Patents by Inventor Kengo Horikoshi

Kengo Horikoshi 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: 20210218471
    Abstract: A reception apparatus includes a dispersion compensation unit configured to acquire an electrical signal resulting from conversion of an optical signal and perform, on the electrical signal, dispersion compensation with a predetermined compensation amount, a clip rate measurement unit configured to measure a clip rate for the electrical signal subjected to the dispersion compensation, and a control unit configured to detect the compensation amount that minimizes the clip rate.
    Type: Application
    Filed: May 8, 2019
    Publication date: July 15, 2021
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Seiji OKAMOTO, Masanori NAKAMURA, Kengo HORIKOSHI
  • Publication number: 20210041631
    Abstract: A fiber module (1B) according to the present disclosure includes an input-side optical fiber (11), an output-side optical fiber (12), a ferrule (20) in which the input-side optical fiber and the output-side optical fiber are insertable in both ends and a groove (32) is formed in a direction orthogonal to a longitudinal direction (D1) in the middle of the longitudinal direction, a dielectric multilayer film filter (30) inserted in the groove, and an input-side GI fiber (15) and an output-side GI fiber (16) joined by fusion to respective terminal portions of the input-side optical fiber and the output-side optical fiber. The dielectric multilayer film filter is interposed between an end surface (15f) of the input-side GI fiber and an end surface (16f) of the output-side GI fiber in the longitudinal direction.
    Type: Application
    Filed: February 28, 2019
    Publication date: February 11, 2021
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Kengo HORIKOSHI, Takashi YAMADA, Hisao YOSHINAGA, Shunsuke KANAI, Manabu KUBOTA
  • Publication number: 20210006032
    Abstract: A method for manufacturing a monolithically integrated semiconductor optical integrated element comprising a DFB laser, an EA modulator, and a SOA disposed in a light emitting direction, comprising the step of forming a semiconductor wafer on which the elements are two-dimensionally arrayed and aligned the optical axes; cleaving the semiconductor wafer along a plane orthogonal to the light emitting direction to form a semiconductor bar including a plurality of the elements arranged one-dimensionally along a direction orthogonal to the light emitting direction such that the elements adjacent to each other share an identical cleavage end face as a light emission surface; inspecting the semiconductor bar by driving the SOA and the DFB laser through a connection wiring part together; and separating out the semiconductor bar after the inspection to cut the connection wiring part connecting the electrode of the SOA and the DFB laser to isolate from each other.
    Type: Application
    Filed: February 28, 2019
    Publication date: January 7, 2021
    Inventors: Takahiko Shindo, Naoki Fujiwara, Kimikazu Sano, Hiroyuki Ishii, Hideaki Matsuzaki, Takashi Yamada, Kengo Horikoshi
  • Patent number: 10841006
    Abstract: A signal-to-noise ratio (SNR) estimation method includes an optical signal transmission step of inserting at least one pair of signal sequences into transmission data and transmitting the transmission data into which the at least one pair of signal sequences is inserted, a signal sequence extraction step of extracting the at least one pair of signal sequences from a received signal obtained by receiving the transmitted transmission data, an inner product calculation step of calculating an inner product value of the extracted at least one pair of signal sequences, a reception power calculation step of calculating reception power of the extracted at least one pair of signal sequences, and an SNR calculation step of calculating an SNR of the at least one pair of signal sequences on the basis of the calculated inner product value and the calculated reception power.
    Type: Grant
    Filed: March 26, 2018
    Date of Patent: November 17, 2020
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Seiji Okamoto, Yoshiaki Kisaka, Kengo Horikoshi, Mitsuteru Yoshida, Masahiro Suzuki
  • Patent number: 10826620
    Abstract: An optical receiver that demodulates an optical modulation signal into a baseband signal, which is an electrical signal, and decodes a received symbol acquired by converting the baseband signal. The optical receiver includes: an analog-to-digital converter that converts the baseband signal into a digital signal of which the number of samples per received symbol is M/N (samples/symbol), M and N being positive integers, M/N being not an integer, and “M>N” being satisfied; and an adaptive equalization processing unit that executes an equalization operation set in advance to output the received symbol on the basis of the digital signal of which the number of samples per received symbol is M/N (samples/symbol) and a predetermined tap coefficient digital signal equalization tap coefficients used for equalization of a signal, the coefficient being updated in any sampling period.
