| 摘要 |
PURPOSE:To provide a method for producing an optical fiber base material, capable of adding a desired doping material to the optical fiber base material at an arbitrary diameter position, and a device therefor. CONSTITUTION:A method for producing an optical fiber preform 1 by feeding an oxyhydrogen flame material and silicon tetrachloride into a burner 3 and depositing the produced soot on the outer surface of the optical fiber base material is characterized by joining a pipe 9 for feeding a desired doping material to the course of a main pipe 4 for feeding the main raw material, silicon tetrachloride, disposing a switch valve 5 in the doping material-feeding pipe 9 at a position on the upper stream side of the confluence so as to enable the production of a soot mixed with the desired doping material at the desired radial position of the optical fiber preform1 by the switching of the switch valve 5. The outer diameter of the optical fiber preform 1 can remotely be measured with an outer diameter measuring device 10, and the switching operation of the switch valve 5 can thereby automatically be executed on the basis of the measured value. |
