Validity of the McCumber Theory at High Temperatures in Erbium and Ytterbium-Doped Aluminosilicate Fibers

The temperature dependence of the emission and absorption cross sections of Er and Yb ions in rare-earth-doped aluminosilicate optical fibers is experimentally investigated. The obtained results demonstrate that the McCumber theory accurately predicts the temperature-induced changes of the emission cross section spectrum up to 500 °C when the absorption spectra measured at the considered temperature is used for the calculations instead of the one acquired at ambient temperature. Finally, we also demonstrate that the various heating steps up to 500 °C are not affecting the fiber guiding properties and no permanent effect is observed on the emission and absorption cross section spectra measured at room temperature.