Patents by Inventor Donald Harter

Donald Harter has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20120120971
    Abstract: The invention describes classes of robust fiber laser systems usable as pulse sources for Nd: or Yb: based regenerative amplifiers intended for industrial settings. The invention modifies adapts and incorporates several recent advances in FCPA systems to use as the input source for this new class of regenerative amplifier.
    Type: Application
    Filed: December 21, 2011
    Publication date: May 17, 2012
    Applicant: IMRA AMERICA, INC.
    Inventors: Donald HARTER, Gyu CHO, Zhenlin LIU, Martin FERMANN, Xinhu GU, Salvatore NATI, Lawrence SHAH, Ingmar HARTL, Mark BENDETT
  • Patent number: 8094691
    Abstract: The invention describes classes of robust fiber laser systems usable as pulse sources for Nd: or Yb: based regenerative amplifiers intended for industrial settings. The invention modifies adapts and incorporates several recent advances in FCPA systems to use as the input source for this new class of regenerative amplifier.
    Type: Grant
    Filed: June 15, 2010
    Date of Patent: January 10, 2012
    Assignee: Imra America, Inc.
    Inventors: Donald Harter, Gyu Cho, Zhenlin Liu, Martin Fermann, Xinhua Gu, Salvatore Nati, Lawrence Shah, Ingmar Hartl, Mark Bendett
  • Patent number: 7907334
    Abstract: A chirped pulse amplifier (CPA) system having a mode-locked laser and a high-speed pulse selector, wherein the pulse selector modulates output pulses based upon an applied modulation voltage. A pulse selector may be an integrated electro-optic modulator, for example a LiNbO3 modulator, or an electro-absorption modulator. Difficulties related to free-space alignment and operational stability of some prior designs are reduced or eliminated. Fiber coupling generally simplifies beam delivery and alignment. Some embodiments include an erbium fiber (or erbium-ytterbium) based CPA system operating at a wavelength of approximately 1550 nanometers. Similar performance can be obtained at other wavelengths, for example a 1.06 micrometer Yb-doped fiber system. Moreover, high amplification and peak intensity at the output may be achieved while avoiding non-linear effects in the pulse selector, thereby providing for high intensity picosecond or femtosecond operation.
    Type: Grant
    Filed: July 14, 2009
    Date of Patent: March 15, 2011
    Assignee: Imra America, Inc.
    Inventors: Xinhua Gu, Yuzuru Uehara, Donald Harter
  • Publication number: 20090285249
    Abstract: A chirped pulse amplifier (CPA) system having a mode-locked laser and a high-speed pulse selector, wherein the pulse selector modulates output pulses based upon an applied modulation voltage. A pulse selector may be an integrated electro-optic modulator, for example a LiNbO3 modulator, or an electro-absorption modulator. Difficulties related to free-space alignment and operational stability of some prior designs are reduced or eliminated. Fiber coupling generally simplifies beam delivery and alignment. Some embodiments include an erbium fiber (or erbium-ytterbium) based CPA system operating at a wavelength of approximately 1550 nanometers. Similar performance can be obtained at other wavelengths, for example a 1.06 micrometer Yb-doped fiber system. Moreover, high amplification and peak intensity at the output may be achieved while avoiding non-linear effects in the pulse selector, thereby providing for high intensity picosecond or femtosecond operation.
    Type: Application
    Filed: July 14, 2009
    Publication date: November 19, 2009
    Inventors: Xinhua GU, Yuzuru Uehara, Donald Harter
  • Patent number: 7567376
    Abstract: A chirped pulse amplifier (CPA) system having a mode-locked laser and a high-speed pulse selector, wherein the pulse selector modulates output pulses based upon an applied modulation voltage. A pulse selector may be an integrated electro-optic modulator, for example a LiNbO3 modulator, or an electro-absorption modulator. Difficulties related to free-space alignment and operational stability of some prior designs are reduced or eliminated. Fiber coupling generally simplifies beam delivery and alignment. Some embodiments include an erbium fiber (or erbium-ytterbium) based CPA system operating at a wavelength of approximately 1550 nanometers. Similar performance can be obtained at other wavelengths, for example a 1.06 .micrometer Yb-doped fiber system. Moreover, high amplification and peak intensity at the output may be achieved while avoiding non-linear effects in the pulse selector, thereby providing for high intensity picosecond or femtosecond operation.
