| 摘要 |
PURPOSE:To produce a long-sized base material for an optical fiber with a small loss economically by filling a pipe for a clad contg. a core material with an atmosphere of a gas contg. halogen under reduced pressure, heating the pipe to a proper temp. and making it solid. CONSTITUTION:A rotary connector 6 is attached to one end of a pipe 2 for a clad with a dummy pipe 11 in-between and they are set in a glass lathe 1. A core material 3 having a dummy rod 10 attached to the tip is put in the pipe 2 and set through supports 4. A gas contg. fluorine such as SF6 is introduced into the pipe 2 from a line 5 and passed through the gap between the pipe 2 and the core material 3, and while the pipe 2 is rotated, one end of the pipe 2 is melted by heating with an oxyhydrogen burner 8 and sealed. The pipe 2 is then evacuated with an exhaust system 9 and the other end of the pipe 2 is melted and sealed. The both and sealed pipe 2 for a clad filled with an atmosphere of the gas contg. fluorine under reduced pressure is put in an electric furnace 12 for drawing, heated to >=1,900 deg.C and made solid to obtain a base material for an optical fiber. |
