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Atomic Structures and Electronic States of Divalent Bismuth in Bi-Doped Silica Optical Fiber

We report first-principles calculations of cluster SiO2 (24-atom) with and without divalent bismuth (Bi2+). Heyd–Scuseria–Ernzerhof functional is introduced. The influences of members of “Si-O-Si” rings are considered to study atomic structures, electronic structures, and optical properties of Bi-doped optical fiber. Our results reveal that Bi-doped in 3-membered rings are main contributions to the characteristic absorption bands (around 500 nm), which will lead a red emission in Bi-doped optical fiber. Our methods will be effective to confirm bismuth-active centers for different valence states of Bi atom.