensors and a great potential for biomechanical and biomedical applications. Compared to them, they are smaller, easier to implement, minimally invasive, with lower risk of infection, highly accurate, well correlated, inexpensive and multiplexable. The aim of this review article is to give an overview about the evolution of the experimental techniques applied in biomechanics, from conventional to fibre optic sensors. In the next sections the most relevant contributions of these sensors, for strain and force in biomechanical applications, will be presented. Emphasis was given to report of in vivo experiments and clinical applications.

  7. 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.

  8. The effect of humidity on annealing of polymer optical fibre bragg gratings

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Nielsen, Kristian; Bang, Ole

    2015-01-01

    The effect of humidity on annealing of PMMA based microstructured polymer optical fiber (mPOF) Bragg gratings is studied. Polymer optical fibers (POFs) are annealed in order to release stress formed during the fabrication process. Un-annealed fibers will have high hysteresis and low sensitivity...

  9. Chemometric tool for identification of iron-gall inks by use of visible-near infrared fibre optic reflection spectroscopy.

    Science.gov (United States)

    Gál, Lukáš; Čeppan, Michal; Reháková, Milena; Dvonka, Vladimír; Tarajčáková, Jarmila; Hanus, Jozef

    2013-11-01

    A method has been developed for identification of corrosive iron-gall inks in historical drawings and documents. The method is based on target-factor analysis of visible-near infrared fibre optic reflection spectra (VIS-NIR FORS). A set of reference spectra was obtained from model samples of laboratory-prepared inks covering a wide range of mixing ratios of basic ink components deposited on substrates and artificially aged. As criteria for correspondence of a studied spectrum with a reference spectrum, the apparent error in target (AET) and the empirical function SPOIL according to Malinowski were used. The capability of the proposed tool to distinguish corrosive iron-gall inks from bistre and sepia inks was evaluated by use of a set of control samples of bistre, sepia, and iron-gall inks. Examples are presented of analysis of historical drawings from the 15th and 16th centuries and written documents from the 19th century. The results of analysis based on the tool were confirmed by XRF analysis and colorimetric spot analysis.

  10. Chalcogenide Fibre Displacement Sensor

    Science.gov (United States)

    2001-06-01

    Fibre optic technology offers the possibility for developing of a variety of physical sensors for a wide range of physical parameters. The main...integrating sphere. The use of chalcogenide rather quartz fibre optic highly increases the Sensitivity of the sensor. Experimental set-up, transmission characteristics and technical parameters are presented.

  11. The crocidolite fibres interaction with human mesothelial cells as investigated by combining electron microscopy, atomic force and scanning near-field optical microscopy.

    Science.gov (United States)

    Andolfi, Laura; Trevisan, Elisa; Zweyer, Marina; Prato, Stefano; Troian, Barbara; Vita, Francesca; Borelli, Violetta; Soranzo, Maria Rosa; Melato, Mauro; Zabucchi, Giuliano

    2013-03-01

    In this study, we have performed a morphological analysis of crocidolite fibres interaction with mesothelial cells (MET5A) by combining conventional electron microscopy with atomic force (AFM) and scanning near-field optical microscopy (SNOM). After 6-h exposure at a crocidolite dose of 5 μg cm(-2), 90% of MET5A cells interact with fibres that under these conditions have a low cytotoxic effect. SEM images point out that fibres can be either engulfed by the cells that lose their typical morphology or they can accumulate over or partially inside the cells, which preserve their typical spread morphology. By using AFM we are able to directly visualize the entry-site of nanometric-sized fibres at the plasma membrane of the spread mesothelial cells. More importantly, the crocidolite fibres that are observed to penetrate the plasma membrane in SNOM topography can be simultaneously followed beneath the cell surface in the SNOM optical images. The analysis of SNOM data demonstrates the entrance of crocidolite fibres in proximity of nuclear compartment, as observed also in the TEM images. Our findings indicate that the combination of conventional electron microscopy with novel nanoscopic techniques can be considered a promising approach to achieve a comprehensive morphological description of the interaction between asbestos fibres and mesothelial cells that represents the early event in fibre pathogenesis.

  12. 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.

