1,720,975 research outputs found
Simple And Temperature-insensitive Pressure Sensing Based On A Hollow-core Photonic Crystal Fiber
Full text linkThe sensitivity to pressure of lossy air-guided modes in a commercial hollow-core photonic crystal fiber was experimentally exploited to develop a novel pressure sensor. The transmission of these modes was directly modulated by the measurand, which makes the interrogation system very simple. Using a supercontinuum source, these specific modes were identified within the visible spectral range and correspond to narrow transmission windows well away from the fiber's main bandgap, centered around 1550 nm. The origin of these windows is being investigated but is likely to be related to cladding bandgaps. One of these windows, around 633 nm, was used for the analysis presented in this paper. An attenuation increase was observed when pressure was applied to a ∼3-cm long cell, which was traversed by the fiber. The attenuation reached 5 dB with 300kgf/cm2 gauge pressure. The transmission was found to be insensitive to temperature up to 100°C, which is a highly attractive feature for sensing applications. It was also found that much higher sensitivities (a few dB attenuation with ∼0.5kgf/cm2 gauge pressure) could be obtained when pressure was internally applied to the fiber microstructure. This fact allows for the construction of sensors with a wide range of sensitivities, which can, thus, suit different applications. Transmission within the infrared bandgap was insensitive to pressure and can serve as a reference. © American Institute of Physics.1055129132Knight, J.C., (2003) Nature, 424, pp. 847-851Alkeskjold, T.T., Lægsgaard, J., Bjarklev, A., Hermann, D.S., Broeng, J., Li, J., Gauza, S., Wu, S.-T., (2006) Appl. Opt, 45, pp. 2261-2264Cordeiro, C.M.B., de Matos, C.J.S., dos Santos, E.M., Bozolan, A., Ong, J.S.K., Facincani, T., Chesini, G., Brito Cruz, C.H., (2007) Meas. Sci. Technol, 18, pp. 3075-3081Jensen, J.B., Pedersen, L.H., Hoiby, P.E., Nielsen, L.B., Hansen, T.P., Folkenberg, J.R., Riishede, J., Bjarklev, A., (2004) Opt. Lett, 29, pp. 1974-1976Krohn, D.A., Pressure Sensors (2000) Fiber Optic Sensors, pp. 143-151. , Research Triangle Park: Instrument Society of AmericaXu, M.G., Reekie, L., Chow, Y.T., Dakin, J.P., (1993) Electron. Let, 29, pp. 398-399Hsu, Y.S., Wang, L., Fung Liu, W., Chiang, Y.J., (2006) IEEE Photon. Technol. Let, 18, pp. 874-876Nasilowski, T., (2005) Appl. Phys. B, 81, pp. 325-331Bock, W.J., Chen, J., Eftimov, T., Urbanczyk, W., (2006) IEEE T. Instrum. Meas, 55, pp. 874-876Shinde, Y.S., Gahir, H.K., (2008) IEEE Photon. Technol. Let, 20, pp. 279-28
Sealed Liquid-core Photonic Crystal Fibers For Practical Nonlinear Optics, Nanophotonics And Sensing Applications
No full textPhotonic crystal fibers have been the subject of several studies for potential application in areas such as sensing, nonlinear optics, telecommunication and nanophotonics. Many applications are enabled by the possibility of selectively inserting gases, liquids, polymers and colloids into the internal microstructure, which results in efficient interaction with the guided light, allowing for the development of, e.g., sensitive chemical sensors also, the insertion of materials can be exploited to modify waveguide characteristics such as modal field distributions, the nonlinear coefficient and the chromatic dispersion. Experimentally, the insertion of liquids is particularly straightforward and enables many of the envisaged studies. However, evaporation is an important limiting issue, which ultimately prevents the realization long-term practical applications. Also, in some cases contact of the liquid with the external environment may degrade its properties. To address these issues, we experimentally demonstrate a new technique to selectively seal a liquid-filled