| 摘要 |
PURPOSE:To easily obtain a base material for an optical fiber having excellent thermal stability and desired refractive index distribution by spraying the raw material melt of a glass compsn., depositing the formed fine particles of the glass successively to form a porous base material and vitrifying the same to transparent glass. CONSTITUTION:The melt 1 of the glass raw material having the core compsn. and the melt 2 of the glass raw material having the clad compsn. are respectively separately put into platinum vessels 3 and are respectively held at a high temp. by electric furnaces 4. The melt 1 of the glass raw material having the core compsn. is then sprayed from a double pipe nozzle 5 and after the formed fine particles of the glass are deposited to a bar shape, etc., the melt 2 of the glass raw material having the clad compsn. is similarly sprayed to deposit the formed fine particles of the glass, by which the porous base material 6 is formed. The porous base material 6 is then vitrified to the transparent glass by a heating treatment, by which the objective base material for the optical fiber is obtd. The control of the refractive index distribution at a high degree and the easy production of the large-sized base material for the optical fiber are thereby permitted. |
