Heterodyne Patents (Class 398/204)
  • Patent number: 10243672
    Abstract: Methods and systems for waveguide delay based equalization with current and optical summing in optical communication are disclosed and may include an optoelectronic receiver including a directional coupler, two or more photodiodes, and one or more current mirrors. The optoelectronic receiver may be operable to: receive an input optical signal; split the input optical signal into first and second optical signals using the directional coupler; generate a first electrical from the first optical signal using a first photodiode; generate a second electrical signal from the second optical signal using a second photodiode; amplify the second electrical signal using the current mirror; and sum the first electrical signal with the amplified second electrical signal. The optoelectronic receiver may be operable to delay the first optical signal before generating the first electrical signal, using a waveguide delay.
    Type: Grant
    Filed: June 28, 2017
    Date of Patent: March 26, 2019
    Assignee: Luxtera, Inc.
    Inventors: Simon Pang, Joseph Balardeta
  • Patent number: 10209127
    Abstract: A method. The method may include transmitting an optical noise signal to a first photodetector and a second photodetector within an optical receiver circuit that includes a transimpedance amplifier circuit. The method may further include measuring, in response to transmitting the optical noise signal, a power output from the optical receiver circuit. The method may further include determining, using the power output, a difference in photodetector responsivity between the first photodetector and the second photodetector. The method may further include adjusting, using a transimpedance gain controller, an amplifier gain within the optical receiver circuit to decrease a difference in photodetector responsivity between the first photodetector and the second photodetector.
    Type: Grant
    Filed: November 5, 2015
    Date of Patent: February 19, 2019
    Assignee: Ciena Corporation
    Inventors: Tom Luk, Christopher Falt, Sean Sebastian O'Keefe
  • Patent number: 10162245
    Abstract: A sensing system adapted to receive backscattered signal from a sensing fiber includes a first Faraday rotator mirror; a second Faraday rotator mirror; an optical hybrid coupled to the Faraday rotator mirrors, wherein one of the mirrors is coupled with an optical path difference; a 3-port optical circulator coupled to the sensing fiber and the optical hybrid; a first photodetector coupled to the circulator; and three photodetectors coupled to the optical hybrid.
    Type: Grant
    Filed: May 16, 2017
    Date of Patent: December 25, 2018
    Assignee: NEC Corporation
    Inventors: Philip Nan Ji, Ting Wang
  • Patent number: 10103816
    Abstract: In a method and system for decoding a differential M-ary phase or quadrature amplitude modulated signal, the incoming signal is decoded according to a plurality of different decoding rules, wherein said plurality of decoding rules correspond to different values of a resulting frequency difference or mismatch between a signal frequency and a local oscillator reference frequency. The invention allows to increase a tolerance window for the maximal allowable frequency offset, and thus helps to speed up an initial locking process or to allow for equipment which has a lower tuning granularity.
    Type: Grant
    Filed: August 12, 2015
    Date of Patent: October 16, 2018
    Assignee: Xieon Networks S.a.r.l.
    Inventor: Harald Rohde
  • Patent number: 10056979
    Abstract: An optical transmission device as the first optical transmission device includes a light source to output light, an optical transmitter to transmit first information regarding a reception characteristic and power consumption of the first optical transmission device to a second transmission device, an optical receiver to receive second information regarding a reception characteristic and power consumption of the second optical transmission device, an optical branching circuit to branch the light output from the light source into transmission light for the optical transmitter and local light for coherent reception by the optical receiver, and vary power of the transmission light and power of the local light individually, and a processor to control a driving condition of the optical branching circuit, based on the first information and the second information, the power of the transmission light and the power of the local light varying in accordance with the driving condition.
    Type: Grant
    Filed: August 29, 2017
    Date of Patent: August 21, 2018
    Assignee: FUJITSU LIMITED
    Inventor: Miki Onaka
  • Patent number: 10014953
    Abstract: An optical receiver circuit includes: a substrate; and an optical waveguide device that is formed on the substrate. The optical waveguide device includes: a first optical splitter section branching the signal light into a first signal light propagation waveguide and a second signal light propagation waveguide and; a second optical splitter section branching the local-oscillator light into a first local-oscillator light propagation waveguide and a second local-oscillator light propagation waveguide; a first optical coupler section that combines the signal light propagating through the first signal light propagation waveguide and the local-oscillator light propagating through the first local-oscillator light propagation waveguide with each other; a second optical coupler section that combines the signal light propagating through the second signal light propagation waveguide and the local-oscillator light propagating through the second local-oscillator light propagation waveguide with each other.
    Type: Grant
    Filed: December 20, 2016
    Date of Patent: July 3, 2018
    Assignee: FUJIKURA LTD.
