Polarization Patents (Class 398/65)
  • Patent number: 10396899
    Abstract: Systems and methods for constellation shaping of M-QAM modulation formats in optical transport networks may receive binary data to be transmitted as an optical signal and partition symbols of an M-QAM constellation in the complex plane into two non-overlapping subsets of symbols, The systems and methods may include assigning respective probabilities to each symbol in the first subset of symbols dependent on a target probability distribution for the first subset, mapping at least a portion of the received binary data to the symbols in the first subset, including generating a respective codeword for each symbol in the first subset, in a first symbol period, providing data representing the respective codewords mapped to the symbols in the first subset to an optical modulator for transmission, and refraining from providing any data representing codewords mapped to the symbols in the second subset to the optical modulator until a second symbol period.
    Type: Grant
    Filed: August 21, 2018
    Date of Patent: August 27, 2019
    Assignee: Fujitsu Limited
    Inventors: Inwoong Kim, Olga I. Vassilieva, Paparao Palacharla, Tadashi Ikeuchi
  • Patent number: 10367598
    Abstract: A device (100) for processing a signal, the device comprising a polarization module (102) configured to receive a multi-wavelength optical input signal (Si) comprising a plurality of wavelengths, and for each wavelength. The polarization module is configured to convert a component of each wavelength having a first polarization mode into a converted component having a second, different, polarization mode. The device further comprises a processing module (104,106,114,128) configured to combine the converted component of each wavelength with a direct component of each wavelength received with said second polarization mode. The processing module is configured to generate a multi-wavelength optical output signal (So) solely having said second polarization mode.
    Type: Grant
    Filed: September 25, 2015
    Date of Patent: July 30, 2019
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Francesco Testa, Marco Romagnoli, Vito Sorianello
  • Patent number: 10361779
    Abstract: In the optical transmission system to transmit optical signals using a plurality of adjacent paths, it is difficult to detect a delay difference between a plurality of paths and chromatic dispersion with a high degree of accuracy due to a crosstalk; therefore, a method for detecting optical signal information according to an exemplary aspect of the present invention includes generating a plurality of data signal sequences corresponding to a plurality of paths multiplexed spatially, each of the plurality of data signal sequences obtained by inserting periodically a training signal with a plurality of frequency components in a data signal, in the plurality of data signal sequences, the training signals respectively included in the data signal sequences to be propagated through adjacent paths at least having different frequency components from each other at the same timing, each of a plurality of the training signals included in one of the data signal sequences having the plurality of frequency components whose
    Type: Grant
    Filed: March 17, 2016
    Date of Patent: July 23, 2019
    Assignee: NEC CORPORATION
    Inventors: Manabu Arikawa, Emmanuel Le Taillandier De Gabory, Toshiharu Ito
  • Patent number: 10355452
    Abstract: An optical module includes a light source; a demultiplexer configured to demultiplex a light into a transmission light and a local light; an optical modulator; an excitation light source; an optical waveguide substrate that includes: a polarization beam splitter configured to split a reception light into an X-polarized component and a Y-polarized component, a beam splitter, a pair of optical hybrid circuits configured to cause the X-polarized component and the Y-polarized component to interfere with the local light split by the beam splitter, a pair of local light waveguides configured to couple the beam splitter and the pair of optical hybrid circuits, a pair of reception light waveguides configured to couple the polarization beam splitter and the pair of optical hybrid circuits, wherein the pair of local light waveguides and the transmission light waveguide are doped with a rare-earth ion that amplifies a light when the excitation light is introduced.
    Type: Grant
    Filed: July 15, 2018
    Date of Patent: July 16, 2019
    Assignee: FUJITSU LIMITED
    Inventor: Miki Onaka
  • Patent number: 10345192
    Abstract: Various embodiments relate to a method including: coupling one or more optical spatial pilot signals into a first end of optical fiber, wherein the optical fiber is a multimode optical fiber; Reflecting and modifying each mode of the optical pilot signals at a second end of the optical fiber; receiving a reflected portion of the one or more optical spatial pilot signals at the first end of the of the optical fiber in response to the reflected portion having propagated through the optical fiber in both directions; processing the reflected spatial pilot to determine components of one of a round-trip transfer matrix of the optical fiber and a single-direction transfer matrix of the optical fiber.
    Type: Grant
    Filed: October 24, 2017
    Date of Patent: July 9, 2019
    Assignee: NOKIA OF AMERICA CORPORATION
    Inventors: Haoshuo Chen, Nicolas K. Fontaine, Peter Winzer, Roland Ryf, David Neilson
  • Patent number: 10313050
    Abstract: A phase estimation method and apparatus for a polarization multiplexing system, where the method includes performing, by a receive end, state of polarization (SOP) rotation on a received first SOP signal and second SOP signal according to an angle of previous SOP rotation, extracting a pilot using adaptive filtering, and performing carrier phase estimation according to the extracted pilot. This prevents a noise signal from being extracted and can make a carrier phase estimation result more accurate.
