ENVIRONMENTAL RESISTANT STEP INDEX TYPE OPTICAL FIBER

摘要

PURPOSE:To obtain a step index type optical fiber having excellent radiation resistance by incorporating a slight amt. of fluorine only in the extreme neighborhood of the boundary of a core. CONSTITUTION:This optical fiber is constituted by incorporating the slight amt. of F in only the extreme neighborhood of the surface of the core. Since the core constituted of high-purity quartz glass in the greater part of the rest is used, the characteristics of the high-purity quartz glass core are maintained and since the F exists in the extreme neighborhood of the surface of the core, a difference in viscosity in the boundary face between the core and the clad is decreased and the generation of strain at the boundary face is suppressed. An increase of transmission loss is thereby suppressed even at the time of radiation irradiation.