An object of the present invention is to provide a method for manufacturing an
optical fiber preform having a great diameter by reducing an eccentricity or a
non-circularity of a core, an optical fiber preform having an small non-circularity
and a complex refractive index profile, even with a great diameter, and an optical
fiber that is applicable as a dispersion compensating fiber. The present invention
involves a rod-in collapse process in which a glass rod is fixed within a glass
pipe (or a dummy pipe attached to an end portion) via an aligning jig. The fixation
via the aligning jig is made at one end or both ends, the aligning jig has a cylindrical
shape with or without one or more reduced diameter portions. When fixed at one
end, a heating and integrating process is preferably made from an opposite end.
Employing the glass rod and the glass pipe having a refractive index distribution,
a complex profile can be realized.