Patents Assigned to Nippon Telegraph & Telephone Corporation
  • Polarization maintaining optical fiber with improved polarization maintaining property
    Patent number: 6788865
    Abstract: A polarization maintaining optical fiber is formed by using a core in a cross sectional shape having different diameters along two orthogonal axes defined on a plane perpendicular to an optical axis, or a photonic crystal structure cladding having a diffraction grating with lattice intervals for realizing confinement of lights within the core which are different along two orthogonal axes defined on a plane perpendicular to an optical axis, or the photonic crystal structure cladding that is divided into four divided portions along a circumferential direction, where at least a part of lattice holes in a first pair of divided portions that are facing each other along one direction have a diameter larger than that of lattice holes in a second pair of divided portions that are facing each other along another direction orthogonal to the one direction.
    Type: Grant
    Filed: March 5, 2001
    Date of Patent: September 7, 2004
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Satoki Kawanishi, Katsunari Okamoto
  • Adiabatic charging register circuit
    Patent number: 6788121
    Abstract: An adiabatic charging register circuit including a plurality of n-channel MOSFET's and plurality of p-channel MOSFET's, is operated by a clock signal which has a gradually rising and an gradually falling waveform generated by using a charge recycle power source in which charge supplied to a load is at lease partially collected to said charge recycle power source, and following inequality is satisfied; |VTN|+|VTP|≧VDD wherein VTN is threshold of an n-channel MOSFET, VTP is threshold of a p-channel MOSFET, and VDD is output voltage of said charge recycle power source.
    Type: Grant
    Filed: June 4, 2001
    Date of Patent: September 7, 2004
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Shunji Nakata, Yuuichi Kado
  • Predictive encoding and decoding methods of video data
    Patent number: 6785331
    Abstract: Video data predictive encoding methods using the two kinds of prediction modes, the global and local motion compensation modes, are provided, by which unnecessary MCSEL is reduced as much as possible, and the data compression efficiency is improved. In the encoder, after a code word MCBPC indicating the macroblock type and presence/absence of the DCT coefficient of each of two blocks for sending color-difference signals, a code word MCSEL indicating which motion-compensating mode, global or local, was adopted for the prediction of the current macroblock is output if the macroblock was not intraframe-encoded.
    Type: Grant
    Filed: July 28, 1999
    Date of Patent: August 31, 2004
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Hirohisa Jozawa, Atsushi Shimizu, Kazuto Kamikura, Hiroshi Watanabe
  • Apparatus and method for simultaneous estimation of transfer characteristics of multiple linear transmission paths
    Patent number: 6785391
    Abstract: N correlated signals are processed by N pre-filters whose transfer characteristics have different zero points, then the processed signals are input into an N-input M-output linear FIR system, and its transfer characteristics are estimated from its response outputs and the processed signals from the pre-filters.
    Type: Grant
    Filed: May 21, 1999
    Date of Patent: August 31, 2004
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Satoru Emura, Masato Miyoshi
  • Optical device and three-dimensional display device
    Publication number: 20040164927
    Abstract: An optical device includes a transparent material layer having a desired curved surface configuration, a layer including a variable refractive index material having a dielectric constant anisotropy and having a property in which a sign of a difference &Dgr;&egr; in dielectric constant due to the anisotropy is reversed at driving frequencies f1 and f2, at least two transparent electrodes arranged to sandwich the transparent material layer and the layer including the variable refractive index material, and a driving device supplying a voltage including the driving frequencies f1 and f2 between the transparent electrodes.
    Type: Application
    Filed: February 23, 2004
    Publication date: August 26, 2004
    Applicant: Nippon Telegraph And Telephone Corporation
    Inventors: Shiro Suyama, Munekazu Date, Shigeto Kohda, Kinya Kato, Shigenobu Sakai
  • Optical packet routing network system based on optical label switching technique
    Patent number: 6782210
    Abstract: An optical communication equipment comprises shared optical sources 88a-88d to be shared by communication nodes 100a-100d, the wavelengths of optical signals 76a-76d are converted into desired wavelengths &lgr;a-&lgr;d according to the addressed information of the corresponding optical label signals 77a-77d by using the shared optical sources 88a-88d and routed to the addressed communication nodes without being converted into electrical signals by using the wavelength routing function of the cyclic-wavelength arrayed-waveguide grating (AWG) 120. The load of each communication node can be reduced by incorporating the multi-wavelength optical sources, which can be shared among individual communication nodes, into the router 80.
