Patents by Inventor Wataru Kawasaki

Wataru Kawasaki 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: 9755777
    Abstract: An optical transmitter includes a dummy optical source, a polarized wave beam coupler, and an auto gain control (AGC)-system amplifier. The dummy optical source outputs, out of an optical signal in which an optical path signal and an optical packet signal are mixed, a dummy signal having a wavelength identical to that of the optical packet signal. The polarized wave beam coupler multiplexes the dummy signal with the optical signal so that the dummy signal is orthogonal to the optical signal so as to output an output signal. The AGC-system amplifier inputs the output signal, and amplifies the output signal with a predetermined amplification factor corresponding to a power difference between input power and output power of an optical amplifier.
    Type: Grant
    Filed: June 24, 2015
    Date of Patent: September 5, 2017
    Assignee: FUJITSU LIMITED
    Inventors: Koji Bato, Tomoyuki Sakata, Tatsuro Kishida, Koji Matsunaga, Tatsuya Toyozumi, Yuichiro Sakane, Wataru Kawasaki
  • Patent number: 9720641
    Abstract: A music distribution server according to an embodiment provides a service in which users can easily enjoy digital contents. The server may include an information storage unit storing various tables and data bases, a playback transmission unit transmitting, in response to playback requests, music data to a terminal device in a streaming method, and a purchase transmission unit transmitting, in response to a purchase request, the music data to the terminal device in a downloading method, a ticket possession status update unit updating a possession status of virtual tickets used for playback of the music data possessed by users, a ticket providing unit providing the virtual tickets to users, a comment management unit managing users' comments on music pieces, a recommendation management unit managing recommendation of music pieces by one user to other users, and a ticket offer management unit offering the virtual tickets from one user to other users.
    Type: Grant
    Filed: September 13, 2013
    Date of Patent: August 1, 2017
    Inventors: Takayasu Satake, Wataru Kawasaki, Mamoru Yamashiki
  • Patent number: 9450698
    Abstract: The optical transmission device includes an N×N optical switch, an optical packet receiver and an optical packet generation unit. The N×N optical switch transmits data in which a plurality of optical signals each having a different wavelength is multiplexed. The optical packet receiver detects change in the number of wavelengths of optical signals constituting the data. The optical packet generation unit generates, when the change is detected by the optical packet receiver, data to be transmitted by the N×N optical switch, using optical signals for the number of wavelengths after the change.
    Type: Grant
    Filed: June 3, 2014
    Date of Patent: September 20, 2016
    Assignee: FUJITSU LIMITED
    Inventors: Koji Matsunaga, Tatsuya Toyozumi, Yasuo Tanaka, Yuichiro Sakane, Koji Bato, Wataru Kawasaki, Tatsuhiko Saito
  • Patent number: 9270382
    Abstract: An optical communication apparatus includes a variable resistor unit, a measurement unit, and a control unit. The variable resistor unit is arranged at a pre-stage of an electrical/optical conversion unit, which converts an electrical signal obtained by converting an input packet to an optical signal having a waveform corresponding to a potential difference between a positive phase component and a negative phase component of the electrical signal by using the potential difference. The variable resistor unit provides a resistor that varies a midpoint of potential of the positive phase component or the negative phase component. The measurement unit measures a ratio of a presence period, which is a period where the input packet is present, to a sum of the presence period and a non-presence period. The control unit controls a value of the resistor provided to the positive phase component or the negative phase component based on the ratio.
    Type: Grant
    Filed: June 3, 2014
    Date of Patent: February 23, 2016
    Assignee: FUJITSU LIMITED
    Inventors: Yuichiro Sakane, Koji Matsunaga, Yasuo Tanaka, Tatsuya Toyozumi, Koji Bato, Wataru Kawasaki, Tatsuhiko Saito
  • Publication number: 20160020866
    Abstract: An optical transmitter includes a dummy optical source, a polarized wave beam coupler, and an auto gain control (AGC)-system amplifier. The dummy optical source outputs, out of an optical signal in which an optical path signal and an optical packet signal are mixed, a dummy signal having a wavelength identical to that of the optical packet signal. The polarized wave beam coupler multiplexes the dummy signal with the optical signal so that the dummy signal is orthogonal to the optical signal so as to output an output signal. The AGC-system amplifier inputs the output signal, and amplifies the output signal with a predetermined amplification factor corresponding to a power difference between input power and output power of an optical amplifier.