    Inventor: Kensuke Ogawa
  • Patent number: 9929811
    Abstract: Methods and systems for an optical connection service interface may include, in an optical data link comprising an optical fiber, a local control system, first and second transceivers at ends of the optical fiber, generating a control signal for the local control system at a low frequency and communicating, utilizing the optical fiber, an optical data signal at a high frequency and an optical service signal for an Optical Connection Service interface (OCSi) at an intermediate frequency. An optical signal may be modulated at the intermediate frequencies for the OCSi, and may be modulated and communicated to the second transceiver. The communicated modulated signal and the optical data signal may be detected utilizing a photodetector in the second transceiver. The detected optical signal may be demodulated, and an optical power of the optical data signal may be configured based on the demodulated signal.
    Type: Grant
    Filed: October 5, 2016
    Date of Patent: March 27, 2018
    Inventors: Gianlorenzo Masini, Joseph Balardeta, Scott Denton
  • Patent number: 9800349
    Abstract: An object of the present invention is to provide an optical 90-degree hybrid circuit which is capable of easily adjusting the optical power ratio between signal and local oscillator and suppresses an optical system of an optical receiver becoming complex and optical receivers using the same.
    Type: Grant
    Filed: March 28, 2013
    Date of Patent: October 24, 2017
    Assignee: SUMITOMO OSAKA CEMENT CO., LTD.
    Inventors: Yuji Hayami, Toshio Kataoka
  • Patent number: 9781516
    Abstract: Disclosed is a transparent electronic speaker device, including a transparent speaker, a touch control panel and a display panel which are sequentially stacked. The touch control panel provides a touch control function, and the display panel possesses a display function. The transparent speaker includes an upper conductive plate, a lower conductive plate and a transparent piezoelectric film sandwiched between the upper and lower conductive plates. The display panel generates and transfers a voltage driving signal through an electrical connection to the upper and lower conductive plates for actuating the transparent piezoelectric film to perform piezoelectric action, thereby generating vibration and sound. Therefore, the present invention not only integrates the functions of speaker, touch control and display, but also improves sound quality by use of the transparent piezoelectric film covering the whole electronic device without deteriorating display quality.
    Type: Grant
    Filed: September 23, 2015
    Date of Patent: October 3, 2017
    Assignee: IBASE TECHNOLOGY INC.
    Inventor: You-Nan Chen
  • Patent number: 9692545
    Abstract: An optical reception apparatus (1) of the present invention includes: a local oscillator (11) outputting local oscillation light (22); an optical mixer (12) receiving a multiplexed optical signal (21) and the local oscillation light, and selectively outputting an optical signal (23) corresponding to the wavelength of the local oscillation light from the multiplexed optical signal; a photoelectric converter (13) converting the optical signal (23) output from the optical mixer into an electric signal (24); a variable gain amplifier (15) amplifying the electric signal (24) to generate an output signal (25) whose output amplitude is amplified to a certain level; a gain control signal generating circuit (16) generating a gain control signal (26) for controlling the gain of the variable gain amplifier (15); and a monitor signal generating unit (17) generating a monitor signal (27) corresponding to the power of the optical signal (23) using the gain control signal (26).
    Type: Grant
    Filed: March 27, 2014
    Date of Patent: June 27, 2017
    Assignee: NEC Corporation
    Inventor: Yusuke Yamauchi
  • Patent number: 9692520
    Abstract: An optical modulator combines and inputs a signal light propagating through the optical network and a control light having information concerning the optical network to a nonlinear optical medium. The optical modulator modulates the signal light according to changes in intensity of the control light, in the nonlinear optical medium.
    Type: Grant
    Filed: February 9, 2015
    Date of Patent: June 27, 2017
    Assignee: FUJITSU LIMITED
    Inventor: Shigeki Watanabe
  • Patent number: 9667033
    Abstract: The invention relates to a laser device, comprising a laser configured to generate laser light and a laser control module configured to receive at least a portion of the laser light generated by the laser, to generate a control signal and to feed the control signal back to the laser for stabilizing the frequency, wherein the laser control module comprises a tunable frequency discriminating element which is preferably continuously frequency tunable, and where the laser control module is placed outside the laser cavity.
    Type: Grant
    Filed: February 8, 2013
    Date of Patent: May 30, 2017
    Assignee: NKT PHOTONICS A/S
    Inventors: Jens E. Pedersen, Poul Varming, Christian V. Poulsen, Thomas O. Fagerhøj, Bjarke Gøth, Henrik Sørensen
  • Patent number: 9584246
    Abstract: The present invention relates to a wavelength division multiplexing optical receiver and eliminates excess loss of one polarization component while eliminating the need for a polarization-independent operation of a light receiver. An input waveguide, made of a silicon wire waveguide, is connected to a loop waveguide equipped with a polarization rotator over a polarization beam splitter. A ring waveguide equipped with an output waveguide configuring an add-drop ring resonator array is optically connected to the loop waveguide. The output light from ports at both sides of the output waveguide is incident onto first and second light-receiving surfaces of a light receiver such that the optical distances are equal to each other.
