Single-mode optical, fiber and process for its production
AssigneeSchott Glaswerke
InventorUlrich Fotheringham
Life of this patent
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Abstract
A single-mode optical fiber is doped to achieve a number of desired properties and have a refractive index profile n(r). The doped fiber must at least approximate the formula: ##EQU1## in which n.sub.o means the refractive index of the matrix material and r.sub.i =i.multidot..DELTA.r. A process for the production of the single-mode optical fiber is disclosed using at least 100 layers.
Claims19
A single-mode multiple-layer fiber with a refractive index profile n(r), in which n means the refractive index of the fiber material at distance r from the axis of the fiber, and the refractive index profile is adjusted by doping of matrix material from which the fiber is predominantly made, with at least one dopant with formation of a number of layers having different refractive indices, characterized in that:
- (a) the refractive index profile n(r) is adjusted for preset values of at least one of the desired properties of chromatic dispersion, mode field diameter, attenuation and overmode cutoff;
- (b) a number m of layers of thickness .DELTA.r is greater than the number of desired properties;
- and
- (c) each layer contains just enough dopant so that the relative refractive indices, with the desired properties maintained, meet at least approximately the condition ##EQU16## in which n.sub.o means the refractive index of the matrix material and r.sub.i =i.multidot..DELTA.r.
A process for the production of a single-mode multiple-layer optical fiber, in which the fiber is designed with multiple layers having different refractive indices, and the refractive index is adjusted by using at least one dopant in the matrix material from which the fiber is predominantly made, characterized in that:
- (a) the refractive index profile n(r) is adjusted for preset values of at least one of the desired properties of chromatic dispersion, mode field diameter, attenuation, and overmode cutoff;
- (b) the number m of layers of thickness .DELTA.r is selected large compared with the number of desired properties;
- and
- (c) each layer is provided with just enough so that the relative refractive indices while maintaining the desired properties meets approximately the condition ##EQU17## in which n.sub.o means the refractive index of the matrix material and r.sub.i =i.multidot..DELTA.r.
Dependencies are inferred from the claim text.