| 摘要 |
PURPOSE:To obtain a porous glass preform of uniform shape by enabling a burner supporting stand to be moved back and forth in the diametrical direction of a rodlike substrate by means of an eccentric collar in the manufacture of a base material for an optical fiber by a VAD method. CONSTITUTION:Burner 11 is set at the predetermined position, and the distance between burner 11 and the tip of a rodlike substrate is adjusted. by actuating motor 28, eccentric collar 37 inserted in long hole 36 of burner supporting stand 31 is rotated together wih rotating shaft 22, and burner 11 is moved back and forth in the diametrical direction of the substrate together with stand 31. At this time, glass starting materials, etc. are emitted from burner 11 to synthesize sootlike glass fine particles, and the particles are uniformly deposited on the lower part of the substrate to form a porous glass preform of uniform shape. Using this base material an optical fiber with little fluctuation in the refractive index distribution can be manufactured. |
