Abstract: A ground-, sea- or aircraft-based laser transmission system can be implemented to remotely and wirelessly transmit power to an airship to be stored in an energy storage device, such as a battery. The airship can include an energy collection system having a plurality of photovoltaic cells arranged in an array and electrically coupled to the energy storage system. The energy collection system can also include one or more control link components positioned adjacent the array of photovoltaic cells. The control link components are configured to establish a control link between the airship and a power transmission system. The plurality of photovoltaic cells are configured to transfer laser beam transmitted energy from the power transmission system to the energy storage system.

Abstract: A method and apparatus for combining a plurality of laser beamlets to form a single annular beam using spectral beam combination. This invention includes a plurality of laser sources that emit a plurality of beamlets, wherein each one of the plurality of beamlets has a different wavelength; a beam annularizer that includes a plurality of optical units arranged to receive the beamlets, and configured to convert each beamlet into a respective annular beam that has an annular cross-sectional power profile; a beam-intersection transform element configured to point each respective one of the plurality of annular beams in an angular intersection arrangement toward a first location; and a spectral beam combiner at the first location configured to combine the plurality of wavelengths in the plurality of annular beams into a first annular spectrally combined beam.

Abstract: The present invention provides a method and apparatus for fabricating a grating on a silicon substrate, and the resulting grating device. In some embodiments, the apparatus method includes providing a silicon substrate; growing a diamond layer on the substrate; removing most of the silicon substrate and polishing an obverse face of the silicon to leave a very thin layer of polished silicon on the diamond layer; depositing a stack on the diamond layer, wherein the stack includes a plurality of pairs of dielectric layers on the thin layer of polished silicon, wherein each pair of the plurality of pairs of dielectric layers includes a first layer having a first index of refraction value and a second layer having a second index of refraction value that is different than the first index of refraction value; and forming a diffraction grating on an outer surface of the stack.

Abstract: 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.

Abstract: A method and apparatus for combining a plurality of laser beamlets to form a single annular beam using spectral beam combination. This invention includes a plurality of laser sources that emit a plurality of beamlets, wherein each one of the plurality of beamlets has a different wavelength; a beam annularizer that includes a plurality of optical units arranged to receive the beamlets, and configured to convert each beamlet into a respective annular beam that has an annular cross-sectional power profile; a beam-intersection transform element configured to point each respective one of the plurality of annular beams in an angular intersection arrangement toward a first location; and a spectral beam combiner at the first location configured to combine the plurality of wavelengths in the plurality of annular beams into a first annular spectrally combined beam.

Abstract: A method and apparatus for combining a plurality of laser beamlets to form a single annular beam using spectral beam combination. This invention includes a plurality of laser sources that emit a plurality of beamlets, wherein each one of the plurality of beamlets has a different wavelength; a beam annularizer that includes a plurality of optical units arranged to receive the beamlets, and configured to convert each beamlet into a respective annular beam that has an annular cross-sectional power profile; a beam-intersection transform element configured to point each respective one of the plurality of annular beams in an angular intersection arrangement toward a first location; and a spectral beam combiner at the first location configured to combine the plurality of wavelengths in the plurality of annular beams into a first annular spectrally combined beam.

Abstract: Apparatus and method for suppressing modal instabilities (MI) in fiber-amplifier systems. In some embodiments, thermal effects drive the MI process, and in some such embodiments, the present invention provides a plurality of options for mitigating these thermal effects. In some embodiments, the present invention provides a hybrid fiber with a smaller core in the initial length where the thermal loads are highest, followed by a larger-core fiber. In some embodiments the length of the smaller-core section is chosen to keep the core heat-per-unit-length of the second section below a critical value for the onset of MI. In some embodiments, the hybrid fiber of the present invention avoids modal instabilities while yielding almost the same performance as compared to conventional fibers with regard to minimizing fiber nonlinearities such as Stimulated Brillouin Scattering (SBS). In some embodiments, the hybrid fiber outputs a signal beam with at least 1 kW of power.

Abstract: A method and apparatus for combining a plurality of laser beamlets to form a single annular beam using spectral beam combination. This invention includes a plurality of laser sources that emit a plurality of beamlets, wherein each one of the plurality of beamlets has a different wavelength; a beam annularizer that includes a plurality of optical units arranged to receive the beamlets, and configured to convert each beamlet into a respective annular beam that has an annular cross-sectional power profile; a beam-intersection transform element configured to point each respective one of the plurality of annular beams in an angular intersection arrangement toward a first location; and a spectral beam combiner at the first location configured to combine the plurality of wavelengths in the plurality of annular beams into a first annular spectrally combined beam.

Abstract: 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.

