Patents by Inventor Yuichi Matsushima

Yuichi Matsushima 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: 4660934
    Abstract: A method for manufacturing diffraction grating, in which after forming, on a substrate, one of a negative type photoresist film (an N film) and a positive type photoresist film (a P film) to cover a first region A and the other of the negative type photoresist film and the positive type photoresist film, or the latter film on the former one to cover a second region B, the first region and the second region are subjected to two-beam interference exposure, thereby forming a diffraction grating in which corrugations in the first region and the second region are reverse in phase to each other, through utilization of characteristics of the negative type photoresist film and the positive type photoresist film.
    Type: Grant
    Filed: March 12, 1985
    Date of Patent: April 28, 1987
    Assignee: Kokusai Denshin Denwa Kabushiki Kaisha
    Inventors: Shigeyuki Akiba, Katsuyuki Utaka, Kazuo Sakai, Yuichi Matsushima
  • Patent number: 4653058
    Abstract: A distributed feedback semiconductor laser with a monitor, which has periodic corrugations on a light emitting layer or an adjoining layer in the direction of travel of light and performs laser oscillation by the injection of a current into said light emitting layer. In accordance with the present invention, a laser region forming said distributed feedback semiconductor laser and a monitor region for detecting the output of said laser region are disposed on the same substrate. A gap between said monitor region and said laser region is filled with a semiconductor of an energy bandgap larger than that of the light emitting layer of said laser region.
    Type: Grant
    Filed: April 21, 1983
    Date of Patent: March 24, 1987
    Assignee: 501 Kokusai Denshin Denwa Kabushiki Kaisha
    Inventors: Shigeyuki Akiba, Katsuyuki Utaka, Kazuo Sakai, Yuichi Matsushima
  • Patent number: 4653059
    Abstract: A distributed feedback semiconductor laser which has periodic corrugations formed in a light emitting layer or an adjoining layer to extend in the direction of travel of light. A window region formed by a semiconductor layer larger in energy gap than the light emitting layer is provided on the extension line of one end of a laser region formed in the light emitting layer. The length of the window region is so limited as to prevent substantial reflection of laser output light in the window region. The end face of the laser on the opposite side from the window region is coated with a film for increasing reflectivity.
    Type: Grant
    Filed: January 3, 1985
    Date of Patent: March 24, 1987
    Assignee: Kokusai Denshin Denwa Kabushiki Kaisha
    Inventors: Shigeyuki Akiba, Katsuyuki Utaka, Kazuo Sakai, Yuichi Matsushima
  • Patent number: 4648096
    Abstract: A distributed feedback semiconductor laser which has periodic corrugations in a light emitting layer or an adjoining layer in the direction of travel of light and performs laser oscillation by the injection of carriers into said light emitting layer. In accordance with the present invention, there are provided, in the neighborhood of the center of a laser region, a region for changing the phase of the periodic corrugations by about 180 degrees, and, on the extension of the laser oscillation region at both sides thereof, a window region formed of a semiconductor larger in energy gap but smaller in refractive index than the light emitting layer, the length of the window region being so limited as to prevent substantial reflection of laser output light in the window region.
    Type: Grant
    Filed: October 15, 1984
    Date of Patent: March 3, 1987
    Assignee: Kokusai Denshim Denwa Kabushiki Kaisha
    Inventors: Shigeyuki Akiba, Katsuyuki Utaka, Kazuo Sakai, Yuichi Matsushima
  • Patent number: 4633474
    Abstract: A distributed feedback semiconductor laser which has periodic corrugations formed in a layer adjoining a light emitting layer so as to extend in the direction of travel of light and performs laser oscillation by the injection of current into the light emitting layer, in which a part of at least one metal electrode has a TM mode suppressing region disposed at a position where light is essentially distributed in the thickwise direction of the laser. A window region formed of a semiconductor larger in energy gap than the light emitting layer is disposed at both ends of the laser oscillation region in the direction of travel of light, the length of the window region being limited so that no substantial reflection occurs therein.
