Optical waveguide glass fiber flame processing
AssigneeAmerican Telephone and Telegraph Company, AT&T Bell Laboratories
InventorJohn T. Krause
Life of this patent
Estimating the term…
Abstract
In the interest of reducing the effect on tensile strength of flame processing of a silica-based optical fiber waveguide, such processing is by a method in which a significant flow of oxygen surrounds a flame produced by combustion of hydrogen, deuterium, ammonia, or deuterated ammonia. Flame processing may be for purposes such as, e.g., fiber drawing, fiber fusing for the sake of lateral coupling, refractive index modification by the diffusion of dopants, and fiber splicing in the manufacture of long lengths of fiber. Even though there is no use of chlorine, at least 80 percent of spliced fibers have a tensile strength greater than or equal to 500 kpsi (3.45 GPa) as is desirable in optical fiber cable manufacture.
Claims14
Method for making at least one silica-based optical waveguide glass fiber having a dopant-induced core-cladding waveguiding structure,
- said method comprising a step of heat processing at least a portion of at least one silica-based optical waveguide glass fiber segment, heat processing being by means of a flame which results upon combustion in a flow of gases,
- said flow comprising a first flow portion and a second flow portion surrounding said first flow portion,
- said first flow portion comprising a significant amount of one or several combustible gases selected from the group consisting of hydrogen, deuterium, ammonia, and deuterated ammonia,
- said second flow portion comprising a significant amount of oxygen,
- said method being characterized in that no appreciable amounts of chlorine are present in said flow and said second flow portion having volume and velocity significantly in excess of volume and velocity as required for combustion.
Dependencies are inferred from the claim text.