Broadband and flat near-infrared emission from Er3+/Tm3+ codoped tellurite glass for amplifier applications

E r 3 + / T m 3 + codoped tellurite glasses have been synthesized using the melt-quenching technique; they are characterized by measurements of absorption spectrum, luminescence spectrum, fluorescence decay, Raman spectrum, and differential scanning calorimeter curve. Under the excitation of an 808 nm laser diode (LD), an extremely flat and broadband near-infrared emission with the full width at half-maximum of ∼ 160 n m has been obtained in tellurite glass doped with optimized E r 3 + − T m 3 + concentrations. This broadband and flat fluorescence emission is located in the region of 1350–1650 nm and covered the E, S, C, and L bands, which originate from the spectral overlapping of 1.53 µm band emission of E r 3 + : 4 I 13 / 2 → 4 I 15 / 2 transition and 1.47 µm band emission of T m 3 + : 3 H 4 → 3 F 4 transition. The Judd-Ofelt theory was applied to the absorption spectrum, and the radiative properties such as transition probability, branching ratio, and radiative lifetime of E r 3 + and T m 3 + ions have been determined to evaluate the potential luminescence characteristics. The time-resolved fluorescence decay of E r 3 + and T m 3 + ions demonstrated the existence of energy transfers between them, and the energy transfer micromechanism was further investigated quantitatively. The results indicate that tellurite glass codoped with appropriate amounts of E r 3 + − T m 3 + ions is promising for applications in broadband optical fibers and photonic devices.