Patents Assigned to SDL, Inc.
  • Patent number: 6367335
    Abstract: A strain sensor is disclosed for example for use in a Bragg fiber grating, in which piezoelectric actuators are arranged to compress or extend the fiber, and a capacitance micrometer for measuring the strain on the fiber in a servo loop with the actuators to provide a tunable grating in which the selected wavelength is a unique and linear function of the control command parameter. The micrometer electrodes can be placed on opposing faces of ferrules on the fiber, or capacitance between a coating directly on the fiber and a reference electrode can be used.
    Type: Grant
    Filed: January 21, 2000
    Date of Patent: April 9, 2002
    Assignee: SDL, Inc.
    Inventors: Thomas Rudolph Hicks, Newrick Kenneth Reay, Paul David Atherton
  • Patent number: 6356574
    Abstract: A multistage optical amplifier pumping system with built-in redundant reliability for lightwave communication system provides plural levels of redundancy. A first level of redundancy deals with redundancy in the form of plural primary laser diode sources for pumping a single fiber laser pump source. A second level of redundancy deals with redundancy of a plurality of fiber laser pump sources for pumping a plurality of serially connected injection signal fiber amplifiers forming the multistage amplifier system. If one of fiber pump sources should fail, increased pumping power is available from the remaining fiber pump sources via their respectively connected amplifier stages. A third level of redundancy deals with redundancy in the employment of multiple single mode laser emitters on the same chip or bar sufficiently segmented and/or electrical isolated so as not to interfere with operation of or cause failure to adjacent or neighboring emitters on the same chip or bar.
    Type: Grant
    Filed: January 29, 1999
    Date of Patent: March 12, 2002
    Assignee: SDL, Inc.
    Inventors: Richard R. Craig, Robert L G. Waarts, David F. Welch, John G. Endriz, Dirk J. Kuizenga, Steven Sanders
  • Patent number: 6353499
    Abstract: An optical fiber amplifier has an amplification stage that uses an optical fiber pumped with pump energy of a first wavelength that oscillates through the gain medium. In one embodiment, the pumping is essentially a cavity resonator that is coupled to either end of the optical fiber such that oscillating pump energy is directed into one end of the fiber and out the other, as it reflects back and forth between the ends of the cavity. Highly reflective gratings are used to maintain the oscillation of the pump energy, and a pump energy source, such as pumped doped optical fiber, is coupled to at least one of the gratings. In another embodiment, the pump source comprises multiple reflectors that are employed at each end of the fiber, and independent pump sources each having a slightly different wavelength within the absorption spectrum of the amplifier are coupled together, such that two pump wavelengths are simultaneously oscillated through the gain medium.
    Type: Grant
    Filed: August 31, 1999
    Date of Patent: March 5, 2002
    Assignee: SDL, Inc.
    Inventors: Raymond Zanoni, Robert Waarts
  • Patent number: 6347100
    Abstract: A fiber laser uses a mechanism to prevent a thermally induced shift of the gain spectrum to a range that causes the laser to become destabilized when operated at a first signal wavelength. By establishing a nominal gain spectrum that is further from the undesired range than in a conventional laser, a gain spectrum shift does not reach the undesired wavelength range. This may be accomplished by decreasing the reflectivity of a resonant cavity of the laser, such as by angling the reflective end of the cavity. It may also be accomplished by increasing the population inversion of the laser. Using a pump energy reflector to prevent pump energy from exiting the inner cladding of a double-clad version of the laser the fiber may increase population inversion. The fiber length may also be shortened or the diameter of the inner cladding reduced to increase the population inversion before a laser output is achieved.
    Type: Grant
    Filed: October 15, 1999
    Date of Patent: February 12, 2002
    Assignee: SDL, Inc.
    Inventors: Steven Sanders, Bernard G. Fidric
  • Patent number: 6347007
    Abstract: A high power laser optical amplifier system for material processing comprises multiple stage fiber amplifiers with rejection of propagating ASE buildup in and between the amplifier stages as well as elimination of SBS noise providing output powers in the range of about 10 &mgr;J to about 100 &mgr;J or more. The system is driven with a time varying drive signal from a modulated semiconductor laser signal source to produce an optical output allowing modification of the material while controlling its thermal sensitivity by varying pulse shapes or pulse widths supplied at a desire repetition rate via modulation of a semiconductor laser signal source to the system to precisely control the applied power application of the beam relative to the thermal sensitivity of the material to be processed. The high power fiber amplifier system has particular utility in high power applications requiring process treatment of surfaces, such as polymeric, organic, ceramic and metal surfaces, e.g.
