Improvement of transparency and durability to deep ultraviolet light in fluorine-doped silica glass fiber by optimizing the preform fabrication process

Abstract

Fluorine-doped silica glass fiber was fabricated as fiber-core for transmittance of deep ultraviolet wavelength region. By examining the effect of oxyhydrogen flame onto the core-glass (conventional cleaning process called fire-polishing process), it was found to create oxygen-deficiency centers. Additionally, fire-polishing process changes the distribution of fluorine concentration near core-cladding interface and leads to the deterioration of the optical characteristics of the fiber. By conducting preform fabrication without fire-polishing, the obtained fluorine-doped silica glass fiber showed high transmittance of more than 92% m -1 at 266 nm and excellent durability after 4 G pulses of 7 mJcm -2 laser irradiation.