Patents Examined by Yisun Song
  • Patent number: 5841802
    Abstract: An electron beam pumped semiconductor laser which includes a substrate, an optical gain structure provided on the substrate, the optical gain structure being comprised of a plurality of alternating quantum well layers and isolation layers, the quantum well layers being spaced apart from one another by respective, intervening ones of the isolation layers by a sufficient distance to substantially isolate the quantum well layers from one another, and a first reflective layer provided on a first surface of the optical gain structure. With this construction, the quantum well layers are quantum mechanically uncoupled. Further, the optical gain structure has a total thickness which is sufficient to enable the optical gain structure to be coupled to excitation of an electron beam produced by an electron beam pumping device and directed through the first reflective layer and incident upon the optical gain structure.
    Type: Grant
    Filed: August 30, 1996
    Date of Patent: November 24, 1998
    Assignee: McDonnell Douglas Corporation
    Inventors: J. Stanley Whiteley, Neil F. Ruggieri, Robert R. Rice
  • 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: 5838708
    Abstract: The present invention provides a structure and method for integrating a photodiode and surface emitting laser on a substrate which minimizes both process complexity and exposure of epitaxial layers. In a first embodiment, a photodiode structure is integrated with the surface emitting laser simply by adding a separate Schottky contact to the surface of the SEL. In a second embodiment, a photodiode structure is integrated with the surface emitting laser by positioning a current isolation region between the photodiode and the SEL. The current isolation region should extend into a first mirror region but not into the light generation region of the active region so that the light generation region of the SEL is optically coupled to the light absorption region of the photodiode.
    Type: Grant
    Filed: August 1, 1995
    Date of Patent: November 17, 1998
    Assignee: Hewlett-Packard Company
    Inventors: Hong Lin, Long Yang, Michael R. T. Tan, Shih-Yuan Wang
  • Patent number: 5832019
    Abstract: An index-guided semiconductor laser diode made by impurity-induced layer disordering (IILD) of GaInP and AlGaInP heterostructures. In some embodiments, prior to the IILD, wing regions flanking an active mesa region are etched down close to the active layer so that the selective IILD involves a shallow diffusion only. High-performance, index-guided (AlGa).sub.0.5 In.sub.0.5 P lasers may be fabricated with this technique, analogous to those made in the AlGaAs material system. Also described are several techniques for reducing parasitic leakage current via the IILD regions, which include methods for providing p-n junctions or high band gap materials to reduce the parasitic leakage. In other embodiments, a planar structure is produced but with an ultra-thin upper cladding layer. Only a shallow IILD step is necessary to penetrate below the active region.
    Type: Grant
    Filed: November 28, 1994
    Date of Patent: November 3, 1998
    Assignee: Xerox Corporation
    Inventors: Thomas L. Paoli, Robert L. Thornton, David P. Bour, David W. Treat
  • Patent number: 5825799
    Abstract: Laser comprising a first lasing microdisk, microcylinder or microannulus defining a microcavity having a circular cross-sectional periphery and a second waveguiding micromember spaced from the first lasing micromember in a different plane and optically coupled by resonant photon tunneling. The second waveguiding micromember includes a light output coupling for providing light output from the laser without adversely affecting the Q value and low lasing threshold of the microcavity.
    Type: Grant
    Filed: May 25, 1995
    Date of Patent: October 20, 1998
    Assignee: Northwestern University
    Inventors: Seng-Tiong Ho, Daniel Yen Chu, Jian-Ping Zhang, Shengli Wu
  • Patent number: 5822350
    Abstract: A semiconductor laser includes a ridge structure includes a cladding layer having a thermal expansion coefficient. Current blocking structures are disposed at both sides of the ridge structure and include Al.sub.x Ga.sub.1-x As first current blocking layers having an Al composition x larger than 0.7 and contacting the ridge structure. In this structure, even when the Al composition of the first current blocking layers is reduced at both sides of the ridge structure, the wavelength of light absorbed by the first current blocking layers does not exceed the wavelength of laser light produced in the active layer. Therefore, unwanted absorption of the laser light at both sides of the ridge structure is avoided, resulting in a semiconductor laser with improved laser characteristics.