    Type: Grant
    Filed: June 2, 2000
    Date of Patent: February 12, 2002
    Assignee: SDL, Inc.
    Inventors: Stephen G. Grubb, David F. Welch, Raymond Zanoni
  • Patent number: 6345141
    Abstract: A double-clad optical fiber has an inner cladding that has a torsional stress induced within it during manufacture. By rotating the fiber preform before curing of the inner cladding layer, a physical stress may be permanently imparted to the inner cladding that interacts with pump energy within the inner cladding layer to encourage mode mixing. As the cladding modes are disturbed by the stresses in the fiber, they are redirected so that the light in them intersects the core.
    Type: Grant
    Filed: December 5, 2000
    Date of Patent: February 5, 2002
    Assignee: SDL, Inc.
    Inventors: Stephen G. Grubb, David F. Welch
  • Patent number: 6335941
    Abstract: A high power laser optical amplifier system for material processing comprises multiple stage fiber amplifiers with rejection of propagating ASE buildup in and between the amplifier stages as well as elimination of SBS noise providing output powers in the range of about 10 &mgr;J to about 100 &mgr;J or more. The system is driven with a time varying drive signal from a modulated semiconductor laser signal source to produce an optical output allowing modification of the material while controlling its thermal sensitivity by varying pulse shapes or pulse widths supplied at a desire repetition rate via modulation of a semiconductor laser signal source to the system to precisely control the applied power application of the beam relative to the thermal sensitivity of the material to be processed. The high power fiber amplifier system has particular utility in high power applications requiring process treatment of surfaces, such as polymeric, organic, ceramic and metal surfaces, e.g.
    Type: Grant
    Filed: May 15, 2000
    Date of Patent: January 1, 2002
    Assignee: SDL, Inc.
    Inventors: Stephen G. Grubb, David F. Welch, Raymond Zanoni
  • Patent number: 6330257
    Abstract: The effectiveness of reflected light to stabilize the operational characteristics of a semiconductor diode laser varies with the polarization orientation of the reflected light. Stabilization failure can occur if the polarization orientation of the reflected light is orthogonal to the polarization of the light emitted by the laser source. The use of multiple reflectors can reduce the probability of stabilization failure by arranging the reflectors to return to the laser source portions of light having polarization orientations that are statistically independent with respect to each other.
    Type: Grant
    Filed: August 4, 1999
    Date of Patent: December 11, 2001
    Assignee: SDL, Inc.
    Inventors: Jo S. Major, Jr., Garnet Luick, Ian J. Booth, David C. Dawson, Fritz Christo, Robert G. Waarts
  • Patent number: 6304585
    Abstract: Laser diode pumped mid-IR wavelength sources include at least one high power, near-IR wavelength, injection and/or sources wherein one or both of such sources may be tunable providing a pump wave output beam to a quasi-phase matched (QPM) nonlinear frequency mixing (NFM) device. The NFM device may be a difference frequency mixing (DFM) device or an optical parametric oscillation (OPO) device. Wavelength tuning of at least one of the sources advantageously provides the ability for optimizing pump or injection wavelengths to match the QPM properties of the NFM device enabling a broad range of mid-IR wavelength selectivity. Also, pump powers are gain enhanced by the addition of a rare earth amplifier or oscillator, or a Raman/Brillouin amplifier or oscillator between the high power source and the NFM device. Further, polarization conversion using Raman or Brillouin wavelength shifting is provided to optimize frequency conversion efficiency in the NFM device.
    Type: Grant
    Filed: December 11, 2000
    Date of Patent: October 16, 2001
    Assignee: SDL, Inc.
    Inventors: Steven Sanders, Robert J. Lang
  • Patent number: 6301273
    Abstract: A frequency conversion system includes at least one source providing a first near-IR wavelength output including a gain medium for providing high power amplification, such as double clad fiber amplifier, a double clad fiber laser or a semiconductor tapered amplifier to enhance the power output level of the near-IR wavelength output. The NFM device may be a difference frequency mixing (DFM) device or an optical parametric oscillation (OPO) device. Pump powers are gain enhanced by the addition of a rare earth amplifier or oscillator, or a Ra-man/Brillouin amplifier or oscillator between the high power source and the NFM device.