    Type: Grant
    Filed: August 23, 2000
    Date of Patent: August 24, 2004
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Akira Okada, Kazutoshi Kato, Kazuto Noguchi, Yoshihisa Sakai, Takashi Sakamoto, Morito Matsuoka, Sen-ichi Suzuki
  • Optical device and three-dimensional display device
    Publication number: 20040160389
    Abstract: An optical device includes a transparent material layer having a desired curved surface configuration, a layer including a variable refractive index material having a dielectric constant anisotropy, at least two transparent electrodes arranged to sandwich the transparent material layer and the variable refractive index material, and a driving device supplying a voltage including driving frequencies f1 and f2 between the transparent electrodes. The difference &Dgr;&egr; in the dielectric constant of the variable refractive index material due to the anisotropy is positive at one of the driving frequencies and negative at the other driving frequency.
    Type: Application
    Filed: February 23, 2004
    Publication date: August 19, 2004
    Applicant: Nippon Telegraph And Telephone Corporation
    Inventors: Shiro Suyama, Munekazu Date, Shigeto Kohda, Kinya Kato, Shigenobu Sakai
  • Optical fiber wiring apparatus and optical fiber wiring method
    Patent number: 6778754
    Abstract: A wiring substrate; a wiring head which guides optical fibers to the lead end thereof and forms an optical fiber path; an optical fiber feed mechanism which feeds the optical fiber into the optical fiber path; an optical fiber contact mechanism which brings the optical fiber, which has been guided to the lead end of the wiring head, and the wiring substrate into contact; an XY movement mechanism, which moves the wiring substrate and the wiring head relative to one anther in the X and Y directions; and an optical fiber affixing mechanism which successively affixes, to the wiring substrate, the optical fiber which has been brought into contact with the wiring substrate during movement by the XY movement mechanism; are provided.
    Type: Grant
    Filed: June 15, 2000
    Date of Patent: August 17, 2004
    Assignee: Nippon Telegraph & Telephone Corporation
    Inventors: Mamoru Hirayama, Koichi Arishima, Tsuneo Tamagaki, Masayuki Sasaki, Chikao Nakagawa
  • One-piece construction of plug frame for optical connector component
    Patent number: 6776535
    Abstract: A plug frame for an optical connector component comprising a ferrule for receiving an end portion of a core optical fiber of a fiber optic cable and a plug frame for floatingly supporting the ferrule. The plug frame is configured as a one-piece component. This allows reduction of the number of component parts and assembling steps, simplification of the assembling operations and reduction of the manufacturing cost.
    Type: Grant
    Filed: March 1, 2002
    Date of Patent: August 17, 2004
    Assignees: Hirose Electric Co., Ltd., Nippon Telegraph and Telephone Corporation, Honda Tsushin Kogyo Co., Ltd., Sanwa Denki Kogyo Co., Ltd.
    Inventors: Yukinori Miyake, Takumi Yoshida, Shin Sumida, Shuichi Yanagi, Yasuaki Ohkubo, Toshiaki Nakano, Yuji Shinagawa, Tatsuhito Shinozaki
  • Low-coherence reflectometer with polarization control
    Patent number: 6775005
    Abstract: A photocoupler 3 splits the light from a low-coherence light source 1 into measuring light DL and local oscillator light KL. A photocoupler 5 receives measuring light DL arid is input to an optical circuit 7 to be measured. The photocoupler 5 splits the reflected light RL. A polarization controller 9 controls the state of polarization of the reflected light RL as split by the photocoupler 5. A photocoupler 13 allows local oscillator light KL to be incident on a reflector mirror 16 and splits local oscillator light KL. A photocoupler 11 combines the reflected light RL as controlled in the state of polarization by the polarization controller 9, with the local oscillator light KL.
    Type: Grant
    Filed: February 25, 2002
    Date of Patent: August 10, 2004
    Assignees: Ando Electric Co., Ltd., Nippon Telegraph and Telephone Corporation
    Inventors: Fumio Akikuni, Shoichi Aoki, Tetsuo Yano, Tohru Mori, Kazumasa Takada
  • Silica-based optical waveguide circuit and fabrication method thereof
    Patent number: 6775454
    Abstract: A silica-based optical waveguide circuit serves to reduce the time required to production while allowing a spot size converting function to work sufficiently. In a silica-based optical waveguide circuit comprising an input/output waveguide core formed to be thicker than an waveguide core and a tapered portion for connecting the input/output waveguide core and the waveguide core, wherein the waveguide circuit further has a core layer at each side of the input/output waveguide core, a thickness T of the core layer at the side of the input/output waveguide core is smaller than the thickness H of the input/output waveguide core.
