Patents Assigned to Nippon Telegraph & Telephone Corporation
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Patent number: 6469826Abstract: In the optical amplifier an optical divider based on long wavelength (or short wavelength) transmission type dielectric multi-layer filter divides input signal light according to wavelengths, and amplifying sections disposed in parallel and having different respective wavelength amplification regions respectively amplify light signals emitted from the optical divider, and an optical combiner based on long wavelength (or short wavelength) transmission type dielectric multi-layer filter combines light signals output from the respective amplifying sections. In another configuration of the optical amplifier, input signal light is divided using an optical divider based on a dielectric multi-layer filter of a long wavelength (or short wavelength) transmission type, and output signals from the divider are filtered using an optical filter connected in series to a short wavelength (or long wavelength) amplifier generating a loss in the long wavelength (or short wavelength) region of the light signals.Type: GrantFiled: July 10, 2000Date of Patent: October 22, 2002Assignee: Nippon Telegraph and Telephone CorporationInventors: Hiroji Masuda, Junichi Kani, Noboru Takachio
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Patent number: 6470017Abstract: A packet multiplexing apparatus is presented for multiplexing packets to be transmitted from a number of user facilities to a local service node in such a way to assure equal access to the output port for all the users. The apparatus is provided with input ports for inputting a packet in a respective input port; a buffer memory provided for each input port for temporary storage of a packet; an output signal transmission circuit for retrieving a packet from each buffer memory in a specific sequence; an output port for transmitting packets output from the output signal transmission circuit; and a retrieval sequencing section for controlling the specific sequence by changing a retrieving order of packets from buffer memories for each complete round of packet retrieval so that a frequency of the retrieving order for each input port is uniformly shared by the input ports.Type: GrantFiled: April 16, 1999Date of Patent: October 22, 2002Assignee: Nippon Telegraph and Telephone CorporationInventors: Akihiro Otaka, Noriki Miki, Norio Tamaki
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Patent number: 6470082Abstract: By using an external portable recording medium (for instance, IC card) that stores a personal ID, a communications apparatus automatically transmits the personal ID and its own terminal identification information to a center apparatus. The center apparatus manages the personal ID and the terminal identification information so that they are correlated with each other. For example, the terminal identification information includes a called-party address, a communication mode, and a position ID. Further, the center apparatus manages a present/absent mode for each personal ID. During the present mode, the center apparatus forwards a call using a personal telecommunication number, such as a UPT (universal personal telecommunication) number, which corresponds to a certain personal ID to a communications apparatus that corresponds to the personal ID. During the absent mode, the center apparatus automatically records a message.Type: GrantFiled: November 14, 2000Date of Patent: October 22, 2002Assignee: Nippon Telegraph and Telephone CorporationInventors: Ryozo Nunokawa, Hiroyuki Matsui, Satoru Abe, Yutaka Nishino
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Patent number: 6469528Abstract: An electro-optic sampling probe is disclosed, by which both faces of an IC wafer can be measured without moving the IC wafer. In the probe, an excitation optical system is provided at the back face side of a back-face excitation type IC wafer. The back face of the IC wafer is irradiated by light output from the excitation optical system, and simultaneously, the electric signal transmitted through wiring on the IC wafer is measured by using light output from an electro-optic sampling optical system provided at the front face side of the IC wafer. If the excitation optical system is substituted with an electro-optic sampling optical system, an IC wafer having wiring in both faces can also be measured.Type: GrantFiled: November 30, 1999Date of Patent: October 22, 2002Assignees: Ando Electric Co., Ltd., Nippon Telegraph and Telephone CorporationInventors: Fumio Akikuni, Katsushi Ohta, Mitsuru Shinagawa, Tadao Nagatsuma, Junzo Yamada
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Patent number: 6469683Abstract: An optical device includes a transparent 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;∈ 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 driving frequency.Type: GrantFiled: January 16, 1997Date of Patent: October 22, 2002Assignee: Nippon Telegraph and Telephone CorporationInventors: Shiro Suyama, Munekazu Date, Shigeto Kohda, Kinya Kato, Shigenobu Sakai
