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  • 1.
    Alcusa-Saez, E. P.
    et al.
    University of Valencia, Spain.
    Diez, A.
    University of Valencia, Spain.
    Rivera-Perez, E.
    University of Valencia, Spain.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Norin, Lars
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Andres, M. V.
    University of Valencia, Spain.
    All-fiber acousto-optic tunable filter in polyimide coated optical fibers2017In: International Conference on Transparent Optical Networks, 2017Conference paper (Refereed)
    Abstract [en]

    We present the experimental demonstration of in-fiber acousto-optic coupling in a polyimide-coated optical fiber. Although the presence of the polyimide coating increases is significantly the attenuation of the acoustic wave, we show that acousto-optic interaction can still be produced with reasonable efficiency. The effect of the polyimide coating on the acousto-optic interaction process is analyzed in detailed. Theoretical and experimental results are in good agreement. To our knowledge, this is the first experimental demonstration of acousto-optic coupling in optical fibers with robust protective coating.

  • 2.
    Araujo, Leonardo F.
    et al.
    Pontifical Catholic University of Rio de Janeiro, Brazil.
    Etcheverry, Sebastián
    RISE, Swedish ICT, Acreo.
    da Costa, Greice Kelly Bezerra
    Federal Rural University of Rio de Janeiro, Brazil.
    Pereira, João M. B.
    Pontifical Catholic University of Rio de Janeiro, Brazil.
    Camara, Alexandre R.
    Rio de Janeiro State University, Brazil.
    de Matos, Christiano José Santiago
    Mackenzie Presbyterian University, Brazil.
    Margulis, Walter
    RISE, Swedish ICT, Acreo.
    Fontana, Jake
    United States Naval Research Laboratory, US.
    Carvalho, Isabel C. S.
    Pontifical Catholic University of Rio de Janeiro, Brazil.
    Photonics with special optical fibers and nanoparticles2016In: Optics InfoBase Conference Papers, 2016, article id LW3A.1Conference paper (Refereed)
    Abstract [en]

    Optical properties of nanorods in the presence of external electric field when confined to a special optical fiber was investigated, showing an increase of the longitudinal absorption peak in the presence of the field.

  • 3.
    Camara, Alexandre R.
    et al.
    Rio de Janeiro State University, Brazil; Pontifical Catholic University of Rio de Janeiro, Brazil.
    Pereira, Joao M. B.
    Pontifical Catholic University of Rio de Janeiro, Brazil.
    Tarasenko, Oleksandr
    RISE, Swedish ICT, Acreo, Fiber Optics.
    Margulis, Walter
    RISE, Swedish ICT, Acreo, Fiber Optics. KTH Royal Institute of Technology, Sweden.
    Carvalho, Isabel C. S.
    Pontifical Catholic University of Rio de Janeiro, Brazil.
    Optical creation and erasure of the linear electrooptical effect in silica fiber2015In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 23, no 14, p. 18060-18069Article in journal (Refereed)
    Abstract [en]

    We study the creation and erasure of the linear electrooptical effect in silicate fibers by optical poling. Carriers are released by exposure to green light and displaced with simultaneous application of an internal dc field. The second order nonlinear coefficient induced grows with poling bias. The field recorded (~108 V/m) is comparable to that obtained through classical thermal poling of fibers. In the regime studied here, the second-order nonlinearity induced (~0.06 pm/V) is limited by the field applied during poling (1.2 × 108 V/m). Optical erasure with high-power green light alone is very efficient. The dynamics of the writing and erasing process is discussed, and the two dimensional (2D) field distribution across the fiber is simulated.

  • 4.
    Carvalho, ICS
    et al.
    RISE, Swedish ICT, Acreo.
    Lesche, B
    RISE, Swedish ICT, Acreo.
    Margulis, Walter
    RISE, Swedish ICT, Acreo.
    Second order nonlinearities in optical fibers2002In: Polymer Optical Fibers / [ed] Nalwa, H., Los Angeles, CA, USA: American Scientific Publishers, 2002Chapter in book (Other academic)
  • 5.
    Carvalho, Isabel C. S.
    et al.
    Pontifical Catholic University of Rio de Janeiro, Brazil.
    Tarasenko, Oleksander
    RISE, Swedish ICT, Acreo.
    Camara, Alexandre R.
    Rio de Janeiro State University, Brazil.
    Pereira, Joäo M. B.
    Pontifical Catholic University of Rio de Janeiro, Brazil.
    Margulis, Walter
    RISE, Swedish ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Pockels fibers by optical poling2015In: Workshop on Specialty Optical Fibers and their Applications 2015, 2015, article id WT4A.22Conference paper (Refereed)
    Abstract [en]

    Silica fibers with internal electrodes biased with HV are poled when simultaneously excited by green light. The x(2) induced measured through the Pockels effect at 1.55 μm reaches ~0.11 pm/V. Poling and erasure are studied.

  • 6.
    Del Rosso, Tommaso
    et al.
    Pontifícia Universidade Católica do Rio de Janeiro, Brazil.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Fontana, Jake
    Naval Research Laboratory, US.
    Carvalho, Isabel C.S.
    Pontifícia Universidade Católica do Rio de Janeiro, Brazil.
    10 - Plasmonics for the Characterization of Metal Organic Films and Nanoparticles2019In: Metal Nanostructures for Photonics, Elsevier , 2019, p. 223-259Chapter in book (Other academic)
    Abstract [en]

    Here, we present an overview of the ellipsometric characterization of hybrid thin films and metal nanoparticles by surface plasmon resonance (SPR) spectroscopy, together with the dynamic control of the optical properties of the latter for applications in optoelectronic devices. A description of traditional techniques used for the determination of the thickness and refractive index of organic thin films deposited over the SPR planar sensing platforms is presented, with a discussion of the most recent applications in the ellipsometric characterization of thin film of metal nanoparticles and graphene layers. We conclude by describing recent results developing a dynamically tunable plasmonic pixel, where the electric-field-controlled alignment of gold nanorods in a colloidal suspension can enable optical switching at frequencies greater than megahertz.

