Patents by Inventor Takaaki Ogata

Takaaki Ogata 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: 20220173808
    Abstract: Aspects of the present disclosure describe systems, methods. and structures in which guided acoustic Brillouin (GAWBS) noise is measured using a homodyne measurement technique and demonstrated using a number of optical fibers, such fibers being commonly used in contemporary optical communications systems. The measurements are made with single spans and determined to be consistent with separate multi-span long-distance measurements. Additionally, a technique for preparing an optical fiber exhibiting superior GAWBS noise characteristics by reducing coherence length of the optical fiber by spinning the fiber at a high rate during the drawing process such that birefringence coherence length is reduced.
    Type: Application
    Filed: December 1, 2021
    Publication date: June 2, 2022
    Applicant: NEC LABORATORIES AMERICA, INC
    Inventors: Fatih YAMAN, Kohei NAKAMURA, Takanori INOUE, Eduardo Mateo RODRIGUEZ, Shinsuke FUJISAWA, Hussam BATSHON, Yoshihisa INADA, Takaaki OGATA
  • Publication number: 20220011195
    Abstract: Aspects of the present disclosure describe a method for estimating mode field distribution in optical fibers from guided acoustic-wave Brillouin scattering wherein light for which the optical mode-field distribution is determined remains in the optical fibers and the distribution is made for light inside the fiber, and not at a fiber/air interface or other perturbation points to the fiber resulting in a more accurate representation of the optical mode-field distribution in the fiber. Since light is always in the fiber during the determination, no complicated fiber preparation steps or procedures are required and the mode-field distribution is determined as an average distribution along the length of the fiber under test.
    Type: Application
    Filed: June 7, 2021
    Publication date: January 13, 2022
    Applicants: NEC LABORATORIES AMERICA, INC, NEC Corporation
    Inventors: Fatih YAMAN, Eduardo Mateo RODRIGUEZ, Shinsuke FUJISAWA, Hussam BATSHON, Kohei NAKAMURA, Takanori INOUE, Yoshihisa INADA, Takaaki OGATA
  • Publication number: 20200403383
    Abstract: Aspects of the present disclosure describe systems, methods and structures for providing semiconductor amplifiers exhibiting a low polarization-dependent gain.
    Type: Application
    Filed: June 17, 2020
    Publication date: December 24, 2020
    Applicant: NEC LABORATORIES AMERICA, INC
    Inventors: Fatih YAMAN, Shinsuke FUJISAWA, Eduardo Mateo RODRIGUEZ, Kohei NAKAMURA, Takanori INOUE, Yoshihisa INADA, Takaaki OGATA
  • Patent number: 10581216
    Abstract: An optical communication substrate includes a plurality of cores to communicate optical signals; a rectangular input delivering a pump laser, and a shaped portion to combine the optical signals and the pump laser into a ring geometry at an output.
    Type: Grant
    Filed: May 3, 2017
    Date of Patent: March 3, 2020
    Assignee: NEC Corporation
    Inventors: Fatih Yaman, Shaoliang Zhang, Eduardo Mateo Rodriquez, Takanori Inoue, Yoshihisa Inada, Takaaki Ogata
  • Patent number: 10401564
    Abstract: Aspects of the present disclosure describe fiber nonlinearity induced transmission penalties are reduced both in fibers with large polarization-mode dispersion, and in coupled-core multicore fibers (CC-MCF). In the case of coupled multi-core fibers, the requirement for modal delay is less.
    Type: Grant
    Filed: October 9, 2018
    Date of Patent: September 3, 2019
    Assignee: NEC CORPORATION
    Inventors: Fatih Yaman, Shaoliang Zhang, Eduardo Mateo Rodriguez, Takanori Inoue, Kohei Nakamura, Yoshihisa Inada, Takaaki Ogata
  • Publication number: 20190107671
    Abstract: Aspects of the present disclosure describe fiber nonlinearity induced transmission penalties are reduced both in fibers with large polarization-mode dispersion, and in coupled-core multicore fibers (CC-MCF). In the case of coupled multi-core fibers, the requirement for modal delay is less.
    Type: Application
    Filed: October 9, 2018
    Publication date: April 11, 2019
    Inventors: Fatih YAMAN, Shaoliang ZHANG, EDUARDO MATEO RODRIGUEZ, TAKANORI INOUE, KOHEI NAKAMURA, YOSHIHISA INADA, TAKAAKI OGATA
  • Publication number: 20180109067
    Abstract: An optical communication substrate includes a plurality of cores to communicate optical signals; a rectangular input delivering a pump laser, and a shaped portion to combine the optical signals and the pump laser into a ring geometry at an output.
