Patents Examined by Rodney B. Bovernick
  • Patent number: 5859864
    Abstract: An improved semiconductor structure is provided. The semiconductor structure comprises a first layer, the first layer having a restricted growth surface having a region with a transverse dimension D, the first layer having a first lattice constant L.sub.1 ; a first, last and at least one intermediate transition layers, the transition layers forming a transition region, the transition region disposed above the first layer, the transition region having a vertical thickness T, and where at least one of the transition layers has lattice constants between L.sub.1 and a second lattice constant L.sub.2 where the first transition layer has a lattice constant closer to the L.sub.1 than L.sub.2 and the last transition layer has a lattice constant closer to the L.sub.2 than L.sub.1 ; and a second layer disposed on the transition region, the second layer having the second lattice constant L.sub.2 ; wherein: the transition region has an average fractional change in lattice constant characterized by .kappa. where .kappa.
    Type: Grant
    Filed: October 28, 1996
    Date of Patent: January 12, 1999
    Assignee: Picolight Incorporated
    Inventor: Jack L. Jewell
  • Patent number: 5859866
    Abstract: A monolithically integrated vertical twin-waveguide structure reduces the sensitivity of the device performance characteristics due to the laser cavity length and variations in the layer structure. This is achieved by the introduction of an absorption or loss layer between the active and passive regions. This layer eliminates the propagation of the even mode, while having minimal effect on the odd mode. The threshold current densities and differential efficiencies of the devices are unaffected by the loss layer. A coupling efficiency of 45% from the laser to the external passive waveguide is obtained.
    Type: Grant
    Filed: February 7, 1997
    Date of Patent: January 12, 1999
    Assignee: The Trustees of Princeton University
    Inventors: Stephen Forrest, Chih-Ping Chao, Miland Gokhale, Ligeng Xu
  • Patent number: 5859862
    Abstract: An optical recording/reproducing apparatus has a laser diode and a semiconductor integrated circuit device for driving the laser diode. The semiconductor integrated circuit device has a driver circuit for producing a drive current to be supplied to a laser diode in accordance with an input signal representative of a laser beam power varying depending on a relative speed between a magneto-optical disk and a spot of a laser beam emitted by the laser diode on the optical disk. The driver circuit has a non-linear first operation range and a substantially linear second operation range subsequent to the first operation range. For a linear operation of the driver circuit, a level shifter circuit is connected to the driver circuit for applying a shift voltage to the driver circuit with a result that an excess output current is produced by the driver circuit even when the input signal is non-existent.
    Type: Grant
    Filed: June 20, 1995
    Date of Patent: January 12, 1999
    Assignee: Hitachi, Ltd.
    Inventors: Kazuhiko Hikasa, Tadashi Oka
  • Patent number: 5852625
    Abstract: The gain coupled distributed feedback semiconductor laser includes an active layer and a diffraction grating which is provided in the vicinity of the active layer and has a plurality of light absorption layer periodically arranged along a resonator length direction. A relationship among energy h.nu. (h is Planck's constant, and .nu. is a frequency of induced emission light), forbidden band width E.sub.g of the light absorption layer, and energy band width .delta.E where free electrons are thermally distributed satisfies h.nu..gtoreq.E.sub.g +.delta.E.
    Type: Grant
    Filed: March 22, 1996
    Date of Patent: December 22, 1998
    Inventor: Koji Takahashi
  • Patent number: 5850412
    Abstract: The present invention relates to a laser generator in which a laser beam is generated by energizing a laser medium and is amplified optically with optically amplifying mirrors, and the laser beam is received by a absorber, wherein a spacer 9 having a through hole 9a for passing therethrough the laser beam and at least one small second through hole 9b is arranged at a circumference of an absorber 7, and a cooling medium 12 circulates in the small second through hole 9b of the spacer 9. In this structure, if a scattering laser beam is generated at the circumference of the laser beam absorber, a parallelism of the optical amplifying mirrors is maintained so that the laser generator can generate the stable laser beam.
