| 摘要 |
PURPOSE:To obtain a uniform optical fiber preform having abrupt difference in refractive index, by dispersing specific silica fine particles into at least one of raw material sols for clad and core to give sols, molding and sintering the sols by sol-gel method. CONSTITUTION:A dopant is supported in a hydrolyzed solution of an alkyl silicate with an acidic catalyst to give silica fine particles (A) having 0.01-100mum average particle diameter. Then, ethyl silicate, etc., is hydrolyzed with HCl, etc., to give a raw material sol (B) for core. Then, ethyl silicate, etc. is hydrolyzed with HCl, etc., the component A is dispersed into the hydrolyzate to give a raw material sol (C) for clad. Then the component is cast into a cylindrical container 1 o a rotary device, rotated, gelatinized the component B is cast into a hollow part of the cylindrical pipe and gelatinized to give a gel (D) of a clad-core integrated type. Then the integrated gel is dried and sintered. |
