1,720,975 research outputs found
Dysprosium doped Ga:La:S glass for an efficient optical fibre amplifier operating at 1.3µm
No full textWe present experimental results which indicate that a Dy3+-doped Ga:La:S glass fibre amplifier may be operated efficiently at 1.3µm with an optimum device length significantly shorter than a comparable Pr3+-doped one. Moreover, the efficiency exceeds that obtained from the Pr3+-doped ZBLAN devices currently available
Application of a modified Judd-Ofelt theory to praseodymium doped fluoride glasses
No full textUsing the original Judd-Ofelt theory and a more recent modified Judd-Ofelt theory, the radiative properties of praseodymium in a series of halide glasses are predicted. Experimental and measured oscillator strengths are presented and Judd-Ofelt parameters are determined by both methods for all glasses. The calculated radiative lifetimes are compared with the experimentally measured values for the 1D2 energy level and the suitability of the two models are compared. Results show that the modified theory provides better agreement with the experimentally measured lifetimes for the 1D2 transition
Efficient Second-harmonic Generation In Praseodymium-doped Ga : La : S Glass For 1.3-μm Optical Fiber Amplifiers
No full textEfficient second-harmonic generation in praseodymium-doped gallium-lanthanum-sulphide glasses for optical fiber amplifiers around 1.3 μm is experimentally investigated. The Pr 3+-doped Ga : La : S glass samples were pumped by Nd : YAG laser pulses at 1.319 μm and 1.064 μm and generated frequency doubled light at 660 nm and 532 nm, respectively, with conversion efficiencies as high as 0.02%. Frequency doubling in praseodymium-free Ga : La : S glass samples was also observed.86821823Kumta, P.N., Risbud, S.H., Rare-earth chalcogenides an emerging class of optical materials (1994) J. Mater. Sci., 29, pp. 1135-1158Hewak, D.W., Deol, R.S., Wang, J., Wylangowski, G., Medeiros Neto, J.A., Samson, B., Laming, R.I., Baro, M.D., Low-phonon-energy glasses for efficient 1.3 μm optical fiber amplifiers (1993) Elect. Lett., 29, pp. 237-238Hewak, D.W., Medeiros Neto, J.A., Samson, B., Brown, R.S., Jedrzejewski, K.P., Wang, J., Taylor, E., Payne, D.N., Quantum-efficiency of praseodymium doped Ga:La:S glass for 1.3 μm optical fiber amplifiers (1994) IEEE Photon. Technol. Lett., 6, pp. 609-612Medeiros Neto, J.A., Taylor, E.R., Samson, B.N., Wang, J., Hewak, D.W., Laming, R.I., Payne, D.N., Hanney, R., The application of Ga:La:S-based glass for optical amplification at 1.3 μm (1995) J. Non-Cryst. Sol., 184, pp. 292-296Hewak, D.W., Samson, B.N., Medeiros Neto, J.A., Laming, R.I., Payne, D.N., Emission at 1.3 μm from dysprosium-doped Ga:La:S glass (1994) Elect. Lett., 30, pp. 968-970Samson, B.N., Medeiros Neto, J.A., Laming, R.I., Hewak, D.W., Dysprosium doped Ga:La:S glass for an efficient optical fiber amplifier operating at 1.3 μm (1994) Electron. Lett., 30, pp. 1617-1619Flahaut, J., Guittard, M., Loireau-Lozach, A.M., Rare-earth sulphide and oxysulphide glasses (1979) Glass Technol., 24, pp. 149-156MacDonald, R.L., Lawandy, N.M., Optically encoded phase-matched second-harmonic generation in semiconductor-microcrystallite-doped glasses (1991) J. Opt. Soc. Amer. B, 8, pp. 1307-1317MacDonald, R.L., Lawandy, N.M., Efficient second-harmonic generation into the UV by using optically rncoded dilicate glasses (1993) Opt. Lett., 18, pp. 595-597Discroll, T.J., Lawandy, N.M., Optically encoded second-harmonic generation in bulk silica-based glasses (1994) J. Opt. Soc. Amer. B, 