Patents by Inventor Shinsuke Fujisawa

Shinsuke Fujisawa 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: 20170353244
    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: December 15, 2015
    Publication date: December 7, 2017
    Applicant: NEC Corporation
    Inventors: Hitoshi TAKESHITA, Shinsuke FUJISAWA, Tomoyuki HINO, Akio TAJIMA
  • Publication number: 20170338890
    Abstract: In an optical network system based on a wavelength division multiplexing system using a flexible frequency grid, with the diversification of optical modulation methods, the management burden on an optical network management device increases, and its control becomes complicated; therefore, an optical network system according to an exemplary aspect of the present invention includes an optical network management device configured to receive a traffic demand, design an optical path capable of accommodating the traffic demand, and create optical path design information of a design result; and an optical node device configured to be used for creating the optical path, wherein the optical node device calculates an allocable bandwidth from the optical path design information and optical node device information on a configuration of the optical node device, and the allocable bandwidth is an optical frequency bandwidth of a generable optical path that the optical node device is capable of generating, and the optical ne
    Type: Application
    Filed: November 11, 2015
    Publication date: November 23, 2017
    Applicant: NEC Corporation
    Inventors: Hitoshi TAKESHITA, Tomoyuki HINO, Shinsuke FUJISAWA, Akio TAJIMA
  • Patent number: 9819525
    Abstract: To provide signal generating apparatus that is capable of controlling the DC bias of the optical modulator applicable to various kinds of modulation format, a signal processing apparatus includes a digital processing unit for deserializing an input digital data into parallel data lanes, for comparing the value of the digital data of symbol rate F to at least one predetermined threshold value, for selecting an offset value based on the result of the comparison; and for adding the selected offset value to the digital data, a converting unit for converting the digital data added the offset value to analog signals in each lane; an optical modulating unit for modulating a lightwave according to the analog signals with predetermined modulation format at the symbol rate F, where the modulated signal contains a frequency component at F/N.
    Type: Grant
    Filed: July 31, 2013
    Date of Patent: November 14, 2017
    Assignee: NEC CORPORATION
    Inventors: Emmanuel Le Taillandier De Gabory, Daisaku Ogasahara, Shinsuke Fujisawa
  • Publication number: 20170302370
    Abstract: It is difficult in an optical network to achieve fault recovery in case of multiple failures without decreasing the usage efficiency of the optical network; therefore, an optical communication system according to an exemplary aspect of the present invention includes an optical network management device including an optical path setting means for setting, to a physical route differing from each other, a backup path corresponding to each of a plurality of active paths on an identical physical route, and a failure-case optical path setting means for setting a failure-case backup path with a compressed band of the backup path, to a physical route without a failure in a case where failures arising on more than one physical route among the physical routes; and an optical node device including an optical transceiver means for transmitting and receiving optical signals using failure-case backup path information resulting from setting by the failure-case optical path setting means.
    Type: Application
    Filed: September 15, 2015
    Publication date: October 19, 2017
    Applicant: NEC Corporation
    Inventors: Shinsuke FUJISAWA, Hitoshi TAKESHITA, Tomoyuki HINO, Akio TAJIMA
  • Publication number: 20170180073
    Abstract: In an optical network based on a dense wavelength division multiplexing system using a flexible frequency grid, it is difficult to improve the usage efficiency of an optical frequency band owing to the occurrence of fragmentation of the optical frequency band; therefore, an optical network controller according to an exemplary aspect of the present invention includes an optical frequency region setting means for dividing an optical frequency band used in an optical network based on a dense wavelength division multiplexing system using a flexible frequency grid, and setting a plurality of optical frequency regions; and an optical path setting means for setting optical paths having a common attribute in at least one of the plurality of optical frequency regions.
    Type: Application
    Filed: April 15, 2015
    Publication date: June 22, 2017
    Applicant: NEC Corporation
    Inventors: Hitoshi TAKESHITA, Shinsuke FUJISAWA, Tomoyuki HINO, Akio TAJIMA
  • Publication number: 20170163371
    Abstract: It is difficult to build a highly efficient multicarrier optical transmission system because a multicarrier optical transmitter and receiver has limits on the degree of freedom when allocating optical transmission frames to optical subcarriers; therefore, a multicarrier optical transmitter according to an exemplary aspect of the present invention includes transmission-signal generating unit for accommodating a client signal in an optical transmission frame, dividing the optical transmission frame, and outputting divided frames to a plurality of lanes; optical transmission frame multiplex processing unit including a plurality of multiplexing units each of which time-division multiplexing the optical transmission frame inputted from a predetermined input lane included in the plurality of lanes and outputting a single multiplexed optical transmission frame; and optical transmission unit for modulating a plurality of optical subcarriers using a plurality of the multiplexed optical transmission frames respectively
    Type: Application
    Filed: June 19, 2015
    Publication date: June 8, 2017
    Applicant: NEC Corporation
    Inventors: Tomoyuki HINO, Akio TAJIMA, Hitoshi TAKESHITA, Shinsuke FUJISAWA
  • Publication number: 20170078044
    Abstract: It is made possible to accommodate a plurality of services and transmit each of the accommodated services to a corresponding transmission device. An optical transmitter according to an exemplary aspect of the present invention includes sub-carrier adjusting means for outputting sub-carriers to a plurality of output ports according to a control signal; encoding processing means for mapping client data on a plurality of output lanes according to the control signal; a plurality of modulation means for modulating the sub-carriers inputted through the output ports by client data inputted through the output lanes and outputting modulated signals; and control means for generating and outputting the control signal based on transmission information.
