| 摘要 |
PURPOSE:To prepare optical fiber contg. little oxygen defficiency and little OH group formed therein by heat-treating optical fiber immediately after spinning in O2 atmosphere and allowing the fiber to contact with a clad material. CONSTITUTION:Optical fiber 12 drawn from a parent material 10 is introduced into a heating furnace 24 while flowing O2 continuously therethrough at ca. 600cc/min flow rate, and the fiber is heat-treated at ca. 1,200 deg.C then passed through a coater 14 to coat a clad material thereon. Since, by this method, oxygen defficiency in the fiber is reduced and the degree of increase of OH group is retarded even if diffusion of generated gaseous H2 occurred, improved optical fiber causing hardly increase of transmission loss for a long period is obtd. |
