An investigation was made of the formation of Ge-related defects in glass fiber which was preformed by poling with ArF laser excitation. The electric field dependence of the induced defect concentrations was measured by using optical absorption techniques. Color centers, such as Ge electron-trapped centers and Ge E' centers, were introduced. The concentrations of induced Ge electron-trapped centers and Ge E' centers increased with increasing electric field. The conversion efficiency of Ge electron-trapped centers to Ge E' centers was found to be independent of the electric field. The results strongly suggested that the ArF laser excitation was effective in forming Ge electron-trapped centers.

M.Takahashi, T.Fujiwara, T.Kawachi, A.J.Ikushima: Applied Physics Letters, 1997, 71[8], 993-5