  • 7.
    Estcheverry, Sebastián
    et al.
    RISE, Swedish ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Sudirman, Aziza
    Cobolt AB, Sweden.
    Laurell, Frederik
    KTH Royal Institute of Technology, Sweden.
    Margulis, Walter
    RISE, Swedish ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Playing cellular Golf in microstructured fibres2015In: Workshop on Specialty Optical Fibers and their Applications 2015, 2015, article id WF1A.1Conference paper (Refereed)
    Abstract [en]

    We illuminate particles in a solution using fibers with cladding holes. Particles sufficiently near the fiber tip and with the correct optical signature are collected into the holes with good specificity, mimicking cell-collection for diagnostics.

  • 8.
    Etcheverry, S.
    et al.
    KTH Royal Institute of Technology, Sweden.
    Faridi, A.
    KTH Royal Institute of Technology, Sweden.
    Ramachandraiah, H.
    KTH Royal Institute of Technology, Sweden.
    Margulis, Walter
    RISE, Swedish ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Laurell, F.
    KTH Royal Institute of Technology, Sweden.
    Russom, A.
    RISE, Swedish ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Optofludics in microstructured fibers combining particle elasto-inertial focusing and fluorescence2016In: 2016 Conference on Lasers and Electro-Optics (CLEO), 2016, article id 7789265Conference paper (Refereed)
    Abstract [en]

    Optofluidics is exploited in an all-fiber component to detect and identify through fluorescence particles flowing at high rate and inertially focused in a capillary. The system represents a first step towards an in-fiber flow cytometer.

  • 9.
    Etcheverry, Sebastian
    et al.
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Araujo, Leonardo F.
    PUC-RIO Pontifícia Universidade Católica do Rio de Janeiro, Brazil.
    Carvalho, Isabel C. S.
    PUC-RIO Pontifícia Universidade Católica do Rio de Janeiro, Brazil.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Fontana, Jake
    Naval Research Laboratory, USA.
    Digital electric field induced switching of plasmonic nanorods using an electro-optic fluid fiber2017In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 111, no 22, article id 221108Article in journal (Refereed)
    Abstract [en]

    We demonstrate the digital electric field induced switching of plasmonic nanorods between "1" and "0" orthogonal aligned states using an electro-optic fluid fiber component. We show by digitally switching the nanorods that thermal rotational diffusion of the nanorods can be circumvented, demonstrating an approach to achieve submicrosecond switching times. We also show, from an initial unaligned state, that the nanorods can be aligned into the applied electric field direction in 110 ns. The high-speed digital switching of plasmonic nanorods integrated into an all-fiber optical component may provide opportunities for remote sensing and signaling applications. © 2017 Author(s).

  • 10.
    Etcheverry, Sebastian
    et al.
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Araujo, Leonardo F.
    Pontifical Catholic University of Rio de Janeiro, Brazil.
    da Costa, Greice K. B.
    Rural Federal University of Rio de Janeiro, Brazil.
    Pereira, Joao M. B.
    Pontifical Catholic University of Rio de Janeiro, Brazil.
    Camara, Alexandre R.
    Rio de Janeiro State University, Brazil.
    Naciri, Jawad
    Naval Research Laboratory, USA.
    Ratna, Banahalli R.
    Naval Research Laboratory, USA.
    Hernández-Romano, Ivan
    University of Guanajuato, Mexico; Mackenzie Presbyterian University, Brazil.
    de Matos, Cristiano J. S.
    Mackenzie Presbyterian University, Brazil.
    Carvalho, Isabel C. S.
    Pontifical Catholic University of Rio de Janeiro, Brazil.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Fontana, Jake
    Naval Research Laboratory, USA.
    Microsecond switching of plasmonic nanorods in an all-fiber optofluidic component2017In: Operator Theory: Advances and Applications, ISSN 1004-4469, E-ISSN 2334-2536, Vol. 4, no 8, p. 864-870Article in journal (Refereed)
    Abstract [en]

    As information technologies move from electron- to photon-based systems, the need to rapidly modulate light is of paramount importance. Here, we study the evolution of the electric-field-induced alignment of gold nanorods suspended in organic solvents. The experiments were performed using an all-fiber optofluidic device, which enables convenient interaction of light, electric fields, and the nanorod suspension. We demonstrate microsecond nanorod switching times, three orders of magnitude faster than a traditional Freederickcz-based liquid crystal alignment mechanism. We find that the dynamics of the alignment agrees well with the Einstein–Smoluchowski relationship, allowing for the determination of the rotational diffusion coefficient and polarizability anisotropy of the nanorods as well as the effective length of the ligands capping the nanorods. The ability to dynamically control the optical properties of these plasmonic suspensions coupled with the point-to-point delivery of light from the fiber component, as demonstrated in this work, may enable novel ultrafast optical switches, filters, displays, and spatial light modulators.

  • 11.
    Etcheverry, Sebastian
    et al.
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Russom, A.
    KTH Royal Institute of Technology, Sweden.
    Laurell, F.
    KTH Royal Institute of Technology, Sweden.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Trapping and optical identification of microparticles in a liquid with a functional optical fiber probe2018In: Conference on Lasers and Electro-Optics OSA Technical Digest (online) (Optical Society of America, 2018), paper AM4P.6, 2018Conference paper (Refereed)
    Abstract [en]

    A fiber probe traps single micrometer-particles by fluid suction into a hollow microstructure and enables optical identification by the fluorescence light collected in a fiber core. The probe finds applications in life-science and environmental monitoring.