hole of a photonic crystal fiber. The characteristics of the sealed fibers remained stable for at least a few weeks. Two experiments were, then, carried out to demonstrate the potential of the technique. In the first experiment, a water-core photonic crystal fiber was used for supercontinuum generation, with the generated spectrum not showing degradation over time. In the second experiment, a colloid of CdSe nanoparticles was inserted into the core of a fiber and stable photoluminescence was observed. © 2010 SPIE.7839Russell, P.St.J., Photonic crystal fibers (2006) Journal of Lightwave Technology, 24 (12), pp. 4729-4749Fini, J.M., Microstructure fibres for optical sensing in gases and liquids (2004) Measurement Science and Technology, 15 (6), pp. 1120-1128. , DOI 10.1088/0957-0233/15/6/011, PII S0957023304753850Yiou, S., Delaye, P., Rouvie, A., Chinaud, J., Frey, R., Roosen, G., Viale, P., Blondy, J.-M., Stimulated Raman scattering in an ethanol core microstructured optical fiber (2005) Optics Express, 13 (12), pp. 4786-4791. , http://www.opticsexpress.org/view_file.cfm?doc= %24%29L%27%26KP%20%20%0A&id=%25%28%2C%3B%28J%3C0%20%0A, DOI 10.1364/OPEX.13.004786Bozolan, A., De Matos, C.J.S., Cordeiro, C.M.B., Santos, E.M., Travers, J., Supercontinuum generation in a water-core photonic crystal fiber (2008) Optics Express, 16 (13), pp. 9671-9676Meissner, K.E., Holton, C., Spillman Jr., W.B., Optical characterization of quantum dots entrained in microstructured optical fibers (2005) Physica E: Low-Dimensional Systems and Nanostructures, 26 (1-4), pp. 377-381. , DOI 10.1016/j.physe.2004.08.008, PII S138694770400431XOng, J.S.K., Facincani, De Matos, C.J.S., Evaporation in water-core photonic crystal-fibers (2008) 1 st Workhop on Specialty Optical Fibers and Their Applications, pp. 152-154. , São Pedro, BrazilHuang, Y., Xu, Y., Yariv, A., Fabrication of functional microstructured optical fibers through a selective-filling technique (2004) Applied Physics Letters, 85 (22), pp. 5182-5184. , DOI 10.1063/1.1828593, 3Witkowska, A., Lai, K., Leon-Saval, S.G., Wadsworth, W.J., Birks, T.A., All-fiber anamorphic core-shape transitions (2006) Optics Letters, 31 (18), pp. 2672-2674. , DOI 10.1364/OL.31.002672Walker, G.W., Sundar, V.C., Rudzinski, C.M., Wun, A.W., Bawendi, M.G., Nocera, D.G., Quantum-dot optical temperature probes (2003) Applied Physics Letters, 83 (17), pp. 3555-3557Bravo, J., Encapsulated quantum dot nanofilms inside hollow core optical fibers for temperature measurement (2008) IEEE Sensors Journal, 8 (7), pp. 1368-137
Selectively Coupling Core Pairs In Multicore Photonic Crystal Fibers: Optical Couplers, Filters And Polarization Splitters For Space- Divisionmultiplexed Transmission Systems
No full textSelective coupling a single pair of cores in a photonic crystal fiber with multiple, initially decoupled, cores is demonstrated through the use of a technique to locally post-process the fiber cross section. Coupling occurs when the hole between the selected core pair is collapsed over a short fiber section, which is accomplished by heating the section while the hole is submitted to an air pressure that is lower than that applied to all other holes in the microstructure. The demonstrated couplers present an estimated insertion loss of ∼1 dB and exhibit spectral modulations with a depth of up to 18 dB and a high polarization sensitivity that can be exploited for polarization splitting or filtering in space-division-multiplexed optical interconnection and telecommunication links. © 2012 Optical Society of America.20272898128988Gauden, D., Mechin, D., Vaudry, C., Yvernault, P., Pureur, D., Variable optical attenuator based on thermally tuned Mach-Zehnder interferometer within a twin core fiber (2004) Opt. Commun., 231 (1-6), pp. 213-216Kim, B., Kim, T.