METHOD AND APPARATUS FOR MANUFACTURING BASE MATERIAL FOR OPTICAL FIBER

摘要

PURPOSE:To manufacture a base material for an optical fiber having a desired refractive index distribution by a VAD method by measuring the intensities of a plurality of transmitted X-rays to detect the elemental distribution of a base material and controlling the conditions for manufacturing the material in accordance with the result. CONSTITUTION:In the manufacture of a base material 3 for an optical fiber by a VAD method, the material 3 is irradiated with a plurality of characteristic X-rays 7 having different wavelengths from an X-ray radiator 8, and the intensities of the transmitted X-rays are detected with a detector 9 to calculate the elemental distribution of the material 3 with an arithmetric device 10. In accordance with the result the flow rates 6 of SiCl4 and GeCl4 as gaseous starting materials for glass and the position of a burner 2 are properly controlled with the flow rate controlling terminal 13 and the position controlling terminal 14 of a controller 11, respectively. Thus, the material 3 having a desired refractive index distribution is manufactured.