  • 12.
    Etcheverry, Sebastián
    et al.
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Araujo, Leonardo
    Universidade Federal de Pernambuco, Brazil.
    Carvalho, Isabel
    Universidade Federal de Pernambuco, Brazil.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Fontana, Jake
    Naval Research Laboratory, USA.
    Sub-microsecond switching times using dynamically tunable plasmonic pixels2018Conference paper (Refereed)
    Abstract [en]

    Liquid crystal based devices can arbitrarily control the amplitude, phase and polarization of light, enabling disruptive technologies such as flat screen televisions and smart phones. Yet, the Achilles heel of these devices are their slow, millisecond switching speeds, constraining potential applications. Here we develop the concept of a dynamic plasmonic pixel as a novel paradigm for liquid crystal devices using the electric field controlled alignment of gold nanorods. Experiments were performed using an electro-optic fluid fiber device, which enabled convenient interaction of light, electric fields and the nanorod suspension. We studied the evolution of the electric-field induced alignment of gold nanorods and demonstrate microsecond switching times, 3 orders of magnitude faster than a traditional Freederickcz-based liquid crystal alignment mechanism. We find that the dynamics of the alignment agrees well with the Einstein-Smoluchowski relationship. Furthermore, by digitally switching the nanorods between orthogonally aligned states, we show switching frequencies greater than MHz can be achieved. The development of these dynamically tunable plasmonic pixels may lead to ultrafast optical switches, filters, displays and spatial light modulators.

  • 13.
    Etcheverry, Sebastián
    et al.
    RISE, Swedish ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Faridi, Muhammad Asim
    KTH Royal Institute of Technology, Sweden.
    Ramachandraiah, Harisha
    KTH Royal Institute of Technology, Sweden.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Laurell, Fredrik
    KTH Royal Institute of Technology, Sweden.
    Russom, Aman
    KTH Royal Institute of Technology, Sweden.
    All fiber based micro-flow cytometer by combining optical fiber with inertial focusing2016In: 20th International Conference on Miniaturized Systems for Chemistry and Life Sciences (MicroTAS 2016), 2016, Vol. 3, p. 1655-1656Conference paper (Refereed)
    Abstract [en]

    Towards a portable point of care flow cytometry platform, we present here an integrated all optical fiber-based optofluidic system capable of counting and discriminating fluorescent particles and cells. The robust and compact device incorporates optical fibers and circular capillaries to build an all-fiber optofluidic device to enable counting particles based on their fluorescent and back-scatter light emission. Here, we combine this with inertial- and elasto-inertial microfluidics for sheathless particle and cell focusing for integrated detection with scattering and fluorescence detections - all necessary components of standard cytometers. We validated the system for cell counting based on scattering and fluorescence.

  • 14.
    Etcheverry, Sebastián
    et al.
    RISE, Swedish ICT, Acreo, Fiber Optics. KTH Royal Institute of Technology, Sweden.
    Sudirman, Aziza
    RISE, Swedish ICT, Acreo, Fiber Optics. KTH Royal Institute of Technology, Sweden.
    Margulis, Walter
    RISE, Swedish ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Laurell, Fredrik
    KTH Royal Institute of Technology, Sweden.
    Identification and collection of particles with optical fibers2015In: Novel Biophotonics Techniques and Applications III / [ed] Arjen Amelink, I. Alex Vitkin, 2015, Vol. 9540, article id 95400NConference paper (Refereed)
    Abstract [en]

    A micro-structured fiber-based system for identification and collection of fluorescent particles is demonstrated. An optical fiber probe with longitudinal holes in the cladding is used to retrieve fluorescent particles by exerting microfluidics forces. Laser induced fluorescent (LIF) is carried out by the fiber probe and an optical setup. When a particle with a previously chosen fluorescence wavelength is identified, a vacuum pump is activated collecting the particle into a hole. Green and red fluorescent polystyrene particles were detected and selectively retrieved.

  • 15.
    Fanjoux, G.
    et al.
    FEMTO-ST institute, France.
    Sudirman, Aziza
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Beugnot, J. -C
    FEMTO-ST institute, France.
    Furfaro, L.
    FEMTO-ST institute, France.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Sylvestre, T.
    FEMTO-ST institute, France.
    Towards supercontinuum generation by stimulated Raman-Kerr scattering in an integrated nonlinear liquid core fiber2015In: Proceedings 2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference, CLEO/Europe-EQEC 2015, Optical Society of America (OSA) , 2015Conference paper (Refereed)
  • 16.
    Fanjoux, Gil
    et al.
    FEMTO-ST Institute, France.
    Sudirman, Aziza
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Beugnot, Jean-Charles
    FEMTO-ST Institute, France.
    Furfaro, Luca
    FEMTO-ST Institute, France.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Sylvestre, Thibaut
    FEMTO-ST Institute, France.
    Towards supercontinuum generation by stimulated Raman-Kerr scattering in an integrated nonlinear liquid core fiber2015In: The European Conference on Lasers and Electro-Optics 2015, Optical Society of America (OSA) , 2015, article id CD_6_3Conference paper (Refereed)
    Abstract [en]

    Integrated liquid-core optical fibers (LCOF) have recently emerged as new photonic platforms for their wide range of potential applications in nonlinear photonics [1,2]. Their advantages over solid-core glass fibers include broad transparency from the UV to the mid-IR and enhanced nonlinear optical effects. For instance, enhanced stimulated Raman scattering (SRS) has recently been demonstrated using carbon disulfide, Toluene or ethanol nonlinear liquids in integrated all-fiber systems compatible with standard single-mode fibers (SMFs) [1,2].

  • 17.
    Franciscangelis, C.
    et al.
    State University of Campinas, Brazil.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Floridia, C.
    CPqD, Brazil.
    Rosolem, J. B.
    CPqD, Brazil.
    Salgado, F. C.
    CPqD, Brazil.
    Nyman, T.
    Saab AB, Sweden.
    Petersson, M.
    Saab AB, Sweden.
    Hallander, P.
    Saab AB, Sweden.
    Hällstrom, S.
    KTH Royal Institute of Technology, Sweden.
    Söderquist, I.
    Saab AB, Sweden.
    Fruett, F.
    State University of Campinas, Brazil.
    Vibration measurement on composite material with embedded optical fiber based on phase-OTDR2017In: Proceedings of SPIE - The International Society for Optical Engineering Volume 10168, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2017; 101683Q (2017), 2017, article id 101683QConference paper (Refereed)
    Abstract [en]

    Distributed sensors based on phase-optical time-domain reflectometry (phase-OTDR) are suitable for aircraft health monitoring due to electromagnetic interference immunity, small dimensions, low weight and flexibility. These features allow the fiber embedment into aircraft structures in a nearly non-intrusive way to measure vibrations along its length. The capability of measuring vibrations on avionics structures is of interest for what concerns the study of material fatigue or the occurrence of undesirable phenomena like flutter. In this work, we employed the phase-OTDR technique to measure vibrations ranging from some dozens of Hz to kHz in two layers of composite material board with embedded polyimide coating 0.24 numerical aperture single-mode optical fiber. © 2017 SPIE.