    Type: Grant
    Filed: September 10, 1996
    Date of Patent: October 13, 1998
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takashi Nishimura, Shoichi Karakida, Motoharu Miyashita, Diethard Marx
  • Patent number: 5818994
    Abstract: A device for coupling optical fibers to a laser array comprises a flat plate (1) with a number of V-grooves (7) and a cover (2) with a number of V-shaped grooves (8), the plate (1) and the cover (2) being fitted and adjusted to each other in such a way that the grooves (7, 8) form channels with a rhombic cross section. In these channels of such a device, pointed optical waveguides (4) may be pushed to a stop (9, 10), and may then be automatically adjusted to a laser array (3) that may be arranged on the plate (1) or cover.
    Type: Grant
    Filed: September 19, 1996
    Date of Patent: October 6, 1998
    Assignee: Alcatel N.V.
    Inventor: Jorg Hehmann
  • Patent number: 5812582
    Abstract: An vertical cavity surface emitting laser feedback system is provided which has a vertical cavity surface emitting laser for emitting a specific amount of optical radiation. A portion of the optical radiation is received by a detection means which is used to generate a feedback signal that corresponds to the amount of optical radiation being emitted by the vertical cavity surface emitting laser.
    Type: Grant
    Filed: July 8, 1997
    Date of Patent: September 22, 1998
    Assignee: Methode Electronics, Inc.
    Inventors: Patrick B. Gilliland, Andy A. Goryachev
  • Patent number: 5809194
    Abstract: A process for marking an outer jacket of an oscillating lay cable to indicate the locations of switchbacks thereunder. The process includes the step of providing detectable markings on an unjacketed cable core in predetermined position relative to the switchback. The process further includes the steps of sensing the detectable markings with a sensor prior to extruding an outer jacket over the cable core, predicting the location of the sensed markings on the cable core after a cable jacket has been extruded, and providing a marking on the cable jacket at a predetermined position relative to the predicted location of the sensed marking.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: September 15, 1998
    Assignee: Alcatel NA Cable Systems, Inc.
    Inventor: Raymond Gordon Lovie
  • Patent number: 5809052
    Abstract: A semiconductor laser array driving method for driving a semiconductor laser array having a plurality of light-emitting points arranged on a base member. The semiconductor laser array driving method has a step of driving the plurality of light-emitting points by a driving pulse current of a pulse width and a duty factor meeting an inequality: .DELTA.T.sub.1 /.DELTA.T.sub.0 <1/2, where .DELTA.T.sub.0 is a temperature rise in active layers of the light-emitting points when the semiconductor laser array is driven in a continuous drive mode using a continuous current, and .DELTA.T.sub.1 is a temperature rise in the active layers of the light-emitting points when the semiconductor laser array is driven in a pulse drive mode using a pulse current. In the semiconductor laser array driving method, the plurality of light-emitting points are driven by a driving pulse current having a duty factor of 0.4 or below meeting an inequality: y<3.1 exp(-8.9x), where x is a duty factor and y is a pulse width (.mu.s).
    Type: Grant
    Filed: October 18, 1996
    Date of Patent: September 15, 1998
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Yasuji Seko, Akemi Murakami, Hiromi Otoma, Nobuaki Ueki, Hideki Fukunaga, Hideo Nakayama, Mario Fuse
  • Patent number: 5805628
    Abstract: A semiconductor laser device includes a semiconductor substrate of a first conductivity type; opposed light emitting facets; a double heterojunction structure disposed on the semiconductor substrate and including an optical waveguide that extends between the facets and comprises a light emitting region and a lens region, the lens region being between the light emitting region and one of the facets, the double heterojunction structure including a plurality of AlGaAs series compound semiconductor layers which are thicker in the light emitting region than in the lens region; and a current blocking structure disposed on both sides of the double heterojunction structure and including a lower AlGaAs series compound semiconductor layer of the first conductivity type, an intermediate AlGaAs series compound semiconductor layer of a second conductivity type, opposite the first conductivity type, and an upper AlGaAs series compound semiconductor layer of the first conductivity type.
