Patents by Inventor Takao Naito

Takao Naito 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: 20110044698
    Abstract: A demodulator comprises an input splitter, optical device sets, and couplers. The input splitter splits an input signal comprising symbols to yield a number of signals. A first optical device set directs a signal of along a first path. A second optical device set directs another signal along a second path to yield a delayed signal. At least a portion of the second path is in free space. A path length difference between the first path and the second path introduces a delay between the first signal and the second signal. A coupler receives a portion of the signal and a portion of the delayed signal to generate interference, where the interference indicates a phase shift between a phase corresponding to a symbol and a successive phase corresponding to a successive symbol.
    Type: Application
    Filed: December 31, 2009
    Publication date: February 24, 2011
    Applicant: Fujitsu Limited
    Inventors: Cechan Tian, Takao Naito
  • Publication number: 20110043897
    Abstract: A system for optical communication including an optical amplifier card configured to receive a plurality of pump laser modules. The optical amplifier card includes a receptacle configured to receive the pump laser module, a connector configured to couple the pump laser module to the optical amplifier card, a monitor configured to measure at least the optical output power of the pump laser module, and a pump combiner communicatively coupled to the monitor. The pump combiner is configured to receive a signal from the monitor indicating a drop in the output power of a first pump laser module below a threshold level, and, in response to the signal, switch the optical amplifier card from using the optical power of the first pump laser module to using the optical power of a second pump laser module without substantially affecting normal operation of the optical amplifier card.
    Type: Application
    Filed: August 18, 2009
    Publication date: February 24, 2011
    Inventors: Youichi Akasaka, Takao Naito
  • Publication number: 20110044689
    Abstract: A system for cross-phase-modulation-noise reduced transmission in hybrid networks includes a first, second, and third set of optical transmitters. The first set of optical transmitters transmits a set of ten gigabit per second signals. The second set of optical transmitters transmits a set of forty gigabit per second signals. The third set of optical transmitters transmits a set of one hundred gigabit per second signals. On a wavelength spectrum, the set of 10 G signals is immediately adjacent to the set of 100 G signals, and the set of 100 G signals is immediately adjacent to the set of 40 G signals. The set of 10 G signals and the set of 100 G signals are not separated by a guard band. In addition, the set of 100 G signals and the set of 40 G signals are also not separated by a guard band.
    Type: Application
    Filed: August 21, 2009
    Publication date: February 24, 2011
    Inventors: Olga I. Vassilieva, Takao Naito
  • Publication number: 20100329120
    Abstract: According to particular embodiments, determining disjoint paths includes receiving a graph representing a network comprising nodes and links. The graph is transformed such that the number of intermediate nodes of a path indicates the number of regenerators for the path. A set of seed paths from a source node to a destination node of the transformed graph is generated. For each seed path, a shortest path from the source node to the destination node is determined to yield one or more pairs of disjoint paths from the source node to the destination node. An optimized pair of disjoint paths is selected, where the optimized pair of disjoint paths has an optimized number of regenerators.
    Type: Application
    Filed: June 30, 2009
    Publication date: December 30, 2010
    Applicant: Fujitsu Limited
    Inventors: Qiong Zhang, Xi Wang, Paparao Palacharla, Takao Naito
  • Patent number: 7860402
    Abstract: A system operable to modulate a signal according to phase-shift keying (PSK) modulation includes a translator and a phase modulation system. The translator receives data signals and translates the data signals into control signals, where the number of control signals is greater than the number of data signals. The phase modulation system includes phase modulators. Each phase modulator receives a control signal and PSK modulates a communication signal according to the control signal.
    Type: Grant
    Filed: January 26, 2007
    Date of Patent: December 28, 2010
    Assignee: Fujitsu Limited
    Inventors: Cechan Tian, Takao Naito
  • Patent number: 7853147
    Abstract: The present invention provides an information processing system, comprising a plurality of calculation nodes with an optical transmitter, which individually outputs a plurality of optical signals each having a different wavelength, and an optical receiver, which individually receives a plurality of optical signals each having a different wavelength, an optical transmission path connecting a plurality of the calculation nodes to each other, and optical pathway switching unit, lying in the optical transmission path, for transmitting the optical signal to the specific calculation node in accordance with a wavelength of the optical signal output from one of the calculation nodes.
