Consolidation-atmosphere influence on drawing-induced defects in pure silica optical fibers

Drawing-induced paramagnetic defects (E´centers and oxygen-associated hole centers (OHCs)) and optical absorption bands at 630 nm and in the UV region are investigated for optical fibers. These fibers are drawn from pure silica glass preforms consolidated in atmospheres containing O₂ and Cl₂. UV absorption bands at 245 nm and 275 nm are clearly observed through deconvolution of the absorption spectra of optical fibers. The defects and absorption bands are influenced by the atmosphere in the consolidation process: (1) the OHCs and the absorption bands at 630 nm and 275 nm increase the intensity with increasing O₂ content and with decreasing Cl ₂ content; (2) the E´ centers decrease under the same conditions; and (3) the absorption band at 245 nm is independent of the atmosphere