Optical absorption of Bi2+-ODC(II) active center in Bi-doped silica optical fiber

By using first-principles calculations, oxygen deficient centers (ODC(II), ODC(I) and E′ center) with divalent bismuth were investigated in the model of silica optical fiber. Geometric structures, electronic and optical properties of the defect models were calculated by the method of GW + BSE, and the reaction path from Bi2+-ODC(II) to Bi2+-E’ center through the transition state of Bi2+-ODC(I) was plotted by CI-NEB calculations. Our results revealed that the absorption band at 1520 nm mainly attributes to the complex of Bi2+-ODC(II) in Bi-doped silica optical fiber.