-H., Cui, L., Chung, Y., Twin core photonic crystal fiber for in-line Mach-Zehnder interferometric sensing applications (2009) Opt. Express, 17 (18), pp. 15502-15507Harhira, A., Lapointe, J., Kashyap, R., A Simple Bend Sensor Using a Twin Core Fiber Mach-Zehnder Interferometer (2010) Latin America Optics and Photonics Conference, OSA Technical Digest (CD), , Optical Society of America, paper TuF3Zhou, A., Li, G., Zhang, Y., Wang, Y., Guan, C., Yang, J., Yuan, L., Asymmetrical twin-core fiber based michelson interferometer for refractive index sensing (2011) J. Lightwave Technol., 29 (19), pp. 2985-2991Michaille, L., Taylor, D.M., Bennett, C.R., Shepherd, T.J., Ward, B.G., Characteristics of a Q-switched multicore photonic crystal fiber laser with a very large mode field area (2008) Opt. Lett., 33 (1), pp. 71-73Fang, X.-H., Hu, M.-L., Liu, B.-W., Chai, L., Wang, C.-Y., Zheltikov, A.M., Generation of 150 MW, 110 fs pulses by phase-locked amplification in multicore photonic crystal fiber (2010) Opt. Lett., 35 (14), pp. 2326-2328Fang, X.-H., Hu, M.-L., Huang, L.-L., Chai, L., Dai, N.-L., Li, J.-Y., Tashchilina, A.Y., Wang, C.-Y., Multiwatt octave-spanning supercontinuum generation in multicore photonic-crystal fiber (2012) Opt. Lett., 37 (12), pp. 2292-2294Modotto, D., Manili, G., Minoni, U., Wabnitz, S., De Angelis, C., Town, G., Tonello, A., Couderc, V., Ge-doped microstructured multicore fiber for customizable supercontinuum generation (2011) IEEE Photon. J., 3 (6), pp. 1149-1156Reichenbach, K.L., Xu, C., Numerical analysis of light propagation in image fibers or coherent fiber bundles (2007) Opt. Express, 15 (5), pp. 2151-2165Hirano, M., Future of transmission fiber (2011) IEEE Photon. J., 3 (2), pp. 316-319Zhu, B., Taunay, T.F., Yan, M.F., Fishteyn, M., Oulundsen, G., Vaidya, D., 70-Gb/s multicore multimode fiber transmissions for optical data links (2010) IEEE Photon. Technol. Lett., 22, pp. 1647-1649Zhu, B., Fini, J.M., Yan, M.F., Liu, X., Chandrasekhar, S., Taunay, T.F., Fishteyn, M., Dimarcello, F.V., High-capacity space-division-multiplexed DWDM transmissions using multicore fiber (2012) J. Lightwave Technol., 30 (4), pp. 486-492Lee, B.G., Kuchta, D.M., Doany, F.E., Schow, C.L., Pepeljugoski, P., Baks, C., Taunay, T.F., Li, N., End-to-End Multicore Multimode Fiber Optic Link Operating up to 120 Gb/s (2012) J. Lightwave Technol., 30 (6), pp. 886-892Zhu, B., Taunay, T.F., Yan, M.F., Fini, J.M., Fishteyn, M., Monberg, E.M., Dimarcello, F.V., Seven-core multicore fiber transmissions for passive optical network (2010) Opt. Express, 18 (11), pp. 11117-11122Rosinski, B., Chi, J.W.D., Grosso, P., Le Bihan, J., Multichannel transmission of a multicore fiber coupled with vertical-cavity surface-emitting lasers (1999) J. Lightwave Technol., 17 (5), pp. 807-810Taylor, D.M., Bennett, C.R., Shepherd, T.J., Michaille, L.F., Nielsen, M.D., Simonsen, H.R., Demonstration of multi-core photonic crystal fibre in an optical interconnect (2006) Electron. Lett., 42 (6), pp. 331-331Mangan, B.J., Knight, J.C., Birks, T.A., St. Russell, P.J., Greenaway, A.H., Experimental study of dualcore photonic crystal fibre (2000) Electron. Lett., 36 (16), pp. 1358-1359Mukasa, K., Imamura, K., Takahashi, M., Yagi, T., Development of novel fibers for telecoms application (2010) Opt. Fiber Technol., 16 (6), pp. 367-377Saitoh, K., Sato, Y., Koshiba, M., Coupling characteristics of dual-core photonic crystal fiber couplers (2003) Opt. Express, 11 (24), pp. 3188-3195Yan, Y., Toulouse, J., Nonlinear inter-core coupling in triple-core photonic crystal fibers (2009) Opt. Express, 17 (22), pp. 20272-20281Saitoh, F., Saitoh, K., Koshiba, M., A design method of a fiber-based mode multi/demultiplexer for modedivision multiplexing (2010) Opt. Express, 18 (5), pp. 4709-4716Yuan, L., Liu, Z., Yang, J., Guan, C., Bitapered fiber coupling characteristics