  • 18.
    Franciscangelis, Carolina
    et al.
    University of Campinas, Brazil.
    Fruett, Fabiano
    University of Campinas, Brazil.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Kjellberg, Leif
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Floridia, Claudio
    CPqD, Brazil.
    Real-time multiple machines sound listening using a phase-OTDR based distributed microphone2017In: SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference, IMOC 2017, 2017Conference paper (Refereed)
    Abstract [en]

    We propose and experimentally demonstrate a spatially tunable phase-OTDR based distributed microphone for listening to the sound of multiple machines. The distributed acoustic sensing capability, allied with the real-time spatial tuning, enables listening to a drill and to a cooling water system pump placed in two different sections along a single optical fiber, one at a time. The recorded acoustic waveform profile of both machines agreed with their operating cycles. Moreover, the sounds generated by both engines are successfully distinguished with the proposed method even when both machines are operating simultaneously..

  • 19.
    Franciscangelis, Carolina
    et al.
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Lindblom, Magnus
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Tow, Kenny
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Sjölander, Ola
    KTH Royal Institute of Technology, Sweden.
    Kahlman, Lars
    SKF AB, Sweden.
    Bankeström, Olle
    SKF AB, Sweden.
    On-field validation of real-Time phase-OTDR for roller bearing monitoring2019In: Proceedings of SPIE - The International Society for Optical Engineering, SPIE , 2019Conference paper (Refereed)
    Abstract [en]

    This work presents an on-field validation of an in-house built real-Time phase-OTDR for monitoring the status of roller bearings. The acoustic sensor prototype was designed and assembled at RISE and evaluated on a 1 m diameter bearing at SKF AB facilities in Göteborg, Sweden. A 0.24 numerical aperture single-mode optical fiber was installed in the bearing lubrication groove, which is 50 mm large and 5 mm deep. Tests were performed to verify the response of the phaseOTDR to acoustic emissions in the bearing such as hammer hits and running the rollers at different loads. The fiber optic sensor results agree with the measurements performed by a standard industrial high sensitivity electronic accelerometer used for comparison. Moreover, as opposed to the reference electronic sensor, the phase-OTDR proved to be insensitive to electrical disturbances present on the environment.

  • 20.
    Garcia-Ruiz, Andres
    et al.
    University of Alcalá, Spain.
    Martins, Hugo
    University of Alcalá, Spain.
    Magalhães, Regina
    University of Alcalá, Spain.
    Pereira, Joao
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Tarasenko, Oleksandr
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Norin, Lars
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Martin-Lopez, Sonia
    University of Alcalá, Spain.
    Gonzalez-Herraez, Miguel
    University of Alcalá, Spain.
    Hermetic all-fiber phase modulators using Joule heating in carbon-coated fibers2018In: Optics InfoBase Conference Papers, 2018Conference paper (Refereed)
    Abstract [en]

    Certain applications of fiber sensors (e.g. avionics, oil industry) imply extreme operating conditions spurring the development of hermetic all-fiber devices. We present a hermetic all-fiber phase modulator based on Joule heating in a carbon-coated fiber. 

  • 21.
    Garcia-Ruiz, Andres
    et al.
    University of Alcala, Spain.
    Martins, Hugo
    University of Alcala, Spain.
    Magalhães, Regina
    University of Alcala, Spain.
    Pereira, Joao
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Tarasenko, Oleksandr
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Norin, Lars
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Martin-Lopez, Sonia
    University of Alcala, Spain.
    Gonzalez-Herraez, Miguel
    University of Alcala, Spain.
    Hermetic carbon coatings for electro-thermal all-fiber phase modulators2019In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213Article in journal (Refereed)
    Abstract [en]

    Joule effect and thermal response of several carbon coated fibers are modelled and analysed. An electro thermally driven all-fiber phase modulator based on these principles is proposed and a proof of concept of it is characterized. This kind of fibers could be the basis for developing all fiber components aimed to operate in environments where the strength increase and impermeability to hydrogen diffusion guaranteed by the carbon coating is crucial.

  • 22.
    Gerosa, Rodrigo M.
    et al.
    Mackenzie Presbyterian University, Brazil.
    Sudirman, Aziza
    RISE, Swedish ICT, Acreo, Fiber Optics. KTH Royal Institute of Technology, Sweden.
    Menezes, Leonardo de S.
    Federal University of Pernambuco, Brazil.
    Margulis, Walter
    RISE, Swedish ICT, Acreo, Fiber Optics. KTH Royal Institute of Technology, Sweden.
    de Matos, Christiano J. S.
    Mackenzie Presbyterian University, Brazil.
    All-fiber high repetition rate dye laser2015In: Optical Society of America. Journal A: Optics, Image Science, and Vision, ISSN 1084-7529, E-ISSN 1520-8532, Vol. 2, no 2, p. 186-193Article in journal (Refereed)
    Abstract [en]

    Optofluidic dye lasers may play a significant role in future laser applications in numerous areas, combining wavelength flexibility with integration and ease of operation. Nevertheless, no all-fiber integrated dye lasers have been demonstrated so far. In this paper, we report on a series of optofluidic all-fiber Rhodamine optical sources operating at a repetition rate as high as 1 kHz. Dye bleaching is avoided by circulating the Rhodamine dye during optical excitation. The laser radiation is extracted via conventional fibers that are spliced to the dye-filled capillary active medium. A tuneable amplified spontaneous emission source, a multimode laser, and a few transverse-mode laser are demonstrated by adjusting the setup. Threshold pump energies as low as similar to 1 mu J and slope efficiencies of up to mu 9% were obtained, indicating the potential for realworld applications in areas such as spectroscopy and biomedicine.

