Improvement of 1.53 μm emission and energy transfer of Yb3+/Er3+ co-doped tellurite glass and fiber

• Yb3+/Er3+ co-doped tellurite glass was prepared by melt-quenching method.
• Yb3+/Er3+ co-doping improved the 1.53 μm band fluorescence intensity evidently.
• Yb3+/Er3+ co-doping improved the 1.53 μm band signal gain.
• The quantitative study of energy transfer (ET) between Yb3+ and Er3+ was presented.
• The structure behavior and thermal stability of the prepared glass were studied.

To improve the 1.53 μm band emission of Er3+, the trivalent Yb3+ ions were introduced into the Er3+ single-doped tellurite glass with composition of TeO2–ZnO–La2O3, a potential gain medium for Er3+-doped fiber amplifier (EDFA). The improved effects were investigated from the measured 1.53 μm band and visible band spontaneous emission spectra together with the calculated 1.53 μm band stimulated emission (signal gain) spectra under the excitation of 975 nm laser diode (LD). It was found that Yb3+/Er3+ co-doping scheme can remarkably improve the visible band up-conversion and the 1.53 μm band fluorescence emission intensity, and meanwhile improves the 1.53 μm band signal gain to some extent, which were attributed to the result of the effective energy transfer of Yb3+:2F5/2 + Er3+:4I15/2 → Yb3+:2F7/2 + Er3+:4I11/2. The quantitative study of energy transfer mechanism was performed and microscopic energy transfer parameters between the doped rare-earth ions were determined. In addition, the spectroscopic properties of Er3+ were also investigated from the measured absorption spectrum according to the Judd–Ofelt theory, and the structure behavior and thermal stability of the prepared tellurite glass were analyzed based on the X-ray diffraction (XRD) and differential scanning calorimeter (DSC) measurements, respectively.