| 摘要 |
PURPOSE:The starting rod is melted in its heating part of the starting gases for the optical fiber and ultrasonic waves are applied to the starting rod to remove the occluded gases whereby optical fiber which is free from fine bubbles and has high purity and low optical loss is obtained. CONSTITUTION:A carbon dioxide laser for the core deposition 8, a gas nozzle for feeding SiCl2, GeCl4 and oxygen, another carbon dioxide laser for clad deposition 10 and another gas nozzle for feeding SiCl4 and oxygen 11 are used. At this time, ultrasonic waves are applied to the starting rod, as it is heated up to the temperature at which the fiber starting materials melt. The cavitation effect of the ultrasonic waves excludes the gases dissolving in the starting materials for optical fiber. In this state, high silicic acid glass for the core preform is allowed to grow from the top end of the starting rod 1. After the high silicic acid glass rod 12 for the core grows at some extent, the glass rod 12 is irradiated with a carbon dioxide laser from the side to allow the clad preform, i.e., the quartz glass for the clad to deposit thereon. |
