Composition Dependence of Spectroscopic Properties of Er³⁺ Doped TeO₂-WO₃-ZnO Glasses

Er³⁺-doped TeO₂-WO₃-ZnO glasses were prepared and the absorption spectra, emission spectra and fluorescence lifetimes were measured. With more TeO₂ content in the glasses, the emission full width at half maximum (FWHM) increases while the lifetime of the ⁴I_13/2level of Er³⁺ decreases. The stimulated emission cross-section of Er³⁺ calculated by the McCumber theory is as large as 0.86 pm². The product of the FWHM and the emission cross-section σ_e of Er³⁺ in TeO₂-WO₃-ZnO glass is larger than those in other glasses, which indicates that the glasses are promising candidates for Er³⁺-doped broadband amplifiers. The Judd-Offelt parameter Ω₆ shows close composition dependence of the 1.5 μm emission bandwidth. The more the TeO₂ content is, the larger the values of Ω₆ and FWHM.