A method of fabricating an optical waveguide fiber that includes the steps
of providing a cylindrical glass optical fiber preform having a
longitudinally extending centerline hole, and closing the hole under
conditions suitable to result in uniform and symmetric hole closure. The
method may include first plugging a first end and a second end of the
centerline hole to prevent gas flow therethrough. The method preferably
involves closing the centerline hole of the preform by drawing the
preform down into an optical waveguide fiber.