    Type: Grant
    Filed: June 7, 2005
    Date of Patent: December 14, 2010
    Assignee: Fujitsu Limited
    Inventors: Toshiki Tanaka, Yasuhiko Aoki, Hideyuki Miyata, Takao Naito, Kouichiro Amemiya
  • Publication number: 20100266281
    Abstract: According to one embodiment, allocating demand includes receiving a demand graph that describes demands of a network. One or more weights are calculated for each demand. The demands are allocated according to the weights of the demands to optimize optical line card sharing.
    Type: Application
    Filed: June 22, 2009
    Publication date: October 21, 2010
    Applicant: Fujitsu Limited
    Inventors: Xi Wang, Paparao Palacharla, Takao Naito
  • Patent number: 7813640
    Abstract: An optical connection switching according to the present invention comprises an optical connection switching facility capable of making a connection between any one of optical input ports and any one of optical output ports, one or more optical transmitting/receiving units connected to a portion of the optical input/output ports, and management control units for controlling the optical connection switching facility to make a connection between the optical input/output port connected to the optical transmitting/receiving unit and the optical input/output port connected to equipment for acquiring and managing information on the equipment by making a communication with the equipment through the use of the optical transmitting/receiving unit. This enables acquiring the information on the equipment having an optical communication interface to be optically connected, thereby automating the connection management of the equipment.
    Type: Grant
    Filed: March 16, 2005
    Date of Patent: October 12, 2010
    Assignee: Fujitsu Limited
    Inventors: Kouichirou Amemiya, Takao Naito, Toru Katagiri, Toshiki Tanaka
  • Patent number: 7801393
    Abstract: Monitoring a bias point of an optical modulator includes receiving an optical signal modulated by the optical modulator. Photons of the optical signal are received at a photon reactive material operable to produce a reaction in response to the arrival of a predetermined number of photons. Reactions are produced in response to the arrival of the photons of the optical signal. Feedback is generated in response to the reactions. The feedback reflects the waveform of the optical signal, and indicates one or more bias points of the optical modulator.
    Type: Grant
    Filed: April 20, 2009
    Date of Patent: September 21, 2010
    Assignee: Fujitsu Limited
    Inventors: Cechan Tian, Takao Naito
  • Publication number: 20100226833
    Abstract: A polyisocyanate production method that can allow effective use of hydrogen chloride produced secondarily in a polyisocyanate production process, while allowing reduction of environmental burdens, and a polyisocyanate production system for performing the polyisocyanate production method. After chlorine is allowed to react with carbon monoxide to produce carbonyl chloride in a carbonyl chloride producing reactor, the carbonyl chloride produced in the carbonyl chloride producing reactor is allowed to react with polyamine in an isocyanate producing reactor to produce polyisocyanate. Then, after hydrochloric gas produced secondarily in the isocyanate producing reactor is purified in a hydrogen chloride purifying column, the purified hydrochloric gas is oxidized in a hydrogen chloride oxidizing reactor to produce chlorine.
    Type: Application
    Filed: April 16, 2010
    Publication date: September 9, 2010
    Applicant: Mitsui Chemicals Polyurethanes, Inc.
    Inventors: Masaaki Sasaki, Takao Naito, Fumiaki Hirata, Masato Saruwatari, Hirofumi Takahashi, Kouji Maeba, Tsugio Imaizumi, Takuya Saeki, Takashi Yamaguchi, Kouichirou Terada
  • Publication number: 20100228958
    Abstract: An information processing apparatus includes a first circuit configuration section, a second circuit configuration section and a circuit configuration controller. The first circuit configuration section includes a first circuit configuration configured by a plurality of first calculation units. Each of the first calculation units has a circuit being configured to be dynamically reconfigured. The second circuit configuration section includes a second circuit configuration configured by a plurality of second calculation units. Each of the second calculation units has a fixed circuit. The circuit configuration controller controls the first circuit configuration and the second circuit configuration in accordance with processing time to be taken for performing information processing.