    Type: Grant
    Filed: May 9, 2002
    Date of Patent: August 10, 2004
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Mikitaka Itoh, Takashi Saida, Yasuhiro Hida, Yasuyuki Inoue
  • Polarization mode dispersion compensating device using optical XOR circuit
    Patent number: 6775426
    Abstract: A polarization mode dispersion compensating device is formed by a polarization mode dispersion equalizer, a polarization component splitting unit for splitting a part of the polarization mode dispersion compensated optical signal into the TE polarization component and the TM polarization component, an optical XOR circuit for carrying out an optical XOR operation on the TE polarization component and the TM polarization component, and a control system for controlling the polarization mode dispersion equalizer such that the logical operation result outputted by the optical XOR circuit becomes “0”.
    Type: Grant
    Filed: July 29, 2002
    Date of Patent: August 10, 2004
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Toshio Ito, Rieko Sato, Yasuhiro Suzuki
  • Semiconductor photo-detector, semiconductor photodetection device, and production methods thereof
    Patent number: 6770945
    Abstract: In a semiconductor photo-detector of the present invention, a first semiconductor layer, a second semiconductor layer having, and a photo-absorption part composed of a photo-absorption layer sandwiched between these layers are disposed on a substrate, at least the photo-absorption layer is formed at a position apart inwardly by a finite length from an end surface of the substrate, an end surface of the second semiconductor layer and the substrate or the end surface of the substrate is provided with a light incident facet angled inwardly as it separates from the surface of the second semiconductor or the surface of the substrate.
    Type: Grant
    Filed: December 4, 2001
    Date of Patent: August 3, 2004
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventor: Hideki Fukano
  • Optical fiber amplifier and optical communication system using the same
    Patent number: 6771414
    Abstract: This invention relates to the following four structures for attaining a flat gain spectrum over a wide wavelength region. The first structure relates to a Raman amplifier where a tellurite fiber is pumped with two wavelengths having a predetermined difference. The second structure relates to a Raman amplifier or an optical communication system employing a tellurite fiber and a silica fiber. The third structure relates to an optical fiber amplifier employing an Erbium-doped tellurite fiber of which Erbium concentration is low. The fourth structure relates to an optical fiber amplifier employing a rare-earth doped fiber such as the Erbium-doped fiber and a tellurite fiber.
    Type: Grant
    Filed: February 1, 2002
    Date of Patent: August 3, 2004
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Hiroji Masuda, Atsushi Mori, Makoto Shimizu
  • Semiconductor photo-detector, semiconductor photodetection device, and production methods thereof
    Publication number: 20040144912
    Abstract: In a semiconductor photo-detector of the present invention, a first semiconductor layer, a second semiconductor layer having, and a photo-absorption part composed of a photo-absorption layer sandwiched between these layers are disposed on a substrate, at least the photo-absorption layer is formed at a position apart inwardly by a finite length from an end surface of the substrate, an end surface of the second semiconductor-layer and the substrate or the end surface of the substrate is provided with a light incident facet angled inwardly as it separates from the surface of the second semiconductor or the surface of the substrate.
    Type: Application
    Filed: November 5, 2003
    Publication date: July 29, 2004
    Applicant: Nippon Telegraph and Telephone Corporation
    Inventor: Hideki Fukano
  • Optical packet routing network system based on optical label switching technique
    Publication number: 20040146300
    Abstract: An optical communication equipment comprises shared optical sources 88a-88d to be shared by communication nodes 100a-100d, the wavelengths of optical signals 76a-76d are converted into desired wavelengths &lgr;a-&lgr;d according to the addressed information of the corresponding optical label signals 77a-77d by using the shared optical sources 88a-88d, and routed to the addressed communication nodes without being converted into electrical signals by using the wavelength routing function of the cyclic-wavelength arrayed-waveguide grating (AWG) 120. The load of each communication node can be reduced by incorporating the multi-wavelength optical sources, which can be shared among individual communication nodes, into the router 80.
