| 摘要 |
PURPOSE:To obtain the titled single-mode base material having a refractive index distribution without widening to the bottom and having an excellent transmission characteristic with a single mode by arranging burners for a core and a clad so that the length of the core is made longer than the outer diameter of the clad. CONSTITUTION:In the production of a laminate of glass fine particles by flame hydrolysis, a burner 4 for the clad is arranged at the upper part and a burner 3 for the core is arranged at the lower part so that a porous glass body 10 for the core having a length (l) longer than the outer diameter D of a porous body 11 for the clad is grown. Discharge pipes 15 and 16 are provided on the flame blowing sides of both burners 3 and 4. Then SiCl4, GeCl4, H2, O2 and Ar are supplied to the burner 3 for the core and SiCl4, H2, O2 and Ar are supplied to the burner 4 for the clad. The glass fine particles 7 for the core and the glass fine particles 6 for the clad are formed, respectively blown and deposited on the core 10 and the clad part 11 and grown. Meanwhile, undeposited glass fine particles are sucked and discharged from the discharge pipes 15 and 16. Then the obtained porous glass body is heated, dehydrated and vitrified. |
