| 摘要 |
PURPOSE:To obtain the titled base material free from an inflection and suitable for optical communication by using an eccentric multitubed burner to eccentrically feed glass starting materials, fuel gas, etc. and carrying out flame treatment by a vapor phase axial deposition method to form a porous glass preform. CONSTITUTION:When an optical fiber base material is manufactured by a vapor phase axial deposition method, an eccentric multitubed flame burner is used as a flame burner to eccentrically feed glass starting materials, carrier gas, shielding gas and fame forming combustion gas, and flame treatment is carried out to form a porous glass preform. Quadruple-tubed burner 1 is preferably used as the eccentric multitubed burner. Burner 1 is composed of outermost cylindrical tube 3 having introduction hole 2, tube 5 put in tube 3 and having introduction hole 4, and cylindrical tubes 6, 7 eccentrically put in tube 5. |
