Nufern

Nufem

Upendra H Manyam

Kanishka Tankala

Nils Jacobson

Julia A Farroni

Adrian Carter

Martin Seifert

Jaroslaw Abramczyk

Bryce Neilson Samson

Douglas Guertin

Mansoor Alam

Michael O'Connor

Optical apparatus () for providing light having a selected linear polarization having a polarization ratio, the apparatus () comprising a length of optical fiber () comprising a rare earth for providing light having a first wavelength responsive to receiving pump light having a second wavelength that is different than said first wavelength, wherein if the length of optical fiber () were placed in a first position between the length of fiber () is substantially linearly oriented () the fiber () could propagate at the first wavelength a fundamental mode and a plurality of higher order modes and the apparatus () could provide light having a first polarization ratio for the selected linear polarization and an Mparameter, and wherein the length of fiber () is positioned in a second position that increases the bend loss of the fiber relative to the first position such that, responsive to the increased bend loss, the apparatus () can provide light having a reduced Mparameter as well as a second polarization ratio for the selected polarization that is increased relative to the first polarization ratio, the increase being at least 6 dB greater than the first polarization ratio, and wherein when the length of fiber () is in the second position the apparatus () can provide a slope efficiency that is at least 50% of the ratio of the second wavelength to the first wavelength.

Method and apparatus for providing light having a selected polarization with an optical fiber

A fiber optic article can comprise a core, an inner region disposed about the core and a cladding disposed about the inner region. The index of refraction of the cladding can be less than that of the inner region, and the index of refraction of the inner region can be less than that of the core. The fiber can include a second cladding disposed about the cladding, where the second cladding has an index of refraction that is less than the index of refraction of the cladding. The inner region can have a non circular outer perimeter that includes at least one inwardly oriented section. The article can be elongate along a longitudinal axis and can include at least one longitudinally extending region, such as a stress inducing region, for providing birefringence and the inwardly oriented region can face the longitudinally extending region. The fiber optic article can include active material for providing light responsive to the article receiving pump light, such as, for example, one or more rare earths. The rare earths can include erbium and ytterbium.

Fiber optic article with inner region

An optical fiber comprising a multimode glass core having a diameter of at least 250 microns and an index of refraction and a polymer cladding having a thickness and contactingly surrounding a glass portion of the fiber so as to define an interface between the glass portion and the polymer cladding. The polymer cladding can have a first index of refraction that is less than the index of refraction. The fiber can comprise a density of less than 0.25 non-conforming regions having a diameter of 25 microns or greater per millimeter of length along the fiber, where each of the non-conforming regions is a region visible to the human eye under an optical microscope and having at least a portion thereof within a selected distance of the interface. The selected distance can be less than or equal to the thickness of the polymer cladding. The optical microscope can have a total magnification of about 200. The polymer cladding can be applied to at least a part of the optical fiber in at least a class 1000 environment. Methods of using optical fibers, including receiving with an optical fiber optical energy from a source and guiding the optical energy with the optical fiber, wherein the optical energy comprises at least one of 1) pulses each comprising a peak power of at least 10 kW, 2) an average power of at least 50 Watts, or 3) an average power density of at least 2.9 kW/cm.

Optical fiber having reduced defect density

An optical fiber coupler can include at least a first input optical fiber and an output optical fiber, where the first input optical fiber can comprise an antiguiding core, a first cladding disposed about the antiguiding core and a second cladding disposed about the first cladding so as to tend to confine light to said first cladding. The output fiber can comprise a guiding core, a first cladding disposed about the guiding core and a second cladding disposed about the first cladding of the output fiber for tending to confine light to the first cladding of the output fiber. Optical fibers are also disclosed, as are methods.