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Patent number: 6468895Abstract: In a pattern forming method, a trench is formed on a flat base. A pattern material is arranged only in and around the trench so as to project upward from the surface of the base and to be larger than the opening of the trench. The pattern material projecting from the surface of the base is removed by chemical mechanical polishing (CMP) so as to be flush with the upper surface of the base.Type: GrantFiled: April 3, 2001Date of Patent: October 22, 2002Assignee: Nippon Telegraph and Telephone CorporationInventors: Hiromu Ishii, Shouji Yagi, Katsuyuki Machida, Kunio Saito, Tadao Nagatsuma, Hakaru Kyuragi
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Patent number: 6463709Abstract: The present invention provides a transformable linked structure, a deployable diagonal structure, a plane stowage-type deployable truss and a line stowage-type deployable truss with high rigidity and reliability constituted by the above-described transformable linked structure and the above-described deployable diagonal structure, and also provides a plane/line stowage truss structure extremely approximated to a spherical surface using the two types of deployable trusses. The present invention discloses a module linked structure for linking deployable trusses securely and a holding/releasing mechanism for realizing reliable holding and release. Further, the present invention provides a modular deployable antenna with high precision even if it is large-sized which is realized by spreading mesh on the plane/line stowage truss structure.Type: GrantFiled: January 16, 2001Date of Patent: October 15, 2002Assignee: Nippon Telegraph and Telephone CorporationInventors: Akira Meguro, Jin Mitsugi, Kazuhide Ando
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Patent number: 6466714Abstract: The invention relates to a method of fabricating an optical fiber-processing phase mask in which a stitching error ascribable to a deterioration in the wavelength selectivity of the optical fiber diffraction grating to be fabricated is reduced. At an exposure step, a writing stage 5 with a phase mask blank 10 placed thereon is continuously fed in one direction while portions of the phase mask blank corresponding to grooves 26 or strips 27 in a direction perpendicular to the direction of feeding are sequentially scanned with writing beams 14, whereby the entire area of the phase mask blank 10 to be written is continuously written.Type: GrantFiled: April 27, 1999Date of Patent: October 15, 2002Assignee: Dai Nippon Printing Co., Ltd. and Nippon Telegraph and Telephone CorporationInventors: Masaaki Kurihara, Toshikazu Segawa, Tetsuro Komukai, Masataka Nakazawa
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Patent number: 6465880Abstract: An IC card whose state of usage can be judged by a user from an appearance of the card, and a relevant IC card system and method are provided. In an IC card fed electricity from an IC card reader-writer via feeding means using one of electromagnetic coupling and electrostatic coupling, and the IC card having an IC chip which communicates with the IC card reader-writer, the possible/impossible state of usage of the card by a user is determined using electric means for disconnecting or non-disconnecting the feeding means or providing another circuit and disconnecting this circuit, and appearance of the IC card is also changed at the time of the change caused by such electric means and thereby the state of usage of the card is indicated to the user.Type: GrantFiled: August 24, 1998Date of Patent: October 15, 2002Assignee: Nippon Telegraph and Telephone CorporationInventors: Hisanobu Dobashi, Shinji Nishimura, Toshinori Sonehara
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Patent number: 6462115Abstract: A water repellent coating composition includes fine particles having functional groups on their surfaces and having a particle diameter ranging from 10 nm to 1 mm; a coupling agent containing (a) a functional group which is capable of reacting with the functional group of the fine particles and (b) a water repellent fluorinated group; a binder resin for binding the fine particles; and a solvent for the binder.Type: GrantFiled: August 15, 1997Date of Patent: October 8, 2002Assignees: Nippon Telegraph and Telephone Corporation, NTT Advanced Technology CorporationInventors: Masaya Takahashi, Susumu Fujimori, Mamoru Ishitani, Taketoshi Matsuura, Hisao Tabei, Yoshiaki Haga, Akira Nohara, Nobuhiro Funakoshi
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Patent number: 6456380Abstract: A method for measuring a temporal waveform of the electric field of an optical signal avoids substantial sacrifice of sensitivity and enables accurate measuring of the ultra-fast temporal waveform of the electric field of the optical signal. It generates phase conjugated light by applying light whose phase is fixed with respect to optical signal to be measured; obtains spectral phase by observing mixed spectrum generated by combining the optical signal to be measured with the phase conjugated light; and obtains the temporal waveform of the electric field of the optical signal by attaching the spectral phase to a separately observed spectrum of the optical signal to be measured.Type: GrantFiled: May 15, 2000Date of Patent: September 24, 2002Assignee: Nippon Telegraph and Telephone CorporationInventor: Kazunori Naganuma
