The spectroscopic properties of Er(3+)-doped TeO(2)-Nb(2)O(5) glasses with high mechanical strength performance

(100-x)TeO(2)-xNb(2)O(5) (x=5-20) niobic tellurite glasses doped with 0.5 mol.% Er(2)O(3) were synthesized, and their thermal, mechanical, and spectroscopic properties were measured and compared to the properties of the typical 75TeO(2)-20ZnO-5Na(2)O (TZN) tellurite glass. The refractive index (n(d)), density (rho), and glass transition temperature (T(g)) of bulk glasses increase with the Nb(2)O(5) content. The Vickers microhardness (H(v)) of bulk glass in niobic tellurite glasses also increases with the Nb(2)O(5) content. The values (2.5-3.2GPa) of H(v) in the niobic tellurite glasses are 47-88% larger than that (1.7GPa) in TZN glass. The effect of Nb(2)O(5) content on absorption spectra, the Judd-Ofelt parameters Omega(t) (t=2, 4, 6), fluorescence spectra and the lifetimes of Er(3+):I(13/2) level were also investigated, and the stimulated emission cross-section was calculated from McCumber theory. With increasing Nb(2)O(5) content in the glass composition, the Omega(t) (t=2, 4, 6) parameters, fluorescence full width at half maximum (FWHM) of I(13/2) of Er(3+) increase, while the (4)I(13/2) lifetimes of Er(3+) decreases. Compared with TZN glass, the gain bandwidth properties of Er(3+)-doped TeO(2)-Nb(2)O(5) glass is much larger than in tellurite glass based TeO(2)-ZnO-Na(2)O system, bismush-based glass, germanate, and silicate glasses, which indicates that TeO(2)-Nb(2)O(5) glasses are better choice as a practical available host material for broadband Er(3+)-doped amplifier.