Influences of Bi and Yb ions on the emission efficiency of an Er-doped silica optical fiber

Abstract

We investigate the spectral characteristics of three kinds of home-made active silica fibers, namely, Er-doped fiber (EDF), Bi/Er co-doped fiber (BEDF), and Bi/Er/Yb co-doped fiber (BEYDF), and thus explore the influences of Bi and Yb ions on the absorption and emission performances in the EDF. Compared with the EDF, the absorption cross section at 980 nm and the fluorescent lifetime at 1535 nm in the BEDF are enhanced by 1.2 × 10−25 m2 and 0.68 ms, respectively. Found that the fluorescent intensity in the BEDF is higher, and the emission slope efficiency of Er ions in the BEDF is more than doubled. Moreover, compared with the BEDF, the absorption intensity and bandwidth around 980 nm in the BEYDF are significantly enhanced and broadened, and its fluorescent lifetime at 1535 nm is improved by 1.08 ms. Their fluorescent intensities are increased with the increase of the pump power. Also found that the emission slope efficiency of Er ions in the BEYDF is more than doubled. Furthermore, their local microstructural models are also built up, and their energy levels and excited state characteristics are analyzed based on the density functional theory. These results indicate that co-doping Bi and Yb ions into the EDF could improve the optical characteristics of Er ions, especially the emission efficiency, which is potentially applied in optical amplifier and laser systems, and so on.