    Type: Grant
    Filed: September 3, 2015
    Date of Patent: February 28, 2017
    Assignee: FUJITSU LIMITED
    Inventor: Seokhwan Jeong
  • Patent number: 9564964
    Abstract: An optimization unit in an optical receiver divides a symbol region out of a plurality of symbol regions into which signal points that specifies symbol information included in an optical signal are classified, into a plurality of division regions from the symbol center coordinate of the symbol region. Moreover, the optimization unit accumulates the signal points of the symbol information for every division region in the symbol region. Furthermore, based on the accumulated number of signal points for every division region, the optimization unit controls the average length of a phase estimation unit when the phase noise of the optical signal is calculated.
    Type: Grant
    Filed: June 3, 2014
    Date of Patent: February 7, 2017
    Assignee: FUJITSU LIMITED
    Inventors: Taku Saito, Katsumi Fukumitsu, Osamu Takeuchi, Hirofumi Araki, Kanji Naito, Shoichi Murakami
  • Patent number: 9537579
    Abstract: The invention relates to a noise compensation system, configured for compensating phase noise in coherent optical communications, and to a method for compensating phase noise.
    Type: Grant
    Filed: August 28, 2012
    Date of Patent: January 3, 2017
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Bengt-Erik Olsson, Christina Larsson
  • Patent number: 9515736
    Abstract: According to one embodiment, a system for transmitting differential optical signals can include an optical modulation device, a multi-core optical waveguide, and a balanced optical receiver. The optical modulation device can include at least one optical input port and multiple optical output ports. The optical modulation device can transform the optical input signal into multiple complimentary modulated optical signals that are transmitted from the multiple optical output ports. The multi-core optical waveguide can include multiple cores disposed within a cladding material. The multiple cores, the cladding material, or both can be configured to mitigate transmission of optical energy between the multiple cores. The balanced optical receiver can include multiple photodetectors. The balanced optical receiver can be communicatively coupled to the multiple cores of the multi-core optical waveguide.
    Type: Grant
    Filed: May 22, 2013
    Date of Patent: December 6, 2016
    Assignee: Corning Incorporated
    Inventors: Brewster Roe Hemenway, Jr., Ioannis Roudas
  • Patent number: 9432141
    Abstract: An optical network unit has a tunable laser. The tunable laser is tunable such that a point-to-point connection to another optical network unit is established via an optical fiber. There is also provided a method for processing data in an optical network and a corresponding communication system. The tunable laser can be adjusted based on a detected collision, and a frequency grid can be supplied from a centralized component.
    Type: Grant
    Filed: May 16, 2011
    Date of Patent: August 30, 2016
    Assignee: Xieon Networks S.a.r.l.
    Inventors: Erich Gottwald, Harald Rohde
  • Patent number: 9377356
    Abstract: A photon detection system including a photon detector configured to detect single photons, a signal divider to divide the output signal of the photon detector into a first part and a second part, wherein the first part is substantially identical to the second part, a delay mechanism to delay the second part with respect to the first part, and a combiner to combine the first and delayed second parts of the signal such that the delayed second part is used to cancel periodic variations in the first part of the output signal.
    Type: Grant
    Filed: October 17, 2014
    Date of Patent: June 28, 2016
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Zhiliang Yuan, Andrew James Shields
  • Patent number: 9316534
    Abstract: A reconfigurable photonic integrated circuit focal plane array (RPIC-FPA) includes detectors and photonic integrated circuit coupled to the detectors that are configured to mix a return signal beam with local oscillator (LO) beams to produce a combined beam and direct the combined beam to the detectors. The LO beams have reconfigurable optical properties enabled by the RPIC-FPA. The LO beams are individually addressed to switch the detectors between a direct detection mode and various coherent detection modes based on adjustments to the optical properties of the LO beams. In the coherent detection mode, the controller is configured to mix the return signal beam with the LO beam having adjusted optical properties to produce the combined beam, and, in the direct detection mode, the controller is configured to disable the LO beams based on adjustments to the optical properties and to direct the return signal beam to the detectors without mixing.
    Type: Grant
    Filed: January 28, 2014
    Date of Patent: April 19, 2016
    Assignee: Lockheed Martin Coherent Technologies, Inc.
