| 摘要 |
PURPOSE:To efficiently obtain a preform having desired thickness in a short time in producing optical perform by outer depositing method by successively changing an angle between arrangement direction of gas feed pipes of glass raw material and longer axis direction of starting member corresponding to deposition degree of glass fine particles. CONSTITUTION:Glass fine particles are deposited on a starting member 22 by using a burner 1 having plural gas feed pipes 2 of glass raw material to produce an optical fiber preform 23. In the operation, an angle between arrangement direction II-II line of the gas feed pipes 2 of glass raw material in the burner 1 and longer axis direction 15 of a starting member 22 is successively changed corresponding to deposition degree of glass fine particles to produce an optical fiber preform. Namely, in an early stage of starting of deposition of the glass fine particles, the II-II line is in parallel to the longer direction 15 so that the starting member 22 is efficiently irradiated with flame. The angle is successively changed corresponding to deposition degree of the glass fine particles and the angle between the II-II line and the longer axis direction 15 is operated and made perpendicular. |
