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The tellurite-tungstate glasses containing small amounts of rare-earth ions have been studied experimentally at 77 and 293 K using spectroscopic methods. The photoluminescence (PL) studies reveal the emission of efficient green-yellow light from Tb3+ ions and red light from Eu3+ ions. The Judd-Ofelt intensity parameters have been derived for Nd3+ and Er3+ ions from the absorption spectra and they have used to calculate the radiative lifetimes and branching ratios. The quantum efficiency η = 0.95 of the 4F3/2 level of Nd3+ ion is higher than the typical value of other tellurite-based glasses. For Er3+ ions, PL originating from the 4S3/2,4I11/2 and 4I13/2 levels has been observed and the luminescence decay of the first two levels has been found to be governed by radiative transitions and multiphonon relaxation involving the highest energy of Te-O vibrations.

The goal of this work was to investigate the influence of ZnO on physico-chemical properties of tellurite glasses of the TeO 2 -ZnO-PbO-La 2 O 3 system, including those doped with Yb 3+ . The effect of glass crystallization on the thermal stability and crystallizing phases formed upon the heat treatment were investigated by DTA/DSC/, XRD and microscopic methods. The spectral dependence of ellipsometric angles of the tellurite glass samples, have been studied. The influence of ZnO and Yb 3+ ion, onto changes of refractive index of tellurite glass (without RE admixture) were examined. The optical measurements were conducted on Woollam M2000 spectroscopic ellipsometer, in spectral range of 190-1700 nm. Based on obtained results it can be concluded, that admixtures of ZnO have the most considerable influence on thermal stability tellurite glasses raise.

Technology of tellurite glasses from the TeO 2 -WO 3 -PbO-La 2 O 3 has been investigated. The effect of lanthanum oxide content on tendency to the crystallization of glassy matrix has been studied. Differential thermal analysis DTA/DSC, XRD measurement have been considered in term of lanthanum oxide influence. The refractive indices (n) for series of glass compositions with various La 2 O 3 contents compared with glass without La 2 O 3 addition has been measured. From obtain results it has been stated that the refractive index sl ightly increases with the addition of the lanthanum oxides in all glass of compositions. Double crucible drawing technique was applied to drown tellurite optical fibre with high numerical aperture (0.8). Keywords: tellurite glasses, IR glasses, tellurite optic al fibre, lanthanum oxide. 1.INTRODUCTION The progress in photonics created a range of important modern applications for amorphous materials especially for glasses. Those materials are widely used in telecommunica tions, optical technology computing technology, as a optical fibre transmission medium. Recently the tellurite glasses have gained a wide attention because of their potential as hosts of rare earth elements for the development of fiber and integrated optic amplifiers and lasers covering all the main telecommunication bands. The tellurite glasses have lower p honon energies compared with the well known silicate and phosphate glasses. The low phonon energies of tellurite glasses are responsible for their improved (IR) transmission (up to 6 µm) and low multi-phonon relaxation rates for rare-earth excited states. Therefore, tellurite glasses are potential candidates for IR transmitting devices and also host for IR emitting rare-earths [1]. Tellurite glasses have low Tg and high thermal stability against crystallization, which is the primary factor for successful fiber drawing with improved properties [2]. Furthermore, they exhibit high refractive index, a wide transmission range (0.35–5µ m), low process temperature and significant non-linear properties [3]. Glass integrated optics can offer excellent flexibility to accommodate more functions and it is suitable to cost effective mass production. TeO

Technology of tellurite glasses from the TeO2-WO3-PbO system rare earth doped has been investigated. This kind of materials possess high transparency in the visible and IR spectral range (up to 6μm) and low dispersion. Because of introduction of rare earth into glass structure, obtained materials possess very good properties such as: luminescence, high refractive index (higher than 2.0), which is a consequence of high polarizability of tellurium ions. Addition of lanthanum fluoride into glass structure from the TeO2-WO3-PbO system change the tendency to crystallization. The effects of the crystallization of glasses from the TeO2-WO3-PbO system LaF3 and other rare earths doped were a subject of the study. Differential thermal analysis, XRD, SEM measurements have been considered in term of rare earth influence. Particular interest present rare earth doped materials. This is caused by their relatively large radius compared to the other compounds as well due to specific luminescent properties of the rare earth ions. In the present work the data concerning the influence of the rare earth on the emission properties of glasses has been presented.© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.