| 摘要 |
PURPOSE:To produce the title base material without any crystalline structure and with high dimensional precision by compressing molten fluoride glass, and passing the glass through a nozzle kept at a specified temp. to continuously quenching and solidifying the glass in the production of the fluoride fiber base material. CONSTITUTION:When the optical fiber base material consisting essentially of a heavy metal fluoride such as ZrF4 is produced, the melt 1a of core glass is charged in the inner crucible 5 of a double crucible 4, and the melt 1b of clad glass is charged in the outer crucible. A cooling nozzle part 3 is formed at the lower part of the crucible 4, the crucible 4 part is kept at a temp. TM higher than the m.p. Tl of the fluoride glass in the crucible, the temp. TM of the nozzle part 3 is made higher than the glass-transition temp. T0 and lower than the crystallization temp. TC. Both glass melts 1a and 1b are extruded from the cooling nozzle 3 while being compressed, and a fluoride optical fiber base material without any crystalline structure, having a core part and a clad part, and with excellent dimensional precision is produced. |
