Patents by Inventor Alfred Forchel

Alfred Forchel has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8729453
    Abstract: A sensor for electromagnetic quantities includes a bistable device whose residence times in the stable states depend on the electromagnetic quantity. The bistable device further includes a switching zone, whose dimension in the direction of a current of charge carriers is smaller than the ballistic mean free path of the charge carriers within the switching zone. An analyzer circuit may be used for generating a sensor output signal depending on the residence times of the bistable device for measuring the electromagnetic quantity. The switching device may be a resonant tunneling diode or a Y-branch nanojunction.
    Type: Grant
    Filed: August 25, 2010
    Date of Patent: May 20, 2014
    Inventors: Lukas Worschech, Alfred Forchel, Luca Gammaitoni
  • Publication number: 20110068853
    Abstract: A sensor for electromagnetic quantities includes a bistable device whose residence times in the stable states depend on the electromagnetic quantity. The bistable device further includes a switching zone, whose dimension in the direction of a current of charge carriers is smaller than the ballistic mean free path of the charge carriers within the switching zone. An analyzer circuit may be used for generating a sensor output signal depending on the residence times of the bistable device for measuring the electromagnetic quantity. The switching device may be a resonant tunneling diode or a Y-branch nanojunction.
    Type: Application
    Filed: August 25, 2010
    Publication date: March 24, 2011
    Applicant: JULIUS-MAXIMILIANS-UNIVERSITAT
    Inventors: Lukas Worschech, Alfred Forchel, Luca Gammaitoni
  • Patent number: 7696098
    Abstract: A unipolar semiconductor laser is provided in which an active region is sandwiched in a guiding structure between an upper and lower cladding layer, the lower cladding layer being situated on a semiconducting substrate. The unipolar semiconductor laser comprises a raised ridge section running from end to end between end mirrors defining the laser cavity. The ridge section aids in optical and electrical confinement. The ridge waveguide is divided in a plurality of cavity segments (at least two). Lattice structures can be arranged on and/or adjacent to these cavity segments. Each cavity segment is in contact with upper metallic electrodes. A metallic electrode coupled to the bottom surface of the semiconducting substrate facilitates current injection through the device.
    Type: Grant
    Filed: October 12, 2007
    Date of Patent: April 13, 2010
    Assignee: Nanoplus GmbH
    Inventors: Marc Fischer, Alfred Forchel
  • Publication number: 20080137704
    Abstract: A unipolar semiconductor laser is provided in which an active region is sandwiched in a guiding structure between an upper and lower cladding layer, the lower cladding layer being situated on a semiconducting substrate. The unipolar semiconductor laser comprises a raised ridge section running from end to end between end mirrors defining the laser cavity. The ridge section aids in optical and electrical confinement. The ridge waveguide is divided in a plurality of cavity segments (at least two). Lattice structures can be arranged on and/or adjacent to these cavity segments. Each cavity segment is in contact with upper metallic electrodes. A metallic electrode coupled to the bottom surface of the semiconducting substrate facilitates current injection through the device.
    Type: Application
    Filed: October 12, 2007
    Publication date: June 12, 2008
    Applicant: Nanoplus GmBH
    Inventors: Marc Oliver Fischer, Alfred Forchel
  • Patent number: 7301977
    Abstract: A unipolar semiconductor laser is provided in which an active region is sandwiched in a guiding structure between an upper and lower cladding layer, the lower cladding layer being situated on a semiconducting substrate. The unipolar semiconductor laser comprises a raised ridge section running from end to end between end mirrors defining the laser cavity. The ridge section aids in optical and electrical confinement. The ridge waveguide is divided in a plurality of cavity segments (at least two). Lattice structures can be arranged on and/or adjacent to these cavity segments. Each cavity segment is in contact with upper metallic electrodes. A metallic electrode coupled to the bottom surface of the semiconducting substrate facilitates current injection through the device.