  • 23.
    Gladyshev, Alexey V.
    et al.
    Russian Academy of Sciences, Russia.
    Corbari, Costantino
    University of Southampton, UK.
    Tarasenko, Oleksander
    RISE, Swedish ICT, Acreo.
    Yatsenko, Yu P.
    Russian Academy of Sciences, Russia.
    Semjonov, Sexrgei L.
    Russian Academy of Sciences, Russia.
    Margulis, Walter
    RISE, Swedish ICT, Acreo.
    Kazansky, Peter G.
    University of Southampton, UK.
    Hernandez, Yves
    Multitel, Belgium.
    Second-order nonlinearity in optical fibers: Achievements and perspectives2016In: Optics InfoBase Conference Papers: Bragg Gratings, Photosensitivity and Poling in Glass Waveguides and Materials, 2016Conference paper (Refereed)
    Abstract [en]

    Recent progress in thermal poling of silica fibers is reviewed. It is demonstrated that state-of-the-art poled fibers can be used in a number of practical applications. Challenges for further development of poled fiber devices are discussed and possible solutions proposed.

  • 24.
    Gouvêa, Paula M. P.
    et al.
    Pontifical Catholic University of Rio de Janeiro, Brazil.
    Rugeland, Patrik
    RISE, Swedish ICT, Acreo.
    Gomes, Marcos S. P.
    Pontifical Catholic University of Rio de Janeiro, Brazil.
    Margulis, Walter
    RISE, Swedish ICT, Acreo.
    Component and setup for insertion of gases in a hollow-core optical fiber sensor2015In: 24th International Conference on Optical Fibre Sensors / [ed] Hypolito José Kalinowski, José Luís Fabris, Wojtek J. Bock, 2015, Vol. 9634, article id 96343DConference paper (Refereed)
    Abstract [en]

    An optical fiber component and setup were developed to insert and remove gases from hollow-core optical fibers, allowing gas/light mixing over the length of the fiber for gas sensing applications. Transmitted signals acquired at the output of the fiber contain information regarding absorption occurring inside the fiber, providing a spectroscopic signature of the gas or gases in the fiber. Spectra for 1 atm of acetylene (C2H2) around 1525 nm and 1 atm of carbon dioxide (CO2) around 1432 nm were obtained and compared to HITRAN data, showing good agreement. The setup can also be used to prepare gas cells.

  • 25. Jason, Johan
    et al.
    Rugeland, Patrik
    RISE, Swedish ICT, Acreo.
    Tarasenko, Oleksandr
    RISE, Swedish ICT, Acreo.
    Margulis, Walter
    RISE, Swedish ICT, Acreo.
    Nilsson, Hans-Erik
    Temperature characteristics of the birefringence properties of filled side-hole fibers.2013In: Applied Optics, ISSN 0003-6935, E-ISSN 1539-4522, Vol. 52, no 21, p. 5208-5215Article in journal (Refereed)
    Abstract [en]

    The temperature characteristics of the birefringence of side-hole fibers filled with liquids or metal are investigated, aiming at providing a basis for on/off temperature sensing. Short pieces of fiber are filled and the change in birefringence is registered using measurements in reflective mode of the transmitted power through a linear polarizer at 1550 nm. The rapid change in the birefringence behavior of the fiber at the temperature of the phase transition of the filler substance is shown, and from the measurement data the phase transition temperatures can be determined as well as an estimation of the birefringence change with temperature. The experimental results are supported by numerical simulations.

  • 26.
    Konstantinou, Maria G.
    et al.
    Foundation for Research and Technology-Hellas, Greece.
    Kosma, Kyriaki
    Foundation for Research and Technology-Hellas, Greece.
    Margulis, Walter
    RISE, Swedish ICT, Acreo.
    Pissadakis, Stavros
    Foundation for Research and Technology-Hellas, Greece.
    A microspherical resonator embedded inside a microstructured optical fiber taper2015In: Workshop on Specialty Optical Fibers and their Applications (WSOF 2015), 2015, article id WT4A.23Conference paper (Refereed)
    Abstract [en]

    The integration of a microspherical whispering gallery mode (WGM) resonator inside a microstructured optical fiber taper is demonstrated. Preliminary WGM spectra of this in-fiber resonator in transmission mode are presented and discussed.

  • 27.
    Konstantinou, Maria Georgia
    et al.
    Foundation for Research and Technology – Hellas, Greece; National Technical University of Athens, Greece.
    Milenko, Karolina
    Foundation for Research and Technology – Hellas, Greece.
    Kosma, Kyriaki
    Foundation for Research and Technology – Hellas, Greece.
    Margulis, Walter
    RISE, Swedish ICT, Acreo.
    Pissadakis, Stavros
    Foundation for Research and Technology – Hellas, Greece.
    Light coupling and routing using a microsphere attached on the endface of a microstructured optical fiber2016In: Proceedings of SPIE: Micro-Structured and Specialty Optical Fibres IV, 2016, Vol. 9886, article id 98860IConference paper (Refereed)
    Abstract [en]

    Herein, we demonstrated a T-shaped whispering gallery modes (WGMs) excitation system including a tapered single mode fiber (SMF), a tapered microstructured optical fiber (MOF) and a BaTiO3 microsphere for efficient light coupling and routing between the two fibers. The BaTiO3 microsphere is semi-immersed into the capillary of a tapered MOF, while the tapered SMF is placed perpendicularly to MOF in a contact with equatorial region of the microsphere. Based on that, three channels joined by the microsphere are formed, and excitation and measurement of WGMs is possible either using the SMF or the MOF taper. The measured WGMs spectra reveal light routing along Q-factors between 4500 and 6100, along with scattering signal with all three fiber ports and parities.

  • 28.
    Lago, L.
    et al.
    Multitel ASBL, Belgium.
    Corbari, C.
    University of Southampton, UK.
    Gladyshev, A. V.
    Fibre Optics Research Center, Russia.
    Kazansky, P. G.
    University of Southampton, UK.
    Tarasenko, O.
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Margulis, Walter
    RISE, Swedish ICT, Acreo.
    Hernandez, Y.
    Multitel ASBL, Belgium.
    Specialty fibres and components for advanced microscopy2014In: Specialty Optical Fibers, SOF 2014, 2014Conference paper (Refereed)
    Abstract [en]

    We investigate fibre basic functions like SHG and pulse gating. We achieved 5.2% conversion efficiency into green light with 50 W peak pump power and demonstrated in-fibre pulse gating at 1 MHz repetition rate. © 2014 OSA.

