Patents by Inventor Koyoshi Takei

Koyoshi Takei 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).

  • Method of manufacturing non-regrowth distributed feedback ridge semiconductor
    Patent number: 6291256
    Abstract: There is provided a method of manufacturing a DFB semiconductor laser in which a laser substrate having a cladding layer which is a material for a ridge stripe stacked on an active is formed. The cladding layer as a material for a ridge stripe is etched to form a ridge stripe having flat portions on both sides thereof and a flat top portion protruding therefrom. A protective film and a resist layer are formed to cover the flat portions on both sides and the flat upper surface. A latent image of a grating having a periodic structure is formed in the direction in which the ridge stripe extends is formed on the resist layer. The resist layer is developed and the flat portions on both sides are etched to form a grating on both lateral portions and to remove the protective film. An electrode is formed on the flat top portion, the interface between the ridge strip and the electrode being a smooth surface.
    Type: Grant
    Filed: September 21, 1999
    Date of Patent: September 18, 2001
    Assignee: Pioneer Corporation
    Inventors: Nong Chen, Yoshiaki Watanabe, Koyoshi Takei, Kiyofumi Chikuma
  • Non-regrowth distributed feedback ridge semiconductor laser and method of manufacturing the same
    Patent number: 5982804
    Abstract: There is provided a method of manufacturing a DFB semiconductor laser in which a laser substrate having a cladding layer which is a material for a ridge stripe stacked on an active is formed. The cladding layer as a material for a ridge stripe is etched to form a ridge stripe having flat portions on both sides thereof and a flat top portion protruding therefrom. A protective film and a resist layer are formed to cover the flat portions on both sides and the flat upper surface. A latent image of a grating having a periodic structure is formed in the direction in which the ridge stripe extends is formed on the resist layer. The resist layer is developed and the flat portions on both sides are etched to form a grating on both lateral portions and to remove the protective film. An electrode is formed on the flat top portion, the interface between the ridge strip and the electrode being a smooth surface.
    Type: Grant
    Filed: July 25, 1997
    Date of Patent: November 9, 1999
    Assignee: Pioneer Electronic Corporation
    Inventors: Nong Chen, Yoshiaki Watanabe, Koyoshi Takei, Kiyofumi Chikuma