    Type: Application
    Filed: May 3, 2017
    Publication date: April 19, 2018
    Inventors: Fatih Yaman, Shaoliang Zhang, Eduardo Mateo Rodriquez, Takanori Inoue, Yoshihisa Inada, Takaaki Ogata
  • Publication number: 20170353247
    Abstract: Methods and systems for communication with a modified constellation are provided. One of the methods includes coding, by a transmitter in the user equipment, an input data stream into a constellation of symbols having at least two neighboring symbols therein which differ by more than one bit and which are separated by a modified Euclidean distance to increase a Gaussian white noise resiliency of the at least two neighboring symbols with respect to remaining symbols, the remaining symbols being separated by the Euclidean distance of exactly one bit. The method further includes modulating, by the transmitter, the symbol stream into a transmission stream.
    Type: Application
    Filed: March 23, 2016
    Publication date: December 7, 2017
    Inventors: Fatih Yaman, Shaoliang Zhang, Eduardo Mateo Rodriquez, Yoshihisa Inada, Takaaki Ogata
  • Patent number: 9819530
    Abstract: Methods and systems for communication with an optimized constellation include coding an input data stream to a symbol stream according to an optimized constellation that has a non-Gray bit mapping and that has neighboring points having more than one bit difference farther apart than neighboring points having one bit difference. The symbol stream is modulated onto a transmission signal and subsequently demodulated at a receiver to produce a received symbol stream. The received symbol stream is decoded to a bitstream according to an optimized constellation that has a non-Gray bit mapping and that has neighboring points having more than one bit difference farther apart than neighboring points having one bit difference.
    Type: Grant
    Filed: March 24, 2016
    Date of Patent: November 14, 2017
    Assignee: NEC Corporation
    Inventors: Fatih Yaman, Shaoliang Zhang, Eduardo Mateo Rodriquez, Yoshihisa Inada, Takaaki Ogata, Takanori Inoue
  • Patent number: 9722700
    Abstract: A wavelength division multiplexing system and method featuring a wavelength monitor that is configured to receive a portion of a combined signal of wavelength division multiplexing channels and determine the wavelengths of each channel or the guardband between each channel in the combined signal. The wavelength monitor determines if there is excess laser drift for each channel in the combined signal. If excess laser drift is determined, feedback is sent to the transmitter for the signal with excess laser drift and the signal is adjusted to produce a target wavelength. The wavelength monitor may utilize optical intradyning in order to monitor the wavelengths of each channel in the combined signal.
    Type: Grant
    Filed: July 23, 2015
    Date of Patent: August 1, 2017
    Assignee: NEC Corporation
    Inventors: Fatih Yaman, Shaoliang Zhang, Ting Wang, Yoshihisa Inada, Takaaki Ogata
  • Publication number: 20160285668
    Abstract: Methods and systems for communication with an optimized constellation include coding an input data stream to a symbol stream according to an optimized constellation that has a non-Gray bit mapping and that has neighboring points having more than one bit difference farther apart than neighboring points having one bit difference. The symbol stream is modulated onto a transmission signal and subsequently demodulated at a receiver to produce a received symbol stream. The received symbol stream is decoded to a bitstream according to an optimized constellation that has a non-Gray bit mapping and that has neighboring points having more than one bit difference farther apart than neighboring points having one bit difference.
    Type: Application
    Filed: March 24, 2016
    Publication date: September 29, 2016
    Inventors: Fatih Yaman, Shaoliang Zhang, Eduardo Mateo Rodriquez, Yoshihisa Inada, Takaaki Ogata, Takanori Inoue
  • Patent number: 9337923
    Abstract: A method includes evaluating an optical signal spectrum for estimated filtering parameters of an optical spectral filtering device for shaping optical signal spectrum, determining a feedback for fine tuning the optical spectral filtering device for nonlinearity tolerance enhancement in the optical transmission system, responsive to received optical signal quality in the optical signal spectrum; and using the feedback to adjust said optical spectral filtering device for predetermined shaping and predetermined fiber nonlinearity tolerance in the optical transmission system.
    Type: Grant
    Filed: October 18, 2012
    Date of Patent: May 10, 2016
    Assignee: NEC Corporation
    Inventors: Lei Xu, Shaoliang Zhang, Fatih Yaman, Ting Wang, Yoshihisa Inada, Takaaki Ogata, Yasuhiro Aoki
  • Patent number: 9337868
    Abstract: At a receiver side, to enhance the performance of concatenated LDPC and TCM coding, an iterative decoding between TCM decoder and LDPC decoder enables improvement in the reliability of received LLRs of each symbol after each iteration. A SOVA output of the TCM is used for LDPC decoding, and then the updated LLRs from LDPC decoder are further looped back to the TCM decoder for the next iteration. In such a manner, the decoding performance could be significantly improved after just several iterations.
