Abstract: Disclosed are optical beam delivery devices and methods to produce, from a single-mode input beam having a fundamental mode and an M2 beam quality of about 1.5 or less, an output beam having an adjustable spatial intensity distribution that is adjustable between near Gaussian and ring-shaped profiles, the near Gaussian profile corresponding to an M2 beam quality of about 1.5 or less. A first length of optical fiber is for adjusting the single-mode input beam to generate an adjustable beam based on controllable perturbation applied to the first length of optical fiber. A second length of optical fiber is for coupling the adjustable beam into one or both a central core confinement region and an annular higher-index confinement region. The second length of optical fiber is configured to provide at its output the output beam having the adjustable spatial intensity distribution.

Abstract: Beam combining optical systems include a fiber beam combiner having multiple inputs to which output fibers of laser diode sources are spliced. Cladding light stripping regions are situated at the splices and include exposed portions of fiber claddings that are at least partially encapsulated with an optical adhesive or a polymer. A beam combiner fiber that is optically downstream of a laser source has an exposed cladding secured to a thermally conductive support with a polymer or other material that is index matched to the exposed cladding. This construction permits attenuation of cladding light propagating toward a beam combiner from a splice.

Abstract: Disclosed are optical beam delivery devices and methods to modify an angular intensity distribution of an input beam so that it is converted to an output beam having an adjustable near-field transverse spatial intensity distribution. In some embodiments, adjustment of the angular intensity distribution is achieved by increasing an angular offset in response to controllable perturbation. In some other embodiments, adjustment of the angular intensity distribution is achieved by increasing an angular width (divergence) in response to controllable perturbation.

Abstract: Optical fiber devices, systems, and methods for coupling Raman spectrum out of an optical fiber selectively over a signal spectrum, which may be propagated in one or more guided modes of a fiber system. A fiber system may include a chirped fiber Bragg grating (CFBG) or a long period fiber grating (LPFG), each to unguide Raman light propagating in a core propagation mode of a fiber completely out of the fiber (through any surrounding cladding layer(s)) selectively over signal spectrum which is to remain in a guided mode of the fiber.

Abstract: Disclosed is an optical fiber-based divergence-limiting device for limiting divergence from a first maximum divergence of input light to a second maximum divergence of output light, in which the second maximum divergence is less than the first maximum divergence.

Abstract: Fiber laser devices, systems, and methods for reducing Raman spectrum in emissions from a resonant cavity. A fiber laser oscillator that is to generate an optical beam may include a Raman reflecting output coupler that strongly reflects a Raman component pumped within the resonant cavity, and partially reflects a signal component to sustain the oscillator and emit a signal that has a reduced Raman component. A Raman filtering output coupler may comprise a superstructure fiber grating, and such a grating may be chirped or otherwise designed to have a desired bandwidth.

Abstract: A method of generating adjustable composite beam shapes in response to controllable perturbation includes receiving, via inputs of multiple input fibers, different laser beams, combining the outputs from the multiple input fibers into a divergence-preserving fiber that preserves a combined divergence distribution of the intermediate beams; and converting at an output lens the combined divergence distribution to an output transverse spatial intensity distribution defining a composite beam shape of an output beam. The output transverse spatial intensity distribution includes a superposition of individual channel output beams.

Abstract: A fused fiber combiner combines outputs from multiple, separately controllable input fibers. At least one of the input fibers includes a portion to vary a transverse spatial intensity distribution in response to controllable perturbation, a portion to convert position to angle, and a portion to preserve the divergence distribution. An output of the combiner is coupled to a divergence-preserving fiber, which preserves a combined divergence distribution guided by the divergence-preserving fiber. An output GRIN lens maps the combined divergence distribution to an output transverse spatial intensity distribution defining a composite beam shape of an output beam, the output transverse spatial intensity distribution representing a superposition of individual channel output beams.

Abstract: Apparatus include a first optical fiber including a core situated to propagate a signal beam at a signal wavelength and an unwanted stimulated Raman scattering (SRS) beam at an SRS wavelength associated with the signal wavelength, and a fiber Bragg grating (FBG) situated in a core of a second optical fiber optically coupled to the core of the first optical fiber, the FBG having a selected grating reflectivity associated with the SRS wavelength and being situated to reflect the SRS beam back along the core of the second optical fiber and to reduce a damage associated with propagation of the SRS beam to power sensitive laser system components optically coupled to the second optical fiber. Methods are also disclosed.

Abstract: A method of processing by controlling one or more beam characteristics of an optical beam may include: launching the optical beam into a first length of fiber having a first refractive-index profile (RIP); coupling the optical beam from the first length of fiber into a second length of fiber having a second RIP and one or more confinement regions; modifying the one or more beam characteristics of the optical beam in the first length of fiber, in the second length of fiber, or in the first and second lengths of fiber; confining the modified one or more beam characteristics of the optical beam within the one or more confinement regions of the second length of fiber; and/or generating an output beam, having the modified one or more beam characteristics of the optical beam, from the second length of fiber. The first RIP may differ from the second RIP.

