Methods of incorporating materials of interest in glass optical waveguides

A method of incorporating within a glass optical waveguide an undissolved material of interest that is soluble in molten glass and exhibits a property of interest that would be neutralized were the material of interest dissolved includes combining pieces of a light-transmissive first glass with the material of interest. The combined first glass and material of interest are shaped within a container and heated to a temperature sufficiently high to cause the glass pieces and material of interest to mutually coalesce and form a light-transmissive core rod, but not high enough that the first glass melts and the material of interest dissolves therein. A cladding tube is heated and fused about the core rod to define a mono rod. An optical waveguide through which light propagates by internal reflection, and which incorporates the undissolved material of interest, is defined when the cladding tube comprises a glass that renders the cladding of lower refractive index than the core rod.