    Type: Grant
    Filed: December 22, 2017
    Date of Patent: June 4, 2019
    Assignee: HUAWEI TECHNOLOGIES CO., LTD.
    Inventor: Yuanda Huang
  • Patent number: 10277328
    Abstract: A signal processing device processes an electric field information signal indicating a polarization multiplexed optical signal in which different modulation formats are used. A first optical signal transmitted in a first polarization component and a second optical signal transmitted in a second polarization component are multiplexed in the polarization multiplexed optical signal. The signal processing device includes a generator and a compensation circuit. The generator selects the first polarization component or the second polarization component based on modulation formats of the first and second optical signals, and generates a compensation value for compensating for an electric field information signal of a selected polarization component based on the electric field information signal of the selected polarization component. The compensation circuit compensates for electric field information signals of the first and second polarization components using the compensation value generated by the generator.
    Type: Grant
    Filed: June 29, 2017
    Date of Patent: April 30, 2019
    Assignee: FUJITSU LIMITED
    Inventors: Tomofumi Oyama, Hisao Nakashima, Yoshitaka Nomura, Takeshi Hoshida, Takahito Tanimura
  • Patent number: 10222624
    Abstract: Provided is a multi-channel optical module device. The optical module device includes: a light source unit configured to include a plurality of laser diodes that are capable of wavelength modulation according to current; a beam splitter unit configured to include a plurality of beam splitters that have different reflectivity and transmissivity and reflect or transmit light output from each laser diode of the light source unit to output them in a first direction or a second direction; and an optical coupler configured to couple and output the light from the beam splitter unit. Center wavelengths of the laser diodes of the light source unit are different from each other, and the number of output channels varies according to the number of laser diodes.
    Type: Grant
    Filed: April 20, 2016
    Date of Patent: March 5, 2019
    Assignee: ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE
    Inventors: Jeong Eun Kim, Hyun Seo Kang, Keo-Sik Kim, Ji Hyoung Ryu, Hyoungjun Park, Young Soon Heo
  • Patent number: 10203458
    Abstract: An optical module and a method of assembling the optical module are disclosed. The optical module comprises a laser unit, a modulator unit, and a detector unit mounted on respective thermo-electric coolers (TECs). The modulator unit, which is arranged on an optical axis of the first output port from which a modulated beam is output, modulates the continuous wave (CW) beam output from the laser unit. On the other hand, the laser unit and the detector unit are arranged on another optical axis of the second output port from which another CW beam is output. The method of assembling the optical module first aligns one of the first combination of the laser unit and the modulator unit with the first output port and the second combination of the laser unit and the detector unit, and then aligns another of the first combination and the second combination.
    Type: Grant
    Filed: April 26, 2017
    Date of Patent: February 12, 2019
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Kazuhiro Yamaji, Yasushi Fujimura, Toru Watanabe, Yasuyuki Yamauchi, Tomoya Saeki, Munetaka Kurokawa
  • Patent number: 10191233
    Abstract: A mirror device for use in an optical subassembly is disclosed that includes at least one surface with a visible indicator to allow a technician to differentiate a highly-reflective surface from relatively less reflective (e.g., un-coated) surfaces. The mirror device may be formed using known approaches, such as through the deposition of a metallic material on to a surface of the mirror device followed by one or more optional coating layers. Before, or after, forming the highly-reflective surface, a visual indicator may be introduced on to a surface of the mirror device that is opposite the highly-reflective surface. The visual indicator may comprise, for example, random scratches/scoring etched from a wire brush or tool, paint, epoxy, ink, or any other indicator that allows a technician to visually differentiate the portion of the mirror device having the visual indicator from the highly-reflective portion.
    Type: Grant
    Filed: March 29, 2017
    Date of Patent: January 29, 2019
    Assignee: Applied Optoelectronics, Inc.
    Inventors: Kai-Sheng Lin, I-Lung Ho, Hsiu-Che Wang
  • Patent number: 10171187
    Abstract: A system and a method for testing a high-speed ADC in a DP-QPSK receiver are disclosed. The system includes a simulation module for outputting a data flow and performing signal recovery, an arbitrary waveform generator for receiving the data flow and outputting a high-speed analog signal and a clock signal, a high-speed ADC for converting the high-speed analog signal and the clock signal into a high-speed digital signal, a cache memory circuit for converting the high-speed digital signal into a low-speed digital signal, and a logic analyzer for sending the low-speed digital signal to the simulation module.
    Type: Grant
    Filed: September 13, 2017
    Date of Patent: January 1, 2019
    Assignee: XIAMEN UX HIGH-SPEED IC CO., LTD.
    Inventors: Zhe Chen, Xiang Xiao, Long Zhao, Bao Li, Yuhua Cheng, Quanchuan Gao, Qiuwei Huang
  • Patent number: 10128959
    Abstract: A method and structure for tap centering in a coherent optical receiver device. The center of gravity (CG) of the filter coefficients can be used to evaluate a proper convergence of a time-domain adaptive equalizer. However, the computation of CG in a dual-polarization optical coherent receiver is difficult when a frequency domain (FD) adaptive equalizer is adopted. In this case, the implementation of several inverse fast-Fourier transform (IFFT) stages is required to back time domain impulse response. Here, examples of the present invention estimate CG directly from the FD equalizer taps and compensate for an error of convergence based off of the estimated CG. This estimation method and associated device architecture is able to achieve an excellent tradeoff between accuracy and complexity.
