Patents by Inventor Inwoong Kim

Inwoong Kim 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: 20170346593
    Abstract: Methods and systems are provided for determining a shortest minimum regeneration path in an optical network. The method includes creating a virtual node at a source node, the source node communicatively coupled to a destination node through a plurality of nodes and links. The method includes traversing the virtual nodes, wherein traversing the virtual nodes comprises selecting an unvisited virtual node at a node; identifying a candidate virtual node from the unvisited virtual node; determining whether the candidate virtual node exceeds a maximum permitted weight; determining whether the candidate virtual node violates a shortest minimum regeneration path condition; and creating the new virtual node from the candidate virtual node if the candidate virtual node does not exceed the maximum permitted weight and if the candidate virtual node does not violate the shortest minimum regeneration path condition.
    Type: Application
    Filed: May 31, 2016
    Publication date: November 30, 2017
    Inventors: Inwoong Kim, Xi Wang, Qiong Zhang, Paparao Palacharla, Tadashi Ikeuchi
  • Publication number: 20170288905
    Abstract: In one or more embodiments, one or more systems of a physical optical network that may implement and/or manage a virtual optical network (VON) that interconnects multiple data centers. Virtual nodes based the multiple data centers to be interconnected may be determined, and each of the virtual nodes may be mapped to at least two physical nodes of the physical optical network. Virtual links for pairs of the virtual nodes may be determined, and each virtual link may be mapped to at least one optical network connection of the physical optical network. At least one of a physical node impairment and an optical network connection impairment that is associated with a first physical node implementing a first virtual node may be detected, and the first virtual node may be implemented via a second physical node.
    Type: Application
    Filed: February 2, 2017
    Publication date: October 5, 2017
    Inventors: Xi Wang, Paparao Palacharla, Qiong Zhang, Inwoong Kim, Tadashi Ikeuchi
  • Patent number: 9768878
    Abstract: Methods and systems for superchannel power pre-emphasis may adjust power levels of selected subcarriers of the superchannel. The power pre-emphasis may be performed at a transmission stage using a laser source, a variable optical attenuator, or a wavelength selective switch. The power pre-emphasis may be performed in-line at a reconfigurable optical add-drop multiplexer node. The power pre-emphasis may be performed using feedback control based on a receiver output. The power pre-emphasis may be performed using feedforward control based on optical path computations.
    Type: Grant
    Filed: May 18, 2015
    Date of Patent: September 19, 2017
    Assignee: Fujitsu Limited
    Inventors: Olga Vassilieva, Inwoong Kim, Motoyoshi Sekiya
  • Publication number: 20170214488
    Abstract: Methods and systems for transmitting superchannels with mixed baud rate subcarriers include modifying baud rates for certain subcarriers in order to improve or equalize optical signal-to-noise ratio penalties incurred during transmission. Additionally frequency shifts may be applied to individual subcarriers. The baud rate modification and frequency shifts may be symmetrical for spectral positions of subcarriers within the superchannel.
    Type: Application
    Filed: January 27, 2016
    Publication date: July 27, 2017
    Inventors: Olga Vassilieva, Inwoong Kim, Motoyoshi Sekiya
  • Patent number: 9712249
    Abstract: Methods and systems for superchannel subcarrier monitoring using amplitude modulated (AM) tones include modulating an optical subcarrier of a superchannel with a first frequency that is chosen to be substantially smaller than a baud rate for data modulated onto the optical subcarrier. Certain pairs of subcarriers in the superchannel may be modulated with AM tones having a common frequency with complementary phase for power equalization. Then, downstream detection and monitoring of the optical subcarrier may be performed based on demodulation of the first frequency. Each optical subcarrier in the superchannel may be modulated using a respectively unique combination of AM tone and phase.
    Type: Grant
    Filed: July 2, 2015
    Date of Patent: July 18, 2017
    Assignee: Fujitsu Limited
    Inventors: Inwoong Kim, Olga Vassilieva, Motoyoshi Sekiya
  • Patent number: 9698912
    Abstract: Methods and systems for superchannel subcarrier monitoring using frequency modulated (FM) tones includes frequency modulating an optical subcarrier of a superchannel with a first frequency that is unique to the optical subcarrier and is chosen to be smaller than an optical transmission frequency for carrier data modulated onto the optical subcarrier. Then, downstream detection and monitoring of the optical subcarrier may be performed based on demodulation of the first frequency. Each optical subcarrier in the superchannel may be modulated using a respectively unique FM tone.
