Patents by Inventor Sun Hyok Chang

Sun Hyok Chang 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).

  • Patent number: 10904043
    Abstract: An optical transmission method for processing a signal based on direct detection includes setting, by an equalizer, an adaptive equalization coefficient by performing an equalization process during a training symbol field section in a frame of a received signal, performing, by a channel estimator, channel estimation to perform an equalization process of a soft output maximum likelihood sequence equalizer (MLSE) during the training symbol field section, driving the soft output MLSE, and compensating for, by the soft output MLSE, distortion of the received signal during a data symbol field section in the frame on the basis of the adaptive equalization coefficient and an estimated result value of a channel, and recovering, by an error corrector which allows soft-decision processing to be performed, the received signal by performing error correction on the received signal in which the distortion is compensated for.
    Type: Grant
    Filed: May 14, 2020
    Date of Patent: January 26, 2021
    Assignee: ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE
    Inventors: Hun Sik Kang, Sang Rok Moon, Seung Woo Lee, In Ki Hwang, Sun Hyok Chang
  • Publication number: 20200366536
    Abstract: An optical transmission method for processing a signal based on direct detection includes setting, by an equalizer, an adaptive equalization coefficient by performing an equalization process during a training symbol field section in a frame of a received signal, performing, by a channel estimator, channel estimation to perform an equalization process of a soft output maximum likelihood sequence equalizer (MLSE) during the training symbol field section, driving the soft output MLSE, and compensating for, by the soft output MLSE, distortion of the received signal during a data symbol field section in the frame on the basis of the adaptive equalization coefficient and an estimated result value of a channel, and recovering, by an error corrector which allows soft-decision processing to be performed, the received signal by performing error correction on the received signal in which the distortion is compensated for.
    Type: Application
    Filed: May 14, 2020
    Publication date: November 19, 2020
    Inventors: Hun Sik KANG, Sang Rok MOON, Seung Woo LEE, In Ki HWANG, Sun Hyok CHANG
  • Publication number: 20200292759
    Abstract: An optical connection apparatus includes a position fixing portion configured to fix optical circuits each having a different end portion, while interposing a connection member that is optically imprintable between the optical circuits, and an optical-imprinting portion configured to emit light to the connection member to form a three-dimensional (3D) optical waveguide in the connection member that connects the optical circuits to each other.
    Type: Application
    Filed: November 4, 2019
    Publication date: September 17, 2020
    Inventors: Sun Hyok CHANG, Joon Ki LEE
  • Patent number: 10523323
    Abstract: A method and apparatus for compensation of a chromatic dispersion through an optical compensation and an electronical compensation in optical communication. An optical communication method receives an optical signal, estimates a first transmission length based on a null component included in a frequency spectrum of the optical signal, optically compensates for a chromatic dispersion of the optical signal based on the first transmission length, estimates a second transmission length based on a null component included in a frequency spectrum of the compensated optical signal, and electronically compensates for a residual chromatic dispersion of the compensated optical signal based on the second transmission length.
    Type: Grant
    Filed: December 3, 2018
    Date of Patent: December 31, 2019
    Assignee: ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE
    Inventors: Hun Sik Kang, Sang Rok Moon, Seung-Woo Lee, Sun Hyok Chang, In Ki Hwang
  • Patent number: 10523333
    Abstract: An optical signal transmission apparatus generates a multi-level optical signal from a multi-level electric signal. The optical signal transmission apparatus detects, based on a supervisory signal generated from an optical signal, an electric-to-optical (E/O) conversion characteristic of an E/O converter configured to convert an electric signal into an optical signal. For example, when the E/O converter generates a multi-level optical signal from a multi-level electric signal based on a bias signal, the optical signal transmission apparatus determines a correspondence relationship between the bias signal and the optical signal. The optical signal transmission apparatus adjusts a use range of intensities of the bias signal based on the determined correspondence relationship so that the E/O converter may linearly operate.
    Type: Grant
    Filed: June 29, 2018
    Date of Patent: December 31, 2019
    Assignee: ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE
    Inventors: Jie Hyun Lee, Sun Hyok Chang, Joon Young Huh, Sae-Kyoung Kang, Joon Ki Lee
  • Publication number: 20190319708
    Abstract: A method and apparatus for compensation of a chromatic dispersion through an optical compensation and an electronical compensation in optical communication. An optical communication method receives an optical signal, estimates a first transmission length based on a null component included in a frequency spectrum of the optical signal, optically compensates for a chromatic dispersion of the optical signal based on the first transmission length, estimates a second transmission length based on a null component included in a frequency spectrum of the compensated optical signal, and electronically compensates for a residual chromatic dispersion of the compensated optical signal based on the second transmission length.