    Type: Grant
    Filed: October 24, 2017
    Date of Patent: November 13, 2018
    Assignee: INPHI CORPORATION
    Inventors: Mario R. Hueda, José Correa, Oscar E. Agazzi
  • Patent number: 10110319
    Abstract: A method and structure for a coherent optical receiver device. Timing recovery (TR) is implemented after channel dispersion (i.e., chromatic dispersion (CD) and polarization mode dispersion (PMD)) compensation blocks. This architecture provides both improves performance and reduces power consumption of the device. Also, a TR loop is provided, enabling computing, by an error evaluation module, a first sampling phase error (SPE) and computing, by a timing phase information (TPI) module coupled to the error evaluation module, a second SPE from a plurality of CD equalizer taps PMD equalizer taps. The first and second SPE are combined into a total phase error (TPE) in a combining module, and the resulting TPE is filtered by a timing recovery (TR) filter coupled to an interpolated timing recovery (ITR) module and the combining module. The ITR module then synchronizes an input signal of the coherent optical receiver according to the TPE.
    Type: Grant
    Filed: October 24, 2017
    Date of Patent: October 23, 2018
    Assignee: INPHI CORPORATION
    Inventors: Mario R. Hueda, Oscar E. Agazzi
  • Patent number: 10044463
    Abstract: An optical transceiving apparatus includes an optical transmitting device performing polarization multiplexing on and transmitting as polarization multiplexed signal light, a first signal light of a predetermined polarization direction and a second signal light of a polarization direction different from the predetermined polarization direction; an optical receiving device receiving the signal light transmitted from the optical transmitting device through an optical transmission path; an acquiring unit acquiring information indicative of magnitude relation of intensity between the first signal light and the second signal light included in the signal light received by the optical receiving device; and a control unit controlling the magnitude relation of intensity between the first signal light and the second signal light included in the signal light output from the optical transmitting device, to be opposite to the magnitude relation indicated by the information acquired by the acquiring unit.
    Type: Grant
    Filed: September 12, 2016
    Date of Patent: August 7, 2018
    Assignee: FUJITSU LIMITED
    Inventors: Noriaki Mizuguchi, Hiroaki Tomofuji
  • Patent number: 10014943
    Abstract: An optical source (10) comprising: a first laser (12) arranged to generate a first optical signal (14) having a first state of polarization and a first optical frequency; a second laser (16) arranged to generate a second optical signal (18, 48, 78) having a second state of polarization, substantially orthogonal to the first state of polarization, and having a second optical frequency, different to the first optical frequency by a preselected frequency difference, ??; a polarization beam coupler (20) arranged to combine the first optical signal and the second optical signal into a composite optical signal comprising both the first optical signal and the second optical signal having said substantially orthogonal states of polarization; and an output (22) arranged to output the composite optical signal (24).
    Type: Grant
    Filed: March 27, 2014
    Date of Patent: July 3, 2018
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Francesco Testa, Antonio D'Errico, Ernesto Ciaramella, Luca Giorgi, Wei-Ping Huang, Marco Presi
  • Patent number: 9979482
    Abstract: An optical source (10) comprising: a first laser (12) arranged to generate a first optical signal (14) having a first state of polarization and a first optical frequency; a second laser (16) arranged to generate a second optical signal (18, 48, 78) having a second state of polarization, substantially orthogonal to the first state of polarization, and having a second optical frequency, different to the first optical frequency by a preselected frequency difference, ??; a polarization beam coupler (20) arranged to combine the first optical signal and the second optical signal into a composite optical signal comprising both the first optical signal and the second optical signal having said substantially orthogonal states of polarization; and an output (22) arranged to output the composite optical signal (24).
    Type: Grant
    Filed: March 27, 2014
    Date of Patent: May 22, 2018
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Francesco Testa, Antonio D'Errico, Ernesto Ciaramella, Luca Giorgi, Wei-Ping Huang, Marco Presi
  • Patent number: 9972964
    Abstract: An optical device may include a laser emitter to generate a first laser beam and a second laser beam with orthogonal polarization states. The optical device may include first and second photodetectors to generate respective first currents based on optical powers of the first and second laser beams. The optical device may include a polarization-based beam splitter to combine the first and second laser beams. The optical device may include a wavelength filter to filter the first and second laser beams based on respective wavelengths of the first and second laser beams. The optical device may include a third photodetector and a fourth photodetector to generate respective second currents based on optical powers of the first and second laser beams after filtration. The wavelengths of the first and second laser beams may be controlled based on the first currents and the second currents.