    Type: Grant
    Filed: July 2, 2015
    Date of Patent: July 4, 2017
    Assignee: Fujitsu Limited
    Inventors: Olga Vassilieva, Inwoong Kim, Motoyoshi Sekiya
  • Patent number: 9673907
    Abstract: Methods and systems for constellation shaping of modulation formats in optical communication systems may involve enabling an optical transport network to activate/deactivate constellation shaping on a per channel basis for a given optical path using universal programmable transceivers. Then, constellation shaping may be activated to increase the reach of optical channels by improving signal-to-noise ratio over the optical path.
    Type: Grant
    Filed: March 29, 2016
    Date of Patent: June 6, 2017
    Assignee: Fujitsu Limited
    Inventors: Olga Vassilieva, Inwoong Kim, Tadashi Ikeuchi
  • Publication number: 20170141871
    Abstract: Methods and systems for amplifying optical signals include generating idler signals for input signals using an optical pump at a first Bragg reflection waveguide (BRW) having second order optical nonlinearity. Phase and amplitude regulation is performed using the output from the first BRW. Optical power monitoring of the input signals may be used for power equalization. The phase-sensitive amplified signal is generated at a second BRW using the optical pump. Optical power monitoring of the input signals may be used for power equalization.
    Type: Application
    Filed: November 18, 2015
    Publication date: May 18, 2017
    Inventors: Jeng-Yuan Yang, Inwoong Kim, Youichi Akasaka, Motoyoshi Sekiya
  • Patent number: 9654223
    Abstract: Methods and systems for superchannel power pre-emphasis based on transmission criteria may determine a guardband used when transmitting multiple superchannels over an optical transport network. The guardband values may depend on various transmission criteria, such as a reach distance for the superchannels and a number of reconfigurable add-drop multiplexer nodes over a given optical path. An amount of power pre-emphasis for each superchannel may then be determined based on the actual guardband values used. Certain values used for superchannel power pre-emphasis based on transmission criteria may be pre-calculated and stored in advance.
    Type: Grant
    Filed: December 8, 2015
    Date of Patent: May 16, 2017
    Assignee: Fujitsu Limited
    Inventors: Olga Vassilieva, Inwoong Kim, Motoyoshi Sekiya
  • Publication number: 20170126353
    Abstract: Methods and systems are provided for wavelength shift elimination during spectral inversion in optical networks. The method includes receiving an input optical signal, and generating a combined optical signal by combining, by Bragg scattering, the input optical signal having an input wavelength with a first pump signal having a first wavelength. The method further includes converting the combined optical signal into an output optical signal, by phase-conjugation, using a second pump signal having a second wavelength. The output optical signal has the same wavelength as the input optical signal.
    Type: Application
    Filed: October 30, 2015
    Publication date: May 4, 2017
    Inventors: Kevin Croussore, Inwoong Kim, Olga I. Vassilieva, Takao Naito
  • Publication number: 20170104847
    Abstract: Systems and methods for performing vertex-centric service function chaining in multi-domain networks are disclosed. A resource orchestration framework of a multi-domain network may include vertices representing physical nodes and edges representing physical links in the network. A sole resource orchestrator (in a centralized system) or multiple resource orchestrators (each associated with a respective domain in a distributed system) may coordinate execution of a common compute function on multiple vertices to identify candidate service function chain solutions to a service function chain request. The request may specify a fixed-ordered chain or a flexible-ordered chain. The compute function may, during each of multiple supersteps, determine whether a partially mapped chain can be extended on a given vertex, send a controller message to a neighbor vertex with which it has a qualified link, or return a completed chain, which may be selected for execution, dependent on applicable policies.
    Type: Application
    Filed: June 7, 2016
    Publication date: April 13, 2017
    Inventors: Qiong Zhang, Paparao Palacharla, Xi Wang, Inwoong Kim, Tadashi Ikeuchi
  • Publication number: 20170104632
    Abstract: Methods and systems enable optimized placement of wavelength shifters in optical networks. The wavelength shifters may include O-E-O regenerators for a single wavelength and all optical wavelength shifters for one or more wavelengths. An auxiliary graph is used to represent various links in a provisioned optical path. By applying cost values to each of the links, different types of optimizations for network resource utilization may be realized.
    Type: Application
    Filed: October 12, 2015
    Publication date: April 13, 2017
    Inventors: Inwoong Kim, Xi Wang, Paparao Palacharla, Tadashi Ikeuchi
  • Patent number: 9614638
    Abstract: Methods and systems for periodic optical filtering to identify tone modulated optical signals may enable relatively rapid scanning of an optical signal to identify individual optical channels. The optical signal having tone modulated optical channels may be scanned over a free spectral range of a periodic optical filter, such as a comb filter, to generate a filtered signal. Then, center optical frequencies for each of the optical channels in the filtered signal may be determined by demodulation and digital signal processing.
