Enhanced gain bandwidth of Tm³⁺ and Er³⁺ doped tellurite glasses for broadband optical amplifier

In this work, (90-x-y)TeO₂-10GeO₂-(x)Tm₂O₃-(y)Er₂O₃ composition of germano-tellurite glasses were synthesized by traditional melting and quenching technique and the spectroscopic properties of synthesized glasses were investigated. The values of Judd-Ofelt (JO) intensity parameters (Ω_t(t = 2, 4, 6)), spontaneous transition probabilities (Α), branching ratios (β) and radiative lifetimes (τ_R) were obtained by using the Judd-Ofelt (JO) theory and absorption spectra. The stimulated emission cross-sections of TG:Tm and TG:Er glasses in 1.47 μm and 1.53 μm wavelength regions were calculated by Füchtbauer-Ladenburg formula and McCumber theory, respectively. The gain bandwidth-cross section product of TGTm0.5 and TGEr1 glasses was found to be 445.76 × 10⁻²⁸ cm³ and 849 × 10⁻²⁸ cm³, respectively. The fluorescence lifetime measurements were done for the ³F₄ and ⁴I_13/2 levels to compare with the radiative lifetimes. These results suggest that the TG:Tm and TG:Er studied glasses can potentially possess wider gain bandwidth for S-band amplifier and broadband optical amplifier WDM at 1.53 μm, respectively.