Improved silica-core fibers in the UV-transmission

Optical fibers for UV transmission have been under intensive development for medical, industrial and other applications during the past several years. Because of this high-speed growth, the problems associated with the damage and transmission properties of silica fibers in the UV region need to be deeply solved. In this paper, in order to make silicacore fibers with excellent transmission in a UV spectral region, an improved silica-core fiber is fabricated by a new fabrication technology of UV-transmission fibers. The technology of fabricating a UV fiber using silica glass is based on two effects of previous UV irradiation and heat treatment. The structural defects and color centers are purposefully caused in silica glass by irradiation silica glass preform with UV, then the structural defects and color centers are removed by performing heat treatment in drawing tower during drawing optical fiber process. The defect generation mechanism in the silica optical fibers is investigated in the paper, and these defects termination principle is also developed. Finally, UV fibers have been tested. From these tested results, UV fibers fabricated by proposed technology have reached the level of high characteristics.