Hybrid Modulation Patents (Class 398/185)
  • Patent number: 11509396
    Abstract: Provided is a polarization multiplexing optical transmitting and receiving circuit that compensates for transmission side PDL so as to suppress a reduction in transmission power and makes a branching ratio of light from a light source variable between a transmission side and a receiving side according to a system to be used.
    Type: Grant
    Filed: March 19, 2020
    Date of Patent: November 22, 2022
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Yusuke Nasu, Shogo Yamanaka, Yuichiro Ikuma
  • Patent number: 11411366
    Abstract: A WDM seed beam source for a fiber laser amplifier system that includes a number of master oscillators that generate seed beams at different wavelengths and a spectral multiplexer that multiplexes all of the seed beams onto a single fiber. An EOM modulates the combined seed beams on the single fiber and a spectral demultiplexer then separates the modulated seed beams into their constituent wavelengths on separate fibers before the seed beams are amplified and spectrally combined. The fiber laser amplifier system includes a separate fiber amplifier that amplifies the separated seed beams, an emitter array that directs the amplified beams into free space, beam collimating optics that focuses the uncombined beams, and an SBC grating responsive to the collimated uncombined beams that spatially combines the collimated uncombined beams.
    Type: Grant
    Filed: January 15, 2019
    Date of Patent: August 9, 2022
    Assignee: NORTHROP GRUMMAN SYSTEMS CORPORATION
    Inventors: Gregory D. Goodno, Eric C. Cheung
  • Patent number: 11321562
    Abstract: A conformance testing method including: obtaining a testing symbol pattern in an optical signal; performing equalization compensation on the testing symbol pattern; generating a testing eye pattern; calculating a value of a first parameter based on the testing eye pattern and a noise enhancement coefficient, where the first parameter is used to determine a transmitter dispersion eye pattern closure degree of the optical transmitter; and when the value of the first parameter is less than or equal to a preset threshold, determining that conformance testing on the optical signal succeeds.
    Type: Grant
    Filed: October 23, 2020
    Date of Patent: May 3, 2022
    Assignee: HUAWEI TECHNOLOGIES CO., LTD.
    Inventors: Jianyu Zheng, Shengping Li, Ting Yang
  • Patent number: 11112564
    Abstract: A method of nonblocking optical switching includes guiding a first optical beam from a first input to a first output via a first path through an optical switching fabric. The first path traverses a phase shifter disposed between a pair of cascaded Mach-Zehnder interferometers. The method also includes receiving a second optical beam for a second path intersecting with the first path through the optical switching fabric. The method also includes moving the first optical beam from the first path to a third path connecting the first input to the first output without intersecting the second path. The method also includes shifting a phase of the first optical beam, with the phase shifter, while moving the first optical beam from the first path to the third path to prevent the first optical beam from interfering with the second optical beam.
    Type: Grant
    Filed: March 24, 2020
    Date of Patent: September 7, 2021
    Assignee: Massachusetts Institute of Technology
    Inventors: Gregory R. Steinbrecher, Dirk Robert Englund
  • Patent number: 11108468
    Abstract: An optical transmitter includes a first narrowband signal processing unit, a wideband signal generation unit, and an optical modulator. The first narrowband signal generation unit is configured to input a first signal and a second signal and output first, second, third and fourth narrowband signals. The wideband signal generation unit is configured to multiply the first and second narrowband signals by sinusoidal signals having a phase difference of (?/2), respectively, to shift bands of the first and second narrowband signals, and combine the shifted first and second narrowband signal to generate a first wideband signal. The wideband signal generation unit is configured to multiply the third and fourth narrowband signal by sinusoidal signals having a phase difference of (?/2), respectively, to shift bands of the third and fourth narrowband signals, and combine the shifted third and fourth narrowband signals to generate a second wideband signal.
    Type: Grant
    Filed: August 6, 2018
    Date of Patent: August 31, 2021
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Fukutaro Hamaoka, Masanori Nakamura
  • Patent number: 11075698
    Abstract: The disclosure relates to technology for signal transmission in an optical communication system. An optical transmitter comprises a directly modulated laser (DML) configured to generate a modulated optical signal in response to a modulation signal. The modulated optical signal comprises a first frequency corresponding to a logical one value in the modulation signal and a second frequency corresponding to a logical zero value in the modulation signal. The modulated optical signal has a modulation symbol rate of “R”. The transmitter comprises a controller configured to control the DML to establish a target frequency gap between the first frequency and the second frequency. The transmitter also comprises an optical band pass filter (OBPF) coupled to the DML to receive the modulated optical signal and output a filtered optical signal. The OBPF has a 3-dB bandwidth of less than R.
    Type: Grant
    Filed: August 3, 2020
    Date of Patent: July 27, 2021
    Assignee: Huawei Technologies Co., Ltd.
