PURPOSE: To provide an optical fiber having low eccentricity and small transmission loss without deteriorating the straightness of the glass rod due to softening of the glass rod, by surface-treating a starting core member made of a glass rod not adopting heating with an oxyhydrogen flame, etc., satisfactorily removing dust on the surface of the core member by the surface treatment and using a base material for an optical fiber produced with the core member.
CONSTITUTION: When a starting core member made of a glass rod is surface- treated and a clad part is formed around the core member by outside deposition to produce a base material for an optical fiber, the core member is surface- treated by jetting distilled water on the surface of the glass rod.
HORIKOSHI MASAHIRO
SHIOYA KEIICHIRO
HARADA KOICHI
TAKAHASHI KOICHI
