Patents by Inventor Masafumi Nakada

Masafumi Nakada 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: 8654331
    Abstract: There is provided an electromagnetic field measurement apparatus capable of achieving correct and timely circuit operation detection in an area where electronic devices are mounted at high density. An electromagnetic field measurement apparatus includes: a laser light source; a polarized wave controller that linearly polarizes laser light; an optical fiber probe that has an electrooptic material or a magnetooptic material at its leading end and in which the laser light reflected at the leading end is subjected to polarization modulation in accordance with an electric field intensity or a magnetic field intensity; and an analyzer that converts the laser light reflected by the optical fiber probe into intensity modulated light. The laser light source emits time-multiplexed laser light of a plurality of wavelengths different from one another.
    Type: Grant
    Filed: February 4, 2009
    Date of Patent: February 18, 2014
    Assignee: NEC Corporation
    Inventors: Mizuki Iwanami, Tsuneo Tsukagoshi, Risato Ohhira, Masafumi Nakada, Tomonori Yamada
  • Patent number: 8519323
    Abstract: A magnetic field sensor fabrication method of directly forming, with an aerosol deposition method, at a tip of an optical fiber, a magnetooptical layer having a refractive index that changes depending on a magnetic field, the method includes establishing a relationship of dc?d?dr among a diameter d of the magnetooptical layer, a diameter dc of a core of the optical fiber, and a diameter dr of a clad thereof.
    Type: Grant
    Filed: March 5, 2012
    Date of Patent: August 27, 2013
    Assignee: NEC Corporation
    Inventors: Masafumi Nakada, Mizuki Iwanami, Keishi Oohashi, Norio Masuda
  • Patent number: 8515225
    Abstract: Provided is an optical device that includes a ring-shaped optical waveguide and an input/output optical waveguide, and that changes a resonant wavelength of the ring-shaped optical waveguide, in which the ring-shaped optical waveguide includes in part a refractive index control section for controlling a refractive index at a guided wavelength, and the refractive index control section is formed of an optical material having a thermo-optic effect with its sign different from that of an optical material that forms a section of the ring-shaped optical waveguide other than the refractive index control section.
    Type: Grant
    Filed: March 3, 2009
    Date of Patent: August 20, 2013
    Assignees: NEC Corporation, Kabushiki Kaisha Toshiba
    Inventors: Masafumi Nakada, Takanori Shimizu, Nobuo Suzuki
  • Patent number: 8358891
    Abstract: There is provided a waveguide type optical device whose parasitic capacitance is reduced to allow an increase in signal transmission speed. Bottom electrode 41 is formed on substrate 2, bottom cladding 51 is formed on bottom electrode 41, and bottom core 62 is formed on bottom cladding 51. Top core 61 is formed on bottom core 62, top cladding 53 is formed on top core 61, and top electrode 42 is formed on top cladding 53. Two sides of top core 61 and bottom core 62 are covered with side cladding layer 52. Vertically overlapping portions of top electrode 42 and bottom electrode 41 are located almost at a same place as a region for a core layer composed of top core 61 and bottom core 62. The width of one from among top core 61 and bottom core 62 is satisfying a single mode condition, and the width of the other is almost equal to or more than the width of a field distribution.
    Type: Grant
    Filed: November 20, 2008
    Date of Patent: January 22, 2013
    Assignee: NEC Corporation
    Inventors: Takanori Shimizu, Masafumi Nakada
  • Patent number: 8254745
    Abstract: At least part of an optical device comprises an optical waveguide of a magneto-optical material. The magneto-optical material comprises a polycrystalline material having no lattice matching with an underlayer material. The optical waveguide exhibits no magnetic anisotropy due to an inverse magnetostriction effect caused by thermal strain. The magnetization direction of the optical waveguide is aligned with a traveling direction of light passing through the waveguide by shape magnetic anisotropy.
    Type: Grant
    Filed: July 11, 2008
    Date of Patent: August 28, 2012
    Assignee: NEC Corporation
    Inventors: Masafumi Nakada, Takanori Shimizu
  • Patent number: 8233753
    Abstract: An electric field sensor or a magnetic field sensor includes an optical fiber and an electro-optic layer or a magneto-optic layer. The electro-optic layer or a magneto-optic layer is provided on an end surface of an end portion of the optical fiber. The end surface of the optical fiber is a convex shape. The optical fiber may have the end portion with a shape of a substantial cone formed by extending the end portion, and the electro-optic layer or the magneto-optic layer may be formed on a side surface of a front end of the substantial cone. A dielectric layer may be further included between the optic layer and the end surface.
    Type: Grant
    Filed: June 23, 2006
    Date of Patent: July 31, 2012
    Assignee: NEC Corporation
    Inventors: Mizuki Iwanami, Masafumi Nakada, Norio Masuda, Keishi Ohashi
  • Publication number: 20120164321
    Abstract: An electric field sensor is obtained by directly forming an electrooptical film of Fabry-Perot resonator structure on a polished surface at a tip of an optical fiber by an aerosol deposition method.