    Type: Grant
    Filed: December 20, 1996
    Date of Patent: December 15, 1998
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Satoshi Eguchi, Takayuki Yamashita, Hiroyuki Hayashikawa
  • Patent number: 5848088
    Abstract: A surface emission type semiconductor laser having an optical detector which can satisfactorily assure both the laser emission characteristics of the photoemitter and the optical-to-electrical conversion efficiency. The laser comprises a first conducting semiconductor layer and a second conducting semiconductor layer formed on first and second regions of a semiconductor substrate. Over the second conducting semiconductor layer on the first region is formed an optical resonator which emits light perpendicular to the plane of the semiconductor substrate. On the second region, at least one photodiode is formed by the first and second conducting semiconductor layers. On the first region the second conducting semiconductor layer is formed with a thickness of at least 1 .mu.m, and is used as a lower electrode for supplying a current to the optical resonator. On the second region, the second conducting semiconductor layer forming the at least one photodiode is formed with a thickness of less than 1 .mu.
    Type: Grant
    Filed: November 26, 1997
    Date of Patent: December 8, 1998
    Assignee: Seiko Epson Corporation
    Inventors: Katsumi Mori, Takayuki Kondo, Takeo Kaneko
  • Patent number: 5848082
    Abstract: A heatsink and an optical system are provided for use in conjunction with a dissipating semiconductor or electronic device, such as a light source, that generate a large amount of heat and is required to be cooled for optimum performance. The light source may be a laser diode or laser array or bar and is generally mounted on the heatsink with other optical components, such as collimating and focusing lenses, isolators or terminal ends of optical fibers, for coupling the output beam of the light source in aligned relation to these optical elements. Because of the higher temperature operation of such light sources, the heat generated causes thermal expansion of mechanically connected structures, such as between the heatsink for supporting the light source and its associated submount and an underlying support, usually a cooler.
    Type: Grant
    Filed: August 11, 1995
    Date of Patent: December 8, 1998
    Assignee: SDL, Inc.
    Inventor: Frank T. C. Shum
  • Patent number: 5848204
    Abstract: New sensing and diagnostic methods are implemented with multimode fiber Bragg gratings (MMFBG) and methods for sensor addressing and multiplexing are described. Real time structural strain and vibration monitoring using optical time domain reflectometry (OTDR) is discussed. The first all-mode, wave optics calculations of the reflectivity of Bragg gratings in highly multimode optical fibers are presented, including the effects of individual mode power changes due to microbending transducer loss upstream from the grating. Two categories of multimode fiber gratings are possible, independent mode and mode coupling, and the fabrication differences between these types of gratings are described. The reflectivity properties of independent mode multimode fiber gratings are examined and compared to single mode fiber gratings.
    Type: Grant
    Filed: September 8, 1995
    Date of Patent: December 8, 1998
    Assignee: California State University-Fullerton
    Inventor: Keith H. Wanser
  • Patent number: 5844931
    Abstract: A semiconductor laser which does not cause a sudden failure due to an electric surge. A ridge that is formed by a GaAs buffer layer, an n-InGaP cladding layer which is lattice-matched to a GaAs substrate, a strained-quantum well active layer, a p-InGaP cladding layer which is lattice-matched to the GaAs substrate, a p-GaAs waveguide layer, a p-InGaP cladding layer which is lattice-matched to the GaAs substrate, and a p-GaAs cap layer is constructed on the n-GaAs substrate by being buried therein by an n-InGaP current-blocking layer. A device stripe is constructed by a current-injected region in the device and current-non-injected regions near facets.
    Type: Grant
    Filed: July 31, 1997
    Date of Patent: December 1, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Misuzu Sagawa, Kiyohisa Hiramoto, Tomonobu Tsuchiya, Takashi Toyonaka, Kazunori Shinoda
  • Patent number: 5844927
    Abstract: An optical end-pumped fiber laser doped with one or more rare-earths and with distributed feedback (DFB) via a fiber Bragg-grating, which is oscillating on two orthogonally polarized wavelengths. The distance between the wavelengths may be tuned by changing the birefringence of the fiber. The laser may be applied as a polarimetric sensor in which an asymmetrical force changes the wavelength separation, or as a tunable two-wavelength source. A particular preferred field of application is for measuring the pressure in pipes, to determine the flow.
