Effects of F− on the optical and spectroscopic properties of Yb3+/Al3+-co-doped silica glass

Yb3+/Al3+-co-doped silica glasses with different F− content were prepared in this work by sol–gel method combined with high temperature sintering. XRF, FTIR and XPS methods were used to confirm the presence of F−. The effects of F− on the optical and spectroscopic properties of these glasses have been investigated. It is worth to notice that the F−/Si4+ mass ratio equal to 9% is a significant value showing a real change in the variation trends of numerous following parameters: refractive index, UV absorption edge, absorption and emission cross sections, scalar crystal-field NJ and fluorescent lifetimes. Furthermore, introduction of F− can adjust the refractive index of Yb3+/Al3+-co-doped silica glass and it is useful for large mode area (LMA) fibers.