    Inventors: Piotr Konrad Kondratko, Philip Gatt, John Glennon, Brian Carroll Redman, Paul Suni
  • Patent number: 9270383
    Abstract: An optical receiver may receive input signals carried by respective sub-carriers. The optical receiver may determine, based on the input signals, a compensation value to be used to modify an input signal. The optical receiver may use the compensation value to adjust the input signal to form a modified input signal. The compensation value may be used to modify a frequency or a phase of the input signal. The optical receiver may determine, based on the modified input signal, a phase estimate value that represents an estimated phase associated with the input signal. The optical receiver may combine the compensation value and the phase estimate value to form a phase adjustment signal, may combine the input signal and the phase adjustment signal to form an output signal, and may output the output signal.
    Type: Grant
    Filed: March 31, 2014
    Date of Patent: February 23, 2016
    Assignee: Infinera Corporation
    Inventors: Han H. Sun, Sandy Thomson, Yuejian Wu, Kuang-Tsan Wu
  • Patent number: 9246581
    Abstract: A communication light detecting structure includes a communication optical fiber configured to transmit communication light; a leakage optical fiber optically connected to the middle of the communication optical fiber via optical connection portions, the leakage optical fiber being different in core refractive index from the communication optical fiber; and a light detecting unit configured to detect part of the communication light leaking from the optical connection portions as leakage light. A communication light detecting optical connector includes the communication light detecting structure. A communication light detecting optical cable includes the communication light detecting structure. The communication optical fiber and the leakage optical fiber may have the same core diameter. The communication optical fiber and the leakage optical fiber may have the same cladding refractive index.
    Type: Grant
    Filed: April 3, 2014
    Date of Patent: January 26, 2016
    Assignee: HITACHI METALS, LTD.
    Inventors: Kanako Suzuki, Yoshihiro Nakatani
  • Patent number: 9236940
    Abstract: A method of analyzing an input signal, the method including the steps of: (a) dividing a first input signal into first and second orthogonal signal polarization components; (b) dividing a second input signal into orthogonal first and second orthogonal local polarization components; (c) mixing the first orthogonal signal component with the second orthogonal local polarization component to provide a first mixed signal; (d) mixing the second orthogonal signal component with the first orthogonal local polarization component to provide a second mixed signal; (e) analyzing the first and second mixed signal to determine the polarization or phase information in the input signal.
    Type: Grant
    Filed: July 31, 2013
    Date of Patent: January 12, 2016
    Assignee: Finisar Corporation
    Inventor: Steven James Frisken
  • Patent number: 9235100
    Abstract: An integrated optical signal Synthesizer and Analyzer for optical communications, each formed on a single chip, is disclosed. The Synthesizer and Analyzer are both design to use a Dual-Polarization Quadrature Amplitude Modulation (QAM) for communication operating at high data rates. A communication system for data transmission having such synthesizer and the analyzer is also disclosed.
    Type: Grant
    Filed: September 3, 2012
    Date of Patent: January 12, 2016
    Assignee: Celight
    Inventor: Arkady Kaplan
  • Patent number: 9124370
    Abstract: A light emitting element drive circuit includes: a plurality of signal paths that respectively propagate a plurality of signals obtained by branching an input signal, a plurality of filters different in a frequency band to pass a signal; one or more amplifiers configured to amplify a signal, one or more delay circuits configured to delay a signal, and an addition circuit that adds a plurality of signals, the filter different in the frequency band being arranged in each of the plurality of signal paths, the delay circuit being arranged in one or more of the plurality of signal paths relatively low in the frequency band, the amplifier being arranged in one or more of the plurality of signal paths relatively high in the frequency band, and an output end of each of the plurality of signal paths being coupled to the addition circuit.
    Type: Grant
    Filed: August 9, 2013
    Date of Patent: September 1, 2015
    Assignee: FUJITSU LIMITED
    Inventors: Mariko Kase, Yukito Tsunoda
  • Patent number: 9077454
    Abstract: An optical detector for detecting an optical signal beam (OSB) modulated in a way that it includes an in-phase and/or a quadrature component, includes: a polarization beam splitter arranged to split the OSB into two polarized OSBs; a non-polarization beam splitter arranged to further split each of the two polarized OSBs into two split polarized OSBs; at least one birefringent element providing a phase shift, the birefringent element being arranged in a path of at least one polarized OSB and/or in a path of at least one split polarized OSB so that an in-phase and quadrature phase offset between two split polarized OSBs originating from the same polarized OSB is formed in output signal beams; and at least two detection means arranged to receive at least one output signal beam that includes a in-phase and/or quadrature component of the OSB.