    Inventors: Xiang Liu, Ning Cheng, Frank Effenberger
  • Patent number: 10637576
    Abstract: A transmitter for an optical free-beam communication system includes two light transmitters for the optical transmission of a data signal using one single-sideband modulation, wherein each light transmitter emits a side of the band modulation so that a light signal arriving at a receiver corresponds to a double-sideband modulation.
    Type: Grant
    Filed: October 28, 2016
    Date of Patent: April 28, 2020
    Assignee: Deutsches Zentrum für Luft-und Raumfahrt e.V.
    Inventors: Ramon Mata Calvo, Dirk Giggenbach, Christian Fuchs, Ahmad Mustafa
  • Patent number: 10509243
    Abstract: An optical IQ modulator with automatic bias control is disclosed. A dither signal is applied to the modulator bias and its signature detected in light tapped from an output of the modulator using a phase sensitive dither detector such as a lock-in amplifier. The detected signal is processed using pre-recorded information defining the direction of the detected signal change relative to a change in the modulator bias, and the bias is adjusted in the direction determined using the information. The IQ phase bias is controlled by dithering I and Q optical signals in quadrature to produce opposite-sign single subband modulation of output light at two different dither frequencies, and detecting an oscillation at a difference frequency using a lock-in detector.
    Type: Grant
    Filed: November 13, 2017
    Date of Patent: December 17, 2019
    Assignee: Elenion Technologies, LLC
    Inventor: Bernd-Harald Horst Jurgen Rohde
  • Patent number: 10505339
    Abstract: An optical transmission system includes a laser module that generates a modulated optical waveform including both amplitude and frequency modulation; and an optical shaping filter that converts at least part of the frequency modulation to additional amplitude modulation. The optical transmission system is tuned by: measuring, based on the amplitude modulation of a filtered waveform output from the optical shaping filter, an average output power of the optical shaping filter; and adjusting a temperature of the laser module to a first temperature at which a target output condition is achieved, including: adjusting the temperature of the laser module to a first target temperature at which the average output power of the filtered waveform satisfies a first output criteria, or adjusting the temperature of the laser module to a second target temperature at which the output power and extinction ratio of the filtered waveform satisfy a second output criteria.
    Type: Grant
    Filed: September 17, 2018
    Date of Patent: December 10, 2019
    Assignee: ADTRAN, Inc.
    Inventors: Daniel M. Joffe, Leif Sandstrom
  • Patent number: 10498458
    Abstract: An optical modulator for generating quadrature amplitude modulation (nQAM) and phase-shift keying (nPSK) signals with tunable modulation efficiency. The modulator includes a controlling circuit for adjusting the modulation efficiency or modulation depth of the modulator by controlling the direct current (DC) bias.
    Type: Grant
    Filed: November 3, 2016
    Date of Patent: December 3, 2019
    Assignee: Futurewei Technologies, Inc.
    Inventors: Xueyan Zheng, Yu Sheng Bai, Xiao Shen, Yangjing Wen
  • Patent number: 10396898
    Abstract: An optical module installed within an optical transmitter apparatus is disclosed. The optical module provides an electrically insulating carrier, a semiconductor element, and a capacitor. The carrier provides a ground pattern and a bias pad. The ground pattern mounts the capacitor and the semiconductor element thereon. The bias pad is electrically isolated from the ground pattern thereby forming a parasitic capacitor against the ground pattern. The optical module further includes at least two bonding wires among a first bonding wire connecting the semiconductor element with the bias pad, a second bonding wire connecting the bias pad with the capacitor, and an additional bonding wire connecting the capacitor with the semiconductor element. The semiconductor element is supplied with a bias current through the at least two bonding wires.
    Type: Grant
    Filed: November 1, 2017
    Date of Patent: August 27, 2019
    Assignee: SUMITOMO ELECTRIC DEVICE INNOVATIONS, INC.
    Inventors: Shuichi Kubota, Masahiro Hirayama
  • Patent number: 10243667
    Abstract: An optical transmitter includes an optical modulator configured to modulate light from a light source; and a processor configured to generate a drive signal that is input into the optical modulator. The processor inserts a bias control signal amplitude-modulated at a low frequency, into an analog signal at fixed intervals, to generate the drive signal.
    Type: Grant
    Filed: April 5, 2018
    Date of Patent: March 26, 2019
    Assignee: FUJITSU OPTICAL COMPONENTS LIMITED
    Inventors: Sukeyuki Iwata, Toshiki Tanaka, Masato Nishihara, Naoki Kuwata
  • Patent number: 9749721
    Abstract: The present invention discloses data receiving and sending methods and apparatuses and a system, and relates to the field of communications technologies. The data receiving method includes: receiving a data carrier; deciding polar radius values of multiple labeled constellation points carried at a pre-determined location in the data carrier, to determine a numerical value indicated by a polar radius value of each labeled constellation point in the multiple labeled constellation points; determining, according to a sequence including numerical values indicated by polar radius values of all the labeled constellation points in the multiple labeled constellation points, a demodulation scheme of a constellation point, other than the multiple labeled constellation points, carried in the data carrier; and demodulating, according to the determined demodulation scheme, the constellation point, other than the multiple labeled constellation points, carried in the data carrier.
