Patents by Inventor Masamichi Fujiwara
Masamichi Fujiwara 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).
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Publication number: 20190377636Abstract: In general, according to an embodiment, a memory system includes a memory device including a memory cell; and a controller. The controller is configured to: receive first data from the memory cell in a first data reading; receive second data from the memory cell in a second data reading that is different from the first data reading; convert a first value that is based on the first data and the second data, to a second value in accordance with a first relationship; and convert the first value to a third value in accordance with a second relationship that is different from the first relationship.Type: ApplicationFiled: August 21, 2019Publication date: December 12, 2019Applicant: Toshiba Memory CorporationInventors: Tsukasa TOKUTOMI, Masanobu SHIRAKAWA, Marie TAKADA, Masamichi FUJIWARA, Kazumasa YAMAMOTO, Naoaki KOKUBUN, Tatsuro HITOMI, Hironori UCHIKAWA
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Patent number: 10430275Abstract: In general, according to an embodiment, a memory system includes a memory device including a memory cell; and a controller. The controller is configured to: receive first data from the memory cell in a first data reading; receive second data from the memory cell in a second data reading that is different from the first data reading; convert a first value that is based on the first data and the second data, to a second value in accordance with a first relationship; and convert the first value to a third value in accordance with a second relationship that is different from the first relationship.Type: GrantFiled: March 9, 2018Date of Patent: October 1, 2019Assignee: Toshiba Memory CorporationInventors: Tsukasa Tokutomi, Masanobu Shirakawa, Marie Takada, Masamichi Fujiwara, Kazumasa Yamamoto, Naoaki Kokubun, Tatsuro Hitomi, Hironori Uchikawa
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Publication number: 20190087264Abstract: In general, according to an embodiment, a memory system includes a memory device including a memory cell; and a controller. The controller is configured to: receive first data from the memory cell in a first data reading; receive second data from the memory cell in a second data reading that is different from the first data reading; convert a first value that is based on the first data and the second data, to a second value in accordance with a first relationship; and convert the first value to a third value in accordance with a second relationship that is different from the first relationship.Type: ApplicationFiled: March 9, 2018Publication date: March 21, 2019Applicant: Toshiba Memory CorporationInventors: Tsukasa Tokutomi, Masanobu Shirakawa, Marie Takada, Masamichi Fujiwara, Kazumasa Yamamoto, Naoaki Kokubun, Tatsuro Hitomi, Hironori Uchikawa
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Patent number: 9306670Abstract: The present invention relates to an optical coupling/splitting device that realizes the splitting of a down-signal and the coupling of up-signals by the same optical device, and reduces coupling losses of the up-signal. An optical coupling/splitting device in the present invention comprises an optical coupling/splitting means for coupling a plurality of up-signals in a multi-mode for output and splitting a down-signal in a single mode for output, and a two-way optical propagation means for propagating the up-signal that is output from the optical coupling/splitting means in a multi-mode for output and propagate the down-signal in a single mode to be output to the optical coupling/splitting means.Type: GrantFiled: September 27, 2012Date of Patent: April 5, 2016Assignee: Nippon Telegraph and Telephone CorporationInventors: Masamichi Fujiwara, Kenichi Suzuki, Naoto Yoshimoto, Manabu Oguma, Toshio Watanabe, Hiroshi Takahashi, Hiromasa Tanobe, Tsutomu Kitoh
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Publication number: 20140186040Abstract: The present invention relates to an optical coupling/splitting device that realizes the splitting of a down-signal and the coupling of up-signals by the same optical device, and reduces coupling losses of the up-signal. An optical coupling/splitting device in the present invention comprises an optical coupling/splitting means for coupling a plurality of up-signals in a multi-mode for output and splitting a down-signal in a single mode for output, and a two-way optical propagation means for propagating the up-signal that is output from the optical coupling/splitting means in a multi-mode for output and propagate the down-signal in a single mode to be output to the optical coupling/splitting means.Type: ApplicationFiled: September 27, 2012Publication date: July 3, 2014Inventors: Masamichi Fujiwara, Kenichi Suzuki, Naoto Yoshimoto, Manabu Oguma, Toshio Watanabe, Hiroshi Takahashi, Hiromasa Tanobe, Tsutomu Kitoh
