Patents by Inventor Kazuhide Nakajima

Kazuhide Nakajima 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: 12203847
    Abstract: A shape measurement system and method for a three-dimensional shape of a linear object over a long distance with high resolution. The shape measurement system comprises: a multicore optical fiber having a center core positioned in the center of the cross section thereof and three or more outer peripheral cores positioned at equal intervals concentrically with respect to and outside of the center core; a measurement device for measuring the backward Brillouin scattered light distribution in the propagation direction of each core of the multicore optical fiber; and an analysis device for calculating position coordinates, in three-dimensional space, of a linear structure having an unknown three-dimensional shape from the backward Brillouin scattered light distributions of a multicore optical fiber positioned along the linear structure having an unknown three-dimensional shape and a multicore optical fiber positioned along a linear structure having a known three-dimensional shape.
    Type: Grant
    Filed: June 3, 2021
    Date of Patent: January 21, 2025
    Assignees: NIPPON TELEGRAPH AND TELEPHONE CORPORATION, THE UNIVERSITY OF TOKYO
    Inventors: Nobutomo Hanzawa, Kazuhide Nakajima, Takashi Matsui, Hideaki Murayama, Ryota Wada, Makito Kobayashi
  • Patent number: 12189178
    Abstract: The optical fiber according to the present invention includes, in a cross section of the optical fiber, one core region (11) and a cladding region (12) that is arranged on an outer periphery of the core region. The cladding region is a medium that has a lower refractive index than that of the core region and also has a smaller refractive index wavelength dispersion than that of the core region. The optical fiber has a solid core and therefore, allows more reduction in the Rayleigh scattering loss compared to an optical fiber having a hollow core. In addition, since the optical fiber adopts, for the cladding region, a medium that has a smaller refractive index wavelength dispersion than that of the core region, it allows a reduction in the wavelength dispersion of neff.
    Type: Grant
    Filed: June 3, 2020
    Date of Patent: January 7, 2025
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Yuto Sagae, Takashi Matsui, Kazuhide Nakajima
  • Publication number: 20250001036
    Abstract: An object of the present invention is to provide an air conditioner unit that can fully demonstrate the sterilization effect on air with a large flow rate, even by a method of irradiating a filter and a coil with ultraviolet light. The air conditioner unit according to the present invention includes a filter 20 through which air passes, a plurality of optical fibers 16 arranged in such a manner that one ends thereof are close to a surface of the filter 20 and arranged at predetermined intervals, and a light source 30 that supplies ultraviolet light from the other end of each of the optical fibers 16. Since the intensity of the light is inversely proportional to the square of the distance from the light source, if the same sterilization effect is to be obtained, the shorter the irradiation distance, the smaller the irradiation intensity of the ultraviolet light can be.
    Type: Application
    Filed: September 30, 2021
    Publication date: January 2, 2025
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Asuka MIYAKE, Hitoshi SISHIMO, Ryuji YAMAMOTO, Tomohiro TANIGUCHI, Ayako IWAKI, Satoshi NARIKAWA, Takahito KIRIHARA, Kazuhide NAKAJIMA, Takashi MATSUI, Yuto SAGAE, Chisato FUKAI, Nobutomo HANZAWA
  • Publication number: 20250004214
    Abstract: An object of the present invention is to provide an optical transmission system capable of reducing system costs and reducing waste of output power of a light source. The optical transmission system according to the present invention includes an ultraviolet light source part 11a having a light emitting diode (LED) that outputs ultraviolet light, an optical transmission line 26 that propagates the ultraviolet light through a plurality of cores of a multi-core optical fiber or a plurality of cores of a bundle optical fiber obtained by bundling a plurality of single-core optical fibers, and an optical system 11c that narrows down a spot shape of the ultraviolet light output from the LED to a size including all of the plurality of cores in an optical axis direction, and causes the ultraviolet light to enter the plurality of cores.
