Lifetime of the⁴I_13/2 excited level of the Er ³⁺-ion in the glass system TeO₂-WO₃-Na ₂O-Nb₂O₅

Tellurite glasses optical fibers became promising for optical amplifiers due to its high rare earth ions solubility. One of the most important parameter for optical amplification is the lifetime of the excited states, which strongly depends on the crystal field around the ions. That crystal field changes dramatically with the host glass and with rare earth concentration. Excited state lifetime studies have been performed on Er³⁺-doped-TeO ₂-WO₃-Na₂O-Nb₂O₅ glass system. Therefore, we decided to study the Ei³⁺ excited states lifetimes and compared with the Judd-Ofelt theory predictions. We measured only the ⁴I_13/2 to ⁴I_15/2 transitions lifetimes. The other transitions lifetimes can be inferred by knowing the Ω₂, Ω₄, Ω₆ Judd-Ofelt parameters. These parameters were calculated with the electric-magnetic dipole transition oscillator strength for the desired excited levels and ground state obtained from the optical absorption spectra. After performing this calculation we estimated that maximum quantum efficiency (η), measured/calculated lifetimes ratio, would be achieved at 7500ppm (%wt) Er³⁺ content.