Patents Examined by Xuan T. Vo
  • Patent number: 4856013
    Abstract: A laser has an active layer formed on a prepared substrate, a cladding layer on the active layer and a contact layer on the cladding layer. The active layer and contact layer are formed of a semiconductor material of elements from Groups III-V. The contact layer and cladding layer are formed into an elongated projecting rib wherein the cladding layer has a remaining planar portion disposed across the active layer. An insulating layer of semiconductor of elements from Group II-VI is formed on each side of the rib supported on the remaining cladding layer.
    Type: Grant
    Filed: October 28, 1987
    Date of Patent: August 8, 1989
    Assignee: Seiko Epson Corporation
    Inventors: Hideaki Iwano, Yoshifumi Tsunekawa
  • Patent number: 4841530
    Abstract: A broadly wavelength-tunable laser is provided which comprises as the laser medium a single crystal of MBO.sub.3 :Cr.sup.3+, where M is selected from the group of Sc, In and Lu. The laser may be operated over a broad temperature range from cryogenic temperatures to elevated temperatures. Emission is in a spectral range from red to infrared, and the laser is useful in the fields of defense, communications, isotope separation, photochemistry, etc.
    Type: Grant
    Filed: March 27, 1986
    Date of Patent: June 20, 1989
    Assignee: Allied-Signal Inc.
    Inventors: Bruce H. Chai, Shui T. Lai, Margaret N. Long
  • Patent number: 4841529
    Abstract: A system for generating a stable optical frequency from a laser signal having inherent frequency fluctuations. The signal from an injection-controlled pulsed laser is divided into two parts. One part is mixed with the signal from a stable CW laser to generate beat frequencies. These signals are amplified and recombined with the pulsed laser signal in an output modulator. In one embodiment, the difference frequency between the pulsed laser and the reference signal is less than 1000 MHz. The beat frequencies are increased by an X-band mixer to the microwave range where they can be readily amplified in an available broad band amplifier. In another embodiment, the transmitter laser and the reference laser operate at a difference frequency in the microwave range, say, above 5,000 MHz. The beat frequencies are obtained by a high frequency mixer such as a bulk crystal in a waveguide or cavity. In still another embodiment, two independent transmitter lasers generate pulses that occur with a significant time delay.
    Type: Grant
    Filed: September 9, 1987
    Date of Patent: June 20, 1989
    Assignee: Laser Science, Inc.
    Inventor: Ali Javan
  • Patent number: 4837775
    Abstract: A distributed feedback laser comprising a semiconductor body having a channel which varies in width in the laterial direction and is periodic in the longitudinal direction. When the laser is electrically excited constructive interference of reflected light gives rise to a stable single wavelength output due to the periodic variations in the channel.
    Type: Grant
    Filed: November 2, 1987
    Date of Patent: June 6, 1989
    Assignee: General Electric Company
    Inventors: James T. Andrews, Ivan Ladany
  • Patent number: 4829537
    Abstract: A nonstandard spherical resonator which produces laser radiation having spherical modes of oscillation is formed entirely within a sphere of laser gain material. The resonator is pumped to produce the spherical modes. By pumping an isotropically coated sphere at normal incidence the entire sphere forms the resonator, and the laser radiates uniformly in all directions as from a point source. By pumping obliquely to totally internally reflect the laser radiation at the surface of the sphere, or by applying an equatorial coating on the sphere to internally reflect the laser radiation, toroidal region within the sphere forms the resonator. The pumping volume can be controlled so that the laser radiation is single longitudinal mode and single frequency by limiting the active mode volume. Prisms can be used for input and output coupling to the toroidal resonator; and optical fiber can also be used for output coupling. A compact laser design uses a Nd:YAG sphere pumped by a laser diode.
    Type: Grant
    Filed: December 1, 1986
    Date of Patent: May 9, 1989
    Assignee: Spectra-Physics, Inc.
    Inventor: Thomas M. Baer
  • Patent number: 4823354
    Abstract: In an excimer laser system with wavelength bandwidth narrowing, a feedback loop for monitoring and correcting the tuning of the laser employs a wavelength calibration device in the form of a gas with an absorption peak at the desired narrow wavelength. A portion of the laser output received through the gas provides the information for generating the correction signal.
    Type: Grant
    Filed: December 15, 1987
    Date of Patent: April 18, 1989
    Assignee: Lumonics Inc.
    Inventors: Thomas A. Znotins, John Reid, Steven J. Gutz
  • Patent number: 4821281
    Abstract: A ring laser angular rate sensor construction utilizes an anode-cathode configuration which generates a glow discharge region in the propagation path of the laser beams. The anode-cathode construction provides a hollow cathode and effect for a ring laser. Specifically the ring laser block incorporates a tubular cavity which forms in part a cathode. A slot is provided into the block to provide an electrically insulated anode to produce the hollow cathode effect and the generation of counter-propagating laser beams.
