| 摘要 |
PURPOSE:To prepare an optical fiber preform having a specified distribution of glass raw material by sensing the variation of growth at the lowermost part of a deposited particulate glass body in the horizontal direction due to an oxyhydrogen flame burner and correcting the oxyhydrogen flame burner in the horizontal direction. CONSTITUTION:Gaseous glass raw material is flame-hydrolyzed in a muffle furnace 1 by ejecting the raw material from the oxyhydrogen flame burner 2 and deposited particulate glass 4 is grown on a tip end of a supporting rod 3 which rises up with revolution to prepare a bar-shaped optical fiber preform. In this process, when the lowermost part of the deposited glass body 4 is shifted in the horizontal direction during the growth of the deposited glass body 4, the amt. of shift is sensed by the sensors 12, 13 for sensing the position in the X-axis and Y-axis. Then, a pulse motor 14 is controlled based on the sensing signal through a control board 16, and automation stages 10, 11 for shifting in X- and Y-axis direction mounting the oxyhydrogen flame burner 2 are shifted in the horizontal direction. By this way, the relative position of the lowermost part of the deposited glass body 4 to the oxyhydrogen flame burner 2 is maintained constantly, and optical fiber preform having uniform distribution of refractive index is obtd. stably. |