    Type: Application
    Filed: November 10, 2022
    Publication date: January 2, 2025
    Inventors: Takahito KIRIHARA, Satoshi Narikawa, Katsuhisa TAGUCHI, Ayako IWAKI, Kazuhide Nakajima, Takashi Matsui, Chisato Fukai, Yuto SAGAE, Tomohiro TANIGUCHI, Hiroyuki IIDA
  • Patent number: 12181706
    Abstract: An object is to provide a multi-core configuration for acquiring a random mode coupling in a case of an arbitrary core refractive index. A multi-core optical fiber according to the present invention is an optical fiber in which two or more core regions are arranged in a clad region having a refractive index at a minimum core interval ? smaller than a refractive index of the cores, a configuration of the cores is that including one propagation mode, and the core configuration and the core interval are adjusted so that an inter-mode coupling coefficient between adjacent cores is within a range from 0.73 to 120 m?1.
    Type: Grant
    Filed: April 6, 2020
    Date of Patent: December 31, 2024
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Taiji Sakamoto, Kazuhide Nakajima, Masaki Wada, Shinichi Aozasa, Takashi Yamamoto
  • Patent number: 12181707
    Abstract: The present invention is to provide a multi-core optical fiber that can expand its transmission wavelength band, and extend its transmission distance by reducing crosstalk, and also provide a method for designing the multi-core optical fiber. A multi-core optical fiber according to the present invention includes: four cores that are arranged in a square lattice pattern in a longitudinal direction; and a cladding region that is formed around the outer peripheral portions of the cores and has a lower refractive index than the cores, the absolute value of the relative refractive index difference between the cores and the cladding region being represented by A. In the multi-core optical fiber, the diameter of the cladding region is 125+1 ?m, the cutoff wavelength is 1.45 ?m or shorter, the mode field diameter MFD at a wavelength of 1.55 ?m is 9.5 to 10.0 ?m, the bending loss at a wavelength of 1.625 ?m and with a bending radius of 30 mm is 0.
    Type: Grant
    Filed: August 12, 2020
    Date of Patent: December 31, 2024
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Takashi Matsui, Kazuhide Nakajima, Taiji Sakamoto, Yuto Sagae
  • Publication number: 20240427078
    Abstract: There are provided a multi-core optical fiber including four step-index type cores with a standard cladding diameter and having excellent mass productivity, quality, and yield while meeting desired specifications, and a design method thereof. A multi-core optical fiber according to the present disclosure includes: four cores arranged in a square lattice shape along a longitudinal direction, each of the four cores having a step-index type refractive index distribution with a radius a; and a cladding region having a lower refractive index than that of each core and a diameter of 125±1 ?m and provided on an outer peripheral portion of each core, where an absolute value of a relative refractive index difference between each core and the cladding region is ?.
    Type: Application
    Filed: September 3, 2024
    Publication date: December 26, 2024
    Inventors: Takashi Matsui, Kazuhide Nakajima
  • Publication number: 20240427084
    Abstract: The present disclosure aims to provide a short optical fiber-type mode converter having small wavelength dependency. The present disclosure is about a mode converter including a cladding having a constant refractive index, a core having a refractive index higher than the refractive index of the cladding in the cladding, and a refractive index modulation part provided to obliquely cross the core and having a different refractive index from a refractive index of surroundings.
    Type: Application
    Filed: October 28, 2021
    Publication date: December 26, 2024
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Yoko YAMASHITA, Takayoshi MORI, Takashi MATSUI, Kazuhide NAKAJIMA
  • Patent number: 12174413
    Abstract: Provided are an LPFG and an optical transmission system in which a mode conversion amount does not depend on a polarization state and an electric field distribution. The LPFG according to the present invention includes cavity rows (25-1 and 25-2) of cavities 15 periodically arranged in a core region 11 of the few-mode fiber 10 at a position away from a central axis z of the core region 11 in parallel with the central axis z. Each of the cavity rows (25-1 and 25-2) is located at a different position in a longitudinal direction of the few-mode fiber 10 (where the position in a z direction is different), and the cavity rows (25-1 and 25-2) are located at positions shifted by 90° on a cross section of the core region 11 with the center of the cross section of the core region 11 (the intersection of an x-axis and a y-axis) as an origin.
