Method of Manufacturing Glass Base Material

摘要

To decrease the manufacturing cost and the transmission loss of precursor of optical fiber or preform for optical fiber, a method of manufacturing glass base material includes: forming porous glass base material which includes a dopant added core part, and an inner clad layer surrounding said core part and having a lower refractive index than the core part; transforming said porous glass base material into clear glass to be provided as a core ingot; heating and elongating said core ingot in the axial direction in an electric furnace to make a core rod; and forming an outer clad layer surrounding said core rod.