Abstract: 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.

Abstract: 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.

Abstract: 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 Dcore, a glass cladding disposed about said glass core, said glass cladding comprising an outer diameter Dcladding and 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, [Dcladding/Dcore]2 can be no greater than 1.