    Type: Grant
    Filed: October 23, 1996
    Date of Patent: September 8, 1998
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shoichi Karakida, Norio Hayafuji, Tatsuya Kimura, Motoharu Miyashita, Hirotaka Kizuki, Takashi Nishimura
  • Patent number: 5805630
    Abstract: An array of semiconductor diode lasers (11, 12) is a very suitable radiation source for various applications such as optical read and write systems and laser printers. Such an array includes a semiconductor body (10) with a substrate (1) and a layer structure provided thereon in which at least two lasers (11, 12) are formed which are mutually separated by a groove (20). In the known array, the groove (20) reaches down into the substrate (1), so that the lasers (11, 12) are electrically separated from one another. According to the invention, the array of lasers (11, 12) is provided with a groove (20) with a major portion (d) of its depth (D) which is situated within the substrate (1). As a result of this, the lasers (11, 12) of the array show a surprisingly low crosstalk. Preferably, the portion (d) of the groove (20) situated in the substrate (1) is at least 3 .mu.m deep. The best results are obtained with depths (d) of approximately 10 up to at most 40 .mu.m.
    Type: Grant
    Filed: July 11, 1994
    Date of Patent: September 8, 1998
    Assignee: U.S. Philips Corporation
    Inventors: Adriaan Valster, Carolus J. Van Der Poel, Jeroen J. L. Horikx
  • Patent number: 5799027
    Abstract: In a slant plane light emission type semiconductor laser whose laser structure can be formed on a stepped substrate by a series of MOCVD growth processes, the width of the active layer at the slant portion is set to 2.5 .mu.m or less or the angle between the flat portion and slant portion is set to 12 degrees or less. The semiconductor laser having such a structure can emit light having a single peak at the near field.
    Type: Grant
    Filed: March 19, 1997
    Date of Patent: August 25, 1998
    Assignee: Fujitsu Limited
    Inventors: Chikashi Anayama, Takehiro Fukushima, Akira Furuya
  • Patent number: 5796714
    Abstract: The optical module of the invention includes: a first substrate; a vertical-cavity surface-emitting laser including an upper surface, a bottom surface and a semiconductor multi-layered structure including at least a light-emitting layer, the vertical-cavity surface-emitting laser being supported on the first substrate; an electrode structure electrically connected with the bottom surface of the vertical-cavity surface-emitting laser, the electrode structure being supported on the first substrate; and a second substrate including a first bump and a second bump. In the optical module, an upper surface of the electrode structure and the upper surface of the vertical-cavity surface-emitting laser jut out from the first substrate. The second substrate is positioned with respect to the first substrate so that the first bump and the second bump come into contact with an upper surface of the electrode structure and the upper surface of the vertical-cavity surface-emitting laser, respectively.
    Type: Grant
    Filed: September 25, 1995
    Date of Patent: August 18, 1998
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Toyoji Chino, Kenichi Matsuda, Takayuki Yoshida, Kenzo Hatada
  • Patent number: 5793906
    Abstract: In a supercomputer that employs a large number of processors operating in parallel, groups of processors are assembled in clusters. Each processor in a cluster is provided with an array of lasers, a different one targeted for a particular detector associated with a specific processor of a different cluster. The detectors associated with the processors in the different cluster are assembled into an array of detectors. A processor wishing to communicate with a processor in a different cluster excites the laser in its associated array that is targeted to the detector of the processor with which it intends to communicate. The patterns of light of the various laser arrays are superimposed into one pattern focused on the detector array by means of an optical tunnel and a spherical lens.
    Type: Grant
    Filed: December 20, 1996
    Date of Patent: August 11, 1998
    Assignee: NEC Research Institute, Inc.