    Type: Grant
    Filed: December 7, 2015
    Date of Patent: August 29, 2017
    Assignee: Huawei Technologies Co., Ltd.
    Inventors: Mo Li, Ning Deng, Qingsong Xue, Guowei Gong
  • Patent number: 9722397
    Abstract: A tunable laser includes: a wavelength filter that includes a first ring resonator and a second ring resonator each of which is formed by a waveguide including a silicon waveguide core, and each of which is capable of shifting each of resonance wavelengths that exit periodically and whose intervals are different from each other; and an integrated device that is optically coupled to the wavelength filter, and in which a first semiconductor optical amplifier and a reflector are provided in sequence from a side of the wavelength filter, wherein the resonance wavelengths of the first ring resonator and the second ring resonator are overlapped with each other at one wavelength, and the resonance wavelengths are overlapped with each other also at a plurality of wavelengths other than the one wavelength.
    Type: Grant
    Filed: November 16, 2015
    Date of Patent: August 1, 2017
    Assignee: FUJITSU LIMITED
    Inventors: Kazumasa Takabayashi, Tsuyoshi Yamamoto, Manabu Matsuda
  • Patent number: 9608760
    Abstract: The present invention is an optical terminal device comprising a signal modulator configured to generate a first signal modulated onto a first optical sideband of a first optical wavelength signal and a second signal modulated onto a second sideband of the first optical wavelength signal, the first signal being a different type than the second signal; a receiver configured to receive a third signal modulated onto the first optical sideband of a second optical wavelength signal and a fourth signal modulated onto a second sideband of the second optical wavelength signal, the third signal being a different type than the fourth signal; and a circulator coupled to the signal modulator and the receiver, wherein the circulator is configured to communicate with a node of an integrated network via an optical fiber. A remote node, a communication terminal, and a method of performing integrated network access are also disclosed.
    Type: Grant
    Filed: September 20, 2012
    Date of Patent: March 28, 2017
    Assignee: Nanyang Technological University
    Inventors: Wende Zhong, Quang Thai Pham
  • Patent number: 9461751
    Abstract: A method of transmitting a data signal in an optical communications system. The method includes processing the data signal to generate an analog drive signal, wherein the processing comprises applying a first non-linear operation such that frequency components of the drive signal lay in at least two separated spectral bands. An optical carrier light is modulated using the analog drive signal.
    Type: Grant
    Filed: December 18, 2012
    Date of Patent: October 4, 2016
    Assignee: Ciena Corporation
    Inventors: James Harley, Roger Carroll, Shahab Oveis Gharan, Kim B. Roberts
  • Patent number: 9300402
    Abstract: Dispersion may be managed in an optical network by allowing accumulation of dispersion to at least ten thousand ps/nm, and several tens of thousands of ps/nm in some embodiments. The accumulated dispersion may be returned to zero or near zero at a receiver and/or at one or more branch paths coupled to the transmission path.
    Type: Grant
    Filed: December 14, 2011
    Date of Patent: March 29, 2016
    Assignee: TYCO ELECTRONICS SUBSEA COMMUNICATIONS LLC
    Inventors: William Anderson, Alexei N. Pilipetskii
  • Patent number: 9252889
    Abstract: A method for optical transmission of high speed data and an optical receiver for receiving such high speed data is provided. The method includes transmitting an optical signal having a first logic-high and first logic-low defining a first modulation amplitude that is sub-band modulated with a toggling signal having a first toggling amplitude with a first modulation index, receiving the optical signal with an optical receiver circuit and converting the optical signal to an intermediate electrical signal, IES, having: a second logic-high and a second logic-low defining a second modulation amplitude, and a second toggling amplitude having a second modulation index, providing a decision threshold relative to the IES as a function of the second modulation amplitude, and adjusting the threshold by determining the second toggling amplitude and adjusting the threshold relative to the IES based on proportionality between the second toggling amplitude and the second modulation amplitude.z.
    Type: Grant
    Filed: November 5, 2012
    Date of Patent: February 2, 2016
    Assignee: MELLANOX TECHNOLOGIES DENMARK APS
    Inventor: Steen Bak Christensen
  • Publication number: 20150125160
    Abstract: Methods and apparatus for directly detected optical system based on gapped CAP modulation and DSP Methods for generation and reconstruction of gapped CAP signal are disclosed. An apparatus for direct detection transmission for CAP modulated signal with two unbalanced optical sidebands separated by gaps is disclosed, in which a gapped CAP signal is generated, converted, and passed to an optical filter for unbalanced sidebands generation and wavelength locking before being transmitted over an optical link. Direct detection is performed on the optical signal and passed to gapped matching filters. Channel equalization is performed and the signal information is decoded to binary data.
