Thermal Stability and Spectroscopic Properties of Erbium-doped Tellurite Glass

Er3+-doped tellurite glasses with various Na2O/K2O ratios were prepared by conventional glass melting. Glass transition temperature Tg and crystallization temperature Tx were tested by DSC. The effect of mixed alkali on thermal stability of tellurite glasses was described. The results show that the mixed alkali is beneficial to tellurite glasses on thermal stability and the best mixed alkali molar ratio is Na2O/K2O=1/4. According to absorption spectra, JuddOfelt intensity parameters were determined and used to calculate the radiation rates, fluorescent branch ratio and radiative lifetimes of Er3+ in tellurite glasses. The J-O parameters were obtained,Ω2=4.79×10-20cm2,Ω= 1.52×10-20cm2,Ω6=0.70×10-20cm2. The stimulated emission cross sections (σe=10.40×10-21cm2) of the Er3+ ion 4I13/2→4I15/2 transition was calculated by the McCumber theory. The FWHM(FWHM=65.5nm) of the 4I13/2→4I15/2 emission and lifetimes of every level of Er3+ ion were measured and the lifetime of 4I13/2 level is 3.99ms. The spectroscopic properties of Er3+ ion were compared in different glasses. The conclusions indicate that tellurite glass is much more beneficial for optical fiber amplifier to realize broadband and high gain amplification.