    Type: Grant
    Filed: March 5, 2012
    Date of Patent: July 7, 2015
    Assignee: KARLSRUHER INSTITUT FUR TECHNOLOGIE
    Inventors: Jingshi Li, Matthias Lauermann, Sven Schüle, Juerg Leuthold, Wolfgang Freude
  • Patent number: 9031419
    Abstract: A fiber optic system includes a transmitter for transmitting high-speed streaming electrical data to a receiver for receiving the high-speed data. In order to transmit multiple channels in the system at high-speeds, an electrical data signal is converted into multiple optical sub-signals. Each of the multiple optical sub-signals are transmitted at the common wavelength on multi-spatial mode media. The receiver receives the multiple optical sub-signals as a multi-spatial mode optical signal and separates the multi-spatial mode optical signal into branch signals having a common wavelength. The receiver mixes each of the branch signals with optical carrier waves having the common wavelength and converts the branch signals into electrical signals. Digital signal processing is used to recover the data sub-signals which are used to recover the original data signal.
    Type: Grant
    Filed: September 28, 2011
    Date of Patent: May 12, 2015
    Assignee: AT&T Intellectual Property I, L.P.
    Inventors: Sheryl Woodward, Martin Birk, Michael Brodsky, Lynn E. Nelson, Xiang Zhou, Mark D. Feuer
  • Patent number: 9020337
    Abstract: A local oscillation light source outputs locally-oscillated light. An light receiving unit phase-separates an input optical signal by making the optical signal interfere with the locally-oscillated light and outputs an analog electric signal corresponding to the phase-separated optical signal. An analog-to-digital converting unit converts the analog electric signal into a digital signal. A processing unit performs digital signal processing by using the digital signal. A failure detection unit determines whether or not the optical signal is being input to the light receiving unit, or detects a failure in the light receiving unit, the analog-to-digital converting unit or the processing unit based on light intensity of the optical signal, whether or not the analog electric signal can be generated in the light receiving unit, and an amplitude of the analog electric signal output from the light receiving unit.
    Type: Grant
    Filed: June 14, 2013
    Date of Patent: April 28, 2015
    Assignee: NEC Corporation
    Inventor: Takashi Tsubouchi
  • Patent number: 9020365
    Abstract: Current optical networks are engineered to handle amplifier noise and chromatic dispersion. Polarization mode dispersion occurs in optical networks due splitting of the light energy of a pulse propagating in a fiber into two modes. Compensating for polarization mode dispersion is a difficult and expensive task and hence only few commercial systems have been deployed to deal with this issue. A polarization mode dispersion compensation module according to an example embodiment of the present invention compensates for polarization mode dispersion by determining a performance metric related to an error rate of an optical signal in at least one polarization mode in a filtered state. Based on the performance metric, a control vector is determined to control the optical signal in the at least one polarization mode in the filtered state. The control vector is then applied to a polarization effecting device to compensate for polarization mode dispersion.
    Type: Grant
    Filed: April 8, 2008
    Date of Patent: April 28, 2015
    Assignee: Tellabs Operations, Inc.
    Inventors: Richard C. Younce, Julia Y. Larikova
  • Patent number: 9014575
    Abstract: In a sampling clock synchronizing apparatus, an A/D converter converts an analog signal to a digital signal based on a sampling clock, and a processor compensates a band limitation due to spectral narrowing by filter characteristics of characteristics opposite to those of the spectral narrowing with respect to a signal produced from the A/D converter subjected to the spectral narrowing, and detects a phase shift in the sampling clock based on a signal after the compensation of the spectral narrowing and synchronizes sampling timing.
    Type: Grant
    Filed: January 6, 2012
    Date of Patent: April 21, 2015
    Assignee: Fujitsu Limited
    Inventors: Hisao Nakashima, Takeshi Hoshida
  • Patent number: 9014566
    Abstract: An optical component contains a tunable laser. The tunable laser provides an optical local oscillator signal, and the tunable laser is directly modulated to provide a modulated optical data signal. In this manner we have optimization of the channel wavelength and obtain an optimized electrical and optical bandwidth utilization. Furthermore, a method for data processing is suggested.
    Type: Grant
    Filed: October 6, 2008
    Date of Patent: April 21, 2015
    Assignee: Xieon Networks S.a.r.l.
    Inventor: Erich Gottwald
  • Patent number: 9014573
    Abstract: A method for processing data in an optical network element are provided, wherein the optical network element comprises a local oscillator operating at a first frequency; wherein an incoming data stream is received at a second frequency; wherein the incoming data steam is processed using the first frequency; wherein a first pattern is searched in the incoming data stream; wherein a second pattern is searched in the incoming data stream; and wherein the first pattern corresponds to the first frequency being in the spectrum on one side of the second frequency and the second pattern corresponds to the first frequency being in the spectrum on the other side of the second frequency. Also, a corresponding optical network element and a communication system comprising at least one such optical network element are suggested.
    Type: Grant
    Filed: February 13, 2012
    Date of Patent: April 21, 2015
    Assignee: Xieon Networks S.a.r.l.