    Type: Application
    Filed: November 7, 2013
    Publication date: May 7, 2015
    Applicant: Futurewei Technologies, Inc.
    Inventors: Yangjing WEN, Xiao SHEN, Yusheng BAI
  • Publication number: 20150117869
    Abstract: An optical multilevel transmitter includes a semiconductor quadrature optical modulator configured to separately modulate and output in-phase and quadrature electric field components and a semiconductor nonlinear characteristic compensation circuit configured to generate, from in-phase and quadrature drive signals to be inputted to the semiconductor quadrature optical modulator, two signals for correcting each other and to add the two correcting signals to the corresponding drive signals.
    Type: Application
    Filed: October 31, 2014
    Publication date: April 30, 2015
    Inventors: Yuki WAKAYAMA, Nobuhiko KIKUCHI
  • Patent number: 8995844
    Abstract: An optical homodyne communication system and method in which a side carrier is transmitted along with data bands in an optical data signal, and upon reception, the side carrier is boosted, shifted to the center of the data bands, and its polarization state is matched to the polarization state of the respective data bands to compensate for polarization mode dispersion during transmission. By shifting a boosted side carrier to the center of the data bands, and by simultaneously compensating for the effects of polarization mode dispersion, the provided system and method simulate the advantages of homodyne reception using a local oscillator. The deleterious effects of chromatic dispersion on the data signals within the data bands are also compensated for by applying a corrective function to the data signals which precisely counteracts the effects of chromatic dispersion.
    Type: Grant
    Filed: April 17, 2014
    Date of Patent: March 31, 2015
    Assignee: Teradvance Communications LLC
    Inventors: Marcel F. C. Schemmann, Zoran Maricevic, Antonije R. Djordjevic, Darby Racey
  • Patent number: 8989600
    Abstract: A modulating apparatus includes a branch that branches input light; a first modulating unit that modulates the phase of a first branch obtained by the branch; a second modulating unit that modulates a second branch obtained by the branch; a third modulating unit that is connected in series to the first modulating unit, transmits the first branch without branching the first branch, modulates the phase of light transmitted by controlling a refractive index of the light transmitted; a fourth modulating unit that is connected in series to the second modulating unit, transmits the second branch without branching the second branch, and modulates the phase of a light transmitted by controlling a refractive index of the light transmitted; and a coupler that couples the first branch modulated by the first and the third modulating units and the second branch modulated by the second and the fourth modulating units, at different intensities.
    Type: Grant
    Filed: September 27, 2013
    Date of Patent: March 24, 2015
    Assignee: Fujitsu Optical Components Limited
    Inventor: Kenichi Nakamoto
  • Patent number: 8977119
    Abstract: The embodiments provide an automatic bias control method and apparatus for an optical transmitter. The apparatus includes: a detecting unit configured to monitor output optical power of an I/Q modulator of the optical transmitter; a calculating unit configured to calculate bias voltage indicating values of the I modulator, Q modulator and phase modulator of the I/Q modulator according to the output optical power and known modulation data; and an adjusting unit configured to adjust respectively Direct-Current (DC) bias voltages of the I modulator, Q modulator and phase modulator according to the bias voltage indicating values of the I modulator, Q modulator and phase modulator. With the embodiments, known modulation data are used to realize automatic bias control by monitoring the evenness of distribution of the power of output optical signals of the transmitter in the four quadrants of an I/Q plane.
    Type: Grant
    Filed: July 3, 2013
    Date of Patent: March 10, 2015
    Assignee: Fuijtsu Limited
    Inventors: Meng Yan, Zhenning Tao
  • Patent number: 8929745
    Abstract: A first clock modulator branches a light beam, varies a phase difference of the resulting light beams according to a first clock, and causes interference of the light beams. A second clock modulator branches a light beam from the first clock modulator and synchronized with the first clock, varies a phase difference of the resulting light beams according to a second clock, and causes interference of the light beams. A third clock modulator branches a light beam from the first clock modulator and inversely synchronized with the first clock, varies a phase difference of the resulting light beams according to a third clock, and causes interference of the light beams. The second clock and the first clock have identical cycles and differing phases. The third clock and the second clock have phases that differ by a 1/2 cycle. Four data modulators modulate the light beams from the clock modulators.
    Type: Grant
    Filed: June 24, 2013
    Date of Patent: January 6, 2015
    Assignee: Fujitsu Optical Components Limited
    Inventor: Toru Yamazaki
  • Publication number: 20140356002
    Abstract: The disclosure relates to a method for optical frequency-locked multi-carrier generation based on one directly-modulated laser (DML) and one phase modulator (PM) in cascade driven by sinusoidal waveform (at the same or different frequency). When the DML and PM is driven by the same frequency RF signal at 12.5 GHz, adopting this method, 16 optical subcarriers with 12.5-GHz frequency spacing are generated with power difference less than 3 dB. When the DML and PM is driven by the different frequency with DML at 12.5 Ghz and PM at 25 GHz, over 24 optical subcarriers are generated with 12.5-GHz frequency spacing and amplitude fluctuation less than 3 dB. The number of the generated optical subcarriers can be further increased when the driving power for the DML is increased.
