| 摘要 |
PURPOSE:To readily carry out etching of an interface between a core member and clad member at a low cost with a high accuracy, by introducing a fluorine compound and oxygen into a gap between the core member and the clad member before melting and integrating the members by a rod-in-tube method and heating the members. CONSTITUTION:A core member 1 is inserted into a pipelike clad member 2 and a mixture of a fluorine compound, e.g. SF6, with oxygen at a suitable ratio is introduced into a gap between both members 1 and 2, which are then heated at 1,300-1,800 deg.C from the outside of the clad member 2 by using an oxyhydrogen flame 3, etc. Thereby, the outer surface of the core member 1 and the inner surface of the clad member are etched to form a smooth and clean surface. The introduction of the fluorine compound and oxygen is then stopped and the clad member 2 is heated by the oxyhydrogen flame 3 from the outside while evacuating the interior of the members to melt and integrate the core member 1 with the clad member 2. Thereby, the aimed base material for optical fibers is obtained. As a result, the amount of etching can be controlled by the heating temperature. |
