Abstract: A fiber amplifier system including an optical component responsive to a seed beam and causing amplitude modulation that creates a non-uniform spectral transmission having peaks and nulls, and an actuator operable to shift the spectral transmission. The system further includes a fiber amplifier responsive to the seed beam and generating an amplified output beam and a beam sampler responsive to the output beam that provides a sample beam. A detector detects power fluctuations in the sample beam caused by the amplitude modulation, and generates a control metric identifying a magnitude of the fluctuations. A controller uses the control metric to control the actuator to cause it to make adjustments to the seed beam or to the optical component to cause the spectral transmission caused by the optical component to shift so that the peaks or nulls of the spectral transmission align with a center frequency of the seed beam.

Abstract: A fiber amplifier system including a plurality of optical components in an amplification chain that are responsive to a seed beam and that cause frequency modulation (FM) to amplitude modulation (AM) conversion to the seed beam that creates a non-uniform spectral transmission having a transmission function, where one of the optical components is a fiber amplifier generating an amplified output beam. A programmable spectral filter is controlled to pre-distort the seed beam by applying an inverse of the transmission function that creates a net uniform transmission function by equalizing a net spectral transmission profile of the seed beam at an end of the amplification chain to reduce the amplitude modulation.

Abstract: An integrated optical device that combines a diffractive optical element (DOE) to provide beam combining for coherent beams and a spectral beam combination (SBC) grating to provide beam combining for incoherent beams. The device includes a planar substrate and a reflective coating deposited on the substrate. A top dielectric layer is deposited on the reflective coating and a photoresist layer is deposited on the top dielectric layer. A periodic structure is formed into the top dielectric layer in a first direction that defines the DOE and a periodic grating having grooves is formed into the top dielectric layer in a second direction substantially orthogonal to the first direction that defines the SBC grating where the periodic structure includes periodic modulations along the length of the grooves that are orthogonal to a channel-to-channel periodicity of the periodic grating.

Abstract: A beam quality measurement system for determining beam quality of a high power laser beam from a laser system by power-in-the-bucket (PIB) measurements in a laboratory environment. The system includes a beam compressor assembly for compressing the diameter of the laser beam, and a diagnostic bench assembly that receives the reduced diameter low power beam from the beam compressor assembly. The bench assembly includes a pinhole array positioned at a focal plane of a lens and that includes a plurality of different sized pinholes and a translation stage for moving the pinhole array. The bench assembly also includes a power meter that receives the focused beam after it has passed through a pinhole in the pinhole array, where the power meter generates a signal that causes the stage to move the pinhole array to position another pinhole when the power meter identifies a maximum power received from one pinhole.

Abstract: One example includes an optical fiber device. The device includes an optical fiber core that extends axially along a length of the optical fiber device and an optical fiber cladding that surrounds the optical fiber core and extends axially along a length of the optical fiber device. The device also includes a polymer inner jacket that surrounds the optical fiber cladding and extends axially along a length of the optical fiber device. The device further includes a thermally-conductive outer jacket that surrounds the polymer inner jacket and extends axially along a length of the optical fiber device.

Abstract: An integrated optical device that combines a diffractive optical element (DOE) to provide beam combining for coherent beams and a spectral beam combination (SBC) grating to provide beam combining for incoherent beams. The device includes a planar substrate and a reflective coating deposited on the substrate. A top dielectric layer is deposited on the reflective coating and a photoresist layer is deposited on the top dielectric layer. A periodic structure is formed into the top dielectric layer in a first direction that defines the DOE and a periodic grating having grooves is formed into the top dielectric layer in a second direction substantially orthogonal to the first direction that defines the SBC grating where the periodic structure includes periodic modulations along the length of the grooves that are orthogonal to a channel-to-channel periodicity of the periodic grating.

Abstract: A fiber amplifier system including a plurality of optical components in an amplification chain that are responsive to a seed beam and that cause frequency modulation (FM) to amplitude modulation (AM) conversion to the seed beam that creates a non-uniform spectral transmission having a transmission function, where one of the optical components is a fiber amplifier generating an amplified output beam. A programmable spectral filter is controlled to pre-distort the seed beam by applying an inverse of the transmission function that creates a net uniform transmission function by equalizing a net spectral transmission profile of the seed beam at an end of the amplification chain to reduce the amplitude modulation.