    Type: Application
    Filed: May 15, 2014
    Publication date: December 4, 2014
    Applicant: ZTE (USA) INC.
    Inventors: Jianjun Yu, Ze Dong
  • Patent number: 8903253
    Abstract: A 2n-QAM (e.g. 16-QAM) optical modulator comprising cascaded I-Q modulators. The first I-Q modulator applies 2n?2 (e.g. 4) QAM to an optical signal, having a constellation diagram with the 2n?2 (e.g., 4) constellation points located in quadrant I. The second I-Q modulator subsequently applies a quaternary phase-shift keying (QPSK) modulation scheme to the optical signal, thereby rotating the constellation points of the 2n?2-QAM modulation scheme to quadrants II, III and IV, to produce a 2n-QAM modulation constellation diagram. The rotation causes the 2n-QAM modulator to inherently apply four quadrant differential encoding to the optical signal. A method of 2n-QAM optical modulation is also provided and optical signal transmission apparatus comprising the 2n-QAM optical modulator.
    Type: Grant
    Filed: September 8, 2008
    Date of Patent: December 2, 2014
    Assignee: Telefonaktiebolaget L M Ericsson (publ)
    Inventors: Marco Secondini, Fabio Cavaliere
  • Publication number: 20140321863
    Abstract: A technique in which an outgoing signal is encoded to have multiple signal levels to modulate a light source, in which respective signal levels are indicative of different signal states of more than one bit. The multi-level signal is transmitted on a passive optical network (PON) having passive splitters to split the modulated light to transmit the light having multiple signal levels to a plurality of destinations via the PON.
    Type: Application
    Filed: May 21, 2013
    Publication date: October 30, 2014
    Applicant: BROADCOM CORPORATION
    Inventor: Wael William Diab
  • Patent number: 8873970
    Abstract: A method for generating a 400 Gb/s single channel optical signal from multiple modulated subchannels includes carving respective modulated subchannels into return-to-zero RZ modulated subchannels having non-overlapping peaks with intensity modulators having a duty cycle less than 50%, and combining the subchannels into a single channel signal aggregating the bit rate of each of the subchannels. The subchannels are combined with a flat top optical component for increased subsequent receiver sensitivity.
    Type: Grant
    Filed: May 28, 2010
    Date of Patent: October 28, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Jianjun Yu, Dayou Qian, Philip Nan Ji, Ting Wang
  • Patent number: 8849125
    Abstract: A system receives traffic that includes four-bit symbols, the four-bit symbols being encoded using a four-bit phase modulation scheme; and processes the traffic to recover a four-bit symbol. The system also decodes the recovered four-bit symbol to obtain a three-bit symbol. The three-bit symbol is associated with a three-quadrature amplitude modulation (3QAM) scheme, and the decoding is performed without creating an error, within the traffic, when cycle slip occurs. The system outputs the traffic based on the three-bit symbol.
    Type: Grant
    Filed: June 29, 2012
    Date of Patent: September 30, 2014
    Assignee: Infinera Corporation
    Inventors: Han Henry Sun, Kuang-Tsan Wu
  • Patent number: 8842992
    Abstract: A communications device includes a transmitter device having an optical source configured to generate an optical carrier signal, a first E/O modulator coupled to the optical source and configured to modulate the optical carrier signal with an input signal having a first frequency, and a second E/O modulator coupled to the optical source and configured to modulate the optical carrier signal with a reference signal. The communications device includes an optical waveguide coupled to the transmitter device, and a receiver device coupled to the optical waveguide and including an O/E converter coupled to the optical waveguide and configured to generate an output signal comprising a replica of the input signal at a second frequency based upon the reference signal.
    Type: Grant
    Filed: March 7, 2012
    Date of Patent: September 23, 2014
    Assignee: Harris Corporation
    Inventors: Charles Middleton, Richard DeSalvo, Peter S. Scheuter
  • Patent number: 8842997
    Abstract: Return To Zero (RZ) shaping is performed for a first I/Q modulator whose output corresponds to a first polarization component using a first two digital-to-analog convertors (DACs), each of which is sampled at approximately twice a modulation symbol rate or more and has an output with a first interleaving order that interleaves one of a first pair of intended drive signal patterns and zeros. RZ shaping is also performed for a second I/Q modulator whose output corresponds to a second polarization component using a second two DACs, each sampled at approximately twice the modulation symbol rate or more and having a second interleaving order that interleaves zeros and one of a second pair of intended drive signal patterns, the second interleaving order opposite the first interleaving order. The first polarization and the second polarization may be combined, thereby forming an Interleaved Return To Zero (IRZ) Polarization Division Multiplexed (PDM) signal.
