Effects of Nb2O5 on thermal stability and optical properties of Er3+-doped tellurite glasses

Er3+-doped tellurite glasses with molar compositions of xNb(2)O(5)-(14.7-x)Na2O-10ZnO-5K(2)O-10GeO(2)-60TeO(2)-0.3Er(2)O(3) (x = 0, 3, 5, 7 and 9) have been investigated for developing 1.5 mu m fibre and planar amplifiers. The effects of Nb2O5 on the thermal stability and optical properties of Er3+-doped tellurite glasses have been discussed. It is noted that the incorporation of Nb2O5 (x = 5) increases the thermal stability of tellurite glasses significantly. Er3+-doped niobium tellurite glasses exhibit a large stimulated emission cross-section (7.2 x 10(-21)-10.7 x 10(-21) cm(2)) and the gain bandwidth, FWHM x sigma(peak)(e) (274 x 10(-28)-480 x 10(-28) cm(3)), which are significantly higher than that of silicate and phosphate glasses. In addition, the intensity of upconversion luminescence of the Er3+-doped niobium tellurite glasses decreases rapidly with increasing Nb2O5 content. As a result, Er3+-doped niobium tellurite glasses might be a potential candidate for developing laser or optical amplifier devices.