Patents by Inventor Hitoshi Takeshita

Hitoshi Takeshita 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: 20220166179
    Abstract: It is difficult to construct an optical fiber transmission system enabling relay optical amplification using a coupled multi-core optical fiber as an optical transmission path; therefore, an optical amplification device includes first optical spatial layout converting means for converting a spatial layout of a plurality of optical signal beams propagating through each of a plurality of cores, from a coupled state in which optical signal beams interfere between a plurality of cores to a non-coupled state in which optical signal beam interference is reduced between a plurality of cores; optical amplifying means for amplifying, in the non-coupled state, the plurality of optical signal beams with the non-coupled state and generating a plurality of amplified optical signal beams; and second optical spatial layout converting means for converting a spatial layout of the plurality of amplified optical signal beams from the non-coupled state to the coupled state.
    Type: Application
    Filed: April 2, 2020
    Publication date: May 26, 2022
    Applicant: NEC Corporation
    Inventors: Hitoshi TAKESHITA, Keiichi MATSUMOTO, Shigeyuki YANAGIMACHI
  • Publication number: 20220060257
    Abstract: If wavelength defragmentation is performed during the operation of an optical network, an instantaneous interruption of a network arises; consequently, data are lost; therefore, an optical network control method according to an exemplary aspect of the present invention includes monitoring a data volume of a client signal to be transmitted using a plurality of optical subcarriers; and performing synchronously, depending on a variation in the data volume, an optical subcarrier changing process of changing an active optical subcarrier, of the plurality of optical subcarriers, to be used for transmitting the client signal, and a remapping process of remapping the client signal onto an active optical subcarrier after having been changed.
    Type: Application
    Filed: November 5, 2021
    Publication date: February 24, 2022
    Applicant: NEC Corporation
    Inventors: Tomoyuki HINO, Akio Tajima, Hitoshi Takeshita, Shinsuke Fujisawa
  • Patent number: 11212027
    Abstract: This optical path setting device comprises: a transmission characteristic calculating means for calculating an inter-endpoint transmission characteristic that is a characteristic for transmission between endpoints of an optical path accommodating traffic in a plurality of optical communication systems; a required wavelength bandwidth determining means for determining a required wavelength bandwidth that is a wavelength bandwidth meeting an arrival performance of the optical path on the basis of the inter-endpoint transmission characteristic; and an accommodating wavelength band determining means for determining, as an accommodating wavelength band for accommodating the optical path, a common wavelength band that is a wavelength band where an optical path having the required wavelength bandwidth can be allocated, and that is common to the plurality of optical communication systems.
    Type: Grant
    Filed: November 29, 2018
    Date of Patent: December 28, 2021
    Assignee: NEC CORPORATION
    Inventors: Shinsuke Fujisawa, Hitoshi Takeshita, Shigeyuki Yanagimachi, Emmanuel Le Taillandier De Gabory
  • Publication number: 20210399514
    Abstract: An optical amplification apparatus includes an optical amplification medium, having a gain in a wavelength band of signal light, configured to receive the signal light; excitation light introduction means for introducing, into the optical amplification medium, excitation light to excite the optical amplification medium; and residual excitation light introduction means for introducing, into the optical amplification medium, residual excitation light output from the optical amplification medium, the residual excitation light having a wavelength component of the excitation light, wherein the residual excitation light introduction means includes, on a side of one end of the optical amplification medium, residual excitation light multiplexing means for multiplexing the signal light and the residual excitation light, and on a side of another end of the optical amplification medium, space propagation type wavelength demultiplexing means for wavelength-demultiplexing the signal light and the residual excitation light
    Type: Application
    Filed: September 27, 2019
    Publication date: December 23, 2021
    Applicant: NEC Corporation
    Inventors: Hitoshi TAKESHITA, Keiichi MATSUMOTO, Emmanuel LE TAILLANDIER DE GABORY
  • Patent number: 11201668
    Abstract: If wavelength defragmentation is performed during the operation of an optical network, an instantaneous interruption of a network arises; consequently, data are lost; therefore, an optical network control method according to an exemplary aspect of the present invention includes monitoring a data volume of a client signal to be transmitted using a plurality of optical subcarriers; and performing synchronously, depending on a variation in the data volume, an optical subcarrier changing process of changing an active optical subcarrier, of the plurality of optical subcarriers, to be used for transmitting the client signal, and a remapping process of remapping the client signal onto an active optical subcarrier after having been changed.
