91 research outputs found
Structural and optical properties on thulium-doped LHPG-grown Ta2O5 fibres
Structural, spectroscopic and dielectric properties of thulium-doped laser-heated pedestal Ta2O5 as-grown fibres were studied. Undoped samples grow preferentially with a single crystalline monoclinic structure. The fibre with the lowest thulium content (0.1 at%) also shows predominantly a monoclinic phase and no intra-4f12 Tm3+ recombination was observed. For sample with the highest thulium amount (1.0 at%), the appearance of a dominant triclinic phase as well as intraionic optical activation was observed. The dependence of photoluminescence on excitation energy allows identification of different site locations of Tm3+ ions in the lattice. The absence of recombination between the first and the ground-state multiplets as well as the temperature dependence of the observed transitions was justified by an efficient energy transfer between the Tm3+ ions. Microwave dielectric properties were investigated using the small perturbation theory. At a frequency of 5 GHz, the undoped material exhibits a dielectric permittivity of 21 and for thulium-doped Ta2O5 samples it decreases to 18 for the highest doping concentration. Nevertheless, the dielectric losses maintain a very low value.FCT - PTDC/CTM/66195/2006FCT - PTDC/FIS/66262/2006FCT - PTDC/FIS/72843/200
Distributed Model of Two-Level Asymmetrical PCB Interconnect Tree
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" Influence de la température sur l'intégrité des signaux haut débit véhiculés dans les interconnexions de PCB "
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Fast Estimation of High-Speed Signal Integrity for Coupled PCB Interconnects
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Experimental validation of balanced tree interconnection model for high speed signal integrity
International audienceExperimental validation of balanced tree interconnection model for high speed signal integrit
Electrical Performance Modeling of Unbalanced Comb Tree Networks on Advanced PCB Interconnects for High-Rate Clock Signal Distribution
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“Benefit on Interconnect Performance of a Relaxed Wire Density in a 45 nm Node of the Back End of Line”
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Extraction de l'impédance caractéristique d'interconnexions
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“Keep on shrinking interconnect size: is it still the best solution ?”
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DC to Radio-Frequency Characterization of ZrO2 Dielectric for "Metal-Insulator-Metal" Integrated Capacitors"
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