    Type: Application
    Filed: January 13, 2004
    Publication date: July 29, 2004
    Applicant: Nippon Telegraph and Telephone Corporation
    Inventors: Akira Okada, Kazutoshi Kato, Kazuto Noguchi, Yoshihisa Sakai, Takashi Sakamoto, Morito Matsuoka, Sen-ichi Suzuki
  • Image filling method, apparatus and computer readable medium for reducing filling process in processing animation
    Patent number: 6768488
    Abstract: An image filling method for reducing filling process in producing animation. The image filling method includes the steps of separating a reference line drawing and a line drawing into first and second closed regions; extracting at least one feature amount of the first and second closed regions; calculating variations of feature amounts between every combination of the first and second closed regions, sorting the first closed regions in ascending order by the variation of the feature amount for each of the second closed regions; generating color candidate lists for each of the second closed regions, wherein duplication of the color information is eliminated; filling each of the second closed regions with a color which is on the top of the color candidate list.
    Type: Grant
    Filed: May 24, 2000
    Date of Patent: July 27, 2004
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Naoya Kotani, Masakatsu Aoki, Kyoko Teranishi
  • Data converter and recording medium on which program for executing data conversion is recorded
    Patent number: 6769063
    Abstract: A plurality of round processing parts (38) are provided each of which contains a nonlinear function part (304), and each nonlinear function part (304) comprises: a first key-dependent linear transformation part (341) which performs a linear transformation based on a subkey; a splitting part (342) which splits the output from the first key-dependent linear transformation part into n pieces of subdata; a first nonlinear transformation part (343) which nonlinearly transforms those pieces of subdata, respectively; a second key-dependent linear transformation part (344) which linearly transforms those nonlinearly transformed outputs based on a subkey and outputs n pieces of transformed subdata; a second nonlinear transformation part (345) which nonlinearly transforms those transformed subdata; and a combining part (346) which combines the nonlinearly transformed outputs.
    Type: Grant
    Filed: September 14, 2000
    Date of Patent: July 27, 2004
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Masayuki Kanda, Youichi Takashima, Kazumaro Aoki, Hiroki Ueda, Kazuo Ohta, Tsutomu Matsumoto
  • Optical cable for holding optical fiber ribbons having a plurality of one groove spacers
    Patent number: 6768845
    Abstract: An optical cable has a plurality of one-groove spacers 3 which are twisted in one direction around a central member 1. Anti-tensile elements 2 are arranged in the central portion of the central member 1. Each one-groove spacer having a single groove which is linear lengthwise and substantially square in cross section and holding a stack of a plurality of optical fiber ribbons 4. The inner width and the height of the side walls of the groove of the one-groove spacer are set greater than the diagonal length of the stack. Therefore, the transmission loss becomes reducible because the contact portions of the optical fiber ribbons with respect to the side walls of the grooves vary in the longitudinal direction, thus preventing a specific number of optical fibers from being continuously subjected to edgewise pressure.
    Type: Grant
    Filed: February 17, 2000
    Date of Patent: July 27, 2004
    Assignees: Sumitomo Electric Industries, Ltd., Nippon Telegraph and Telephone Corporation
    Inventors: Yoshiyuki Suetsugu, Hiroki Ishikawa, Hideyuki Iwata
  • Optical packet routing network system based on optical label switching technique
    Publication number: 20040141743
    Abstract: An optical communication equipment comprises shared optical sources 88a-88d to be shared by communication nodes 100a-100d, the wavelengths of optical signals 76a-76d are converted into desired wavelengths &lgr;a-&lgr;d according to the addressed information of the corresponding optical label signals 77a-77d by using the shared optical sources 88a-88d, and routed to the addressed communication nodes without being converted into electrical signals by using the wavelength routing function of the cyclic-wavelength arrayed-waveguide grating (AWG) 120. The load of each communication node can be reduced by incorporating the multi-wavelength optical sources, which can be shared among individual communication nodes, into the router 80.
    Type: Application
    Filed: January 13, 2004
    Publication date: July 22, 2004
    Applicant: Nippon Telegraph and Telephone Corporation
    Inventors: Akira Okada, Kazutoshi Kato, Kazuto Noguchi, Yoshihisa Sakai, Takashi Sakamoto, Morito Matsuoka, Sen-ichi Suzuki