    Inventors: Harald Rohde, Thomas Treyer
  • Patent number: 8995836
    Abstract: A wavelength division multiplexing passive optical network (WPON) comprising an optical line terminal (OLT) and a plurality of optical network units (ONUs) coupled to the OLT via a power optical splitter. The OLT is configured to monitor wavelengths in use by the ONUs and to divide upstream traffic from the ONUs into multiple channels using tunable filters. Also disclosed is an OLT for a PON, the OLT comprising a plurality of receivers and a plurality of tunable filters corresponding to each of the receivers. The OLT also comprises channel control logic coupled to the tunable filters, wherein the channel control logic is configured to detect a plurality of wavelengths in use for upstream traffic in the PON and to divide the upstream traffic into multiple channels using the tunable filters. Included is a method for managing upstream traffic in a PON, the method comprising monitoring, by a processor, wavelengths in use for upstream traffic in the PON.
    Type: Grant
    Filed: July 11, 2011
    Date of Patent: March 31, 2015
    Assignee: Futurewei Technologies, Inc.
    Inventors: Ning Cheng, Frank J. Effenberger, Guo Wei
  • Patent number: 8989575
    Abstract: The present invention provides a signal detection method, including: receiving, by a frequency mixer, wavelength division multiplexing signals and a local oscillator signal, where a wavelength of the local oscillator signal and a wavelength of a target signal in the wavelength division multiplexing signals are the same; a frequency mixer performs interference on the wavelength division multiplexing signals through the local oscillator signal to obtain a coherent signal formed by the local oscillator signal and the target signal; sending the coherent signal to a transimpedance amplifier for amplification to obtain a voltage signal; and obtaining the power of the target signal according to a power amplitude of the voltage signal.
    Type: Grant
    Filed: August 29, 2012
    Date of Patent: March 24, 2015
    Assignee: Huawei Technologies Co., Ltd.
    Inventors: Haitao Ye, Shuangyuan Wu, Weijian Chen, Yongzhong Wang
  • Patent number: 8989593
    Abstract: Consistent with an aspect of the present disclosure, an optical signal carrying data or information is supplied to photodetector circuitry that generates a corresponding analog signal. The analog signal may be amplified or otherwise processed and supplied to analog-to-digital conversion (ADC) circuitry, which samples the analog signal to provide a plurality of digital signals or samples. The timing of such sampling is in accordance with a clock signal supplied to the ADC circuitry. A phase detector is provided that detects and adjust the clock signal to have a desired phase based on frequency domain data that is output from a Fast Fourier transform (FFT) circuit that receives the digital samples. Preferably, the phase detector circuit is configured such that it need not receive all the frequency domain data output from the FFT at any given time in order to determine the clock phase.
    Type: Grant
    Filed: December 6, 2010
    Date of Patent: March 24, 2015
    Assignee: Infinera Corporation
    Inventors: Han Henry Sun, Kuang-Tsan Wu
  • Patent number: 8989603
    Abstract: A coherent optical receiver according to an exemplary aspect of the present invention includes a coherent optical receiving unit, a first waveform equalizing circuit compensating waveform distortion caused by characteristics of the coherent optical receiving unit and compensating chromatic dispersion in a predetermined range to an input signal, a second waveform equalizing circuit compensating chromatic dispersion of the input signal, and a controller monitoring a chromatic dispersion amount of the input signal and controlling a compensation coefficient regarding the chromatic dispersion compensation performed by each of the first waveform equalizing circuit and the second waveform equalizing circuit depending on the chromatic dispersion amount to be compensated.
    Type: Grant
    Filed: October 4, 2012
    Date of Patent: March 24, 2015
    Assignee: NEC Corporation
    Inventor: Makoto Shibutani
  • Patent number: 8983289
    Abstract: A method of recovering frequency and phase associated with an optical carrier signal in an optical communication system includes determining an estimated frequency offset based on a starting training sequence, determining a current frequency offset based on the estimated frequency offset and a current phase during steady-state operation of the optical communication system, determining a current frequency based on the current frequency offset, determining an estimated phase using training symbols inserted into the optical carrier signal, and determining the current phase associated with the optical carrier signal based on the estimated phase and a blind phase search algorithm. A corresponding systems and computer-readable device are also disclosed.
    Type: Grant
    Filed: December 19, 2012
    Date of Patent: March 17, 2015
    Assignee: AT&T Intellectual Property I, L.P.
    Inventor: Xiang Zhou
  • Patent number: 8977136
    Abstract: A receiver that includes a carrier recovery module that includes a reference signal generator that is arranged to generate a reference signal that estimates a carrier signal; a decision module that is arranged to demodulate a receiver input signal by the reference signal to provide a demodulated signal and to evaluate the demodulated signal to provide an decision module output signal that estimates the carrier signal; the reference signal generator includes a delay and rotation module that is arranged to delay receiver input signals to provide delayed receiver input signals and to align the delayed receiver input signals by a rotation that is responsive to the decision module output signal thereby providing aligned signals; and a multiplication and summation module that is arranged to generate the reference signal by calculating a weighted sum of the aligned signals.
