| 摘要 |
PURPOSE:To extend the range of starting materials for glass for forming a base material for an optical fiber, by converting porous glass for clad covering perfectly porous glass for a core into transparent glass and by converting the core part into transparent glass. CONSTITUTION:A porous base material for an optical fiber is composed of porous glass for a core and porous glass for clad covering perfectly or almost perfectly the porous glass for the core. The base material is heated in an atmosphere of gaseous chlorine in an electric furnace to convert only the clad part 3 into transparent glass. Sufficient dehydration is carried out in the stage to remove all of OH groups contained in the base material. The core part 1 is then converted into transparent glass by heating the translucent base material from the lower end with a high-temp. heat source such as an oxyhydrogen flame or a plasma flame and by rapidly cooling the heated part. Thus, a transparent base material for an optical fiber is manufactured. |
