Research On The Preparation And Properties Of Tellurite Glass

Er3+doped fiber amplifier (EDFA) because of its-excellent optical properties, is used Widely in transmission system of light Er3+~doped tellurite glass possesses large emission cross-section, flattened broad bandwidth, relative lower phonon energy and a larger; refractive index than that of other oxide glasses, and so, on. Due to their excellent properties, the Er3+-doped tellurite glasses are used as candidates for broad band Er3+-doped fiber amplifiers, and have been received much attention. However, the difficulty for tellurite glasses is their relatively low thermal stability and high thermal expansion. These disadvantages result in glass fibers made from these glasses are too fragile and do not show light guiding at all. in order to improve the thermal stability of tellurite glass, it is necessary to improve qhemical composition of the glass and fabrication techniques.Er3+-doped tellurite glasses were elaborated in persent work. B2O3, GeO2, SiO2and Al2O3has been introduced into the compositions of TeO2-ZnO-Na2O, respectively. Appearance of the glasses with compositions content B2O3and GeO2were better than the compositions with Al2O3.And the glass compositions with SiO2could not form glass phase.Tellurite glass were elaborated from melt-quenching method with powders been immersed in CCl4which as a reagent of dehydration. The structure has been investigated by means of Fourier transform infrared spedroscopy (FT-IR) spectra. The phenomenon reveals that OH contentsin the glass matrix had been reduced effectively. And differential scanning calorimetry (DSC) and thermal inechanical analysis (DTA) determined thermal parameters. It is found that glasses obtained from present work have high thermal stability against crystallization,. The difference of crystallization temperature (Tx) and glass transition temperature (Tg) is lager.than,155℃and thermal expansion (a) is in the range of8.668~12.279×l0-6/℃. It suggests that introducing B2O3and GeO2into tellurite glasses can improve their thermal stability. Theory of Judd-Ofelt and McCumber are applied to analysis optical spectra. Intensity parametersΩλ (λ=2t4,6), transition probabilities Ade, radiative lifetimes Ï„i,and branching ratios β of the Er3+transitions were obtained. And eission cross-sections σemis of Er3+:4132â†'4I152transitions have been calculated The values of Ω/Ω6is in the range from0.74to0.872, σemis x Full width at half maximum (FWHM) varies from400×1-21to500×10-21cm2·nm, and σemis×τi, is in the range of55~108×10-21cm2·ms. All parameters above indicate that the properties of Er3+-doped TeO2-ZnO-Na2O-B2O3-GeO2(TZNBG) glasses have been improved effectively in present work. And the glasls can be used as ideal material for optical amplifiers.Further more, Er3+and Dy3+co-doped tellurite glasses were prepared. Absorption spectrum and emission spectra were analysed according to the theory of Judd-Ofelt and McCumber. Based on the results been abtained, the optical property of Er3+in the50TeO2-20ZnO-5Na2O-20B2Or5GeO2-l wt%Er2O3glass were improved most when content of Dy3+is0.5wt%. And the optical property of Er3+decreased when the content of Dy3+increased.