    Type: Grant
    Filed: September 9, 2020
    Date of Patent: December 24, 2024
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Ryota Imada, Yoko Yamashita, Takashi Matsui, Taiji Sakamoto, Nobutomo Hanzawa, Noriyuki Araki, Shinichi Aozasa, Yuto Sagae, Kazuhide Nakajima
  • Publication number: 20240418073
    Abstract: The present disclosure is a control system configured to: collect a strain distribution of an underwater structure connected to an above-water structure; and control at least one of the underwater structure and the above-water structure in accordance with the strain distribution.
    Type: Application
    Filed: November 29, 2022
    Publication date: December 19, 2024
    Applicants: NIPPON TELEGRAPH AND TELEPHONE CORPORATION, THE UNIVERSITY OF TOKYO
    Inventors: Nobutomo HANZAWA, Kazuhide NAKAJIMA, Takashi MATSUI, Hideaki MURAYAMA, Ryota WADA
  • Patent number: 12158607
    Abstract: A mode loss difference compensator of the present disclosure includes a main waveguide configured to allow propagation of N or more modes (where N is an integer of 3 or more), a first auxiliary waveguide having, at one end thereof, a first coupling portion configured to mode-convert an LP0n mode (where n is an integer of 2 or more) propagating in the main waveguide into a fundamental mode in the first auxiliary waveguide and transfer the fundamental mode from the main waveguide to the first auxiliary waveguide and having, at the other end thereof, a second coupling portion configured to mode-convert the fundamental mode propagating in the first auxiliary waveguide into the LP0n mode (where n is an integer of 2 or more) in the main waveguide and transfer the LP0n mode from the first auxiliary waveguide to the main waveguide, and a second auxiliary waveguide having, at one end thereof, a third coupling portion configured to convert a higher-order mode, other than any LP0n mode (where n is an integer of 2 or mor
    Type: Grant
    Filed: April 24, 2020
    Date of Patent: December 3, 2024
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Yoko Yamashita, Takashi Matsui, Kazuhide Nakajima
  • Publication number: 20240390535
    Abstract: An object of the present invention is to provide an ultraviolet light irradiation sheet that can be decontaminated regardless of a shape of an object to be decontaminated. An ultraviolet light irradiation sheet (50) includes an optical fiber (20) which emits a part of propagating light from a side surface or an end surface; and a deformable sheet (10) which incorporates the optical fiber (20). The ultraviolet light irradiation sheet uniformly or partially irradiates ultraviolet light from a sheet surface. Therefore, by covering the object to be sterilized with the ultraviolet light irradiation sheet, a material having a complicated shape or an amorphous shape can be irradiated with the ultraviolet light without making a shade. Since the ultraviolet light irradiation sheet does not diffuse bacteria and viruses by wind, the sterilization of the object to be sterilized can be performed without forming a closed space.
    Type: Application
    Filed: September 30, 2021
    Publication date: November 28, 2024
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Asuka MIYAKE, Hitoshi SESHIMO, Ryuji YAMAMOTO, Tomohiro TANIGUCHI, Ayako IWAKI, Satoshi NARIKAWA, Takahito KIRIHARA, Kazuhide NAKAJIMA, Takashi MATSUI, Yuto SAGAE, Chisato FUKAI, Nobutomo HANZAWA
  • Publication number: 20240378937
    Abstract: An object of the present invention is to provide a banknote disinfection system configured to disinfect banknotes in a general-purpose banknote handling device without making a significant change in the structure of the general-purpose device. The banknote disinfection system 300 includes a conveyance mechanism configured to convey a banknote 50 using a plurality of rollers 12 and an optical fiber 20 configured to emit ultraviolet light to a surface of the banknote 50 conveyed by the conveyance mechanism. An optical fiber is thin, has many length options, and is flexible. With these features of the optical fiber, the optical fiber can be routed inside of, for example, an automatic teller machine to irradiate the banknotes moving inside the device with ultraviolet light.
