Fluorine and chlorine effects on radiation-induced loss for GeO2-doped silica optical fibers

Fluorine and chlorine effects on radiation-induced loss associated with the preexisting defects have been investigated. It is found that preexisting defects in fibers are closely related to radiation-induced loss. Fluorine and chlorine doping in GeO
2
-doped silica core optical fibers decreases GeO absorption at 0.24 μm and ESR signal intensity due to germanium-related paramagnetic defect. Fluorine and chlorine doping is effective in decreasing the radiation-induced losses in GeO
2
-doped silica core optical fibers.