  • 29.
    Magalhaes, Regina
    et al.
    University of Alcala, Spain.
    Garcia-Ruiz, Andres
    University of Alcala, Spain.
    Martins, Hugo
    University of Alcala, Spain.
    Pereira, Joao
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Martin-Lopez, Sonia
    University of Alcala, Spain.
    Gonzalez-Herraez, Miguel
    University of Alcala, Spain.
    Fiber-based distributed bolometry2019In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 27, no 4, p. 4317-4328Article in journal (Refereed)
    Abstract [en]

    Optical fibers are inherently designed to allow no interaction between the guided light and the surrounding optical radiation. Thus, very few optical fiber-based technologies exist in the field of optical radiation sensing. Accomplishing fully-distributed optical radiation sensing appears then as even more challenging since, on top of the lack of sensitivity explained above, we should add the need of addressing thousands of measurement points in a single, continuous optical cable. Nevertheless, it is clear that there exist a number of applications which could benefit from such a distributed sensing scheme, particularly if the sensitivity was sufficiently high to be able to measure correctly variations in optical radiation levels compatible with the earth surface. Distributed optical radiation sensing over large distances could be employed in applications such as Dynamic Line Rating (DLR), where it is known that solar radiation can be an important limiting factor in energy transmission through overhead power cables, and also in other applications such as thermo-solar energy. In this work, we present the proof-of-concept of the first distributed bolometer based on optical fiber technology and capable of detecting absolute changes of irradiance. The core idea of the system is the use of a special fiber coating with high emissivity (e.g., carbon coating or black paint). The high absorption of these coatings translates into a temperature change that can be read with sufficiently high sensitivity using phase-sensitive reflectometry. To demonstrate the concept, we interrogate distinct black-coated optical fibers using a chirped-pulse ÖOTDR, and we readily demonstrate the detection of light with resolutions in the order of 1% of the reference solar irradiance, offering a high-potential technology for integration in the aforementioned applications.

  • 30.
    Magalhães, Regina
    et al.
    University of Alcalá, Spain.
    Garcia-Ruiz, Andres
    University of Alcalá, Spain.
    Martins, Hugo
    University of Alcalá, Spain.
    Pereira, Joao
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Martin-Lopez, Sonia
    University of Alcalá, Spain.
    González-Herráez, Miguel
    University of Alcalá, Spain.
    Distributed detection of optical radiation using chirped-pulse phase-sensitive optical time domain reflectometry2018In: Optics InfoBase Conference Papers, 2018Conference paper (Refereed)
    Abstract [en]

    A distributed bolometer operating over transparent-coated and carbon-coated optical fibers is proposed. The detection of light with irradiance sensitivities of in the order of 1% of the reference solar irradiance is readily demonstrated. 

  • 31.
    Magalhães, Regina
    et al.
    University of Porto, Portugal.
    Pereira, Joao
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Garcia-Ruiz, Andres
    University of Alcalá, Spain.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Martin-Lopez, Sonia
    University of Alcalá, Spain.
    Gonzalez-Herraez, Miguel
    University of Alcalá, Spain.
    Martins, Hugo
    Institute of Optics, Spain.
    Distributed detection of quadratic Kerr effect in silica fibers using chirped-pulse φoTDR2019In: Proceedings of SPIE - The International Society for Optical Engineering, SPIE , 2019Conference paper (Refereed)
    Abstract [en]

    Monitoring the presence of external electric fields over large distances and detecting losses along power transmission networks, is of extreme importance nowadays due to concerns with environment, efficiency, cost and safety. In this work, we evaluate a method to achieve distributed measurements of the quadratic electro-optic Kerr effect in silica fibers in a distributed way. For this purpose, we integrate a twin-hole fiber filled with BiSn alloy electrodes and monitor its electric-field induced refractive index (RI) change Δn by using a chirped-pulse phase-sensitive OTDR (CP-ΦOTDR). By exploiting its high sensitivity (RI changes of the order of 10-9), we demonstrate that the proposed system is able to detect the intrinsic quadratic electrooptic nonlinearity (the electric Kerr effect) in the fiber, an effect that is usually considered to be too weak to be exploited for practical applications. Additionally, we show that the CP-ΦOTDR is sufficiently sensitive to measure the electric Kerr effect with untreated standard telecommunication fibers under realistic fields.

  • 32.
    Malmström, Mikael
    et al.
    KTH Royal Institute of Technology, Sweden; Uppsala University, Sweden.
    Tarasenko, Oleksander
    RISE, Swedish ICT, Acreo.
    Margulis, Walter
    RISE, Swedish ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Laurell, Fredrik
    KTH Royal Institute of Technology, Sweden.
    All-Fiber Nanosecond Gating for Time-Resolved Spectral Analysis2016In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 28, no 8, p. 829-832, article id 7381625Article in journal (Refereed)
    Abstract [en]

    We demonstrate the addition of time gating to a standard optical spectrum analyzer (OSA) operating in the spectral region ∼ 1.06 μm. This is accomplished by opening for 7 ns the optical input to the OSA with an electrically driven poled fiber in a Sagnac loop. The sequential interrogation with nanosecond resolution of the reflection from three fiber Bragg gratings along a piece of fiber allows distinguishing the spectral peaks created with a minimum separation of 85 cm. The passive extinction ratio of this device is >40 dB and returns to >40 dB from >23 dB on a 35-ns time scale directly after time gating.