    Type: Grant
    Filed: December 19, 2012
    Date of Patent: March 10, 2015
    Assignee: Technion Research and Development Foundation Ltd.
    Inventors: Netta Sigron, Igor Tselniker, Moshe Nazarathy
  • Patent number: 8965211
    Abstract: A system and method of digitizing an analog signal without an amplitude channel is disclosed. The system and method includes receiving an analog signal comprising a voltage v(t) and a frequency f1, producing a series of optical pulses at a sampling frequency f2 with a pulsed laser, splitting the series of optical pulses into a first optical signal and an optical reference signal, phase modulating the first optical signal with the analog signal to produce a sampled optical signal such that phase shifts between adjacent samples in the sampled optical signal does not exceed ? radians, and receiving the sampled optical signal and the optical reference signal at a photonic signal processor.
    Type: Grant
    Filed: September 29, 2011
    Date of Patent: February 24, 2015
    Assignee: Rockwell Collins, Inc.
    Inventors: Raymond Zanoni, Kim S. Jepsen, Oliver S. King, Mark A. Laliberte
  • Patent number: 8965221
    Abstract: A receiver includes: an extraction circuit to extract a phase fluctuation component common to phase data of two polarization components that are separated in a coherent reception of a polarization multiplexing phase modulation optical signal; and a correction circuit to correct the phase data of the two polarization components in accordance with the phase fluctuation component.
    Type: Grant
    Filed: May 31, 2012
    Date of Patent: February 24, 2015
    Assignee: Fujitsu Limited
    Inventors: Kazuo Hironishi, Takeshi Hoshida
  • Patent number: 8958706
    Abstract: A coherent optical communication device includes a demodulator configured to demodulate a reception signal; a local oscillator light optical source configured to generate local oscillator light used for demodulating the reception signal; a memory configured to store wavelength information; and a controller configured to control the local oscillator light optical source when the demodulator cannot receive the reception signal, so that a wavelength of the local oscillator light generated in the local oscillator light optical source is changed to a wavelength specified by the wavelength information stored in the memory.
    Type: Grant
    Filed: January 25, 2011
    Date of Patent: February 17, 2015
    Assignee: Fujitsu Limited
    Inventor: Takuji Maeda
  • Patent number: 8953951
    Abstract: This disclosure describes the Fast Chromatic Dispersion Estimation (FCDE) techniques which corrects for chromatic dispersion in high data rate optical communications systems such as some coherent optical communications systems. FCDE may utilize transform such as fast-Fourier transforms to estimate the chromatic dispersion. From an estimation of the chromatic dispersion, the techniques may determine filter tap coefficients for compensating the chromatic dispersion.
    Type: Grant
    Filed: June 19, 2012
    Date of Patent: February 10, 2015
    Assignee: Juniper Networks, Inc.
    Inventors: Philip A. Thomas, Christian Malouin, Theodore John Schmidt
  • Patent number: 8929749
    Abstract: Methods and systems of data symbol recovery in a coherent optical receiver of an optical communications system. A respective probabilistic phase error is calculated for each of a plurality of data symbol estimates. A phase rotation is calculated based on the probabilistic phase error estimates, using a filter function, and the phase rotation applied to at least one data symbol estimate to generate a corresponding rotated symbol estimate. Each rotated symbol estimate is processed to generate corresponding decision values of each data symbol.
    Type: Grant
    Filed: October 5, 2011
    Date of Patent: January 6, 2015
    Assignee: Ciena Corporation
    Inventors: Kim B. Roberts, Shahab Oveis Gharan, Amir Khandani
  • Publication number: 20140363176
    Abstract: An optical phase compensation device included in an optical receiver employing an intradyne detection method, includes a first optical phase error calculator configured to calculate a first optical phase error by averaging signal symbols of a first number of input main signals, a second optical phase error calculator configured to calculate a second optical phase error by averaging signal symbols of a second number of the main signals, wherein the second number is smaller than the first number, and a subtractor configured to subtract, from optical phase components of the main signals, one of a difference between the first optical phase error and the second optical phase error and a value obtained by multiplying the difference by a gain relative to the difference.
    Type: Application
    Filed: May 15, 2014
    Publication date: December 11, 2014
    Applicant: FUJITSU LIMITED
    Inventor: Noriaki MIZUGUCHI
  • Patent number: 8873973
    Abstract: A digital coherent receiver includes a sampling phase detector to detect a phase of a sampled digital signal, and a phase adjustor to adjust the sampling phase of the digital signal based upon the detected phase. The phase detector includes filters to equalize the digital signal with different equalization characteristics; sensitivity monitoring phase detectors, each connected to one of the filters and outputting a phase detection signal representing the phase of the output signal from the associated filter together with a sensitivity monitoring signal representing the sensitivity of the phase detection; sensitivity correction coefficient generators, each generating a sensitivity correction coefficient for correcting the associated phase detection signal using a square sum of the sensitivity monitoring signals; and an adder to add the phase detection signals that have been corrected by the sensitivity correction coefficients, and output a phase signal.