    Type: Application
    Filed: August 7, 2009
    Publication date: September 9, 2010
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Takao NAITO, Kazuo YAMADA
  • Publication number: 20100150569
    Abstract: A method for upgrading an optoelectrical system includes securing a transmitter to a line card, wherein the line card comprises an optoelectrical connector. It also includes coupling the transmitter to the connector, wherein the connector comprises an embedded fiber configured to be coupled to the transmitter. In addition, the method includes inserting a pluggable form factor module comprising a receiver, an input port, and an output port into a cage secured to the line card. Further, the method includes coupling the pluggable form factor module to the connector such that an optical signal transmitted by the transmitter propagates in an optical line of sight between the embedded fiber of the connector and the output port. The connector comprises electrical contacts that are configured to be coupled to the module such that the receiver can convert optical signals received at the input port into electrical signals and transmit the electrical signals to the line card via the connector.
    Type: Application
    Filed: December 12, 2008
    Publication date: June 17, 2010
    Applicant: Fujitsu Limited
    Inventors: Alexander Umnov, Dung Q. Tran, Takao Naito
  • Publication number: 20100150570
    Abstract: A system for optoelectrical communication includes a transmitter configured to transmit optical signals. It also includes a pluggable form factor module. The module includes an input port, an output port, and a receiver configured to convert optical signals received at the input port into electrical signals. The system further includes an optoelectrical connector coupled to the module and the transmitter. The connector includes an embedded fiber coupled to the transmitter and configured to transmit the optical signals from the transmitter to the output port of the module. The connector also includes electrical contacts configured to receive the electrical signals from the receiver. The system includes a cage in a pluggable form factor configured to house the module and the connector, wherein the transmitter is positioned outside the cage.
    Type: Application
    Filed: December 12, 2008
    Publication date: June 17, 2010
    Applicant: Fujitsu Limited
    Inventors: Alexander Umnov, Dung Q. Tran, Takao Naito
  • Publication number: 20100142028
    Abstract: In accordance with a particular embodiment of the present invention, a device for modulating an optical beam is provided. The device may include a substrate comprising a non-ferromagnetic material and a thin film comprising a ferromagnetic semiconductor material disposed on the substrate. The thin film may be disposed on the substrate such that at least part of an optical beam incident on the thin film at an angle reflects off of a surface of the thin film. The thin film may be responsive to a magnetic field applied to the thin film such that varying the magnetic field varies the polarization of the light beam reflected off of the surface of the thin film.
    Type: Application
    Filed: December 7, 2009
    Publication date: June 10, 2010
    Applicant: Fujitsu Limited
    Inventors: Alexander Umnov, Takao Naito
  • Patent number: 7718145
    Abstract: A polyisocyanate production system is provided that can stably produce chlorine from hydrogen chloride produced secondarily while reacting stably between carbonyl chloride and polyamine and can perform an effective treatment of the hydrochloric gas produced secondarily. A hydrochloric gas control unit 32 controls a flow-rate control valve 23 to keep constant an amount of hydrogen chloride supplied from a hydrogen chloride purifying tank 4 to a hydrogen chloride oxidation reactor 6 via a second hydrochloric-gas connection line 11 to be constant, and also controls a pressure control valve 22 based on an inner pressure of the hydrogen chloride purifying tank 4 input from a pressure sensor 25 to discharge the hydrochloric gas from the hydrogen chloride purifying tank 4 to the hydrogen chloride absorbing column 5 via a first hydrochloric-gas connection line 10, so as to keep an inner pressure of the hydrogen chloride purifying tank 4 to be constant.
    Type: Grant
    Filed: March 17, 2006
    Date of Patent: May 18, 2010
    Assignee: Mitsui Chemicals, Inc.