    Type: Application
    Filed: December 3, 2018
    Publication date: October 17, 2019
    Inventors: Hun Sik KANG, Sang Rok MOON, Seung-Woo LEE, Sun Hyok CHANG, In Ki HWANG
  • Publication number: 20190165867
    Abstract: An optical receiver and a method of controlling the optical receiver. The method may include setting, by a controller, a dispersion value of a dispersion compensator to compensate for a dispersion of an optical signal received through an optical fiber, compensating, by the dispersion compensator, for the dispersion of the optical signal based on the set dispersion value, performing, by the controller, an error correction with respect to the optical signal of which the dispersion is compensated and verifying a number of bit errors, and resetting, by the controller, the dispersion value of the dispersion compensator based on the verified number of bit errors.
    Type: Application
    Filed: June 21, 2018
    Publication date: May 30, 2019
    Inventors: Sun Hyok CHANG, Hun Sik KANG, Joon Ki LEE, Jie Hyun LEE
  • Publication number: 20190158188
    Abstract: An optical signal transmission apparatus generates a multi-level optical signal from a multi-level electric signal. The optical signal transmission apparatus detects, based on a supervisory signal generated from an optical signal, an electric-to-optical (E/O) conversion characteristic of an E/O converter configured to convert an electric signal into an optical signal. For example, when the E/O converter generates a multi-level optical signal from a multi-level electric signal based on a bias signal, the optical signal transmission apparatus determines a correspondence relationship between the bias signal and the optical signal. The optical signal transmission apparatus adjusts a use range of intensities of the bias signal based on the determined correspondence relationship so that the E/O converter may linearly operate.
    Type: Application
    Filed: June 29, 2018
    Publication date: May 23, 2019
    Inventors: Jie Hyun LEE, Sun Hyok CHANG, Joon Young HUH, Sae-Kyoung KANG, Joon Ki LEE
  • Patent number: 9787401
    Abstract: A Mode Division Multiplexed Passive Optical Network (MDM-PON) apparatus includes: a non-mode selective multiplexer which includes a first end where three or more single-mode optical fibers are spaced apart from each other by a predetermined distance, and a second end where cores of the three or more single-mode optical fibers are tapered such that a gap between the three or more single-mode optical fibers is narrower than the predetermined distance while the three or more single-mode optical fibers are spaced apart from each other by an equal distance; an optical line terminal (OLT) which is connected to the second end through a few-mode fiber, and transmits a downstream optical signal; and three or more optical network units (ONUs) which is connected to the first end through the three or more single-mode optical fibers, and transmits upstream optical signals.
    Type: Grant
    Filed: July 25, 2016
    Date of Patent: October 10, 2017
    Assignee: ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE
    Inventors: Sun Hyok Chang, Kwang Joon Kim, Hyun Jae Lee, Chan Gyo Han
  • Publication number: 20170070293
    Abstract: A Mode Division Multiplexed Passive Optical Network (MDM-PON) apparatus includes: a non-mode selective multiplexer which includes a first end where three or more single-mode optical fibers are spaced apart from each other by a predetermined distance, and a second end where cores of the three or more single-mode optical fibers are tapered such that a gap between the three or more single-mode optical fibers is narrower than the predetermined distance while the three or more single-mode optical fibers are spaced apart from each other by an equal distance; an optical line terminal (OLT) which is connected to the second end through a few-mode fiber, and transmits a downstream optical signal; and three or more optical network units (ONUs) which is connected to the first end through the three or more single-mode optical fibers, and transmits upstream optical signals.
    Type: Application
    Filed: July 25, 2016
    Publication date: March 9, 2017
    Inventors: Sun Hyok CHANG, Kwang Joon KIM, Hyun Jae LEE, Chan Gyo HAN
  • Publication number: 20160282560
    Abstract: An optical demultiplexing apparatus and method for multi-carrier distribution are provided. The optical demultiplexing apparatus may include a demultiplexer and a carrier distributor. The optical demultiplexing apparatus and method allow efficient demultiplexing of a multi-carrier light source by using a single demultiplexer even when a carrier spacing of the light source varies.
    Type: Application
    Filed: March 25, 2016
    Publication date: September 29, 2016
    Inventors: Joon Young HUH, Sun Hyok CHANG, Hwan Seok CHUNG
  • Patent number: 9274354
    Abstract: A polarization control device in accordance with an exemplary embodiment of the present invention may include a first polarization converter for converting a polarization angle of an input optical signal in response to first control voltages, a second polarization converter for converting a polarization angle of an input optical signal in response to second control voltages, and a third polarization converter for converting an optical signal received from the first polarization converter or the second polarization converter into a first output optical signal having a linear polarization state and outputting the first output optical signal.
    Type: Grant
    Filed: November 26, 2013
    Date of Patent: March 1, 2016
    Assignee: ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE
    Inventors: Sun Hyok Chang, Hwan Seok Chung
  • Patent number: 9264171
    Abstract: An optical transmission apparatus includes: a transmission light source configured to generate single-mode light of a specific wavelength; a power coupler configured to split the light generated by the transmission light source into a plurality of light sections; at least one modulator configured to modulate an electrical signal carrying different data into at least one optical signal using the light section from the power coupler; and a mode multiplexer configured to convert the modulated optical signal into a different mode, and to transmit the mode-converted optical signal to a fiber.
