Patents Represented by Attorney Richard D. Laumann

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  • Heterojunction bipolar transistor
    Patent number: 4794440
    Abstract: A heterojunction bipolar transistor having means for changing carrier transport properties is described.
    Type: Grant
    Filed: December 30, 1987
    Date of Patent: December 27, 1988
    Assignee: American Telephone and Telegraph Company, AT&T Bell laboratories
    Inventors: Federico Capasso, Arthur C. Gossard, John R. Hayes, Roger J. Malik, Pierre M. Petroff
  • Method for making a complementary device containing MODFET
    Patent number: 4791072
    Abstract: Complementary structure implemented in Group III-V compound semiconductors is obtained by using an n-channel field effect transistor and a p-channel MODFET.
    Type: Grant
    Filed: April 7, 1987
    Date of Patent: December 13, 1988
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventor: Richard A. Kiehl
  • Devices having low loss curved or tapered optical waveguides
    Patent number: 4787689
    Abstract: An optical device comprising an optical waveguide having a varying refractive index has low radiation loss. The waveguide may be either curved or tapered.
    Type: Grant
    Filed: May 3, 1985
    Date of Patent: November 29, 1988
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventors: Steven K. Korotky, Enrique A. J. Marcatili
  • Stabilized cleaved-coupled cavity laser
    Patent number: 4785454
    Abstract: A light transmitter comprising a cleaved-coupled cavity laser and stabilization means to maintain the laser in single longitudinal mode operation is described.
    Type: Grant
    Filed: May 13, 1983
    Date of Patent: November 15, 1988
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventors: Nils A. Olsson, Won-Tien Tsang
  • Device having strain induced region of altered bandgap
    Patent number: 4772924
    Abstract: A strained layer superlattice comprising Ge.sub.x Si.sub.1-x layers interleaved with Si layers is an excellent photodetector at infrared wavelengths due to the large shift in bandgap caused by the strain in the superlattice.
    Type: Grant
    Filed: November 25, 1987
    Date of Patent: September 20, 1988
    Inventors: John C. Bean, David V. Lang, Thomas P. Pearsall, Roosevelt People, Henryk Temkin
  • Method of fabricating non-silicon materials on silicon substrate using an alloy of Sb and Group IV semiconductors
    Patent number: 4769341
    Abstract: A semiconductor device comprising an epitaxially grown tin and Group IV compound semiconductor region on which at least one other semiconductor is grown lattice matched to the adjacent portion of the tin containing region. A large number of semiconductors may thus be grown.
    Type: Grant
    Filed: December 29, 1986
    Date of Patent: September 6, 1988
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventor: Sergey Luryi
  • Stress relief in epitaxial wafers
    Patent number: 4769689
    Abstract: The specification describes an epitaxial structure designed to reduce or eliminate the bowing of semiconductor wafers due to stresses caused by lattice mismatch between a heavily boron doped substrate and a lightly doped epitaxial layer. The lattice mismatch is reduced or eliminated by doping germanium into the substrate prior to epitaxial growth.
    Type: Grant
    Filed: July 13, 1987
    Date of Patent: September 6, 1988
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventor: Wen Lin
  • Avalanche photodetector
    Patent number: 4755860
    Abstract: An avalanche photodetector using a quantum well superlattice in which impact ionization of carriers in the well layers occurs across the band-edge discontinuity is described.
    Type: Grant
    Filed: August 5, 1986
    Date of Patent: July 5, 1988
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventors: Jeremy Allam, Federico Capasso, Alfred Y. Cho
  • Devices using avalanche photodiode and capable of detecting a small number of photons
    Patent number: 4754131
    Abstract: An avalanche photodetector having separate absorption and multiplication regions comprising Group III-V compound semiconductors is useful as a detector of small numbers of photons when it is operated with an above threshold bias voltage at ambient temperature.
    Type: Grant
    Filed: December 31, 1985
    Date of Patent: June 28, 1988
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventors: Clyde G. Bethea, Barry F. Levine
  • Optical waveguide resonator filters
    Patent number: 4750801
    Abstract: An optical filter using first and second grating sections separated by a changed refractive index section operates as a narrowband grating resonator.