    Type: Grant
    Filed: June 10, 2004
    Date of Patent: November 27, 2007
    Assignee: Nanoplus GmbH
    Inventors: Marc Oliver Fischer, Alfred Forchel
  • Publication number: 20050276298
    Abstract: A unipolar semiconductor laser is provided in which an active region is sandwiched in a guiding structure between an upper and lower cladding layer, the lower cladding layer being situated on a semiconducting substrate. The unipolar semiconductor laser comprises a raised ridge section running from end to end between end mirrors defining the laser cavity. The ridge section aids in optical and electrical confinement. The ridge waveguide is divided in a plurality of cavity segments (at least two). Lattice structures can be arranged to these cavity segments. Each cavity segment is in contact with upper metallic electrodes. A metallic electrode coupled to the bottom surface of the semiconducting substrate facilitates current injection through the device.
    Type: Application
    Filed: June 10, 2004
    Publication date: December 15, 2005
    Inventors: Marc Fischer, Alfred Forchel
  • Patent number: 6846689
    Abstract: A semiconductor laser (22) with a semiconductor substrate (11), a laser layer (13) arranged on the semiconductor substrate, a waveguide ridge (15) arranged at a distance from the laser layer, and a strip-shaped lattice structure (23) arranged in parallel to the laser layer is disclosed. The lattice structure (23) includes two structural regions (24, 25) which are arranged on both sides of the waveguide ridge (15) and are formed at a distance from the laser layer (13) above the laser layer (13). A process for the production of such a semiconductor laser is also disclosed.
    Type: Grant
    Filed: October 2, 2003
    Date of Patent: January 25, 2005
    Inventors: Alfred Forchel, Martin Kamp
  • Publication number: 20040072379
    Abstract: A semiconductor laser (22) with a semiconductor substrate (11), a laser layer (13) arranged on the semiconductor substrate, a waveguide ridge (15) arranged at a distance from the laser layer, and a strip-shaped lattice structure (23) arranged in parallel to the laser layer is disclosed. The lattice structure (23) includes two structural regions (24, 25) which are arranged on both sides of the waveguide ridge (15) and are formed at a distance from the laser layer (13) above the laser layer (13). A process for the production of such a semiconductor laser is also disclosed.
    Type: Application
    Filed: October 2, 2003
    Publication date: April 15, 2004
    Inventors: Alfred Forchel, Martin Kamp
  • Publication number: 20040027154
    Abstract: An electronic device of nanometric dimensions which exhibits non-linear transistor or rectifying action comprises a region (40) fabricated to provide ballistic transport properties for electron flow, with conductance paths (42, 44, 46) having quantum point contacts (40q) formed in region (40), each path having an associated reservoir of electrons, or contact (50), with an electro-chemical potential, and a linear-response conductance which depends on the energy of electrons injected into the path. An alternating voltage Vl, Vr, is applied across conductance paths (44,46), and a rectified voltage Vc is developed at conductance path (42). Altematively, a constant voltage may be applied to terminal (44), to modulate the characteristics of electron flow through conductance paths (42, 46), in a transistor-like manner. The device may perform a logic AND or OR function, or be used as a frequency multiplier.
    Type: Application
    Filed: August 15, 2003
    Publication date: February 12, 2004
    Inventors: Lars I Samuelson, Honggi Xu, Alfred Forchel, Lukas Worschech
  • Patent number: 6671306
    Abstract: A semiconductor laser (22) with a semiconductor substrate (11), a laser layer (13) arranged on the semiconductor substrate, a waveguide ridge (15) arranged at a distance from the laser layer, and a strip-shaped lattice structure (23) arranged in parallel to the laser layer is disclosed. The lattice structure (23) includes two structural regions (24, 25) which are arranged on both sides of the waveguide ridge (15) and are formed at a distance from the laser layer (13) above the laser layer (13). A process for the production of such a semiconductor laser is also disclosed.
    Type: Grant
    Filed: April 21, 1999
    Date of Patent: December 30, 2003
    Inventors: Alfred Forchel, Martin Kamp