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Patent number: 7474460Abstract: An optical modulation apparatus is provided which implements a stable amplifying function by reducing the effect of reflected light rays from end faces of a bidirectional optical amplifier by imposing a numerical limitation on the relationship between the gain of the bidirectional optical amplifier and the loss of the optical modulator, or by inserting a polarization rotation section in a reflection type optical modulator including the bidirectional optical amplifier or in a multi-wavelength collective optical modulation system combining the multiple optical modulators. An optical modulation apparatus is provided which implements a stable amplifying function and cost reduction by reducing the effect of reflected light rays by interposing optical isolators at every alternate SOAs in a transmission-type optical modulation apparatus including a plurality of semiconductor optical amplifiers (SOAs) connected in a multistage fashion.Type: GrantFiled: February 13, 2007Date of Patent: January 6, 2009Assignee: Nippon Telegraph and Telephone Corporation.Inventors: Masamichi Fujiwara, Junichi Kani, Koji Akimoto, Katsumi Iwatsuki
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Patent number: 7336414Abstract: An optical modulation apparatus is provided which implements a stable amplifying function by reducing the effect of reflected light rays form end faces of a bidirectional optical amplifier by imposing a numerical limitation on the relationship between the gain of the bidirectional optical amplifier and the loss of the optical modulator, or by inserting a polarization rotation section in a reflection type optical modulator including the bidirectional optical amplifier or in a multi-wavelength collective optical modulation system combining the multiple optical modulators. An optical modulation apparatus is provided which implements a stable amplifying function and cost reduction by reducing the effect of reflected light rays by interposing optical isolators at every alternate SOAs in a transmission-type optical modulation apparatus including a plurality of semiconductor optical amplifiers (SOAs) connected in a multistage fashion.Type: GrantFiled: June 16, 2004Date of Patent: February 26, 2008Assignee: Nippon Telegraph and Telephone CorporationInventors: Masamichi Fujiwara, Junichi Kani, Koji Akimoto, Katsumi Iwatsuki
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Publication number: 20070127113Abstract: An optical modulation apparatus is provided which implements a stable amplifying function by reducing the effect of reflected light rays from end faces of a bidirectional optical amplifier by imposing a numerical limitation on the relationship between the gain of the bidirectional optical amplifier and the loss of the optical modulator, or by inserting a polarization rotation section in a reflection type optical modulator including the bidirectional optical amplifier or in a multi-wavelength collective optical modulation system combining the multiple optical modulators. An optical modulation apparatus is provided which implements a stable amplifying function and cost reduction by reducing the effect of reflected light rays by interposing optical isolators at every alternate SOAs in a transmission-type optical modulation apparatus including a plurality of semiconductor optical amplifiers (SOAs) connected in a multistage fashion.Type: ApplicationFiled: February 13, 2007Publication date: June 7, 2007Applicant: Nippon Telegraph and Telephone CorporationInventors: Masamichi Fujiwara, Junichi Kani, Koji Akimoto, Katsumi Iwatsuki
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Patent number: 7206510Abstract: A first optical fiber transmission path is used to transmit continuous-wave light for upstream signal light from the center node to each of the remote nodes, while a second optical fiber transmission path is used to transmit downstream signal light from the center node to each remote node and to transmit upstream signal light (obtained by modulating continuous-wave light) from each remote node to the center node. In this network, specific wavelength bandwidths are allocated to each remote node for the continuous-wave lights (for upstream signal lights) and the downstream signal lights, and the wavelength bandwidths for the continuous-wave lights (for upstream signal lights) and the downstream signal lights are alternately set.Type: GrantFiled: October 8, 2002Date of Patent: April 17, 2007Assignee: Nippon Telegraph and Telephone CorporationInventors: Hiroo Suzuki, Masamichi Fujiwara, Mitsuhiro Teshima, Koji Akimoto, Shingo Kawai, Jun-ichi Kani, Noboru Takachio, Katsumi Iwatsuki
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Patent number: 7127168Abstract: Multi-wavelength light having a frequency band equal to or greater than the FSR of an AWG is demultiplexed into individual wavelength channels, and power level deviations between wavelength channels are suppressed. An optical demultiplexer includes a wavelength-group demultiplexer that demultiplexes multi-wavelength light into wavelength groups formed from wavelength channels, and channel demultiplexers that demultiplex each wavelength group into wavelength channels light. An optical multiplexer includes channel multiplexers that multiplex modulated signal light of each wavelength channel for each wavelength group, and a wavelength-group multiplexer that multiplexes, for each wavelength group, WDM signal light output from the channel multiplexers. The FSR of the wavelength-group multiplexer/demultiplexer is set to be equal to or greater than the frequency band of the multi-wavelength light.Type: GrantFiled: June 5, 2002Date of Patent: October 24, 2006Assignee: Nippon Telegraph and Telephone CorporationInventors: Jun-ichi Kani, Katsuhiro Araya, Noboru Takachio, Koji Akimoto, Mitsuhiro Teshima, Masamichi Fujiwara, Hiroo Suzuki, Shingo Kawai, Katsumi Iwatsuki
