Patents by Inventor Wolfgang Thulke

Wolfgang Thulke 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: 5333141
    Abstract: A modulatable laser diode for high frequencies, such as a tuneable turn guide distributed feedback laser diode, that has a central layer provided for a separate current supply located between a tuning layer and an active layer. The tuning layer has a quantum well structure. A ridge waveguide is provided for the laser diode and the layer sequence is limited to a strip-shaped mesa on the substrate in order to reduce the parasitic capacitances.
    Type: Grant
    Filed: July 8, 1993
    Date of Patent: July 26, 1994
    Assignee: Siemens Aktiengesellschaft
    Inventors: Thomas Wolf, Wolfgang Thulke
  • Patent number: 5260960
    Abstract: A tunable laser diode on a semi-insulating substrate having a stripe-shaped layer structure has an intermediate layer between an active layer and a tuning layer that is grown-over by an confinement layer that is doped for the same conductivity type as the intermediate layer. An oppositely doped, lateral region is electrically connected via an identically doped lower region to the active layer. An upper region is likewise oppositely doped and is electrically connected to the tuning layer. A contact layer is essentially planarly applied on the surface of the confinement layer and has respective portions on the appertaining regions on which the contacts provided with adequate bond areas are applied with a further contact layer for the common contact.
    Type: Grant
    Filed: April 23, 1992
    Date of Patent: November 9, 1993
    Assignee: Siemens Aktiengesellschaft
    Inventors: Markus-Christian Amann, Stefan Illek, Wolfgang Thulke
  • Patent number: 5222087
    Abstract: A TTG-DFB laser diode on a doped substrate having a stripe-shaped layer structure that has an intermediate layer between an active layer and a tuning layer. A confinement layer laterally adjoins this layer structure at both sides, is doped for the same conductivity type as the substrate and is electrically conductively connected to the substrate through an interruption of the layers situated therebelow. An upper region, that respectively extends up to the surface and that is oppositely doped, is formed in the confinement layer above the layer structure. A lateral region, separated therefrom and that is electrically conductively connected via a lower confinement layer to a side of the layer structure facing toward the substrate, is formed in the confinement layer.
    Type: Grant
    Filed: April 23, 1992
    Date of Patent: June 22, 1993
    Assignee: Siemens Aktiengesellschaft
    Inventors: Wolfgang Thulke, Stefan Illek
  • Patent number: 5208878
    Abstract: A monolithically integrated laser diode waveguide combination on a semi-insulating substrate has in an active region thereof a laser diode with a waveguide layer, an intermediate layer, an active layer, and a grating layer arranged between portions of a lower cover layer. Above this laser strip, an upper cover layer with a central contact layer is located thereupon together with a central contact. An activation of the active layer occurs via the lower cover layer, a lateral contact layer applied on the coating layer, and lateral contacts.
    Type: Grant
    Filed: October 2, 1991
    Date of Patent: May 4, 1993
    Assignee: Siemens Aktiengesellschaft
    Inventor: Wolfgang Thulke
  • Patent number: 5027364
    Abstract: Laser diode with BH double hetero-structure and lateral channels for lateral current limitation, whereby the laser-active stripes are provided with lateral spacer layers and these spacer layers are fashioned before the etching of the lateral channels of a semiconductor material that cannot be attached by the etchant, so that the laser-active stripes have an undamaged, straight line, lateral limitation. This laser diode has a low threshold current and a high differential efficiency given a high output power. Parasitic capacitances are voided by transverse channels and a structured metal contact.
    Type: Grant
    Filed: December 18, 1989
    Date of Patent: June 25, 1991
    Assignee: Siemens Aktiengesellschaft
    Inventor: Wolfgang Thulke
  • Patent number: 5008893
    Abstract: A tunable semiconductor laser which is formed on a substrate 2 which has a first contact 14 on one surface and a third contact 16 on the opposite surface so as to supply the operating current which is laterally limited to a laser-active stripe through a barrier layer 4 l and including a second contact 15 on a ridge waveguide 11, 12, 13 so as to inject charge carriers into a tuning layer 9 mounted adjacent an active layer 6 and which is separated from the active layer by highly doped central layer 10 so as to allow tuning of the laser.
    Type: Grant
    Filed: February 15, 1990
    Date of Patent: April 16, 1991
    Assignee: Siemens Aktiengesellschaft
    Inventors: Markus-Christian Amann, Gerhard Baumann, Jochen Heinen, Wolfgang Thulke
  • Patent number: 4963507
    Abstract: In the manufacture of laser diodes having a stripe-shaped, active layer, a problem arises upon application of lateral layers, particularly of blocking pn-junctions for lateral current conduction, in that these layers are undesired above the active layer. By applying a protective cover layer that will dissolve in super-cooled melts of the material of the lateral layers, before the growth of the lateral layers, the growth of the lateral layers, particularly blocking pn-junctions, above the active stripe is avoided since the cover layer dissolves in the melt given epitaxial application of the lateral layers.
    Type: Grant
    Filed: April 27, 1988
    Date of Patent: October 16, 1990
    Assignee: Siemens Aktiengesellschaft
    Inventors: Markus-Christian Amann, Wolfgang Thulke, Gerhard Baumann
  • Patent number: 4656636
    Abstract: A method for integrating a DFB laser and a passive strip waveguide on a substrate. A layer stack is produced in a first epitaxy step, the layer stack having a laser-active layer and a surface-wide grating on the uppermost layer, and eroding the stack area-wise, but only down to a layer under the laser-active layer, not down to the substrate, by means of etching to create a step separating the laser region from the passive strip waveguide region. By employing an etching stop layer, the etching can ensue self-adjustingly, and the coupling between the laser-active layer and the passive strip waveguide region occurs not by end coupling, but by surface coupling. Only two epitaxy steps are required for the complete manufacture of the structure, and a strip required for the definition of the laser and of the waveguide can be produced in the same single method step.
    Type: Grant
    Filed: December 23, 1985
    Date of Patent: April 7, 1987
    Assignee: Siemens Aktiengesellschaft
    Inventors: Markus-Christian Amann, Hans F. Mahlein, Bernhard Stegmueller, Wolfgang Thulke, Gerhard Winzer, Ulrich Wolff