Abstract: A hybrid laser source including a solid state laser driven by an array of fiber laser amplifiers, the inputs of which are controllable in phase and polarization, to compensate for distortions that arise in the solid state laser, or to achieve desired output beam properties relating to direction or focus. The output beam is sampled and compared with a reference beam to obtain phase and polarization difference signals across the output beam cross section, at spatial positions corresponding with the positions of the fiber laser amplifiers providing input to the solid state laser. Therefore, phase and polarization properties of the output beam may be independently controlled by predistortion of these properties in the fiber laser amplifier inputs.

Abstract: A laser array architecture scalable to very high powers by closely stacking fiber amplifiers, but in which the output wavelength is selectable to be in the visible or ultraviolet region, without being restricted by the wavelengths usually inherent in the choice of fiber materials. A pump signal at a fundamental frequency is amplified in the fiber amplifier array and input to an array of nonlinear crystals that function as harmonic generators, producing an output array at a desired harmonic of the fundamental frequency. A phase detection and correction system maintains the array of outputs in phase coherency, resulting in a high power output with high beam quality, at the desired frequency. The array of nonlinear crystals may a single array to produce a second harmonic output frequency, or a combination of multiple cascaded arrays configured to produce a selected higher order harmonic frequency.

Abstract: A laser array architecture scalable to very high powers by fiber amplifiers, but in which the output wavelength is selectable, and not restricted by the wavelengths usually inherent in the choice of fiber materials. A pump beam at a first frequency is amplified in the fiber amplifier array and is mixed with a secondary beam at a second frequency to yield a frequency difference signal from each of an array of optical parametric amplifiers. A phase detection and correction system maintains the array of outputs from the amplifiers in phase coherency, resulting in a high power output at the desired wavelength. A degenerate form of the architecture is disclosed in an alternate embodiment, and a third embodiment employs dual wavelength fiber amplifiers to obtain an output at a desired difference frequency.

Abstract: A high-energy optical beam generator providing a desired output waveform. The generator includes a master oscillator, such as a mode-locked laser, to generate an input beam, a first dispersive element to decompose the input beam into frequency components, a set of phase and amplitude modulators to modulate the frequency components individually, a set of power amplifiers to amplify the frequency components individually, and a second dispersive element to recombine the amplified and modulated frequency components into a single output beam. Phase control electronics control the modulators to provide the desired waveform for the output beam, based on its intended application and on sensed characteristics of the input beam and the output beam.

Abstract: Briefly, the present invention relates to a system for combining the output light beams of a plurality of semiconductor laser diodes, for example, to form a combined light beam with increased brightness. The output light beams from the semiconductor laser diodes are coupled to a plurality of optical fibers forming a fiber coupled diode array. The optical fibers forming the fiber coupled diode array are coupled to a dual clad optical fiber with a central core. The output light beams from the optical fibers from the fiber coupled diode array are coupled to the inner cladding of a dual clad optical fiber. A Stokes seed source is applied to the central core, and the inner-clad diode light acts as a pump source to amplify the Stokes beam by stimulated Ramans scattering, thereby transferring power from the inner cladding into Stokes beam in the central core.

Abstract: A relatively high power fiber laser with an output wavelength in a spectral region considered to be “eye-safe” is disclosed. The high power fiber laser includes one or more fiber lasers that are fiber coupled, bundled and tapered into a multi-mode fiber. The multi-mode fiber is coupled into a hollow core, photonic band gap optical fiber filled with a Raman medium. In particular, fiber lasers formed from Yttrebium fibers having a nominal output wavelength of 1060-1120 nanometers are shifted to the eye-safe wavelength range by way of a hollow core photonic bond gap (PBG) filled with deuterium (D2) gas. Diode lasers having an output wavelength in the range of 940-980 nanometers can also be shifted to an eye-safe wavelength by direct Raman shifting of fiber coupled diode array to a hollow core PBG fiber filled with hydrogen (H2 gas).