    Type: Grant
    Filed: December 11, 2000
    Date of Patent: October 9, 2001
    Assignee: SDL, Inc.
    Inventors: Steven Sanders, Robert J. Lang, Robert G. Waarts
  • Patent number: 6301272
    Abstract: A fiber laser or fiber amplifier uses resonant pumping of the gain medium by providing a pump resonator that establishes a resonator cavity at the pump wavelength which includes the pumped gain medium. The pump resonator may be of a distributed feedback (DFB) or a distributed Bragg reflector (DBR) type construction, and may be combined with signal reflection apparatus of either DFB or DBR type construction that provides oscillation of the desired laser output wavelength. If used without a signal reflection apparatus, the invention may be operated as a resonant pumped fiber amplifier. A resonant pumped laser may use a wavelength stabilized pump source to maximize pumping efficiency, the stabilization being provided by optical feedback.
    Type: Grant
    Filed: February 15, 2000
    Date of Patent: October 9, 2001
    Assignee: SDL, Inc.
    Inventors: Thomas L. Koch, Robert Waarts
  • Patent number: 6301271
    Abstract: A frequency conversion system comprises first and second gain sources providing first and second frequency radiation outputs where the second gain source receives as input the output of the first gain source and, further, the second gain source comprises a Raman or Brillouin gain fiber for wave shifting a portion of the radiation of the first frequency output into second frequency radiation output to provided a combined output of first and second frequencies. Powers are gain enhanced by the addition of a rare earth amplifier or oscillator, or a Raman/Brillouin amplifier or oscillator between the high power source and the NFM device. Further, polarization conversion using Raman or Brillouin wavelength shifting is provided to optimize frequency conversion efficiency in the NFM device.
    Type: Grant
    Filed: December 11, 2000
    Date of Patent: October 9, 2001
    Assignee: SDL, Inc.
    Inventors: Steven Sanders, Robert G. Waarts
  • Patent number: 6297903
    Abstract: An optical amplifier makes use of a co-propagating fiber amplifier stage and a counter propagating fiber amplifier stage. One of the stages is preferably a low noise stage, while the other is a high gain stage, typically the output stage. The low noise stage may have a small core fiber while the high gain stage has a large core fiber. Pumping energy is introduced into the amplifier by coupling a plurality of laser sources in the same wavelength range using a narrow channel wavelength division multiplexer coupler. In each stage of the amplifier, some portion of the pump energy is transferred from the pumping wavelength to the signal wavelength. In a single polarization optical signal generator embodiment, the optical signal is developed in a distributed Bragg reflector oscillator having an output Bragg grating embedded in a polarization perserving fiber. A polarization controller is used at the amplifier output to restore the single polarization which is developed in the oscillator.
    Type: Grant
    Filed: November 16, 1999
    Date of Patent: October 2, 2001
    Assignee: SDL, Inc.
    Inventors: Stephen G. Grubb, Bernard G. Fidric
  • Patent number: 6298187
    Abstract: Power scaling by multiplexing multiple fiber gain sources with different wavelengths, pulsing or polarization modes of operation is achieved through multiplex combining of the multiple fiber gain sources to provide high power outputs, such as ranging from tens of watts to hundreds of watts, provided on a single mode or multimode fiber.
    Type: Grant
    Filed: November 14, 2000
    Date of Patent: October 2, 2001
    Assignee: SDL, Inc.
    Inventors: Robert G. Waarts, David F. Welch, Stephen G. Grubb, Jean-Luc Archambault, Donald R. Scifres
  • Patent number: 6295304
    Abstract: A fiber laser or fiber amplifier uses resonant pumping of the gain medium by providing a pump resonator that establishes a resonator cavity at the pump wavelength which includes the pumped gain medium. The pump resonator may be of a distributed feedback (DFB) or a distributed Bragg reflector (DBR) type construction, and may be combined with signal reflection apparatus of either DFB or DBR type construction that provides oscillation of the desired laser output wavelength. If used without a signal reflection apparatus, the invention may be operated as a resonant pumped fiber amplifier. Multiple resonators may also be pumped by a single pump source by locating each in a different branch of a multiple branch directional coupler. If the resonators are constructed to couple their outputs away from the coupler, a plurality of different laser outputs each having a different wavelength and equal output powers is provided.
