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).

  • Patent number: 9485554
    Abstract: Methods and systems for using modulation frequencies for optical channel monitoring with periodic optical filtering may allocate modulation frequencies based on bandwidth slices of an optical spectrum. The bandwidth slices may have an equal spectral band that is associated with a respectively unique modulation frequency. An optical carrier aligning with a bandwidth slice may be modulated using the modulation frequency assigned to that bandwidth slice. Additionally, the bandwidth slices may be used to determine a maximum frequency error of an optical carrier when received, such as from frequency drift during transmission.
    Type: Grant
    Filed: July 2, 2015
    Date of Patent: November 1, 2016
    Assignee: Fujitsu Limited
    Inventors: Inwoong Kim, Olga Vassilieva, Paparao Palacharla, Motoyoshi Sekiya
  • Publication number: 20160315712
    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: Application
    Filed: December 8, 2015
    Publication date: October 27, 2016
    Inventors: Olga Vassilieva, Inwoong Kim, Motoyoshi Sekiya
  • Publication number: 20160316283
    Abstract: Methods and systems may estimate nonlinear penalties for optical paths using spectral inversion in optical transport networks. Certain values of nonlinear transfer functions for nonlinear penalty estimation may be pre-calculated for optical paths between given nodes. When an optical path computation for using spectral inversion between a given source node and a given destination node is desired, the pre-calculated values may be concatenated for improved computational efficiency.
    Type: Application
    Filed: February 4, 2016
    Publication date: October 27, 2016
    Inventors: Inwoong Kim, Olga Vassilieva, Paparao Palacharla, Motoyoshi Sekiya
  • Patent number: 9461745
    Abstract: According to an aspect of an embodiment, a method of modeling an optical signal transmission path may include obtaining first transmission characteristics of an optical signal transmission path within an optical network based on a parameter of the optical network and randomly changing states of polarization of an optical signal within the optical signal transmission path. The method may also include obtaining second transmission characteristics of the optical signal transmission path based on the parameter and a first fixed state of polarization of the optical signal. The method may also include correlating the first transmission characteristics with the second transmission characteristics to obtain an effective state of polarization of the optical signal. A simulation of the optical signal transmission path based on the parameter and the effective state of polarization of the optical signal may produce transmission characteristics that may approximate the first transmission characteristics.
    Type: Grant
    Filed: March 22, 2012
    Date of Patent: October 4, 2016
    Assignee: FUJITSU LIMITED
    Inventors: Olga Vassilieva, Inwoong Kim, Motoyoshi Sekiya
  • Patent number: 9444550
    Abstract: Flexible VON provisioning may include calculating a candidate mapping pattern to satisfy a virtual optical network (VON) demand based on virtual-to-physical node mapping choices. A distance-adaptive routing and spectral slot assignment evaluation of the candidate mapping pattern may be performed. When the VON demand is satisfied by the candidate mapping pattern, the candidate mapping pattern may be added to a valid mapping patterns list. A final mapping pattern may be selected from the valid mapping patterns list, the final mapping pattern having one of a lowest slot layer and a smallest overall slot usage on the valid mapping patterns list. Then, network resources may be reserved based on the final mapping pattern selected to service the VON demand.
    Type: Grant
    Filed: June 25, 2014
    Date of Patent: September 13, 2016
    Assignee: Fujitsu Limited
    Inventors: Xi Wang, Qiong Zhang, Inwoong Kim, Paparao Palacharla, Motoyoshi Sekiya
  • Patent number: 9374158
    Abstract: Systems and methods of electronic wavefront correction are disclosed. An example method receiving an optical signal representing a wavefront traveling along a plurality of propagation paths, and electronically correcting distortion in the wavefront. An example apparatus includes an receiver and an electronic wavefront corrector. The receiver is configured to coherently receive an optical signal representing a wavefront traveling along a plurality of propagation paths. The electronic wavefront corrector is configured to correct phase distortion in the wavefront.
    Type: Grant
    Filed: September 26, 2008
    Date of Patent: June 21, 2016
    Assignee: University of Central Florida Research Foundation, Inc.
    Inventors: Guifang Li, Inwoong Kim, Xiaobo Xie
  • Patent number: 9344194
    Abstract: A system includes an optical power meter operable to generate an optical power signal corresponding to the optical power of a received output signal generated by an optical IQ-modulator. The system further includes a processor operable to receive the optical power signal and determine, based on a minimization algorithm and the received optical power signal, a first bias voltage to be applied to a first sub-modulator of the optical IQ-modulator and a second bias voltage to be applied to a second sub-modulator of the optical IQ-modulator. The system may also include a peak power meter operable to generate a peak power signal corresponding to the peak power of the received output signal generated by the optical IQ-modulator, wherein the processor is further operable to determine, based on a minimization algorithm and the received peak power signal, a third bias voltage to be applied to a phase shift component of the optical IQ-modulator.
