Method and apparatus for spectral-beam combining of high-power fiber lasers
First Claim
1. A method comprising:
- providing a plurality of fiber lasers that generate laser beams including a first fiber that generates a first laser beam and a second fiber that generates a second laser beam;
spectrally combining the plurality of laser beams into a single output beam;
wavelength tuning the first fiber to generate the first laser beam at a first wavelength;
wavelength tuning the second fiber to generate the second laser beam at a second wavelength;
detecting that one of the laser beams has become misaligned relative to the single combined beam;
determining that the first laser beam is the misaligned one; and
adjusting the wavelength tuning of the first fiber in order that the first laser beam is aligned relative to the single combined beam.
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Accused Products
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.
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Citations
34 Claims
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1. A method comprising:
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providing a plurality of fiber lasers that generate laser beams including a first fiber that generates a first laser beam and a second fiber that generates a second laser beam; spectrally combining the plurality of laser beams into a single output beam; wavelength tuning the first fiber to generate the first laser beam at a first wavelength; wavelength tuning the second fiber to generate the second laser beam at a second wavelength; detecting that one of the laser beams has become misaligned relative to the single combined beam; determining that the first laser beam is the misaligned one; and adjusting the wavelength tuning of the first fiber in order that the first laser beam is aligned relative to the single combined beam. - View Dependent Claims (2, 3, 4)
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5. A method comprising:
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providing a plurality of fiber lasers that generate laser beams including a first fiber that generates a first laser beam and a second fiber that generates a second laser beam; providing a plurality of Yb-doped multiply clad optical fibers including a first fiber and a second fiber; pumping an inner cladding of each of the plurality of fibers with pump light from one or more laser diodes; amplifying, with the first fiber, the first laser beam at a first wavelength; amplifying, with the second fiber, the second laser beam at a second wavelength; spectrally combining the plurality of laser beams into a single output beam; wavelength tuning the first fiber to generate the first laser beam at the first wavelength; wavelength tuning the second fiber to generate the second laser beam at the second wavelength; detecting that one of the laser beams has become misaligned relative to the single combined beam; determining that the first laser beam is the misaligned one; and adjusting the wavelength tuning of the first fiber in order that the first laser beam is aligned relative to the single combined beam. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
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13. A method comprising:
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providing a plurality of laser beams including a first laser beam and a second laser beam; wavelength tuning a first fiber to generate the first laser beam at a first wavelength and having a linewidth of about 1 nm or less; wavelength tuning a second fiber to generate the second laser beam at a second wavelength and having a linewidth of about 1 nm or less; and spectrally combining the plurality of laser beams into a single output beam having an output power/area of about 10 W/cm2 or more using one or more high-efficiency dielectric diffractive gratings. - View Dependent Claims (14, 15, 16)
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17. A method comprising:
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providing a plurality of laser beams including a first laser beam and a second laser beam; wavelength tuning a first fiber to generate the first laser beam at a first wavelength and having a linewidth of about 1 nm or less; wavelength tuning a second fiber to generate the second laser beam at a second wavelength and having a linewidth of about 1 nm or less; spectrally combining the plurality of laser beams into a single output beam having an output power/area of about 10 W/cm2 or more using one or more high-efficiency dielectric diffractive gratings, temporally forming the first laser beam into a first serial plurality of pulses each having a pulse length of about 10 ns or less; and temporally forming the second laser beam into a second serial plurality of pulses each having a pulse length of about 10 ns or less, wherein pulses of the first serial plurality of pulses are alternated with pulses of the second serial plurality of pulses. - View Dependent Claims (18)
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19. A method comprising:
