Patents by Inventor Shinji Iwatsuka

Shinji Iwatsuka 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: 11003044
    Abstract: An electro-optic device is provided with a Mach-Zehnder optical waveguide including at least one linear section and at least one curved section and a differential RF signal electrode provided along the Mach-Zehnder optical waveguide. Optical input/output ports of the Mach-Zehnder optical waveguide are provided at one end side in a first direction in which the linear section extends. The differential RF signal electrode is provided in both the linear and curved sections.
    Type: Grant
    Filed: February 24, 2020
    Date of Patent: May 11, 2021
    Assignees: TDK CORPORATION, FUJITSU OPTICAL COMPONENTS LIMITED
    Inventors: Hiroki Hara, Shinji Iwatsuka, Takashi Kikukawa, Toshinori Matsuura, Yasuhiro Ohmori, Masaharu Doi, Shintaro Takeuchi, Yoshinobu Kubota
  • Patent number: 11003043
    Abstract: An optical modulator is provided with a ridge-shaped optical waveguide formed of a dielectric thin film having electro-optic effect, a buffer layer covering the optical waveguide, a signal electrode formed on the buffer layer so as to be opposed to the optical waveguide through the buffer layer; a ground electrode formed on the buffer layer together with the signal electrode, and a dielectric film having a higher dielectric constant than air and covering at least a part of exposed surfaces of the signal electrode and ground electrode and exposed surfaces of the buffer layer.
    Type: Grant
    Filed: February 24, 2020
    Date of Patent: May 11, 2021
    Assignee: TDK CORPORATION
    Inventors: Yasuhiro Ohmori, Masaharu Doi, Shintaro Takeuchi, Takehito Tanaka, Yoshinobu Kubota, Shinji Iwatsuka, Kenji Endou, Hiroki Hara, Toshinori Matsuura, Takashi Kikukawa
  • Patent number: 10989980
    Abstract: An optical modulator is provided with a substrate, first and second optical waveguides each formed of a ridge-shaped electro-optic material film and disposed so as to be mutually adjacent on the substrate, a buffer layer covering upper surfaces of the first and second optical waveguides, first and second signal electrodes provided above the buffer layer so as to be opposed respectively to the first and second optical waveguides, and a dielectric layer covering at least one of a part of an exposed surface of the first signal electrode and a part of an exposed surface of the second signal electrode, and a part of an upper surface of the buffer layer. Differential signals are applied to the first and second signal electrodes.
    Type: Grant
    Filed: February 24, 2020
    Date of Patent: April 27, 2021
    Assignees: TDK CORPORATION, FUJITSU OPTICAL COMPONENTS LIMITED
    Inventors: Shinji Iwatsuka, Kenji Endou, Hiroki Hara, Toshinori Matsuura, Takashi Kikukawa, Yasuhiro Ohmori, Masaharu Doi, Shintaro Takeuchi, Takehito Tanaka, Yoshinobu Kubota
  • Publication number: 20210103165
    Abstract: An electro-optic device is provided with a substrate, an optical waveguide formed of a lithium niobate film with a ridge shape on the substrate, and an electrode that applies an electric field to the optical waveguide. The optical waveguide includes a modulation waveguide provided in an electric field application region applied with the electric field and having a thickness of 1 ?m or larger and a bent waveguide provided in a region other than the electric field application region and having a curvature radius of 16 ?m or larger and 80 ?m or smaller.
    Type: Application
    Filed: March 27, 2020
    Publication date: April 8, 2021
    Inventors: Shinji IWATSUKA, Kenji SASAKI, Hiroki HARA, Yasuhiro OHMORI, Masaharu DOI, Shintaro TAKEUCHI, Yoshihiko YOSHIDA, Yoshinobu KUBOTA
  • Patent number: 10955722
    Abstract: An object of the present invention is to provide a single drive type optical modulator having good high-frequency characteristics and reduced wavelength chirp of the modulated light.
