Nufern

Nufem

Kanishka Tankala

Adrian Carter

Nils Jacobson

Upendra H Manyam

Julia A Farroni

Kevin Farley

Jaroslaw Abramczyk

Clemence Jollivet

Martin Seifert

Michael Conroy

Douglas Guertin

Bryce Neilson Samson

Imtiaz Majid

Chih-Hao Wang

Peyman Ahmadi

John Edgecumbe

Mansoor Alam

Eric Lim

The present disclosure relates more to mode mixing optical fibers useful, for example in providing optical fiber laser outputs having a desired beam product parameter and beam profile. In one aspect, the disclosure provides a mode mixing optical fiber for delivering optical radiation having a wavelength, the mode mixing optical fiber having an input end, an output end, a centerline and a refractive index profile, the mode mixing optical fiber comprising: an innermost core, the innermost core having a refractive index profile; and a cladding disposed about the innermost core, wherein the mode mixing optical fiber has at least five modes at the wavelength, and wherein the mode mixing optical fiber is configured to distribute a fraction of the light input at its input end from its lower-order modes to its higher-order modes.

Mode mixing optical fibers and methods and systems using the same

The present disclosure relates to systems and methods for reducing thermal effects in double-clad clad optical fiber amplifying systems via control of the pump absorption. One optical fiber amplifying system for reducing thermal effects includes one or more first optical pump sources, each configured to output radiation of a pump wavelength, a bridge optical fiber, having an input configured to receive the radiation of the pump wavelength output by the one or more first optical pump sources and an output, and an active optical fiber that has a first end substantially directly coupled to the output of the bridge optical fiber and a second end. The active optical fiber is configured to amplify radiation of the first active wavelength when pumped with radiation of the pump wavelength.

Optical amplifying systems and methods

The present disclosure relates more to mode mixing optical fibers useful, for example in providing optical fiber laser outputs having a desired beam product parameter and beam profile. In one aspect, the disclosure provides a mode mixing optical fiber that includes a core having a refractive index profile; and a cladding disposed about the core. The core of the mode mixing optical fiber supports at least two (e.g., at least five) guided modes at the wavelength. The mode mixing optical fiber is configured to substantially distribute optical radiation having the wavelength propagating therein (e.g., input at its input end or generated or amplified within the core) among a plurality of the guided modes (e.g., to distribute a substantial fraction of the optical radiation having the wavelength propagating therein from its lower-order guided modes to its higher-order guided modes).

An optical fiber preform, and method for fabricating, having a first core, a second core spaced from the first core and first and second regions, the first region having an outer perimeter having a first substantially straight length and the second region having an outer perimeter having a second substantially straight length facing the first straight length. One of the regions can comprise the first core and the other comprises the second core. The preform can be drawn with rotation to provide a fiber wherein a first core of the fiber is multimode at a selected wavelength of operation and a second core of the fiber is spaced from and winds around the first core and has a selected longitudinal pitch. The second core of the fiber can couple to a higher order mode of the first core and increase the attenuation thereof relative to the fundamental mode of the first core.

Optical fiber article for handling higher power and method of fabricating or using

The present invention relates generally to optical waveguides for the transmission of electromagnetic energy. The present invention relates more particularly to optical couplers for coupling optical fibers, and methods for making them. One aspect of the present invention is an optical coupler for use with a polarization-maintaining input optical fiber and a polarization-maintaining output optical fiber. The coupler includes: a tube having a wide end, a narrow end having an end face, and a taper therebetween; a polarization-maintaining feed-through optical fiber having a first end having an end face and a second end, the polarization-maintaining feed-through optical fiber being disposed within the tube from the wide end to the narrow end, at least the narrow end of the tube being fused around a first length of the polarization-maintaining feed-through optical fiber including the first end of the polarization-maintaining feed-through optical fiber to form a coupler end face comprising the end face of the tube and the end face of the first end of the polarization-maintaining feed-through optical fiber. In one aspect of the invention, the polarization-maintaining feed-through optical fiber has an outer diameter no greater than about 200 &#x3bc;m in the region in which the tube is fused around it. In another aspect of the invention, the polarization-maintaining feed-through optical fiber has an outer diameter at the coupler end face no greater than about 75% of the diameter of the polarization-maintaining input optical fiber.

Optical couplers and methods for making same

The present invention relates to optical fibers useful for the transmission of electromagnetic energy at such high levels of power that stimulated Brillouin scattering (SBS) may be of importance. One aspect of the present invention is an optical fiber for the propagation of optical radiation having an optical wavelength, the optical fiber and optical wavelength having an SBS acoustic wavelength associated therewith, the optical fiber comprising a core having a geometrical center and an outer perimeter; and a cladding surrounding the core; wherein the core is rare earth doped and substantially free of germanium, the optical fiber has a refractive index profile such that the core is guiding for optical radiation having the optical wavelength, and the optical fiber has an acoustic index profile such that the core is antiguiding for an acoustic wave having the SBS acoustic wavelength.

Optical fiber with suppressed stimulated brillouin scattering

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 comprises a photosensitive core that includes a concentration of a first material that increases the refractive index of the core and a concentration of a second material that is other than boron and that reduces the refractive index of the core. A cladding is disposed about the core for tending to confine light to the core. The fiber also includes at least one longitudinally extending region having a thermal coefficient of expansion that is different from the thermal coefficient of expansion of the cladding. In another embodiment, the core includes a concentration of germanium and a concentration of boron. Also disclosed is a polarization-maintaining double-clad (PM DC) fiber comprising one or both of at least one circular axially extending stress inducing region(s) and an inner cladding comprising a circular outer perimeter. Fibers according to the invention can include a rare earth dopant for emitting light of a selected wavelength responsive to being pumped by pump light of a pump wavelength that is different than the selected wavelength.

Optical fiber

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.

Growing community of inventors

South Windsor, CT, United States of America

Kanishka Tankala