| 摘要 |
PURPOSE:To manufacture the title glass with a simple apparatus by heating a cylindrical jet consisting of a plurality of source gases, steam and an oxidizing agent while varying the concn. of the steam in the radius direction to deposit glass soot on a rotating starting member. CONSTITUTION:Composite jet 3 consisting of a source gas for a glass principal component, a source gas for a dopant, steam and an oxidizing agent other than steam is spouted upward from composite nozzle 1. Since the steam is spouted from concentric central nozzle 2, steam portion 4 in jet 3 whose cross-section is practically circular is diffused from the center to the periphery, resulting in a concn. gradient in the radius direction. Jet 3 is heated with external heat source 5 to form soot, which is then deposited on target surface 6 to form soot rod 7. The amount of dopant soot formed becomes the maximum at the central portion where the steam concn. is high. By sintering rod 7 a transparent glass rod having an arbitrary refractive index distribution in the radius direction is obtd. |