    Type: Grant
    Filed: October 25, 2017
    Date of Patent: November 3, 2020
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Fukutaro Hamaoka, Seiji Okamoto, Masanori Nakamura, Kengo Horikoshi, Yoshiaki Kisaka
  • Patent number: 10651944
    Abstract: An optical transmitter of an optical data transmission system transmitting data through an optical fiber transmission path includes a main signal generator that converts first transmission data into a predetermined signal format to generate a first signal, a DCSK modulator that DCSK-modulates second transmission data to generate a second signal, a signal-multiplexer that performs time-division multiplexing of the first signal and the second signal, and an electro-optical converter that converts a multiplexed signal obtained by the time-division multiplexing of the signal-multiplexer from an electric signal into an optical signal, and outputs the optical signal to the optical fiber transmission path.
    Type: Grant
    Filed: July 26, 2017
    Date of Patent: May 12, 2020
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Kengo Horikoshi, Seiji Okamoto, Asuka Matsushita, Mitsuteru Yoshida, Fukutaro Hamaoka, Yoshiaki Yamada, Yoshiaki Kisaka
  • Publication number: 20200052793
    Abstract: An optical receiver that demodulates an optical modulation signal into a baseband signal, which is an electrical signal, and decodes a received symbol acquired by converting the baseband signal. The optical receiver includes: an analog-to-digital converter that converts the baseband signal into a digital signal of which the number of samples per received symbol is M/N (samples/symbol), M and N being positive integers, M/N being not an integer, and “M >N” being satisfied; and an adaptive equalization processing unit that executes an equalization operation set in advance to output the received symbol on the basis of the digital signal of which the number of samples per received symbol is M/N (samples/symbol) and a predetermined tap coefficient digital signal equalization tap coefficients used for equalization of a signal, the coefficient being updated in any sampling period.
    Type: Application
    Filed: October 25, 2017
    Publication date: February 13, 2020
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Fukutaro HAMAOKA, Seiji OKAMOTO, Masanori NAKAMURA, Kengo HORIKOSHI, Yoshiaki KISAKA
  • Publication number: 20200028586
    Abstract: A signal-to-noise ratio (SNR) estimation method includes an optical signal transmission step of inserting at least one pair of signal sequences into transmission data and transmitting the transmission data into which the at least one pair of signal sequences is inserted, a signal sequence extraction step of extracting the at least one pair of signal sequences from a received signal obtained by receiving the transmitted transmission data, an inner product calculation step of calculating an inner product value of the extracted at least one pair of signal sequences, a reception power calculation step of calculating reception power of the extracted at least one pair of signal sequences, and an SNR calculation step of calculating an SNR of the at least one pair of signal sequences on the basis of the calculated inner product value and the calculated reception power.
    Type: Application
    Filed: March 26, 2018
    Publication date: January 23, 2020
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Seiji OKAMOTO, Yoshiaki KISAKA, Kengo HORIKOSHI, Mitsuteru YOSHIDA, Masahiro SUZUKI
  • Patent number: 10422719
    Abstract: A Fourier-transformer performs Fourier transform on a filter coefficient output from an adaptive equalizer which comprises a finite impulse response filter of N taps (N represents an integer of 2 or more) in a time direction. An eigenvalue sum calculator integrates a frequency-differentiation result of the Fourier-transformed filter coefficient and a complex conjugate of the Fourier-transformed filter coefficient to calculate a matrix, and calculates a sum of two eigenvalues of the matrix. A proportionality factor calculator calculates a proportionality factor for frequency from the sum of the two eigenvalues.
