Patents Examined by Gioacchino Inzirillo
  • Patent number: 6366598
    Abstract: A waveguide (10) is provided having a two-dimensional optical wavelength Bragg grating (20) embedded within a semiconductor laser medium (16). More particularly, the waveguide (10) includes an active region (16) sandwiched between n-doped and p-doped cladding layers (14, 22). The two-dimensional Bragg grating (20) is formed in the active region (16). Upper and lower electrodes (24, 26) are defined on opposite sides of the cladding layers (14, 22) to complete the waveguide structure (10). The two-dimensional grating (20) provides simultaneous frequency selective feedback for mode control in both the longitudinal and lateral directions.
    Type: Grant
    Filed: February 10, 1999
    Date of Patent: April 2, 2002
    Assignee: TRW Inc.
    Inventors: Doyle T. Nichols, Srinath Kalluri, Michael G. Wickham, Timothy A. Vang, Michael P. Nesnidal, Robert W. Lodenkamper
  • Patent number: 6363088
    Abstract: An optical system for generating light includes a doped fluoride fiber which is used to convert energy of light at a first frequency, supplied by an optical pump, to light at a second frequency. The second frequency may be lower (down-conversion) or higher (up-conversion) than the first frequency. The optical pump is coupled to the doped fiber. A reflector may be placed at each facet of the doped fiber to form a laser cavity. The reflectors at the facets of the fiber are tuned to a desired emission frequency of the fiber. The laser cavity may be formed either by two substantial reflectors, each positioned at a facet of the doped fiber, or by a substantial reflector, positioned at one facet of the fiber, and a partial reflector, positioned at the other facet of the fiber. When two substantial reflectors are used, other means, such as a wavelength division multiplexer or diffraction grating may be provided in the laser cavity fiber, to provide an output path for the light at the second frequency.
    Type: Grant
    Filed: November 30, 1998
    Date of Patent: March 26, 2002
    Assignee: Sarnoff Corporation
    Inventors: Gerard Argant Alphonse, Herschel Clement Burstyn, Leon Shapiro
  • Patent number: 6359918
    Abstract: A light source controller having a look-up table that indicates the amount of current to be provided to a light source to maintain wavelength and spectrum stability at various temperatures. Further, the light source may have a heater/cooler to maintain a constant temperature of the light source. The controller provides the appropriate current to the light source from the time of turn-on until it achieves thermal equilibrium, to provide an output having a relatively constant wavelength during the warm-up period and during changes of ambient temperature about the light source. The light source may have a heater and/or cooler to maintain a constant ambient temperature, so that the light source controller can provide a more refined control of the light source output wavelength and spectrum. The light source controller may be particularly used for a light source in a fiber optic gyroscope.
    Type: Grant
    Filed: June 30, 1998
    Date of Patent: March 19, 2002
    Assignee: Honeywell International Inc.
    Inventor: Michael S. Bielas
  • Patent number: 6356573
    Abstract: A top surface emitting vertical cavity laser with enhanced power handling capacity. The laser provides a patterned top electrode for uniformly injecting applied current to the active area. The diameter of the electrode relative to the vertical distance between it and the active layer is reduced by patterning. The result is an improved laser with significant power output.
    Type: Grant
    Filed: January 22, 1999
    Date of Patent: March 12, 2002
    Assignee: Mitel Semiconductor AB
    Inventors: Jan Jonsson, Vilhelm Oscarsson
  • Patent number: 6356571
    Abstract: A Vertical Cavity Surface Emitting Laser (VCSEL) (10) and a method for manufacturing the VCSEL (10). The VCSEL (10) includes a ridge structure (34), a first confinement layer (36) disposed adjacent to a portion of the ridge structure (34), and a second confinement layer (37) disposed on the first confinement layer (36) and disposed adjacent to a portion of the ridge structure (32). Carriers injected into the ridge structure (34) are confined by the first confinement layer (36).
    Type: Grant
    Filed: August 17, 2000
    Date of Patent: March 12, 2002
    Assignee: Motorola, Inc.
