Apparatus for manufacturing optical fiber preform, method for manufacturing optical fiber preform, optical fiber preform and optical fiber

Abstract

The present invention intends to reduce unevenness on a surface of an optical fiber preform. The apparatus for manufacturing an optical fiber preform including a support portion rotating a core rod at a rotation speed r around a rotation axis of the core rod extending in a longitudinal direction of the core rod and at least one burner array including N sets (N is an integer of 2 or more) of burners provided at intervals of a distance d and a material ejection port, and moving around the core rod at a speed v in the longitudinal direction to form a porous glass portion on an outer periphery of the core rod. A rotation number (L+x) of the core rod when the burner array moves the distance d in the longitudinal direction is represented by rd/v=L+x where the L is an arbitrary natural number and the offset x is greater than −0.5 and less than or equal to 0.5, an absolute value of the offset x is greater than 2/(2N+1) and less than 3/(3N−1).

Dependencies are inferred from the claim text.