| 摘要 |
PURPOSE:To reduce the loss in the range from the ultraviolet region to the infrared region, by constituting the core and the clad with ionic crystal. CONSTITUTION:Groups consisting of the halogenide of the alkali metal such as LiF, the halogenide of the alkaline earth metal such as CaF2, the halogenide of the copper group element such as Cul2, and the halogenide of the zinc group element such as ZnCl2 are selected properly and are used as ionic crystal constituting the core and the clad. In production of the optical fiber, CaF2 is loaded into core crucible 1 and is heated to form core melted material 2. Core edge 3 is so adjusted that the temperature of the core growing part at the tip is, for example, 1,380 deg.C, and material 2 is pulled up in the Ar gaseous atmosphere in 12cm/min speed to obtain core crystal 4 of 100mumphi. This crystal 4 is entered into clad crucible 6 where LiF is melted at, for example, 950 deg.C and is pulled up from clad edge 7 which is so adjusted that the inside diameter, the outside diameter, and the temperature of the clad growing part at the tip are 320mum, 500mum, and 890 deg.C respectively, thereby obtaining the 350mum optical fiber consisting of the CaF2 core and the LiF clad. |