    Type: Grant
    Filed: April 10, 2014
    Date of Patent: February 16, 2016
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Sun-Hyok Chang, Hwan-Seok Chung
  • Patent number: 9240667
    Abstract: An optical pumping apparatus for few-mode fiber amplification is provided. The optical pumping apparatus includes an optical pump source configured to generate an optical pump; an optical power divider configured to divide an optical power of the optical pump from the optical pump source so as to output several optical pumps with uniformly distributed optical power; and a modal multiplexer configured to receive the optical pumps from the optical power divider through a plurality of single-mode fibers, multiplex the received optical pumps, apply a multiplexed optical pump to each mode of a few-mode fiber (FMF) amplifier, and adjust a gain difference among modes, wherein the FMF amplifier obtains a gain by amplifying an optical signal with the optical pump.
    Type: Grant
    Filed: June 18, 2014
    Date of Patent: January 19, 2016
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Sun-Hyok Chang, Hwan-Seok Chung
  • Publication number: 20150372755
    Abstract: An optical transmitting apparatus based on multicarrier differential phase shift keying. The optical transmitting may include a multicarrier generator to output two or more optical signals, each of which has a different wavelength; two or more optical modulators to receive the two or more optical signals, respectively, which have been output from the multicarrier generator, wherein each of the two or more optical modulators modulates phases of the two or more received optical signals by electrical signals that are applied in pairs.
    Type: Application
    Filed: June 17, 2015
    Publication date: December 24, 2015
    Inventors: Hwan Seok CHUNG, Sun Hyok CHANG
  • Patent number: 9191121
    Abstract: An optical transmitter including an optical modulator comprising a first modulator and a second modulator connected in parallel to each other in the form of a Mach-Zehnder interferometer, and a phase shifter connected to the second modulator in series, a high-speed generator configured to generate a single carrier signal or multi-carrier signals and apply the generated single carrier signal or multi-carrier signals to the optical modulator, and an output stabilizer configured to stabilize a final output optical signal of the optical modulator by controlling a bias of each of the first modulator, the second modulator and the phase shifter.
    Type: Grant
    Filed: November 18, 2013
    Date of Patent: November 17, 2015
    Assignee: ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE
    Inventors: Hwan-Seok Chung, Sun-Hyok Chang
  • Patent number: 8995843
    Abstract: Disclosed is an optical signal transmitting apparatus including: an optical carrier generator configured to generate a plurality of optical carriers and outputs the optical carriers to optical modulators corresponding to the optical carriers, respectively; a plurality of optical modulators configured to modulate the optical carriers, respectively, according to an input signal; and an optical combiner configured to couple a plurality of optical signals from the plurality of optical modulators.
    Type: Grant
    Filed: September 11, 2012
    Date of Patent: March 31, 2015
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Hwan Seok Chung, Sun Hyok Chang
  • Publication number: 20150030325
    Abstract: An optical transmission apparatus includes: a transmission light source configured to generate single-mode light of a specific wavelength; a power coupler configured to split the light generated by the transmission light source into a plurality of light sections; at least one modulator configured to modulate an electrical signal carrying different data into at least one optical signal using the light section from the power coupler; and a mode multiplexer configured to convert the modulated optical signal into a different mode, and to transmit the mode-converted optical signal to a fiber.
    Type: Application
    Filed: April 10, 2014
    Publication date: January 29, 2015
    Applicant: Electronics and Telecommunications Research Institute
    Inventors: Sun-Hyok CHANG, Hwan-Seok CHUNG
  • Publication number: 20150015939
    Abstract: An optical pumping apparatus for few-mode fiber amplification is provided. The optical pumping apparatus includes an optical pump source configured to generate an optical pump; an optical power divider configured to divide an optical power of the optical pump from the optical pump source so as to output several optical pumps with uniformly distributed optical power; and a modal multiplexer configured to receive the optical pumps from the optical power divider through a plurality of single-mode fibers, multiplex the received optical pumps, apply a multiplexed optical pump to each mode of a few-mode fiber (FMF) amplifier, and adjust a gain difference among modes, wherein the FMF amplifier obtains a gain by amplifying an optical signal with the optical pump.
    Type: Application
    Filed: June 18, 2014
    Publication date: January 15, 2015
    Inventors: Sun-Hyok CHANG, Hwan-Seok CHUNG
  • Publication number: 20140294401
    Abstract: An optical transmitter including an optical modulator comprising a first modulator and a second modulator connected in parallel to each other in the form of a Mach-Zehnder interferometer, and a phase shifter connected to the second modulator in series, a high-speed generator configured to generate a single carrier signal or multi-carrier signals and apply the generated single carrier signal or multi-carrier signals to the optical modulator, and an output stabilizer configured to stabilize a final output optical signal of the optical modulator by controlling a bias of each of the first modulator, the second modulator and the phase shifter.
    Type: Application
    Filed: November 18, 2013
    Publication date: October 2, 2014
    Applicant: Electronics and Telecommunications Research Institute
    Inventors: Hwan-Seok CHUNG, Sun-Hyok CHANG