Energy transfer from Tm3+:3F4 to Dy3+:6H11/2 in oxyfluoride tellurite glasses

Thermal analysis and optical properties indicate that Tm3+ and Dy3+ co-doped oxyfluoride tellurite glasses can be excellent candidates for fiber amplifiers at 1.47 μm region. Substitution of GeO2 and In2O3 in tellurite glasses increased the glass stability without decreasing the lifetime of the upper Tm3+:3H4 level, and the fluoride substitution increased lifetime of excited energy levels of Tm3+ ion. Dy3+ co-doping in the Tm3+-doped oxyfluo⋮appride tellurite glasses enhanced the depopulation of the Tm3+:3F4 level through an energy transfer Tm3+:3F4→Dy3+:6H11/2. We report the measurements of crystallization, glass transition temperatures, and optical properties of Tm3+, Dy3+ co-doped oxyfluoride tellurite glasses.