Back to results
US 8,731,358 B2Granted
Multi-cladding fiber
OwnerClaude Pare, Pierre Laperle +2inventors
InventorsClaude Pare, Pierre Laperle, Huimin Zheng, Andre Croteau
Life of this patent
Estimating the term…
Abstract
Multi-cladding optical fibers to be used in the context of fiber amplifiers and fiber lasers are described herein. Embodiments of optical fibers include a rare-earth doped core into which the signal field is to be amplified. The doped core is surrounded by multiple claddings that guide the pump field to be absorbed by the reactive core material. The first cladding has a depressed refractive index to improve high-order mode bending losses without incurring significant fundamental mode bending losses.
Claims20
A multi-cladding large-core multimode optical fiber comprising:
- a longitudinally extending multimode core with low numerical aperture having at least a portion thereof that is rare-earth doped, the core having a core refractive index and a diameter, the diameter being at least 30 μm;
- a first cladding surrounding the longitudinally extending core, the first cladding having a first cladding refractive index lower than the core refractive index;
- a second cladding surrounding the first cladding, the second cladding having a second cladding refractive index higher than the first cladding refractive index and lower than the core refractive index;
- at least one intermediate cladding surrounding the second cladding;
- and
- an external cladding surrounding the at least one intermediate cladding, the external cladding having an external cladding refractive index lower than the second cladding refractive index,
- whereby, for a given diameter of the core, a margin is increased between a first bending radius causing a threshold bending loss in a fundamental mode of the optical fiber and a second bending radius causing the threshold bending loss in higher-order modes of the optical fiber.
4 more elements
Dependencies are inferred from the claim text.