Patents by Inventor Mu Xu

Mu Xu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11223504
    Abstract: An optical network includes a transmitter portion configured to (i) precode an input digitized stream of symbols into a precoded symbol stream, (ii) pulse shape the precoded symbol stream with an eigenvalue channel matrix, and (iii) transmit the pulse shaped symbol stream over a digital optical link. The optical network further includes a receiver portion configured to (i) recover the pulse shaped symbol stream from the digital optical link, (ii) decompose eigenvalues of the eigenvalue channel matrix from the recovered symbol stream, and (iii) decode the decomposed symbol stream into an output symbol stream.
    Type: Grant
    Filed: May 4, 2020
    Date of Patent: January 11, 2022
    Assignee: Cable Television Laboratories, Inc.
    Inventors: Mu Xu, Zhensheng Jia, Peng-Chun Peng, Siming Liu, Feng Lu, Curtis Dean Knittle
  • Patent number: 11223421
    Abstract: A skew compensation system for a coherent optical communication network includes a transmitter and a receiver in operable communication with an optical transport medium of a coherent optical network. The transmitter includes a first transmitter-side tunable delay line configured to delay transmission of a first signal by a first skew amount, thereby producing a pre-compensated first signal. The receiver includes a first receiver-side tunable delay line configured to delay transmission of the pre-compensated first signal to a digital signal processor (DSP) of the receiver by a second skew amount, thereby producing a final signal that is both pre-compensated and post-compensated (i.e., fully compensated).
    Type: Grant
    Filed: February 3, 2021
    Date of Patent: January 11, 2022
    Assignee: Cable Television Laboratories, Inc.
    Inventors: Mu Xu, Junwen Zhang, Haipeng Zhang, Zhensheng Jia, Luis Alberto Campos
  • Patent number: 11146351
    Abstract: A communications network includes a central communication unit, an optical transport medium, and a plurality of remote radio base stations. The central communication unit generates, within a selected millimeter-wave frequency band, a plurality of adjacent two-tone optical frequency conjugate pairs. Each conjugate pair includes a first optical tone carrying a modulated data signal, and a second optical tone carrying a reference local oscillator signal. The optical transport medium transports the plurality of two-tone conjugate pairs to the plurality of radio base stations, and each base station receives at least one conjugate pair at an optical front end thereof. The optical front end separates the first optical tone from the second optical tone, and converts the first optical tone into a millimeter-wave radio frequency electrical signal.
    Type: Grant
    Filed: August 31, 2020
    Date of Patent: October 12, 2021
    Assignee: Cable Television Laboratories, Inc.
    Inventors: Mu Xu, Ruoyu Sun, Balkan Kecicioglu, Junwen Zhang, Haipeng Zhang, Zhensheng Jia, Luis Alberto Campos
  • Patent number: 11146338
    Abstract: Methods, systems, and devices for a decision directed multi-modulus searching algorithm are described. A receiver may receive an optical signal including a set of data symbols. The receiver may iteratively determine a set of centroids for demodulating the set of data symbols (e.g., as part of a training procedure). The centroids may be used to demodulate the set of data symbols according to a modulation constellation associated with the set of data symbols. The training procedure may include, for each data symbol of a subset of data symbols, assigning a centroid of the set of centroids to each data symbol and updating the set of centroids based on assigning the centroid to each data symbol. The receiver may demodulate the set of data symbols based on the updated set of centroids.
    Type: Grant
    Filed: July 12, 2019
    Date of Patent: October 12, 2021
    Assignee: Cable Television Laboratories, Inc.
    Inventors: Mu Xu, Zhensheng Jia
  • Patent number: 11108490
    Abstract: A digital receiver is configured to process a polarization multiplexed carrier from a communication network. The polarization multiplexed carrier includes a first polarization and a second polarization. The receiver includes a first lane for transporting a first input signal of the first polarization, a second lane for transporting a second input signal of the second polarization, a dynamic phase noise estimation unit disposed within the first lane and configured to determine a phase noise estimate of the first input signal, a first carrier phase recovery portion configured to remove carrier phase noise from the first polarization based on a combination of the first input signal and a function of the determined phase noise estimate, and a second carrier phase recovery portion configured to remove carrier phase noise from the second polarization based on a combination of the second input signal and the function of the determined phase noise estimate.
    Type: Grant
    Filed: January 9, 2020
    Date of Patent: August 31, 2021
    Assignee: Cable Television Laboratories, Inc.
    Inventors: Zhensheng Jia, Junwen Zhang, Mu Xu, Haipeng Zhang, Luis Alberto Campos, Curtis Dean Knittle
  • Patent number: 11108462
    Abstract: A skew compensation system for a coherent optical communication network includes a transmitter modulator having a first driver input for receiving a first signal from a first channel, a second driver input for receiving a second signal from a second channel, a source input for receiving a continuous wave source signal, and a modulation output in communication with an optical transport medium of the network. The system further includes a tunable delay line disposed between the second channel and the second driver input for inserting a pre-determined training sequence onto the second signal prior to the second driver input, and a processor for determining a skew amount between the second signal at the second driver input and the first signal at the first driver input, calculating a pre-compensation value corresponding to the skew amount, and reducing the skew amount at the modulation output according to the pre-compensation value.
    Type: Grant
    Filed: September 17, 2019
    Date of Patent: August 31, 2021
    Assignee: Cable Television Laboratories, Inc.
