Lockheed Martin Corporation

Aculight Corporation

Other

Spectra-physics Gmbh

Roy D Mead

Eric C Honea

Charles E Hamilton

Charles A Lemaire

Anping Liu

John D Minelly

Dennis D Lowenthal

Thomas H Loftus

Andrew J W Brown

Jason N Farmer

Charles I Miyake

Fabio Di Teodoro

Christopher D Brooks

Mark S Bowers

David C Gerstenberger

Jeffrey W Pierce

An apparatus, method and associated fiber-laser architectures for high-power pulsed operation and pumping wavelength-conversion devices. Some embodiments generate blue laser light by frequency quadrupling infrared (IR) light from Tm-doped gain fiber using non-linear wavelength conversion. Some embodiments use a fiber MOPA configuration to amplify a seed signal from a semiconductor laser or ring fiber laser. Some embodiments use the frequency-quadrupled blue light for underwater communications, imaging, and/or object and anomaly detection. Some embodiments amplitude modulate the IR seed signal to encode communication data sent to or from a submarine once the modulated light has its wavelength quartered. Other embodiments transmit blue-light pulses in a scanned pattern and detect scattered light to measure distances to objects in a raster-scanned underwater volume, which in turn are used to generate a data structure representing a three-dimensional rendition of the underwater scene being imaged for viewing by a person or for other software analysis.

Frequency quadrupled laser using thulium-doped fiber amplifier and method

High-power laser using thulium-doped fiber amplifier and frequency quadrupling for blue output

A method and apparatus use a photonic-crystal fiber having a very large core while maintaining a single transverse mode. In some fiber lasers and amplifiers having large cores problems exist related to energy being generated at multiple-modes (i.e., polygamy), and of mode hopping (i.e., promiscuity) due to limited control of energy levels and fluctuations. The problems of multiple-modes and mode hopping result from the use of large-diameter waveguides, and are addressed by the invention. This is especially true in lasers using large amounts of energy (i.e., lasers in the one-megawatt or more range). By using multiple small waveguides in parallel, large amounts of energy can be passed through a laser, but with better control such that the aforementioned problems can be reduced. An additional advantage is that the polarization of the light can be maintained better than by using a single fiber core.

Spectral beam combination of laser beams

Fiber-laser light is Raman shifted to eye-safer wavelengths prior to spectral beam combination, enabling a high-power, eye-safer wavelength directed-energy (DE) system. The output of Ytterbium fiber lasers is not used directly for spectral beam combining. Rather, the power from the Yb fiber lasers is Raman-shifted to longer wavelengths, and these wavelengths are then spectrally beam combined. Raman shifting is most readily accomplished with a 'cascaded Raman converter,' in which a series of nested fiber cavities is formed using fiber Bragg gratings.

Spectrally beam combined laser system and method at eye-safer wavelengths

In some embodiments, the present invention provides an apparatus and process wherein excess stored optical energy is removed from one or more stages in a fiber-amplifier, in order to stabilize the gain and obtain a constant level of energy per pulse. In some embodiments, a method of the invention includes providing a gain fiber, optically pumping the gain fiber using pump light, amplifying seed-signal pulses having a signal wavelength using the gain fiber to obtain amplified output pulses, and automatically limiting a gain of the gain fiber. In some embodiments, an apparatus of the invention includes a gain fiber, a source of pump light coupled to the gain fiber, a source of seed-signal pulses having a signal wavelength coupled to the gain fiber, wherein the gain fiber outputs amplified signal pulses, and an automatic-gain-control mechanism configured to limit gain of the gain fiber.

Pulse-energy-stabilization and first-pulse-suppression optical gain fiber apparatus and method

Pulse-energy-stabilization approach and first-pulse-suppression method using fiber amplifier

Apparatus and method for spectral-beam combining light from a plurality of high-power fiber lasers that, in some embodiments, use two substantially identical diffraction gratings in a parallel, mutually compensating configuration to combine a plurality of separate parallel input beams each having a slightly different successively higher wavelength into a single output beam of high quality. In other embodiments, a single diffraction grating is used to combine a plurality of different wavelengths, wherein the input laser beams are obtained from very narrow linewidth sources to reduce chromatic dispersion. In some embodiments, diagnostics and adjustments of wavelengths and/or positions and angles are made dynamically in real time to maintain the combination of the plurality input beams into a single high-quality output beam.

