Patents by Inventor Tatsurou HIRAKI

Tatsurou HIRAKI 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).

  • Optical modulator
    Patent number: 11747659
    Abstract: The optical modulator includes a lower cladding layer formed on a substrate, a core formed on the lower cladding layer, and an upper cladding layer formed on the core. The core is made of an InP-based semiconductor having a bandgap corresponding to a desired wavelength. Refractive indexes of the lower cladding layer and upper cladding layer are equal to or less than a refractive index of InP.
    Type: Grant
    Filed: February 8, 2019
    Date of Patent: September 5, 2023
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Tatsurou Hiraki, Takaaki Kakitsuka, Shinji Matsuo
  • Semiconductor Optical Element
    Publication number: 20210175685
    Abstract: A wavelength tunable laser formed on a substrate made of single-crystal silicon is provided. The wavelength tunable laser includes a light emitting portion made of a III-V compound semiconductor, and external resonators provided with an optical filter. Cores included in the external resonators are made of one of SiN, SiON, and SiOn (n is smaller than 2).
    Type: Application
    Filed: March 28, 2019
    Publication date: June 10, 2021
    Applicant: Nippon Telegraph and Telephone Corporation
    Inventors: Takuma AIHARA, Shinji MATSUO, Tai TSUCHIZAWA, Takaaki KAKITSUKA, Tatsurou HIRAKI
  • Optical Modulator
    Publication number: 20200400977
    Abstract: To make it possible to more easily improve modulation efficiency in an optical modulator using a core made of an InP-based semiconductor. The optical modulator includes a lower cladding layer 102 formed on a substrate 101, a core 103 formed on the lower cladding layer 102, and an upper cladding layer 104 formed on the core 103. The core 103 is made of an InP-based semiconductor having a bandgap corresponding to a desired wavelength. Refractive indexes of the lower cladding layer 102 and upper cladding layer 104 are equal to or less than a refractive index of InP.
    Type: Application
    Filed: February 8, 2019
    Publication date: December 24, 2020
    Inventors: Tatsurou Hiraki, Takaaki Kakitsuka, Shinji Matsuo
  • Optical modulator
    Patent number: 10775650
    Abstract: An optical modulator includes a p-type first semiconductor layer (102) formed on a clad layer (101), an insulating layer (103) formed on the first semiconductor layer (102), and an n-type second semiconductor layer (104) formed on the insulating layer (103). The first semiconductor layer (102) is made of silicon or silicon-germanium, and the second semiconductor layer (104) is formed from a III-V compound semiconductor made of three or more materials.
    Type: Grant
    Filed: August 25, 2017
    Date of Patent: September 15, 2020
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Tatsurou Hiraki, Shinji Matsuo
  • OPTICAL MODULATOR
    Publication number: 20190187494
    Abstract: An optical modulator includes a p-type first semiconductor layer (102) formed on a clad layer (101), an insulating layer (103) formed on the first semiconductor layer (102), and an n-type second semiconductor layer (104) formed on the insulating layer (103). The first semiconductor layer (102) is made of silicon or silicon-germanium, and the second semiconductor layer (104) is formed from a III-V compound semiconductor made of three or more materials.
    Type: Application
    Filed: August 25, 2017
    Publication date: June 20, 2019
    Inventors: Tatsurou HIRAKI, Shinji MATSUO