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  • 1.
    Amorebieta, Josu
    et al.
    University of the Basque Country, Spain.
    Pereira, Joao
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Durana, Gaizka
    University of the Basque Country, Spain.
    Franciscangelis, Carolina
    RISE Research Institutes of Sweden.
    Ortega-Gomez, Angel
    University of the Basque Country, Spain.
    Zubia, Joseba
    University of the Basque Country, Spain.
    Villatoro, Joel
    University of the Basque Country, Spain; Ikerbasque-Basque Foundation for Science, Spain.
    Margulis, Walter
    RISE Research Institutes of Sweden.
    Twin-core fiber sensor integrated in laser cavity2022Inngår i: Scientific Reports, E-ISSN 2045-2322, Vol. 12, nr 1, artikkel-id 11797Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, we report on a twin-core fiber sensor system that provides improved spectral efficiency, allows for multiplexing and gives low level of crosstalk. Pieces of the referred strongly coupled multicore fiber are used as sensors in a laser cavity incorporating a pulsed semiconductor optical amplifier (SOA). Each sensor has its unique cavity length and can be addressed individually by electrically matching the periodic gating of the SOA to the sensor’s cavity roundtrip time. The interrogator acts as a laser and provides a narrow spectrum with high signal-to-noise ratio. Furthermore, it allows distinguishing the response of individual sensors even in the case of overlapping spectra. Potentially, the number of interrogated sensors can be increased significantly, which is an appealing feature for multipoint sensing. © 2022, The Author(s).

  • 2.
    Amorebieta, Josu
    et al.
    University of the Basque Country, Spain.
    Pereira, Joao
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Franciscangelis, Carolina
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Durana, Gaizka
    University of the Basque Country, Spain.
    Zubia, Joseba
    University of the Basque Country, Spain.
    Villatoro, Joel
    University of the Basque Country, Spain.
    Margulis, Walter
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Carbon-coated fiber for optoelectronic strain and vibration sensing2024Inngår i: Optical fiber technology (Print), ISSN 1068-5200, E-ISSN 1095-9912, Vol. 85, artikkel-id 103794Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this article, we report on a carbon-coated optical fiber that is suitable to be used simultaneously as a transmission medium and as a sensor. It consists of a standard single mode fiber (SMF) sleeved in two layers of coating, which provide protection and isolation from external elements. The inner layer is made of carbon, whereas the outer is made of polymer. When the fiber is subjected to mechanical stress, the electrical resistance of the carbon layer changes accordingly. The voltage variations caused by the former can be measured with high accuracy and without interfering with the light propagating through the SMF. In this work, the feasibility of this operating principle is demonstrated in a low coherence Michelson interferometer in which electrical and optical signals were measured simultaneously and compared to each other. Results indicate that electrical measurements are as precise as the optical ones and with linear behavior, reaching a sensitivity of 1.582 mV/με and able to detect vibrations down to 100 mHz. © 2024 The Authors

    Fulltekst (pdf)
    fulltext
  • 3.
    Araujo, Jefferson
    et al.
    Pontifical Catholic University of Rio de Janeiro, Brazil.
    Reis, Andre
    Observatório Nacional, Brazil.
    Oliveira, Vanderlei
    Observatório Nacional, Brazil.
    Santos, Amanda
    University of California, US.
    Luz-Lima, Cleaneo
    Universidade Federal do Piauí, Brazil.
    Yokoyama, Elder
    University of Brasília, Brazil.
    Mendoza, Leonardo
    Universidade Estadual do Rio de Janeiro, Brazil.
    Pereira, Joao
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo.
    Bruno, Antonio
    Pontifical Catholic University of Rio de Janeiro, Brazil.
    Characterizing complex mineral structures in thin sections of geological samples with a scanning hall effect microscope2019Inngår i: Sensors, E-ISSN 1424-8220, Vol. 19, nr 7, artikkel-id 1636Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We improved a magnetic scanning microscope for measuring the magnetic properties of minerals in thin sections of geological samples at submillimeter scales. The microscope is comprised of a 200 µm diameter Hall sensor that is located at a distance of 142 µm from the sample; an electromagnet capable of applying up to 500 mT DC magnetic fields to the sample over a 40 mm diameter region; a second Hall sensor arranged in a gradiometric configuration to cancel the background signal applied by the electromagnet and reduce the overall noise in the system; a custom-designed electronics system to bias the sensors and allow adjustments to the background signal cancelation; and a scanning XY stage with micrometer resolution. Our system achieves a spatial resolution of 200 µm with a noise at 6.0 Hz of 300 nT rms /(Hz) 1/2 in an unshielded environment. The magnetic moment sensitivity is 1.3 × 10 −11 Am 2 . We successfully measured the representative magnetization of a geological sample using an alternative model that takes the sample geometry into account and identified different micrometric characteristics in the sample slice.