    Inventor: Alan Huang
  • Patent number: 5793787
    Abstract: A type II multiple quantum well, 4 constituent active region, optically clad electrically pumped and optically pumped laser for emitting at a wavelength greater than or equal to about 2.5 microns is disclosed. The active region comprises one or more periods, each period further comprising a barrier layer, a first conduction band layer, a valence band layer and a second conduction band layer.
    Type: Grant
    Filed: January 16, 1996
    Date of Patent: August 11, 1998
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Jerry R. Meyer, Craig A. Hoffman, Filbert J. Bartoli
  • Patent number: 5790583
    Abstract: A photonic light emitting device comprising a relatively high refractive index photonic-well semiconductor waveguide core in the form of an arcuate shape, linear shape and combinations thereof. The waveguide core is formed into a closed loop cavity for a light-emitting device or laser. The waveguide core is surrounded by relatively low refractive index medium and comprises an active medium having major and minor sides and semiconductor guiding layers proximate the major sides. The active medium and the guiding layers are so dimensioned in a transverse direction relative to the path of light propagation through the core to provide significantly increased spontaneous-emission coupling efficiency, leaading to low lasing threshold and high intrinsic modulation rates.
    Type: Grant
    Filed: May 24, 1996
    Date of Patent: August 4, 1998
    Assignee: Northwestern University
    Inventor: Seng-Tiong Ho
  • Patent number: 5790579
    Abstract: A pulsed semiconductor laser has a lower threshold current and a more stable pulse train. The structure includes a saturable absorber section has a quantum well structure for laser oscillation, a gain section, a phase control section, and a super structure grating-distributed Bragg reflector section. It uses an improved construction for overcoming problems of conventional pulsed semiconductor lasers. The improved structure includes five quantum well layers having thicknesses with respective spontaneous emission peak wavelengths of ".lambda.-2.delta.", ".lambda.+.delta.", ".lambda.+2.delta.", ".lambda.", ".lambda.-.delta." at room temperature from their upper section. .lambda. denotes the mean wavelength of the oscillating pulse laser, and .delta. denotes a fixed value less than 12 nm.
    Type: Grant
    Filed: September 5, 1996
    Date of Patent: August 4, 1998
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Kyu-Seok Lee, Joon-Tae Ahn, El-Hang Lee
  • Patent number: 5790581
    Abstract: An oscillation polarization mode selective semiconductor laser for selectively performing one of oscillations in different polarization modes, is provided. The semiconductor laser includes a substrate, a laser structure formed on the substrate, and a phase shift region formed in the laser structure. The laser structure includes an active region in which population inversion is established by a current injection thereinto. At least a portion of the phase shift region has a strained quantum well structure in which degrees of a change in refractive index for internal light in different polarization modes due to a current injection thereinto are different from each other. The polarization mode of a light output from the laser can be changed by a small amount of current injected into the phase shift region, and fluctuation in the output intensity can be suppressed during a transition operation in polarization mode.
    Type: Grant
    Filed: April 9, 1997
    Date of Patent: August 4, 1998
    Assignee: Canon Kabushiki Kaisha
    Inventor: Jun Nitta
  • Patent number: 5790721
    Abstract: A fiber-optic amplifier with reduced noise characteristics is provided. A polarization beam splitter/recombiner splits an input signal beam into two orthogonally polarized optical signals and recombines the separately treated signals. A phase controller compensates for optical path differences that result from dividing the input signal beam into two different paths. A wavelength division multiplexing coupler couples a pump laser beam with the input signal beam. A polarization maintained doped optical fiber amplifies the split optical signals while maintaining their original states of polarization. A linear polarizer rejects from each amplified split optical signal the noise with polarization orthogonal to the amplified signal. By suppressing such noise power, a portion of amplified spontaneous emission with polarization orthogonal to the signal is suppressed, thereby reducing the total output noise power.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: August 4, 1998
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Seung-hee Lee