    Type: Grant
    Filed: February 5, 2020
    Date of Patent: March 23, 2021
    Assignee: TDK CORPORATION
    Inventors: Shinji Iwatsuka, Kenji Sasaki
  • Publication number: 20200310170
    Abstract: An optical modulator includes: a substrate; a waveguide layer including first and second optical waveguides formed of an electro-optic material film on the substrate to have a ridge shape and to be disposed adjacent to each other; an RF part that applies a modulated signal to the optical waveguides; and a DC part that applies a DC bias to the optical waveguides. The DC part includes: a buffer layer covering at least upper surfaces of the optical waveguides; a first bias electrode opposed to the first optical waveguide through the buffer layer; and a second bias electrode provided adjacent to the first bias electrode. A first DC bias voltage is applied between the first and second bias electrodes. A waveguide layer removal area in which at least part of the waveguide layer is removed is provided at least under an area between the first and second bias electrodes.
    Type: Application
    Filed: September 28, 2018
    Publication date: October 1, 2020
    Inventors: Shinji IWATSUKA, Makoto ENDO, Kenji SASAKI
  • Publication number: 20200310216
    Abstract: An electro-optic device is provided with a substrate, an optical waveguide formed of a lithium niobate film with a ridge shape on the substrate, and an electrode that applies an electric field to the optical waveguide. The optical waveguide includes a first waveguide section provided at least in an electric field application region applied with the electric field and having a thickness of 1 ?m or larger and a second waveguide section provided in a region other than the electric field application region and having a thickness of 0.3 ?m or larger and less than 1 ?m.
    Type: Application
    Filed: March 27, 2020
    Publication date: October 1, 2020
    Inventors: Shinji IWATSUKA, Kenji SASAKI, Hiroki HARA, Yasuhiro OHMORI, Masaharu DOI, Shintaro TAKEUCHI, Yoshihiko YOSHIDA, Yoshinobu KUBOTA
  • Publication number: 20200272020
    Abstract: An optical modulator is provided with a ridge-shaped optical waveguide formed of a dielectric thin film having electro-optic effect, a buffer layer covering the optical waveguide, a signal electrode formed on the buffer layer so as to be opposed to the optical waveguide through the buffer layer; a ground electrode formed on the buffer layer together with the signal electrode, and a dielectric film having a higher dielectric constant than air and covering at least a part of exposed surfaces of the signal electrode and ground electrode and exposed surfaces of the buffer layer.
    Type: Application
    Filed: February 24, 2020
    Publication date: August 27, 2020
    Inventors: Yasuhiro OHMORI, Masaharu DOI, Shintaro TAKEUCHI, Takehito TANAKA, Yoshinobu KUBOTA, Shinji IWATSUKA, Kenji ENDOU, Hiroki HARA, Toshinori MATSUURA, Takashi KIKUKAWA
  • Publication number: 20200272021
    Abstract: An electro-optic device is provided with a Mach-Zehnder optical waveguide including at least one linear section and at least one curved section and a differential RF signal electrode provided along the Mach-Zehnder optical waveguide. Optical input/output ports of the Mach-Zehnder optical waveguide are provided at one end side in a first direction in which the linear section extends. The differential RF signal electrode is provided in both the linear and curved sections.
    Type: Application
    Filed: February 24, 2020
    Publication date: August 27, 2020
    Applicant: FUJITSU OPTICAL COMPONENTS LIMITED
    Inventors: Hiroki HARA, Shinji IWATSUKA, Takashi KIKUKAWA, Toshinori MATSUURA, Yasuhiro OHMORI, Masaharu DOI, Shintaro TAKEUCHI, Yoshinobu KUBOTA
  • Publication number: 20200271963
    Abstract: An optical modulator is provided with a substrate, first and second optical waveguides each formed of a ridge-shaped electro-optic material film and disposed so as to be mutually adjacent on the substrate, a buffer layer covering upper surfaces of the first and second optical waveguides, first and second signal electrodes provided above the buffer layer so as to be opposed respectively to the first and second optical waveguides, and a dielectric layer covering at least one of a part of an exposed surface of the first signal electrode and a part of an exposed surface of the second signal electrode, and a part of an upper surface of the buffer layer. Differential signals are applied to the first and second signal electrodes.
