Optical spectroscopy of TeO2–GeO2 glasses activated with Er3+ and Tm3+ ions

The optical and spectroscopic properties of Er3+- and Tm3+-activated germano-tellurite glasses of molar composition 90TeO2: 10GeO2 and 80GeO2: 20TeO2, prepared by melt-quenching, have been studied. The refractive indices at three different wavelengths in the visible and near infrared have been measured. The vibrational properties of the glasses were studied by Raman spectroscopy. The Raman spectra indicate that the GeO2 and TeO2 components of the glasses do not well mix at the microscopic level. The spectroscopic properties of the rare earth ions were investigated by absorption spectroscopy and time resolved photoluminescence. The analysis was focused on the 4I13/2?4I15/2 transition of Er3+ ion and the 3F4?3H4 transition of Tm3+ ion, of high interest for telecommunication systems.