METHOD OF MANUFACTURING SILICA GLASS OPTICAL WAVEGUIDE PREFORM

摘要

An extruding apparatus having at least two independent inlet ports (21, 22), one outlet port (23) communicating with the inlet ports (21, 22), and at least two passages (24, 25) connecting the inlet ports (21, 22) with the outlet port (23), in which a section of a joint portion (26) of the passages (24, 25) has a central portion and an outer peripheral portion which are concentrically arranged, is prepared. A core material (31) is supplied to one of the passages (24) communicating with the central portion of the joint portion (26) from a corresponding inlet port (21), and a cladding material (35) is supplied to the other passage (25) communicating with the outer peripheral portion from a corresponding inlet port (22), thereby causing the two materials (31, 35) to join each other at the joint portion (26). An integral shaped body having a portion corresponding to a core at its central portion and a portion corresponding to a cladding around the central portion is extruded from the outlet port. Water and a binder and other impurities are removed from the shaped body, and the resultant body is consolidated.