Patents Examined by Gioacchino Inzirillo
  • Patent number: 6181719
    Abstract: A gas laser RF power supply has two RF oscillators operating at different frequencies, the first frequency to provide maximum RF voltage to the plasma tube prior to ignition, and the second frequency to provide optimum power for sustaining CW or pulse operation of the laser. The oscillator outputs are modulated to control power to the tube, the one in the form of RF pulses at the first frequency and at a power level below the laser emission threshold, and the other in CW or pulse form at the second frequency at a laser gas medium excitation level above the laser emission threshold. The first frequency is the resonance frequency of the tube prior to plasma ignition and the frequency of minimum average RF power required for a reliable ignition. The second frequency is the most efficient operating frequency for the plasma ignited and kept ionized by the pulses of the first frequency and provides maximum output laser power.
    Type: Grant
    Filed: November 24, 1998
    Date of Patent: January 30, 2001
    Assignee: Universal Laser Systems, Inc.
    Inventors: Yefim P. Sukhman, Mikhail E. Ryskin, David W. Schultz, George M. Mavroleon
  • Patent number: 6175579
    Abstract: An apparatus and method of controlling the frequency of laser outputs are provided. The apparatus includes an optical resonator having an optical length that supports a plurality of resonant modes dependent thereon. The optical resonator includes a modulation device for modulating the optical length in response to a modulation signal. A first and second laser having a respective first and second optical output at a respective first and second laser frequencies are independently locked to different resonant modes of the optical resonator using known locking mechanisms to produce first and second laser outputs having narrow linewidths. A beatnote generator generates a beatnote signal representative of the difference between the first and second frequencies of the first and second laser outputs. A negative feedback system having a reference signal and the beatnote signal as inputs generates the modulation signal representative of a difference between the reference and beatnote signals.
    Type: Grant
    Filed: October 27, 1998
    Date of Patent: January 16, 2001
    Assignee: Precision Light L.L.C.
    Inventors: Stephen P. Sandford, Charles W. Antill, Jr.
  • Patent number: 6173001
    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: February 18, 1998
    Date of Patent: January 9, 2001
    Assignee: Massachusetts Institute of Technology
    Inventor: John J. Zayhowski
  • Patent number: 6160830
    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: March 4, 1998
    Date of Patent: December 12, 2000
    Assignee: Motorola, Inc.
    Inventors: Philip Anthony Kiely, Paul Robert Claisse, Jamal Ramdani
  • Patent number: 6160833
    Abstract: The present invention provides an independently addressable, vertical cavity surface emitting laser ("VCSEL") in the blue wavelength range of 390 to 430 nanometers. The gallium nitride-based laser structure is grown by selective area epitaxy and lateral mask overgrowth. By appropriate patterning of a dielectric mask on the gallium nitride layer on a sapphire substrate, areas in a second gallium nitride layer can have a low defect density upon which the remainder of the laser structure can be formed.
    Type: Grant
    Filed: May 6, 1998
    Date of Patent: December 12, 2000
    Assignee: Xerox Corporation
    Inventors: Philip D. Floyd, Daniel Hofstetter
  • Patent number: 6154307
    Abstract: The present invention is a method and apparatus for sequentially and repetitively diffracting multiple beams at a common predetermined angle. A coincident beam source introduces a plurality of coincident beams into an acousto-optic cell at a common location and angle, wherein each beam has a different wavelength. A signal controlling apparatus sequentially and repetitively introduces a series of signals to the acousto-optic cell. Each signal has a frequency, which corresponds to one of the multiple beams such that when the acousto-optic cell receives the signal, the acousto-optic cell operates at such frequency and diffracts the corresponding beam at the predetermined angle.
    Type: Grant
    Filed: September 18, 1998
    Date of Patent: November 28, 2000
    Assignees: United Technologies Corporation, DeMaria ElectroOptics Systems, Inc.