    Type: Grant
    Filed: October 4, 2016
    Date of Patent: September 24, 2019
    Assignees: NTT ELECTRONICS CORPORATION, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Etsushi Yamazaki, Tomohiro Takamuku, Yuki Yoshida, Mitsuteru Yoshida, Koki Shibahara, Kengo Horikoshi, Yoshiaki Kisaka
  • Publication number: 20190273560
    Abstract: An optical transmitter of an optical data transmission system transmitting data through an optical fiber transmission path includes a main signal generator that converts first transmission data into a predetermined signal format to generate a first signal, a DCSK modulator that DCSK-modulates second transmission data to generate a second signal, a signal-multiplexer that performs time-division multiplexing of the first signal and the second signal, and an electro-optical converter that converts a multiplexed signal obtained by the time-division multiplexing of the signal-multiplexer from an electric signal into an optical signal, and outputs the optical signal to the optical fiber transmission path.
    Type: Application
    Filed: July 26, 2017
    Publication date: September 5, 2019
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Kengo HORIKOSHI, Seiji OKAMOTO, Asuka MATSUSHITA, Mitsuteru YOSHIDA, Fukutaro HAMAOKA, Yoshiaki YAMADA, Yoshiaki KISAKA
  • Patent number: 10389452
    Abstract: A coherent optical reception device includes a local oscillation laser that supplies laser light, a coherent optical reception front-end unit that receives a multi-level modulated optical signal, demodulates the optical signal on the basis of the laser light, and converts a demodulated optical signal into an electrical analog signal, an analog-to-digital converter that converts the analog signal into a digital signal, a compensation unit that compensates for an influence of dispersion due to a wavelength or a polarized wave of the optical signal and recovers a carrier phase of the digital signal, a constellation distortion compensation unit that compensates for constellation distortion of the multi-level modulation included in the digital signal in which an influence of dispersion is compensated for by the compensation unit, and an error correction decoding unit that performs error correction of the digital signal in which the constellation distortion is compensated for.
    Type: Grant
    Filed: October 17, 2016
    Date of Patent: August 20, 2019
    Assignees: NIPPON TELEGRAPH AND TELEPHONE CORPORATION, NTT Electronics Corporation
    Inventors: Kengo Horikoshi, Mitsuteru Yoshida, Seiji Okamoto, Eiichi Hosoya, Etsushi Yamazaki, Yasuharu Onuma, Tomohiro Takamuku, Naoki Miura, Sadayuki Yasuda
  • Patent number: 10243664
    Abstract: An optical modulator driver circuit (1) includes an amplifier (50, Q10, Q11, R10-R13), and a current amount adjustment circuit (51) capable of adjusting a current amount of the amplifier (50) in accordance with a desired operation mode. The current amount adjustment circuit (51) includes at least two current sources (IS10) that are individually ON/OFF-controllable in accordance with a binary control signal representing the desired operation mode.
    Type: Grant
    Filed: May 9, 2014
    Date of Patent: March 26, 2019
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Munehiko Nagatani, Hideyuki Nosaka, Toshihiro Itoh, Koichi Murata, Hiroyuki Fukuyama, Takashi Saida, Shin Kamei, Hiroshi Yamazaki, Nobuhiro Kikuchi, Hiroshi Koizumi, Masafumi Nogawa, Hiroaki Katsurai, Hiroyuki Uzawa, Tomoyoshi Kataoka, Naoki Fujiwara, Hiroto Kawakami, Kengo Horikoshi, Yves Bouvier, Mikio Yoneyama, Shigeki Aisawa, Masahiro Suzuki
  • Publication number: 20190013876
    Abstract: A coherent optical reception device includes a local oscillation laser that supplies laser light, a coherent optical reception front-end unit that receives a multi-level modulated optical signal, demodulates the optical signal on the basis of the laser light, and converts a demodulated optical signal into an electrical analog signal, an analog-to-digital converter that converts the analog signal into a digital signal, a compensation unit that compensates for an influence of dispersion due to a wavelength or a polarized wave of the optical signal and recovers a carrier phase of the digital signal, a constellation distortion compensation unit that compensates for constellation distortion of the multi-level modulation included in the digital signal in which an influence of dispersion is compensated for by the compensation unit, and an error correction decoding unit that performs error correction of the digital signal in which the constellation distortion is compensated for.