11, pp. 355-371Osterberg, U., Margulis, W., Dye laser pumped by Nd:YAG laser pulses frequency doubled in a glass optical fiber (1986) Opt. Lett., 11, pp. 516-518Osterberg, U., Margulis, W., Experimental studies on efficient doubling in glass optical fiber (1987) Opt. Lett., 12, pp. 57-59Stolen, R.H., Tom, H.W.K., Self-organized phase-matched harmonic generation in optical fibers (1987) Opt. Lett., 12, pp. 585-587Krol, D.M., Giovanni, D.J., Pleibel, W., Stolen, R.H., Observation of resonant enhancement of photoinduced second-harmonic generation in Tm-doped aluminosilicate glass fibers (1993) Opt. Lett., 18, pp. 1220-1222Thogersen, J., Mark, J., Third-harmonic generation in standard and erbium-doped fibers (1994) Opt. Commun., 110, pp. 435-444Hickmann, J.M., Gouveia, E.A., Gouveia-Neto, A.S., Dini, D.C., Celaschi, S., Two-photon-resonant photoinduced second-harmonic generation in Er 3+-doped germano-aluminosilicate optical fibers pumped at 1.319 μm (1994) Opt. Lett., 19, pp. 1726-1728Hickmann, J.M., Gouveia, E.A., Gouveia-Neto, A.S., Dini, D.C., Celaschi, S., Enhancement of third-harmonic blue-violet light at 440 nm by erbium ions in Er 3+-GeO 2-doped silica monomode optical fibers pumped at 1.319 μm (1995) Opt. Lett., 20, pp. 1692-169
Emission at 1.3 microns from dysprosium-doped Ga:La:S glass
No full textThe potential for optical amplification at 1.3 µm is demonstrated in a dysprosium-doped gallium-lanthanum-sulphide based glass. Lifetimes of 59µs are observed for the 6H9/2 - 6H15/2 transition for which the emission peaks at 1.32µm. A radiative lifetime of 203µs is calculated by a Judd-Ofelt analysis, indicating a total radiative quantum efficiency of 29%. A pump absorption cross-section 20 times greater than Pr3+ suggests that shorter fibre devices may be possible
The application of Ga:La:S-based glasses for optical amplification at 1.3µm
No full textThe optical properties of praseodymium-doped low-phonon energy glasses have recently attracted considerable attention for their potential application as a 1.3µm Pr3+-doped optical fibre amplifier. Sulphide glasses based on Ga2S3 and La2S3 are amongst the lowest phonon energy glass which are suitable for this application, with quantum efficiencies exceeding 50% currently measured on bulk samples in our laboratory. The purpose of this paper is to describe the thermal, optical and spectroscopic properties of Pr3+-doped sulphide based glasses and report on progress to date in achievement of a Pr3+-doped sulphide based fibre
High Verdet Constant Ga:s:la:o Chalcogenide Glasses For Magneto-optical Devices
Full text linkThe magneto-optical rotation at room temperature was measured for three Ga:S:La:O chalcogenide glasses at several laser lines in the visible. The first sample was a binary system constituted by 70 mol % Ga2S3 and 30 mol % La2O3, whereas in the second and third ones the lanthanum oxide was partially substituted by lanthanum sulfide, keeping the amount of gallium sulfide fixed. A pulsed magnetic field between 50 and 80 kG was used for the Faraday rotation measurements. The Verdet constant for one of the ternary samples was found to be as high as 0.205 min G-1 cm-1 at 543 nm, indicating that these chalcogenide glasses are very promising for magneto-optical applications. The data for each sample were fitted using the expected analytical expression for the magneto-optical dispersion. Measurements of the refractive index of the glasses at 632.8 nm are also reported. Data on the magneto-optical properties of two high Verdet