| 摘要 |
PURPOSE:To prepare the titled parent material having no unevenness of the refractive index distribution at the boundary part between a core and a cladding parts, by making the soot of a core part grow in a bar state and changing it into transparent glass, depositing and piling the soot of a cladding part on the core part and changing it into transparent glass. CONSTITUTION:SiCl4, GeCl4, O2, H2, etc. in a given ratio are jetted from the burner 15 for core in such a way that SiO2 and a dopant such as GeO2, etc. are formed by flame hydrolysis. While, N2 or O2 is introduced from the equilibrium feed pipe 18 to the combustion chamber 14 for core and discharged from the exhaust pipe 19 in order not to make the dopant, etc. flow from the through hole 27 into the combustion chamber 13 for cladding. The soot 16 to be changed into a core part is made into transparent glass by the combustion furnace 17 for core and grown in a bar state. While, glass raw material is subjected to flame hydrolysis by the burner 20 for cladding, and the prepared soot 22 of SiO2 is deposited and piled around the core part 21. It is changed into transparent glass by the combustion furnace 23 for cladding, and the meadow bar 26 is raised while being rotated, to prepare continuously the parent material 28 for optical fiber. |
