Reduced polarization mode dispersion fiber
AssigneeCorning Incorporated
InventorsXin Chen, Ming-Jun Li
Life of this patent
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Abstract
Disclosed is an optical waveguide fiber having a reduced PMD and a method of making the optical waveguide fiber. The optical waveguide fiber in accord with the invention has a particular spin pattern impressed upon the optical waveguide fiber during the drawing step. The spin pattern causes the fast axis of birefringence to rotate along the long axis of the optical waveguide fiber. The spin functions in accord with the invention provide for reduced PMD even in cases in which draw speed, spin magnitude, or modulation parameter vary while the spin pattern is being impressed upon the optical waveguide fiber.
Claims17
An optical waveguide fiber having reduced polarization mode dispersion comprising:
- a core region bounded by a clad layer, said optical waveguide fiber having a birefringence having a fast axis that varies in direction from point to point along at least a portion of the length of said optical waveguide fiber, the variation in direction of the fast axis being in accord with a pre-selected pattern formed in the optical waveguide fiber by a spin function, α(z), wherein the spin function α(z), the spin magnitude, and the modulation parameters are selected to provide, for a fiber having a beat length greater than or equal to about 0.5 meters, a polarization mode dispersion reduction factor which remains less than or equal to 0.50 when the spin magnitude varies up to about 35% of a target spin magnitude value.
A method of making an optical waveguide fiber having reduced polarization mode dispersion comprising the steps:
- a) drawing said optical waveguide fiber from a preform;
- and,
- b) during at least a portion of said drawing step, causing relative rotation between said optical waveguide fiber and said preform in accord with a spin function α(z), wherein, α(z)=α0[f1(γ0z+γ1f2(γ2z))×{f3(γ3,γ4z)}], where z is distance along the long axis of the optical waveguide fiber, α0 is spin magnitude, f1, f2, and f3 are periodic functions, and γ0, γ1, γ2, γ3, γ4 are modulation parameters, the periodic functions, the spin magnitude, and the modulation parameters selected to provide, for beat lengths greater than or equal to about 0.50 meters, a polarization mode dispersion factor less than or equal to 0.5, and α0 can vary by 30% to 35% of a target value.
Dependencies are inferred from the claim text.