  • 4.
    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, Joao
    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 nanoparticles2016Inngår i: Optics InfoBase Conference Papers, 2016, artikkel-id LW3A.1Konferansepaper (Fagfellevurdert)
    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.

  • 5.
    Camara, Alexandre R.
    et al.
    Rio de Janeiro State University, Brazil; Pontifical Catholic University of Rio de Janeiro, Brazil.
    Pereira, Joao
    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 fiber2015Inngår i: Optics Express, E-ISSN 1094-4087, Vol. 23, nr 14, s. 18060-18069Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 6.
    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, Joao
    Pontifical Catholic University of Rio de Janeiro, Brazil.
    Margulis, Walter
    RISE., Swedish ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Pockels fibers by optical poling2015Inngår i: Workshop on Specialty Optical Fibers and their Applications 2015, 2015, artikkel-id WT4A.22Konferansepaper (Fagfellevurdert)
    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.

  • 7.
    Claesson, Åsa
    et al.
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Franciscangelis, Carolina
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Pereira, Joao
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Weldehawariat, Tedros
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Hey Tow, Kenny
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    FBG Applications in 25um Diameter Fibers2022Inngår i: Optics InfoBase Conference Papers, Optica Publishing Group (formerly OSA) , 2022Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Ultrathin 25μm optical fibers with FBG sensors are manufactured and used as vibration sensors in glass-fiber reinforced composites. The use of ultrathin fibers is discussed, and their manufacture is described. © 2022 The Authors.

  • 8.
    Etcheverry, Sebastian
    et al.
    RISE - Research Institutes of Sweden (2017-2019), 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
    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 (2017-2019), ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Fontana, Jake
    Naval Research Laboratory, USA.
    Microsecond switching of plasmonic nanorods in an all-fiber optofluidic component2017Inngår i: Optica, E-ISSN 2334-2536, Vol. 4, nr 8, s. 864-870Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 9.
    Falk, Krister
    RISE - Research Institutes of Sweden (2017-2019), Samhällsbyggnad, Byggteknik.
    Bozic, Katarina
    OBOS AB, Sweden.
    Nyberg, Josefin
    Tengbomgruppen AB, Sweden.
    Pereira, Joao
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara. Tengbomgruppen AB, Sweden.
    Janerö, Kirsi
    RISE - Research Institutes of Sweden (2017-2019), Samhällsbyggnad, Byggteknik.
    Hansén, Magnus
    RISE - Research Institutes of Sweden (2017-2019), Samhällsbyggnad, Byggteknik.
    Kartläggning av marknadens flexväggar för det anpassningsbara boendet2017Rapport (Annet vitenskapelig)
    Fulltekst (pdf)
    fulltext
  • 10.
    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 (2017-2019), ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Tarasenko, Oleksandr
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo.
    Norin, Lars
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo.
    Margulis, Walter
    RISE - Research Institutes of Sweden (2017-2019), 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 fibers2018Inngår i: Optics InfoBase Conference Papers, 2018Konferansepaper (Fagfellevurdert)
    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. 