    Type: Grant
    Filed: February 21, 2013
    Date of Patent: May 17, 2016
    Assignee: Fujitsu Limited
    Inventors: Inwoong Kim, Olga Vassilieva, Paparao Palacharla, Motoyoshi Sekiya
  • Patent number: 9344190
    Abstract: Methods and systems are provided for flexible placement of spectral inverters in an optical network. The method includes identifying a first transmission path coupling a transmitter and a receiver. The first transmission path includes a first node for assignment of a first spectral inverter. The method further includes estimating a first optical signal-to-noise ratio (OSNR) penalty of nonlinear phase noise (NLPN) on the first transmission path with the first spectral inverter assigned to the first node, and based on the first estimated OSNR penalty of NLPN being less than an NLPN penalty threshold, assigning the first spectral inverter to the first node.
    Type: Grant
    Filed: May 14, 2014
    Date of Patent: May 17, 2016
    Assignee: Fujitsu Limited
    Inventors: Inwoong Kim, Olga Vassilieva, Paparao Palacharla, Motoyoshi Sekiya
  • Patent number: 9197323
    Abstract: Methods and systems for asymmetrically compensating degradation of an optical signal-to-noise ratio (OSNR) induced by polarization dependent loss (PDL) in dual-polarization optical system include using an OSNR compensator. The OSNR compensator may separate the dual-polarization components and determine which component has degraded OSNR. The degraded component may be OSNR compensated using a phase-sensitive amplifier and/or a regenerator with a phase-sensitive amplifier.
    Type: Grant
    Filed: June 18, 2013
    Date of Patent: November 24, 2015
    Assignee: Fujitsu Limited
    Inventors: Olga Vassilieva, Inwoong Kim, Jeng-Yuan Yang, Motoyoshi Sekiya
  • Patent number: 9197320
    Abstract: Systems and method for monitoring a dual-polarization signal are disclosed. The systems and methods include adding a first supervisory signal to a first polarization component of the dual-polarization signal to get a first combined signal, adding a second supervisory signal to a second polarization component of the dual-polarization signal to get a second combined signal, and in the electrical domain, performing a polarization scanning technique on the first and second combined signals.
    Type: Grant
    Filed: November 4, 2013
    Date of Patent: November 24, 2015
    Assignee: Fujitsu Limited
    Inventors: Olga Vassilieva, Inwoong Kim, Motoyoshi Sekiya
  • Publication number: 20150333825
    Abstract: Methods and systems are provided for flexible placement of spectral inverters in an optical network. The method includes identifying a first transmission path coupling a transmitter and a receiver. The first transmission path includes a first node for assignment of a first spectral inverter. The method further includes estimating a first optical signal-to-noise ratio (OSNR) penalty of nonlinear phase noise (NLPN) on the first transmission path with the first spectral inverter assigned to the first node, and based on the first estimated OSNR penalty of NLPN being less than an NLPN penalty threshold, assigning the first spectral inverter to the first node.
    Type: Application
    Filed: May 14, 2014
    Publication date: November 19, 2015
    Inventors: Inwoong Kim, Olga Vassilieva, Paparao Palacharla, Motoyoshi Sekiya
  • Publication number: 20150295761
    Abstract: Object-oriented network virtualization may involve creating and operating virtual network objects (VNO) using a software-programmed networking operating system (SPN OS). A VNO may be a complete representation of a virtual network service provided under the SPN OS. A VNO may have a unique identity and properties, along with an internal set of methods for executing functionality encapsulated by the VNO. A VNO may exhibit persistence and autonomous control to enable improved virtual network services.
    Type: Application
    Filed: December 18, 2014
    Publication date: October 15, 2015
    Inventors: Xi Wang, Motoyoshi Sekiya, Paparao Palacharla, Qiong Zhang, Inwoong Kim
  • Patent number: 9112609
    Abstract: Methods and systems for mitigating effects of polarization dependent loss (PDL) in an optical network transmitting a multi-carrier optical signal comprising a plurality of subcarriers may involve assigning and modifying a state of polarization to each subcarrier prior to transmission. An assigned state of polarization for each subcarrier may be modified for the subcarrier in the digital domain and/or the optical domain. Various specific assignment methods may be used, including individual subcarrier assignment, subcarrier set assignment, arbitrary subcarrier group assignment, random assignment, and/or combinations thereof. The assigned states of polarization may be selected based on a resulting minimum PDL-induced peak-to-peak power variation over a sum of the subcarriers for all orientations of a principal axis of PDL.
    Type: Grant
    Filed: June 10, 2013
    Date of Patent: August 18, 2015
    Assignee: Fujitsu Limited
    Inventors: Inwoong Kim, Olga Vassilieva, Paparao Palacharla, Motoyoshi Sekiya
  • Patent number: 9083485
    Abstract: According to an aspect of an embodiment, a method of spectrum defragmentation in an optical network may include assigning an optical signal within an optical network to a first frequency slot that spans a first portion of an optical spectrum of the optical network. The method may also include constructing a frequency slot dependency map based on the assignation of the optical signal to the frequency slot. The method may also include reassigning, as a result of an optical signal departure event, the optical signal to a second frequency slot based on the frequency slot dependency map. The second frequency slot may span a second portion of the optical spectrum of the optical network.
