Spectroscopic properties and upconversion studies of Er3+-doped SiO2-Al2O3-Na2CO3-SrF2-CaF2 oxyfluoride glasses for optical amplifier applications

Er3+ doped SiO2-Al2O3-Na2CO3-SrF2-CaF2 oxyfluoride glasses have been prepared by melt quenching method and were investigated by optical absorption spectra. Judd-Ofelt intensity parameters were calculated and used to predict radiative properties of 1.0 mol% of Er3+ ions doped glass. The visible photoluminescence and lifetime spectra were recorded under the 379 nm excitation source. In the near infrared region the emission spectra and their decays corresponding to 4I13/2 → 4I15/2 laser transition of Er3+ ions, were recorded by excitation source of laser diode at wavelength of 980 nm. The lifetime of 4I13/2 level has been decreased (6.38-1.95 ms) with increasing of Er3+ ion concentration from 0.1 to 2.0 mol%. The upconversion studies were investigated as a function of Er3+ ions concentration in oxyfluoride glasses. The mechanism involved in the energy transfer process corresponding to an increase in the green and red emission upconversion intensities with increasing of Er3+ ions concentration were discussed. The spectroscopic characteristics of 1 mol% of Er3+doped oxyfluorosilicate glasses were compared with other host materials. The stimulated emission cross-section and gain bandwidth have been calculated and found to be 9.8 × 10−21 cm2 and 0.52 × 10-25 cm3 for the 4I13/2 → 4I15/2 (1.535 µm) transition and is most useful for optical amplifier applications.