| 摘要 |
PURPOSE:To manufacture an optical fiber having low light-transmission loss, by etching the surface of a core-forming porous glass preform formed on a rod with the flame of an oxyhydrogen burner fed with a fluoride-containing gas, and at the same time, depositing glass soot to the rod to form the clad of the optical fiber. CONSTITUTION:An oxyhydrogen flame burner 1 having a multiple-wall structure is supplied with a glass-forming gas, H2 gas, O2 gas, Ar gas, etc. separately. The formed glass soot such as SiO2, P2O5, GeO2, etc. is deposited to the lower end of the rod 2 which is rotated around its axis and shifted upward, to form a porous glass preform 3 which forms the core of an optical glass fiber. The preform is heated, according to its growth, with the flames of the second and the third oxyhydrogen flame burners 4 and 5 having multiple-wall structure and placed above the burner 1. The burner 4 is supplied with a fluoride gas together with H2 gas, O2 gas and Ar gas and etches the surface of the preform 3 to obtain a porous glass preform 3' having clean surface. Glass soot is deposited to the preform 3' with the burner 5 to obtain a porous glass preform 6 which forms the clad of the optical glass fiber. |