    Type: Grant
    Filed: March 20, 1996
    Date of Patent: December 1, 1998
    Assignee: Optoplan AS
    Inventor: Jon Thomas Kringlebotn
  • Patent number: 5841927
    Abstract: A crystal substrate, with an adhesive uniformly applied to its entire rear surface, is fixed to the inner wall of an element housing. By adjusting the thickness of a wall of the element housing, forming grooves in the wall, or fixedly attaching a deadweight to the wall, the resonant frequency of the element housing is adjusted so as to restrain the optical waveguide element from resonating. Further, by mounting the optical waveguide device on a printed board via an elastic member or the like, propagation of the vibration to it is suppressed.
    Type: Grant
    Filed: September 16, 1994
    Date of Patent: November 24, 1998
    Assignee: Fujitsu Limited
    Inventors: Junko Watanabe, Hironao Hakogi, Akiko Tanno, Toshihiro Otani, Shinya Sawae
  • Patent number: 5841797
    Abstract: Apparatus for stabilizing multiple laser sources having distinguishable optical characteristics, e.g., in polarization field or operational wavelength, comprises a plurality of semiconductor laser sources having respective lasing cavities capable of lasing within a narrow bandwidth of wavelengths and providing spectral outputs at their respective laser exit facets having different optical characteristics from one another. The spectral output beams of the sources may be coupled to respective optical fibers and the beams combined via a beam combiner, e.g., a polarizing beam combiner or a WDM combiner. The beam combiner combines the beam outputs forming a single beam which is launched into an output optical fiber. At least one feedback fiber grating is provided in at least one of the optical fibers with the number thereof depending upon distinguishable optical characteristics of the multiple laser sources.
    Type: Grant
    Filed: December 24, 1996
    Date of Patent: November 24, 1998
    Inventors: Brian F. Ventrudo, Peter G. Berrang
  • Patent number: 5841800
    Abstract: A desktop medical laser generator (10) for laser surgery has a base plate (12) and an optical assembly (14) mounted thereon. The optical assembly (14) has an improved lamp housing (16) having two identical shell sections (44) and associated components for housing a YAG rod (60) and a lamp (58). Light emitted from the lamp housing (16) is doubled in frequency by a KTP crystal (26), monitored by two power detectors (32,34) and emitted through an output connector (36). A line power control system (90) insures the current drawn from a standard wall receptacle (80) does not exceed accepted limits. An output power detection system (90) closely monitors output power.
    Type: Grant
    Filed: July 28, 1995
    Date of Patent: November 24, 1998
    Assignee: Laserscope
    Inventors: Scott A. Davenport, Michael Hodel
  • Patent number: 5838712
    Abstract: A diode-pumped high performance solid state laser has at least one pump module comprising at least two laser diode arrays which transversely irradiate a solid state laser rod. The path length of the radiation emitted by a laser diode array through the solid state laser rod and the required absorption path for this radiation, determined by the emission wavelength of this radiation and the doping of the laser-active medium, are adapted to one another extensively in different ways.
    Type: Grant
    Filed: December 18, 1996
    Date of Patent: November 17, 1998
    Assignee: JENOPTIK Aktiengesellschaft
    Inventors: Juergen Kraenert, Holger Kuehn, Holger Mueller, Siegfried Kufert
  • Patent number: 5838704
    Abstract: A pulsation laser includes an n-type AlGaAs cladding layer on an n-type GaAs substrate, three quantum well active layers having central increased thickness regions and disposed on the cladding layer, and a p-type AlGaAs cladding layer disposed on the quantum well active layer. The increased thickness region of the active layer is not more than one-quarter of the length of the resonator of the laser.