between single-mode singlecore fiber and single-mode multicore fiber (2008) Appl. Opt., 47 (18), pp. 3307-3312Witkowska, A., Lai, K., Leon-Saval, S.G., Wadsworth, W.J., Birks, T.A., All-fiber anamorphic core-shape transitions (2006) Opt. Lett., 31 (18), pp. 2672-2674Lai, K., Leon-Saval, S.G., Witkowska, A., Wadsworth, W.J., Birks, T.A., Wavelength-independent all-fiber mode converters (2007) Opt. Lett., 32 (4), pp. 328-330Gerosa, R.M., Spadoti, D.H., Menezes, L.S., De Matos, C.J., In-fiber modal Mach-Zehnder interferometer based on the locally post-processed core of a photonic crystal fiber (2011) Opt. Express, 19 (4), pp. 3124-3129Gerosa, R.M., Biazoli, C.R., Cordeiro, C.M.B., De Matos, C.J.S., Post-processing multicore photonic crystal fibers for locally coupling selected core pairs (2011) CLEO: 2011 - Laser Applications to Photonic Applications, OSA Technical Digest (CD), , Optical Society of America, paper JWA39Gerosa, R.M., Spadoti, D.H., De Matos, C.J.S., Menezes, L.S., Franco, M.A., Efficient and short-range light coupling to index-matched liquid-filled hole in a solid-core photonic crystal fiber (2011) Opt. Express, 19 (24), pp. 24687-2469
Theoretical And Experimental Study Of Supercontinuum Generation In A Water-core Pcf
No full textPhotonic crystal fibers have been the subject of several studies for potential applications in areas such as telecommunications, sensing, metrology, biology, medicine and spectroscopy. These fibers have a number of unique features owing to their geometric structure, which consists of a matrix of regular holes that travels along its longitudinal axis. This design allows the selective insertion of materials such as gas and liquids, which interact efficiently with the guided modes. The insertion of materials can also be explored to introduce a new degree of freedom to control the properties of waveguide, by modifying modal features such as nonlinear coefficient and dispersion. Such control may, in some cases, contribute to increase the efficiency of nonlinear effects, enabling the creation of a supercontinumm spectrum. In this work we compare results obtained both experimentally and numerically of supercontinuum generation in a distilled water-core photonic crystal fiber. The results indicate the importance of setting the pump close to the zero dispersion region of the material so that a broad spectrum can be obtained. Improved agreement between experiments and simulations requires a better degree of experimental detail to be incorporated into the theoretical model, which will be the objective of future studies and work. © American Institute of Physics.1055155158Alfano, R.R., (2006) The supercontinuum laser source: Fundamentals with updated references, , 2nd ed, Springer: New YorkZhang, R., Teipel, J., Giessen, H., Theoretical design of a liquid-core photonic crystal fiber for supercontinuum generation (2006) Opt. Express, 14 (15), pp. 6800-6812. , JulGomes, A.S.L., Falcão-Filho, E.L., de Araújo, C.B., Thermally managed eclipse Z-scan (2007) Opt Express, 15 (4), pp. 1712-1717. , FebBozolan, A., de Matos, C.J.S., Cordeiro, C.M.B., dos Santos, E.M., Travers, J., Supercontinuum generation in a water-core photonic crystal fiber (2008) Opt Express, 16 (13), pp. 9671-9676. , JunWeber, M.J., (2003) Handbook of Optical Materials, pp. 383-384. , CRC Press: Boca Raton, ppMartins, E.R., Spadoti, D.H., Romero, M.A., Borges, B.H.V., Theoretical analyses of supercontinuum generation in a highly birefringent D-shaped microstructured optical fiber (2007) Opt. Express, 15 (22), pp. 14335-14347. , OctSanta, I., Foggi, P., Righini, R., Williams, J.H., Time-resolved optical Kerr effect measurements in aqueous ionic solutions (1994) J. Phys. Chem, 98, pp. 7692-770
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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