Yb3+-Er3+ co-doped Na2O-GeO2-PbO glass suitable for developing optical fiber lasers and amplifiers has been fabricated. The energy transfer efficiency from Yb3+ to Er3+ was investigated in the glasses with different Yb3+-Er3+ concentration ratios and the maximum energy transfer efficiency was found to be 67% at the Yb3+-Er3+ concentration ratio of 5:1. Subsequently, the studies of upconversion emissions in the visible range were performed. An intense green together with a relatively weak red emission was observed under the excitation of 976nm diode laser. The quadratic dependence of the green emission on excitation power indicates that a two-photon absorption process occurs under a 976nm excitation. However, for the red emission the slope of log-log plot of integrated intensity versus pump power declines with increasing Yb3+ ions content, indicating it is not resulted from a biphotonic process.

Blue up-conversion luminescence properties in Tm3+-doped lead chloride tellurite glasses have been studied under 980nm excitation. The intense blue and relatively weak red emissions centered at 476 and 649nm corresponding to the transitions 1G4 → 3H6 and 1G4 → 3H4 of Tm3+, respectively, are simultaneously observed at room temperature. The effect of PbCl2 on up-conversion intensity is observed and discussed, and possible up-conversion mechanisms are evaluated. The intense blue up-conversion luminescence of Tm3+-doped lead chloride tellurite glasses may be a potentially useful material for developing up-conversion optical devices.

The spectroscopic properties of Er3+-doped lead oxyfluorosilicate glasses were analyzed with Judd-Ofelt and McCumber theories. The obtained data suggest that the fluorescence full width at half maximum (FWHM) is related to the X6 parameter, the larger the X6 parameter, and the broader the FWHM. The results showed that Er3+-doped 45SiO2-5Bi2O3-50PbF2 glass had the broadest FWHM (64nm) and large stimulated emission cross-section (0.73×10-20cm2) in these glass samples. Compared with other glass hosts, the gain bandwidth properties of Er3+-doped 45SiO2-5Bi2O3-50PbF2 glass is close to those of tellurite and bismuth glasses, and has advantage over those of silicate, phosphate and germante glasses. The results suggest that Er3+-doped 45SiO2-5Bi2O3-50PbF2 glass can be used as potential host material for developing broadband optical amplifiers in wavelength-division-multiplexingnetwork 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.