    Type: Grant
    Filed: July 11, 2008
    Date of Patent: July 28, 2009
    Assignee: IMRA America, Inc.
    Inventors: Xinhua Gu, Yuzuru Uehara, Donald Harter
  • Publication number: 20080273558
    Abstract: An erbium fiber (or erbium-ytterbium) based chirped pulse amplification system is illustrated. The use of fiber amplifiers operating in the telecommunications window enables the implementation of telecommunications components and telecommunications compatible assembly procedures with superior mechanical stability.
    Type: Application
    Filed: July 11, 2008
    Publication date: November 6, 2008
    Inventors: Xinhua Gu, Yuzuru Uehara, Donald Harter
  • Patent number: 7440162
    Abstract: A chirped pulse amplifier (CPA) system having a mode-locked laser and a high-speed pulse selector, wherein the pulse selector modulates output pulses based upon an applied modulation voltage. A pulse selector may be an integrated electro-optic modulator, for example a LiNbO3 modulator, or an electro-absorption modulator. Difficulties related to free-space alignment and operational stability of some prior designs are reduced or eliminated. Fiber coupling generally simplifies beam delivery and alignment. Some embodiments include an erbium fiber (or erbium-ytterbium) based CPA system operating at a wavelength of approximately 1550 nanometers. Similar performance can be obtained at other wavelengths, for example a 1.06 .micrometer Yb-doped fiber system. Moreever, high amplification and peak intensity at the output may be achieved while avoiding non-linear effects in the pulse selector, thereby providing for high intensity picosecond or femtosecond operation.
    Type: Grant
    Filed: May 17, 2006
    Date of Patent: October 21, 2008
    Assignee: IMRA America, Inc.
    Inventors: Xinhua Gu, Yuzuru Uehara, Donald Harter
  • Publication number: 20080056656
    Abstract: Various types of holey fiber provide optical propagation. In various embodiments, for example, a large core holey fiber comprises a cladding region formed by large holes arranged in few layers. The number of layers or rows of holes about the large core can be used to coarse tune the leakage losses of the fundamental and higher modes of a signal, thereby allowing the non-fundamental modes to be substantially eliminated by leakage over a given length of fiber. Fine tuning of leakage losses can be performed by adjusting the hole dimension and/or the hole spacing to yield a desired operation with a desired leakage loss of the fundamental mode. Resulting holely fibers have a large hole dimension and spacing, and thus a large core, when compared to traditional fibers and conventional fibers that propagate a single mode. Other loss mechanisms, such as bend loss and modal spacing can be utilized for selected modes of operation of holey fibers. Other embodiments are also provided.
    Type: Application
    Filed: September 6, 2007
    Publication date: March 6, 2008
    Inventors: Liang Dong, Donald Harter, William Wong
  • Publication number: 20070273960
    Abstract: By writing non-linear chirp into fiber Bragg gratings, greater control over dispersion compensation in chirped pulse amplification (CPA) systems is obtained, such that, for example, the dispersion profile of the fiber Bragg grating and a bulk compressor may be matched. An iterative method of writing the fiber grating can reduce the group delay ripple to very low levels; and adaptive control of the fiber grating dispersion profile can further reduce these levels, while in addition offering greater acceptable yield in the manufacture of such gratings. Fiber Bragg gratings may be designed so as to provide customized pulse shapes optimized for various end uses, such as micromachining, for example, and may also be used to counteract gain-narrowing in a downstream amplifier.
    Type: Application
    Filed: August 10, 2007
    Publication date: November 29, 2007
    Inventors: Martin Fermann, Gennady Imeshev, Ingmar Hartl, Donald Harter
  • Publication number: 20070109629
    Abstract: The invention describes techniques for the control of the spatial as well as spectral beam quality of multi-mode fiber amplification of high peak power pulses as well as using such a configuration to replace the present diode-pumped, Neodynium based sources. Perfect spatial beam-quality can be ensured by exciting the fundamental mode in the multi-mode fibers with appropriate mode-matching optics and techniques. The loss of spatial beam-quality in the multi-mode fibers along the fiber length can be minimized by using multi-mode fibers with large cladding diameters. Near diffraction-limited coherent multi-mode amplifiers can be conveniently cladding pumped, allowing for the generation of high average power. Moreover, the polarization state in the multi-mode fiber amplifiers can be preserved by implementing multi-mode fibers with stress producing regions or elliptical fiber cores These lasers find application as a general replacement of Nd: based lasers, especially Nd:YAG lasers.