  • 11.
    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 (2017-2019), ICT, Acreo.
    Tarasenko, Oleksandr
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo.
    Norin, Lars
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo.
    Margulis, Walter
    RISE - Research Institutes of Sweden (2017-2019), 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 modulators2019Inngår i: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 37, nr 18, s. 4567-4572Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 12.
    Hey Tow, Kenny
    et al.
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Pereira, Joao
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Lindblom, Magnus
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Fernández-Ruiz, Maria
    University of Alcalá, Spain.
    Martins, Hugo F
    Daza de Valdés Institute of Optics, Spain.
    Rossi, Matteo
    Lund University, Sweden.
    Nilsson, Siw
    LKAB, Sweden.
    van den Berg, Harald
    LKAB, Sweden.
    Monitoring mining induced seismicity using optical fibre sensors during mine exploitation2023Inngår i: Proc SPIE Int Soc Opt Eng, SPIE , 2023, Vol. 643, artikkel-id 1264324Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Fibre-optic based sensing technologies are becoming popular in the field of geophysics since enable long range and high spatial resolution acoustic measurements. In this work, we present preliminary results obtained using quasi-distributed Fibre-Bragg grating sensing and Distributed Acoustic Sensing (DAS) to monitor seismic activities in an operational underground mine. 12 FBGs and 800 metres of fiber optic cable was installed in the tunnel lining an operational mine and recorded mine seismicity such as production blasts and a small seismic activity of magnitude 1.41 in September 2022. 

  • 13.
    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 (2017-2019), ICT, Acreo.
    Margulis, Walter
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo.
    Martin-Lopez, Sonia
    University of Alcala, Spain.
    Gonzalez-Herraez, Miguel
    University of Alcala, Spain.
    Fiber-based distributed bolometry2019Inngår i: Optics Express, E-ISSN 1094-4087, Vol. 27, nr 4, s. 4317-4328Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 14.
    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 (2017-2019), ICT, Acreo.
    Margulis, Walter
    RISE - Research Institutes of Sweden (2017-2019), 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 reflectometry2018Inngår i: Optics InfoBase Conference Papers, 2018Konferansepaper (Fagfellevurdert)
    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. 

  • 15.
    Magalhães, Regina
    et al.
    University of Porto, Portugal.
    Pereira, Joao
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Garcia-Ruiz, Andres
    University of Alcalá, Spain.
    Margulis, Walter
    RISE - Research Institutes of Sweden (2017-2019), 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 φoTDR2019Inngår i: Proceedings of SPIE - The International Society for Optical Engineering, SPIE , 2019Konferansepaper (Fagfellevurdert)
    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.

  • 16.
    Magalhães, Regina
    et al.
    University de Alcalá, Spain.
    Pereira, Joao
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Tarasenko, Oleksandr
    RISE Research Institutes of Sweden.
    Martin-Lopez, Sonia
    University de Alcalá, Spain.
    González-Herráez, Miguel
    University de Alcalá, Spain.
    Margulis, Walter
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Fidalgo Martins, Hugo
    CSIS Consejo Superior de Investigaciones Científicas, Spain.
    Towards Distributed Measurements of Electric Fields Using Optical Fibers: Proposal and Proof-Of-Concept Experiment.2020Inngår i: Sensors, E-ISSN 1424-8220, Vol. 20, nr 16, artikkel-id E4461Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nowadays there is an increasing demand for the cost-effective monitoring of potential threats to the integrity of high-voltage networks and electric power infrastructures. Optical fiber sensors are a particularly interesting solution for applications in these environments, due to their low cost and positive intrinsic features, including small size and weight, dielectric properties, and invulnerability to electromagnetic interference (EMI). However, due precisely to their intrinsic EMI-immune nature, the development of a distributed optical fiber sensing solution for the detection of partial discharges and external electrical fields is in principle very challenging. Here, we propose a method to exploit the third-order and second-order nonlinear effects in silica fibers, as a means to achieve highly sensitive distributed measurements of external electrical fields in real time. By monitoring the electric-field-induced variations in the refractive index using a highly sensitive Rayleigh-based CP-φOTDR scheme, we demonstrate the distributed detection of Kerr and Pockels electro-optic effects, and how those can assign a new sensing dimension to optical fibers, transducing external electric fields into visible minute disturbances in the guided light. The proposed sensing configuration, electro-optical time domain reflectometry, is validated both theoretically and experimentally, showing experimental second-order and third-order nonlinear coefficients, respectively, of χ(2) ~ 0.27 × 10-12 m/V and χ(3) ~ 2.5 × 10-22 m2/V2 for silica fibers.

