Abstract: In an example, a tandem pumped fiber amplifier may include a seed laser, a first section coupled to an output of the seed laser, and a second section coupled to an output of the first section. The first section may operate as an oscillator, and may receive pump light from one or more diode pumps, and may the first section may be arranged to convert the one or more diode pumps into a tandem pump. The second section may operate as a power amplifier, and may include a length of a single or plural active core fiber. The tandem pumped fiber amplifier may be arranged to mitigate spectral broadening related to four-wave mixing.

Abstract: In an example, a tandem pumped fiber amplifier may include a seed laser, one or more diode pumps, and a single or plural active core fiber. The single or plural active core fiber may include a first section to operate as an oscillator and a second different section to operate as a power amplifier. The one or more diode pumps may be optically coupled to the first section of the single or plural active core fiber, and the seed laser may be optically coupled to the single active core or an innermost core of the plural active core fiber.

Abstract: Large mode area optical fibers include cores that are selected to be smaller than a core size associated with a minimum mode field diameter of a lowest order mode. Cross-sectional shape of such cores can be circular or annular, and a plurality of such cores can be used. Gain regions can be provided in cores or claddings, and selected to produce a selected state of polarization.

Abstract: Methods include directing a laser beam to a target along a scan path at a variable scan velocity and adjusting a digital modulation during movement of the laser beam along the scan path and in relation to the variable scan velocity so as to provide a fluence at the target within a predetermined fluence range along the scan path. Some methods include adjusting a width of the laser beam with a zoom beam expander. Apparatus include a laser source situated to emit a laser beam, a 3D scanner situated to receive the laser beam and to direct the laser beam along a scan path in a scanning plane at the target, and a laser source digital modulator coupled to the laser source so as to produce a fluence at the scanning plane along the scan path that is in a predetermined fluence range as the laser beam scan speed changes along the scan path.

Abstract: Systems and methods for reducing the deleterious effects of specular reflections (e.g., glint) on active illumination systems are disclosed. An example system includes an illuminator or light source configured to illuminate a scene with electromagnetic radiation having a defined polarization orientation. The system also includes a receiver for receiving portions of the electromagnetic radiation reflected or scatter from the scene. Included in the receiver is a polarizer having a polarization axis crossed with the polarization orientation of the emitted electromagnetic radiation. By crossing the polarizer with the polarization of the emitted electromagnetic radiation, the polarizer may filter out glint or specular reflections in the electromagnetic radiation returned from the scene.

Abstract: A laser diode package, comprising a housing having a metal base portion, an integrated heat spreader formed within the base, the integrated heat spreader comprising a first phase-change material (PCM) and configured to dissipate heat via phase-change cooling. A heat source may be disposed on a top surface of the base, the heat source may be thermally coupled to the integrated heat spreader so as to dissipate heat away from the heat source via phase-change cooling.

Abstract: Signal combined optical fiber devices, systems, and methods for reducing signal spectrum pumping of Raman spectrum. Power of a Raman component in an output of a signal combined fiber laser system may be reduced by diversifying peak signal wavelengths across a plurality of signal generation and/or amplification modules that are input into a signal combiner. In some examples, fiber laser oscillators that are to have their output signals combined to reach a desired cumulative system output power are tuned to output signal bands of sufficiently different wavelengths that signal from separate ones of the oscillators do not collectively pump a single Raman band. With the combined signal component comprising different peak signal wavelengths, the Raman component of combined output may have multiple peak wavelengths and significantly lower power than in systems where signals of substantially the same signal peak wavelength are combined.

Abstract: Spliced multi-clad optical fibers with a cladding light stripper (CLS) encapsulating the splice. The splice may facilitate conversion between two optical fibers having different architectures, such as different core and/or cladding dimensions. The CLS may comprise a first length of fiber on a first side of the splice, and a second length of fiber on a second side of the splice, encapsulating the splice within the lengths of the CLS. The splice may abut one or more of the lengths of the CLS, or may be separated from one or more lengths of the CLS by an intermediate length of a first and/or second fiber joined by the splice.

Abstract: Optical fiber devices, systems, and methods for separating Raman spectrum from signal spectrum. Once separated, the Raman spectrum may be suppressed (e.g., as a result of a reduction in gain from the signal spectrum, and/or through dissipation of the Raman spectrum energy), while the signal spectrum may be propagated in one or more guided modes of a fiber system. In some embodiments, a fiber system may include a chirped fiber Bragg grating (CFBG) or a long period fiber grating (LPFG), each configured to couple a core propagation mode into a cladding propagation mode with an efficiency that is higher for Raman spectrum than for signal spectrum. A fiber system further may include a cladding light stripper (CLS) configured to preferentially remove cladding modes containing the Raman component.

