Efficient 1.53μ m erbium light emission in heavily Er-doped titania-modified aluminium tellurite glasses.

Ti-Al co-doped erbium tellurite glasses have been obtained by melting mixed Er2O3, TiO2 and TeO2 batches in Al2O3 crucibles. By crucible dissoln. Al2O3 amts. from 11.5 to 18.6 mol% were introduced in the synthesized glasses. DTA of glasses points to a strong dependence of glass transition temp. Tg with the substitution extent of TeO2 by the doping oxides. No crystn. features are obsd. up to 450 C. The spectral features and decay kinetics of the IR photoluminescence of erbium demonstrate the possibility to achieve more than 50% of quantum yield of light-emission at Er3+ concns. as large as 1021 cm-3, with about 2 ms of lifetime, 8  10-21 cm2 of stimulated emission cross section, and no satn. at pump power densities higher than 10 kW cm-2. The study of the kinetics of Er-Er energy transfer suggests to ascribe these features to a particularly homogeneous dispersion of Er3+ ions in the modified tellurite network. Raman scattering measurements of the spectral distribution of vibrational modes evidence that the introduction of doping oxides leads to an increase of structural disorder without crystn. effects.