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Patent number: 7106970Abstract: To generate light with the degree of polarization zeroed and the spread of an optical spectrum suppressed even with temporal overlapping between optical pulses each of which is polarized orthogonally to the succeeding pulse, a polarization scrambler includes an optical pulse generator that generates optical pulses with an intensity waveform repetition period T/2 and an electrical field repetition period T in which the same intensity waveform is repeated every repetition period T/2 and in which phase is inverted every repetition period T/2, and an orthogonal polarization delay unit which receives each of the optical pulses, separates the optical pulse into two optical pulses with orthogonal states of polarization, and relatively shifts the temporal position of one of the two optical pulses from that of the other optical pulse by (2n?1)T/4 (n is a natural number) to generate light in which each pulse is polarized orthogonally to a succeeding pulse.Type: GrantFiled: May 20, 2005Date of Patent: September 12, 2006Assignee: Nippon Telegraph and Telephone CorporationInventors: Masamichi Fujiwara, Mitsuhiro Teshima, Noboru Takachio, Katsumi Iwatsuki
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Patent number: 7068412Abstract: With respect to the relative intensity noise (RIN) for inputs to an optical modulator or the signal-to-noise ratio (SNR) for outputs therefrom, the optical modulator modulating coherent lights of different wavelengths obtained by slicing a spectrum of the multi-wavelength light, the shape of a spectrum of a multi-wavelength light is controlled so that predetermined RIN and SNR can be obtained in accordance with transmission system parameters (the type and distance of optical fibers, the number of repeaters), thus enabling design meeting a performance specification for a conventional transmission section using semiconductor lasers.Type: GrantFiled: April 16, 2004Date of Patent: June 27, 2006Assignee: Nippon Telegraph and Telephone Corp.Inventors: Masamichi Fujiwara, Katsuhiro Araya, Mitsuhiro Teshima, Junichi Kani, Kenichi Suzuki
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Patent number: 7031614Abstract: To generate light with the degree of polarization zeroed and the spread of an optical spectrum suppressed even with temporal overlapping between optical pulses each of which is polarized orthogonally to the succeeding pulse, a polarization scrambler includes an optical pulse generator that generates optical pulses with an intensity waveform repetition T/2 and an electrical field repetition period T in which the same intensity waveform is repeated every repetition period T/2 and in which phase is inverted every repetition period T/2, and an orthogonal polarization delay unit which receives each of the optical pulses, separates the optical pulse into two optical pulses with orthogonal states of polarization, and relatively shifts the temporal position of one of the two optical pulses from that of the other optical pulse by (2n?1)T/4 (n is a natural number) to generate light in which each pulse is polarized orthogonally to a succeeding pulse.Type: GrantFiled: May 19, 2005Date of Patent: April 18, 2006Assignee: Nippon Telegraph and Telephone CorporationInventors: Masamichi Fujiwara, Mitsuhiro Teshima, Noboru Takachio, Katsumi Iwatsuki
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Publication number: 20060024066Abstract: An optical modulation apparatus is provided which implements a stable amplifying function by reducing the effect of reflected light rays form end faces of a bidirectional optical amplifier by imposing a numerical limitation on the relationship between the gain of the bidirectional optical amplifier and the loss of the optical modulator, or by inserting a polarization rotation section in a reflection type optical modulator including the bidirectional optical amplifier or in a multi-wavelength collective optical modulation system combining the multiple optical modulators. An optical modulation apparatus is provided which implements a stable amplifying function and cost reduction by reducing the effect of reflected light rays by interposing optical isolators at every alternate SOAs in a transmission-type optical modulation apparatus including a plurality of semiconductor optical amplifiers (SOAs) connected in a multistage fashion.Type: ApplicationFiled: June 16, 2004Publication date: February 2, 2006Inventors: Masamichi Fujiwara, Junichi Kani, Koji Akimoto, Katsumi Iwatsuki
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Patent number: 6959152Abstract: To generate light with the degree of polarization zeroed and the spread of an optical spectrum suppressed even with temporal overlapping between optical pulses each of which is polarized orthogonally to the succeeding pulse, a polarization scrambler includes an optical pulse generator that generates optical pulses with an intensity waveform repetition period T/2 and an electrical field repetition period T in which the same intensity waveform is repeated every repetition period T/2 and in which phase is inverted every repetition period T/2, and an orthogonal polarization delay unit which receives each of the optical pulses, separates the optical pulse into two optical pulses with orthogonal states of polarization, and relatively shifts the temporal position of one of the two optical pulses from that of the other optical pulse by (2n?1)T/4 (n is a natural number) to generate light in which each pulse is polarized orthogonally to a succeeding pulse.Type: GrantFiled: February 20, 2003Date of Patent: October 25, 2005Assignee: Nippon Telegraph and Telephone CorporationInventors: Masamichi Fujiwara, Mitsuhiro Teshima, Noboru Takachio, Katsumi Iwatsuki