    Type: Application
    Filed: October 17, 2016
    Publication date: January 10, 2019
    Applicants: NIPPON TELEGRAPH AND TELEPHONE CORPORATION, NTT Electronics Corporation
    Inventors: Kengo HORIKOSHI, Mitsuteru YOSHIDA, Seiji OKAMOTO, Eiichi HOSOYA, Etsushi YAMAZAKI, Yasuharu ONUMA, Tomohiro TAKAMUKU, Naoki MIURA, Sadayuki YASUDA
  • Patent number: 10128818
    Abstract: A parallel transfer rate converter inputs first parallel data with number of samples being S1 pieces in synchronism with a first clock, and outputs second parallel data with number of samples being S2=S1×(m/p) pieces (p is an integer equal to or larger than 1) in synchronism with a second clock having a frequency which is p/m times of a frequency of the first clock. A convolution operation device inputs the second parallel data in synchronism with the second clock, generates third parallel data with number of samples being S3=S2×(n/m) pieces (S3 is an integer equal to or larger than 1) by executing a convolution operation with a coefficient indicating a transmission characteristic to the second parallel data, and outputs the third parallel data in synchronism with the second clock.
    Type: Grant
    Filed: January 16, 2017
    Date of Patent: November 13, 2018
    Assignees: NTT ELECTRONICS CORPORATION, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Yasuharu Onuma, Etsushi Yamazaki, Kazuhito Takei, Osamu Ishida, Kengo Horikoshi, Mitsuteru Yoshida, Yoshiaki Kisaka, Masahito Tomizawa
  • Publication number: 20180252614
    Abstract: A Fourier-transformer performs Fourier transform on a filter coefficient output from an adaptive equalizer which comprises a finite impulse response filter of N taps (N represents an integer of 2 or more) in a time direction. An eigenvalue sum calculator integrates a frequency-differentiation result of the Fourier-transformed filter coefficient and a complex conjugate of the Fourier-transformed filter coefficient to calculate a matrix, and calculates a sum of two eigenvalues of the matrix. A proportionality factor calculator calculates a proportionality factor for frequency from the sum of the two eigenvalues.
    Type: Application
    Filed: October 4, 2016
    Publication date: September 6, 2018
    Inventors: Etsushi YAMAZAKI, Tomohiro TAKAMUKU, Yuki YOSHIDA, Mitsuteru YOSHIDA, Koki SHIBAHARA, Kengo HORIKOSHI, Yoshiaki KISAKA
  • Patent number: 10038507
    Abstract: An increase in circuit scale is suppressed and a phase variation caused in a transmission path or the like is compensated for.
    Type: Grant
    Filed: February 13, 2014
    Date of Patent: July 31, 2018
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Mitsuteru Yoshida, Etsushi Yamazaki, Seiji Okamoto, Hiroyuki Uzawa, Kengo Horikoshi, Koichi Ishihara, Takayuki Kobayashi, Yoshiaki Kisaka, Masahito Tomizawa, Naoki Fujiwara, Tomoyoshi Kataoka, Kazushige Yonenaga
  • Publication number: 20180175830
    Abstract: A parallel transfer rate converter inputs first parallel data with number of samples being S1 pieces in synchronism with a first clock, and outputs second parallel data with number of samples being S2=S1×(m/p) pieces (p is an integer equal to or larger than 1) in synchronism with a second clock having a frequency which is p/m times of a frequency of the first clock. A convolution operation device inputs the second parallel data in synchronism with the second clock, generates third parallel data with number of samples being S3=S2×(n/m) pieces (S3 is an integer equal to or larger than 1) by executing a convolution operation with a coefficient indicating a transmission characteristic to the second parallel data, and outputs the third parallel data in synchronism with the second clock.