    Type: Application
    Filed: March 11, 2015
    Publication date: March 16, 2017
    Applicant: NEC Corporation
    Inventors: Tomoyuki HINO, Shinsuke FUJISAWA, Hitoshi TAKESHITA, Akio TAJIMA
  • Publication number: 20170054506
    Abstract: In an optical network based on a dense wavelength division multiplexing system using a flexible frequency grid, it is difficult to improve the usage efficiency of an optical frequency band owing to the occurrence of fragmentation of the optical frequency band; therefore, an optical network controller according to an exemplary aspect of the present invention includes an optical frequency region setting means for setting a plurality of optical frequency regions in an optical frequency band used in an optical network based on a dense wavelength division multiplexing system using a flexible frequency grid; an optical path setting means for setting optical paths having a common attribute in at least one of the plurality of optical frequency regions; and an optical frequency region control means for changing an optical frequency width of the optical frequency region, and instructing the optical frequency region setting means to reconfigure, as the plurality of optical frequency regions, a plurality of optical frequ
    Type: Application
    Filed: April 15, 2015
    Publication date: February 23, 2017
    Applicant: NEC Corporation
    Inventors: Hitoshi TAKESHITA, Shinsuke FUJISAWA, Tomoyuki HINO, Akio TAJIMA
  • Publication number: 20160352452
    Abstract: It is difficult to improve the wavelength-band utilization rate of an optical network as a whole while operating the optical network stably; and therefore, an optical network controller according to an exemplary aspect of the present invention includes optical wavelength region setting means for setting a wavelength region in an optical transmission line between a plurality of optical nodes composing an optical network using wavelength division multiplexing system dividing the wavelength region into consecutive regions of a first wavelength region and a second wavelength region; optical path setting means for setting a first optical path in the first wavelength region and a second optical path in the second wavelength region, the second optical path differing from the first optical path in a route; and control unit for instructing the plurality of optical nodes on a central wavelength and a usable band of signal light for the optical node to transmit based on a setting by the optical path setting means.
    Type: Application
    Filed: February 16, 2015
    Publication date: December 1, 2016
    Applicant: NEC Corporation
    Inventors: Hitoshi TAKESHITA, Shinsuke FUJISAWA, Ryuichi IKEMATSU, Akio TAJIMA, Tomoyuki HINO
  • Patent number: 9485033
    Abstract: Signal processing means includes carrier compensation means for compensating for a phase difference and a frequency difference between signal light and local light in relation to two polarization signals, so as to generate two carrier compensated signals, symbol determination means for demodulating the two carrier compensated signals on the basis of a signal arrangement of multi-value modulation, symbol rough-determination means for demodulating the two carrier compensated signals on the basis of a signal arrangement in which the number of multi-values of the multi-value modulation is reduced, selection means for selecting either of an output of the symbol determination means and an output of the symbol rough-determination means, and coefficient setting means for updating filter coefficients of polarized wave separation means by using an output selected by the selection means.
    Type: Grant
    Filed: October 5, 2012
    Date of Patent: November 1, 2016
    Assignee: NEC CORPORATION
    Inventors: Wakako Yasuda, Daisaku Ogasahara, Shinsuke Fujisawa
  • Patent number: 9473249
    Abstract: An optical signal generation unit (110) generates an optical signal for transmission by adding modulation based on a driving signal to a carrier wave. A filtering unit (120) performs a filtering process on the driving signal. The filtering unit (120) may perform time domain equalization, and may perform frequency domain equalization. Specifically, the filtering unit (120) performs a filtering process on the driving signal, and thus sets a peak value of a power spectral density of the optical signal for transmission to be equal to or less than a second reference value while an integrated value obtained by integrating the power spectral density of the optical signal for transmission in a frequency direction is maintained at equal to or greater than a first reference value.