Method and apparatus for spectral-beam combining of fiber-amplified laser beams using high-efficiency dielectric diffractive gratings

Method and apparatus for spectral-beam combining of high-power fiber lasers

Apparatus and method for spectral-beam combining of high-power fiber lasers

A method and apparatus for improving the beam quality of the emissions from a multimode gain medium such as a broad-stripe laser through the use of SBC techniques is provided. In order to achieve the desired beam quality without a significant reduction in output power, discrete lasing regions are formed across the gain medium using an etalon or similar device located within the SBC cavity.

Spectral beam combination of broad-stripe laser diodes

A wide variety of Fiber Bragg writing devices comprising solid state lasers are provided. The solid state lasers emit moderate peak-power output beams which are suitable for efficient production of fiber Bragg gratings without causing embrittlement of the optical waveguide. These solid state lasers generate fourth harmonic output beams with wavelengths of approximately 240 nm, in order to match the primary absorption peak in the ultraviolet range for a typical optical waveguide. Some of these solid state lasers comprise a fequency-doubling crystal and a CLBO crystal used in a non-critically phase-matched orientation as a frequency-quadrupling crystal. In such lasers, both the frequency-doubling crystal and frequency-quadrupling crystal are preferably engineered to minimize or eliminate beam &ldquo;walkoff.&rdquo;

Method and apparatus for fiber bragg grating production

A laser via drilling system, and a method of use thereof, is provided. The apparatus uses two or more laser systems to achieve processing parameter flexibility. The output beams from the independently controlled laser systems are combined using a beam splitter that combines the beams into single or multiple processing beams. The operational flexibility of the system can be further enhanced through the use of multiple EO modulators and a polarization sensitive beam splitter.

Use of multiple laser sources for rapid, flexible machining and production of vias in multi-layered substrates

A method and apparatus for achieving broad gain bandwidth in a Raman amplifier using a wavelength multiplexed pump source is provided. The pump source offers high power, broad bandwidth, and the ability to tailor the pump spectrum, thus providing a means to achieve gain flattening within a specific band of the Raman amplifier. The pump source is preferably comprised of one or more multi-gain element arrays multiplexed together within a single external resonator cavity. Interposed between the array and the resonator cavity output coupler are a collimating element and a diffraction grating. The collimating element can be a refractive optic, a &frac14; pitch GRIN lens, or a reflective optic. The diffraction grating can either be transmissive or reflective. The combination of the diffraction grating and the collimating element forces each emitter within the array to lase at a distinct wavelength. In order to achieve an overall bandwidth greater than the gain bandwidth of a single emitter array, either multiple arrays of differing center wavelength are packaged together or a large array is used with a laterally varying quantum well thickness or epitaxy. An intracavity spatial filter can be used to improve the beam quality and reduce cross-talk between emitters.

Fiber raman amplifier pumped by an incoherently beam combined diode laser

A solid state laser system producing coherent radiations at deep ultraviolet wavelengths includes a solid state laser producing a first beam having a wavelength near 1 micron. The 1 micron beam is passed to both a harmonic generation stage and to a tunable optical parametric oscillator. The harmonic generation stage is configured to produce a fifth harmonic of the 1 micron beam, while the optical parametric oscillator produces a tunable beam in the near infrared spectrum (e.g., approximately 2.075 micron). The fifth harmonic and the near infrared beams are mixed in a sum frequency generator to produce a highly coherent beam in the deep ultraviolet (e.g., between approximately 180 nm to 213 nm).

Ultraviolet solid state laser, method of using same and laser surgery

A microwave oscillator frequency modulates the output of the laser system to be controlled. The modulated output passes through a molecular gas cell. The output of the molecular gas cell is detected by a square law device, which produces a signal at the desired microwave frequency only when a sideband of the modulated laser output coincides with the desired molecular transition frequency. A quadrature signal pair is produced by mixing the filtered output of the square law device with two phase-shifted signals from the microwave oscillator. The dispersion signal can be used to control the output frequency of the laser system, since its magnitude and sign are uniquely related to the required direction of correction.

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Edmonds, WA, United States of America

Roy D Mead