    Type: Application
    Filed: September 24, 2021
    Publication date: November 14, 2024
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Asuka MIYAKE, Hitoshi SESHIMO, Ryuji YAMAMOTO, Tomohiro TANIGUCHI, Ayako IWAKI, Satoshi NARIKAWA, Takahito KIRIHARA, Kazuhide NAKAJIMA, Takashi MATSUI, Yuto SAGAE, Chisato FUKAI, Nobutomo HANZAWA
  • Publication number: 20240375093
    Abstract: An object of the present invention is to provide a photocatalytic sheet configured to perform disinfection independent of the state of external light. A photocatalytic sheet 50 according to the present invention includes a sheet 10 having a photocatalytic layer 17 on one surface, and an optical fiber 20 embedded in the sheet 10 and configured to supply ultraviolet light UV from inside of the sheet 10 to the photocatalytic layer 17. In the photocatalytic sheet, ultraviolet light is supplied from the optical fiber disposed in the sheet to the photocatalytic layer coated on the surface of the sheet (ultraviolet light is supplied from the back of the photocatalytic layer). This configuration allows for disinfection independent of the state of external light.
    Type: Application
    Filed: September 24, 2021
    Publication date: November 14, 2024
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Asuka MIYAKE, Hitoshi SESHIMO, Ryuji YAMAMOTO, Tomohiro TANIGUCHI, Ayako IWAKI, Satoshi NARIKAWA, Takahito KIRIHARA, Kazuhide NAKAJIMA, Takashi MATSUI, Yuto SAGAE, Chisato FUKAI, Nobutomo HANZAWA
  • Publication number: 20240369769
    Abstract: An object of the present disclosure is to provide an optical side input/output circuit for allowing light for being input into or output from a side surface of an optical fiber with high efficiency. The present disclosure is an optical side input/output circuit including: a tap unit in which a tap waveguide is formed for allowing light for propagation through a core of an optical fiber for being input into or output from a side surface of the optical fiber; and a refractive index matching unit, having a refractive index higher than a refractive index of the tap waveguide, on the side surface of the optical fiber where the light is allowed for being input or output by the tap waveguide.
    Type: Application
    Filed: June 28, 2021
    Publication date: November 7, 2024
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Yoko YAMASHITA, Takayoshi MORI, Takashi MATSUI, Kazuhide NAKAJIMA
  • Publication number: 20240361551
    Abstract: An object of the present invention is to ensure low crosstalk for all multi-core optical fibers in an optical fiber cable having a plurality of identical multi-core optical fibers of non-coupling type in different spiral shapes. An optical fiber cable according to the present disclosure is an optical fiber cable formed by twisting a plurality of units each of which is formed by bundling a plurality of identical multi-core optical fibers of non-coupling type, which includes: that all the units have the same diameter; that the units are arranged in a plurality of layers from a center in a cross section; that the units are arranged in a spiral shape for each of the layers in a longitudinal direction; that all the units included in one of the layers have the same twist pitch of the spiral shape; and that the twist pitch is different for each layer, and is set based on a curvature Rpk of the multi-core optical fiber where crosstalk is the largest.
