| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing an optical fiber preform with the flame of a burner in a closed chamber, capable of preventing outer air from flowing in the chamber from its spaces to cause troubles such as the turbulence of the flame and the contamination of the preform with generated soot. SOLUTION: This method for producing an optical fiber preform comprises surrounding a part of a cylindrical pipe 2 and the whole body of a chamber 1 with an outer reactor 7 and subsequently controlling the inner pressures of the cylindrical pipe 2 and the outer reactor 7 at the same or slightly lower negative pressure as or than the inner pressure of the chamber 1. Thereby, it can be prevented that an outer air is flowed in the chamber 1 through the space of a joint (e) between the chamber 1 and the cylindrical pipe 2, the space of an attached portion of a burner for the core, the space of an attached portion of a burner for the clad, or the space of an attached portion of an exhaust pipe 5, etc. |
