Abstract: A high-power Raman fiber laser includes: a seed laser; a plurality of pump lasers, each including a cladding and comprising of thulium-doped fiber laser (TDFL) and configured to operate in a 1935-2020 nm spectral window; a pump/seed combiner to combine outputs of the pump lasers and output of the seed laser and having a tapered portion including a cladding; and a Raman fiber amplifier having a core and a cladding surrounding the core, the seed laser is launched into the core, and pump laser output beams are launched into the cladding, to amplify the seed laser to produce an amplified output signal, and a brightness of the cladding of the Raman fiber amplifier is matched to a combined brightness of the plurality of pump lasers.

Abstract: A system includes at least one controller configured to determine an optical phase modulation pattern for suppression of stimulated Brillouin scattering (SBS) in a combined beam that emerges off a diffractive grating in a spectral beam combining (SBC) system and maximization of an output power of the combined beam. The system also includes multiple master oscillators configured to generate multiple beams in the SBC system. The system also includes multiple phase modulators configured to phase modulate the multiple beams according to the determined optical phase modulation pattern. The system also includes multiple fiber amplifier chains configured to receive the phase modulated beams and output the beams from the master oscillators to multiple delivery fibers for subsequent combining into the combined beam at the diffractive grating.

Abstract: Methods and apparatus for providing spectrally beam-combined fiber-based transmitters and/or receivers for laser communications, LiDAR, and similar devices. A transmitter can include a launch array configured to spatially position each output beam of pulsed lasers, a transform optical component to correct deflection of the output beams of the pulsed lasers from the launch array, and a dispersive optical element to combine beams from the transform optical element and generate a spectrally combined beam. A receiver can include spectral comb filters to spectrally discriminate multi-wavelength detected signals from background illumination.

Abstract: A system includes multiple first thulium-doped fiber lasers each configured to generate pumplight. The system also includes a second thulium-doped fiber laser configured to receive the pumplight from the first thulium-doped fiber lasers and a seed signal. The second thulium-doped fiber laser is also configured to amplify the seed signal using the pumplight. The first thulium-doped fiber lasers are configured to forward-pump the second thulium-doped fiber laser. The second thulium-doped fiber laser includes a fiber gain medium, where the fiber gain medium includes a core doped with thulium and a cladding. The fiber gain medium is longitudinally up-tapered such that a diameter of the core and a diameter of the cladding increase along at least a portion of a length of the fiber gain medium.

Abstract: A method includes generating, using a transmitter, an optical signal for each fiber incoherently combined in a fiber bundle. The method also includes transmitting the optical signal from each fiber as pulses at a target. The method further includes receiving, using a receiver array, the pulses of the optical signals and identifying one or more parameters of the target based on the pulses of the optical signals.

Abstract: A system includes multiple laser diode modules that are spatially separated and configured to generate multiple optical beams that propagate at angles relative to each other. The system also includes an optical element having at least one entrance surface and at least one exit surface. The optical element is configured to receive the optical beams at the at least one entrance surface and output each optical beam through the at least one exit surface such that the output optical beams are closely spaced, substantially the same size, and substantially parallel to each other at a common distance downstream from the optical element, and the optical beams all share a common downstream image plane.

Abstract: A system includes a signal seeder configured to generate a pulsed seed signal, where the signal seeder includes a master oscillator configured to generate an optical signal at a first wavelength. The system also includes a series of optical preamplifiers collectively configured to amplify the pulsed seed signal and generate an amplified signal. The system further includes a Raman fiber amplifier configured to amplify the amplified signal and generate a Raman-shifted amplified signal. The Raman fiber amplifier is configured to shift a wavelength of the amplified signal to a second wavelength different than the first wavelength during generation of the Raman-shifted amplified signal.

Abstract: An example optical system architecture includes a diode laser source having an optical fiber. The diode laser source is configured to generate an optical signal having a main mode and side longitudinal modes and to output the optical signal along an optical path. An optical filter is in the optical path. The optical filter is configured to receive at least part of the optical signal, to output the main mode along the optical path, and to suppress the side longitudinal modes at least in part. One or more optical amplifiers are in the optical path after the optical filter. The one or more optical amplifiers are configured to receive at least part of the main mode, to amplify the at least part of main mode, and to output an amplified version of the at least part of main mode along the optical path.

Abstract: A method includes generating, using a transmitter, an optical signal for each fiber incoherently combined in a fiber bundle. The method also includes transmitting the optical signal from each fiber as pulses at a target. The method further includes receiving, using a receiver array, the pulses of the optical signals and identifying one or more parameters of the target based on the pulses of the optical signals.

Abstract: Methods and apparatus for providing spectrally beam-combined fiber-based transmitters and/or receivers for laser communications, LiDAR, and similar devices. A transmitter can include a launch array configured to spatially position each output beam of pulsed lasers, a transform optical component to correct deflection of the output beams of the pulsed lasers from the launch array, and a dispersive optical element to combine beams from the transform optical element and generate a spectrally combined beam. A receiver can include spectral comb filters to spectrally discriminate multi-wavelength detected signals from background illumination.