    Type: Grant
    Filed: July 2, 2015
    Date of Patent: April 4, 2017
    Assignee: Fujitsu Limited
    Inventors: Inwoong Kim, Olga Vassilieva, Paparao Palacharla, Motoyoshi Sekiya
  • Publication number: 20170085322
    Abstract: Methods and systems enable amplifying optical signals using a Bragg reflection waveguide (BRW) having second order optical nonlinearity to generate an optical pump by injection locking The BRW may also be used for parametric amplification of optical signals using the optical pump. Feedback phase-power control may be performed to maximize output power.
    Type: Application
    Filed: September 23, 2015
    Publication date: March 23, 2017
    Inventors: Inwoong Kim, Youichi Akasaka, Jeng-Yuan Yang, Motoyoshi Sekiya
  • Publication number: 20170005726
    Abstract: Methods and systems for superchannel subcarrier monitoring using amplitude modulated (AM) tones include modulating an optical subcarrier of a superchannel with a first frequency that is chosen to be substantially smaller than a baud rate for data modulated onto the optical subcarrier. Certain pairs of subcarriers in the superchannel may be modulated with AM tones having a common frequency with complementary phase for power equalization. Then, downstream detection and monitoring of the optical subcarrier may be performed based on demodulation of the first frequency. Each optical subcarrier in the superchannel may be modulated using a respectively unique combination of AM tone and phase.
    Type: Application
    Filed: July 2, 2015
    Publication date: January 5, 2017
    Inventors: Inwoong Kim, Olga Vassilieva, Motoyoshi Sekiya
  • Publication number: 20170005747
    Abstract: Methods and systems for periodic optical filtering to identify tone modulated optical signals may enable relatively rapid scanning of an optical signal to identify individual optical channels. The optical signal having tone modulated optical channels may be scanned over a free spectral range of a periodic optical filter, such as a comb filter, to generate a filtered signal. Then, center optical frequencies for each of the optical channels in the filtered signal may be determined by demodulation and digital signal processing.
    Type: Application
    Filed: July 2, 2015
    Publication date: January 5, 2017
    Inventors: Inwoong Kim, Olga Vassilieva, Paparao Palacharla, Motoyoshi Sekiya
  • Publication number: 20170005725
    Abstract: Methods and systems for superchannel subcarrier monitoring using frequency modulated (FM) tones includes frequency modulating an optical subcarrier of a superchannel with a first frequency that is unique to the optical subcarrier and is chosen to be smaller than an optical transmission frequency for carrier data modulated onto the optical subcarrier. Then, downstream detection and monitoring of the optical subcarrier may be performed based on demodulation of the first frequency. Each optical subcarrier in the superchannel may be modulated using a respectively unique FM tone.
    Type: Application
    Filed: July 2, 2015
    Publication date: January 5, 2017
    Inventors: Olga Vassilieva, Inwoong Kim, Motoyoshi Sekiya
  • Patent number: 9515734
    Abstract: In one embodiment, a method for receiving optical signals includes receiving a first set of one or more signals and a second set of one or more signals, determining a block length used to process the first set of signals, and processing the first set of signals using the block length. The first set of signals and the second set of signals are separated by a guard band. The block length is based upon the width of the guard band.
    Type: Grant
    Filed: July 16, 2010
    Date of Patent: December 6, 2016
    Assignee: Fujitsu Limited
    Inventors: Inwoong Kim, Olga I. Vassilieva
  • Publication number: 20160344481
    Abstract: Methods and systems for superchannel power pre-emphasis may adjust power levels of selected subcarriers of the superchannel. The power pre-emphasis may be performed at a transmission stage using a laser source, a variable optical attenuator, or a wavelength selective switch. The power pre-emphasis may be performed in-line at a reconfigurable optical add-drop multiplexer node. The power pre-emphasis may be performed using feedback control based on a receiver output. The power pre-emphasis may be performed using feedforward control based on optical path computations.
    Type: Application
    Filed: May 18, 2015
    Publication date: November 24, 2016
    Inventors: Olga Vassilieva, Inwoong Kim, Motoyoshi Sekiya
  • Patent number: 9485019
    Abstract: Methods and systems for optical channel monitoring of dual polarization optical signals may use a periodic optical filter to scan a free spectral range of the periodic optical filter. The optical signals may further be tone modulated using frequency or amplitude modulation. From a filtered signal, normalized Stokes vector signals may be generated using a polarimeter. The normalized Stokes vector signals may be digitally processed to identify center frequencies and power levels of individual optical subcarriers.
    Type: Grant
    Filed: July 2, 2015
    Date of Patent: November 1, 2016
    Assignee: Fujitsu Limited
    Inventors: Inwoong Kim, Olga Vassilieva, Motoyoshi Sekiya