MANUFACTURE OF OPTICAL FIBER

摘要

PURPOSE:To obtain an optical fiber having low loss and sufficiently thick clad, by inserting a reduction process between the forming process and the dehydration process of a porous glass preform in VAD process. CONSTITUTION:A porous glass preform manufactured by VAD process is reduced to eliminate the dopant added e.g. to raise the refractive index. The refractive index of the surface layer is lowered by this process. The obtained glass preform is dehydrated, vitrified to transparent glass, drawn, covered with a jacket and spun to obtain an optical fiber having low loss and sufficiently thick clad.