Abstract: An optical fiber has a core with a diameter dc and a reflective index nc; a primary cladding concentrically surrounding the core and having an outer diameter dpc and a refractive index npc less than the core refractive index nc; and a secondary cladding concentrically surrounding the primary cladding and having an outer diameter dsc and a refractive index nsc less than the primary cladding refractive index npc.

Abstract: An optical fiber includes a substantially transparent core that carries a light signal, a substantially transparent cladding surrounding the core, and within the cladding and distinct from the core, at least one visualization member facilitating visualization of one or more elements of the fiber structure.

Abstract: A hybrid method of and apparatus for producing a structure capable of being drawn into an optical fiber. The method includes the steps of conducting vapor-phase reactants into an interior region of a glass tube, conducting aerosol form reactants into the interior of the glass tube. The tube is exposed to a heat, thereby causing a reaction among the vapor-phase and aerosol reactants. The reaction yields a product, in a solid form, within the tube. The apparatus includes a reaction tube, a vapor-phase reactant conduit, an aerosol-form conduit, and a heat source. The vapor-phase and aerosol-form reactant conduits facilitate introduction of vapor-phase and aerosol-form reactants into the reaction tube. The aerosol-form reactants are introduced proximate to a reaction zone created by the heat source. The aerosol-form reactants conduit and heat source travel the axial length of the reaction tube.