[Influence of erbium ion concentration on Judd-Ofelt parameters of Er3+ -doped tellurite glass].

Er3+ -doped tellurite glasses with four different concentrations were fabricated, and the oscillator strength of Er3+ in the tellurite glasses were calculated through the absorption spectra of the glasses. The Judd-Ofelt intensity parameter omega i, spontaneous transition probability A, fluorescence branching ratio beta, and radiative lifetime tau rad of Er3+ were calculated on the basis of Judd-Ofelt theory, and the effect of the erbium ion concentration on the above optical parameters was also discussed. The fluorescence spectra of Er3+: (4)I(13/2)--> (4)I(15/2) transition and the lifetime of Er3+: (4)I(13/2) level of the samples were measured. The stimulated emission cross-section of (4)I(13/2)--> (4)I(15/2) transition of the samples was finally calculated by using McCumber theory. The results show that with the increase in the Er3+ concentration, the oscillator strength and spontaneous transition probability A of Er3+ increase, while the fluorescence branching ratio beta of Er3+ shows little difference. The stimulated emission cross-section of Er3+: (4)I(13/2)--> (4)I(15/2) transition of the samples changes slightly with the increase in the Er3+ concentration. All the fluorescence effective line widths for the four different Er3+ concentration samples are nearly 50 nm.