    Inventors: William A. Veronesi, Frederick T. Olender, Richard A. Hart
  • Patent number: 6151348
    Abstract: A semiconductor laser includes at least an active layer and a saturable absorbing layer, and a compressive strain amount in the saturable absorbing layer is set to be greater than a value of compressive strain in the active layer by about 0.3% or more. Alternatively, a semiconductor laser includes at least an active layer, a saturable absorbing layer, and a light guiding layer disposed in the vicinity of the saturable absorbing layer; and a compressive strain amount in the saturable absorbing layer is greater than a value of compressive strain in the active layer by about 0.3% or more.
    Type: Grant
    Filed: November 17, 1998
    Date of Patent: November 21, 2000
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hideto Adachi, Isao Kidoguchi, Yasuhito Kumabuchi
  • Patent number: 6151341
    Abstract: Stackable laser array elements may be configured to absorb heat effectively from laser elements, to be efficiently repaired and/or replaced, and to be effectively tested. An assembly includes readily replaceable cells having a cavity for the passage of coolant therethrough to cool the laser elements. The cells may be constructed individually for individual testing, and then stacked together and removably secured for easy replacement. The cavities of the cells form a substantially contiguous cavity through the entire assembly for the flow of coolant into and out of the assembly. The cavities of the cells include regions and surfaces which enhance the flow of coolant to regions substantially adjacent to the laser elements for the cooling thereof to provide enhanced cooling of the laser elements in the stack of cells. The flow of the coolant is oriented vertically with respect to horizontally oriented laser elements.
    Type: Grant
    Filed: May 27, 1998
    Date of Patent: November 21, 2000
    Assignee: Excel/Quantronix, Inc.
    Inventors: Douglas J. Bull, Qiang Fu
  • Patent number: 6151343
    Abstract: In a method and an apparatus for driving a diode-pumped solid-state laser, the light power emitted by the solid-state laser (1) is determined as a measurement signal, using a measurement apparatus. By comparison of the measurement signal with a predetermined light power target value, a control deviation is determined in a control amplifier the deviation being converted in a generator into a driver current for a laser diode used as a pump diode for the resonator of the solid-state laser. For the damping of high-frequency disturbances of the light power, in a high-bandwidth negative feedback branch the high-frequency components of the measurement signal are filtered out by means of a high-pass filter and are supplied to a fast control amplifier. In a control element connected in parallel to the laser diode, a portion of the driver current supplied to the laser diode is controlled dependent on the high-frequency components of the measurement signal.
    Type: Grant
    Filed: May 28, 1998
    Date of Patent: November 21, 2000
    Assignee: Heidelberger Druckmaschinen Ag
    Inventor: Heinrich Jurgensen
  • Patent number: 6144678
    Abstract: An external cavity semiconductor laser light source which comprises: an external cavity semiconductor laser light source unit; an optical filter for selecting an output beam of the external cavity semiconductor laser light source unit in a single mode; a drive unit for varying a wavelength of a transmitted light or a wavelength of a reflected light, from the optical filter; a wavelength control unit for controlling the drive unit; an optical frequency reference light source for generating a light having a reference optical frequency; an optical frequency/voltage conversion unit for generating a signal which corresponds to a difference in optical frequency between the light outputted from the optical frequency reference light source and the output beam of the external cavity semiconductor laser light source unit; a low pass filter for transmitting a low-frequency component of the signal of the optical frequency/voltage conversion unit; a switch for feeding the signal into the external cavity semiconductor ligh
    Type: Grant
    Filed: September 18, 1998
    Date of Patent: November 7, 2000
    Assignee: Ando Electric Company, Ltd.
    Inventor: Madoka Hamada
  • Patent number: 6144677
    Abstract: A relatively high average power optical laser utilizes a diode pumped multi-mode dual-clad fiber amplifier configured for double pass amplification to provide a relatively higher average power than single mode fiber amplifiers. In order to compensate for mode scrambling and depolarization from the multi-mode fiber amplifier, the output beam from the multi-mode fiber amplifier is applied to a vector phase conjugator after a single pass through the amplifier and reflected back into the amplifier. The vector phase conjugator conjugates the electric field amplitude, phase and polarization and reflects a conjugate wave back into the multi-mode fiber amplifier in a reverse direction. The propagation of the conjugate wave through the amplifier unscrambles mode mixing and restores the beam back to its original polarization state. A Faraday rotator and polarization beam splitter are used to outcouple an output beam after the second pass through the multi-mode fiber amplifier.
