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US 7,924,500 B1Granted
Micro-structured fiber profiles for mitigation of bend-loss and/or mode distortion in LMA fiber amplifiers, including dual-core embodiments
AssigneeLockheed Martin Corporation
InventorJohn D. Minelly
Life of this patent
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Abstract
An apparatus and method for compensating for mode-profile distortions caused by bending optical fibers having large mode areas. In various embodiments, the invention micro-structures the index of refraction in the core and surrounding areas of the inner cladding from the inner bend radius to the outer bend radius in a manner that compensates for the index changes that are otherwise induced in the index profile by the geometry and/or stresses to the fiber caused by the bending.
Claims37
A method comprising:
- forming a waveguide amplifier having a gain section that includes a coiled waveguide, wherein the waveguide has a first diameter of a cross section of the waveguide and a second diameter of the cross section of the waveguide that is perpendicular to the first diameter, wherein the cross section of the waveguide is perpendicular to an axis of optical propagation in the waveguide, the forming of the waveguide amplifier including forming an asymmetry in a first refractive-index profile across the waveguide along the first diameter.
A method comprising:
- forming a waveguide amplifier having a gain section that includes a coiled waveguide, the forming of the waveguide amplifier including forming an asymmetry in a refractive-index profile across the waveguide, wherein the forming of the waveguide amplifier includes forming an optical fiber having a straight fiber section and a coiled fiber section, and wherein coiling of the coiled section results in a reduction in the asymmetry of the coiled fiber section with respect to the straight fiber section.
A method comprising:
- forming a waveguide amplifier containing a coiled fiber gain section having a core, a transverse cross section of the coiled fiber gain section having a first diameter in a radial direction relative to a center of the coiled fiber gain section, and a second diameter in a direction perpendicular to the first diameter, the forming including fabricating the core to have a cross-section shape that is substantially symmetric relative to the first diameter and asymmetric relative to the second diameter, such that the core is ovoid in shape.
An apparatus comprising:
- a micro-structured waveguide amplifier having a coiled waveguide gain section, wherein the waveguide has a first diameter of a cross section of the waveguide and a second diameter of the cross section of the waveguide that is perpendicular to the first diameter, wherein the cross section of the waveguide is perpendicular to an axis of optical propagation in the waveguide, in which a refractive-index profile across the first diameter of the waveguide as fabricated is asymmetric.
An apparatus comprising:
- a micro-structured waveguide amplifier having a coiled waveguide gain section in which a refractive-index profile across a waveguide as fabricated is asymmetric, wherein the waveguide amplifier includes an optical fiber having a straight fiber section and a coiled fiber section, and wherein coiling of the coiled section results in a reduction in the asymmetry of the coiled fiber section with respect to the straight fiber section.
Dependencies are inferred from the claim text.