| 摘要 |
PURPOSE:To prepare optical fiber having little dispersion loss in a wide range of wavelength by forming a porous glass body consisting of an SiO2+GeO2 layer, an SiO2 layer, and an SiO2+GeO2 layer from central part of the glass body toward the external layer by the flame hydrolysis, and drawing after vitrifying in gaseous F2 atmosphere. CONSTITUTION:SiCl2, GeCl4, H2 and O2 are jetted from a multilayerd burner to the tip end of a revolving quartz bar, and above-described chlorides are bydrolyzed in the oxyhydrogen flame to cause deposition of fine glass particles consisting of SiO2 and GeO2 having high refractive index. Then, fine particles of SiO2 are deposited and accumulated to the outside of the above-described fine glass particle layer by jetting SiCl4, H2, and O2. Succeedingly, fine particles of SiO2+GeO2 are deposited again similarly as the first deposition, and obtd. porous glass is dehydrated with He and gaseous chlorine, then vitrified in a mixed atmosphere of SF6 and He. After drawing the vitrified porous glass to a specified diameter, a quartz tube is covered with the drawn material and formed to one body by heating with oxyhydrogen flame. Thus, a parent material for optical fiber having low dispersion loss of light having 1.3-1.7mum wavelength range is obtd. |