  • 17.
    Pereira, Joao
    et al.
    RISE - Research Institutes of Sweden (2017-2019), 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 (2017-2019), ICT, Acreo.
    Margulis, Walter
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Linear electro-optical effect in silica fibers poled with ultraviolet lamp2019Inngår i: Optics Express, E-ISSN 1094-4087, Vol. 27, nr 10, s. 14893-14902Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 18.
    Pereira, Joao
    et al.
    RISE - Research Institutes of Sweden (2017-2019), 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 (2017-2019), ICT, Acreo.
    Margulis, Walter
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Poling optical fibers with UV lamp2019Inngår i: Conference on Lasers and Electro-Optics OSA Technical Digest (Optical Society of America, 2019), paper SM2L.5, OSA - The Optical Society , 2019, artikkel-id SM2L.5Konferansepaper (Fagfellevurdert)
    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.

  • 19.
    Pereira, Joao
    et al.
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara. KTH Royal Institute of Technology, Sweden.
    Claesson, Åsa
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Laurell, F.
    KTH Royal Institute of Technology, Sweden.
    Tarasenko, Oleksander
    RISE Research Institutes of Sweden.
    Margulis, Walter
    RISE Research Institutes of Sweden. KTH Royal Institute of Technology, Sweden.
    Poling optical fibers with electrical corona discharge2021Inngår i: Optics InfoBase Conference Papers, The Optical Society , 2021Konferansepaper (Fagfellevurdert)
  • 20.
    Pereira, Joao
    et al.
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara. PUC-Rio, Brazil.
    Gouvea, Paula M. P.
    PUC-Rio, Brazil.
    Braga, Arthur M. B.
    PUC-Rio, Brazil.
    Carvalho, Isabel
    PUC-Rio, Brazil.
    Bruno, Antonio C.
    PUC-Rio, Brazil.
    Fabry-Perot Cavity Optimization for Absolute Strain Sensing Using Finite Element Analysis2023Inngår i: SENSORS, Vol. 23, nr 21, artikkel-id 8785Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The finite element method (FEM) was used to investigate the optical-mechanical behavior of a Fabry-Perot Interferometer (FPI) composed of a capillary segment spliced between two sections of standard optical fiber. The developed FEM model was validated by comparing it with theory and with previously published experimental data. The model was then used to show that the absolute strain on the host substrate is usually smaller than the strain measurement obtained with the sensor. Finally, the FEM model was used to propose a cavity geometry that can be produced with repeatability and that yields the correct absolute strain experienced by the host substrate, without requiring previous strain calibration.

  • 21.
    Pereira, Joao
    et al.
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara. KTH Royal Institute of Technology, Sweden.
    Grüner-Nielsen, L.
    DTU Technical University of Denmark, Denmark; Danish Optical Fiber Innovation, Denmark.
    Rottwitt, K.
    DTU Technical University of Denmark, Denmark.
    Laurell, F.
    KTH Royal Institute of Technology, Sweden.
    Margulis, W.
    KTH Royal Institute of Technology, Sweden; Fiberactivity Ltda, Brazil.
    Electrooptic Intermodal Interference in Silicate Fibers with Internal Electrodes2022Inngår i: Optics InfoBase Conference Papers, Optica Publishing Group (formerly OSA) , 2022, artikkel-id STu5P.1Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The electrooptic effect is used in a few-mode fiber to control intermodal interference. The fiber has internal electrodes and is poled to increase its electrooptic coefficient. The response time is in the nanosecond range. © Optica Publishing Group 2022, © 2022 The Author(s)