    Type: Grant
    Filed: January 6, 2011
    Date of Patent: September 23, 2014
    Assignee: Alcatel Lucent
    Inventors: Xiang Liu, Chandrasekhar Sethumadhavan
  • Publication number: 20140255045
    Abstract: An optical transmitter includes a laser and an external modulator that is used to modulate the optical signal using amplitude modulation (AM). The AM is accompanied by frequency modulation (FM) of the output signal that is generally detrimental to system performance. Both the laser and the modulator are driven by an RF input signal, where part of this RF signal is common. By adjusting the relative drive signals the FM response to the modulator drive signal can be cancelled by a laser drive signal or adjusted to a preferred value.
    Type: Application
    Filed: March 7, 2014
    Publication date: September 11, 2014
    Applicant: ARRIS Solutions, Inc.
    Inventor: Marcel F. Schemmann
  • Patent number: 8831438
    Abstract: An apparatus for transmitting visible light communication data is provided, the apparatus including a common modulation unit generating a modulated signal for transmitting a first visible light communication data, a plurality of individual modulation units generating modulated signals for transmitting a plurality of second visible light communication data, and a plurality of light emitting units receiving the modulated signals from the plurality of individual modulation units, respectively, and outputting visible light signals, wherein an output of the common modulation unit is the input as an output control signal of the individual modulation units.
    Type: Grant
    Filed: September 29, 2009
    Date of Patent: September 9, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Sung-Bum Park, Yun-Je Oh, Dae-Kwang Jung
  • Patent number: 8831439
    Abstract: Consistent with the present disclosure, data, in digital form, is received by a transmit nodes of an optical communication, and converted to analog signal by a digital-to-analog converter (DAC) to drive a modulator. The modulator, in turn, modulates light at one of a plurality of wavelengths in accordance with the received data. The modulated light is then transmitted over an optical communication path to a receive node. At the receive node, the modulated optical signal, as well as other modulated optical signals are supplied to a photodetector circuit, which receives additional light at one of the optical signal wavelengths from a local oscillator laser. An analog-to-digital converter (ADC) is provided in the receive node to convert the electrical signals output from the photodetector into digital form. The output from the ADC is then filtered in the electrical domain, such that optical demultiplexing of individual channels is unnecessary.
    Type: Grant
    Filed: October 5, 2010
    Date of Patent: September 9, 2014
    Assignee: Infinera Corporation
    Inventors: Kuang-Tsan Wu, John D. McNicol, David F. Welch, Stephen G. Grubb, Pierre Mertz
  • Patent number: 8824900
    Abstract: A method for generating an optical single sideband signal comprising the steps of splitting an optical field into two parts and introducing a relative phase delay of +/??/4 radians in each direction of transmission to one of the parts, intensity reflection-modulating each part with electrical signals having a relative phase delay of +/??/2 radians and then recombining the reflection-modulated signals.
    Type: Grant
    Filed: March 18, 2010
    Date of Patent: September 2, 2014
    Assignee: Huawei Technologies Co., Ltd.
    Inventors: Peter Healey, David William Smith, Graeme Douglas Maxwell
  • Patent number: 8818205
    Abstract: A modulation method, especially an optical modulation method, using the principle of discrete IQ modulation. The modulation method includes generating a carrier signal (Sc) and splitting the carrier signal at a splitting position in an I branch signal and a Q branch signal; modulating the amplitude of the I branch signal according to a first modulation signal and modulating the amplitude of the Q branch signal according to a second modulation signal, each of the first and second modulation signals being arranged to adopt a given number of values according to a given number of constellation points of a given modulation scheme; phase shifting the signal in the Q branch versus the signal in the I branch; and combining the signals in the I branch and Q branch at a combining position. The combined modulated signal (Stx,mod) is arranged to be transmitted over a transmission path.
    Type: Grant
    Filed: December 20, 2011
    Date of Patent: August 26, 2014
    Assignee: ADVA Optical Networking SE
    Inventor: Michael Eiselt
  • Patent number: 8818203
    Abstract: An optical modulator includes a light input/output unit receiving an incident optical signal which has not been modulated, splitting the incident optical signal into a first optical signal and a second optical signal, and transmitting the first and second optical signals to a first path and a second path, respectively, of an optical waveguide. A phase shifter is positioned in at least one of the first and second paths and modulates a phase of at least one of the first and second optical signals, which have been received through the first and second paths, respectively, in response to an electrical signal. A phase-modulated signal is output. A reflective grating coupler reflects signals respectively received through the first and second paths back along the first and second paths respectively.