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Patent number: 6456760Abstract: An optical signal processing apparatus includes a first optical waveguide and a first slab waveguide configured to equally distribute an output light of the first optical waveguide. A first arrayed waveguide includes an aggregate of optical waveguides changing in optical length by a constant interval for dividing the output light. A second slab waveguide focuses the optical output of the first arrayed waveguide. A spatial filter receives incident light focused by the second slab waveguide and distributes the incident light on a straight line. The spatial filter also modulates the light into a desired amplitude according to the position on the straight line. The apparatus also includes a second arrayed waveguide and an aggregate of optical waveguides changing in optical length by a constant interval for applying light modulated by the spatial filter to the second arrayed waveguide. Structure is provided for converging the output light of said second arrayed waveguide to a single point.Type: GrantFiled: February 24, 2000Date of Patent: September 24, 2002Assignee: Nippon Telegraph and Telephone CorporationInventors: Takashi Kurokawa, Hiroyuki Tsuda, Katsunari Okamoto, Kazunori Naganuma, Tetsuyoshi Ishii, Hirokazu Takenouchi
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Patent number: 6456658Abstract: A moving image brightness variation compensation method for encoding digital moving images for transmission and storage, and for image processing when editing moving images, the moving image brightness variation compensation method comprising a step of compensating for overall brightness variations by correcting a luminance value x of each pixel according to the formula DC·x+DB, wherein DB is a parameter indicating a gain change and DC is a parameter indicating a contrast change, the parameters representing overall luminance changes between a reference image plane and an image plane being processed.Type: GrantFiled: April 11, 2001Date of Patent: September 24, 2002Assignee: Nippon Telegraph and Telephone CorporationInventors: Kazuto Kamikura, Hiroshi Watanabe, Hirohisa Jozawa
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Patent number: 6456405Abstract: A method for displaying computer generated holograms of a display object is performed by computing fringe patterns produced by light interference from the display object. The steps are summarized as follows: three-dimensional data of the display object are converted into computational data for fringe pattern generation; a sampling rule for sampling computational data is selected; computational data are sampled according to a selected sampling rule; wavefronts generated by light illumination are computed by assuming that each sampled position has a light source; fringe patterns generated by computed wavefronts and a reference beam are computed; fringe patterns are stored as hologram images; sampling and a wavefront generation are repeated for all data; and a series of hologram images thus generated are displayed successively.Type: GrantFiled: September 28, 2001Date of Patent: September 24, 2002Assignee: Nippon Telegraph and Telephone CorporationInventors: Tsutomu Horikoshi, Kazuhito Higuchi, Takaaki Akimoto, Satoshi Suzuki
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Patent number: 6452378Abstract: An electro-optic sampling probe is provided, capable of irradiating a plurality of excitation light beams on a plurality of light receiving portions mounted on an IC wafer which is an object for measurement. The electro-optic sampling probe comprises a plurality of excitation optical system modules which commonly uses an objective lens for condensing the excitation light beams on the IC wafer and a detachable portion for attaching and detaching the excitation optical system module, a second probe body for covering the optical path of a light beam emitted from the excitation optical system module is provided at the rear side of the IC wafer, and at least one of the plurality of excitation optical system modules have an optical axis which differs from those of other modules; thereby at least two excitation light beams can be irradiated on the light receiving portions on the IC wafer surface.Type: GrantFiled: May 18, 2000Date of Patent: September 17, 2002Assignees: Ando Electric Co., Ltd., Nippon Telegraph and Telephone CorporationInventors: Noriyuki Toriyama, Toshiyuki Yagi, Tadao Nagatsuma