constant, heavy-metal oxide diamagnetic glasses are also included for comparison. © 1999 Society of Photo-optical Instrumentation Engineers.382214219Schweizer, T., Hewark, D.W., Payne, D.N., Jensen, T., Huber, G., Rare-earth doped chalcogenide glass laser (1996) Electron. Lett., 32 (7), pp. 666-667Hewark, D.W., Samson, B.N., Medeiros Neto, J.A., Laming, R.I., Payne, D.N., Emission at 1.3 μm from dysprosium-doped GaLaS glass (1994) Electron. Lett., 30 (12), pp. 968-970Kumta, P.N., Risbud, S.H., Rare-earth chalcogenides - An emerging class of optical materials (1994) J. Mater. Sci., 29 (5), pp. 1135-1157De Araujo, M.T., Vermelho, M.V.D., Gouveia Neto, A.S., Sombra, A.S., Medeiros Neto, J.A., Efficient second harmonic generation in praseodymium doped Ga:La:S glass for 1.3 μm optical fiber amplifiers (1996) IEEE Photonics Technol. Lett., 8 (6), pp. 821-823Schulz, P.A., Wavelength independent Faraday isolator (1989) Appl. 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Lett., 18 (10), pp. 835-837Pistoni, N.C., Martinelli, M., Vibration-insensitive fiber-optic current sensor (1993) Opt. Lett., 18 (4), pp. 314-316Wilson, D.K., Optical isolators adapt to communication needs (1991) Laser Focus World, 27 (4), pp. 175-180Balbin Villaverde, A., Munin, E., Pedroso, C.B., Linear displacement sensor based on the magneto-optical Faraday effect (1998) Sens. Actuators A, 70, pp. 211-218Munin, E., Balbin Villaverde, A., Magneto-optical rotatory dispersion of some non-linear crystals (1991) J. Phys.: Condens. Matter, 3 (27), pp. 5099-5106Munin, E., Roversi, J.A., Balbin Villaverde, A., Faraday effect and energy gap in optical materials (1992) J. Phys. D, 25 (11), pp. 1635-1639Boswarva, I.M., Howard, R.E., Lidiard, A.B., Faraday effect in semiconductors (1962) Proc. R. Soc. London, Ser. A, 269, pp. 125-141Balkanski, M., Amzaliag, E., Langer, D., Interband Faraday rotation of II-IV compounds (1966) J. Phys. Chem. Solids, 27, pp. 299-308Ramaseshan, S., Determination of the magneto-optic anomaly of some glasses (1946) Proc.-Indian Acad. Sci., Sect. A, 24, pp. 426-432Cole, H., Magneto-optic effects in glass I. Some preliminary observations on the application of magneto-optic properties to structural considerations (1950) J. Soc. Glass Technol., 34, pp. 220-237Sivaramakrishnan, V., Dispersion of Faraday rotation in some optical glasses (1957) J. Ind. Inst. Sci., A39, pp. 19-26Borrelli, N.F., Faraday rotation in glasses (1964) J. Chem. Phys., 41 (11), pp. 3289-3293Balbin Villaverde, A., Vasconcellos, E.C.C., Magnetooptical dispersion of HOYA glasses: AOT-5, AOT-44B and FR-5 (1982) Appl. Opt., 21 (8), pp. 1347-1348Borrelli, N.F., Dumbaugh, W.H., Electro- and magneto-optic effects in heavy metal oxide glasses (1987) Infrared Optical Materials and Fibers, Proc. 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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
Cadmium mixed halide glass for optical amplification at 1.3µm
No full textOptical and spectroscopic data and calculations in support of an efficient 1.3 µm amplifier in Pr3+-doped cadmium mixed halide glass host are presented. We find that the dominant parameter affecting the amplifier gain is the lifetime (325 µm) of the Pr3+-1G4 state. The long lifetime is the direct consequence of a decreased multiphonon decay rate in this low-phonon-energy glass host. We predict gain in excess of 30 dB for 100 mW pumping in low loss fibres, and for background loss of 1 dB/m, gain figures are as high as 15-20 dB
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