Electronic and optical properties of Yb/Al/P co-doped silica optical fiber

Abstract The corresponding relationship between energy levels and absorption spectra of Yb3+ ion in Yb/Al/P co-doped silica fiber is obtained by first-principle methods. Based on the calculation result that the ortho-position (OP) substitution model has the lowest average formation energy, Yb-OP substitution model with six coordination of Yb3+ is constructed, which is a possible local microstructure in Yb/Al/P co-doped silica fiber. Due to the spin-orbital coupling effect, two occupied impurity levels are introduced into the band gap located at 2.72 eV and 4.06 eV, representing 2F5/2 and 2F7/2 manifolds respectively. The absorption peaks of 971 nm, 922 nm and 881 nm are fitted by Gaussian decomposition, corresponding to the transition 2F7/2-1 - 2F5/2-5, 2F7/2-1 - 2F5/2-6 and 2F7/2-1 -2F5/2-7. We construct the local environment model of Yb3+ ion and provide the relationship between energy levels and optical absorption of Yb3+ ion from the perspective of theoretical calculation, which is helpful to understand the Yb/Al/P co-doped silica fiber theoretically.