    Type: Grant
    Filed: December 7, 2011
    Date of Patent: August 26, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Ho-Chul Ji, Kyoung Ho Ha, Dong Jae Shin, Jung Hyung Pyo, Kwang Hyun Lee
  • Patent number: 8805203
    Abstract: A de-emphasis format signal generator can be configured to combine first and second electrical non-de-emphasis formatted signals provided to first and second optical modulators, coupled in parallel with one another, to provide a combined optical signal having a de-emphasis format. Accordingly, three aspects of a de-emphasis formatted signal, including a de-emphasis delay aspect, a de-emphasis attenuation aspect, and a de-emphasis combining aspect, can provided separately and in different domains (such as in the electrical domain and in the optical domain) which can be combined with one another to provide an output de-emphasis formatted optical signal.
    Type: Grant
    Filed: July 7, 2011
    Date of Patent: August 12, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Dong Jae Shin, Kwang Hyun Lee, Jung Hyung Pyo, Kyoung Ho Ha, Ho-Chul Ji
  • Publication number: 20140219663
    Abstract: Embodiments relate to communicating data by varying a frequency of an amplitude modulated light source. Embodiments may comprise logic such as hardware and/or code to vary a frequency of an amplitude-modulated electromagnetic radiator such as a visible light source, an infrared light source, or an ultraviolet light source. For instance, a visible light source such as a light emitting diode (LED) may provide light for a room in a commercial or residential building. The LED may be amplitude modulated by imposing a duty cycle that turns the LED on and off. In some embodiments, the LED may be amplitude modulated to offer the ability to adjust the intensity of the light emitted from the LED. Embodiments may receive a data signal and adjust the frequency of the light emitted from the LED to communicate the data signal via the light. In many embodiments, the data signal may be communicated via the light source at frequencies that are not perceivable via a human eye.
    Type: Application
    Filed: September 30, 2011
    Publication date: August 7, 2014
    Inventor: Richard D. Roberts
  • Patent number: 8798480
    Abstract: Structures and methods of generating 8-QAM signals through the effect of a cascaded I/Q modulator and Mach-Zhender modulator. The 8-QAM signals are generated by applying one binary sequence to the dual-drive Mach-Zehnder modulator (MZM) and two binary sequences to the I/Q modulator. Operationally, the I/Q modulator generates QPSK constellation(s), while the dual drive MZM either maintains the QPSK constellation at an out ring, or attenuates its amplitude to the inner ring and rotates its phase by ?/4 phase depending on the binary data it was driven by.
    Type: Grant
    Filed: October 5, 2012
    Date of Patent: August 5, 2014
    Assignee: NEC Laboratories America, Inc.
    Inventors: Yue-Kai Huang, Ezra Ip, Dayou Qian
  • Patent number: 8798481
    Abstract: In accordance with embodiments of the present disclosure, a method for compensation of noise in an optical device is provided. The method may include calculating noise present in an optical carrier signal. The method may also include generating quadrature amplitude modulation input signals, the quadrature amplitude modulation input signals each including a term for compensation of the noise based on the calculated noise. The method may further include modulating the optical carrier signal to generate a modulated optical signal based on quadrature amplitude modulation input signals.
    Type: Grant
    Filed: December 14, 2010
    Date of Patent: August 5, 2014
    Assignee: Fujitsu Limited
    Inventors: Inwoong Kim, Olga I. Vassilieva
  • Patent number: 8774568
    Abstract: Provided is an optical module. The optical module includes: an optical bench having a first trench of a first depth and a second trench of a second depth that is less than the first depth; a lens in the first trench of the optical bench; at least one semiconductor chip in the second trench of the optical bench; and a flexible printed circuit board covering an upper surface of the optical bench except for the first and second trenches, wherein the optical bench is a metal optical bench or a silicon optical bench.
    Type: Grant
    Filed: June 7, 2011
    Date of Patent: July 8, 2014
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Young-Tak Han, Jang Uk Shin, Sang-Pil Han, Sang Ho Park, Yongsoon Baek
  • Patent number: 8750722
    Abstract: Consistent with the present disclosure, a wavelength division multiplexed (WDM) optical communication system including on-off-keying (OOK) transmitters, for example, may be upgraded to include advanced modulation format transmitters, such as quadrature phase shift keying (QPSK) transmitters. Rather than replace all the OOK transmitters with QPSK transmitters at once, each OOK transmitter is replaced with a lower rate modulation format transmitter, such as a binary phase shift keying (BPSK) transmitter, as capacity needs increase. The BPSK transmitters supply (BPSK) optical signals that are more tolerant of noise caused by cross phase modulation (XPM) induced by OOK signals. Accordingly, such BPSK optical signals have fewer associated data detection errors in the receiver. Moreover, BPSK modulated optical signals induce little XPM-related noise in co-propagating QPSK modulated optical signals.
    Type: Grant
    Filed: December 24, 2010
    Date of Patent: June 10, 2014
    Assignee: Infinera Corporation
    Inventors: Vinayak Dangui, Matthew L. Mitchell
  • Publication number: 20140147119
    Abstract: An optical signal processing apparatus includes a mixer and a first optical modulator. The mixer modulates a carrier signal of a first specific frequency received from a first oscillator with an information signal to generate a subcarrier modulated signal. The first optical modulator optically modulates, with the subcarrier modulated signal received from the mixer, carrier light optically modulated by a second optical modulator at a second specific frequency received from a second oscillator to generate and output modulated carrier light.