    Type: Grant
    Filed: June 17, 2020
    Date of Patent: December 14, 2021
    Assignee: NEC CORPORATION
    Inventors: Tomoyuki Hino, Akio Tajima, Hitoshi Takeshita, Shinsuke Fujisawa
  • Publication number: 20210352386
    Abstract: It is difficult to improve the usage efficiency of an optical communication network due to the passband narrowing effect in a wavelength selection process in an optical communication network using a wavelength division multiplexing system; therefore, an optical network management apparatus according to an exemplary aspect of the present invention includes wavelength selection information generating means for generating wavelength selection information on a wavelength selection process through which an optical path accommodating an information signal goes, with respect to each optical path; and wavelength selection information notifying means for notifying an optical node device through which the optical path goes of the wavelength selection information.
    Type: Application
    Filed: July 26, 2021
    Publication date: November 11, 2021
    Applicant: NEC CORPORATION
    Inventors: Hitoshi Takeshita, Shinsuke Fujisawa, Tomoyuki Hino, Akio Tajima
  • Patent number: 11115318
    Abstract: An optical network control device includes: a path setting unit that sets, based on topology information including a connection relationship among a plurality of nodes and a first route selection index value of routes each connecting the plurality of nodes, a first path for a route having the first route selection index value being minimum from among route candidates linking a start point node and an end point node of a requested traffic; a topology information modification unit that calculates a second route selection index value acquired by increasing the first route selection index value of the route that accommodates the first path; and a path selection unit that selects a second path for a route having the second route selection index value being minimum from among the route candidates.
    Type: Grant
    Filed: October 4, 2017
    Date of Patent: September 7, 2021
    Assignee: NEC CORPORATION
    Inventors: Shinsuke Fujisawa, Hitoshi Takeshita, Akio Tajima
  • Patent number: 11115117
    Abstract: A submarine optical communication system control device (1) according to the present invention includes: a light intensity distribution determination device (2) configured to determine an optimum distribution of signal light intensity of each optical path for each allocated frequency; a light intensity distribution measuring device (3) configured to measure a light intensity distribution of an optical path after transmission through a submarine cable transmission line; an equalization setting calculation unit (4) configured to calculate a gain equalization setting for compensating for the difference between an optimum distribution in the light intensity distribution determination device and a measured distribution in the light intensity distribution measuring device; and a variable gain equalizer (5) configured to compensate for a light intensity distribution of an optical path to the optimum distribution, based on a gain equalization setting in the equalization setting calculation unit.
    Type: Grant
    Filed: March 27, 2018
    Date of Patent: September 7, 2021
    Assignee: NEC CORPORATION
    Inventors: Shinsuke Fujisawa, Hitoshi Takeshita, Shigeyuki Yanagimachi, Emmanuel Le Taillandier De Gabory
  • Patent number: 11109123
    Abstract: It is difficult to improve the usage efficiency of an optical communication network due to the passband narrowing effect in a wavelength selection process in an optical communication network using a wavelength division multiplexing system; therefore, an optical network management apparatus according to an exemplary aspect of the present invention includes wavelength selection information generating means for generating wavelength selection information on a wavelength selection process through which an optical path accommodating an information signal goes, with respect to each optical path; and wavelength selection information notifying means for notifying an optical node device through which the optical path goes of the wavelength selection information.
    Type: Grant
    Filed: July 9, 2020
    Date of Patent: August 31, 2021
    Assignee: NEC CORPORATION
    Inventors: Hitoshi Takeshita, Shinsuke Fujisawa, Tomoyuki Hino, Akio Tajima
  • Patent number: 10938499
    Abstract: It is difficult in the elastic optical network to achieve a balance between the improvement in the frequency utilization efficiency and the increase in the probability of opening an optical path; therefore, an optical path controller according to an exemplary aspect of the present invention includes route selection means for searching for a route candidate being a candidate for a route to accommodate an optical path, and selecting a best possible route with a minimum route selection index serving as an index for route search; use rate collecting means for collecting a use rate serving as an index to indicate a usage condition of an optical frequency band in an optical fiber transmission line included in the route candidate; and route selection index judgment means for determining the route selection index based on the use rate.
