Spectral properties and thermal stability of Er~(3+)/Yb~(3+) codoped tungsten-tellurite glasses

摘要

The spectral properties of Er~(3+)/Yb~(3+) codoped tungsten-tellurite glasses are investigated based on the Judd-Ofelt and McCumber theories. The compositional dependence of intensity parameter Ω_2 is attributed to the covalency of Er-O bonds for TeO_2-WO_3-La_2O_3 and TeO_2-WO_3-Bi_2O_3 glasses while for TeO_2-WO_3-BaO glasses, Ω_2 is mainly determined by the asymmetry in the local structures around Er~(3+) ions. The fluorescence full width at half maximum (FWHM) and the peak emission cross-section (σ_(peak)) of the ~4I_(13/2) → ~4I_(15/2) transition of Er~(3+) ions in different glass hosts have been compared. The results indicate that the tungsten-tellurite glass is a promising host material for 1.55 μm broadband amplification.