1,721,073 research outputs found
Measurement of photodarkening in Yb-doped aluminosilicate fibres at elevated temperature
Full text linkPhotodarkening behaviour in Yb-doped aluminosilicate fibres at elevated temperatures is reported. The fibre was core-pumped at 977 nm and the transmitted powers were monitored at 633 (probe) and 977 nm (pump) simultaneously with ~47% of population inversion of Yb3+ ions. A saturated photodarkening loss was found, which is inversely proportional to temperature and, at ~573 K, the loss was negligible at the pump wavelength. From the decay curves at different temperatures, it was found that the photodarkening involves second-order kinetics to form colour centres
In-situ solution doping technique for novel geometry rare-earth doped fiber fabrication
No full textWe report on the fabrication and characterization of a YDFL with a pedestal geometry fabricated using an in-situ solution doping process. The fiber has a unique non-stressed inner-cladding and exhibits good efficiency
Modification of spectroscopic properties of Bismuth doped silica fiber by post-fabrication process and different fabrication methods
No full textThe spectroscopic properties of pristine and H2-loaded MCVD based Bi-doped aluminosilicate fibers were investigated. Also, the properties of Bi-doped fiber, fabricated by powder-in-tube method, have been compared to MCVD based Bi fiber
Ytterbium-doped low-NA P-Al-silicate large-mode-area fiber for high power applications
No full textWe demonstrate an efficient, ytterbium-doped low-NA fiber with core glass containing high levels of Al2O3 and P2O5 in silica host that shows low-photodarkening and generated 175 W of continuous-wave output power with 80% laser efficiency
Ytterbium-doped Y<sub>2</sub>O<sub>3</sub> nanoparticle silica optical fibers for high power fiber lasers with suppressed photodarkening
No full textWe report efficient laser demonstration and spectroscopic characteristics of a Yb-doped Y2O3 (or Y3Al5O12) nanoparticle silica fiber developed by conventional fiber fabrication technique. The spectroscopy study evidences modification in the environment of Yb ions by the Y2O3 nanoparticles. As a result, photodarkening induced loss is reduced by 20 times relative to Yb-doped aluminosilicate fibers. The fiber is suitable for power scaling with good laser slope efficiency of 79%
Ytterbium doped nano-crystalline optical fiber for reduced photodarkening
No full textWe report suppression of photodarkening in Yb-doped nano-crystalline fibers in silica host. The photodarkening induced loss reduced by 20 times compared to Yb-doped aluminosilicate fibers. The laser efficiency of the nano-crystalline fiber was 79%
5.4W cladding-pumped Nd:YAG silica fiber laser
Full text linkWe report on the spectroscopy and laser characteristics of Nd-doped fiber, fabricated by rod-in-tube from Nd:YAG as a core material with silica cladding. A cladding-pumped CW laser operation at 1058nm with 52% slope-efficiency is demonstrated
Linearly polarized ytterbium-doped fiber laser in a pedestal design with aluminosilicate inner cladding
No full textYtterbium-doped polarization-maintaining fiber in a pedestal geometry is demonstrated using MCVD and a novel in-situ doping technique. The aluminosilicate pedestal layers minimize the thermal expansion mismatch against the silica outer cladding and permits complete freedom of location for the stress-applying parts in the fiber. A birefringence of 2.4×10-4 is experimentally determined. The fiber delivers linearly polarized laser exhibiting 79% slope efficiency with a polarization extinction ratio of 12 d
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
- …
