Apparatus and method for fabricating an optical fiber preform with a large aperture

A method for fabricating large aperture optical fiber preform using a sintering apparatus for gel tube, includes the steps of: forming a uniform sol by mixing/dispersing for mixing fumed silica with deionized water, and adding a dispersing additive to form uniform sol; injecting the sol into a mold with a certain tubular form, and then gellifying the sol; demolding the tube-shaped gel from the mold; drying the tube-shaped gel; processing (or Binder burn-out & Purification) organic compounds including remaining moisture, alkali metallic impurities, and hydroxides in the gel; inserting a primary preform into the tube-shaped gel and then fastening the preform; and after arranging the gel with the primary preform therein into a sintering apparatus, sintering/over cladding the gel with the primary preform therein under vacuum atmosphere at high temperature.