    Type: Grant
    Filed: April 19, 2016
    Date of Patent: May 15, 2018
    Assignee: Lumentum Operations LLC
    Inventors: Wei Xiong, Michael C. Larson, Zhaoming Li
  • Patent number: 9973279
    Abstract: The present disclosure discloses a method for eliminating nonlinear effects, a transmitter and a receiver. The method includes: setting signals to be transmitted and redundant signals, where the redundant signals are symmetrical to the signals, which are to be transmitted, about Y axis; and after the setting is completed, respectively executing dispersion pre-compensation on the signals to be transmitted and the redundant signals, and executing signal modulation after the dispersion pre-compensation is completed.
    Type: Grant
    Filed: July 24, 2014
    Date of Patent: May 15, 2018
    Assignee: ZTE Corporation
    Inventor: Bailin Shen
  • Patent number: 9912120
    Abstract: A Raman pump laser control apparatus comprises a wavelength division multiplexer, a tap coupler, a photoelectric detector, an analog amplification processing circuit, an analog-to-digital converter, a fast Raman pump control unit, an digital-analog converter, and a Raman pump laser. The fast Raman pump control unit, after having known anticipated output light power of the Raman pump laser, based on a direct relationship between a current anticipated output light power of the Raman pump laser and input digital quantity that is needed by the digital-analog converter, uses a feedforward control mechanism so that actual output light power of the Raman pump laser fastly approximates the anticipated output light power thereof, and then synchronously combines with a feedback control mechanism so that the actual output light power of the Raman pump laser is precisely locked on the anticipated output light power, thereby achieving fast and precise control of the Raman pump laser.
    Type: Grant
    Filed: December 25, 2013
    Date of Patent: March 6, 2018
    Assignee: Accelink Technologies Co., Ltd.
    Inventors: Yanfeng Fu, Yong Luo, Di Zhang, Xuesheng Tang, Kun Qian, Yi Tang, Shenglei Hu, Qianggao Hu
  • Patent number: 9887729
    Abstract: Systems and methods are disclosed for receiving data by radio frequency (RF) mixing to down-convert in-phase and quadrature parts of a photo-detected electrical RF band signal to baseband for data conversion; controlling a mixing phase of a electrical local oscillator (LO) at one or more RF mixing modules; selecting one of the RF sub-bands to be down-converted to baseband after coherent photo-detection; and performing RF sub-band de-multiplexing for ultra-wide band optical digital coherent detection.
    Type: Grant
    Filed: November 6, 2015
    Date of Patent: February 6, 2018
    Assignee: NEC Corporation
    Inventors: Yue-Kai Huang, Shaoliang Zhang
  • Patent number: 9853739
    Abstract: An optical transmitter includes: a mapper that generates an electric field information signal from transmission data; a phase rotation circuit that adds a phase rotation to the electric field information signal; a driver that generates a driving signal from the electric field information signal to which the phase rotation is added; a modulator that generates a modulated optical signal according to the driving signal; and a controller that controls a bias of the modulator according to a change in a carrier frequency of the modulated optical signal corresponding to the phase rotation that is added to the electric field information signal by the phase rotation circuit.
    Type: Grant
    Filed: June 12, 2015
    Date of Patent: December 26, 2017
    Assignee: FUJITSU LIMITED
    Inventors: Hisao Nakashima, Takeshi Hoshida, Yuichi Akiyama
  • Patent number: 9829638
    Abstract: An optical multiplexer and methods of making and calibrating the same are disclosed. A method of aligning components in a multichannel optical/optoelectronic transmitter includes passively fixing a plurality of light emitters in place on a substrate; adjusting positions of a first lens passing light from a first light emitter and an optical signal transmission medium receiving the light from the first light emitter until a far field spot of the light from the first light emitter is at or near an end of the transmission medium; fixing one or more optical subassemblies on the substrate; and adjusting positions of the optical subassembly(ies) to align light from the remaining light emitters with the far field spot. Some embodiments include multiple optical subassemblies, each including a lens and a filter. Other embodiments include one optical subassembly including a mirror and a beam combiner.
    Type: Grant
    Filed: June 7, 2017
    Date of Patent: November 28, 2017
    Assignee: Source Photonics, Inc.
    Inventors: Moshe Amit, Mark Heimbuch
  • Patent number: 9686013
    Abstract: A system for communication over a fiber link is disclosed. The system comprises a transmitter to transmit an information signal that comprises an information spectrum, and to transmit two spectrally inverted copies of the information spectrum over the predefined length of the fiber link, the two spectrally inverted copies corresponding to a first spectrum with a first center wavelength and to a second spectrum with a second center wavelength, the second spectrum being inverted relative to the first spectrum and the second center wavelength being different from the first center wavelength, and a receiver to receive the first spectrum and the second spectrum, and to estimate a phase rotation of the second spectrum relative to the first spectrum by comparing a first phase measured from the first spectrum with a second phase measured from the second spectrum.
