| 摘要 |
PURPOSE:In producing a porous parent material for optical fiber by soot piling method such as vapor phase axial deposition method, etc., to obtain stably a parent material having high bulk density, by piling glass fine particles while irradiating them with microwave having a specific frequency. CONSTITUTION:The burner 11 for synthesizing glass fine particles is provided with hydrogen of combustion gas and oxygen of combustion improving gas to form the flame 12, a glass raw material is fed to it, glass fine particles are formed by flame hydrolysis, the glass fine particles are sprayed to the tip of the starting material 14 which is pulled up while being rotated, to produce the porous parent material 13 for optical fiber. In the operation, the microwave generator 15 is set, microwave having frequency in 500-3,000MHz is produced by controlling the microwave by the control device 17 and the glass fine particles are piled while irradiating the piled face 18 of the glass fine particles of the porous glass parent material 13 for optical fiber with the microwave introduced through the wave guide 16. |