    Type: Application
    Filed: December 22, 2006
    Publication date: May 17, 2007
    Inventors: Almantas Galvanauskas, Donald Harter, Martin Fermann, Ferenc Raksi
  • Publication number: 20070103765
    Abstract: A modular, compact and widely tunable laser system for the efficient generation of high peak and high average power ultrashort pulses. Modularity is ensured by the implementation of interchangeable amplifier components. System compactness is ensured by employing efficient fiber amplifiers, directly or indirectly pumped by diode lasers. Peak power handling capability of the fiber amplifiers is expanded by using optimized pulse shapes, as well as dispersively broadened pulses. Dispersive broadening is introduced by dispersive pulse stretching in the presence of self-phase modulation and gain, resulting in the formation of high-power parabolic pulses. In addition, dispersive broadening is also introduced by simple fiber delay lines or chirped fiber gratings, resulting in a further increase of the energy handling ability of the fiber amplifiers.
    Type: Application
    Filed: December 22, 2006
    Publication date: May 10, 2007
    Inventors: Martin Fermann, Almantas Galvanauskas, Donald Harter
  • Publication number: 20070008611
    Abstract: An erbium fiber (or erbium-ytterbium) based chirped pulse amplification system is illustrated. The use of fiber amplifiers operating in the telecommunications window enables the implementation of telecommunications components and telecommunications compatible assembly procedures with superior mechanical stability.
    Type: Application
    Filed: May 17, 2006
    Publication date: January 11, 2007
    Inventors: Xinhua Gu, Yuzuru Uehara, Donald Harter
  • Patent number: 7113327
    Abstract: An erbium fiber (or erbium-ytterbium) based chirped pulse amplification system is illustrated. The use of fiber amplifiers operating in the telecommunications window enables the implementation of telecommunications components and telecommunications compatible assembly procedures with superior mechanical stability.
    Type: Grant
    Filed: June 27, 2003
    Date of Patent: September 26, 2006
    Assignee: IMRA America, Inc.
    Inventors: Xinhua Gu, Yuzuru Uehara, Donald Harter
  • Publication number: 20060171018
    Abstract: The invention describes techniques for the control of the spatial as well as spectral beam quality of multi-mode fiber amplification of high peak power pulses as well as using such a configuration to replace the present diode-pumped, Neodynium based sources. Perfect spatial beam-quality can be ensured by exciting the fundamental mode in the multi-mode fibers with appropriate mode-matching optics and techniques. The loss of spatial beam-quality in the multi-mode fibers along the fiber length can be minimized by using multi-mode fibers with large cladding diameters. Near diffraction-limited coherent multi-mode amplifiers can be conveniently cladding pumped, allowing for the generation of high average power. Moreover, the polarization state in the multi-mode fiber amplifiers can be preserved by implementing multi-mode fibers with stress producing regions or elliptical fiber cores These lasers find application as a general replacement of Nd: based lasers, especially Nd:YAG lasers.
    Type: Application
    Filed: March 10, 2006
    Publication date: August 3, 2006
    Inventors: Almantas Galvanauskas, Donald Harter, Martin Fermann, Ferenc Raksi
  • Publication number: 20060132904
    Abstract: The invention describes techniques for the control of the spatial as well as spectral beam quality of multi-mode fiber amplification of high peak power pulses as well as using such a configuration to replace the present diode-pumped, Neodynium based sources. Perfect spatial beam-quality can be ensured by exciting the fundamental mode in the multi-mode fibers with appropriate mode-matching optics and techniques. The loss of spatial beam-quality in the multi-mode fibers along the fiber length can be minimized by using multi-mode fibers with large cladding diameters. Near diffraction-limited coherent multi-mode amplifiers can be conveniently cladding pumped, allowing for the generation of high average power. Moreover, the polarization state in the multi-mode fiber amplifiers can be preserved by implementing multi-mode fibers with stress producing regions or elliptical fiber cores These lasers find application as a general replacement of Nd: based lasers, especially Nd:YAG lasers.
