Influence of B2O3 on Spectroscopic Properties of Er3+/Yb3+ Co-Doped Tungsten-Tellurite Glasses

A series of novel Er3+/Yb3+ co-doped (85 – x)TeO2-15WO3 - xB2O3(TWB; x = 2%, 5%, 8% (mole fraction)) glasses were prepared. Influence of B2O3 on the spectroscopic properties of Er3+/Yb3+ co-doped tungsten-tellurite glasses were investigated. It is found that the intensity of 1.5 μm fluorescence, lifetime of the 4I13/2 level and upconversion fluorescence all decrease with the increase of B2O3 content. The product of full width at half maximum (FWHM) and stimulated emission cross-section (σ) of Er3+ :4I13/2→4I15/2 transition has an optimum when B2O3 is 5% (mole fraction). The emission spectra of Er3+: 4I13/2→4I15/2 transition was analyzed using peak-fit routine, and an equivalent four-level system was proposed to estimate the stark splitting for the 4I15/2 and 4I13/2 levels of Er3+ ions in TWB glasses at room temperature.