    Type: Grant
    Filed: December 21, 2012
    Date of Patent: June 20, 2017
    Assignee: TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
    Inventors: Bengt-Erik Olsson, Arne Alping
  • Patent number: 9674591
    Abstract: Methods and apparatus for asymmetric distribution of mixed content via a network. Current optical fiber-based access network technologies are multiplexed onto the same fiber for delivery via a common Optical Distribution Network (ODN). Various embodiments of the present disclosure are directed to combining (using optical multiplexing and power splitting) two or more optical user-technologies onto a single Passive Optical Network (PON) while maintaining an independent serving group size and operational independence for each of the combined user-technologies. The disclosed methods and apparatus allow the so-called “outside plant” architecture (i.e., the fiber optic infrastructure from the headend to the customer premises) to be independent of the user-technologies and network architecture that are provided via the outside plant.
    Type: Grant
    Filed: June 8, 2015
    Date of Patent: June 6, 2017
    Assignee: TIME WARNER CABLE ENTERPRISES LLC
    Inventors: Kevin A. Noll, David J. Musser, Paul D. Brooks, Peter H. Wolff
  • Patent number: 9654249
    Abstract: A method of wavelength conversion without polarization tracking is provided. A system is also provided that converts an input signal into an output signal of a different wavelength that contains all of the amplitude, phase, and polarization information of the original signal. The method includes separating, using a polarization-diversity optical mixer, an input optical signal of a first wavelength into a plurality of electrical signals containing amplitudes and phases while maintaining the polarization information of the input signal, converting each of the amplitudes and phases into individual photo-currents using a photo-diode, converting each of the output photo-currents into voltages using an amplifier, modulating the multitude of voltages to a second wavelength using a modulator, where the separated electrical signals are up-converted to generate an output optical signal that maintains the same amplitude, phase, and polarization information as was contained in the input signal.
    Type: Grant
    Filed: September 4, 2015
    Date of Patent: May 16, 2017
    Assignee: NEC Corporation
    Inventors: Yue-Kai Huang, Shaoliang Zhang, Fatih Yaman
  • Patent number: 9559785
    Abstract: Provided is a frequency error estimating apparatus used for a coherent optical receiver, which determines an amplitude of a baseband digital electrical signal converted from a received light signal modulated with a phase and amplitude shift keying, determines, with respect to each determined amplitude, a modulated phase component of the baseband digital electrical signal based on phase noise estimation values and frequency error estimation values of N previous symbols (N is a positive integer), and calculates a frequency error based on an inter-symbol phase difference of a signal obtained by cancelling the modulated phase component from the baseband digital electrical signal.
    Type: Grant
    Filed: January 30, 2014
    Date of Patent: January 31, 2017
    Assignee: FUJITSU LIMITED
    Inventor: Hisao Nakashima
  • Patent number: 9235003
    Abstract: Provided is a waveguide-type polarization beam splitter in which deterioration of a polarization extinction ratio due to temperature change and wavelength change is suppressed. A groove is formed to extend across a pair of optical waveguide arms and two quarter wave plates are provided in the groove to extend respectively across the arms. Polarization axes of the quarter wave plates are orthogonal to each other. A first optical coupler which gives a phase difference of 0° or 180° between coupled or split light beams and a second optical coupler which gives a phase difference of 90° or ?90° between coupled or split light beams are used in combination.
    Type: Grant
    Filed: January 25, 2012
    Date of Patent: January 12, 2016
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Takashi Saida, Yusuke Nasu, Takayuki Mizuno, Ryoichi Kasahara
  • Patent number: 9231727
    Abstract: A polarization multiplexed receiver includes a polarization separator and optical mixing, detecting and analog-to-digital components. The polarization separator receives polarization multiplexed optical signals containing a first data stream and a second data stream, and operate upon the polarization multiplexed optical signals to separate, in an optical domain, the first data stream and the second data stream to generate a first optical output having the first data stream and a second optical output having the second data stream. The optical mixing, detecting and analog-to-digital converting components receive the first and second optical outputs from the polarization separator, extract, in a digital domain, the first data stream from the first optical output of the polarization separator, and extract, in the digital domain, the second data stream from the second optical output of the polarization separator.
    Type: Grant
    Filed: August 30, 2013
    Date of Patent: January 5, 2016
    Assignee: Verizon Patent and Licensing Inc.
    Inventors: Tiejun J. Xia, Glenn A. Wellbrock
  • Patent number: 9178642
    Abstract: This disclosure is directed to optical-to-electrical receiver and transceiver integrated circuits that can be used to send and receive multiple optical signal data streams using at least one optical bus. In one aspect, a fan-in integrated circuit of a node includes an arbiter/multiplexer, and at least one receiver. Each receiver is electronically connected to the arbiter/multiplexer. Each receiver receives at least one optical signal over an optical broadcast bus and converts the optical signals into a data stream encoded in electronic signals. The arbiter/multiplexer selects one receiver at a time to send an electronic signal to the arbiter/multiplexer and outputs the electronic signal to the node for processing.