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Publication number: 20050220457Abstract: To generate light with the degree of polarization zeroed and the spread of an optical spectrum suppressed even with temporal overlapping between optical pulses each of which is polarized orthogonally to the succeeding pulse, a polarization scrambler includes an optical pulse generator that generates optical pulses with an intensity waveform repetiton period T/2 and an electrical field repetition period T in which the same intensity waveform is repeated every repetition period T/2 and in which phase is inverted every repetition period T/2, and an orthogonal polarization delay unit which receives each of the optical pulses, separates the optical pulse into two optical pulses with ortogonal states of polarization, and relatively shifts the temporal position of one of the two optical pulses from that of the other optical pulse by (2n?1)T/4 (n is a natural number) to generate light in which each pulse is polarized orthogonally to a succeeding pulse.Type: ApplicationFiled: May 20, 2005Publication date: October 6, 2005Inventors: Masamichi Fujiwara, Mitsuhiro Teshima, Noboru Takachio, Katsumi Iwatsuki
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Publication number: 20050213991Abstract: To generate light with the degree of polarization zeroed and the spread of an optical spectrum suppressed even with temporal overlapping between optical pulses each of which is polarized orthogonally to the succeeding pulse, a polarization scrambler includes an optical pulse generator that generates optical pulses with an intensity waveform repetition T/2 and an electrical field repetition period T in which the same intensity waveform is repeated every repetition period T/2 and in which phase is inverted every repetition period T/2, and an orthogonal polarization delay unit which receives each of the optical pulses, separates the optical pulse into two optical pulses with orthogonal states of polarization, and relatively shifts the temporal position of one of the two optical pulses from that of the other optical pulse by (2n?1)T/4 (n is a natural number) to generate light in which each pulse is polarized orthogonally to a succeeding pulse.Type: ApplicationFiled: May 19, 2005Publication date: September 29, 2005Inventors: Masamichi Fujiwara, Mitsuhiro Teshima, Noboru Takachio, Katsumi Iwatsuki
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Patent number: 6924924Abstract: A multi-wavelength generating apparatus generates a wavelength division multiplexing (WDM) signal by modulating light with a single central frequency and with an electric signal having a particular pulse repetition frequency. The resulting optical spectrum configuration is controllable so that a Relative Intensity Noise (RIN) or Signal to Noise Ratio (SNR) requirement may be achieved. A modulated or pulsed light source is used to obtain a discrete spectrum with particular mode spacing, which is then modulated to permit dynamic power control for specific modes of the discrete spectrum.Type: GrantFiled: September 4, 2003Date of Patent: August 2, 2005Assignee: Nippon Telegraph and Telephone CorporationInventors: Masamichi Fujiwara, Katsuhiro Araya, Mitsuhiro Teshima, Junichi Kani, Kenichi Suzuki
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Publication number: 20050008373Abstract: With respect to the relative intensity noise (RIN) for inputs to an optical modulator or the signal-to-noise ratio (SNR) for outputs therefrom, the optical modulator modulating coherent lights of different wavelengths obtained by slicing a spectrum of the multi-wavelength light, the shape of a spectrum of a multi-wavelength light is controlled so that predetermined RIN and SNR can be obtained in accordance with transmission system parameters (the type and distance of optical fibers, the number of repeaters), thus enabling design meeting a performance specification for a conventional transmission section using semiconductor lasers.Type: ApplicationFiled: April 16, 2004Publication date: January 13, 2005Inventors: Masamichi Fujiwara, Katsuhiro Araya, Mitsuhiro Teshima, Junichi Kani, Kenichi Suzuki
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Patent number: 6831774Abstract: Amulti-wavelength generating apparatus generates a wavelength division multiplexing (WDM) signal by modulating light with a single central frequency and an electric signal having a particular pulse repetition frequency. The resulting optical spectrum configuration is conntrollable so that a Relative Intensity Noise (RIN) or Signal to Noise Ratio (SNR) requirement may be achieved. A modulated or pulsed light source in used to obtain a descrete spectrum with particular mode spacing, which is then modulated to permit dynamic power control for specific modes of the discrete spectrum.Type: GrantFiled: July 6, 2001Date of Patent: December 14, 2004Assignee: Nippon Telegraph and Telephone CorporationInventors: Masamichi Fujiwara, Katsuhiro Araya, Mitsuhiro Teshima, Junichi Kani, Kenichi Suzuki