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providing a plurality of laser beams including a first laser beam and a second laser beam; wavelength tuning a first fiber to generate the first laser beam at a first wavelength and having a linewidth of about 1 nm or less; wavelength tuning a second fiber to generate the second laser beam at a second wavelength having a linewidth of about 1 nm or less; spectrally combining the plurality of laser beams into a single output beam having an output power/area of about 10 W/cm2 or more using one or more high-efficiency dielectric diffractive gratings, providing a plurality of Yb-doped large-mode-area (LMA) optical-amplification fibers each operating substantially in the fundamental mode, including a first fiber and a second fiber; pumping of each of the plurality of fibers with pump light from one or more laser diodes; amplifying, with the first fiber, the first laser beam at a first wavelength; amplifying, with the second fiber, the second laser beam at a second wavelength; filtering the first laser beam to a full-width half-maximum linewidth of about one nanometer or less; filtering the second laser beam to a full-width half-maximum linewidth of about one nanometer or less; pulsing the first laser beam to a pulse length of about ten nanoseconds or less, and sufficiently short to substantially prevent SBS buildup in the amplifying of the first laser beam; and pulsing the second laser beam to a pulse length of about ten nanoseconds or less, and sufficiently short to substantially prevent SBS buildup in the amplifying of the second laser beam. - View Dependent Claims (20, 21)
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22. An apparatus comprising:
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a plurality of fiber lasers that generate laser beams including a first fiber that generates a first laser beam and a second fiber that generates a second laser beam; means for spectrally combining the plurality of laser beams into a single output beam; means for wavelength tuning the first fiber to generate the first laser beam at the first wavelength; means for wavelength tuning the second fiber to generate the second laser beam at the second wavelength; means for detecting that one of the laser beams has become misaligned relative to the single combined beam; means for determining that the first laser beam is the misaligned one; and means for adjusting the wavelength tuning of the first fiber in order that the first laser beam is aligned relative to the single combined beam.
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23. A method comprising:
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providing a plurality of laser beams including a first laser beam and a second laser beam; wavelength tuning a first fiber to generate the first laser beam at a first wavelength and at a sufficiently narrow linewidth and amplifying the first laser beam to a sufficiently high extent to otherwise cause stimulated Brillouin scattering (SBS) buildup in the amplifying of the first laser beam but temporally forming the first laser beam into a first serial plurality of pulses each having a pulse length sufficiently short to substantially prevent SBS buildup in the amplifying of the first laser beam; wavelength tuning a second fiber to generate the first laser beam at a second wavelength and at a sufficiently narrow linewidth and amplifying the second laser beam to a sufficiently high extent to otherwise cause SBS buildup in the amplifying of the second laser beam but temporally forming the second laser beam into a second serial plurality of pulses each having a pulse length sufficiently short to substantially prevent SBS buildup in the amplifying of the second laser beam; spectrally combining the plurality of laser beams into a single output beam using one or more high-efficiency dielectric diffractive gratings; detecting that one of the laser beams has become misaligned relative to the single combined beam; determining that the first laser beam is the misaligned one; and adjusting the wavelength tuning of the first fiber in order that the first laser beam is aligned relative to the single combined beam.
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24. A method comprising:
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providing a plurality of laser beams including a first laser beam and a second laser beam; wavelength tuning a first fiber to generate the first laser beam at a first wavelength and at a sufficiently narrow linewidth and amplifying the first laser beam to a sufficiently high extent to otherwise cause stimulated Brillouin scattering (SBS) buildup in the amplifying of the first laser beam but temporally forming the first laser beam into a first serial plurality of pulses each having a pulse length no more than about 10 nanoseconds, in order to substantially prevent SBS buildup in the amplifying of the first laser beam; wavelength tuning a second fiber to generate the first laser beam at a second wavelength and at a sufficiently narrow linewidth and amplifying the second laser beam to a sufficiently high extent to otherwise cause SBS buildup in the amplifying of the second laser beam but temporally forming the second laser beam into a second serial plurality of pulses each having a pulse length no more than about 10 nanoseconds, in order to substantially prevent SBS buildup in the amplifying of the second laser beam; and spectrally combining the plurality of laser beams into a single output beam using one or more high-efficiency dielectric diffractive gratings. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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Specification