Method of producing optical waveguide

摘要

The present invention relates to a method of producing an optical waveguide by melt-drawing a transparent glass rod which has been produced by collapsing a doped porous glass rod. The glass rod is doped with refractive index enhancing dopant materials by depositing said material on the surface of the micro-pores wherein a waveguide having higher mechanical strength and lower transmission loss is obtained upon drawing said glass rod to a fiber. The drawing is performed at a temperature very close to the melting point of the outermost portion of the rod without causing any overmelting and resultant bubbling in the core portion. The drawing process is facilitated by matching the viscosity and softening characteristics of the outer, lower refractive-index portion of the rod to that of the central higher-refractive-index portion.