Abstract: Apparatus and method for suppressing modal instabilities (MI) in fiber-amplifier systems. In some embodiments, thermal effects drive the MI process, and in some such embodiments, the present invention provides a plurality of options for mitigating these thermal effects. In some embodiments, the present invention provides a hybrid fiber with a smaller core in the initial length where the thermal loads are highest, followed by a larger-core fiber. In some embodiments the length of the smaller-core section is chosen to keep the core heat-per-unit-length of the second section below a critical value for the onset of MI. In some embodiments, the hybrid fiber of the present invention avoids modal instabilities while yielding almost the same performance as compared to conventional fibers with regard to minimizing fiber nonlinearities such as Stimulated Brillouin Scattering (SBS). In some embodiments, the hybrid fiber outputs a signal beam with at least 1 kW of power.

Abstract: 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.

Abstract: Apparatus and method for control of lasers (which use an array of optical gain fibers) in order to improve spectrally beam-combined (SBC) laser beam quality along the plane of the SBC fiber array via spectral-to-spatial mapping of a portion of the spectrally beam-combined laser beams, detection of optical power in each of the spatially dispersed beams and feedback control of the lasers for wavelength-drift correction. The apparatus includes a diffractive element; a source of a plurality of substantially monochromatic light beams directed from different angles to a single location on the diffractive element, wherein the diffractive element spectrally combines the plurality of light beams into a single beam. A controller adjusts characteristics of the light beams if one of the light beams has become misadjusted. In some embodiments, the controller adjusts the wavelength tuning of the respective fiber laser.

Abstract: Apparatus and method for generating controlled-linewidth laser-seed-signals for high-powered fiber-laser amplifier systems. In some embodiments, the natural chirp (frequency change of laser light over a short start-up time) of a DBR laser diode when driven by pulsed current is used to broaden the linewidth of the laser output, while adjusting the peak current and/or the pulse duration to obtain the desired linewidth.

Abstract: Apparatus and method for control of lasers (which use an array of optical gain fibers) in order to improve spectrally beam-combined (SBC) laser beam quality along the plane of the SBC fiber array via spectral-to-spatial mapping of a portion of the spectrally beam-combined laser beams, detection of optical power in each of the spatially dispersed beams and feedback control of the lasers for wavelength-drift correction. The apparatus includes a diffractive element; a source of a plurality of substantially monochromatic light beams directed from different angles to a single location on the diffractive element, wherein the diffractive element spectrally combines the plurality of light beams into a single beam. A controller adjusts characteristics of the light beams if one of the light beams has become misadjusted. In some embodiments, the controller adjusts the wavelength tuning of the respective fiber laser.

Abstract: A ring-laser system that includes a plurality of ring-laser gain elements and a spectral-beam-combining output stage configured to combine a plurality of beams coming from the gain elements into an output beam and that includes chromatic-dispersion compensation. In some embodiments, the output stage includes a plurality of highly reflective dielectric-coated focussing elements. In some embodiments, the output stage includes a plurality of high-efficiency dielectric-coated grating elements. In some embodiments, the output stage includes a mostly reflective but partially transmissive output mirror and a highly reflective beam-reversing mirror configured to reflect a majority of a backward-traveling signal beam such that it becomes forward traveling. In some embodiments, each gain element further includes a photonic-crystal-rod power amplifier.

Abstract: 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.

Abstract: Apparatus and method for control of lasers (which use an array of optical gain fibers) in order to improve spectrally beam-combined (SBC) laser beam quality along the plane of the SBC fiber array via spectral-to-spatial mapping of a portion of the spectrally beam-combined laser beams, detection of optical power in each of the spatially dispersed beams and feedback control of the lasers for wavelength-drift correction. The apparatus includes a diffractive element; a source of a plurality of substantially monochromatic light beams directed from different angles to a single location on the diffractive element, wherein the diffractive element spectrally combines the plurality of light beams into a single beam. A controller adjusts characteristics of the light beams if one of the light beams has become misadjusted. In some embodiments, the controller adjusts the wavelength tuning of the respective fiber laser.

Abstract: 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.

Abstract: Apparatus and method for generating controlled-linewidth laser-seed-signals for high-powered fiber-laser amplifier systems. In some embodiments, the natural chirp (frequency change of laser light over a short start-up time) of a DBR laser diode when driven by pulsed current is used to broaden the linewidth of the laser output, while adjusting the peak current and/or the pulse duration to obtain the desired linewidth.

Abstract: Apparatus and method for control of lasers (which use an array of optical gain fibers) in order to improve spectrally beam-combined (SBC) laser beam quality along the plane of the SBC fiber array via spectral-to-spatial mapping of a portion of the spectrally beam-combined laser beams, detection of optical power in each of the spatially dispersed beams and feedback control of the lasers for wavelength-drift correction. The apparatus includes a diffractive element; a source of a plurality of substantially monochromatic light beams directed from different angles to a single location on the diffractive element, wherein the diffractive element spectrally combines the plurality of light beams into a single beam. A controller adjusts characteristics of the light beams if one of the light beams has become misadjusted. In some embodiments, the controller adjusts the wavelength tuning of the respective fiber laser.