    Inventors: Masaaki Sasaki, Hirofumi Takahashi, Kouji Maeba, Takao Naito, Kouichirou Terada, Takashi Yamaguchi, Takuya Saeki
  • Patent number: 7715719
    Abstract: In accordance with the teachings of the present invention, a system and method for transmitting traffic in a plurality of passive optical networks (PONs) is provided. In a particular embodiment, a method for transmitting traffic in a plurality of passive optical networks (PONs) includes transmitting traffic at a first wavelength and at a second wavelength from an optical line terminal (OLT). The method also includes combining the traffic in the first wavelength and the traffic in the second wavelength and splitting the combined traffic into a plurality of copies. The method further includes forwarding a first copy to a first wavelength router at a first distribution node and forwarding a second copy to a second wavelength router at a second distribution node, wherein the first wavelength router is coupled to a first set of optical network units (ONUs) and the second wavelength router is coupled to a second set of ONUs.
    Type: Grant
    Filed: January 26, 2007
    Date of Patent: May 11, 2010
    Assignee: Fujitsu Limited
    Inventors: Martin Bouda, Takao Naito
  • Patent number: 7715709
    Abstract: The optical switch, having a plurality of ports capable of switching optical signal routes in a network in the form of light, includes a detection means for detecting information in regard to the transmission condition of an optical signal passing through each port; and a control means for exchanging the transmission condition information between each switch and controlling the ports, so as to select one route from among a plurality of routes transmitting the optical signal based on the difference of transmission condition information between the relevant switches. The transmission condition information is the power of the optical signal. When the difference between each switch exists, or when at least one switch intervenes in the middle of the transmission route, by selecting a transmission route which minimizes accumulated differences among the switches, configuring a tree structure conventionally performed through manual operation can be set automatically in an optical network system.
    Type: Grant
    Filed: August 10, 2004
    Date of Patent: May 11, 2010
    Assignee: Fujitsu Limited
    Inventors: Kouichirou Amemiya, Takao Naito, Toshiki Tanaka
  • Patent number: 7693425
    Abstract: A system and method for dispersion compensation of an optical signal in a hybrid network includes generating optical traffic in a first set of one or more channels, wherein the traffic in the first set of channels is modulated using a first modulation technique. Optical traffic is generated in a second set of one or more channels, wherein the traffic in the second set of channels is modulated using a second modulation technique. An optical dispersion pre-compensation is applied to the second set of channels. The first set of channels and the second set of channels are combined to form an optical signal, and the optical signal is transmitted over an optical network.
    Type: Grant
    Filed: January 11, 2007
    Date of Patent: April 6, 2010
    Assignee: Fujitsu Limited
    Inventors: Olga I. Vassilieva, Takao Naito
  • Patent number: 7684706
    Abstract: In accordance with the teachings of the present invention, a system and method for traffic distribution in an optical network is provided. In a particular embodiment, a traffic distribution module in a passive optical network (PON), includes a filter configured to receive downstream traffic in a first set of one or more wavelengths and a second set of one or more wavelengths from an optical line terminal (OLT), direct the traffic in the first set of wavelengths to a primary power splitter, and direct the traffic in the second set of wavelengths to a first connector. The traffic distribution module also includes a primary power splitter and a plurality of secondary power splitters. The primary power splitter is configured to receive the traffic in the first set of wavelengths and distribute the traffic in the first set to the plurality of secondary power splitters coupled to the primary power splitter such that optical network units (ONUs) in the PON receive the traffic in the first set of wavelengths.
    Type: Grant
    Filed: June 27, 2006
    Date of Patent: March 23, 2010
    Assignee: Fujitsu Limited
    Inventors: Yoichi Akasaka, Martin Bouda, Takao Naito
  • Patent number: 7668466
    Abstract: A demodulator comprises an input splitter, optical device sets, and couplers. The input splitter splits an input signal comprising symbols to yield a number of signals. A first optical device set directs a signal of along a first path. A second optical device set directs another signal along a second path to yield a delayed signal. At least a portion of the second path is in free space. A path length difference between the first path and the second path introduces a symbol delay between the first signal and the second signal. A coupler receives a portion of the signal and a portion of the delayed signal to generate interference, where the interference indicates a phase shift between a phase corresponding to a symbol and a successive phase corresponding to a successive symbol.
    Type: Grant
    Filed: June 30, 2006
    Date of Patent: February 23, 2010
    Assignee: Fujitsui Limited
    Inventors: Cechan Tian, Takao Naito