    Type: Application
    Filed: February 24, 2020
    Publication date: August 27, 2020
    Inventors: Shinji Iwatsuka, Kenji Endou, Hiroki Hara, Toshinori Matsuura, Takashi Kikukawa, Yasuhiro Ohmori, Masaharu Doi, Shintaro Takeuchi, Takehito Tanaka, Yoshinobu Kubota
  • Publication number: 20200218126
    Abstract: An optical modulator includes: first and second optical waveguides formed of an electro-optic material film on a substrate so as to have a ridge shape and to be disposed adjacent to each other; a buffer layer covering at least the upper surfaces of the first and second optical waveguides; and first and second signal electrodes provided above the buffer layer. The first and second signal electrodes have, respectively, first and second lower layer parts opposite, respectively, to the first and second optical waveguides through the buffer layer; and first and second upper layer parts provided, respectively, above the first and second lower layer parts. Widths of the lower surfaces of the first and second lower layer parts are smaller than widths of the first and second upper layer parts.
    Type: Application
    Filed: July 31, 2018
    Publication date: July 9, 2020
    Inventors: Shinji IWATSUKA, Makoto ENDO, Kenji SASAKI
  • Publication number: 20200174337
    Abstract: An object of the present invention is to provide a single drive type optical modulator having good high-frequency characteristics and reduced wavelength chirp of the modulated light.
    Type: Application
    Filed: February 5, 2020
    Publication date: June 4, 2020
    Applicant: TDK CORPORATION
    Inventors: Shinji IWATSUKA, Kenji Sasaki
  • Patent number: 10649246
    Abstract: A dielectric thin film-applied substrate that suppresses occurrence of cracks when the film thickness of the lithium niobate film is equal to or larger than 1 ?m. The dielectric thin film-applied substrate includes a single crystal substrate and a dielectric thin film made of c-axis oriented lithium niobate epitaxially formed on a main surface of the single crystal substrate. The dielectric thin film has a twin crystal structure including first and second crystals 180° apart, centered on the c-axis. In pole figure measurement by X-ray diffraction, the ratio between a first diffraction intensity corresponding to the first crystal and a second diffraction intensity corresponding to the second crystal is equal to or higher than 0.5 and equal to or lower than 2.0, which alleviates distortions accumulated inside the lithium niobate film and supresses occurrences of cracks accompanying increases in the film thickness.
    Type: Grant
    Filed: July 14, 2017
    Date of Patent: May 12, 2020
    Assignee: TDK CORPORATION
    Inventors: Kenji Sasaki, Shinji Iwatsuka
  • Patent number: 10591801
    Abstract: A single drive type optical modulator has good high-frequency characteristics and reduced wavelength chirp of the modulated light. An optical modulator is provided with a Mach-Zehnder optical waveguide including first and second optical waveguides, a buffer layer covering the first and second optical waveguides, and an electrode layer including first and second ground electrodes and a signal electrode positioned between the first and second ground electrodes in a plan view. The signal electrode has a first lower surface covering the first optical waveguide through the buffer layer, the first ground electrode has a first lower surface covering the second optical waveguide through the buffer layer and a second lower surface positioned above the first lower surface, and a gap between the signal electrode and the second ground electrode that is larger than a gap between the signal electrode and the first ground electrode.
    Type: Grant
    Filed: April 7, 2017
    Date of Patent: March 17, 2020
    Assignee: TDK CORPORATION
    Inventors: Shinji Iwatsuka, Kenji Sasaki
  • Patent number: 10585328
    Abstract: Disclosed herein is an optical waveguide element that includes a substrate and a waveguide layer formed on the substrate and comprising lithium niobate. The waveguide layer has a slab part having a predetermined thickness and a ridge part protruding from the slab part. The maximum thickness of the slab part is 0.05 times or more and less than 0.4 times a wavelength of a light propagating in the ridge part.
