Upconversion fluorescence properties of a new Er3þ/Yb3þ-codoped lead oxyfluorosilicate glass under 975 nm excitation areinvestigated. The blue, intense green and red emissions centered at 408, 529, 545, and 667nm, corresponding to the 2H9/2→4I15/2, 2H11/2→4I15/2, 4S3/2→4I15/2, and 4F9/2→4I15/2 transitions of Er3+, respectively, were simultaneously observed at room temperature. The important role of Yb2O3 in upconversion intensity is observed, and the influence of Yb2O3 and PbF2 on blue, green and red emissions is compared and discussed. The dependence of upconversion intensities on excitation power and possible upconversion mechanisms are evaluated.

Er3+-doped heavy metal oxyfluoride germanate glass suitable for developing potential optical amplifiers and upconversion lasers has been fabricated and characterized. Under 975nm excitation, intense and broad 1533nm infrared fluorescence and visible upconversion fluorescence were observed. For 1533nm emission band, the full width at half maximum (FWHM) is 57nm, the fluorescence lifetime is 5.7ms, and the quantum efficiency is-100%. Efficient 529, 551, and 657nm upconversion emissions correspond to the transitions 2H11/2 → 4I15/2, 4S3/2 → 4I15/2, and 4F9/2 → 4I15/2, respectively. Raman spectrum indicates the important role of fluoride ions in the formation of glass network. The dependence of upconversion intensities on excitation power involves two-photon absorption processes for the three emission bands. The possible upconversion mechanisms are discussed based on the energy matching conditions and the quadratic dependence on excitation power.

Er3+-doped 50SiO2-(502x) PbO-xPbF glasses were prepared. The effect of PbF content on refractive indices, densities, absorptionspectra, the Judd-Ofelt parameters Ωt (t52,4,6), fluorescence spectra and the lifetimes of I level of Er in 50SiO2-(502x) PbO-t13-2xPbF glasses were investigated, and the stimulated emission cross-section was calculated from McCumber theory. With increasing PbF2 content in the glass composition, the V parameter, fluorescence full width at half maximum (FWHM) and lifetimes of I level of Ω6 Er increase, while refractive indices and densities decrease. Compared with other glass hosts, the gain bandwidth properties of 31 Er-doped 50SiO2-50PbF glass is close to those of tellurite and bismuth glasses, and has an advantage over those of silicate, phosphateand germante glasses. The broad and flat → emission of Er around 1.55mm can be used as host material for potential broadband optical amplifier in the wavelength-division-multiplexing (WDM) network system.

In order to elucidate the short-rang order structure in the ternary system Na2O-(3-x) SiO2-xGeO2 we employ in this study a quantitative description to determine the molar ratios of Na2O to SiO2 (RSi) and Na2O to GeO2 (RGe) in sodium germanosilicates. The calculated results show that the sodium oxide has no preference for the silicate or the germanate part of the network and there are the same short-rang order units in various Na2O-(3-x) SiO2-xGeO2 glasses. The Raman spectra also confirm the calculated results.