The effluence of gas opening where the effluence of gas

摘要

PROBLEM TO BE SOLVED: To provide a burner for working an optical fiber pre-form which generates no metal oxides from the burner, is not broken even when it is brought into contact with the optical fiber pre-form, and generates no back fire within the burner. ;SOLUTION: In the burner for working the optical fiber pre-form, an inner tube 2 formed of glass at least at a portion in the vicinity of a gas outlet 12 from which the assist gas flows is inserted in an outer tube 3 formed of glass at least at a portion in the vicinity of a gas outlet 13 from which the combustible gas flows. The outer tube 3 is inserted in a protective outer cylinder 1, and the portions of the inner tube 2 and the outer tube 3 are inserted in an inner empty part of the protective outer cylinder 1.;COPYRIGHT: (C)2000,JPO