    Type: Grant
    Filed: September 15, 1986
    Date of Patent: April 11, 1989
    Assignee: Honeywell Inc.
    Inventors: Bruce J. Lind, Hendrik J. Oskam
  • Patent number: 4818057
    Abstract: A plug housing for receiving an optical fiber cable having independent arrangements for gripping the jacket of the cable, wrapping and gripping the reinforcement elements of the cable, and for gripping the optical fibers of the cable, each of these arrangements is independently mounted within the housing so that each can be separately manipulated. In addition, these arrangements are each received in the housing without deforming a portion of the housing.
    Type: Grant
    Filed: November 12, 1987
    Date of Patent: April 4, 1989
    Assignee: Siemens Aktiengesellschaft
    Inventor: Helmut Bruch
  • Patent number: 4819244
    Abstract: A V-channel inner stripe semiconductor laser device comprising a multi-layered growth crystal having an active layer for laser oscillation but no substrate, with a buffer layer formed on the multi-layered growth crystal thicker than all of the layers of the growth crystal, where the multi-layered growth crystal and buffer layer are sandwiched between an n-sided electrode and a p-sided electrode, wherein a pair of mesa-striped channels are formed outside of the V-channel to remove the outside of the optical waveguide formed in the active layer corresponding to the V-channel.
    Type: Grant
    Filed: June 4, 1986
    Date of Patent: April 4, 1989
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Saburo Yamamoto, Hiroshi Hayashi, Taiji Morimoto
  • Patent number: 4817101
    Abstract: A heterodyne laser spectroscopy system utilizes laser heterodyne techniques for purposes of laser isotope separation spectroscopy, vapor diagnostics, processing of precise laser frequency offsets from a reference frequency and the like, and provides spectral analysis of a laser beam.
    Type: Grant
    Filed: September 26, 1986
    Date of Patent: March 28, 1989
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: Richard W. Wyeth, Jeffrey A. Paisner, Thomas Story
  • Patent number: 4807237
    Abstract: In a laser oscillator or laser amplifier, a so-called switching dye is used which strongly reduces the degree of amplification for the laser radiation after a short time interval, by means of transient absorption. Molecules or molecule systems in which a proton transfer takes place in the excited state can serve as switching dyes. The radiation pulse exciting the switching dye must have a sufficiently steep leading flank to assure that the excited state of the tautomeric form is rapidly occupied. The immediately following occupation of the ground state of the tautomeric form by emission of radiation and radiationless transitions, and/or of triplet states of the tautomeric and normal form by radiationless transitions, builds up a transient absorption and inhibits the rise of an inversion sufficient for renewed radiation emission.
    Type: Grant
    Filed: July 18, 1986
    Date of Patent: February 21, 1989
    Assignee: Max-Planck -Gesellschaft zur Forderung der Wissenschaften e.V.
    Inventor: Nikolaus Ernsting
  • Patent number: 4807241
    Abstract: The luminescent screen of a cathode ray tube includes an array of monocrystalline or amorphous phosphor rod-like elements which are covered with a reflective coating except for one end of each element which serves as an output face. The phenomenon of the light trapping is advantageously exploited to achieve enhanced brightness. The screen is illuminated with an electron beam which has an essentially oblong cross section and which is oriented along the elongated dimension of the elements. In one embodiment the elements comprise epitaxial Lu.sub.3 Al.sub.3 Ga.sub.2 O.sub.12 :Ce on the top of a YAG substrate, and a light absorbing layer of Lu.sub.3 Al.sub.3.5 Fe.sub.1.5 O.sub.12 is formed on the bottom of the substrate. A printer utilizing such a CRT is described. Also described is a configuration in which each of the rod-like elements functions as a laser.
    Type: Grant
    Filed: July 10, 1987
    Date of Patent: February 21, 1989
    Assignee: American Telephone and Telegraph Company AT&T Bell Laboratories
    Inventors: George W. Berkstresser, Joseph Shmulovich
  • Patent number: 4797889
    Abstract: A solid state laser in which molecules containing transition metal ions form the lasing medium. More particularly, the electronic states of molecular complexes containing transition metal ions, which are in closed shell configurations, are pumped by an ultraviolet source to emit coherent radiation.