    Type: Grant
    Filed: December 5, 1984
    Date of Patent: December 30, 1986
    Assignee: Kokusai Denshin Denwa Kabushiki Kaisha
    Inventors: Shigeyuki Akiba, Katsuyuki Utaka, Kazuo Sakai, Yuichi Matsushima
  • Patent number: 4589117
    Abstract: A semiconductor laser, in which active layers are provided on the top surface of the mesa and the remainder surface in a substrate as a first semiconductor layer. Second semiconductor layers are provided on the active layers to such a thickness that the second semiconductor layer may not reach the first semiconductor layer on the mesa. Third semiconductor layers are provided on the second semiconductor layer to such a thickness that the third semiconductor layers may be flush with or higher than the first semiconductor layer on the mesa, so that the first semiconductor layer on the top surface of the mesa is just jointed with the third semiconductor layer on the remainder surface in the substrate.
    Type: Grant
    Filed: June 9, 1983
    Date of Patent: May 13, 1986
    Assignee: Kokusai Denshin Denwa Kabushiki Kaisha
    Inventors: Katsuyuki Utaka, Kazuo Sakai, Shigeyuki Akiba, Yuichi Matsushima
  • Patent number: 4573161
    Abstract: A semiconductor laser, in which layers on both sides of the light emitting region are each formed by laminating a plurality of semiconductor layers of different energy band gaps and thicknesses smaller than 0.03 .mu.m. The thickness of the thin film layer of at least one kind of the semiconductor thin film layers of a thickness less than 0.03 .mu.m varies in dependence upon the layers remoteness from the light emitting region. The light emitting region and the layers on both sides of the light emitting region are each formed of a mixed crystal which consists of indium, gallium, arsenic and phosphorus, or indium, gallium, aluminum and arsenic and which has a lattice constant difference less than 0.3% relative to indium phosphide.
    Type: Grant
    Filed: November 30, 1983
    Date of Patent: February 25, 1986
    Assignee: Kokusai Denshin Denwa Kabushiki Kaisha
    Inventors: Kazuo Sakai, Yuichi Matsushima, Shigeyuki Akiba, Katsuyuki Utaka
  • Patent number: 4553239
    Abstract: A distributed feedback semiconductor laser which has periodic corrugations on a light emitting layer or an adjoining layer in the direction of travel of light and performs laser oscillation by the injection of current into the light emitting layer. In accordance with the present invention, a semiconductor having an energy gap larger than that of light emitting layer is formed so as to be extended from a current injection region. The semiconductor is formed uniformly and sufficiently distributed in the current injection region.
    Type: Grant
    Filed: February 8, 1983
    Date of Patent: November 12, 1985
    Assignee: Kokusai Denshin Denwa Kabushiki Kaisha
    Inventors: Shigeyuki Akiba, Katsuyuki Utaka, Kazuo Sakai, Yuichi Matsushima
  • Patent number: 4506367
    Abstract: A distributed feedback semiconductor laser which is characterized in that periodic corrugations are performed in the surface of an InGaAsP quaternary layer so that an InP layer is grown thereon so as to overcome difficulties in prior arts.
    Type: Grant
    Filed: October 6, 1982
    Date of Patent: March 19, 1985
    Assignee: Kokusai Denshin Denwa Kabushiki Kaisha
    Inventors: Shigeyuki Akiba, Kazuo Sakai, Katsuyuki Utaka, Yuichi Matsushima
  • Patent number: 4383266
    Abstract: An avalanche photo diode provided with a guard ring around a photo detecting region having a pn junction, in which semiconductor layers of the photo detecting region having a pn junction, different in conductivity type from a semiconductor of the guard ring, are composed of a second semiconductor layer formed in contact with a first semiconductor layer forming the pn junction of the photo detecting region and of the same conductivity type as the semiconductor of the guard ring, and a third semiconductor layer formed in contact with the second semiconductor layer and having a larger band gap than the second semiconductor layer, and in which the tip end of the guard ring is formed to extend down into the third semiconductor layer.
    Type: Grant
    Filed: September 16, 1980
    Date of Patent: May 10, 1983
    Assignee: Kokusai Denshin Denwa Kabushiki Kaisha
    Inventors: Kazuo Sakai, Yuichi Matsushima, Shigeyuki Akiba, Takaya Yamamoto