| 摘要 |
PURPOSE:To reduce the scattering loss of infrared ray and to increase the strength of a fiber by forming a hollow thin pipe or fiber for clad connection from ionic crystal or metal, filling the pipe with ionic crystal molten substance as a core and cooling the moldings gradually to complete single-crystalization. CONSTITUTION:Ionic crystal 1 such as LiF and CaF is melted in a crucible 2 and the hollow cylindrical seed crystal of the ionic crystal whose size is made to consist with that of a concentric double pipe die 4 is put on the die 4, dipped in the molten ionic crystal through the die 4 and pulled out from the crucible 1 gradually to obtain a hollow fiber 5. A drum which the fiber 5 is wound around is installed inside of a large furnace 10, one end of the fiber 10 is dipped in ionic crystal molten substance 9, a core, and the other end is connected to a trap 8 to fill the fiber 5 with the molten substance with a vacuum pump 7. After cooling the fiber gradually and transferring it to another furnace, the fiber 5 is pulled out from the furnace gradually to get a single crystallized optical fiber while keeping the temperature just under the melting point of the crystal. When a metallic hollow pipe is used as a clad fiber, the process after the filling of core crystal molten substance is repeated in the same manner as mentioned above. |
