Method of producing a strong optical fiber

Abstract

In a method of making a strong fiber waveguide in which a preform is heated and pulled to make the fiber, the improvement includes adding to the preform at least one dopant capable of creating a mechanical stress profile in the preform and at least another dopant capable of creating an index of refraction profile in the preform, and varying the dopants added to produce a composition profile so that the composition profile varies radially from the center to the surface to form a core, an intermediate clad layer having an index of refraction lower than the core, and a surface layer which is in compression having a thermal expansion coefficient smaller than the core and having a predetermined thickness less than 10% of the radius of the core, the compression being greater than 20,000 psig.

Dependencies are inferred from the claim text.