  13. Combining scanning haptic microscopy and fibre optic Raman spectroscopy for tissue characterization.

    Science.gov (United States)

    Candefjord, S; Murayama, Y; Nyberg, M; Hallberg, J; Ramser, K; Ljungberg, B; Bergh, A; Lindahl, O A

    2012-08-01

    The tactile resonance method (TRM) and Raman spectroscopy (RS) are promising for tissue characterization in vivo. Our goal is to combine these techniques into one instrument, to use TRM for swift scanning, and RS for increasing the diagnostic power. The aim of this study was to determine the classification accuracy, using support vector machines, for measurements on porcine tissue and also produce preliminary data on human prostate tissue. This was done by developing a new experimental set-up combining micro-scale TRM-scanning haptic microscopy (SHM)-for assessing stiffness on a micro-scale, with fibre optic RS measurements for assessing biochemical content. We compared the accuracy using SHM alone versus SHM combined with RS, for different degrees of tissue homogeneity. The cross-validation classification accuracy for healthy porcine tissue types using SHM alone was 65-81%, and when RS was added it increased to 81-87%. The accuracy for healthy and cancerous human tissue was 67-70% when only SHM was used, and increased to 72-77% for the combined measurements. This shows that the potential for swift and accurate classification of healthy and cancerous prostate tissue is high. This is promising for developing a tool for probing the surgical margins during prostate cancer surgery.

  14. 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...

  15. Biomimetic wet-stable fibres via wet spinning and diacid-based crosslinking of collagen triple helices

    CERN Document Server

    Arafat, M Tarik; Yin, Jie; Wood, David J; Russell, Stephen J

    2015-01-01

    One of the limitations of electrospun collagen as bone-like fibrous structure is the potential collagen triple helix denaturation in the fibre state and the corresponding inadequate wet stability even after crosslinking. Here, we have demonstrated the feasibility of accomplishing wet-stable fibres by wet spinning and diacid-based crosslinking of collagen triple helices, whereby fibre ability to act as bone-mimicking mineralisation system has also been explored. Circular dichroism (CD) demonstrated nearly complete triple helix retention in resulting wet-spun fibres, and the corresponding chemically crosslinked fibres successfully preserved their fibrous morphology following 1-week incubation in phosphate buffer solution (PBS). The presented novel diacid-based crosslinking route imparted superior tensile modulus and strength to the resulting fibres indicating that covalent functionalization of distant collagen molecules is unlikely to be accomplished by current state-of-the-art carbodiimide-based crosslinking. ...

  16. Strain and ground-motion monitoring at magmatic areas: ultra-long and ultra-dense networks using fibre optic sensing systems

    Science.gov (United States)

    Jousset, Philippe; Reinsch, Thomas; Henninges, Jan; Blanck, Hanna; Ryberg, Trond

    2016-04-01

    The fibre optic distributed acoustic sensing technology (DAS) is a "new" sensing system for exploring earth crustal elastic properties and monitoring both strain and seismic waves with unprecedented acquisition characteristics. The DAS technology principle lies in sending successive and coherent pulses of light in an optical fibre and measuring the back-scattered light issued from elastic scattering at random defaults within the fibre. The read-out unit includes an interferometer, which measures light interference patterns continuously. The changes are related to the distance between such defaults and therefore the strain within the fibre can be detected. Along an optical fibre, DAS can be used to acquire acoustic signals with a high spatial (every meter over kilometres) and high temporal resolution (thousand of Hz). Fibre optic technologies were, up to now, mainly applied in perimeter surveillance applications and pipeline monitoring and in boreholes. Previous experiments in boreholes have shown that the DAS technology is well suited for probing subsurface elastic properties, showing new ways for cheaper VSP investigations of the Earth crust. Here, we demonstrate that a cable deployed at ground surface can also help in exploring subsurface properties at crustal scale and monitor earthquake activity in a volcanic environment. Within the framework of the EC funded project IMAGE, we observed a >15 km-long fibre optic cable at the surface connected to a DAS read-out unit. Acoustic data was acquired continuously for 9 days. Hammer shots were performed along the surface cable in order to locate individual acoustic traces and calibrate the spatial distribution of the acoustic information. During the monitoring period both signals from on- and offshore explosive sources and natural seismic events could be recorded. We compare the fibre optic data to conventional seismic records from a dense seismic network deployed on Reykjanes. We show that we can probe and monitor earth

  17. Fibre-tree network for water-surface ranging using an optical time-domain reflectometry technique

    OpenAIRE

    Yoshiaki Yamabayashi; Tatsuya Yoshii; Masahiro Takanashi

    2014-01-01

    To monitor water level at long distance, a fibre-based time-domain reflectometry network is proposed. A collimator at each fibre end of a tree-type network retrieves 1.55 μm wavelength pulses that are reflected back from remote surfaces. Since this enables a power-supply-free sensor network with non-metal media, this system is expected to be less susceptible to lightning strikes and power cuts than conventional systems that use electrically powered sensors and metal cables. In the present Let...

