| 摘要 |
PURPOSE:To reduce the falling width of the refractive index distribution of an optical fiber at the central part by heating a hollow glass pipe while feeding a gas contg. a fluorine compound into the pipe in a process for making a base material for an optical fiber solid. CONSTITUTION:While turning a quartz pipe 1 in the direction of an arrow 7, gaseous starting material is fed in the direction of an arrow 6 and heated with a burner 3 moving back and forth in the directions of arrows 4, 5 to form a glass layer 2 in the pipe 1. The feed of the gaseous material is then stopped, and while etching the inside of the deposited glass film 2 by feeding a gas contg. a fluoride such as SF6 of CF4 in the direction of the arrow 6 and moving the burner 3 back and forth, the pipe 1 is made solid by heat melting. Thus, an optical fiber with a satisfactory refractive index distribution is manufactured in a high yield. |
