Spectral properties and thermal stability of Er3+/Yb3+ codoped tungsten–tellurite glasses

The spectral properties of Er3+/Yb3+ codoped tungsten–tellurite glasses are investigated based on the Judd–Ofelt and McCumber theories. The compositional dependence of intensity parameter Ω2 is attributed to the covalency of Er–O bonds for TeO2–WO3–La2O3 and TeO2–WO3–Bi2O3 glasses while for TeO2–WO3–BaO glasses, Ω2 is mainly determined by the asymmetry in the local structures around Er3+ ions. The fluorescence full width at half maximum (FWHM) and the peak emission cross-section (σpeak) of the 4I13/2 → 4I15/2 transition of Er3+ 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.