Optical waveguide fabrication method

摘要

A method of fabricating an optical waveguide comprising a plane substrate made of a material having a relatively low refractive index, a plane light propagation layer made of a material having a higher refractive index than the substrate, inserted between two strips of a material having a lower refractive index than its own, and a plane light confining layer of a material having a lower refractive index than the propagation layer. At least one of the layer, meaning either the propagation or the confinement layer, is obtained by causing to circulate in a tube of pure silica the vapors of a gaseous compound of silicon transformable into silica and of a gaseous compound of a doping agent transformable into one of its own oxides and heating said vapors sufficiently to obtain the deposit of a layer of doped silica having a refractive index different from that of the pure silica. Modifacations to the refractive indices can be obtained by either diffusing or implanting dopants, or alternatively by selective elimination of dopants.