MANUFACTURE OF GLASS BASE MATERIAL FOR OPTICAL FIBER

摘要

PURPOSE:To manufacture a glass base material for an optical fiber with fluoride glass having a small vitrification tendency by heating a glass rod for a core to a temp. close to the glass transition temp. and depositing molten glass for a clad on the surface of the heated rod in the form of a layer. CONSTITUTION:When a glass base material for an optical fiber having a waveguide structure is manufactured with fluoride glass having a small vitrification tendency, while rotating a glass rod 15 for a core with chucks 4, the rod 15 is uniformly heated to a temp. close to the glass transition temp. with a heating source 17 and kept at the temp. Glass powder for a clad is then heated and melted with a melting device 18 while moving a feeder 16 over the full length of the rod 15, and the molten glass is uniformly deposited on the surface of the rod 15 in the form of a layer and rapidly cooled. Since a glass layer for a clad can be formed on the surface of the rod 15 without causing crystallization, a glass base material for an optical fiber having a waveguide structure can be easily manufactured with fluoride glass requiring rapid cooling for vitrification.