    Type: Grant
    Filed: October 27, 2010
    Date of Patent: November 3, 2015
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Moray McLaren, Nathann Lorenzo Binkert, David A. Warren, Michael Renne Ty Tan
  • 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: 9093816
    Abstract: An optical transmission apparatus includes an optical amplifier configured to amplify a wavelength-division multiplexed signal light using an amplifying medium doped with a rare earth ion, a first optical transmitter configured to output a wavelength of a dual-polarization-multiplexed signal to a short wavelength side of an amplification band of the optical amplifier, a second optical transmitter configured to output a wavelength of a non polarization-multiplexed signal to a long wavelength side of the amplification band of the optical amplifier, and an optical multiplexer configured to input a wavelength-division multiplexed signal to the optical amplifier, the wavelength-division multiplexed signal comprising the non polarization-multiplexed signal and the dual-polarization-multiplexed signal.
    Type: Grant
    Filed: June 24, 2011
    Date of Patent: July 28, 2015
    Assignee: FUJITSU LIMITED
    Inventors: Norifumi Shukunami, Tatsuya Tsuzuki
  • Patent number: 9071381
    Abstract: The present invention discloses a system for signalling within optical or combined optical/electronic networks wherein a first transmission node executes polarization multiplexing on transmitted traffic, and at one or more intermediate nodes one or more of the following processes are carried out on the sent traffic: demultiplexing by polarization and/or polarization and/or SOP-alignment. Further a method for packet handling within optical packet switched networks where, at a first transmission node carries out polarization demultiplexing of transmitted traffic, and at one or a number of intermediate nodes carries out one or more of the following processes on the transmitted traffic; demultiplexing by polarization, and/or polarization and/or SOP-alignment. Said separation into states of polarization is used in separation of QoS-classes.
    Type: Grant
    Filed: October 26, 2011
    Date of Patent: June 30, 2015
    Assignee: TransPacket AS
    Inventor: Steinar Bjornstad
  • Patent number: 9048955
    Abstract: A tunable dispersion compensation device includes a plurality of tunable dispersion compensators coupled in series, a controller configured to control an amount of chromatic dispersion to be set in each of the plurality of tunable dispersion compensators, and a table including a correspondence relationship between an amount of chromatic dispersion and a wavelength band, for each of the plurality of tunable dispersion compensators, wherein the controller decides an amount of chromatic dispersion to be set in each of the plurality of tunable dispersion compensators, based on a total amount of chromatic dispersion desired for the plurality of tunable dispersion compensators and the correspondence relationship included in the table so that a difference between bandwidths of a first tunable dispersion compensator having the widest wavelength band and a second tunable dispersion compensator having the narrowest wavelength band, among the plurality of tunable dispersion compensators, is within a given range.
    Type: Grant
    Filed: June 5, 2012
    Date of Patent: June 2, 2015
    Assignee: FUJITSU LIMITED
    Inventor: Toshihiro Ohtani
  • Patent number: 9042724
    Abstract: A WDM optical signal is transmitted through a tunable optical filter and is polarization-nulled to find optical signal to noise ratio of individual WDM channels. The polarization nulling can be performed using a heuristic multipoint extrema search method, such as Nelder-Mead method. A plurality of checkpoints can be included in the search to verify the progress and to improve the overall robustness of a real-time polarization nulling.
    Type: Grant
    Filed: December 2, 2013
    Date of Patent: May 26, 2015
    Assignee: JDSU Deutschland GmbH
    Inventor: Axel Flettner
  • Publication number: 20150139649
    Abstract: It is provided a polarization multiplexing optical transceiver including a polarization multiplexing optical transceiver, a polarization multiplexing optical receiver, a transmission side polarization state control unit and a reception side polarization state control unit. The polarization multiplexing optical receiver includes: a polarization demultiplexing unit; a plurality of information signal reconstruction units configured to receive the reconstructed polarization component on the transmission side as an input, and reconstruct and extract information signals; and an information signal coupling unit configured to one of couple and select the information signals output by the plurality of information signal reconstruction units and output the resultant under control of the reception side polarization state control unit.
    Type: Application
    Filed: November 17, 2014
    Publication date: May 21, 2015
    Inventor: Nobuhiko KIKUCHI
  • Publication number: 20150139648
    Abstract: A method and a device for data processing in an optical communication network are provided, wherein in an energy saving mode of a polarization multiplexing system data signals are transmitted or received via one polarization plane; and wherein components of the transmitter or receiver of the other polarization plane are at least partially operated in a reduced power mode. Furthermore, a communication system is suggested comprising said device.
    Type: Application
    Filed: July 10, 2013
    Publication date: May 21, 2015
    Inventors: Arne Striegler, Olaf Adamczyk, Rainer Clemens
  • Patent number: 9036992
    Abstract: Methods and systems for decoding a signal include compensating for impairments in a received signal using at least carrier phase estimation, where residual phase error remains after compensation; calculating symbol log-likelihood ratios (LLRs) for symbols in the compensated signal using Monte Carlo integration; demapping the symbols in the compensated signal using the symbol LLRs and extrinsic information from signal decoding to produce one or more estimated codewords; and decoding each estimated codeword with a decoder that generates a decoded codeword and extrinsic information.