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Publication number: 20020126933Abstract: An interferometer includes a waveguide core, and thin film heaters with widths W1 and W2. The thin film heaters are mounted directly above the waveguide core, and operate as two types of different annealing regions. The annealing, which is carried out by supplying current to the thin film heaters, can alter the quality of the cladding, and change the stress applied on the waveguide core, thereby making it possible to control the polarization dependency. Thus changing the width of the thin film heaters and/or the amount of the supply current thereto enables the permanent control of the effective refractive index (birefringence index) independently in the transverse electric polarization mode and the transverse magnetic polarization mode. This enables the transverse electric polarization mode to be adjusted to a phase difference of &lgr;/2, and the transverse magnetic polarization mode to a phase difference of zero.Type: ApplicationFiled: January 22, 2002Publication date: September 12, 2002Applicant: Nippon Telegraph and Telephone CorporationInventors: Takashi Goh, Makoto Abe, Yasuyuki Inoue, Masayuki Okuno, Takashi Saida
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Publication number: 20020126352Abstract: An optical signal quality degradation monitoring apparatus for monitoring an optical wavelength division multiplex signal is implemented in a small size. To monitor the optical signal quality degradation in the optical wavelength division multiplex signal by a configuration as simple as possible, the following configurations are used: A configuration using an optical wavelength division demultiplexer and a sampling clock generator to make one an electric signal processor; A configuration using an optical sampling pulse train generator, an optical multiplexer, a nonlinear optical medium, and an optical wavelength division demultiplexer to make one an electric signal processor; or a configuration using a selection wavelength control section, an optical wavelength selecting section, and a sampling clock generator to make one electric signal.Type: ApplicationFiled: March 7, 2002Publication date: September 12, 2002Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Ippei Shake, Hidehiko Takara
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Publication number: 20020126341Abstract: A part of a wavelength division multiplexed optical signal output from a multiplexing area is extracted as a check signal, and then the extracted signal is guided to a multiplexing area. A reentered check signal is detected at a facet located opposite a facet from which the check signal has been reentered, and the state of the detected check signal is determined. Furthermore at need, on the basis of the result of the determination, a control signal is output that controls operations of a plurality of optical signals input to the multiplexing area.Type: ApplicationFiled: February 26, 2002Publication date: September 12, 2002Applicant: NTT ELECTRONICS CORPORATION and NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Yoshiki Yamauchi, Kouichi Fujisaki, Akimasa Kaneko, Takashi Asaoka, Yoshihisa Sakai
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Patent number: 6445845Abstract: An optical switch for switching a light path between two optical waveguides is provided. The switch has a slit formed diagonally cutting across the crossing point of crossing optical waveguides and a substance in the slit has a function of transmitting or reflecting an optical signal is selectively held in the slit. The slit is narrower than cores of the optical waveguides, and has a center line formed on a bisection of an interior angle between optical axes of the crossing optical waveguides. Thus, the substance in the slit serves to make optical intensity reflected to each of the optical waveguides uniform. Further, a crossing optical waveguide consists of a reflecting structure having its interior filled with air during reflection and the intersecting angle between the first group of optical waveguides is between 0 to 90 degrees and preferably substantially between 73 and 74 degrees.Type: GrantFiled: April 26, 2000Date of Patent: September 3, 2002Assignee: Nippon Telegraph and Telephone CorporationInventors: Tomomi Sakata, Hiroyoshi Togo, Fusao Shimokawa, Mitsuhiro Makihara
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Patent number: 6445198Abstract: An electro-optic sampling probe includes an electro-optic element which is to be positioned to contact wiring on an IC wafer surface which is a measurement target and whose optical characteristics are changed depending on an electric field applied via the wiring and an electro-optic sampling optical system module having a polarized beam splitter, a wave plate, and a photo diode. The module separates light, which is transmitted through the electro-optic element and is reflected by a surface of the electro-optic element from laser light emitted from the outside and converts the separated light into an electric signal, and includes an optical axis adjuster attached to a detachable portion of an optical fiber that emits the laser light for adjusting the optical axis of the laser light and a light receiving surface adjuster attached to the detachable portion of the photo diode for adjusting the position of a light receiving surface of the photo diode.Type: GrantFiled: April 3, 2000Date of Patent: September 3, 2002Assignees: Ando Electric Co., Ltd., Nippon Telegraph and Telephone CorporationInventors: Fumio Akikuni, Katsushi Ohta, Tadao Nagatsuma, Mitsuru Shinagawa, Junzo Yamada