    Type: Application
    Filed: March 5, 2012
    Publication date: June 28, 2012
    Applicant: NEC CORPORATION
    Inventors: Masafumi NAKADA, Mizuki IWANAMI, Keishi OOHASHI, Norio MASUDA
  • Patent number: 8153955
    Abstract: An electric field sensor is obtained by directly forming an electrooptical film of Fabry-Perot resonator structure on a polished surface at a tip of an optical fiber by an aerosol deposition method.
    Type: Grant
    Filed: June 29, 2006
    Date of Patent: April 10, 2012
    Assignee: NEC Corporation
    Inventors: Masafumi Nakada, Mizuki Iwanami, Keishi Oohashi, Norio Masuda
  • Patent number: 8116600
    Abstract: Provided is a small-size optical phase modulation element and an optical modulator using it. The optical phase modulation element includes a Plasmon waveguide having a clad made of a metal material having a complex dielectric constant having a negative real part in the used wavelength and a core formed by a dielectric metal material having a complex dielectric constant having a positive real part in the used wavelength. The Plasmon waveguide is connected to an optical waveguide including a clad and a core both having a complex dielectric constant having a positive real part. The core of the Plasmon waveguide and the core of the optical waveguide are formed, at least partially, of the same semiconductor material. The Plasmon waveguide has a function to phase-modulate the incident light when voltage is applied.
    Type: Grant
    Filed: December 25, 2007
    Date of Patent: February 14, 2012
    Assignee: NEC Corporation
    Inventors: Daisuke Okamoto, Masafumi Nakada, Junichi Fujikata
  • Patent number: 7920769
    Abstract: In a compact formed by subjecting an ultrafine particle brittle material supplied on a substrate to mechanical impact force as a load, whereby the ultrafine particle brittle material is crushed and joined to each other, manganese is added into the ultrafine particle brittle material to form the compact.
    Type: Grant
    Filed: January 19, 2007
    Date of Patent: April 5, 2011
    Assignees: NEC Corporation, National Institute of Advanced Industrial Science and Technology
    Inventors: Masafumi Nakada, Jun Akedo
  • Publication number: 20110001971
    Abstract: There is provided an electromagnetic field measurement apparatus capable of achieving correct and timely circuit operation detection in an area where electronic devices are mounted at high density. An electromagnetic field measurement apparatus includes: a laser light source; a polarized wave controller that linearly polarizes laser light; an optical fiber probe that has an electrooptic material or a magnetooptic material at its leading end and in which the laser light reflected at the leading end is subjected to polarization modulation in accordance with an electric field intensity or a magnetic field intensity; and an analyzer that converts the laser light reflected by the optical fiber probe into intensity modulated light. The laser light source emits time-multiplexed laser light of a plurality of wavelengths different from one another.
    Type: Application
    Filed: February 4, 2009
    Publication date: January 6, 2011
    Inventors: Mizuki Iwanami, Tsuneo Tsukagoshi, Risato Ohhira, Masafumi Nakada, Tomonori Yamada
  • Publication number: 20110002578
    Abstract: Provided is an optical device that includes a ring-shaped optical waveguide and an input/output optical waveguide, and that changes a resonant wavelength of the ring-shaped optical waveguide, in which the ring-shaped optical waveguide includes in part a refractive index control section for controlling a refractive index at a guided wavelength, and the refractive index control section is formed of an optical material having a thermo-optic effect with its sign different from that of an optical material that forms a section of the ring-shaped optical waveguide other than the refractive index control section.
    Type: Application
    Filed: March 3, 2009
    Publication date: January 6, 2011
    Applicants: NEC CORPORATION, KABUSHIKI KAISHA TOSHIBA
    Inventors: Masafumi Nakada, Takanori Shimizu, Nobuo Suzuki
  • Publication number: 20100316325
    Abstract: Provided is a small-size optical phase modulation element and an optical modulator using it. The optical phase modulation element includes a Plasmon waveguide having a clad made of a metal material having a complex dielectric constant having a negative real part in the used wavelength and a core formed by a dielectric metal material having a complex dielectric constant having a positive real part in the used wavelength. The Plasmon waveguide is connected to an optical waveguide including a clad and a core both having a complex dielectric constant having a positive real part. The core of the Plasmon waveguide and the core of the optical waveguide are formed, at least partially, of the same semiconductor material. The Plasmon waveguide has a function to phase-modulate the incident light when voltage is applied.
    Type: Application
    Filed: December 25, 2007
    Publication date: December 16, 2010
    Inventors: Daisuke Okamoto, Masafumi Nakada, Junichi Fujikata
  • Publication number: 20100260461
    Abstract: There is provided a waveguide type optical device whose parasitic capacitance is reduced to allow an increase in signal transmission speed. Bottom electrode 41 is formed on substrate 2, bottom cladding 51 is formed on bottom electrode 41, and bottom core 62 is formed on bottom cladding 51. Top core 61 is formed on bottom core 62, top cladding 53 is formed on top core 61, and top electrode 42 is formed on top cladding 53. Two sides of top core 61 and bottom core 62 are covered with side cladding layer 52. Vertically overlapping portions of top electrode 42 and bottom electrode 41 are located almost at a same place as a region for a core layer composed of top core 61 and bottom core 62. The width of one from among top core 61 and bottom core 62 is satisfying a single mode condition, and the width of the other is almost equal to or more than the width of a field distribution.