  • 33.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Integration of optoelectronics into fibres enhances textiles2018In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 560, no 7717, p. 170-171Article in journal (Other academic)
  • 34.
    Munoz, Daniel M.
    et al.
    University of Brasilia, Brazil.
    Franciscangelis, Carolina
    University of Campinas, Brazil.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Fruett, Fabiano
    University of Campinas, Brazil.
    Soderquist, Ingemar
    Saab AB, Sweden.
    Low latency disturbance detection using distributed optical fiber sensors2017In: Proceedings of the 2017 IEEE 14th International Conference on Networking, Sensing and Control, ICNSC 2017, 2017, p. 372-377Conference paper (Refereed)
    Abstract [en]

    Distributed optical fiber sensors based on phase-sensitive optical time domain reflectometry (Φ-OTDR) are feasible options to detect perturbations in kilometric security perimeters or mechanical structures. This technique takes advantage of electromagnetic interference immunity, small dimensions, lightweight, flexibility, and capability. Moreover, this technique can be combined with dedicated hardware architectures, in order to improve its performance and reliability. This work proposes the use of parallel hardware architectures to implement real-time detecting and locating perturbations in a Φ-OTDR distributed optical fiber vibration sensor. Hardware architectures of the iterative moving average filter and the Sobel filter were mapped on field programmable gate arrays, exploring the intrinsic parallelism in order to achieve real-time requirements. A performance comparison between the proposed solutions was addressed in terms of hardware cost, latency and power consumption.

  • 35.
    Pereira, J. M. B.
    et al.
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Camara, A. R.
    Universidade Do Estado Do Rio de Janeiro, Brazil.
    Laurell, F.
    KTH Royal Institute of Technology, Sweden.
    Tarasenko, Oleksander
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Poling Optical Fibers with UV Lamp2019In: 2019 Conference on Lasers and Electro-Optics, CLEO 2019 - Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2019Conference paper (Refereed)
    Abstract [en]

    Silicate fibers with internal electrodes are optically poled without a laser by side-exposure to radiation from a UV tubular lamp. Electrooptic coefficients κ(2)∼ 0.04 pm/V and Vπ = 810 V are obtained

  • 36.
    Pereira, Joao
    et al.
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Camara, Alexandre
    Universidade do Estado do Rio de Janeiro, Brazil.
    Laurell, Fredrik
    KTH Royal Institute of Technology, Sweden.
    Tarasenko, Oleksander
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Linear electro-optical effect in silica fibers poled with ultraviolet lamp2019In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 27, no 10, p. 14893-14902Article in journal (Refereed)
    Abstract [en]

    A second-order nonlinearity was induced in silica fibers poled by exposure to ultraviolet (UV) radiation and simultaneous high voltage applied to internal electrodes. The UV light source was a tubular lamp with spectral peak at 254 nm. The highest second-order nonlinear coefficient measured through the linear electro-optic effect was 0.062 pm/V. The erasure of the recorded voltage with UV excitation was studied, and the stability of the poled fiber at a temperature exceeding ~400 K was investigated. By eliminating the use of a focused laser beam as excitation source, the technique enables poling many pieces of fiber in parallel.

  • 37.
    Pereira, Joao
    et al.
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Camara, Alexandre
    Universidade do Estado do Rio de Janeiro, Brazil; .
    Laurell, Fredrik
    KTH Royal Institute of Technology, Sweden.
    Tarasenko, Oleksandr
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Poling optical fibers with UV lamp2019In: Conference on Lasers and Electro-Optics OSA Technical Digest (Optical Society of America, 2019), paper SM2L.5, OSA - The Optical Society , 2019, article id SM2L.5Conference paper (Refereed)
    Abstract [en]

    Silicate fibers with internal electrodes are optically poled without a laser by side-exposure to radiation from a UV tubular lamp. Electrooptic coefficients χ(2) ~ 0.04 pm/V and Vπ = 810 V are obtained.

  • 38.
    Pereira, Joao
    et al.
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Hervás, J.
    Universitat Politècnica de València, Spain.
    Barrera, D.
    Universitat Politècnica de València, Spain.
    Madrigal, J.
    Universitat Politècnica de València, Spain.
    Sales, S.
    Universitat Politècnica de València, Spain.
    Laurell, F.
    University of Alcalá, Spain.
    Tarasenko, Oleksander
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    High-voltage fiber sensor based on fiber Bragg grating in poled fiber2019In: Proceedings of SPIE - The International Society for Optical Engineering, SPIE , 2019Conference paper (Refereed)
    Abstract [en]

    Fiber Bragg gratings (FBGs) in a poled silicate fiber are used to detect external voltage applied to the fiber's internal electrodes. This work shows a basic proof-of-concept of a single-ended, fiber-based voltage sensor that can be used to measure periodic high-voltage signals. The setup can be extended to a multiplexed e-field interrogation system and used in the electric power industry for remote sensing of transmission lines and power plants..

  • 39.
    Romagnoli, Priscila
    et al.
    Mackenzie Presbyterian University, Brazil.
    Rosa, Henrique G.
    Mackenzie Presbyterian University, Brazil.
    Lopez-Cortes, Daniel
    Mackenzie Presbyterian University, Brazil.
    Souza, Eunézio A. T.
    Mackenzie Presbyterian University, Brazil.
    Viana-Gomes, José C.
    National University of Singapore, Singapore.
    Margulis, Walter
    RISE, Swedish ICT, Acreo, Fiber Optics.
    de Matos, Christiano J. S.
    Mackenzie Presbyterian University, Brazil.
    Making Graphene Visible on Transparent Dielectric Substrates: Brewster Angle Imaging2015In: 2D Materials, ISSN 2053-1583, Vol. 2, no 3, article id 035017Article in journal (Refereed)
    Abstract [en]

    The visibility of graphene is greatly increased by illuminating samples deposited on transparent dielectrics at the substrates' Brewster angle. Using a commercial ellipsometer, the reflectivity of monolayers of chemical vapour deposition (CVD) graphene is found to be up to 33 times higher than that of the substrate, i.e., an optical contrast as high as 3200% is obtained, more than 380 times higher than with standard optical microscopy.

    Also, with a simpler, homemade, experimental setup, a 1400% optical contrast was measured for a monolayer of CVD graphene and linear features as small as ~20 μm were visible in a monolayer, while ~6 × 17 μm2trilayers could still be imaged in exfoliated samples.