    Type: Grant
    Filed: May 28, 2013
    Date of Patent: May 19, 2015
    Assignee: NEC Laboratories America, Inc.
    Inventors: Ivan B. Djordjevic, Ting Wang
  • Publication number: 20150131996
    Abstract: An optical receiver includes: an optical brancher configured to branch polarization multiplexed light to a first polarization multiplexed light and a second polarization multiplexed light, the polarization multiplexed light in which a pilot signal is superimposed on at least one of a first polarization and a second polarization; an optical fiber configured to transmit the first polarization multiplexed light; a first polarization rotator configured to control a first polarization state of the first polarization multiplexed light output from the optical fiber; a first polarization separator configured to separate the second polarization multiplexed light into a third polarization and a fourth polarization; and a controller configured to control the first polarization rotator based on one of a first pilot signal included in the third polarization and a second pilot signal included in the fourth polarization.
    Type: Application
    Filed: September 24, 2014
    Publication date: May 14, 2015
    Inventor: Futoshi IZUMI
  • Publication number: 20150125150
    Abstract: An optical receiver, includes: a signal processor to perform digital signal processing on a polarization demultiplexed signal obtained by demultiplexing a polarization multiplexed signal corresponding to a reception signal, the signal processor includes: an adaptive equalization circuit to compensate for the polarization demultiplexed signal by control of a filter coefficient; a first frequency offset estimation circuit to receive a first polarization demultiplexed signal diverged at a preceding stage and estimate a first frequency offset; a second frequency offset estimation circuit to receive a second polarization demultiplexed signal diverged at a succeeding stage and estimate a second frequency offset; and a decision circuit to decide whether the filter coefficient is correct based on a first difference between the first frequency offset and the second frequency offset and output, when deciding that the filter coefficient is incorrect, a first trigger for re-calculation of the filter coefficient.
    Type: Application
    Filed: October 6, 2014
    Publication date: May 7, 2015
    Applicant: FUJITSU LIMITED
    Inventors: Kiichi Sugitani, Kazunari Shiota, Eri Katayama
  • Patent number: 9025960
    Abstract: A method implemented by a middlebox comprising registering a customer premises equipment (CPE) in the middlebox, wherein the CPE is coupled to the middlebox via an electrical line, and facilitating registration of the CPE in a central office (CO) equipment coupled to the middlebox.
    Type: Grant
    Filed: March 7, 2013
    Date of Patent: May 5, 2015
    Assignee: Futurewei Technologies, Inc.
    Inventors: Liming Fang, Jim Chen, Li Zhang
  • Patent number: 9025651
    Abstract: Methods, systems, and devices are described for equalizing data from an optical signal. Samples are filtered with at least one filter to compensate for polarization mode dispersion in an optical path. The filtered samples may be used to determine errors based on a difference between a radius of a recovered symbol and a target radius. A parameter may be assigned to one or more of the errors and properties of the at least one filter may be updated based on the assigned parameters. The parameter may be assigned from a small set of parameters based on at least one threshold value. Outputs generated from the filtered samples may also be assigned a parameter from a different set of parameters. The parameter assigned to the output may be used to update the particular set of taps of the at least one filter from which the output was generated.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: May 5, 2015
    Assignee: ViaSat, Inc.
    Inventors: Sameep Dave, Fan Mo
  • Patent number: 9025954
    Abstract: An apparatus comprising a processor configured to obtain one or more plant conditions regarding at least one of a plurality of customer premises equipment (CPEs) remotely coupled to the apparatus via electrical lines, and divide the plurality of coupled CPEs into a number of profile groups based on the one or more plant conditions, wherein each profile group comprises at least one CPE and supports one or more modulation orders.
    Type: Grant
    Filed: March 7, 2013
    Date of Patent: May 5, 2015
    Assignee: Futurewei Technologies, Inc.
    Inventors: Liming Fang, Jim Chen, Li Zhang
  • Publication number: 20150110490
    Abstract: In a receiver, a reception front end receives a polarization-scrambled polarization multiplexed optical signal, polarization-separates the received polarization multiplexed optical signal, and converts each signal into quantized signals. A digital signal processor samples the quantized signals, demodulates the signals by using a polarization separation digital signal processing algorithm, and outputs demodulated signals. When phase and amplitude variations of the demodulated signals are greater than a predetermined value, a control circuit causes the digital signal processor to interrupt processing using the polarization separation digital signal processing algorithm, changes an initial value of a filter coefficient, and then causes the digital signal processor to start the processing using the polarization separation digital signal processing algorithm.
    Type: Application
    Filed: March 1, 2013
    Publication date: April 23, 2015
    Applicant: NEC Corporation
    Inventor: Kouichi Suzuki
  • Patent number: 9008512
    Abstract: An Optical Access Network, a Optical Network Unit (ONU) and various methods for exchanging information are provided.