    Type: Grant
    Filed: April 12, 2012
    Date of Patent: July 14, 2015
    Assignee: FUJITSU LIMITED
    Inventors: Xi Wang, Inwoong Kim, Paparao Palacharla, Motoyoshi Sekiya
  • Patent number: 9042730
    Abstract: A method for adjusting an optical signal includes determining a polarization dependent loss (PDL) value associated with the optical signal, determining an angle between the optical signal and one or more axes of PDL, determining an amount of nonlinear phase noise due to PDL and nonlinear effects upon the optical signal based upon the PDL value and the angle, determining a phase rotation based upon the amount of nonlinear phase noise, and applying the phase rotation to the optical signal.
    Type: Grant
    Filed: February 8, 2013
    Date of Patent: May 26, 2015
    Assignee: Fujitsu Limited
    Inventors: Olga Vassilieva, Inwoong Kim, Motoyoshi Sekiya
  • Publication number: 20150131987
    Abstract: Systems and method for monitoring a dual-polarization signal are disclosed. The systems and methods include adding a first supervisory signal to a first polarization component of the dual-polarization signal to get a first combined signal and adding a second supervisory signal to a second polarization component of the dual-polarization signal to get a second combined signal, either in the electrical or optical domain. The supervisory signals are arbitrary, non-complementary, and modulated at a frequency substantially lower than the modulation frequency of the dual-polarization signal. The systems and methods further include analyzing the supervisory signals upon receipt.
    Type: Application
    Filed: November 14, 2013
    Publication date: May 14, 2015
    Applicant: Fujitsu Limited
    Inventors: Jeng-Yuan Yang, Inwoong Kim, Olga Vassilieva, Motoyoshi Sekiya
  • Publication number: 20150125143
    Abstract: Systems and method for monitoring a dual-polarization signal are disclosed. The systems and methods include adding a first supervisory signal to a first polarization component of the dual-polarization signal to get a first combined signal, adding a second supervisory signal to a second polarization component of the dual-polarization signal to get a second combined signal, and in the electrical domain, performing a polarization scanning technique on the first and second combined signals.
    Type: Application
    Filed: November 4, 2013
    Publication date: May 7, 2015
    Applicant: Fujitsu Limited
    Inventors: Olga Vassilieva, Inwoong Kim, Motoyoshi Sekiya
  • Publication number: 20150117856
    Abstract: Systems and methods for monitoring a dual-polarization signal are disclosed. The systems and methods include extracting a portion of the dual-polarization signal, wherein the dual-polarization signal includes multiple supervisory signals, each associated with a polarization component of a main data signal, measuring a power level of the first and second supervisory signals, and determining a power imbalance between the polarization components of the main data signal based at least on the power level.
    Type: Application
    Filed: October 30, 2013
    Publication date: April 30, 2015
    Applicant: Fujitsu Limited
    Inventors: Olga Vassilieva, Inwoong Kim, Jeng-Yuan Yang, Motoyoshi Sekiya
  • Publication number: 20150117857
    Abstract: Systems and method for monitoring a dual-polarization signal are disclosed. The systems and methods include adding a first supervisory signal to a first polarization component of the dual-polarization signal to get a first combined signal and adding a second supervisory signal to a second polarization component of the dual-polarization signal to get a second combined signal, either in the electrical or optical domain. The supervisory signal is arbitrary, non-complementary, and modulated at a amplitude substantially lower than the modulation frequency of the dual-polarization signal. The systems and methods further include analyzing the supervisory signal upon receipt.
    Type: Application
    Filed: October 30, 2013
    Publication date: April 30, 2015
    Applicant: Fujitsu Limited
    Inventors: Olga Vassilieva, Inwoong Kim, Jeng-Yuan Yang, Motoyoshi Sekiya
  • Publication number: 20150104172
    Abstract: Flexible VON provisioning may include calculating a candidate mapping pattern to satisfy a virtual optical network (VON) demand based on virtual-to-physical node mapping choices. A distance-adaptive routing and spectral slot assignment evaluation of the candidate mapping pattern may be performed. When the VON demand is satisfied by the candidate mapping pattern, the candidate mapping pattern may be added to a valid mapping patterns list. A final mapping pattern may be selected from the valid mapping patterns list, the final mapping pattern having one of a lowest slot layer and a smallest overall slot usage on the valid mapping patterns list. Then, network resources may be reserved based on the final mapping pattern selected to service the VON demand.
    Type: Application
    Filed: June 25, 2014
    Publication date: April 16, 2015
    Inventors: Xi Wang, Qiong Zhang, Inwoong Kim, Paparao Palacharla, Motoyoshi Sekiya