Process for producing silica glass plate having controlled refractive index distribution

摘要: A process for easily producing a silica glass plate having an internal refractive index distribution suitable planar optical waveguide involves carrying out the following steps. (a) porous gel produced by sol-gel method is kept in reactor, pressure of which reduced to substantially vacuum state. (b) Germanium tetrachloride gas introduced into reactor at partial appropriate establish absorption equilibrium between desired concentration germanium said and introduced. (c) The step so as desorb from surface plate. (d) described brought contact with water within or outside fix distribution. (e) calcined temperature not less than 900° C. render it nonporous.