Er3+/Yb3+共掺碲钨酸盐玻璃的热稳定性和1.5μm波段的光谱性质

制备了Er³⁺/Yb³⁺共掺的碲钨酸盐玻璃样品,TeO₂-WO₃-R_mO_n(R_mO_n=PbO,BaO,La₂O₃,Bi₂O₃),研究了样品的热稳定性和1.5μm波段的光谱性质。碲酸盐中引入WO₃的目的是为提高基质的声子能量,使Er³⁺离子⁴I_13/2→⁴I_15/2的多声子弛豫速率增加,从而提高⁴I_13/2能级上的Er³⁺离子数,这对提高1.5μm处的荧光强度有利,另外加入WO₃也能提高碲酸盐玻璃的抗析晶能力。测试了样品的FT-IR光谱,发现碲钨酸盐玻璃样品中存在着TeO₄、TeO₃、WO₄和WO₆结构体。周围环境的不对称性导致Er³⁺在1.5μm处的光谱有非均匀的展宽和大的受激发射截面。Er³⁺在70TeO₂-20WO₃-10Bi₂O₃玻璃中⁴I_13/2→⁴I_15/2能级发射的荧光半峰全宽(FWHM)为77nm,应用McCumber理论计算的受激发射截面(σ^peak)为1.03×10^-20cm²。其FWHM×σ_peak乘积远大于掺Er³⁺的铋酸盐、磷酸盐、碲酸盐和硅酸盐玻璃,说明碲钨酸盐玻璃是一种制备宽带光纤放大器优良基质材料。

Er3+/Yb3+ Codoped Tungsten-tellurite Glasses: the Thermal Stability and Spectral Properties at 1.5 μm Band

Er3+/Yb3+ codoped tungsten-tellurite (WT) glasses, TeO2-WO3-RmOn (RmOn =PbO, BaO, La2O3, Bi2O3), were prepared and investigated. WO3 has been introduced in the tellurite glasses due to the following two reasons: The first one is to increase the phonon energy and the multi-phonon relaxation rate of the Er3+:4I11/2→4I13/2 transition, which benefits the population inversion between the 4I13/2 and 4I15/2 level of Er3+. The second is to enhance the thermal stability against crystallization. The structural studies were done through FT-IR spectral analysis and revealed that these glasses contain TeO4, TeO3, WO4 and WO6 units as the local structures. The asymmetry of Er3+ sites results in inhomogeneous broadening of spectra and large emission cross-section at 1.5 μm band. The fluorescence full width at half maximum FWHM=77 nm, and the peak of the emission cross-section σpeak =1.03×10-20 cm2, are manifested in 70TeO2-20WO3-10Bi2O3 glass. The gain bandwidth properties, FWHM×σepeak, of Er3+ in WT glasses have advantages over those of bismuthate, phosphate, tellurite and silicate glasses, indicating the WT glasses are promising host materials for 1.5 μm broadband amplification.