    Type: Application
    Filed: June 24, 2015
    Publication date: January 21, 2016
    Applicants: FUJITSU LIMITED, FUJITSU TELECOM NETWORKS LIMITED
    Inventors: Koji BATO, TOMOYUKI SAKATA, Tatsuro Kishida, Koji Matsunaga, Tatsuya Toyozumi, Yuichiro Sakane, Wataru Kawasaki
  • Publication number: 20150363158
    Abstract: A music distribution server according to an embodiment provides a service in which users can easily enjoy digital contents. The server may include an information storage unit storing various tables and data bases, a playback transmission unit transmitting, in response to playback requests, music data to a terminal device in a streaming method, and a purchase transmission unit transmitting, in response to a purchase request, the music data to the terminal device in a downloading method, a ticket possession status update unit updating a possession status of virtual tickets used for playback of the music data possessed by users, a ticket providing unit providing the virtual tickets to users, a comment management unit managing users' comments on music pieces, a recommendation management unit managing recommendation of music pieces by one user to other users, and a ticket offer management unit offering the virtual tickets from one user to other users.
    Type: Application
    Filed: September 13, 2013
    Publication date: December 17, 2015
    Inventors: Takayasu SATAKE, Wataru KAWASAKI, Mamoru YAMASHIKI
  • Patent number: 9112637
    Abstract: An optical transmission device that receives a wavelength division multiplexed optical signal obtained by dividing an optical packet signal and performing wavelength multiplexing and that transmits via an optical switch the received wavelength division multiplexed optical signal includes an optical power level measurement unit configured to measure respective optical power levels of respective optical signals of wavelengths included in the wavelength division multiplexed optical signal, and a routing information determinator configured to determine routing information of the wavelength division multiplexed optical signal on the basis of the measured optical power levels.
    Type: Grant
    Filed: October 11, 2013
    Date of Patent: August 18, 2015
    Assignees: FUJITSU LIMITED, FUJITSU TELECOM NETWORKS LIMITED
    Inventors: Yuichiro Sakane, Koji Bato, Tatsuya Toyozumi, Koji Matsunaga, Wataru Kawasaki, Tatsuhiko Saito
  • Publication number: 20140355978
    Abstract: An optical transmission system includes a transmission side optical transmission apparatus having a transmitting unit configured to transmit optical signals of a predetermined number of differing wavelengths, and a processor configured to apply to the optical signals transmitted from the transmitting unit, a predetermined offset related to a tilt; and a reception side optical transmission apparatus having a receiving unit configured to receive the optical signals transmitted from the transmitting unit, a measuring unit configured to measure an optical signal count of the optical signals receivable by the receiving unit, and a notifying unit configured to give notification of the optical signal count measured by the measuring unit. The processor adjusts the offset in an increasing direction when the optical signal count notified by the notifying unit increases, and adjusts the offset in a decreasing direction when the optical signal count notified by the notifying unit decreases.
    Type: Application
    Filed: May 27, 2014
    Publication date: December 4, 2014
    Applicants: FUJITSU LIMITED, FUJITSU TELECOM NETWORKS LIMITED
    Inventors: TOMOYUKI SAKATA, Koji BATO, Tatsuro Kishida, Wataru Kawasaki, Tatsuhiko Saito
  • Publication number: 20140355980
    Abstract: An optical communication apparatus includes a variable resistor unit, a measurement unit, and a control unit. The variable resistor unit is arranged at a pre-stage of an electrical/optical conversion unit, which converts an electrical signal obtained by converting an input packet to an optical signal having a waveform corresponding to a potential difference between a positive phase component and a negative phase component of the electrical signal by using the potential difference. The variable resistor unit provides a resistor that varies a midpoint of potential of the positive phase component or the negative phase component. The measurement unit measures a ratio of a presence period, which is a period where the input packet is present, to a sum of the presence period and a non-presence period. The control unit controls a value of the resistor provided to the positive phase component or the negative phase component based on the ratio.
    Type: Application
    Filed: June 3, 2014
    Publication date: December 4, 2014
    Applicants: FUJITSU LIMITED, FUJITSU TELECOM NETWORKS LIMITED
    Inventors: Yuichiro Sakane, Koji Matsunaga, Yasuo Tanaka, Tatsuya Toyozumi, Koji Bato, Wataru Kawasaki, Tatsuhiko Saito
  • Publication number: 20140355976
    Abstract: The optical transmission device includes an N×N optical switch, an optical packet receiver and an optical packet generation unit. The N×N optical switch transmits data in which a plurality of optical signals each having a different wavelength is multiplexed. The optical packet receiver detects change in the number of wavelengths of optical signals constituting the data. The optical packet generation unit generates, when the change is detected by the optical packet receiver, data to be transmitted by the N×N optical switch, using optical signals for the number of wavelengths after the change.
