A method of incorporating within a glass optical waveguide a material of interest having a property of interest that would be neutralized by exposure to molten glass 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 neutralizes the property of interest. 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 material of interest, is defined when the cladding tube comprises a glass that renders the cladding of lower refractive index than the core rod.