    Type: Grant
    Filed: February 15, 2000
    Date of Patent: September 25, 2001
    Assignee: SDL, Inc.
    Inventors: Thomas L. Koch, Stephen G. Grubb
  • Patent number: 6282016
    Abstract: A number of variations are provided of a device that provides an amplified single polarization optical signal. Each of these relies on the use of a non-polarization maintaining gain medium through which the signal is directed, and a polarization shifter and reflector that direct the signal back through the same gain medium with a shifted polarization state. An input polarization beamsplitter directs the returning optical signal away to an output, based on its shifted polarization state. The embodiments of the invention include the use of double-clad fiber. Multiple stages may be used to provide specific amplification parameters. In particular, a fiber with a relatively large mode field diameter may be used to enable high pulse power applications. Wavelength selective components are used in certain embodiments of the invention, to allow for wavelength selectivity, as well as a single polarization state, in amplifiers, lasers and amplified spontaneous emission (ASE).
    Type: Grant
    Filed: December 1, 1999
    Date of Patent: August 28, 2001
    Assignee: SDL, Inc.
    Inventors: Stuart MacCormack, Robert G. Waarts, Paul Freeman, Stephen G. Grubb
  • Patent number: 6275632
    Abstract: Power scaling by multiplexing multiple fiber gain sources with different wavelengths, pulsing or polarization modes of operation is achieved through multiplex combining of the multiple fiber gain sources to provide high power outputs, such as ranging from tens of watts to hundreds of watts, provided on a single mode or multimode fiber.
    Type: Grant
    Filed: November 25, 2000
    Date of Patent: August 14, 2001
    Assignee: SDL, Inc.
    Inventors: Robert G. Waarts, David F. Welch, Stephen G. Grubb, Jean-Luc Archambault, Steven Sanders, Raymond Zanoni, Donald R. Scifres
  • Patent number: 6275250
    Abstract: Double clad fiber gain medium systems particularly adapted for marking indicia on surfaces of articles are disclosed. These systems provide a modulated output from a pump or seed semiconductor laser source to a double clad fiber gain medium which provides an amplified marking output scanned over the article surface with an optical scanner forming a plurality of strokes, the completion of which results in the indicia.
    Type: Grant
    Filed: January 21, 1999
    Date of Patent: August 14, 2001
    Assignee: SDL, Inc.
    Inventors: Steven Sanders, David F. Welch, Stuart MacCormack, Ramon E. Alvarez
  • Patent number: 6272162
    Abstract: A Group III-V semiconductor optoelectronic device provides for visible wavelength light output having a more laterally uniform, high power beam profile, albeit still quasi-Gaussian. A number of factors contribute to the enhanced profile including an improvement in reducing band offset of the Group III-V deposited layers improving carrier density through a decrease in the voltage drop require to generate carrier flow; reduction of contaminants in the growth of Group III-V AlGaInP-containing layers with compositional Al, providing for quality material necessary to achieve operation at the desired visible wavelengths; the formation of an optical resonator cavity that provides, in part, weak waveguiding of the propagating light; and the utilization of a mechanism to provide for beam spreading and filing in a beam diverging gain section prior to actively aggressive gain pumping of the propagating light in the device.
    Type: Grant
    Filed: November 2, 2000
    Date of Patent: August 7, 2001
    Assignee: SDL, Inc.
    Inventors: Randall S. Geels, Ross A. Parke, David F. Welch
  • Patent number: RE37354
    Abstract: A semiconductor laser having a light amplifying diode heterostructure with a flared gain region in an external resonant cavity. The flared gain region has a narrow aperture end which may be coupled to a single mode waveguide and a wide output end. A light emitting surface of the heterostructure proximate to the wide end of the flared gain region is partially reflective and combines with an external reflector to form a resonant cavity that is effectively unstable. The intracavity light-emitting surface proximate to the narrow aperture end is antireflection coated. The external reflector may be a planar mirror or a grating reflector. A lens or an optical fiber may couple the aperture end of the flared gain region to the external reflector. Frequency-selective feedback is provided by orienting the grating reflector or providing a prism in the cavity in front of the external planar mirror. Other filtering elements may also be placed in the external cavity.
    Type: Grant
    Filed: October 15, 1999
    Date of Patent: September 4, 2001
    Assignee: SDL, Inc.
    Inventors: David F. Welch, David G. Mehuys, Donald R. Scifres