Fabrication and characterization of solution doped gallium and barium preforms

Abstract

using standard MCVD with solution doping technique. The maximum concentrations of dopants that could be incorporated into silica were found to be 1.4 and 3.0 mol% for barium oxide and gallium oxide, respectively. At these concentrations, the final preforms showed reduced transparency in the core region indicating phase separation. Both of these dopants behavior in silica was discussed and compared with aluminum oxide being the typical dopant used in rare earth doped-silica fibers. The alumina-doped preform was observed to show opacity in the core region when the concentration of aluminum oxide was 10 mol%.

The uniqueness of glass for passive thermal management for optical fibers

“…37 BaO-doped silica optical fibers have been fabricated using MCVD and reported to exhibit better photodarkening performance in comparison with the conventional aluminosilicate fibers. 38,39 Doping of BaO into SiO 2 is limited by a subsolidus immiscibility, which ranges from least 2 to 28 mol% BaO with upper consolute point of 10 mol% BaO and temperature of 1460 • C. 40 For a glass to be formed, the critical cooling rate needed to exceed about 10 3 K/s, 41 which is commensurate with that for fiber drawing. When BaO has been (solution) doped into silica preforms using the MCVD process, concentrations of <2 mol% were realized due to phase separation at the processing conditions.…”

“…As a second illustration, consider the BaO–SiO 2 system, which has been studied at least as far back as 1922 37 . BaO‐doped silica optical fibers have been fabricated using MCVD and reported to exhibit better photodarkening performance in comparison with the conventional aluminosilicate fibers 38,39 . Doping of BaO into SiO 2 is limited by a subsolidus immiscibility, which ranges from least 2 to 28 mol% BaO with upper consolute point of 10 mol% BaO and temperature of 1460°C 40 .…”