    Type: Grant
    Filed: July 6, 2017
    Date of Patent: March 2, 2021
    Assignee: NEC Corporation
    Inventors: Shinsuke Fujisawa, Akio Tajima, Hitoshi Takeshita
  • Publication number: 20210058157
    Abstract: In a multi-layer network, a control load in the upper layer network increases, and the usage efficiency and the reliability of the entire network decrease; therefore, a multi-layer network system according to an exemplary aspect of the present invention includes a first network manager configured to set a logical path in a first network layer; and a second network manager configured to set a physical path corresponding to the logical path, in a second network layer, wherein the second network manager includes a network information storage configured to store physical network information including physical route information and transmission characteristic information on the second network layer, and the first network manager sets the logical path based on the physical network information.
    Type: Application
    Filed: November 6, 2020
    Publication date: February 25, 2021
    Applicant: NEC Corporation
    Inventors: Hitoshi TAKESHITA, Shinsuke FUJISAWA, Tomoyuki HINO, Akio TAJIMA
  • Publication number: 20210057869
    Abstract: In optical amplifiers that use a multicore optical fiber, the absorption efficiency of excitation light in an optical amplification medium is low and the amplification efficiency of light intensity becomes lower in the cladding excitation method; therefore, an optical amplification apparatus according to the present invention includes an optical amplification medium, having a gain in a wavelength band of signal light, configured to receive the signal light; excitation light introduction means for introducing, into the optical amplification medium, excitation light to excite the optical amplification medium; and residual excitation light introduction means for introducing, into the optical amplification medium, residual excitation light output from the optical amplification medium, the residual excitation light having a wavelength component of the excitation light.
    Type: Application
    Filed: April 8, 2019
    Publication date: February 25, 2021
    Applicant: NEC Corporation
    Inventors: Hitoshi TAKESHITA, Keiichi MATSUMOTO, Emmanuel LE TAILLANDIER DE GABORY
  • Publication number: 20210013965
    Abstract: A submarine optical communication system control device (1) according to the present invention includes: a light intensity distribution determination device (2) configured to determine an optimum distribution of signal light intensity of each optical path for each allocated frequency; a light intensity distribution measuring device (3) configured to measure a light intensity distribution of an optical path after transmission through a submarine cable transmission line; an equalization setting calculation unit (4) configured to calculate a gain equalization setting for compensating for the difference between an optimum distribution in the light intensity distribution determination device and a measured distribution in the light intensity distribution measuring device; and a variable gain equalizer (5) configured to compensate for a light intensity distribution of an optical path to the optimum distribution, based on a gain equalization setting in the equalization setting calculation unit.
    Type: Application
    Filed: March 27, 2018
    Publication date: January 14, 2021
    Applicant: NEC CORPORATION
    Inventors: Shinsuke FUJISAWA, Hitoshi TAKESHITA, Shigeyuki YANAGIMACHI, Emmanuel LE TAILLANDIER DE GABORY
  • Publication number: 20200374607
    Abstract: This optical path setting device comprises: a transmission characteristic calculating means for calculating an inter-endpoint transmission characteristic that is a characteristic for transmission between endpoints of an optical path accommodating traffic in a plurality of optical communication systems; a required wavelength bandwidth determining means for determining a required wavelength bandwidth that is a wavelength bandwidth meeting an arrival performance of the optical path on the basis of the inter-endpoint transmission characteristic; and an accommodating wavelength band determining means for determining, as an accommodating wavelength band for accommodating the optical path, a common wavelength band that is a wavelength band where an optical path having the required wavelength bandwidth can be allocated, and that is common to the plurality of optical communication systems.
    Type: Application
    Filed: November 29, 2018
    Publication date: November 26, 2020
    Applicant: NEC CORPORATION
    Inventors: Shinsuke FUJISAWA, Hitoshi TAKESHITA, Shigeyuki YANAGIMACHI, Emmanuel LE TAILLANDIER DE GABORY
  • Patent number: 10848245
    Abstract: In a multi-layer network, a control load in the upper layer network increases, and the usage efficiency and the reliability of the entire network decrease; therefore, a multi-layer network system according to an exemplary aspect of the present invention includes a first network manager configured to set a logical path in a first network layer; and a second network manager configured to set a physical path corresponding to the logical path, in a second network layer, wherein the second network manager includes a network information storage configured to store physical network information including physical route information and transmission characteristic information on the second network layer, and the first network manager sets the logical path based on the physical network information.