    Type: Grant
    Filed: August 11, 1998
    Date of Patent: November 7, 2000
    Assignee: TRW Inc.
    Inventors: Hiroshi Komine, William H. Long, Jr.
  • Patent number: 6141402
    Abstract: The present invention, in one form, is a system which, in one embodiment, utilizes signals from a detector array to verify system dose. More specifically, the detector array signal intensities are used to determine image noise and a collimator aperture to verify an x-ray dosage. Particularly, in one embodiment, the signals intensities from the detector array are used to determine the position of collimator cams. Using the position of the collimator cams, the aperture of the collimator is determined so that X-ray dose may verified using the collimator aperture and image noise information.
    Type: Grant
    Filed: August 25, 1998
    Date of Patent: October 31, 2000
    Assignee: General Electric Company
    Inventor: Thomas L. Toth
  • Patent number: 6141367
    Abstract: A solid state dye laser is adapted for use in a solid state dye laser assembly having a pump adapted to emit light at a first frequency and intensity. The solid state dye laser includes an elongated web of polymeric host material having a gain medium disposed therein, the gain medium being in a substantially solid state and doped with a fluorescent dye adapted to emit light within a predetermined spectral tuning range. The gain medium includes polymeric cholesteric liquid crystal disposed in a planar texture and frozen into a characteristic wavelength. The solid state dye laser, including the gain medium, is adapted for convenient movement relative to the pump.
    Type: Grant
    Filed: March 20, 1998
    Date of Patent: October 31, 2000
    Assignee: Reveo, Inc.
    Inventors: Bunsen Fan, Sadeg Mustafa Faris
  • Patent number: 6137817
    Abstract: A novel quantum cascade (QC) laser comprises a multiplicity of identical repeat units, with each repeat unit comprising an active region and an injector region. The injector region comprises quantum wells and barriers, selected to facilitate, under appropriate bias, resonant carrier transport from a lower energy level of a given active region to an upper energy level of an adjacent downstream active region. Carrier transition from the upper energy level to a lower energy level of an active region results in emission of infrared radiation. The laser is advantageously used in, e.g., a measurement system for detection of trace compounds in air.
    Type: Grant
    Filed: June 12, 1998
    Date of Patent: October 24, 2000
    Assignee: Lucent Technologies Inc.
    Inventors: James Nelson Baillargeon, Federico Capasso, Alfred Yi Cho, Claire F. Gmachl, Albert Lee Hutchinson, Deborah Lee Sivco, Alessandro Tredicucci
  • Patent number: 6130902
    Abstract: A laser amplification system includes a pumping diode laser, a gain laser crystal, a moveable wedged shaped etalon for wavelength selection, a non-linear crystal for wavelength conversion, such that each optical component has independent temperature control means. A single mode operation is achieved of up to 100 Watts output power with a minimum noise by stabilizing the optimum temperature of the optical media and the optical pathlength of the etalon. All components are disposed on a single metal substrate having a high thermal conductivity and a low thermal expansion coefficient. The system operates to amplify a laser from another source with high efficiency and low noise when the etalon and nonlinear crystal are absent.
    Type: Grant
    Filed: May 26, 1998
    Date of Patent: October 10, 2000
    Inventor: Yutaka Shimoji
  • Patent number: 6118804
    Abstract: A laser amplification system with a lasant solid-state material is pumped by pumped light sources and in the case of which one or several pumped beams are guided by mirrors or other optical aids such that each individual pumped beam is focussed several times on different points of the solid-state material, the latter being present in the form of a cohesive or separate solid body which is designed such that the pumped beam is absorbed only in the focal regions, whereby the latter are optically pumped, and in that the laser beam is deflected and guided such that it irradiates all these focal points and is amplified in this manner. This provides a laser amplification system in which the system characteristics are optimized simultaneously, which, in addition, permits a compact construction and is designed such that it is suitable for mass production at reasonable cost.