Abstract: A fiber amplifier system including an optical component responsive to a seed beam and causing amplitude modulation that creates a non-uniform spectral transmission having peaks and nulls, and an actuator operable to shift the spectral transmission. The system further includes a fiber amplifier responsive to the seed beam and generating an amplified output beam and a beam sampler responsive to the output beam that provides a sample beam. A detector detects power fluctuations in the sample beam caused by the amplitude modulation, and generates a control metric identifying a magnitude of the fluctuations. A controller uses the control metric to control the actuator to cause it to make adjustments to the seed beam or to the optical component to cause the spectral transmission caused by the optical component to shift so that the peaks or nulls of the spectral transmission align with a center frequency of the seed beam.

Abstract: A fiber laser amplifier system that employs a technique for reducing polarization modulation instability (PMI) in a delivery fiber. The system includes a fiber amplifier that amplifies a seed beam and provides the amplified seed beam to a weakly polarization maintaining (PM) delivery fiber that delivers the amplified beam to a certain location. The polarization of the seed beam is controlled so that it aligns with the slow axis of the delivery fiber such that nonlinear birefringence that occurs in the delivery fiber is added to the natural birefringence of the delivery fiber so as to suppress the PMI in the delivery fiber.

Abstract: An optical fiber launcher assembly can include a low precision fiber array that outputs a plurality of optical signals from a given side that are input into an opposing side. The optical fiber launcher assembly can also include a corrective optic aligned with and spaced apart from the low precision fiber array. The plurality of optical signals output from the low precision array to the corrective optic have a given trajectory and optical signals output from the corrective optic have a substantially parallel trajectory different from the given trajectory.

Abstract: A fiber amplifier system including a plurality of seed beam sources each generating a seed beam at a different wavelength and a selection switch selectively outputting the seed beams on one or more outputs. The system also includes a plurality of fiber amplifiers each receiving one of the selected seed beams from the selection switch and a plurality of wavelength division multiplexers (WDMs) where a separate WDM receives an amplified beam from a fiber amplifier, each WDM providing the amplified beam on a separate output depending on the wavelength of the selected beam. The system further includes a plurality of beam directors each being coupled to each WDM, where one of the beam directors receives all of the amplified beams on the delivery fibers from each of the WDMs depending on the selected seed beam, each beam director combining the beams using CBC or SBC into a combined output beam.

Abstract: A system includes N master oscillators to generate N master oscillator driving signals. The system includes N splitters to split each of the N master oscillator signals into M coherent signals with M being a positive integer greater than one. A modulator and fiber amplifier stage adjusts the relative phases of the M coherent signals and generates M×N amplified signals. The M×N amplified signals are aggregated into M clusters of N fibers. The system includes M spectral beam combination (SBC) modules to combine each of the M clusters. Each SBC module combines the M×N amplified signals at N wavelengths and generates M tiled output beams. Each SBC module employs a single dimensional (1D) fiber optic array to transmit one cluster of N amplified signals from the M signal clusters and generates one tiled output beam of the M tiled output beams.

Abstract: An integrated optical device that combines a diffractive optical element (DOE) to provide beam combining for coherent beams and a spectral beam combination (SBC) grating for combining beams of differing wavelengths. The device includes a substrate where a periodic pattern for the DOE is formed in the top surface of the substrate in a first direction. A plurality of reflective layers are deposited on the substrate over the periodic pattern so that the layers follow the shape of the pattern. A top dielectric layer is deposited on the plurality of reflective layers so that the top dielectric layer also follows the shape of the periodic pattern. A periodic grating for the SBC is formed into the top dielectric layer in a second direction substantially orthogonal to the first direction.

Abstract: A fiber amplifier system including a plurality of fiber amplifiers each receiving a fiber beam and a tapered fiber bundle (TFB) combiner including a plurality of input end fibers, a plurality of output end fibers and a center bundle portion, where each input end fiber is coupled to a separate one of the fiber amplifiers, and where the bundle portion combines all of the fiber beams into a single combined beam and each output end fiber being capable of receiving the combined beam separately from the other output end fibers. The system also includes a low non-linear delivery fiber coupled to an output end fiber of the TFB combiner and an optical output turret coupled to the delivery fiber opposite to the TFB combiner, wherein the non-linear delivery fiber is configured to reduce the effect of cross-phase modulation (XPM) instability in the delivery fiber.