    Type: Grant
    Filed: January 30, 2013
    Date of Patent: October 18, 2016
    Assignee: NEC CORPORATION
    Inventors: Shinsuke Fujisawa, Daisaku Ogasahara, Toru Takamichi
  • Publication number: 20160173304
    Abstract: To provide signal generating apparatus that is capable of controlling the DC bias of the optical modulator applicable to various kinds of modulation format, a signal processing apparatus includes a digital processing unit for deserializing an input digital data into parallel data lanes, for comparing the value of the digital data of symbol rate F to at least one predetermined threshold value, for selecting an offset value based on the result of the comparison; and for adding the selected offset value to the digital data, a converting unit for converting the digital data added the offset value to analog signals in each lane; an optical modulating unit for modulating a lightwave according to the analog signals with predetermined modulation format at the symbol rate F, where the modulated signal contains a frequency component at F/N.
    Type: Application
    Filed: July 31, 2013
    Publication date: June 16, 2016
    Inventors: Emmanuel LE TAILLANDIER DE GABORY, Daisaku OGASAHARA, Shinsuke FUJISAWA
  • Patent number: 9280032
    Abstract: An optical frequency conversion method and device are provided by which a component other than a desired harmonic component can be eliminated with high precision and an output lightwave with the desired frequency component can be easily extracted even if the frequency of a modulation signal is changed.
    Type: Grant
    Filed: April 23, 2012
    Date of Patent: March 8, 2016
    Assignee: NEC CORPORATION
    Inventor: Shinsuke Fujisawa
  • Publication number: 20150043925
    Abstract: An optical signal generation unit (110) generates an optical signal for transmission by adding modulation based on a driving signal to a carrier wave. A filtering unit (120) performs a filtering process on the driving signal. The filtering unit (120) may perform time domain equalization, and may perform frequency domain equalization. Specifically, the filtering unit (120) performs a filtering process on the driving signal, and thus sets a peak value of a power spectral density of the optical signal for transmission to be equal to or less than a second reference value while an integrated value obtained by integrating the power spectral density of the optical signal for transmission in a frequency direction is maintained at equal to or greater than a first reference value.
    Type: Application
    Filed: January 30, 2013
    Publication date: February 12, 2015
    Inventors: Shinsuke Fujisawa, Daisaku Ogasahara, Toru Takamichi
  • Publication number: 20140286638
    Abstract: Signal processing means includes carrier compensation means for compensating for a phase difference and a frequency difference between signal light and local light in relation to two polarization signals, so as to generate two carrier compensated signals, symbol determination means for demodulating the two carrier compensated signals on the basis of a signal arrangement of multi-value modulation, symbol rough-determination means for demodulating the two carrier compensated signals on the basis of a signal arrangement in which the number of multi-values of the multi-value modulation is reduced, selection means for selecting either of an output of the symbol determination means and an output of the symbol rough-determination means, and coefficient setting means for updating filter coefficients of polarized wave separation means by using an output selected by the selection means.
    Type: Application
    Filed: October 5, 2012
    Publication date: September 25, 2014
    Inventors: Wakako Yasuda, Daisaku Ogasahara, Shinsuke Fujisawa
  • Publication number: 20140043673
    Abstract: An optical frequency conversion method and device are provided by which a component other than a desired harmonic component can be eliminated with high precision and an output lightwave with the desired frequency component can be easily extracted even if the frequency of a modulation signal is changed.
    Type: Application
    Filed: April 23, 2012
    Publication date: February 13, 2014
    Applicant: NEC CORPORATION
    Inventor: Shinsuke Fujisawa
  • Patent number: 7479252
    Abstract: A method for manufacturing a throwaway tip is presented in which a green compact Q obtained by press-forming raw material powder for the throwaway tip is placed and sintered on a sintering plate 8. The green compact Q is press-formed so that the density of the raw material powder is gradually decreased toward a predetermined direction R, and the direction R is oriented substantially toward the outer circumference of the sintering plate 8 in plan view. Thus, it is possible to obtain a throwaway tip having sintering accuracy.
    Type: Grant
    Filed: March 26, 2004
    Date of Patent: January 20, 2009
    Assignee: Mitsubishi Materials Corporation
    Inventors: Yoshikazu Okada, Toru Narita, Shinsuke Fujisawa
  • Publication number: 20040202566
    Abstract: A method for manufacturing a throwaway tip is presented in which a green compact Q obtained by press-forming raw material powder for the throwaway tip is placed and sintered on a sintering plate 8. The green compact Q is press-formed so that the density of the raw material powder is gradually decreased toward a predetermined direction R, and the direction R is oriented substantially toward the outer circumference of the sintering plate 8 in plan view. Thus, it is possible to obtain a throwaway tip having sintering accuracy.
    Type: Application
    Filed: March 26, 2004
    Publication date: October 14, 2004
    Applicant: Mitsubishi Materials Corporation
    Inventors: Yoshikazu Okada, Toru Narita, Shinsuke Fujisawa