    Type: Grant
    Filed: May 13, 2019
    Date of Patent: March 10, 2020
    Assignee: TDK CORPORATION
    Inventors: Shinji Iwatsuka, Kenji Sasaki, Satoshi Shirai
  • Publication number: 20190293972
    Abstract: A dielectric thin film-applied substrate capable of suppressing occurrence of cracks even when the film thickness of the lithium niobate film is made, e.g., equal to or larger than 1 ?m. The dielectric thin film-applied substrate includes a single crystal substrate and a dielectric thin film which is made of c-axis oriented lithium niobate and epitaxially formed on a main surface of the single crystal substrate. The dielectric thin film has a twin crystal structure including a first and crystals existing at a position obtained by rotating the first crystal 180° centered on the c-axis. In pole figure measurement by an X-ray diffraction method, the ratio between a first diffraction intensity corresponding to the first crystal and a second diffraction intensity corresponding to the second crystal is equal to or higher than 0.5 and equal to or lower than 2.0.
    Type: Application
    Filed: July 14, 2017
    Publication date: September 26, 2019
    Applicant: TDK CORPORATION
    Inventors: Kenji SASAKI, Shinji IWATSUKA
  • Publication number: 20190271897
    Abstract: Disclosed herein is an optical waveguide element that includes a substrate and a waveguide layer formed on the substrate and comprising lithium niobate. The waveguide layer has a slab part having a predetermined thickness and a ridge part protruding from the slab part. The maximum thickness of the slab part is 0.05 times or more and less than 0.4 times a wavelength of a light propagating in the ridge part.
    Type: Application
    Filed: May 13, 2019
    Publication date: September 5, 2019
    Applicant: TDK Corporation
    Inventors: Shinji IWATSUKA, Kenji SASAKI, Satoshi SHIRAI
  • Patent number: 10359684
    Abstract: Disclosed herein is an optical waveguide element that includes a substrate and a waveguide layer formed on the substrate and comprising lithium niobate. The waveguide layer has a slab part having a predetermined thickness and a ridge part protruding from the slab part. The maximum thickness of the slab part is 0.05 times or more and less than 0.4 times a wavelength of a light propagating in the ridge part.
    Type: Grant
    Filed: November 9, 2018
    Date of Patent: July 23, 2019
    Assignee: TDK CORPORATION
    Inventors: Shinji Iwatsuka, Kenji Sasaki, Satoshi Shirai
  • Publication number: 20190146302
    Abstract: A single drive type optical modulator has good high-frequency characteristics and reduced wavelength chirp of the modulated light. An optical modulator is provided with a Mach-Zehnder optical waveguide including first and second optical waveguides, a buffer layer covering the first and second optical waveguides, and an electrode layer including first and second ground electrodes and a signal electrode positioned between the first and second ground electrodes in a plan view. The signal electrode has a first lower surface covering the first optical waveguide through the buffer layer, the first ground electrode has a first lower surface covering the second optical waveguide through the buffer layer and a second lower surface positioned above the first lower surface, and a gap between the signal electrode and the second ground electrode that is larger than a gap between the signal electrode and the first ground electrode.
    Type: Application
    Filed: April 7, 2017
    Publication date: May 16, 2019
    Applicant: TDK CORPORATION
    Inventors: Shinji IWATSUKA, Kenji SASAKI
  • Publication number: 20190079366
    Abstract: Disclosed herein is an optical waveguide element that includes a substrate and a waveguide layer formed on the substrate and comprising lithium niobate. The waveguide layer has a slab part having a predetermined thickness and a ridge part protruding from the slab part. The maximum thickness of the slab part is 0.05 times or more and less than 0.4 times a wavelength of a light propagating in the ridge part.
    Type: Application
    Filed: November 9, 2018
    Publication date: March 14, 2019
    Applicant: TDK Corporation
    Inventors: Shinji IWATSUKA, Kenji Sasaki, Satoshi Shirai