    Type: Application
    Filed: September 4, 2013
    Publication date: May 29, 2014
    Applicant: FUJITSU LIMITED
    Inventors: Shigeki WATANABE, Tomoyuki KATO
  • Patent number: 8737843
    Abstract: An optical homodyne communication system and method in which a side carrier is transmitted along with data bands in an optical data signal, and upon reception, the side carrier is boosted, shifted to the center of the data bands, and its polarization state is matched to the polarization state of the respective data bands to compensate for polarization mode dispersion during transmission. By shifting a boosted side carrier to the center of the data bands, and by simultaneously compensating for the effects of polarization mode dispersion, the provided system and method simulate the advantages of homodyne reception using a local oscillator. The deleterious effects of chromatic dispersion on the data signals within the data bands are also compensated for by applying a corrective function to the data signals which precisely counteracts the effects of chromatic dispersion.
    Type: Grant
    Filed: January 5, 2012
    Date of Patent: May 27, 2014
    Assignee: Teradvance Communications, LLC
    Inventors: Marcel F.C. Schemmann, Zoran Maricevic, Antonije R. Djordjevic, Darby Racey
  • Patent number: 8731409
    Abstract: An optical signal transmitter includes: first outer modulator to generate first modulated optical signal, the first outer modulator including a pair of optical paths and a first phase shifter to give phase difference to the pair of optical paths; second outer modulator to generate second modulated optical signal, the second outer modulator including a pair of optical paths and a second phase shifter to give phase difference to the pair of optical paths; combiner to generate polarization multiplexed optical signal by combining the first and second modulated optical signals; phase controller to control the phase difference by the first phase shifter to A??? and control the phase difference by the second phase shifter to A+??; and power controller to control at least one of the first and second outer modulators based on AC component of the polarization multiplexed optical signal.
    Type: Grant
    Filed: June 24, 2013
    Date of Patent: May 20, 2014
    Inventors: Yuichi Akiyama, Noriaki Mizuguchi
  • Publication number: 20140133868
    Abstract: An optical modulator includes a splitter, phase modulators, amplitude modulators, intensity modulators, and a combiner. The splitter is configured to receive light, and split the light into portions of the light. Each of the phase modulators is configured to receive a corresponding one of the portions of the light, and modulate a phase of the portion of the light to provide a phase-modulated signal. Each of the amplitude modulators is configured to receive a corresponding one of the phase-modulated signals, and modulate an amplitude of the phase-modulated signal to provide an amplitude-modulated signal. Each of the intensity modulators is configured to receive a corresponding one of the amplitude-modulated signals, and modulate an intensity of the amplitude-modulated signals to provide an intensity-modulated signal. The combiner is configured to receive the intensity-modulated signals, combine the intensity-modulated signals into a combined signal, and output the combined signal.
    Type: Application
    Filed: November 13, 2012
    Publication date: May 15, 2014
    Applicant: Infinera Corporation
    Inventor: Infinera Corporation
  • Patent number: 8718486
    Abstract: In various embodiments, a monolithic integrated transmitter, comprising an on-chip laser source and a modulator structure capable of generating advanced modulation format signals based on amplitude and phase modulation are described.
    Type: Grant
    Filed: February 7, 2013
    Date of Patent: May 6, 2014
    Assignee: Freedom Photonics, LLC.
    Inventors: Jonathon Barton, Leif Johansson, Milan Mashanovitch
  • Patent number: 8718485
    Abstract: In a quantum cryptographic transmitter (11), a phase modulator (1103, 1104) and an LN intensity modulator (1105) apply optical phase modulation and light intensity modulation to an optical signal based on desired data to generate a desired optical signal to be transmitted to a quantum cryptographic receiver (13). Based on the number of photons detected from the desired optical signal, a bias control circuit (1108) controls an operating point in light intensity modulation of the LN intensity modulator (1105).
    Type: Grant
    Filed: July 9, 2008
    Date of Patent: May 6, 2014
    Assignee: NEC Corporation
    Inventors: Akihiro Tanaka, Akio Tajima, Seigo Takahashi, Wakako Maeda
  • Patent number: 8718484
    Abstract: An optical transmitter for generating a modulated optical signal for transmission over dispersive fiber optic links in which a first information-containing radio frequency signal input is applied to a modulation circuit for directly modulating a semiconductor laser with the signal input. The output of the laser is applied to a phase modulator to which a second information-containing radio frequency signal is applied.
    Type: Grant
    Filed: October 31, 2007
    Date of Patent: May 6, 2014
    Assignee: Emcore Corporation
    Inventors: John Dallesasse, John Iannelli, Daniel McGlynn