    Inventors: Philip Anthony Kiely, Paul Robert Claisse, Jamal Ramdani
  • Patent number: 6353623
    Abstract: Apparatus and methods for monitoring the wavelength of laser radiation and that provide a temperature-corrected error signal responsive to the deviation of the wavelength of the laser radiation from a nominal wavelength is disclosed. The apparatus includes a least one optical filter for filtering the laser radiation according to at least one spectral filter function to produce filtered laser radiation and at least one optical detector for detecting the filtered laser radiation to produce a first detected signal. The apparatus also includes a temperature sensor for sensing temperature characteristic of at least the optical filter and processing circuitry for providing a temperature-corrected output signal responsive to the deviation of the wavelength of the laser radiation from the nominal wavelength.
    Type: Grant
    Filed: January 4, 1999
    Date of Patent: March 5, 2002
    Assignee: Uniphase Telecommunications Products, Inc.
    Inventors: Timothy C. Munks, Paul E. Dunn, David J. Allie
  • Patent number: 6351478
    Abstract: A passively cooled solid-state laser system for producing high-output power is set forth. The system includes an optics bench assembly containing a laser head assembly which generates a high-power laser beam. A laser medium heat sink assembly is positioned in thermal communication with the laser medium for conductively dissipating waste heat and controlling the temperature of the laser medium. A diode array heat sink assembly is positioned in thermal communication with the laser diode array assembly for conductively dissipating waste heat and controlling the temperature of the laser diode array assembly. The heat sink assemblies include heat exchangers with extending surfaces in intimate contact with phase change material. When the laser system is operating, the phase change material transitions from solid to liquid phase.
    Type: Grant
    Filed: September 11, 1998
    Date of Patent: February 26, 2002
    Assignee: Cutting Edge Optronics, Inc.
    Inventor: Geoffrey O. Heberle
  • Patent number: 6351477
    Abstract: Optically pumped amplifiers, in particular solid-state amplifiers, comprise an amplification medium (1) and an optical pumping arrangement (5) via which the pumping radiation is coupled to the amplification medium (1), the pumping radiation being formed before coupling. The volume of the amplification medium is only partially pumped; the pumped volume of the amplification medium is approximately rectangular in cross-section and approximately perpendicular to the optical axis; and the ratio of the width to height of the rectangular cross-section is greater than 1:8.
    Type: Grant
    Filed: August 6, 1998
    Date of Patent: February 26, 2002
    Assignee: Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung E.V.
    Inventor: Keming Du
  • Patent number: 6351484
    Abstract: High-damage-threshold output couplers with reflectivities suitable for use in high-power Q-switched lasers can be constructed from two pieces of high-damage-threshold bulk material. The output couplers are formed by a thin fluid-filled gap between parallel faces of bulk materials. This forms a reflective Fabry-Perot etalon with a large bandwidth. By avoiding the use of dielectric coatings to form the output coupler, a common source of damage—optical damage to the dielectric coating—can be avoided, making it possible to produce higher-performance lasers.
    Type: Grant
    Filed: August 28, 2000
    Date of Patent: February 26, 2002
    Assignee: Massachusetts Institute of Technology
    Inventor: John J. Zayhowski
  • Patent number: 6347101
    Abstract: A solid state laser includes a high absorption coefficient solid state gain medium such as Nd:YVO4 that is side pumped with a semiconductor laser diode array. The resonant cavity of the solid state laser is positioned so that the TEM00 mode is spaced from the face of the laser through which the laser is pumped by a distance sufficient to reduce diffraction losses but sufficiently near to allow coupling of pump light into the gain mode. The gain medium, the doping level of the gain medium, and the operating temperature of the pump laser are selected to efficiently couple pump light into the gain mode. The pump laser is positioned to side pump the gain medium without collimating or focusing optics between the pump laser and the face of the gain medium. A gap between the pump laser and the gain medium is empirically selected to match the angular extent of the pump laser output light to the height of the gain mode at the position of the gain mode fixed to optimize coupling and diffraction losses.
    Type: Grant
    Filed: April 16, 1998
    Date of Patent: February 12, 2002
    Assignee: 3D Systems, Inc.
