PRODUCTION OF PARENT MATERIAL FOR OPTICAL FIBER

PURPOSE:To correct a degree of revolution of a core material for optical fiber easily and in a short time in a stage of producing a parent material for the optical fiber by an external deposition process by correcting a position in the horizontal direction of the core material of the optical fiber in relation to a revolving shaft, and an angle thereof. CONSTITUTION:A porous parent material for optical fiber is produced by revolving a core material 5 by causing a hydrolytic reaction by blowing oxy-hydrogen flame contg. a parent material of glass onto external periphery of the core material 5, and depositing a porous glass body to the core material 5. A device 2 for adjusting the horizontal position and a device 3 for adjusting the angle are provided to a holder for the top part of the core material 5, adjusting thus the horizontal position of the core material in relation to the revolving shaft 1 and the angle of the core material 5 to the revolving shaft 1. Thus, the degree of revolution of the core material 5 is corrected and inexpensive optical fiber having no eccentric core and having high performance is obtd.