Abstract: Methods and apparatus for optical beam steering including a laser to generate a beam having an optical frequency and an optical phase modulator (OPM) to impart a shift in the optical frequency of the beam from the laser. A dispersive optical element maps the shift in the optical frequency to a corresponding angle with respect to the dispersive optical element, which can comprise a diffraction grating.

Abstract: An example optical system architecture includes a diode laser source having an optical fiber. The diode laser source is configured to generate an optical signal having a main mode and side longitudinal modes and to output the optical signal along an optical path. An optical filter is in the optical path. The optical filter is configured to receive at least part of the optical signal, to output the main mode along the optical path, and to suppress the side longitudinal modes at least in part. One or more optical amplifiers are in the optical path after the optical filter. The one or more optical amplifiers are configured to receive at least part of the main mode, to amplify the at least part of main mode, and to output an amplified version of the at least part of main mode along the optical path.

Abstract: A system includes at least one controller configured to determine an optical phase modulation pattern for suppression of stimulated Brillouin scattering (SBS) in a combined beam that emerges off a diffractive grating in a spectral beam combining (SBC) system and maximization of an output power of the combined beam. The system also includes multiple master oscillators configured to generate multiple beams in the SBC system. The system also includes multiple phase modulators configured to phase modulate the multiple beams according to the determined optical phase modulation pattern. The system also includes multiple fiber amplifier chains configured to receive the phase modulated beams and output the beams from the master oscillators to multiple delivery fibers for subsequent combining into the combined beam at the diffractive grating.

Abstract: Spectral beam combining systems including a multi-element transform optic. In certain examples the multi-element transform optic includes a first cylindrical optical element having positive optical power in a first axis, a second optical element having negative optical power in the first axis, and a third toroidal optical element having positive optical power in the first axis and either positive or negative optical power in a second axis that is orthogonal to the first axis. The first and third optical elements are positioned on opposite sides of the second optical element and equidistant from the second optical element. The multi-element transform optic has an optical path length extending between a front focal plane and a back focal plane that is shorter than an effective focal length of the multi-element transform optic.

Abstract: A system includes a waveform generator configured to generate a pulsed laser beam at a first wavelength. The system also includes at least one splitter configured to split the laser beam into multiple beams at the first wavelength. The system also includes at least one wavelength shifter configured to shift at least one of the multiple beams to another wavelength. The system also includes at least one combiner configured to combine the multiple beams into a multi-wavelength beam in which multiple wavelengths are co-aligned and propagating parallel to each other. The system also includes at least one nonlinear crystal configured to receive the multi-wavelength beam and generate multiple co-propagating beams using nonlinear wavelength conversion.

Abstract: Spectral beam combining systems including a multi-element transform optic. In certain examples the multi-element transform optic includes a first cylindrical optical element having positive optical power in a first axis, a second optical element having negative optical power in the first axis, and a third toroidal optical element having positive optical power in the first axis and either positive or negative optical power in a second axis that is orthogonal to the first axis. The first and third optical elements are positioned on opposite sides of the second optical element and equidistant from the second optical element. The multi-element transform optic has an optical path length extending between a front focal plane and a back focal plane that is shorter than an effective focal length of the multi-element transform optic.

Abstract: A laser transmitter is provided that includes a seed signal generator, an amplitude modulator and a power amplifier. The seed signal generator is configured to generate a seed signal that has a continuous waveform. The amplitude modulator is configured to generate a flat-top pulse signal based on the seed signal. The power amplifier is configured to generate a laser output signal based on the flat-top pulse signal.

Abstract: A laser transmitter is provided that includes a seed signal generator, an amplitude modulator and a power amplifier. The seed signal generator is configured to generate a seed signal that has a continuous waveform. The amplitude modulator is configured to generate a flat-top pulse signal based on the seed signal. The power amplifier is configured to generate a laser output signal based on the flat-top pulse signal.

Abstract: A laser transmitter is provided that includes a seed signal generator, an amplitude modulator and a power amplifier. The seed signal generator is configured to generate a seed signal that has a continuous waveform. The amplitude modulator is configured to generate a flat-top pulse signal based on the seed signal. The power amplifier is configured to generate a laser output signal based on the flat-top pulse signal.

Abstract: A ring laser includes a large-core rare-earth-doped fiber ring-connected with a free-space path having an electro-optic switch, output coupler, and intracavity band-pass filter to enforce lasing operation in narrow wavelength range. In some cavity-dumped modes, the laser is configured in a similar manner, except that an output coupler is omitted since the optical power is extracted from the laser cavity by the electro-optic switch itself. The same laser can be configured to operate in Q-switched and/or cavity-dumping modes as well as in hybrid modes (e.g., partial Q-switch, followed by cavity dumping, or even CW). In some embodiments, the laser can be used as, or inject laser light into, a regenerative solid-state amplifier, or a Raman laser, or can be also used to generate visible, ultra-violet, mid-infrared, and far-infrared (THz) radiation via nonlinear wavelength conversion processes. The various embodiments can use a power oscillator or seed-plus-amplifier MOPA configuration.