    Type: Application
    Filed: June 3, 2014
    Publication date: December 4, 2014
    Applicants: FUJITSU LIMITED, FUJITSU TELECOM NETWORKS LIMITED
    Inventors: Koji Matsunaga, Tatsuya Toyozumi, Yasuo Tanaka, Yuichiro Sakane, Koji Bato, Wataru Kawasaki, Tatsuhiko Saito
  • Patent number: 8897638
    Abstract: An optical packet switching apparatus includes an optical packet switching apparatus, an optical transmitting apparatus, and an optical packet receiving apparatus. The optical packet transmitting apparatus includes a packet generator for generating a packet signal by adding the routing information to a received client signal, a BIP adding unit for adding BIP to the generated packet signal, and an electrical-to-optical converter for converting the packet signal, to which the BIP has been added, into an optical packet signal so as to be sent out. The optical packet receiving apparatus includes an electrical-to-optical converter for converting the received optical packet signal into an electrical packet signal, and a BIP comparison unit for detecting the error occurrence in the packet signal, based on the BIP added to the packet signal.
    Type: Grant
    Filed: April 24, 2012
    Date of Patent: November 25, 2014
    Assignee: Fujitsu Telecom Networks Limited
    Inventors: Koshi Kitajima, Satoshi Fukutomi, Wataru Kawasaki
  • Patent number: 8891966
    Abstract: An optical packet switching device causes branching of an optical packet that is input to an optical switch and detects a synchronization pattern having a predetermined number of bits from the branched optical packet. Then, the optical packet switching device calculates a synchronization point indicating a location of the synchronization pattern with respect to a detection timing and controls, in accordance with the calculated synchronization point, a delay amount of a delay element that delays an optical packet ON signal that is output to the optical switch.
    Type: Grant
    Filed: April 17, 2012
    Date of Patent: November 18, 2014
    Assignees: Fujitsu Limited, Fujitsu Telecom Networks Limited
    Inventors: Tatsuya Toyozumi, Koji Matsunaga, Yasuo Tanaka, Hironobu Fukuura, Wataru Kawasaki, Shota Mori
  • Patent number: 8755374
    Abstract: An optical packet switch device includes an optical switch control section and an optical switch section. The optical switch control section includes a synchronization pattern detecting unit which detects a frame synchronization pattern from a parallel data signal and detects a delay bit number showing that the frame synchronization pattern is stored at a position shifted by how many bits from the first bit of the parallel data signal, a header analysis unit which analyzes a header and detects an optical packet length and route information of an optical packet signal, and an output competition determining unit which determines passing/discarding of the optical packet signals competing with each other based on the optical packet length and the route information detected by the header analysis unit and delay bit number information detected by the synchronization pattern detecting unit.
    Type: Grant
    Filed: December 27, 2011
    Date of Patent: June 17, 2014
    Assignee: Fujitsu Telecom Networks Limited
    Inventors: Shota Mori, Wataru Kawasaki
  • Patent number: 8718470
    Abstract: An optical packet switching apparatus includes an optical coupler for branching off a received optical packet signal, an optical switch unit for switching the route of one of the branched-off optical packet signals so as to be outputted, and an optical switch control unit for controlling the optical switch unit. The optical switch control unit includes an optical-to-electrical conversion unit for converting the other of the branched-off optical packet signals into an electrical packet signal, a serial/parallel conversion unit capacitively coupled to the optical-to-electrical conversion unit, a packet density detector for detecting the packet density of the received packet signal, and a DC offset adjustment unit for adjusting the DC offset voltage of the packet signal, inputted to the serial/parallel conversion unit, according to the packet density information detected by the packet density detector.
    Type: Grant
    Filed: June 20, 2012
    Date of Patent: May 6, 2014
    Assignee: Fujitsu Telecom Networks Limited
    Inventor: Wataru Kawasaki
  • Publication number: 20140112661
    Abstract: An optical transmission device that receives a wavelength division multiplexed optical signal obtained by dividing an optical packet signal and performing wavelength multiplexing and that transmits via an optical switch the received wavelength division multiplexed optical signal includes an optical power level measurement unit configured to measure respective optical power levels of respective optical signals of wavelengths included in the wavelength division multiplexed optical signal, and a routing information determinator configured to determine routing information of the wavelength division multiplexed optical signal on the basis of the measured optical power levels.
