Er3+/Yb3+共掺锗碲酸盐玻璃的光谱性质及Judd-Ofelt理论分析

用高温熔融法制备了一种Er³⁺/Yb³⁺共掺的70TeO₂-5Li₂O-10B₂O₃-15GeO₂玻璃,测试和分析了其热稳定性、吸收光谱、荧光光谱以及红外吸收谱。应用Judd-Ofelt理论计算了玻璃中Er³⁺的强度参数、自发辐射跃迁几率、辐射寿命以及荧光分支比,同时比较了OH^-的存在对玻璃发光特性的影响。结果表明:这种玻璃具有较好的热稳定性,较宽的荧光半峰全宽和较大的受激发射截面,是一种较为合适的宽带光纤放大器的基质材料,OH^-的存在使得Er³⁺离子的荧光强度降低,荧光寿命减小。

Spectroscopic Properties and Judd-Ofelt Theory Analysis of a New Er3+/Yb3+-codoped Germanotellurite Glass

Er³⁺-doped and Er³⁺/Yb³⁺-codoped materials have played an important role in the development of broadband erbium-doped fiber amplifiers (EDFA) at the third communication window for their potential laser applications. Therefore, the choice of host material is very important in the development of more efficient op-tical amplifiers based on Er³⁺-doped glasses.The new Er³⁺ /Yb³⁺-codoped 70TeO₂-5Li₂O-10B₂O₃-15GeO₂ glass was prepared by the technique of high-temperature melting. The thermal stability, absorption spectra, fluorescence spectra and FT-IR spectra were measured and investigated. The effect of OH^- on the spectro-scopic properties of glass sample was discussed. The Judd-Ofelt theory analysis on the absorption spectra was performed and compared with other glass hosts. The oscillator strength, spontaneous emission probability, radiative lifetime and emission branching ratio of several Er³⁺ transitions were calculated according to the obtained Judd-Ofelt parameters. It was found that this studied glass has good thermal stability and it is a perfect candidate material for fiber drawing. The Judd-Ofelt parameters deriving from the absorption spectra were acquired as follows: Ω₂=5.65×10^-20 cm², Ω₄=1.21×10^-20 cm², Ω₆=0.95×10^-20 cm². The broad FWHM(77 nm) was obtained from the fluorescence spectra and the large stimulated emission cross-section σ_e^peak (8.7×10^-21 cm²) was calculated by the McCumber theory. The product of FWHM× σ_e^peak is larger than those of other glass hosts, which indicating that this studied glass may be a potentially useful candidate material host for broadband optical amplifier. In addition, the fluorescent intensity and lifetime of the ⁴I_13/2 level of Er³⁺ ions will decrease with the existence of OH^-content. The lifetime of the ⁴I_13/2 level of Er³⁺ ions increase from 1.7 ms to 2.31 ms after removing water during the melting process.