Patents by Inventor Kenzo Fujiwara

Kenzo Fujiwara 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).

  • Process for producing a DFB laser with a diffraction grating superlattice
    Patent number: 4843032
    Abstract: A semiconductor optical element having a layer which exhibits a function of diffraction grating between a first cladding layer and a second cladding layer, wherein the layer which exhibits the function of diffraction grating consists of a superlattice layer in which crystal layers are periodically mixed to constitute a semiconductor grating layer.
    Type: Grant
    Filed: June 30, 1988
    Date of Patent: June 27, 1989
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yasunori Tokuda, Kenzo Fujiwara
  • Semiconductor laser device
    Patent number: 4817110
    Abstract: A semiconductor laser having an active layer of quantum well structure, where the resonator loss is enhanced thereby to conduct an oscillation at a high quantum level.
    Type: Grant
    Filed: July 24, 1987
    Date of Patent: March 28, 1989
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yasunori Tokuda, Kenzo Fujiwara, Noriaki Tsukada, Keisuke Kojima, Yoshinori Nomura, Teruhito Matsui
  • Composite resonator-type semiconductor laser device
    Patent number: 4788689
    Abstract: At least a portion of the optical waveguide is formed in a superlattice structure or in a quantum well structure, and crystals are mixed in the portions of the superlattice structure or the quantum well structure that divide the resonator to decrease the refractive index of these portions, in order to form two or more laser portions having different cavity lengths. The semiconductor device can be formed easily and precisely without employing cleavage which involves cumbersome manufacturing steps. Further, the crystal need not be grown on the groove but may simply be grown on a flat surface, making it possible to easily and precisely produce the semiconductor laser device.
    Type: Grant
    Filed: February 18, 1986
    Date of Patent: November 29, 1988
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yasunori Tokuda, Kenzo Fujiwara
  • Semiconductor optical element and a process for producing the same
    Patent number: 4786951
    Abstract: A semiconductor optical element having a layer which exhibits a function of diffraction grating between a first cladding layer and a second cladding layer, wherein the layer which exhibits the function of diffraction grating consists of a superlattice layer in which crystal layers are periodically mixed to constitute a semiconductor grating layer.
    Type: Grant
    Filed: February 11, 1986
    Date of Patent: November 22, 1988
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yasunori Tokuda, Kenzo Fujiwara
  • Armature winding of a split stator
    Patent number: 4594522
    Abstract: The present invention relates to an armature winding of a split stator having a slotted core divided by at least two circumferentially-spaced split lines to facilitate the disassembly and assembly of the split stator. The armature winding comprises armature coils in the slots of the stator core connected to provide poles and arranged to provide a plurality of armature coils divided at the split lines. Connecting and disconnecting means are provided to connect and disconnect the armature coils when the split stator is assembled and disassembled, respectively.
    Type: Grant
    Filed: September 20, 1984
    Date of Patent: June 10, 1986
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Kenzo Fujiwara, Norio Takeuchi, Yoji Nakatsuka, Tsuyoshi Horita, Yuji Nakanishi, Shigeru Murasato