  18. Reconfigurable high-speed optical fibre networks: Optical wavelength conversion and switching using VCSELs to eliminate channel collisions

    Science.gov (United States)

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

    2017-01-01

    We experimentally provide an alternative solution to channel collisions through up-wavelength conversion and switching by using vertical cavity surface-emitting lasers (VCSELs). This has been achieved by utilizing purely optical wavelength conversion on VCSELs at the low attenuation, 1550 nm transmission window. The corresponding transmission and bit error-rate (BER) performance evaluation is also presented. In this paper, two 1550 nm VCSELs with 50-150 GHz channel spacing are modulated with a 10 Gb/s NRZ PRBS 27-1 data and their interferences investigated. A channel interference penalty range of 0.15-1.63 dB is incurred for 150-50 GHz channel spacing without transmission. To avoid channel collisions and to minimize high interference penalties, the transmitting VCSEL with data is injected into the side-mode of a slave VCSEL to obtain a new up converted wavelength. A 16 dB extinction ratio of the incoming wavelength is achieved when a 15 dBm transmitting beam is injected into the side-mode of a -4.5 dBm slave VCSEL. At 8.5 Gb/s, a 1.1 dB conversion and a 0.5 dB transmission penalties are realized when the converted wavelength is transmitted over a 24.7 km G.655 fibre. This work offers a low-cost, effective wavelength conversion and channel switching to reduce channel collision probability by reconfiguring channels at the node of networks.

  19. A modified method for determining the focal ratio degradation and length properties of optical fibres in astronomy

    Science.gov (United States)

    Yan, Yunxiang; Wang, Gang; Sun, Weimin; Luo, A.-Li; Ma, Zhenyu; Li, Jian; Wang, Shuqing

    2017-04-01

    Focal ratio degradation (FRD) is a major contributor to throughput and light loss in a fibre spectroscopic telescope system. We combine the guided mode theory in geometric optics and a well-known model, the power distribution model (PDM), to predict and explain the FRD dependence properties. We present a robust method by modifying the energy distribution method with f-intercept to control the input condition. This method provides a way to determine the proper position of the fibre end on the focal plane to improve energy utilization and FRD performance, which lifts the relative throughput up to 95 per cent with variation of output focal ratio less than 2 per cent. This method can also help to optimize the arrangement of the position of focal-plane plate to enhance the coupling efficiency in a telescope. To investigate length properties, we modified the PDM by introducing a new parameter, the focal distance f, into the original model to make it available for a multiposition measurement system. The results show that the modified model is robust and feasible for measuring the key parameter d0 to simulate the transmission characteristics. The output focal ratio in the experiment does not follow the prediction trend but shows an interesting phenomenon: the output focal ratio increases first to the peak, then decreases and remains stable finally with increasing fibre length longer than 15 m. This provides a reference for choosing the appropriate length of fibre to improve the FRD performance for the design of the fibre system in a telescope.

  20. Analysis of intrinsic coupling loss in multi-step index optical fibres.

    Science.gov (United States)

    Aldabaldetreku, Gotzon; Durana, Gaizka; Zubia, Joseba; Arrue, Jon; Jiménez, Felipe; Mateo, Javier

    2005-05-02

    The main goal of the present paper is to provide a comprehensive analysis of the intrinsic coupling loss for multi-step index (MSI) fibres and compare it with those obtained for step- and graded-index fibres. We investigate the effects of tolerances to each waveguide parameter typical in standard manufacturing processes by carrying out several simulations using the ray-tracing method. The results obtained will serve us to identify the most critical waveguide variations to which fibre manufactures will have to pay closer attention to achieve lower coupling losses.