Abstract: An optical system (10) that couples pump light (30) into a signal fiber (12) of a fiber array laser/amplifier. The system (10) includes a tapered light guide (TLG) (24) optically coupled to the signal fiber (12) so that the signal light propagates into a single-mode core (48) extending through the TLG (24). The TLG (24) includes a diffraction grating aperture (34) through which the pump light (30) is coupled into the TLG (24). An array of diode emitters (28) is positioned adjacent to the diffraction grating aperture (34) so that the pump light (30) is diffracted into the TLG (24). The pump light (30) is reflected off of the interface (40) between the TLG (24) and air. The angle of the pump light (30) as it is reflected off of an interface (40) between the TLG (24) and air decreases so that the pump light (30) is contained within the signal fiber (12).

Abstract: A method is provided for seeding laser system (10) for single longitudinal mode oscillation. The method includes coupling laser system (10) to be seeded for single mode output to a seed laser radiation source (12). Next, the frequency capture range (44) and spacing (46) of the axial modes (42) of the cavity (24) of the laser system (10) are determined. A seed spectrum (36) is then generated from the seed laser radiation source (12) with a bandwidth (40) corresponding to the axial mode spacing (46). The seed spectrum (36) includes a comb of discrete frequency components (38) with one or more of the discrete frequency components (38) being within the frequency capture range (44) of at least one of the axial modes (42). The seed spectrum (36) is then injected into the cavity (24) such that at least one of the axial modes (42) oscillates with the seed radiation.

Abstract: A compact fiber packaging system for fiber lasers is provided that comprises a series of spools nested inside one another for efficient volume utilization. The spools comprise an inner spool nested inside at least one outer spool to form a module. Generally, the fiber lasers are wrapped around the inner spool, and then around successive outer spools as required to form the module. Furthermore, the modules may be stacked to form a fiber assembly. The compact fiber packaging system further comprises devices and methods for minimizing thermal gradients between fibers and for removing Waste heat from the system. Additionally, the available volume is further utilized by disposing equipment and materials for operation of the fibers inside a hollow center defined by the inner spool, between the nested spools, and adjacent the nested spools.

Abstract: An optical system (10) that couples pump light (30) into a signal fiber (12) of a fiber array laser/amplifier. The system (10) includes a tapered light guide (TLG) (24) optically coupled to the signal fiber (12) so that the signal light propagates into a single-mode core (48) extending through the TLG (24). The TLG (24) includes a diffraction grating aperture (34) through which the pump light (30) is coupled into the TLG (24). An array of diode emitters (28) is positioned adjacent to the diffraction grating aperture (34) so that the pump light (30) is diffracted into the TLG (24). The pump light (30) is reflected off of the interface (40) between the TLG (24) and air. The angle of the pump light (30) as it is reflected off of an interface (40) between the TLG (24) and air decreases so that the pump light (30) is contained within the signal fiber (12).

Abstract: An optical collimator system for a high power fiber laser system that collimates the individual light beams amplified by a plurality of fibers in the laser system. The fibers are optically coupled to undoped fibers and the fibers are optically coupled to one surface of an optical substrate. A registration guide precisely aligns the fibers to the substrate. Lenses are optically coupled to an opposing surface of the substrate in precise alignment with the optical fibers. The light beam from each fiber propagates through the substrate and diverges, and the associated lens collimates the beam to have a desired beam width and direction. Each lens includes an anti-reflective coating so that the optical beam from the fiber is not significantly reflected back through the substrate.

Abstract: A seed laser apparatus is disclosed. It comprises a distributed feedback laser system for transmitting a dithered optical signal having a frequency versus time characteristic that is represented by a triangular waveform and an optical medium including a plurality of optical signal paths, each path including an optical fiber and a fiber amplifier. The optical medium is characterized by stimulated Brillouin scattering (SBS) having a response time, whereby the period of the triangular waveform is equal to the round-trip transit time in the fiber or shorter than the response time of the SBS.

Abstract: A scalable high power laser system includes a plurality of parallel connected modular power amplifier arms, coupled to a common master oscillator to provide a high average power laser system with a scalable output power level, particularly suitable for laser weapon systems with varying power level output applications. Adaptive optics devices are provided in order to provide pre-compensation of phase front distortions due to the modular amplifier arms as well as encode the wave front of the laser beam with a phase conjugate of atmospheric aberrations.