Fiber optic coupler, optical fiber useful with the coupler and/or a pump light source, and methods of coupling light

An optical fiber can include a glass core that is multimode at a selected wavelength and that comprises an index of refraction and a diameter D, a glass cladding disposed about said glass core, said glass cladding comprising an outer diameter Dand a first index of refraction that is less than said index of refraction of said core, and a second cladding disposed about said glass cladding, said second cladding comprising an optically cured polymer, said polymer comprising an index of refraction that is less than said first index of refraction. In certain embodiments, the fiber can include various other features. For example, [D/D]can be no greater than 1.5; the polymer can have a modulus of no greater than 100 MPa; the core can include means for affecting the power distribution amongst modes propagated by the core, such as by having a non circular outer perimeter; the core can support at least 100 modes at the selected wavelength; Dcan be at least 250 microns; the fiber can include a region disposed about the second cladding, and the region can comprise a polymer comprising an index of refraction that is greater than the index of refraction of said core. The fiber can be used, for example, for delivering light having the selected wavelength to or from a work object.

Optical fiber for delivering optical energy to or from a work object

An optical fiber for the transmission of electromagnetic energy, where the fiber can have increased input power threshold for the onset of Stimulated Brillouin Scattering (SBS). The fiber can comprise a core and a cladding disposed about the core. The core can have a distribution of velocities for an acoustic wave associated with SBS, where the distribution of propagation velocities of the core for the acoustic wave is at least one of a) azimuthally asymmetric or b) non-constant in an azimuthal plane and longitudinally asymmetric. The fiber can be longitudinally asymmetric wherein the core includes a first portion having a propagation velocity for the acoustic wave that is substantially the same throughout interposed between longitudinally spaced portions each having a propagation velocity different than that of said first portion. Methods, such as, for example, methods for fabricating and/or using a fiber having an increased threshold input power for the onset of SBS, are also disclosed.

Optical fiber with suppressed stimulated Brillouin scattering and method for making such a fiber

A polarization maintaining optical fiber has a core extending along a longitudinal axis, where the core includes a rare earth and a first index of refraction. A cladding is disposed about the core and has a first thermal coefficient of expansion (TCE) and a second index of refraction that is less than the first index of refraction. The fiber can include a pair of longitudinally extending members, and each of the members can have a TCE that is different than the first TCE of the cladding. The pair can be spaced apart by a distance d. A second cladding can be disposed about the first cladding, and the second cladding can have a third index of refraction that is less than the second index of refraction. The fiber can have a fundamental mode having a mode field diameter (MFD). The core can be a multimode core having a diameter dthat is greater than or equal to 15 microns, the numerical aperture of the core relative to the first cladding can be less than or equal to 0.12, the ratio d/MFD can be greater than 3, and the fiber can provide a beat length of less than 3 mm, where the beat length is measured at a wavelength of 633 nm.

Multimode polarization maintaining double clad fiber

An optical fiber having a length can include a core and at least one cladding disposed about the core, where the one cladding can comprise at least first volumetric regions having a first refractive index nand second volumetric regions having a second refractive index n, different from n, and the first and second volumetric regions in any cross-section taken through the fiber can be randomly intermingled with one another, where the random intermingling of the first and second volumetric regions changes with changes in the location of the cross-section along the length of the fiber.

Optical fiber with micro-structured cladding

A fiber optic article, such as an optical fiber or an optical preform, can include a core comprising a concentration of erbium, a concentration of fluorine and a concentration of ytterbium for sensitizing the erbium by absorbing pump light and transferring energy to the erbium. The erbium can provide light having a second wavelength different than the wavelength of the pump light. The article can also include a concentration of phosphorus. The fiber optic article can include a cladding disposed about the core, where the cladding has an index of refraction that is less than the index of refraction of the core, and a second cladding disposed about the first cladding, where the second cladding includes an index of refraction than is less than the index of refraction of the cladding. The fiber optic article can be elongate along a longitudinal axis and can include a longitudinally extending region for providing birefringence.

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Weatogue, CT, United States of America

Upendra H Manyam