    Type: Grant
    Filed: July 21, 2014
    Date of Patent: May 10, 2016
    Assignee: NEC Corporation
    Inventors: Shaoliang Zhang, Fatih Yaman, Yoshihisa Inada, Takaaki Ogata, Takanori Inoue
  • Publication number: 20160028504
    Abstract: A wavelength division multiplexing system and method featuring a wavelength monitor that is configured to receive a portion of a combined signal of wavelength division multiplexing channels and determine the wavelengths of each channel or the guardband between each channel in the combined signal. The wavelength monitor determines if there is excess laser drift for each channel in the combined signal. If excess laser drift is determined, feedback is sent to the transmitter for the signal with excess laser drift and the signal is adjusted to produce a target wavelength. The wavelength monitor may utilize optical intradyning in order to monitor the wavelengths of each channel in the combined signal.
    Type: Application
    Filed: July 23, 2015
    Publication date: January 28, 2016
    Inventors: Fatih Yaman, Shaoliang Zhang, Ting Wang, Yoshihisa Inada, Takaaki Ogata
  • Patent number: 9203519
    Abstract: The invention is directed to a novel computer implemented method for finding a modulation format that has better receiver sensitivity than modulation formats that are currently being used, with a correlated symbol modulation in which neighboring symbols are coded and decoded together to increase receiver sensitivity.
    Type: Grant
    Filed: October 2, 2013
    Date of Patent: December 1, 2015
    Assignees: NEC Laboratories America, Inc., NEC Corporation
    Inventors: Fatih Yaman, Shaoliang Zhang, Ting Wang, Yoshihisa Inada, Takaaki Ogata, Yasuhiro Aoki
  • Patent number: 9130679
    Abstract: Methods and systems for transmission and reception of ternary phase-shift keyed data that include mapping triplets of binary bits to pairs of ternary symbols, such that three bits of data are encoded across two symbols having three-point constellations; modulating the pairs of ternary symbols onto a carrier; and transmitting the modulated carrier across a transmission medium.
    Type: Grant
    Filed: April 2, 2012
    Date of Patent: September 8, 2015
    Assignees: NEC Laboratories America, Inc., NEC Corporation
    Inventors: Ezra Ip, Fatih Yaman, Lei Xu, Ting Wang, Yoshihisa Inada, Takaaki Ogata, Yasuhiro Aoki
  • Patent number: 9077484
    Abstract: Methods, structures and systems for generating different polarization multiplexed signals wherein the drivers of the modulators are generic while a software-controlled manager allows the carrying of any standard 10 G/40 G/100 G data while—at the same time—being adaptively adjustable according to specific link requirements and users' requests in both dispersion-managed and uncompensated links.
    Type: Grant
    Filed: October 4, 2013
    Date of Patent: July 7, 2015
    Assignees: NEC Laboratories America, Inc., NEC Corporation
    Inventors: Shaoliang Zhang, Fatih Yaman, Ting Wang, Yoshihisa Inada, Takaaki Ogata, Yasuhiro Aoki
  • Publication number: 20150026541
    Abstract: At a receiver side, to enhance the performance of concatenated LDPC and TCM coding, an iterative decoding between TCM decoder and LDPC decoder enables improvement in the reliability of received LLRs of each symbol after each iteration. A SOVA output of the TCM is used for LDPC decoding, and then the updated LLRs from LDPC decoder are further looped back to the TCM decoder for the next iteration. In such a manner, the decoding performance could be significantly improved after just several iterations.
    Type: Application
    Filed: July 21, 2014
    Publication date: January 22, 2015
    Inventors: Shaoliang Zhang, Fatih Yaman, Yoshihisa Inada, Takaaki Ogata, Takanori Inoue
  • Patent number: 8917998
    Abstract: A method implemented in a transmission apparatus used in an optical fiber communications system for a polarization switched differential quaternary phase-shift keying (DQPSK) signal is disclosed. The method comprises splitting data into two or more data streams, inputting said two or more data streams to 1-bit DQPSK precoders to perform 1-bit DQPSK precoding, and multiplexing inphase outputs of the 1-bit DQPSK precoders to generate a first output; and multiplexing quadrature outputs of the 1-bit DQPSK precoders to generate a second output. Other methods, apparatuses, and systems also are disclosed.
    Type: Grant
    Filed: October 11, 2012
    Date of Patent: December 23, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Shaoliang Zhang, Lei Xu, Junqiang Hu, Fatih Yaman, Ting Wang, Yoshihisa Inada, Takaaki Ogata, Yasuhiro Aoki
  • Patent number: 8873953
    Abstract: An inventive method for multi-symbol polarization switching for differential detection optical systems includes modulating a laser source by a DQPSK modulator, driving the DQPSK modulator with a data block configured for generating multi-symbol polarization-switched DQPSK differential-encoded signals, and polarizing the multi-symbol polarization-switched DQPSK signals with a polarizing modulator whose modulation speed is based on how often polarization states vary, wherein the data block provides a bits manipulation to provide the multi-symbol polarization switching thereby enabling differential detection for recovering correct original data by a receiver.
    Type: Grant
    Filed: June 14, 2012
    Date of Patent: October 28, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Shaoliang Zhang, Fatih Yaman, Lei Xu, Ting Wang, Yoshihisa Inada, Takaaki Ogata, Yasuhiro Aoki