    Type: Grant
    Filed: September 30, 1985
    Date of Patent: June 14, 1988
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventor: Rodney C. Alferness
  • Structures including quantum well wires and boxes
    Patent number: 4751194
    Abstract: A method of fabricating quantum well wires and boxes is described in which interdiffusion in a semiconductor having a compositional profile is enhanced by the presence of defects created by ion implantation in localized regions.
    Type: Grant
    Filed: June 27, 1986
    Date of Patent: June 14, 1988
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventors: Joel B. Cibert, Arthur C. Gossard, Stephen J. Pearton, Pierre M. Petroff
  • Depletion stop transistor
    Patent number: 4750025
    Abstract: We have found that transistors have desirable device characteristics when the base region is composed of a lightly doped layer near the emitter junction and a heavily doped layer near the collector junction. The edge of the depletion region at the emitter-base junction is designed to stop in the lightly doped base region.
    Type: Grant
    Filed: January 30, 1986
    Date of Patent: June 7, 1988
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventors: Chung Y. Chen, Alfred Y. Cho
  • Modulation-doped photodetector
    Patent number: 4739385
    Abstract: A modulation-doped field effect photodetector has a fast response time.
    Type: Grant
    Filed: January 12, 1987
    Date of Patent: April 19, 1988
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventors: Clyde G. Bethea, Chung Y. Chen, Alfred Y. Cho
  • Multicavity optical device held together by metallic film
    Patent number: 4734380
    Abstract: Semiconductor lasers having cleaved optically coupled cavities operating electrically isolated produce output of a single longitudinal mode. Wavelength tuning of the single longitudinal mode is possible.
    Type: Grant
    Filed: May 27, 1986
    Date of Patent: March 29, 1988
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventor: Won-Tien Tsang
  • Short pulse laser
    Patent number: 4727553
    Abstract: A short pulse laser is described which has saturable absorption, saturable gain, group velocity dispersion, and self phase modulation means within a single optical cavity.
    Type: Grant
    Filed: October 28, 1985
    Date of Patent: February 23, 1988
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventors: Richard L. Fork, James P. Gordon, Janis A. Yaldmanis
  • Silicon germanium photodetector
    Patent number: 4725870
    Abstract: A photodetector, comprising a Ge.sub.x Si.sub.1-x superlattice region between two silicon cladding layers in which the Ge.sub.x Si.sub.1-x layers absorb light, is described.
    Type: Grant
    Filed: November 18, 1985
    Date of Patent: February 16, 1988
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventors: John C. Bean, Sergey Luryi, Thomas P. Pearsall
  • Integrated devices including cleaved semiconductor lasers
    Patent number: 4707219
    Abstract: A new technique called stop cleaving permits semiconductor lasers having etched mirrors to be fabricated on a common substrate with other optical or electronic components such as photodetectors and field-effect transistors.
    Type: Grant
    Filed: May 14, 1985
    Date of Patent: November 17, 1987
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventor: Chung Y. Chen
  • Negative transconductance device
    Patent number: 4704622
    Abstract: A resonant tunneling device having a one-dimensional quantum well comprises a semiconductor region capable of exhibiting one-dimensional quantization. The device comprises source and drain contact regions adjoining such semiconductor region as well as a gate contact for applying a field to such region; the device can be implemented, e.g., by methods of III-V deposition and etching technology. Under suitable source-drain bias conditions the device can function as a transistor having negative transconductance.
    Type: Grant
    Filed: November 27, 1985
    Date of Patent: November 3, 1987
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventors: Federico Capasso, Sergey Luryi
  • Timing recovery circuit
    Patent number: 4704722
    Abstract: Prior art circuits for recovering timing information from baseband digital signals include a rectifier and a separate phase detector for controlling the phase of a phase-locked voltage-controlled oscillator. In the circuit described herein, an antiparallel diode pair is used to perform the two functions of rectification and phase detection. The resulting timing circuit is, thereby, simplified. Alternatively, a dual-gate field effect transistor may be used.
    Type: Grant
    Filed: June 20, 1984
    Date of Patent: November 3, 1987
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventor: Paul S. Henry
  • Method for growing patterned metal layers
    Patent number: 4701347
    Abstract: Patterned metal growth is obtained on a substrate by illuminating the substrate in the presence of a metal containing molecule adsorbed on the substrate. After initial illumination, the photoreacted molecules catalyze further metal growth without further illumination.
    Type: Grant
    Filed: April 18, 1986
    Date of Patent: October 20, 1987
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventor: Gregg S. Higashi