    Inventors: Xingkun Wu, Jouni P. Partanen, William F. Hug, Hamid Hemmati
  • Patent number: 6347102
    Abstract: A wavelength conversion laser for generating sum frequency laser beam comprising a laser resonator, a solid-state laser active medium, a second harmonic generation wavelength conversion crystal and a sum frequency generation wavelength conversion crystal, wherein the length of the second harmonic generation wavelength conversion crystal along the optical axis is set to be shorter than that of the sum frequency generation wavelength conversion crystal.
    Type: Grant
    Filed: November 17, 1999
    Date of Patent: February 12, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Susumu Konno, Koji Yasui, Kenji Kumamoto, Kuniaki Iwashiro
  • Patent number: 6343087
    Abstract: An active layer is formed on the principal surface of a semiconductor substrate continuously at least from a laser output plane to a laser reflection plane, the active layer being gradually thinned toward the output plane in a region to a certain distance from the output plane toward the reflection plane. A ridge is formed on the active layer, extending from the output plane to the reflection plane and gradually increasing a width toward the output plane in a region to a first distance from the output plane, an upper surface of the ridge in a first region to a second distance from the output plane being set higher than an upper surface of the ridge in a second region other than the first region. A mesa structure is formed on the principal surface of the semiconductor substrate in areas on both sides of the ridge, the mesa structure having an upper surface defining a virtual flat plane at a position flush with or higher than a highest upper surface of the ridge.
    Type: Grant
    Filed: September 16, 1998
    Date of Patent: January 29, 2002
    Assignee: Fujitsu Limited
    Inventor: Tsuyoshi Yamamoto
  • Patent number: 6333943
    Abstract: After forming domain inverted layers 3 in an LiTaO3 substrate 1, an optical waveguide is formed. By performing low-temperature annealing for the optical wavelength conversion element thus formed, a stable proton exchange layer 8 is formed, where an increase in refractive index generated during high-temperature annealing is lowered, thereby providing a stable optical wavelength conversion element. Thus, the phase-matched wavelength becomes constant, and variation in harmonic wave output is eliminated. Consequently, with respect to an optical wavelength conversion element utilizing a non-linear optical effect a highly reliable element is provided.
    Type: Grant
    Filed: March 16, 1998
    Date of Patent: December 25, 2001
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Kazuhisa Yamamoto, Kiminori Mizuuchi, Yasuo Kitaoka, Makoto Kato
  • Patent number: 6331993
    Abstract: A diode-pumped gas laser includes a source of optical diode-pumping light and a gas cell having a first optical window for receiving the diode-pumping light. The gas cell contains a laser gas including a lasing gas comprised of at least one absorbing and lasing atomic or molecular gas. The lasing gas has an optical absorption band which is at least partially overlapped by the bandwidth of the diode-pumping light. The gas laser also includes a gas laser resonator for providing an output laser beam which is emitted from the gas cell via a second optical window. The output laser beam has one or more laser wavelengths. The gas laser may also include diode optics for directing the diode-pumping light through the first optical window and a heat power regulation system for regulating the temperature of the source of optical diode-pumping light.
    Type: Grant
    Filed: January 28, 1999
    Date of Patent: December 18, 2001
    Inventor: David C. Brown
  • Patent number: 6331990
    Abstract: The present invention demodulates a FM, WM or AM optical input beam, amplifies the signal impressed on the beam, and then modulates without intervening electronics the signal amplitude of an output beam. The apparatus can be made from any semiconductor laser, including edge-emitting lasers and VCSELs. Light transmitted through the waveguide (the “control beam”) interacts with the carrier population of the laser, reducing the available gain and thereby the output intensity. The present invention has three key advantages: (i) a FM control beam produces an amplitude-modulated output beam from the main-laser, (ii) the amplitude of the AM beam depends directly on the differential gain ∂G/∂&ohgr;, and (iii) the apparatus and method provides gain for all LOGiC devices. The present invention works with available and future semiconductor lasers, including those emitting in the blue as well as those operating at 670, 850, 980, 1300, and 1500 nm.