    Type: Grant
    Filed: May 17, 1996
    Date of Patent: November 17, 1998
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yutaka Mihashi, Motoharu Miyashita, Shoichi Karakida
  • Patent number: 5838715
    Abstract: A VCSEL 101 comprising an optical cavity having an optical loss and a loss-determining element 117 coupled to the optical cavity. The loss-determining element 117 progressively increases the optical loss of the optical cavity with increasing lateral distance from the optical axis 105. The optical cavity includes a first mirror region 111, a second mirror region 107, a plane light-generating region 125 sandwiched between the first mirror region 111 and the second mirror region 107, perpendicular to the optical axis 105, and an element 113 that defines the lateral extent of the optical cavity in the plane of the light-generating region 125. The first mirror region 111 and the second mirror region 107 are both conductive and have opposite conductivity modes.
    Type: Grant
    Filed: June 20, 1996
    Date of Patent: November 17, 1998
    Assignee: Hewlett-Packard Company
    Inventors: Scott W. Corzine, Dubravko I. Babic, Richard P. Schneider, Jr., Michael R. Tan, Shih-Yuan Wang
  • Patent number: 5838705
    Abstract: A first stack (112) of distributed Bragg reflectors, a first cladding region (114) disposed on the first stack of distributed Bragg reflectors (112) and including a defect inhibition layer (117) an active area (122) disposed on the first cladding region (114), a second cladding region (132) disposed on the active area (122) and including a defective inhibition layer (136), and a second stack (140) of distributed Bragg reflectors disposed on the second cladding region (132). The defect inhibition layers (117, 136) substantially prevent defects in the active area (122).
    Type: Grant
    Filed: November 4, 1996
    Date of Patent: November 17, 1998
    Assignee: Motorola, Inc.
    Inventors: Chang-Long Shieh, Wenbin Jiang, Paul Claisse, Craig A. Gaw
  • Patent number: 5838714
    Abstract: A wavelength tunable laser emission component includes on the same substrate an active emission section and a Bragg section that includes a waveguide in which is formed a plurality of individual Bragg gratings corresponding to particular Bragg wavelengths. The waveguide has an electro-absorbent structure, the subsections of the Bragg section each being voltage-controlled. The laser emission wavelength is tuned to one or other of the Bragg wavelengths of these subsections according to control voltages applied thereto.
    Type: Grant
    Filed: August 15, 1996
    Date of Patent: November 17, 1998
    Assignee: France Telecom
    Inventor: Franck Delorme
  • Patent number: 5838850
    Abstract: A method and apparatus for curved-angle cleaving of optical fibers is presented. The method requires the introduction of a flaw in an optical fiber to be cleaved, and the application of predetermined stress and strain to the optical fiber in the vicinity of the flaw to cause curved-angle cleaving of the optical fiber at the flaw. More particularly, one embodiment of the method requires fixing first and second portions of the optical fiber, for example, by clamping, and introducing a flaw into the optical fiber between the first and second portions. Then, a substantially concentrated force is applied to the optical fiber between the flaw and the first portion of the optical fiber, on a side of the optical fiber opposite the flaw, in order to cause the optical fiber to cleave with a curved-angle cleave. Another embodiment of the method applies a substantially concentrated force to the fiber before introduction of the flaw.
    Type: Grant
    Filed: March 19, 1997
    Date of Patent: November 17, 1998
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Charles M. Mansfield, Gordon Wiegand
  • Patent number: 5835514
    Abstract: An integrated laser-based light source that generates an output light beam having a controlled intensity. The light source comprises a light sensor, a laser, a convex beam-splitting surface, and a package that includes a header. The light sensor generates an electrical signal representing an intensity of light energy falling on it, and is mounted on the header. The laser has one and only one light-emitting face from which a light beam is radiated as a radiated light beam. The laser is mounted in the package adjacent the light sensor with the light-emitting face substantially parallel to the light-receiving face of the light sensor. The convex beam-splitting surface reflects a fraction of the radiated light beam towards the light sensor as a reflected light beam, and transmits the remainder of the radiated light beam as the output light beam. The convex beam-splitting surface is supported in the radiated light beam by the package.
    Type: Grant
    Filed: January 25, 1996
    Date of Patent: November 10, 1998
    Assignee: Hewlett-Packard Company
    Inventors: Albert T. Yuen, Tao Zhang, David M. Sears, Leif Eric Larson