    Type: Grant
    Filed: April 13, 2012
    Date of Patent: October 28, 2014
    Assignee: Fujitsu Limited
    Inventors: Kosuke Komaki, Hisao Nakashima
  • Patent number: 8867930
    Abstract: Systems and methods for determining the envelope of a modulated signal using high bandwidth and low bandwidth samples of a hybrid signal. The hybrid signal is obtained by mixing the modulated signal with its carrier signal. The systems and methods of the present disclosure may be suitable for equivalent-time or real-time oscilloscopes.
    Type: Grant
    Filed: October 27, 2011
    Date of Patent: October 21, 2014
    Assignee: Queen's University at Kingston
    Inventors: David J. Krause, John C. Cartledge
  • Patent number: 8867911
    Abstract: A device able to evaluate a phase difference between I-component and Q-component of signal light generated by an optical hybrid is disclosed. The device includes a detector, a compensator and an evaluator. The detector detects positive and negative elements of each of the I-component and the Q-component. The compensator generates a compensated I-component and a compensated Q-component so as to keep the sum of positive and negative elements of each of components in constant. The evaluator determines the phase difference via an ellipsoid drawn by the compensated I- and Q-components.
    Type: Grant
    Filed: August 29, 2012
    Date of Patent: October 21, 2014
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventor: Yoshihiro Tateiwa
  • Patent number: 8861982
    Abstract: When designing a demodulator for a DPSK-modulated signal, it is required that optical phase modulation is performed fast and the demodulator has a long lifetime. To achieve this object, a delay line interferometer inside the demodulator performs adjustment of phase difference between two split lights caused to interfere, using a first optical phase modulation unit such as a Piezo actuator and a second optical phase modulation unit such as a heating element that operates slower in modulation speed than the first optical phase modulation unit and is slower in deterioration speed.
    Type: Grant
    Filed: January 6, 2011
    Date of Patent: October 14, 2014
    Assignee: Oclaro Japan, Inc.
    Inventors: Hideharu Mikami, Taichi Kogure
  • Patent number: 8855501
    Abstract: A method for carrier frequency recovery in an optical coherent transmission system is provided in which at least one kind of equalization of a received signal is performed in frequency domain, the method comprising: performing a frequency offset compensation in frequency domain on a received signal according to an estimated value of the frequency offset; obtaining the signal with the frequency offset compensated. Further, an optical coherent receiver is provided comprising: an equalization unit, adapted to perform at least one kind of optical distortion compensation of a received signal in frequency domain; a frequency offset compensation unit, adapted to perform the frequency offset compensation in frequency domain on a received signal according to an estimated value of the frequency offset to obtain the signal with frequency offset compensated.
    Type: Grant
    Filed: December 16, 2011
    Date of Patent: October 7, 2014
    Assignee: Huawei Technologies Co., Ltd.
    Inventor: Changsong Xie
  • Patent number: 8849130
    Abstract: One coherent optical receiver includes a 3×3 coupler for receiving a signal and a local oscillator into a first and a third input port respectively, and three detectors for detecting a respective output of the coupler to generate corresponding first, second and third detected signals. A detected signal is filtered by an Alternating Current (AC) coupler to generate a respective first, second or third filtered signal. An adder adds the first, the second and the third filtered signals to determine a directly detected signal term. A first subtractor subtracts the directly detected signal term from the first filtered signal to determine an in-phase signal. A second subtractor subtracts the directly detected signal term from the third filtered signal to determine a quadrature signal. A digital signal processor processes the in-phase signal and the quadrature signal to recover the optical signal.
    Type: Grant
    Filed: June 29, 2012
    Date of Patent: September 30, 2014
    Assignee: Alcatel Lucent
    Inventors: Chongjin Xie, Peter J. Winzer
  • Patent number: 8837957
    Abstract: An apparatus comprising a frequency-domain equalizer that has been iteratively generated to compensate for filtering effects of a wavelength selective switch, wherein the FDEQ is configured to process in a frequency domain digital samples of a polarization multiplexed phase-shift-keying signal that has been transported over an optical channel.
    Type: Grant
    Filed: January 12, 2012
    Date of Patent: September 16, 2014
    Assignee: Futurewei Technologies, Inc.
    Inventors: Zhuhong Zhang, Yanming Li, Chuandong Li, Fei Zhu