    Type: Grant
    Filed: June 24, 1987
    Date of Patent: January 10, 1989
    Assignee: Boston University
    Inventor: Alexander Lempicki
  • Patent number: 4797893
    Abstract: A microlaser comprises a solid state gain medium, such as YLF or YAG, positioned end to end with a mode selector etalon formed by a fused silica flat, the end of which is adjacent to a planar end of the gain medium is coated with a thin film of nichrome and the other end of which is coated with a multilayer-dielectric partially-transmissive reflector. The other end of the gain medium is curved and coated to be reflective of the laser light and transmissive of the pump light which enters through such end. The thin nichrome film is designed to absorb unwanted modes which have an electric field component at such film while a wanted mode has a null at such film in their standing wave patterns. By substituting birefringent crystalline quartz for the fused-silica, there may be derived emission at two longitudinal modes whose polarization vectors are orthogonal and whose wavelengths are slightly different.
    Type: Grant
    Filed: June 9, 1987
    Date of Patent: January 10, 1989
    Assignee: Virgo Optics, Inc.
    Inventor: George J. Dixon
  • Patent number: 4794607
    Abstract: An optical amplifier takes the form of a semiconductor laser with coatings on its two facets. The coating takes the form of an anti-reflective coating, e.g. an oxide of Y, Gd, Nd, or La, to reduce the reflectivity and a thin interlayer, e.g. Al.sub.2 O.sub.3, to enhance compatibility between the laser and the anti-reflective coating.
    Type: Grant
    Filed: June 2, 1986
    Date of Patent: December 27, 1988
    Assignee: British Telecommunications public limited company
    Inventor: William J. Devlin
  • Patent number: 4791637
    Abstract: A gas laser generator comprises a frame, a gas channel through which a gas flows, a mirror for obtaining a laser beam, defining a resonant cavity, an anode electrode and at least two first and at least two second cathode electrodes arranged in the lower and the upper portions of the resonant cavity, respectively, and a power source, in which a first voltage of a first electric field between the first cathode electrodes connected to the power source through a first ballast resistance and the anode electrode and a second voltage of a second electric field between the second cathode electrodes connected to the power source through a second ballast resistance and the anode electrode are so determined that the former is smaller than the latter so that the current flowing in the first electric field may be substantially equal to the current flowing in the second electric field during the electric discharges between the electrodes.
    Type: Grant
    Filed: February 25, 1987
    Date of Patent: December 13, 1988
    Assignee: Amada Company, Limited
    Inventor: Masao Kimura
  • Patent number: 4791649
    Abstract: A multilayered crystal structure in a semiconductor laser device contains an active layer for laser oscillation on a V-stripe channeled substrate having a current-blocking layer thereon. The active layer further includes regions by means of which carriers within the active layer are prevented from diffusing outside of the active layer. These regions are disposed facing each other with an optical waveguide therebetween which is formed by the absorption of light by the portions of the current-blocking layer which are positioned at both sides of the striped channel. The distance between the regions is narrower than the width of the optical waveguide in the vicinity of both facets and wider than the width of the optical waveguide inside of both facets.
    Type: Grant
    Filed: July 15, 1986
    Date of Patent: December 13, 1988
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Saburo Yamamoto, Taiji Morimoto, Noboyuki Miyauchi, Shigeki Maei
  • Patent number: 4782495
    Abstract: Two different reflector designs for use in an optically pumped, fluid cooled slab laser are disclosed. Each reflector design is effective to introduce a positive focal power lens effect into a central portion of the lasing medium width that is approximately equal in magnitude to a negative lens effect experienced in lateral edge portions of the lasing medium.
    Type: Grant
    Filed: December 21, 1987
    Date of Patent: November 1, 1988
    Assignee: General Electric Company
    Inventor: Farzin H. Azad
  • Patent number: 4779286
    Abstract: A laser optical cavity extends between two end reflectors (11, 12) and is defined by at least three sections. A number of folding reflectors (14) are provided for directing radiation emerging from one section into the next. An active medium is contained in the sections and excitation means are provided to produce laser action. A rigid support member (10) supports the end reflectors (11, 12) and the folding reflectors (14) around a generally cylindrical surface such that a continuous optical path extends between the end reflectors (11, 12) by way of each folding reflector (14) in turn. At least three of the laser sections extend across a substantial part of the area with the cylinder (10) and each section crosses at least one other section at or near to the axis of said cylinder as viewed along that axis.
    Type: Grant
    Filed: June 25, 1987
    Date of Patent: October 18, 1988
    Assignee: Ferranti plc
    Inventor: David I. Wheatley
  • Patent number: 4779278
    Abstract: Disclosed is a laser apparatus and a related method for use with a laser medium of a type which emits a beam of coherent laser energy having both low and high order modes. End reflectors are provided for reflecting at least a portion of the energy in the beam back through the laser medium, and positive and negative lens elements are positioned on opposing sides of the lasing medium so that discrimination against the higher order modes is achieved by non-linearly amplifying the reflected beam portion passing through the lasing medium.
    Type: Grant
    Filed: December 5, 1986
    Date of Patent: October 18, 1988
    Assignee: Laser Photonics, Inc.
    Inventor: Robert E. McKinney