| 摘要 |
Provided is a method for manufacturing an optical fiber that is inserted into an insertion portion of an endoscope and guides light, wherein inside an upright fiber drawing furnace, inside a hollow clad tube including a clad glass having a viscosity eta1 of 5.0<Log eta1<7.0 at a temperature at which a viscosity eta2 of a core glass becomes Log eta2=3.5, the core glass in a fluidized state runs down by gravity, whereby the core glass and the clad glass are integrated. |
