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US 6,411,762 B1Granted
Optical fiber with irregularities at cladding boundary
AssigneeScientific-Atlanta, Inc.
InventorsDouglas Anthon, Chris Emslie, Peter Maton
Life of this patent
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Abstract
An optical fiber (10) made with a central core (12), a first cladding layer (16), and a second cladding layer (18) having a series of perturbations or irregularities formed into the otherwise generally circular outer boundary of the first cladding layer (16). The irregularities in the first cladding layer (16) interrupt the propagation of skew rays and encourage coupling into the core (12).
Claims6
An optical fiber, comprising:
- a centrally disposed core region adapted to absorb radiation at a first wavelength and provide gain at a second wavelength, the radiation having at least one mode;
- an intermediate cladding layer disposed around the core region,
- wherein the intermediate cladding layer comprises:
- an inner transparent region adjacent to the core region;
- and
- an outer absorbing region adjacent to the first cladding region, the outer absorbing region absorbing radiation at a predetermined wavelength, wherein the outer absorbing region selectively attenuates modes propagating in the core region in favor of propagation of a fundamental mode of the optical fiber;
- a first cladding layer having an outer boundary and disposed around the intermediate cladding layer, the first cladding layer having a plurality of irregularities formed at least along the outer boundary such that the outer boundary is radially constrained and quasi-circular;
- and
- a second cladding layer disposed around the first cladding layer,
- wherein the refractive index of the intermediate cladding layer is between that of the core region and the first cladding layer.
7 more elements
A method of fabricating an optical fiber, the method comprising the steps of:
- obtaining a first preform comprising an inner layer, an outer layer, and a boundary between the inner and outer layers;
- drilling a plurality of holes within the inner layer adjacent to the boundary;
- forming a center hole at the center of the first preform within the inner layer;
- inserting a second preform through the center hole of the first preform;
- and
- drawing the first and second preforms such that the boundary between the inner and outer layers collapses into each hole to form a plurality of irregularities along the boundary, wherein the boundary is formed into a radially constrained, quasi-circular shape.
3 more elements
Dependencies are inferred from the claim text.