Abstract: A seed beam source for a fiber amplifier system. The seed beam source includes a plurality of continuous wave master oscillator lasers, each generating a laser beam at a different wavelength and a plurality of switching modulators each receiving the laser beam from a particular one of the master oscillator lasers, where each switching modulator is electrically driven so as to output the laser beam as pulses based on a predetermined timing control. The seed beam source further includes an optical coupler responsive to the optical pulses from the plurality of switching modulators where the optical coupler only receives one of the optical pulses from the plurality of switching modulators at any particular point in time, and where the optical coupler continuously receives the optical pulses from the plurality of switching modulators and outputs an interleaved continuous optical seed beam including the pulses from all of the switching modulators.

Abstract: A fiber amplifier system including at least one seed source providing an optical seed beam and a harmonic driver providing a sinusoidal drive signal at a predetermined frequency. The system also includes a harmonic phase modulator that receives the seed beam and the drive signal, where the harmonic phase modulator frequency modulates the seed beam using the drive signal so as to remove optical power from a zeroth-order frequency of the seed beam and create sidebands separated by the frequency of the drive signal. A dispersion element receives the frequency modulated seed beam and provides temporal amplitude modulation to the seed beam and a nonlinear fiber amplifier receives the amplitude modulated seed beam from the dispersion element and amplifies the seed beam, where the dispersion element and the fiber amplifier combine to remove optical power from the sidebands and put optical power back into the zeroth-order frequency.

Abstract: A method and apparatus for suppression of stimulated Brillouin scattering (SBS) includes a master oscillator (MO) that generates a beam; a birefringent element that receives and transmits the beam, wherein the beam is transmitted with a transmission delay between two orthogonal axes; a polarization controller that receives the beam and transmits the beam with a desired polarization; a fiber amplifier that receives the beam, amplifies the beam, and transmits a beam; a compensating birefringent element that receives the beam, approximately removes the transmission delay between the two axes of the beam, and transmits an output beam; and a polarization detector that detects the output beam's polarization and provides feedback to the polarization controller to ensure that the polarization of the output beam is approximately equal to a desired output polarization, so as to reduce SBS.

Abstract: An integrated optical device that combines a diffractive optical element (DOE) to provide beam combining for coherent beams and a spectral beam combination (SBC) grating for combining beams of differing wavelengths. The device includes a substrate where a periodic pattern for the DOE is formed in the top surface of the substrate in a first direction. A plurality of reflective layers are deposited on the substrate over the periodic pattern so that the layers follow the shape of the pattern. A top dielectric layer is deposited on the plurality of reflective layers so that the top dielectric layer also follows the shape of the periodic pattern. A periodic grating for the SBC is formed into the top dielectric layer in a second direction substantially orthogonal to the first direction.

Abstract: A method and apparatus for suppression of four-wave mixing using polarization control with a high power polarization maintaining fiber amplifier system. The apparatus includes a master oscillator (MO) that generates a beam; a polarization controller that receives the beam from the MO and transmits the beam with a desired polarization; a pre-amplifier that receives the beam from the polarization controller, pre-amplifies the beam, and transmits the beam; a high power fiber amplifier that receives the beam from the pre-amplifier, amplifies the beam, and transmits an output beam; and a polarization detector that detects the polarization of the output beam. The polarization detector transmits feedback to the polarization controller to ensure that the output beam components aligned with the principal birefringent axes of the high power fiber amplifier have approximately equal power.

Abstract: A method and apparatus for suppression of stimulated Brillouin scattering (SBS) includes a master oscillator (MO) that generates a beam; a birefringent element that receives and transmits the beam, wherein the beam is transmitted with a transmission delay between two orthogonal axes; a polarization controller that receives the beam and transmits the beam with a desired polarization; a fiber amplifier that receives the beam, amplifies the beam, and transmits a beam; a compensating birefringent element that receives the beam, approximately removes the transmission delay between the two axes of the beam, and transmits an output beam; and a polarization detector that detects the output beam's polarization and provides feedback to the polarization controller to ensure that the polarization of the output beam is approximately equal to a desired output polarization, so as to reduce SBS.