Radiation Effect on Optical Properties of Bi-Related Materials Co-Doped Silica Optical Fibers

Three kinds of Bi-related materials co-doped silica optical fibers (BRDFs), including Bi/Al, Bi/Pb, and Bi/Er co-doped fibers, were fabricated using atomic layer deposition (ALD) and modified chemical vapor deposition (MCVD). Then, the effect of irradiation on the optical properties of BRDFs was investigated. The experimental results showed that the fluorescence intensity, the fluorescence lifetime of BRDFs at the 1150 nm band, increased significantly with low-dose treatment, whereas it decreased with a further increase in the radiation dose. In addition, the merit Mα values of the BRDFs, a ratio of useful pump absorption to total pump absorption, decreased with an increase of the radiation doses. The Verdet constants of different doped fibers increased up to saturation level with increases in the radiation dose. However, for a Bi-doped fiber, its Verdet constant decreased and the direction of Faraday’s rotation changed under low-dose radiation treatment. In addition, the Verdet constant increase of the Bi-doped silica fiber was much faster than that of other single mode fiber (SMF) and Pb-doped silica fibers treated with high-dose radiation. All of these findings are of great significance for the study of the optical properties of BRDFs.