Method of elongating optical fiber base material, and apparatus for elongating the same

A method of elongating optical fiber base material comprising:

• heating and softening base material ingot in such as an electric furnace;
• drawing said ingot with a pair of pinch rollers;
• and elongating the ingot to make base material rod having a smaller diameter than said ingot, wherein using an untapered shaft having a reference edge face which is parallel to the elongating direction, said pinch rollers are pushed against the reference edge face to be fitted and fixed to the untapered shaft, and wherein the position of the groove center of facing roller grooves respectively formed on the surfaces of said pair of pinch rollers is adjusted with a positioning adjustment apparatus which supports said pinch rollers.

An apparatus for elongating optical fiber base material, which heats and softens base material ingot in such as an electric furnace;

• draws with a pair of pinch roller;
• and elongates to make base material rod having a smaller diameter than the ingot, comprising said pinch rollers which are made of metal, and respectively have either a roller groove having a curvature radius which is larger than the outer diameter of said base material rod or a V-shaped roller groove having the cross section consisting of straight lines on the surfaces of said pinch rollers.