    Type: Grant
    Filed: May 4, 1998
    Date of Patent: September 12, 2000
    Assignees: DaimlerChrysler AG, Micro Systems Design Dr. Altmann GmbH
    Inventors: Konrad Altmann, Thorsteinn Halldorsson
  • Patent number: 6111906
    Abstract: A stable single-mode oscillation semiconductor laser is obtained by flattening the distribution of electric field intensity in the direction of the resonator axis, and to provide a distributed-feedback semiconductor laser generator having a more satisfactory difference in threshold gain between the principal and subsidiary modes. The laser includes an active layer which radiates light as a result of the injection of electrons, a light guide layer which is next to this active layer guides light emitted from the active layer, a plurality of semiconductor layers between which the active layer and light guide layer are interposed, electrodes which permit electrons to be injected from these semiconductor layers into the active layer, a non-reflective coating provided on both ends of the active layer in the direction of oscillation, and a diffraction grating which is provided on the light guide layer for selecting the oscillatory wavelength of the light.
    Type: Grant
    Filed: March 16, 1998
    Date of Patent: August 29, 2000
    Assignee: NEC Corporation
    Inventor: Yoshiharu Muroya
  • Patent number: 6104734
    Abstract: In order to eliminate noise of a solid state laser apparatus generating a blue light wave, the solid state laser apparatus comprises a solid state laser light source, an optical modulator having a light modulating function and outputting the modulated light therefrom as a desired light output, a photo-detector converting one part of output light from the solid state laser light source to an electrical signal, an electrical circuit detecting a noise component from the electrical signal and moving the phase of an electrical signal corresponding to the noise component, and a controller for applying the output signal of the electrical circuit to the optical modulator so as to substantially eliminate light of the blue light wave corresponding to the noise component so as to provide the desired light output from the optical modulator.
    Type: Grant
    Filed: June 3, 1999
    Date of Patent: August 15, 2000
    Assignees: Hitachi, Ltd., Hitachi Metals, Ltd.
    Inventors: Tadao Ino, Hirofumi Sukeda, Hideki Saga, Hiroshi Toyama, Tsuyoshi Miyai
  • Patent number: 6097748
    Abstract: A vertical cavity surface emitting laser semiconductor chip including a vertical cavity surface emitting laser (VCSEL) formed on a substrate, a photodetector, integrated with the vertical cavity surface emitting laser for automatic power control (APC) of the vertical cavity surface emitting laser and a driver circuit, integrated with the vertical cavity surface emitting laser and the photodetector. The VCSEL, photodetector and driver circuit are integrated by utilizing a monolithic polysilicon layer. The driver circuit is characterized as a CMOS driver circuit, capable of receiving feedback from the photodetector and adjusting the output power of the vertical cavity surface emitting laser in response to the feedback, thus achieving APC of the VCSEL.
    Type: Grant
    Filed: May 18, 1998
    Date of Patent: August 1, 2000
    Assignee: Motorola, Inc.
    Inventors: Rong-Ting Huang, Chan-Long Shieh, Michael S. Lebby
  • Patent number: 6097745
    Abstract: The heat generated by a laser oscillator is partly radiated toward a frame. The radiated heat is partly absorbed by a cooling mechanism. The remaining heat is transferred through a chamber which dissipates part of the heat, to a heat insulating panel, which blocks most of the heat. The heat generated by the laser oscillator is partly radiated outwardly and reflected by a casing inwardly toward the frame. The reflected heat is partly absorbed by cooling mechanisms. The remaining heat is transferred through chambers which dissipate part of the heat, to the heat insulating panel, which blocks most of the heat. Therefore, any temperature rise of the frame due to the heat generated by the laser oscillator is very small, and the frame is prevented from being deformed due to the heat from the laser oscillator. Because the frame is not deformed, a laser beam emitted from the laser oscillator is applied to a desired position which remains unchanged.
    Type: Grant
    Filed: July 7, 1998
    Date of Patent: August 1, 2000
    Assignee: Honda Giken Kogyo Kabushiki Kaisha
    Inventors: Noriaki Shigematsu, Kazuhide Matsuo, Isao Bundo