  • 22.
    Pereira, Joao
    et al.
    KTH Royal Institute of Technology, Sweden.
    Grüner-Nielsen, Lars
    DTU Technical University of Denmark, Denmark.
    Rottwitt, Karsten
    DTU Technical University of Denmark, Denmark.
    Town, Graham
    Macquarie University, Australia.
    Laurell, Fredrik
    KTH Royal Institute of Technology, Sweden.
    Margulis, Walter
    KTH Royal Institute of Technology, Sweden; Fiberactivity Ltda, Brazil.
    Electrooptic control of the modal distribution in a silicate fiber2022Inngår i: Optics Express, E-ISSN 1094-4087, Vol. 30, nr 8, s. 12474-12483Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate the use of the electrooptic effect to control the propagation constant of the guided modes in silicate few mode fibers with internal electrodes. The electrooptic effect induces a perturbation of the fiber's refractive index profile that controls intermodal interference. To increase the electrooptic effect the silicate fibers are poled. The response time is in the nanosecond range. 

  • 23.
    Pereira, Joao
    et al.
    RISE - Research Institutes of Sweden (2017-2019), 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 (2017-2019), ICT, Acreo.
    Margulis, Walter
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    High-voltage fiber sensor based on fiber Bragg grating in poled fiber2019Inngår i: Proceedings of SPIE - The International Society for Optical Engineering, SPIE , 2019Konferansepaper (Fagfellevurdert)
    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..

  • 24.
    Pereira, Joao
    et al.
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara. KTH Royal Institute of Technology, Sweden.
    Tarasenko, Oleksander
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Claesson, Åsa
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Laurell, Fredrik
    KTH Royal Institute of Technology, Sweden.
    Margulis, Walter
    KTH Royal Institute of Technology, Sweden; Fiberactivity Ltda, Brazil.
    Optical poling by means of electrical corona discharge2022Inngår i: Optics Express, E-ISSN 1094-4087, Vol. 30, nr 12, s. 20605-20613Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electrical corona discharge is employed in this work to deposit ions on the surface of an optical fiber, creating a strong electric field that is used for poling. Green laser light propagating in the core frees photocarriers that are displaced by the poling field. The technique presented can induce a higher optical nonlinearity than previously obtained in traditional optical poling with internal metal electrodes. To date, a maximum second order nonlinearity 0.13 pm/V has been achieved for a 15 kV corona discharge bias. 

  • 25.
    Srivastava, Anubhav
    et al.
    University of Naples, Italy.
    Esposito, F.
    University of Naples, Italy.
    Pereira, Joao
    RISE Research Institutes of Sweden, Digitala system, Smart hårdvara.
    Campopiano, S.
    University of Naples, Italy.
    Iadicicco, A.
    University of Naples, Italy.
    Fabrication and characterization of arc-induced long period gratings in optical fibers with micro-channels2020Inngår i: Proceedings of IEEE Sensors, Institute of Electrical and Electronics Engineers Inc. , 2020Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this work, we report about the fabrication and characterization of long period gratings (LPG) in so-called side-hole fibers (SHF). They have a different number (one, two, and four) of micro-channels in the cladding region, developing along the longitudinal direction of the optical fiber. For the first time, LPG inscription was performed by electric discharge technique in these fibers, resulting in devices with good spectral features, i.e. deep and narrow attenuation bands. The gratings were characterized in terms of response to surrounding refractive index, temperature, and strain, demonstrating the effectiveness of the fabrication process. The final aim is to provide a flexible sensing platform for the development of micro-fluidic devices for different applications.

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