| 摘要 |
PURPOSE:To provide the base material of an optical fiber having uniform bulk density by providing a burner for heating to the side of a deposition burner for depositing fine glass particles, in order to uniform the temperature distribution in the deposition part of the fine glass particles. CONSTITUTION:A burner 11 for heating a core part is provided to the center of both a deposition burner 2 for the core and a deposition burner 3 for a first cladding and placed in the same distance as the distance between the burner 2 and the porous glass base material 1. A burner 12 for heating the first cladding part is provided to the center of both the burner 3 and a deposition burner 4 for a second cladding and placed in the same distance as the distance to the burners 3, 4 from the base material 1. A burner 13 for heating the second cladding part is provided to the upper part of the burner 4 and placed in the same distance as the distance between the burner 4 and the base material 1. All burners 11, 12, 13 for heating are positioned on the same plane and only gaseous fuel is supplied. The parts apart from the center of flame of the burners 2, 3, 4 and low in the temperature are heated. The deposition parts of fine glass particles on the surfaces of a core part 1a and the cladding part 1b are regulated to the uniform temperature. |
