Extruded suspended core fibers from lanthanum-aluminum-silicate glass

We report the use of the extrusion technique at highest temperatures to date (975 °C-1000 °C) for the fabrication of suspended core fibers (SCFs) from glass with molar composition 65 SiO2-20 Al2O3-15 La2O3 (SAL65). Through adjusting die design and fabrication conditions, extruded preforms for fibers with two different core sizes (1.2 µm and 3.1 µm) were successfully produced. Cross-sectional microstructure and material loss of these fibers highlight the potential of the extrusion technique for fabrication of microstructured optical fibers from glasses with high softening temperature and thus high thermal and mechanical stability. © 2020. All rights reserved

Impact of rare earth doping on the luminescence of lanthanum aluminum silicate glasses for radiation sensing

Large core soft glass fibers have been demonstrated to be promising candidates as intrinsic fiber sensors for radiation detection and dosimetry applications. Doping with rare earth ions enhanced their radiation sensitivity. SiO2-Al2O3-La2O3 (SAL) glasses offer easy fabrication of large core fibers with high rare earth concentration and higher mechanical strength than soft glasses. This paper evaluates the suitability of the SAL glass type for radiation dosimetry based on optically stimulated luminescence (OSL) via a comprehensive investigation of the spectroscopic and dosimetric properties of undoped and differently rare earth doped bulk SAL glass samples. Due to the low intensity of the rare earth luminescence peaks in the 250–400 nm OSL detection range, the OSL response for all the SAL glasses is not caused by the rare earth ions but by radiation-induced defects that act as intrinsic centers for the recombination of electrons and holes produced by the ionizing radiation, trapped in fabrication induced defect centers, and then released via stimulation with 470 nm light. The rare earth ions interfere with these processes involving intrinsic centers. This dosimetric behavior of highly rare earth doped SAL glasses suggests that enhancement of OSL response requires lower rare earth concentrations and/or longer wavelength OSL detection range

Higher borides and oxygen-enriched Mg-B-O inclusions as possible pinning centers in nanostructural magnesium diboride and the influence of additives on their formation

The study of high pressure (2 GPa) synthesized MgB2-based materials allows us to conclude that higher borides (with near MgB12 stoichiometry) and oxygen-enriched Mg-B-O inclusions can be pinning centers in nanostructural magnesium diboride matrix (with average grain sizes of 15-37 nm). It has been established that additions of Ti or SiC as well as manufacturing temperature can affect the size, amount and distribution of these inclusions in the material structure and thus, influence critical current density. The superconducting behavior of materials with near MgB12 stoichiometry of matrix is discussed.Comment: 4 pages, 1 figues, presented at VORTEX VI-2009, accepted for Physica

Structured material combined HMO-silica fibers: preparation, optical and mechanical behaviour

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Focus on glass-powder method for the fabrication of specialty optical fibres

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Process developments and applications around the powder in tube technique

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Highly germanium and lanthanum modified silica based glasses in microstructured optical fibers for nonlinear applications

International audienceModified core glass materials in silica-clad microstructured fibers (MOFs) promise efficient conversion of non-linear processes, e.g. for supercontinuum (SC) generation. We used extremely highly germanium-doped silica (max. 36 mol% GeO2) and lanthanum aluminum silicate glasses with high lanthanum oxide concentration (max. 10 mol% La2O3) as core materials. The microstructured optical fibers (Ge-MOFs, La-MOFs) were prepared in five air ring architecture by a stack-and-draw technique using silica for the cladding region. The MOFs show loss minima of about 0.05 dB m−1 (Ge-MOF) and 1.3 dB m−1 (La-MOF) at a wavelength of 1.064 μm. Such Ge-MOFs and La-MOFs are compatible with conventional silica fibers giving low loss splices with standard single mode fibers. The non-linearity of the La-MOF is approximately two times higher than that of the Ge-MOF, but shows a significantly higher spectral loss. Ge-MOF and La-MOF can both produce similar ultra-broad band supercontinuum spectra from VIS (540 nm and 500 nm) to IR range (2400 nm and 2220 nm) by being pumped with a passively Q-switched Nd:YAG microchip laser

Grating Effect in Lanthanum Aluminum Silicate Glass Fiber

International audienceWe experimentally demonstrate a Type I grating effect in a lanthanum-aluminum silicate fiber for the first time, to the best of our knowledge. This grating shows a temperature sensitivity ~8.71 pm/oC, which is lower than that of FBG in standard single-mode fiber

Study of Lanthanum Aluminum Silicate Glasses for Passive and Active Optical Fibers

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