Abstract: Disclosed herein are methods, apparatus, and systems for providing an optical beam delivery system, comprising an optical fiber including a first length of fiber comprising a first RIP formed to enable, at least in part, modification of one or more beam characteristics of an optical beam by a perturbation assembly arranged to modify the one or more beam characteristics, the perturbation assembly coupled to the first length of fiber or integral with the first length of fiber, or a combination thereof and a second length of fiber coupled to the first length of fiber and having a second RIP formed to preserve at least a portion of the one or more beam characteristics of the optical beam modified by the perturbation assembly within one or more first confinement regions.

Abstract: Fiber bending mechanisms vary beam characteristics by deflecting or bending one or more fibers, by urging portions of one or more fibers toward a fiber shaping surface having a selectable curvature, or by selecting a fiber length that is to be urged toward the fiber shaping surface. In some examples, a fiber is secured to a flexible plate to conform to a variable curvature of the flexible plate. In other examples, a variable length of a fiber is pulled or pushed toward a fiber shaping surface, and the length of the fiber or a curvature of the flexible plate provide modification of fiber beam characteristics.

Abstract: Some embodiments may include a fiber laser including two or more input fibers and an output fiber to deliver a beam to a workpiece, the fiber laser comprising. The fiber laser may include a combiner having ends and a length, wherein the combiner is arranged to release, from its length, a portion of back-reflected light received from the output fiber at an output end of the ends from the combiner, the combiner including: a capillary tube to enclose part of the two or more input fibers at an input end of the ends of the combiner, the capillary tube having ends and a length located between the ends of the capillary tube; and a cladding light stripper (CLS) defined by part of the length of the capillary tube, wherein the CLS provides the release of the portion of the back-reflected light. Other embodiments may be disclosed and/or claimed.

Abstract: Angularly homogenizing gradient index optical fiber having a refractive index profile that is non-quadratic to a degree sufficient to enhance precession of light as it is propagated through the fiber. Deviation from the quadratic may be limited to avoid profoundly changing the radial boundary within the fiber. Beam asymmetry, for example, associated with small aperture sources launched into a fiber off axis, may be made more symmetric as the beam is propagated through the homogenizing gradient index optical fiber. A refractive index profile may be manufactured to avoid a pure quadratic profile, or a fiber having a refractive index profile that is quadratic in only some orientations about the fiber axis may be twisted during draw to induce a refractive index profile path that enhances propagation precession.

Abstract: An apparatus includes an optical gain fiber having a core, a cladding surrounding the core, the core and cladding defining an optical gain fiber numerical aperture, and a multimode fiber having a core with a larger radius than a radius of the optical gain fiber core, a cladding surrounding the core, the core and cladding of the multimode fiber defining a multimode fiber stable numerical aperture that is larger than the optical gain fiber numerical aperture, the multimode fiber being optically coupled to the optical gain fiber so as to receive an optical beam propagating in the optical gain fiber and to stably propagate the received optical beam in the multimode fiber core with low optical loss associated with the optical coupling.

Abstract: Some embodiments may include a power monitor to measure power of laser light propagating in a core of an optical fiber; the power monitor to generate a sensor signal using an optical sensor having a light sensitive section with no line of sight to part of the optical fiber; wherein the sensor signal is derived from light emerging laterally from the part of the optical fiber. Other embodiments may be disclosed and/or claimed.

Abstract: Disclosed is an optical fiber-based divergence-limiting device for limiting divergence from a first maximum divergence of input light to a second maximum divergence of output light, in which the second maximum divergence is less than the first maximum divergence.

Abstract: Disclosed are embodiments for multi-band pumping of a doped fiber source. The doped fiber source has a first absorption band and a second absorption band that is different from the first absorption band. In some embodiments, a first laser pump generates a first pump power in a first pump band corresponding to the first absorption band that is generated. A second laser pump generates a second pump power in a second pump band corresponding to the second absorption band. The second pump band is different from the first pump band. The first and second pump power is simultaneously applied to the doped fiber source.

Abstract: Some embodiments may include a fiber laser including two or more input fibers and an output fiber to deliver a beam to a workpiece, the fiber laser comprising. The fiber laser may include a combiner having ends and a length, wherein the combiner is arranged to release, from its length, a portion of back-reflected light received from the output fiber at an output end of the ends from the combiner, the combiner including: a capillary tube to enclose part of the two or more input fibers at an input end of the ends of the combiner, the capillary tube having ends and a length located between the ends of the capillary tube; and a cladding light stripper (CLS) defined by part of the length of the capillary tube, wherein the CLS provides the release of the portion of the back-reflected light. Other embodiments may be disclosed and/or claimed.

Abstract: A method of processing by controlling one or more beam characteristics of an optical beam may include: launching the optical beam into a first length of fiber having a first refractive-index profile (RIP); coupling the optical beam from the first length of fiber into a second length of fiber having a second RIP and one or more confinement regions; modifying the one or more beam characteristics of the optical beam in the first length of fiber, in the second length of fiber, or in the first and second lengths of fiber; confining the modified one or more beam characteristics of the optical beam within the one or more confinement regions of the second length of fiber; and/or generating an output beam, having the modified one or more beam characteristics of the optical beam, from the second length of fiber. The first RIP may differ from the second RIP.