Method and apparatus for spectral-beam combining of fiber-amplified laser beams using high-efficiency dielectric diffractive gratings
First Claim
1. A method comprising:
- providing a plurality of laser devices each including one or more fiber gain media, wherein each of the plurality of laser devices includes a laser cavity, and wherein the plurality of laser devices includes a first laser device that emits a first laser beam at a first characteristic wavelength having a full-width half maximum (FWHM) linewidth of at most 1 nm and a second laser device that emits a second laser beam at a second characteristic wavelength having an FWHM linewidth of at most 1 nm;
providing one or more high-efficiency dielectric diffractive gratings optically coupled to receive the first and second laser beams, wherein the one or more high-efficiency dielectric diffractive gratings are located outside the laser cavities of the plurality of laser devices; and
spectrally combining the first and second laser beams into a single output beam using the one or more high-efficiency dielectric diffractive gratings.
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Abstract
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.
75 Citations
33 Claims
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1. A method comprising:
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providing a plurality of laser devices each including one or more fiber gain media, wherein each of the plurality of laser devices includes a laser cavity, and wherein the plurality of laser devices includes a first laser device that emits a first laser beam at a first characteristic wavelength having a full-width half maximum (FWHM) linewidth of at most 1 nm and a second laser device that emits a second laser beam at a second characteristic wavelength having an FWHM linewidth of at most 1 nm; providing one or more high-efficiency dielectric diffractive gratings optically coupled to receive the first and second laser beams, wherein the one or more high-efficiency dielectric diffractive gratings are located outside the laser cavities of the plurality of laser devices; and spectrally combining the first and second laser beams into a single output beam using the one or more high-efficiency dielectric diffractive gratings. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 21, 24, 25, 30, 31, 32, 33)
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11. An apparatus comprising:
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a plurality of laser devices each including one or more fiber gain media, wherein each of the plurality of laser devices includes a laser cavity, and wherein the plurality of laser devices includes a first laser device emits a first laser beam at a first characteristic wavelength having a full-width half maximum (FWHM) linewidth of at most 1 nm and a second laser device that emits a second laser beam at a second characteristic wavelength having an FWHM linewidth of at most 1 nm; and one or more high-efficiency dielectric diffractive gratings optically coupled to receive the first and second laser beams, wherein the one or more high-efficiency dielectric diffractive gratings are located outside the laser cavities of the plurality of laser devices;
wherein the first and second laser beams are spectrally combined into a single output beam using the one or more high-efficiency dielectric diffractive gratings. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 22, 27, 28)
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20. An apparatus comprising:
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a plurality of fiber gain media configured to emit laser beams including a first fiber gain medium that emits a first laser beam at a first characteristic wavelength having a full-width half maximum (FWHM) linewidth of at most 1 nm and a second fiber gain medium that emits a second laser beam at a second characteristic wavelength having an FWHM linewidth of at most 1 nm; and means for spectrally combining the first and second laser beams into a single output beam, the means including one or more high-efficiency dielectric diffractive gratings optically coupled to receive the first and second laser beams. - View Dependent Claims (23)
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26. A method comprising:
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providing a plurality of laser devices each including one or more fiber gain media, wherein each of the plurality of laser devices includes a laser cavity, and wherein the plurality of laser devices includes a first laser device that emits a first laser beam at a first characteristic wavelength having a full-width half maximum (FWHM) linewidth of at most 1 nm and a second laser device that emits a second laser beam at a second characteristic wavelength having an FWHM linewidth of at most 1 nm; providing one or more high-efficiency dielectric diffractive gratings optically coupled to receive the first and second laser beams, wherein the one or more high-efficiency dielectric diffractive gratings are located outside the laser cavities of the plurality of laser devices; spectrally combining the first and second laser beams into a single output beam using the one or more high-efficiency dielectric diffractive gratings; configuring the plurality of laser devices to each include a diode seed laser; outputting a spectrally narrowed seed laser beam from the diode seed laser of each of the plurality of laser devices; configuring the fiber gain media of each one of the plurality of laser devices to include a respective first rare earth doped optical fiber power amplifier; receiving, into each respective first rare earth doped optical fiber power amplifier, the seed laser beam of the corresponding diode seed laser; outputting a first amplified laser beam from each respective first rare earth doped optical fiber power amplifier; configuring the fiber gain media of each of the plurality of laser devices to include a plurality of rare earth doped optical fiber power amplifiers including the first power amplifier and a second power amplifier and an optical isolator located between the first power amplifier and the second power amplifier for each laser device; passing the first amplified laser beam through the optical isolator and into the second power amplifier; further amplifying and outputting a resulting second amplified laser beam from the second power amplifier; providing an optical modulator between the first power amplifier and the second power amplifier in each one of the plurality of laser devices; and in each one of the plurality of laser devices, modulating the first amplified laser beam with the optical modulator to form a series of pulses, wherein a plurality of pulses of each series of pulses of the plurality of laser devices are synchronized to occur substantially simultaneously.
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29. An apparatus comprising:
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a plurality of laser devices each including one or more fiber gain media, wherein each of the plurality of laser devices includes a laser cavity, and wherein the plurality of laser devices includes a first laser device emits a first laser beam at a first characteristic wavelength having a full-width half maximum (FWHM) linewidth of at most 1 nm and a second laser device that emits a second laser beam at a second characteristic wavelength having an FWHM linewidth of at most 1 nm; one or more high-efficiency dielectric diffractive gratings optically coupled to receive the first and second laser beams, wherein the one or more high-efficiency dielectric diffractive gratings are located outside the laser cavities of the plurality of laser devices, wherein the first and second laser beams are spectrally combined into a single output beam using the one or more high-efficiency dielectric diffractive gratings, wherein the plurality of laser devices each include a diode seed laser that is configured to output a spectrally narrowed seed laser beam, wherein the fiber gain media of each one of the plurality of laser devices includes a respective first rare earth doped optical fiber power amplifier configured to receive the seed laser beam of the corresponding diode seed laser and to output a first amplified laser beam from each respective first rare earth fiber power amplifier, and wherein the fiber gain media of each of the plurality of laser devices includes a plurality of rare earth doped optical fiber power amplifiers including the first power amplifier and a second power amplifier and an optical isolator located between the first power amplifier and the second power amplifier for each laser device, such that the first power amplifier provides the first amplified laser beam that is passed through the optical isolator and into the second power amplifier where it is further amplified and output as a second amplified laser beam; and an optical modulator located between the first power amplifier and the second power amplifier in each one of the plurality of laser devices, wherein the first amplified laser beam is modulated with the optical modulator to form a series of pulses, and wherein a plurality of pulses of each series of pulses of the plurality of laser devices are synchronized to occur substantially simultaneously.
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Specification