    Type: Grant
    Filed: February 1, 1999
    Date of Patent: December 18, 2001
    Assignee: The United States of America as represented by the Secretary of the Air Force
    Inventors: Michael A. Parker, Douglas B. Shire, Chung L. Tang
  • Patent number: 6330264
    Abstract: A laser diode pump for fiber amplifiers, such as erbium-doped fiber amplifiers (EDFAs), reduces spurious reflections in the signal frequencies by providing a laser pump system that is dissipative at these signal frequencies. Reflections from the pump system are reduced, or eliminated by using an output facet that is currently coated to be reflective at pump frequencies, but anti-reflective, or transmissive, at the signal frequencies. In one embodiment, material layers of aluminum oxide (Al2O3), titanium dioxide (TiO2), and silicon dioxide (SiO2) are used.
    Type: Grant
    Filed: January 18, 1999
    Date of Patent: December 11, 2001
    Assignee: Corning Lasertron, Inc.
    Inventor: Andreas Kussmaul
  • Patent number: 6327289
    Abstract: A wavelength-variable semiconductor laser includes: a submount; and a semiconductor laser chip being mounted onto the submount and having at least an active layer region and a distributed Bragg reflection region, wherein the semiconductor laser chip is mounted onto the submount in such a manner that an epitaxial growth surface thereof faces the submount and a heat transfer condition of the active layer region is different from a heat transfer condition of the distributed Bragg reflection region. Moreover, an optical integrated device includes at least a semiconductor laser and an optical waveguide device both mounted on a submount, wherein the semiconductor laser is the wavelength-variable semiconductor laser as set forth above.
    Type: Grant
    Filed: September 2, 1998
    Date of Patent: December 4, 2001
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yasuo Kitaoka, Kiminori Mizuuchi, Kazuhisa Yamamoto
  • Patent number: 6327278
    Abstract: The invention concerns a multimode waveguide laser (1, 2, 3, 5) which is characterized by the fact that the waveguide's cutoff wavelength is smaller than the smallest wavelength of the emission spectrum of the waveguide laser. Advantageously, the waveguide laser and te diode laser (6) in the wavelength range of the waveguide laser emission are optically decoupled, thus making the diode laser pumped waveguide laser specially suitable for intra-cavity spectroscopy.
    Type: Grant
    Filed: June 10, 1999
    Date of Patent: December 4, 2001
    Inventors: Peter E. Toscheck, Rainer Boehm, Valerie M. Baev
  • Patent number: 6327291
    Abstract: A laser diode package couples laser diode outputs into a plurality of fibers, and these are bundled and brought to an output face that produces a divergent composite beam from the fiber ends. The beam end pumps a solid-state laser across a gap, and the divergence allows a wide tolerance in alignment of the pump and crystal. Preferably, one cavity mirror is a focusing mirror that reconcentrates residual pump light in the desired mode. In a preferred embodiment, the output face of the package is at a short stub or ferrule that provides a simple and effective pump beam centering alignment. The solid-state laser may be a rod or crystal and is preferably sufficiently short, in relation to pump beam diameter and divergence in the rod, that the pump beam within the rod lies in the TEMoo mode volume of the laser cavity. A concave mirror then refocuses residual pump light back into that mode. The rod preferably has a high index at the pump wavelength, but need not have high absorption.
    Type: Grant
    Filed: November 12, 1999
    Date of Patent: December 4, 2001
    Assignee: Iridex Corporation
    Inventor: Larry R. Marshall
  • Patent number: 6327293
    Abstract: A optically-pumped semiconductor (OPS), vertical-cavity, surface-emitting laser (VCSEL) includes a first mirror having a quantum-well structure thereon which provides a gain medium for the laser. A second mirror is spaced apart from the quantum-well structure and, together with the first mirror, forms a resonant cavity for the laser. Optical pump-radiation is directed through the gap into the quantum-well structure via an outermost layer of the quantum-well structure. The quantum-well structure includes a plurality of quantum-well layers spaced apart by pump-radiation absorbing layers. Quantum-well and pump-radiation absorbing layers are aluminum-free layers of alloys of the GaAs/InGaAsP system.
    Type: Grant
    Filed: August 12, 1998
    Date of Patent: December 4, 2001
    Assignee: Coherent, Inc.
    Inventors: Arto K. Salokatve, Juan L. A. Chilla