    It is also shown that the reflectance/transmittance ratio increases quadratically with the number of graphene layers, which may allow for counting layer numbers and identifying wrinkles and folds in transferred samples.

  • 40.
    Rugeland, Patrik
    et al.
    RISE, Swedish ICT, Acreo, Fiber Optics.
    Sterner, Carola
    RISE, Swedish ICT, Acreo, Fiber Optics.
    Margulis, Walter
    RISE, Swedish ICT, Acreo, Fiber Optics.
    Visible light guidance in silica capillaries by antiresonant reflection2013In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 21, no 24, p. 29217-29222Article in journal (Refereed)
    Abstract [en]

    Hollow silica capillaries are examined as optical waveguides evaluating the antiresonant reflecting optical waveguide (ARROW) effect by sequentially reducing the wall thickness through etching and measuring the optical transmission. It is found that the periodicity of the transmission bands is proportional to the wall thickness and that the propagation loss is of the order of a few dB/m.

  • 41.
    Rugeland, Patrik
    et al.
    RISE, Swedish ICT, Acreo. KTH, Laserfysik.
    Tarasenko, Oleksandr
    RISE, Swedish ICT, Acreo.
    Margulis, Walter
    RISE, Swedish ICT, Acreo. KTH, Laserfysik.
    Nanosecond monolithic Mach-Zehnder fiber switch2012In: Optics Express, ISSN 1094-4087, Vol. 20, no 28, p. 29309-29318Article in journal (Refereed)
    Abstract [en]

    An electrically controlled high-speed all-fiber switch is investigated. It is based on a monolithic Mach-Zehnder interferometer using a Gemini fiber. The fiber is provided with internal electrodes for active control of the phase using high-voltage electrical pulses. The demonstrated switching speed is 20 ns. The monolithic design guarantees that the off- and on-states are attained simultaneously for a broad range of wavelengths (50 nm). The interferometer can be switched-off using a second electrode, providing a 15 ns long optical pulse.

  • 42.
    Sudirman, Azizahalhakim
    et al.
    RISE, Swedish ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Norin, Lars
    RISE, Swedish ICT, Acreo.
    Margulis, Walter
    RISE, Swedish ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Increased sensitivity in fiber-based spectroscopy using carbon-coated fiber2012In: Optics Express, ISSN 1094-4087, Vol. 20, no 27, p. 28049-28055Article in journal (Refereed)
    Abstract [en]

    Carbon-coated optical fibers are used here for reducing the luminescence background created by the primary-coating and thus increase the sensitivity of fiber-based spectroscopy systems. The 2-3 orders of magnitude signal-to-noise ratio improvement with standard telecom fibers is sufficient to allow for their use as Raman probes in the identification of organic solvents.

  • 43.
    Tarasenko, Oleksandr
    et al.
    RISE, Swedish ICT, Acreo.
    Margulis, Walter
    RISE, Swedish ICT, Acreo.
    The Effect of the Electrode Curvature on the Field in Internal Electrode Fibers2015In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 27, no 20, p. 2131-2133Article in journal (Refereed)
    Abstract [en]

    By solving the two-dimensional Poisson equation for fibers with circular internal electrodes, we show that the parallelplate approximation incurs significant error in the determination of the electric field applied to the fiber core. This also affects the value of χ(3) measured in electro-optical fibers. The exact solution of Poisson's equation is used to solve the field applied to the core of a photonic crystal fiber, where the many holes screen the field. A universal curve is derived to allow using the simplifying parallel plate approximation and correcting for the error in symmetric fibers with round holes.

  • 44.
    Tow, Kenny
    et al.
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Forsberg, Frans
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Carbon dioxide and carbon monoxide concentration monitoring for improved carbon capture and storage: From laboratory to a field test in a cement plant2019In: Proceedings of SPIE - The International Society for Optical Engineering, SPIE , 2019Conference paper (Refereed)
    Abstract [en]

    The cement industry is facing pressure to find technological solutions in reducing greenhouse gas emissions owing to the large amount of process emissions originating from the calcination of limestone. In this communication, an all-fibre gas monitoring system based on anti-resonant hollow-core fibres is proposed. An on-field test was performed in the harsh environment of a cement factory and it demonstrated the feasibility of using this system for low-concentration carbon dioxide and carbon monoxide monitoring in exhaust fumes

  • 45.
    Yang, Xiong
    et al.
    KTH Royal Institute of Technology, Sweden; Zhejiang University, China .
    Lindberg, Robert
    KTH Royal Institute of Technology, Sweden.
    Margulis, Walter
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Fröjdh, Krister
    Proximion AB, Sweden.
    Laurell, Fredrik
    KTH Royal Institute of Technology, Sweden.
    Rapid and continuously tunable narrow linewidth fiber source based on a SOA and a linearly chirped fiber Bragg grating2019In: Conference on Lasers and Electro-Optics OSA Technical Digest (Optical Society of America, 2019), paper SM1L.5, OSA - The Optical Society , 2019, article id SM1L.5Conference paper (Refereed)
    Abstract [en]

    We demonstrate a tunable narrow-linewidth laser based on a semiconductor optical amplifier and a linearly chirped FBG. High tuning resolution and small power variation over 40 nm tuning range were achieved by optimizing the drive current.

  • 46.
    Yu, Zhangwei
    et al.
    RISE, Swedish ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Malmström, Mikael
    RISE, Swedish ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Tarasenko, Oleksander
    RISE, Swedish ICT, Acreo.
    Margulis, Walter
    RISE, Swedish ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Laurell, Frederik
    KTH Royal Institute of Technology, Sweden.
    A Tunable All-Fiber Laser Based on a Stress-Optic Phase Modulator and a Chirped Fiber Bragg Grating2015In: Workshop on Specialty Optical Fibers and their Applications (WSOF 2015), 2015, article id WT4A.21Conference paper (Refereed)
    Abstract [en]

    A tunable single-wavelength Erbium-doped all-fiber laser was experimentally demonstrated. The tuning is obtained with a stress-optic phase modulator based on a twin-hole fiber and a chirped fiber Bragg grating in a medium birefringence fiber.

1 - 46 of 46
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