    Type: Application
    Filed: October 11, 2013
    Publication date: April 24, 2014
    Applicants: FUJITSU TELECOM NETWORKS LIMITED, FUJITSU LIMITED
    Inventors: Yuichiro Sakane, Koji BATO, Tatsuya Toyozumi, KOJI MATSUNAGA, WATARU KAWASAKI, TATSUHIKO SAITO
  • Patent number: 8630541
    Abstract: Provided is a wavelength division multiplexing transmission apparatus that enables operation control of transponders each carrying an FBTL optical module from the monitoring control unit by the same operation control as one for the transponders each carrying an NB optical module with four wavelengths assigned. For that purpose, the wavelength division multiplexing transmission apparatus includes the transponders for converting optical signals from wideband wavelengths to narrowband wavelengths, and a monitoring control unit for controlling the transponders by instructions from an operator.
    Type: Grant
    Filed: December 18, 2008
    Date of Patent: January 14, 2014
    Assignee: Fujitsu Telecom Networks Limited
    Inventor: Wataru Kawasaki
  • Patent number: 8542996
    Abstract: An optical packet switching apparatus includes an optical coupler, an optical switch unit, and an optical switch control unit. The optical switch control unit includes an optical-to-electrical converter, a serial/parallel converter, an arrangement detector, a rearrangement unit, a frame synchronization unit, a route detector, a control signal generator, and an adjustment unit for adjusting the timing with which to output an optical switch control signal to the optical switch unit, based on arrangement information on a frame synchronization pattern fed from the arrangement detector.
    Type: Grant
    Filed: March 7, 2011
    Date of Patent: September 24, 2013
    Assignee: Fujitsu Telecom Networks Limited
    Inventors: Wataru Kawasaki, Shota Mori
  • Publication number: 20120328284
    Abstract: An optical packet switching apparatus includes an optical coupler for branching off a received optical packet signal, an optical switch unit for switching the route of one of the branched-off optical packet signals so as to be outputted, and an optical switch control unit for controlling the optical switch unit. The optical switch control unit includes an optical-to-electrical conversion unit for converting the other of the branched-off optical packet signals into an electrical packet signal, a serial/parallel conversion unit capacitively coupled to the optical-to-electrical conversion unit, a packet density detector for detecting the packet density of the received packet signal, and a DC offset adjustment unit for adjusting the DC offset voltage of the packet signal, inputted to the serial/parallel conversion unit, according to the packet density information detected by the packet density detector.
    Type: Application
    Filed: June 20, 2012
    Publication date: December 27, 2012
    Inventor: Wataru Kawasaki
  • Publication number: 20120315039
    Abstract: An optical packet switching device causes branching of an optical packet that is input to an optical switch and detects a synchronization pattern having a predetermined number of bits from the branched optical packet. Then, the optical packet switching device calculates a synchronization point indicating a location of the synchronization pattern with respect to a detection timing and controls, in accordance with the calculated synchronization point, a delay amount of a delay element that delays an optical packet ON signal that is output to the optical switch.
    Type: Application
    Filed: April 17, 2012
    Publication date: December 13, 2012
    Applicants: FUJITSU TELECOM NETWORKS LIMITED, FUJITSU LIMITED
    Inventors: Tatsuya TOYOZUMI, Koji MATSUNAGA, Yasuo TANAKA, Hironobu FUKUURA, Wataru KAWASAKI, Shota MORI
  • Publication number: 20120275783
    Abstract: An optical packet switching apparatus includes an optical packet switching apparatus, an optical transmitting apparatus, and an optical packet receiving apparatus. The optical packet transmitting apparatus includes a packet generator for generating a packet signal by adding the routing information to a received client signal, a BIP adding unit for adding BIP to the generated packet signal, and an electrical-to-optical converter for converting the packet signal, to which the BIP has been added, into an optical packet signal so as to be sent out. The optical packet receiving apparatus includes an electrical-to-optical converter for converting the received optical packet signal into an electrical packet signal, and a BIP comparison unit for detecting the error occurrence in the packet signal, based on the BIP added to the packet signal.
    Type: Application
    Filed: April 24, 2012
    Publication date: November 1, 2012
    Inventors: Koshi KITAJIMA, Satoshi FUKUTOMI, Wataru KAWASAKI