    Type: Grant
    Filed: December 15, 2015
    Date of Patent: November 24, 2020
    Assignee: NEC CORPORATION
    Inventors: Hitoshi Takeshita, Shinsuke Fujisawa, Tomoyuki Hino, Akio Tajima
  • Patent number: 10848262
    Abstract: In an optical communication network using the wavelength division multiplexing system, the accommodation efficiency for the optical paths decreases, and it becomes difficult to use the optical communication network efficiently, if the optical frequency slots are used concentrically in a specific optical fiber; therefore, an optical path design apparatus according to an exemplary aspect of the present invention includes route candidate selection means for searching for a route of an optical path to accommodate a communication demand and selecting a plurality of route candidates; optical path candidate selection means for selecting a plurality of optical path candidates by allocating an optical frequency band required to accommodate the optical path to each of optical fibers on the plurality of route candidates; and optical path determination means for determining the optical path from among the plurality of optical path candidates based on an optical frequency band utilization rate in the optical fibers.
    Type: Grant
    Filed: September 20, 2017
    Date of Patent: November 24, 2020
    Assignee: NEC CORPORATION
    Inventors: Hitoshi Takeshita, Shinsuke Fujisawa, Akio Tajima
  • Publication number: 20200344533
    Abstract: It is difficult to improve the usage efficiency of an optical communication network due to the passband narrowing effect in a wavelength selection process in an optical communication network using a wavelength division multiplexing system; therefore, an optical network management apparatus according to an exemplary aspect of the present invention includes wavelength selection information generating means for generating wavelength selection information on a wavelength selection process through which an optical path accommodating an information signal goes, with respect to each optical path; and wavelength selection information notifying means for notifying an optical node device through which the optical path goes of the wavelength selection information.
    Type: Application
    Filed: July 9, 2020
    Publication date: October 29, 2020
    Applicant: NEC CORPORATION
    Inventors: Hitoshi TAKESHITA, Shinsuke FUJISAWA, Tomoyuki HINO, Akio TAJIMA
  • Publication number: 20200313765
    Abstract: If wavelength defragmentation is performed during the operation of an optical network, an instantaneous interruption of a network arises; consequently, data are lost; therefore, an optical network control method according to an exemplary aspect of the present invention includes monitoring a data volume of a client signal to be transmitted using a plurality of optical subcarriers; and performing synchronously, depending on a variation in the data volume, an optical subcarrier changing process of changing an active optical subcarrier, of the plurality of optical subcarriers, to be used for transmitting the client signal, and a remapping process of remapping the client signal onto an active optical subcarrier after having been changed.
    Type: Application
    Filed: June 17, 2020
    Publication date: October 1, 2020
    Applicant: NEC Corporation
    Inventors: Tomoyuki HINO, Akio TAJIMA, Hitoshi TAKESHITA, Shinsuke FUJISAWA
  • Patent number: 10750259
    Abstract: It is difficult to improve the usage efficiency of an optical communication network due to the passband narrowing effect in a wavelength selection process in an optical communication network using a wavelength division multiplexing system; therefore, an optical network management apparatus according to an exemplary aspect of the present invention includes wavelength selection information generating means for generating wavelength selection information on a wavelength selection process through which an optical path accommodating an information signal goes, with respect to each optical path; and wavelength selection information notifying means for notifying an optical node device through which the optical path goes of the wavelength selection information.
    Type: Grant
    Filed: June 18, 2019
    Date of Patent: August 18, 2020
    Assignee: NEC CORPORATION
    Inventors: Hitoshi Takeshita, Shinsuke Fujisawa, Tomoyuki Hino, Akio Tajima
  • Patent number: 10715249
    Abstract: If wavelength defragmentation is performed during the operation of an optical network, an instantaneous interruption of a network arises; consequently, data are lost; therefore, an optical network control method according to an exemplary aspect of the present invention includes monitoring a data volume of a client signal to be transmitted using a plurality of optical subcarriers; and performing synchronously, depending on a variation in the data volume, an optical subcarrier changing process of changing an active optical subcarrier, of the plurality of optical subcarriers, to be used for transmitting the client signal, and a remapping process of remapping the client signal onto an active optical subcarrier after having been changed.
    Type: Grant
    Filed: March 18, 2016
    Date of Patent: July 14, 2020
    Assignee: NEC CORPORATION
    Inventors: Tomoyuki Hino, Akio Tajima, Hitoshi Takeshita, Shinsuke Fujisawa