A method for manufacturing an optical fiber preform includes the steps of depositing an inner cladding and a central core inside a fluorine doped silica tube and thereafter collapsing the silica tube to form a primary preform. The fluorine doped silica tube has a cross section area that is no more than about 15 percent smaller than the cross section area of the resulting primary preform. The present method facilitates reduced-cost manufacturing of a high-capacity optical fiber preform, which may be drawn to produce an optical fiber having reduced transmission losses.