    Type: Application
    Filed: November 20, 2008
    Publication date: October 14, 2010
    Inventors: Takanori Shimizu, Masafumi Nakada
  • Publication number: 20100158430
    Abstract: At least part of an optical device comprises an optical waveguide of a magneto-optical material. The magneto-optical material comprises a polycrystalline material having no lattice matching with an underlayer material. The optical waveguide exhibits no magnetic anisotropy due to an inverse magnetostriction effect caused by thermal strain. The magnetization direction of the optical waveguide is aligned with a traveling direction of light passing through the waveguide by shape magnetic anisotropy.
    Type: Application
    Filed: July 11, 2008
    Publication date: June 24, 2010
    Inventors: Masafumi Nakada, Takanori Shimizu
  • Publication number: 20090310903
    Abstract: In a compact formed by subjecting an ultrafine particle brittle material supplied on a substrate to mechanical impact force as a load, whereby the ultrafine particle brittle material is crushed and joined to each other, manganese is added into the ultrafine particle brittle material to form the compact.
    Type: Application
    Filed: January 19, 2007
    Publication date: December 17, 2009
    Inventors: Masafumi Nakada, Jun Akedo
  • Publication number: 20090234619
    Abstract: An electric field sensor or a magnetic field sensor includes an optical fiber and an electro-optic layer or a magneto-optic layer. The electro-optic layer or a magneto-optic layer is provided on an end surface of an end portion of the optical fiber. The end surface of the optical fiber is a convex shape. The optical fiber may have the end portion with a shape of a substantial cone formed by extending the end portion, and the electro-optic layer or the magneto-optic layer may be formed on a side surface of a front end of the substantial cone. A dielectric layer may be further included between the optic layer and the end surface.
    Type: Application
    Filed: June 23, 2006
    Publication date: September 17, 2009
    Applicant: NEC CORPORATION
    Inventors: Mizuki Iwanami, Masafumi Nakada, Norio Masuda, Keishi Ohashi
  • Publication number: 20090224753
    Abstract: An electric field sensor is obtained by directly forming an electrooptical film of Fabry-Perot resonator structure on a polished surface at a tip of an optical fiber by an aerosol deposition method.
    Type: Application
    Filed: June 29, 2006
    Publication date: September 10, 2009
    Applicant: NEC CORPORATION
    Inventors: Masafumi Nakada, Mizuki Iwanami, Keishi Oohashi, Norio Masuda
  • Patent number: 7372673
    Abstract: In a magnetoresistive effect transducer including a pinning layer, a pinned layer, a free layer and a non-magnetic layer inserted between the pinned layer and the free layer, a longitudinal bias layer is connected directly to a part of the free layer to apply a bias magnetic field to the free layer, thus biasing a magnetization direction of the free layer so that the magnetization direction of the free layer coincides with that of the longitudinal bias layer.
    Type: Grant
    Filed: May 31, 2005
    Date of Patent: May 13, 2008
    Assignee: NEC Corporation
    Inventors: Kazuhiko Hayashi, Keishi Ohashi, Nobuyuki Ishiwata, Masafumi Nakada, Tsutomu Ishi, Hiroaki Honjou, Kunihiko Ishihara, Jun-Ichi Fujikata, Hisao Matsutera, Hisanao Tsuge, Atsushi Kamijo
  • Patent number: 7369375
    Abstract: A magneto-resistance effect head is provided with a lower conductive layer which is provided with a recessed portion, and a vertical bias layer is provided in the recessed portion. A first magnetic layer is provided on the lower conductive layer. On the first magnetic layer, layered in the following order are the non-magnetic layer, the fixed layer, the fixing layer, and the upper layer so as not to be placed immediately above the vertical bias layer. The non-magnetic layer, the fixed layer, the fixing layer, and the upper layer are buried in an insulation layer. Furthermore, an upper conductive layer is provided on the upper layer and the insulation layer. In the direction of the magnetic field applied by the vertical bias layer, the free layer is made greater in length than the fixed layer and the free layer is disposed in proximity to the vertical bias layer with the distance between the fixed layer and the vertical bias layer remaining unchanged.
    Type: Grant
    Filed: June 30, 2006
    Date of Patent: May 6, 2008
    Assignee: NEC Corporation
    Inventors: Kazuhiko Hayashi, Junichi Fujikata, Tsutomu Ishi, Shigeru Mori, Keishi Ohashi, Masafumi Nakada, Kiyokazu Nagahara, Kunihiko Ishihara, Nobuyuki Ishiwata