Abstract: A scalable high power laser system includes a plurality of parallel connected modular power amplifier arms, coupled to a common master oscillator to provide a high average power laser system with a scalable output power level, particularly suitable for laser weapon systems with varying power level output applications. Adaptive optics devices are provided in order to provide pre-compensation of phase front distortions due to the modular amplifier arms as well as encode the wave front of the laser beam with a phase conjugate of atmospheric aberrations.

Abstract: A single-mode fiber laser (66) that provides increased power. The fiber laser (66) includes a fiber ribbon (30) having a plurality of parallel waveguides (10). Each waveguide (10) includes a rectangular shaped core (12) that has a relatively thin dimension in one direction and a relatively wide dimension in an orthogonal direction. A step-index cladding (14, 16) is provided in the thin direction to limit the propagation of light in the core (12) to a single mode in that direction. Mode filters (18, 20) are provided adjacent the ends of the core (12) in the thickness direction and the various propagation modes in the core (12) enter the mode filters (18, 20). The mode filters (18, 20) guide the desirable single-mode back into the core (12) and reject the other modes away from the core (12). Light absorbing layers (22, 24) are provided adjacent the mode filters (18, 20) and opposite the core (12) to absorb the undesirable propagation modes of light.

Abstract: A scalable high power laser system includes a plurality of parallel connected modular power amplifier arms, coupled to a common master oscillator to provide a high average power laser system with a scalable output power level, particularly suitable for laser weapon systems with varying power level output applications. Adaptive optics devices are provided in order to provide pre-compensation of phase front distortions due to the modular amplifier arms as well as encode the wave front of the laser beam with a phase conjugate of atmospheric aberrations.

Abstract: The present invention relates generally to an apparatus that increases the conversion efficiency of optical parametric oscillators. The apparatus comprises an intracavity difference-frequency mixing optical parametric oscillator structure which receives a pulsed-pump beam from an optical pump source. The pump beam is received through an input mirror of a singly resonant cavity having an input and output end. Located within the singly resonant cavity are first and second nonlinear crystals for receiving the pump beam. The first crystal produces signal and idler waves which are received into the second crystal which produces additional idler frequency and a difference-frequency. An output mirror positioned at the output end of the cavity is totally reflective to the signal frequency and fully contains the signal frequency within the resonator cavity.

Abstract: A relatively high average power optical laser utilizes a diode pumped multi-mode dual-clad fiber amplifier configured for double pass amplification to provide a relatively higher average power than single mode fiber amplifiers. In order to compensate for mode scrambling and depolarization from the multi-mode fiber amplifier, the output beam from the multi-mode fiber amplifier is applied to a vector phase conjugator after a single pass through the amplifier and reflected back into the amplifier. The vector phase conjugator conjugates the electric field amplitude, phase and polarization and reflects a conjugate wave back into the multi-mode fiber amplifier in a reverse direction. The propagation of the conjugate wave through the amplifier unscrambles mode mixing and restores the beam back to its original polarization state. A Faraday rotator and polarization beam splitter are used to outcouple an output beam after the second pass through the multi-mode fiber amplifier.

Abstract: An optical wavelength converter apparatus that employs quasi-phase-matched parametric interaction or sum/harmonic frequency generation of electromagnetic radiation within a slab of optical material. The optical wavelength converter apparatus uses a zig-zag electromagnetic beam path in an optically flat and parallel slab on which total internal reflection from upper and lower surfaces provides a phase shift for phase matching for each leg of the zig-zag path.

Abstract: A heterodyne velocimeter system includes an illumination laser that illuminates a moving object with a coherent, laser beam. The laser illumination is reflected from the object as separate wavefronts (referred to as the signal light) and is passed through a range-focus lens pair, a polarizer element and through a partially reflective, partially transmissive element onto a plurality of separate light sensitive elements of a sensor which are referred to as pixels. A second source of laser illumination, such as a second laser provides a reference light beam that is directed onto a local oscillator scatter mask. The light beam from the second laser is scattered into separate wavefronts by the scatter mask and they are focussed by a lens onto the partially reflective partially transmissive element which reflects them onto the separate pixels of the sensor where they are individually mixed with the separate signal light wavefronts from the object.