    Type: Application
    Filed: January 16, 2017
    Publication date: June 21, 2018
    Inventors: Yasuharu ONUMA, Etsushi YAMAZAKI, Kazuhito TAKEI, Osamu ISHIDA, Kengo HORIKOSHI, Mitsuteru YOSHIDA, Yoshiaki KISAKA, Masahito TOMIZAWA
  • Patent number: 9667350
    Abstract: The optical receiving device with phase compensation apparatus uses coherent opto-electric conversion and is designed for receiving phase- or quadrature-amplitude-modulated optical signals. The phase compensation apparatus includes following elements: a carrier-phase estimation unit that estimates carrier phase errors in a received symbol string; a gain adjustment unit that adjusts weighting of each symbols in phase error evaluation performed in the carrier-phase adjustment unit; a phase-cycle-slip reduction unit with a phase-cycle-slip detector using statistical processing performed on the output symbols from the carrier-phase estimation unit; and a phase compensation circuit that compensates carrier phase errors of the received signal using an output from the carrier phase estimation unit.
    Type: Grant
    Filed: January 24, 2014
    Date of Patent: May 30, 2017
    Assignee: Nippon Telegraph And Telephone Corporation
    Inventors: Kengo Horikoshi, Kohki Shibahara, Etsushi Yamazaki, Mitsuteru Yoshida, Koichi Ishihara, Takayuki Kobayashi, Yoshiaki Kisaka, Takuya Ohara, Masahito Tomizawa, Tomoyoshi Kataoka
  • Patent number: 9621299
    Abstract: The estimation of an amount of chromatic dispersion using a training signal sequence is possible. A transmission method includes: a training signal sequence generation step of generating, as training signal sequences, a plurality of signal sequences having power concentrated in a plurality of frequency bands, the power concentrated at different frequency bands; a training signal sequence selection step of selecting at least one training signal sequence from among the plurality of training signal sequences generated in the training signal sequence generation step, a signal multiplexing step of generating a signal sequence obtained by time-division multiplexing the training signal sequence selected in the training signal sequence selection step with a transmission data sequence, and an electrical-to-optical conversion step of transmitting the signal sequence generated in the signal multiplexing step as an optical signal.
    Type: Grant
    Filed: January 15, 2014
    Date of Patent: April 11, 2017
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Koichi Ishihara, Masato Mizoguchi, Tomoki Murakami, Tomoyoshi Kataoka, Yoshiaki Kisaka, Tadao Nakagawa, Etsushi Yamazaki, Seiji Okamoto, Kengo Horikoshi, Masahito Tomizawa, Riichi Kudo
  • Publication number: 20160087727
    Abstract: An optical modulator driver circuit (1) includes an amplifier (50, Q10, Q11, R10-R13), and a current amount adjustment circuit (51) capable of adjusting a current amount of the amplifier (50) in accordance with a desired operation mode. The current amount adjustment circuit (51) includes at least two current sources (IS10) that are individually ON/OFF-controllable in accordance with a binary control signal representing the desired operation mode.
    Type: Application
    Filed: May 9, 2014
    Publication date: March 24, 2016
    Inventors: Munehiko Nagatani, Hideyuki Nosaka, Toshihiro Itoh, Koichi Murata, Hiroyuki Fukuyama, Takashi Saida, Shin Kamei, Hiroshi Yamazaki, Nobuhiro Kikuchi, Hiroshi Koizumi, Masafumi Nogawa, Hiroaki Katsurai, Hiroyuki Uzawa, Tomoyoshi Kataoka, Naoki Fujiwara, Hiroto Kawakami, Kengo Horikoshi, Yves Bouvier, Mikio Yoneyama, Shigeki Aisawa, Masahiro Suzuki