    Type: Grant
    Filed: June 22, 2011
    Date of Patent: April 14, 2015
    Assignees: Technion Research and Development Foundation Ltd., Yissum Research Development Company of the Hebrew University of Jerusalem Ltd
    Inventors: Moshe Nazarathy, Amos Agmon, Dan M. Marom
  • Patent number: 9002148
    Abstract: A fiber network is monitored in order to detect physical intrusion. The state of polarization of an optical fiber is monitored. A fiber tap is determined to have occurred if the state of polarization of the fiber changes beyond a predetermined amount found to be associated with all types of fiber taps. Alternately, it may be determined that a fiber tap has occurred if the state of polarization changes beyond a second predetermined amount and in a predetermined direction. Monitoring of the state of polarization occurs before and after a time period chosen to be less than a time during which the state of polarization of the optical fiber is expected to drift. This step eliminates false positives due to natural fiber PMD drift.
    Type: Grant
    Filed: March 4, 2013
    Date of Patent: April 7, 2015
    Assignee: RPX Clearing House LLC
    Inventor: Bruce Schofield
  • Patent number: 8995831
    Abstract: A method for processing optical signals includes performing frequency mixing, photoelectric detection, analog/digital conversion, and dispersion compensation on received input optical signals. First-path polarization multiplexing optical signals and second-path polarization multiplexing optical signals. An initialization update process is performed on filter coefficients. Polarization compensation is performed on the first-path polarization multiplexing optical signals and the second-path polarization multiplexing optical signals by using the filter coefficients on which the initialization update is performed to obtain initialized x-path optical signals and initialized y-path optical signals. Preset x-path training sequences and y-path training sequences are synchronized by using the initialized x-path optical signals and the initialized y-path optical signals. If a synchronization result indicates that polarization cross occurs, the polarization cross is rectified.
    Type: Grant
    Filed: October 30, 2012
    Date of Patent: March 31, 2015
    Assignee: Huawei Technologies Co., Ltd.
    Inventors: Liangchuan Li, Ling Liu
  • Patent number: 8995834
    Abstract: An apparatus, e.g. an optical receiver, includes an optical front end and an equalizer. The front end is configured for receiving an optical signal bearing first and second symbols on respective first and second polarization channels. The equalizer is configured to 1) select a first cost function if the first symbol has greater energy than the second symbol, 2) select a second different cost function if the second symbol has a greater energy than the first symbol, and 3) based on the selected cost function, update coefficients of an adaptive filter configured to demultiplex and equalize the first and second polarization channels.
    Type: Grant
    Filed: December 22, 2011
    Date of Patent: March 31, 2015
    Assignee: Alcatel Lucent
    Inventors: Brian Krongold, Timo Pfau, Noriaki Kaneda
  • Patent number: 8995835
    Abstract: The embodiments provide an inverse channel apparatus and transmitter, receiver and system containing the apparatus; wherein the inverse channel apparatus comprises: an inverse nonlinear calculating unit configured to perform nonlinear additive calculation and nonlinear multiplicative calculation on input signals, so as to obtain signals containing nonlinear damage of the input signals on at least one polarization state; and an inverse linear calculating unit configured to calculate signals containing nonlinear damage and linear damage of the input signals on at least one polarization state according to the signals containing nonlinear damage of the input signals on at least one polarization state and a linear function of a channel.
    Type: Grant
    Filed: March 5, 2013
    Date of Patent: March 31, 2015
    Assignee: Fujitsu Limited
    Inventors: Weizhen Yan, Zhenning Tao
  • Publication number: 20150086204
    Abstract: An optical transport system configured to transmit information using two or more modulated optical carriers spaced at spectral intervals that are smaller than the baud rate. An example optical receiver in the optical transport system includes a signal equalizer configured to implement frequency-diversity multiple-input/multiple-output signal processing directed at canceling the effects of inter-carrier interference caused by the spectral overlap between adjacent modulated optical carriers to enable the optical receiver to recover individual data streams encoded onto the different modulated optical carriers at the corresponding optical transmitter(s). Some embodiments of the optical transport system may advantageously be capable of achieving a higher spectral efficiency than the spectral efficiency supported by the optical orthogonal-frequency-division-multiplexing transmission format.
    Type: Application
    Filed: September 20, 2013
    Publication date: March 26, 2015
    Applicant: ALCATEL-LUCENT USA INC.
    Inventor: Noriaki Kaneda
  • Publication number: 20150078749
    Abstract: A planar lightwave circuit includes a substrate in which a groove being formed, the groove dividing the substrate into a first area and a second area; a first filter, a second filter, and a third filter intruded into the groove; as are formed in the first area, a first and a second waveguides formed to guide signal light and local oscillation light; a third and a fourth waveguides formed to guide signal light and local oscillation light; a first 90-degree optical hybrid; as are formed in the second area, a fifth and sixth waveguides formed to guide signal light and local oscillation light; and a second 90-degree optical hybrid.
    Type: Application
    Filed: February 18, 2013
    Publication date: March 19, 2015
    Applicant: NEC CORPORATION
    Inventor: Hiroyuki Yamazaki