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: 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: 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: 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: 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: 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: An optical apparatus includes one or more pump sources situated to provide laser pump light, and a gain fiber optically coupled to the one or more pump sources, the gain fiber including an actively doped core situated to produce an output beam, an inner cladding and outer cladding surrounding the doped core and situated to propagate pump light, and a polymer cladding surrounding the outer cladding and situated to guide a selected portion of the pump light coupled into the inner and outer claddings of the gain fiber. Methods of pumping a fiber sources include generating pump light from one or more pump sources, coupling the pump light into a glass inner cladding and a glass outer cladding of a gain fiber of the fiber source such that a portion of the pump light is guided by a polymer cladding surrounding the glass outer cladding, and generating a single-mode output beam from the gain fiber.

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: 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: An optical apparatus includes one or more pump sources situated to provide laser pump light, and a gain fiber optically coupled to the one or more pump sources, the gain fiber including an actively doped core situated to produce an output beam, an inner cladding and outer cladding surrounding the doped core and situated to propagate pump light, and a polymer cladding surrounding the outer cladding and situated to guide a selected portion of the pump light coupled into the inner and outer claddings of the gain fiber. Methods of pumping a fiber sources include generating pump light from one or more pump sources, coupling the pump light into a glass inner cladding and a glass outer cladding of a gain fiber of the fiber source such that a portion of the pump light is guided by a polymer cladding surrounding the glass outer cladding, and generating a single-mode output beam from the gain fiber.

Abstract: An optical beam delivery device is formed of optical fibers configured for beam divergence or mode coupling control. An incident optical beam propagates through a first length of fiber, which is coupled to a second length of fiber and has a first refractive index profile (RIP). The first RIP enables, in response to an applied perturbation, modification of the beam characteristics of the incident optical beam to form an adjusted optical beam having modified beam characteristics relative to beam characteristics of the incident optical beam. The second length of fiber is formed with one or more confinement regions defining a second RIP and arranged to confine at least a portion of the adjusted optical beam. The second and first lengths of fiber are tapered in the direction of light beam propagation to control output beam divergence or susceptibility to beam mode coupling in the first length of fiber, respectively.

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: An optical power control system includes a laser source to provide an optical beam, a variable beam characteristics (VBC) fiber, and a controller operatively coupled to the VBC fiber and configured to control, in response to information indicating change in optical power of the optical beam, different states of perturbation so as to control optical power density.

Abstract: Disclosed are an optical beam delivery device, systems, and methods for sequentially adjusting, with respect to members of a set of confinement regions, a propagation path for establishing a controllable, temporally apparent intensity distribution. The disclosed techniques entail applying to a variable beam characteristics (VBC) fiber different states perturbation to change the propagation path and the members of the set of confinement regions through which a confined portion of an adjusted optical beam propagates, thereby establishing at an output end of the VBC fiber the controllable, temporally apparent intensity distribution.

Abstract: An all-fiber optical beam switch mechanism includes a first length of fiber through which an incident optical beam having beam characteristics propagates along a first propagation path and which has a first refractive index profile (RIP). The first RIP enables, in response to an applied perturbation, modification of the optical beam to form an adjusted optical beam that is movable to propagate along a second propagation path. A second length of fiber is coupled to the first length of fiber and formed with multiple spaced-apart, non-coaxial confinement cores. A selected state of applied perturbation moves the second propagation path of the adjusted optical beam to a position of a selected corresponding one of the multiple confinement cores to confine and thereby direct the adjusted optical beam to a corresponding beam output location at the output of the second length of fiber.

Abstract: An optical beam delivery device is configured to generate, from an optical beam, selectable intensity profiles. The device has a first length of fiber having a first refractive index profile (RIP), and a second length of fiber having second RIP that is different from the first RIP. The second length of fiber includes coaxial confinement regions arranged to confine at least a portion of an adjusted optical beam. The confined portion corresponds to an intensity distribution of different intensity distributions. The intensity distribution is established by a corresponding state of different states of perturbation that is applied to the device such that the confined portion is configured to provide, at an output of the second length of fiber, a selected intensity profile of the selectable intensity profiles.

Abstract: An optical beam delivery device formed of optical fibers that are configured to produce an output exhibiting an intensity distribution profile having non-zero ellipticity includes a first length of fiber through which an incident optical beam having beam characteristics propagates and which has a first refractive index profile (RIP). The first RIP enables, in response to an applied perturbation, modification of the beam characteristics of the optical beam to form an adjusted beam having modified beam characteristics relative to the beam characteristics of the optical beam. A second length of fiber is coupled to the first length of fiber and formed with a set of one or more confinement regions that define a second RIP and confine at least a portion of the adjusted beam to generate, at an output of the second length of fiber, an intensity distribution profile having non-zero ellipticity.

Abstract: An optical beam delivery device establishes, from an optical beam, an optical trap that is moveable to different optical trap locations. The device has a first length of fiber through which the optical beam propagates along a propagation path and which has a first refractive index profile (RIP) enabling modification of the propagation path to form an adjusted optical beam movable to propagate along different propagation paths in response to different states of applied perturbation. The device also has a second length of fiber coupled to the first length of fiber and having confinement cores defining a second RIP. The confinement cores occupy different positions in, and correspond to the different optical trap locations at an output of, the second length of fiber.

Abstract: An optical apparatus includes one or more pump sources situated to provide laser pump light, and a gain fiber optically coupled to the one or more pump sources, the gain fiber including an actively doped core situated to produce an output beam, an inner cladding and outer cladding surrounding the doped core and situated to propagate pump light, and a polymer cladding surrounding the outer cladding and situated to guide a selected portion of the pump light coupled into the inner and outer claddings of the gain fiber. Methods of pumping a fiber sources include generating pump light from one or more pump sources, coupling the pump light into a glass inner cladding and a glass outer cladding of a gain fiber of the fiber source such that a portion of the pump light is guided by a polymer cladding surrounding the glass outer cladding, and generating a single-mode output beam from the gain fiber.