Abstract: An all-glass cladding mode stripper comprises a plurality of high refractive index, small diameter glass beads disposed along an exposed portion of the inner cladding region of an optical fiber. The unwanted low NA signal light (as well as any other type of stray light) propagating within the cladding layer is removed by refracting into the adjacent beads, where this captured light then scatters away from the optical fiber.

Abstract: An optical gain fiber for use in high power (e.g., greater than 500 W pump power) is proposed that is configured to exhibit a minimum bend radius such that the bend loss for the propagating LP01 mode is greater than about 0.03 dB/m. It has been discovered that this bend radius criteria, which is less stringent than that typically suggested in the art (e.g., bend loss less than about 0.03 dB/m), meets the modal stability requirements at high power operation, since the increase in operating temperature of the fiber laser or amplifier has been found to somewhat relax the bend radius requirement (which was heretofore only measured at “room temperature”, not “operating temperature”). Modal stability is defined in terms of a reduced presence of unwanted higher-order modes (such as the LP11 mode) in the amplified output signal.

Abstract: An all-glass cladding mode stripper comprises a plurality of high refractive index, small diameter glass beads disposed along an exposed portion of the inner cladding region of an optical fiber. The unwanted low NA signal light (as well as any other type of stray light) propagating within the cladding layer is removed by refracting into the adjacent beads, where this captured light then scatters away from the optical fiber.

Abstract: An optical gain fiber for use in high power (e.g., greater than 500 W pump power) is proposed that is configured to exhibit a minimum bend radius such that the bend loss for the propagating LP01 mode is greater than about 0.03 dB/m. It has been discovered that this bend radius criteria, which is less stringent, than that typically suggested in the art (e.g., bend loss less than about 0.03 dB/m), meets the modal stability requirements at high power operation, since the increase in operating temperature of the fiber laser or amplifier has been found to somewhat relax the bend radius requirement (which was heretofore only measured at “room temperature”, not “operating temperature”). Modal stability is defined in terms of a reduced presence of unwanted higher-order modes (such as the LP11 mode) in the amplified output signal.

Abstract: A high efficiency optical combiner minimizes core region distortions in the area where fusion splicing between an input tapered fiber bundle (or any other type of “cladding-less” input fiber) and output fiber are joined. The thickness of the output fiber's glass cladding layer in the splice region is reduced (if not removed altogether) so that a core-to-core splice is formed and any necked-down region where the glass flows to join the core regions (while also joining the outer diameters) is essentially eliminated. The reduction of distortions in the core region of the splice improves the transmission efficiency between an input tapered fiber bundle and output fiber, reaching a level of about 99%. This high efficiency optical combiner is particularly well-suited for applications where a number of pump sources are combined and applied as an input to a fiber laser or amplifier.

Abstract: A high efficiency optical combiner minimizes core region distortions in the area where fusion splicing between an input tapered fiber bundle (or any other type of “cladding-less” input fiber) and output fiber are joined. The thickness of the output fiber's glass cladding layer in the splice region is reduced (if not removed altogether) so that a core-to-core splice is formed and any necked-down region where the glass flows to join the core regions (while also joining the outer diameters) is essentially eliminated. The reduction of distortions in the core region of the splice improves the transmission efficiency between an input tapered fiber bundle and output fiber, reaching a level of about 99%. This high efficiency optical combiner is particularly well-suited for applications where a number of pump sources are combined and applied as an input to a fiber laser or amplifier.

Abstract: A light generation and amplification system includes a length of laser-active filter fiber having a refractive index profile that suppresses unwanted Stokes orders at wavelengths longer than a target wavelength and that has normal dispersion over its operating wavelength. A nested series of reflectors is provided at the fiber's input and output ends, and are configured to provide a nested series of Raman cavities, separated in wavelength by approximately the respective Stokes shifts. The first cavity in the series is a combined cavity that provides laser oscillation due to a combination of ionic gain and feedback at a selected first wavelength and that provides Raman gain to light at the first Stokes shift of the first wavelength when light at the first wavelength has an energy exceeding a Raman scattering threshold. The Raman cavities provide a stepwise transition between the first wavelength and the target wavelength.

Abstract: A light generation and amplification system includes a length of laser-active filter fiber having a refractive index profile that suppresses unwanted Stokes orders at wavelengths longer than a target wavelength and that has normal dispersion over its operating wavelength. A nested series of reflectors is provided at the fiber's input and output ends, and are configured to provide a nested series of Raman cavities, separated in wavelength by approximately the respective Stokes shifts. The first cavity in the series is a combined cavity that provides laser oscillation due to a combination of ionic gain and feedback at a selected first wavelength and that provides Raman gain to light at the first Stokes shift of the first wavelength when light at the first wavelength has an energy exceeding a Raman scattering threshold. The Raman cavities provide a stepwise transition between the first wavelength and the target wavelength.

Abstract: The present disclosure provides an approach to more efficiently amplify signals by matching either the gain materials or the pump profile with the signal profile for a higher-order mode (HOM) signal. By doing so, more efficient energy extraction is achieved.