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: 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: 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: A laser diode, comprising a transverse waveguide comprising an active layer between an n-type semiconductor layer and a p-type semiconductor layer wherein the transverse waveguide is bounded by a lower index n-cladding layer on an n-side of the transverse waveguide and a lower index p-cladding layer on a p-side of the transverse waveguide a cavity that is orthogonal to the transverse waveguide, wherein the cavity is bounded in a longitudinal direction at a first end by a high reflector (HR) facet and at a second end by a partial reflector (PR) facet, and a first contact layer electrically coupled to the waveguide and configured to vary an amount of current injected into the waveguide in the longitudinal direction so as to inject more current near the HR facet than at the PR facet.

Abstract: Systems and methods for reducing or eliminating undesired effects of retro-reflections in imaging are disclosed. A system for reducing the undesired effects of retro-reflections may include an illuminator and an optical receiver. The illuminator is configured to emit an illumination signal for illuminating a scene. The optical receiver is configured to receive returned portions of the illumination signal scattered or reflected from the scene. Return signals from retroreflectors present in the scene may oversaturate or otherwise negatively affect sensors in the optical receiver. To limit return signals from retroreflectors that may be present in the scene, the illuminator and optical receiver are physically separated from each other by an offset distance that limits or prevents retro-reflections from the retroreflectors from being received by the optical receiver.

Abstract: Optical fiber devices, systems, and methods for separating Raman spectrum from signal spectrum Raman spectrum may be suppressed as a result of a reduction in gain and/or through dissipation while the signal spectrum may Raman Components In be propagated in one or more guided modes of a fiber system. A fiber system may Length include a propagation mode coupler to couple a first guided mode into a second guided mode with an efficiency that varies as a function of wavelength of the propagated light. Mode coupling efficiency may be higher for Raman spectrum, and lower for signal spectrum so that Raman spectrum associated with a fundamental mode is preferentially coupled into a higher-order mode. A fiber system may include a mode filter operable to discriminate between first and second guided modes. Within the filter, guiding of the first mode may be superior to that of the second mode with Raman spectrum preferentially rejected.

Abstract: A laser system capable of producing a stable and accurate high-power output beam from one or more input beams of corresponding laser sources comprises one or more optical elements configured to receive the input beams wherein at least one of said one or more optical elements is made of high purity fused silica.

Abstract: Apparatuses, systems and methods for modulating returned light for acquisition of 3D data from a scene are described. A 3D imaging system includes a Fabry-Perot cavity having a first partially-reflective surface for receiving incident light and a second partially-reflective surface from which light exits. An electro-optic material is located within the Fabry-Perot cavity between the first and second partially-reflective surfaces. Transparent longitudinal electrodes or transverse electrodes produce an electric field within the electro-optic material. A voltage driver is configured to modulate, as a function of time, the electric field within the electro-optic material so that the incident light passing through the electro-optic material is modulated according to a modulation waveform. A light sensor receives modulated light that exits the second partially-reflective surface of the Fabry-Perot cavity and converts the light into electronic signals.

Abstract: A burst logging system logs and transmits to a local or remote computing system event data related to errors in and or potential failures of laser system components. The system further provides for capturing data at different rates from different sensors, synchronization of data capture associated with system events and the possibility for aggregation of data from multiple systems, which can in turn be leveraged to predict and or remediate future system events.

Abstract: In an example, a tandem pumped fiber amplifier may include a seed laser, one or more diode pumps, and a single or plural active core fiber. The single or plural active core fiber may include a first section to operate as an oscillator and a second different section to operate as a power amplifier. The one or more diode pumps may be optically coupled to the first section of the single or plural active core fiber, and the seed laser may be optically coupled to the single active core or an innermost core of the plural active core fiber.

Abstract: An example apparatus includes an optical fiber including a core and cladding, the core being situated to propagate an optical beam along a propagation axis associated with the core, and at least one fiber Bragg grating (FBG) situated in the core of the optical fiber, the fiber Bragg grating including a plurality of periodically spaced grating portions situated with respect to the propagation axis so that light associated with Raman scattering is directed out of the core so as to reduce the generation of optical gain associated with stimulated Raman scattering (SRS).