| 摘要 |
PURPOSE:To produce a preform optical fibers, having a low loss and capable of controlling refractive index, by feeding a raw material gas into a burner repeating the movement in the oblique direction and stop in a plane including the rotation axis of a deposited body while changing the flow rate of the raw material gas according to the position of the burner. CONSTITUTION:Fine glass particles are produced from one or more burners 2 and 3 to deposit a soot preform 4 on a seed rod 1 while rotating and moving the seed rod 1 in the direction of rotation axis and the resultant deposited body is then transparentized and vitrified to afford the aimed preform for optical fibers. In the process for producing the preform for the optical fibers, at least one burner 3 is fixed on a guide 61 and moved in the oblique direction to the rotation axis in a plane including the above-mentioned rotation axis while repeating the high-speed movement for a given distance and stop for a given time. The flow rate of the raw material gas to the above-mentioned burner 3 is simultaneously changed as a function of the position of the burner 3. Thereby the aimed preform for optical fibers capable of readily providing a low loss is obtained without causing dip, etc., in a refractive index distribution. |