    Type: Application
    Filed: August 19, 2021
    Publication date: October 31, 2024
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Yusuke YAMADA, Kazuhide NAKAJIMA
  • Patent number: 12117645
    Abstract: A multi-core optical fiber includes four cores arranged in a shape along a longitudinal direction, each of the four cores having a step-index type refractive index distribution with a radius, and a cladding region having a lower refractive index than that of each core and a diameter of 125±1 ?m and provided on an outer portion of each core. An absolute value of a relative refractive index difference between each core and the cladding region is ?. The four cores are arranged so that a relationship between a minimum distance from the center of each core to an outer periphery of the cladding region, a minimum value A of spacing between the cores, and the MFD at a set wavelength satisfies a Formula C1, and the radius of each core and the relative refractive index difference ? between the core and the cladding region are set.
    Type: Grant
    Filed: August 10, 2023
    Date of Patent: October 15, 2024
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Takashi Matsui, Kazuhide Nakajima
  • Publication number: 20240335578
    Abstract: An object of the present invention is to provide an ultraviolet light irradiation system that is easy to operate and can avoid degradation of a material due to ultraviolet light. An ultraviolet light irradiation system according to the present invention includes: one ultraviolet light source unit 11 that generates ultraviolet light; an irradiation unit 13 that irradiates a desired portion (irradiation portion ste) with the ultraviolet light in a limited manner; an optical fiber 14 that propagates the ultraviolet light from the ultraviolet light source unit 11 to the irradiation unit 13; a sensing unit 16 that monitors a state of the irradiation portion ste and outputs the state as monitoring information; and an irradiation control unit 15 that controls output of the ultraviolet light from the ultraviolet light source unit 11 on the basis of the monitoring information.
    Type: Application
    Filed: July 2, 2021
    Publication date: October 10, 2024
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Tomohiro TANIGUCHI, Ayako IWAKI, Satoshi NARIKAWA, Takahito KIRIHARA, Kazuhide NAKAJIMA, Takashi MATSUI, Nobutomo HANZAWA, Yuto SAGAE, Chisato FUKAI, Hitoshi SESHIMO, Ryuji YAMAMOTO, Asuka MIYAKE
  • Patent number: 12085749
    Abstract: The purpose of the present invention is to provide an optical fiber evaluation equipment and an optical fiber evaluation method that evaluate the center of a cladding of an MCF and a deviation of the center of each core of the MCF from a design value with ease and high accuracy. The optical fiber evaluation equipment according to the present invention approximates the outside diameter of a cladding by a circle, based on a cross-sectional image of an MCF, and determines the center of the circle as the center of the cladding. In addition, the optical fiber evaluation equipment according to the present invention obtains the center coordinates of cores with an origin at the center of the circle, rotates the cross-sectional image so as to minimize a difference between the center coordinates and design coordinates of each core, and derives the minimum value thereof as the amount of deviation of the center of each core.
    Type: Grant
    Filed: June 24, 2020
    Date of Patent: September 10, 2024
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Nobutomo Hanzawa, Takashi Matsui, Yuto Sagae, Kazuhide Nakajima
  • Publication number: 20240277886
    Abstract: An object of the present invention is to provide an air conditioner unit that allows for greater flexibility in designing the shape of the unit and is capable of reducing the cost of lamp replacement. An air conditioner unit according to the present invention includes an optical fiber group 17 formed by bundling a plurality of optical fibers 16 emitting a part of propagating light from side faces thereof; an air duct 10 that incorporates the optical fiber group 17 in a space 13 through which air passes; and a light source 30 that supplies ultraviolet light to each of the optical fibers 16. Since the intensity of the light is inversely proportional to the square of the distance from the light source, if the same sterilization effect is to be obtained, the irradiation intensity of the ultraviolet light can be reduced when the irradiation distance is shorter.
    Type: Application
    Filed: September 30, 2021
    Publication date: August 22, 2024
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Asuka MIYAKE, Hitoshi SESHIMO, Ryuji YAMAMOTO, Tomohiro TANIGUCHI, Ayako IWAKI, Satoshi NARIKAWA, Takahito KIRIHARA, Kazuhide NAKAJIMA, Takashi MATSUI, Yuto SAGAE, Chisato FUKAI, Nobutomo HANZAWA