Patents by Inventor Kazuki SUGA

Kazuki SUGA 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).

  • Publication number: 20230106955
    Abstract: A semiconductor optical device includes: a lower mesa structure extending in a stripe shape and composed of some layers including an active layer; a buried layer configured to bury both sides of the lower mesa structure and made of indium phosphide; and an upper mesa structure extending in a stripe shape and composed of some layers including a bottom layer made of phosphorus-free materials, the bottom layer having a bottom surface protruding from a topmost layer of the lower mesa structure, the bottom surface being in contact with the lower mesa structure and the buried layer.
    Type: Application
    Filed: March 7, 2022
    Publication date: April 6, 2023
    Inventors: Kazuki SUGA, Kouji NAKAHARA
  • Publication number: 20220085574
    Abstract: An optical semiconductor device includes a multi-quantum well layer including well layers and barrier layers alternately overlapping with each other, an optical confinement layer, and a guide layer interposed between the multi-quantum well layer and the optical confinement layer. Each barrier layer is an undoped layer and an outermost layer is one of the barrier layers. The optical confinement layer has a refractive index that is greater than that of the outermost layer and a band gap that is smaller than that of the outermost layer. The guide layer includes a first adjacent layer in contact with the outermost layer and the guide layer is thinner than the optical confinement layer. Each of the optical confinement layer and the guide layer is an n-type semiconductor layer. The first adjacent layer of the guide layer has a band gap that is larger than that of the optical confinement layer.
    Type: Application
    Filed: March 29, 2021
    Publication date: March 17, 2022
    Inventors: Kazuki SUGA, Kouji NAKAHARA
  • Patent number: 11189991
    Abstract: A semiconductor optical element is configured to emit or absorb light and includes a lower structure that includes a multiple quantum well layer; an upper mesa structure that is disposed on the lower structure; a current injection structure that is disposed on the upper mesa structure, when seen from an optical axis of the emitted or absorbed light, a width of a portion of the current injection structure in contact with the upper mesa structure is smaller than a width of the upper mesa structure, the portion of the current injection structure in contact with the upper mesa structure consisting of InP, and an average refractive index of the upper mesa structure is higher than a refractive index of the InP forming the current injection structure; and an insulating film covering both side surfaces of the upper mesa structure and a part of an upper surface of the upper mesa structure.
    Type: Grant
    Filed: April 10, 2020
    Date of Patent: November 30, 2021
    Assignee: Lumentum Japan, Inc.
    Inventors: Kouji Nakahara, Kazuki Suga
  • Publication number: 20210044089
    Abstract: A semiconductor optical element is configured to emit or absorb light and includes a lower structure that includes a multiple quantum well layer; an upper mesa structure that is disposed on the lower structure; a current injection structure that is disposed on the upper mesa structure, when seen from an optical axis of the emitted or absorbed light, a width of a portion of the current injection structure in contact with the upper mesa structure is smaller than a width of the upper mesa structure, the portion of the current injection structure in contact with the upper mesa structure consisting of InP, and an average refractive index of the upper mesa structure is higher than a refractive index of the InP forming the current injection structure; and an insulating film covering both side surfaces of the upper mesa structure and a part of an upper surface of the upper mesa structure.
    Type: Application
    Filed: April 10, 2020
    Publication date: February 11, 2021
    Inventors: Kouji NAKAHARA, Kazuki SUGA