    Type: Application
    Filed: January 26, 2006
    Publication date: June 22, 2006
    Inventors: Almantas Galvanauskas, Donald Harter, Martin Fermann, Ferenc Raksi
  • Publication number: 20060120418
    Abstract: The invention describes classes of robust fiber laser systems usable as pulse sources for Nd: or Yb: based regenerative amplifiers intended for industrial settings. The invention modifies adapts and incorporates several recent advances in FCPA systems to use as the input source for this new class of regenerative amplifier.
    Type: Application
    Filed: December 7, 2004
    Publication date: June 8, 2006
    Inventors: Donald Harter, Gyu Cho, Zhenlin Liu, Martin Fermann, Xinhua Gu, Salvatore Nati, Lawrence Shah, Ingmar Hartl, Mark Bendett
  • Publication number: 20060093291
    Abstract: One or more single mode few-moded or multimode fibers are incorporated into a bundle to carry input to a fiber amplifier or output from a fiber amplifier or a fiber laser. The input is at the signal wavelength, which is the wavelength where amplification or lasing occurs. Each of the fibers in the bundle is cleaved individually or as a group and fiber ends are aligned in the same plane. The fiber amplifier or fiber laser may include a double clad fiber and the other fibers of the bundle couple light for cladding pumping. The device may also include a mode filter for controlling the output mode.
    Type: Application
    Filed: November 22, 2005
    Publication date: May 4, 2006
    Inventors: Liang Dong, Donald Harter
  • Publication number: 20050286569
    Abstract: An intracavity resonant Fabry-Perot saturable absorber (R-FPSA) induces modelocking in a laser such as a fiber laser. An optical limiter such as a two photon absorber (TPA) can be used in conjunction with the R-FPSA, so that Q-switching is inhibited, resulting in laser output that is cw modelocked. By using both an R-FPSA and a TPA, the Q-switched modelocked behavior of a fiber laser is observed to evolve into cw modelocking.
    Type: Application
    Filed: August 5, 2005
    Publication date: December 29, 2005
    Inventors: Min Jiang, Donald Harter, Gregg Sucha, Martin Fermann
  • Publication number: 20050243409
    Abstract: The invention describes techniques for the control of the spatial as well as spectral beam quality of multi-mode fiber amplification of high peak power pulses as well as using such a configuration to replace the present diode-pumped, Neodynium based sources. Perfect spatial beam-quality can be ensured by exciting the fundamental mode in the multi-mode fibers with appropriate mode-matching optics and techniques. The loss of spatial beam-quality in the multi-mode fibers along the fiber length can be minimized by using multi-mode fibers with large cladding diameters. Near diffraction-limited coherent multi-mode amplifiers can be conveniently cladding pumped, allowing for the generation of high average power. Moreover, the polarization state in the multi-mode fiber amplifiers can be preserved by implementing multi-mode fibers with stress producing regions or elliptical fiber cores These lasers find application as a general replacement of Nd: based lasers, especially Nd:YAG lasers.
    Type: Application
    Filed: June 1, 2005
    Publication date: November 3, 2005
    Inventors: Donald Harter, Martin Fermann
  • Patent number: RE45177
    Abstract: Use of quasi-phase-matched (QPM) materials for parametric chirped pulse amplification (PCPA) substantially reduces the required pump peak power and pump brightness, allowing exploitation of spatially-multimode and long duration pump pulses. It also removes restrictions on pump wavelength and amplification bandwidth. This allows substantial simplification in pump laser design for a high-energy PCPA system and, consequently, the construction of compact diode-pumped sources of high-energy ultrashort optical pulses. Also, this allows elimination of gain-narrowing and phase-distortion limitations on minimum pulse duration, which typically arise in a chirped pulse amplification system. One example of a compact source of high-energy ultrashort pulses is a multimode-core fiber based PCPA system. Limitations on pulse energy due to the limited core size for single-mode fibers are circumvented by using large multimode core.
    Type: Grant
    Filed: March 26, 2003
    Date of Patent: October 7, 2014
    Assignee: IMRA America, Inc.
    Inventors: Almantas Galvanauskas, Donald Harter, Gregg Sucha