First-principles study of local structure and optical properties of Yb/F co-doped silica glass for optical fiber applications

Abstract

We calculate the geometric and optical properties of Yb/F co-doped silica glass which is the main component of optical fiber, by using first-principles. In the non-coplanar open-loop model (NCOL), by using the Bader charge method, our results revealed that the valence electrons of Yb ion are 1.89, which is extremely close to the Yb2+ ion. The absorption peaks, respectively, located at 3.2 eV (390 nm) and 4 eV (330 nm), which are close to typical Yb2+ characteristic absorption obtained from the experimental test. The absorption peaks correspond to the transitions from 1S0–2F7/2 T2g-1 and 1S0 to 2F5/2 T2g-3. Incorporation of F element and the formation of open-loop ring structure may make the Yb3+ ion more likely transform to Yb2+ ion. The NCOL model provides theoretical guidance for the experimental preparation of Yb-doped silica fiber.