Processing Induced Defects in Silica Glasses

The effects of the fiber drawing process on defects of silica fibers have been investigated. This study has focused on the oxygen deficient centers (ODCs) and E' centers induced by the fiber drawing process in low-OH oxygen deficient silica. The ODCs induced by the fiberization process have been investigated using the optical absorption band at 248 nm. In case of E' centers, optical absorption and electron spin resonance (ESR) have been used. The population of ODCs in the neck-down region has also been investigated. The concentration of ODCs are observed to increase dramatically within the neck-down region.