| 摘要 |
PURPOSE:To obtain the titled fiber having an excellent optical transmission loss by extruding a polymer in a strand shape, into a vessel maintained to a reduced pressure through a sieve plate, thereby removing a volatile substance. CONSTITUTION:The polymer is extruded in the strand shape, into the vessel maintained to the reduced pressure by passing through the sieve plate 3, thereby removing the volatile substance contd. in the polymer. The temperatures of a passage for conveying the polymer and an apparatus 10 are maintained at a high temperature for example, 200-300 deg.C to reduce a viscosity of the polymer. The polymer is stored temporarily in a lower part of the apparatus 10, and then is extruded by a pressure of gas from an outlet 5 thereof. If necessary, the polymer is made to a fiber to form a core. And then, a clad is formed around the core coming from the apparatus 10. |