    Inventors: Mu Xu, Luis Alberto Campos, Haipeng Zhang, Junwen Zhang, Zhensheng Jia
  • Patent number: 11082143
    Abstract: A full duplex communication network includes an optical transmitter end having a first coherent optics transceiver, an optical receiver end having a second coherent optics transceiver, and an optical transport medium operably coupling the first coherent optics transceiver to the second coherent optics transceiver. The first coherent optics transceiver is configured to simultaneously transmit a downstream optical signal and receive an upstream optical signal. The second coherent optics transceiver is configured to simultaneously receive the downstream optical signal from the first coherent optics transceiver and transmit the upstream optical signal first coherent optics transceiver. At least one of the downstream optical signal and the upstream optical signal includes at least one coherent optical carrier and at least one non-coherent optical carrier.
    Type: Grant
    Filed: August 16, 2019
    Date of Patent: August 3, 2021
    Assignee: Cable Television Laboratories, Inc.
    Inventors: Zhensheng Jia, Luis Alberto Campos, Jing Wang, Mu Xu, Haipeng Zhang, Curtis Dean Knittle
  • Publication number: 20210194591
    Abstract: An injection locked transmitter for an optical communication network includes a master seed laser source input substantially confined to a single longitudinal mode, an input data stream, and a laser injected modulator including at least one slave laser having a resonator frequency that is injection locked to a frequency of the single longitudinal mode of the master seed laser source. The laser injected modulator is configured to receive the master seed laser source input and the input data stream, and output a laser modulated data stream.
    Type: Application
    Filed: March 8, 2021
    Publication date: June 24, 2021
    Inventors: Junwen Zhang, Zhensheng Jia, Luis Alberto Campos, Haipeng Zhang, Mu Xu, Jing Wang, Curtis Dean Knittle, Chuang Zhou
  • Publication number: 20210167857
    Abstract: A full duplex communication network includes an optical transmitter end having a first coherent optics transceiver, an optical receiver end having a second coherent optics transceiver, and an optical transport medium operably coupling the first coherent optics transceiver to the second coherent optics transceiver. The first coherent optics transceiver is configured to simultaneously transmit a downstream optical signal and receive an upstream optical signal. The second coherent optics transceiver is configured to simultaneously receive the downstream optical signal from the first coherent optics transceiver and transmit the upstream optical signal first coherent optics transceiver. At least one of the downstream optical signal and the upstream optical signal includes at least one coherent optical carrier and at least one non-coherent optical carrier.
    Type: Application
    Filed: February 8, 2021
    Publication date: June 3, 2021
    Inventors: Zhensheng Jia, Luis Alberto Campos, Jing Wang, Mu Xu, Haipeng Zhang, Curtis Dean Knittle
  • Patent number: 11025270
    Abstract: A method for differentiator-based compression of digital data includes (a) multiplying a tap-weight vector by an original data vector to generate a predicted signal, the original data vector comprising N sequential samples of an original signal, N being an integer greater than or equal to one, (b) using a subtraction module, subtracting the predicted signal from a sample of the original signal to obtain an error signal, (c) using a quantization module, quantizing the error signal to obtain a quantized error signal, and (d) updating the tap-weight vector according to changing statistical properties of the original signal.
    Type: Grant
    Filed: June 15, 2020
    Date of Patent: June 1, 2021
    Assignee: Cable Television Laboratories, Inc.
    Inventors: Mu Xu, Zhensheng Jia, Jing Wang, Luis Alberto Campos
  • Patent number: 10965393
    Abstract: An optical communication network includes a downstream optical transceiver. The downstream optical transceiver includes at least one coherent optical transmitter configured to transmit a downstream coherent dual-band optical signal having a left-side band portion, a right-side band portion, and a central optical carrier disposed within a guard band between the left-side band portion and the right-side band portion. The network further includes an optical transport medium configured to carry the downstream coherent dual-band optical signal from the downstream optical transceiver. The network further includes at least one modem device operably coupled to the optical transport medium and configured to receive the downstream coherent dual-band optical signal from the optical transport medium. The at least one modem device includes a downstream coherent optical receiver, and a first slave laser injection locked to a frequency of the central optical carrier.
    Type: Grant
    Filed: June 26, 2019
    Date of Patent: March 30, 2021
    Assignee: Cable Television Laboratories, Inc.
    Inventors: Mu Xu, Zhensheng Jia, Haipeng Zhang, Luis Alberto Campos
  • Patent number: 10958345
    Abstract: An echo cancellation method includes steps of (a) extracting phase-distortion estimates, (b) reconstructing an echo signal, (c) generating a clean signal, and (d) producing a primary signal. Step (a) includes extracting, from a first phase signal, a plurality of phase-distortion estimates, the first phase signal having been estimated from an echo-corrupted signal received at a first coherent transceiver of a coherent optical network. Step (b) includes reconstructing an echo signal from the plurality of phase-distortion estimates and a transmitted signal transmitted by the first coherent transceiver. Step (c) includes generating a clean signal as a difference between the reconstructed echo signal and the first phase signal. Step (d) includes producing a primary signal by mapping each of a plurality of clean-phase estimates of the clean signal to one of a plurality of constellation symbols associated with a modulation scheme of the primary signal.
    Type: Grant
    Filed: May 7, 2020
    Date of Patent: March 23, 2021
    Assignee: CABLE TELEVISION LABORATORIES, INC.
    Inventors: Mu Xu, Zhensheng Jia, Junwen Zhang, Haipeng Zhang, Luis Alberto Campos
  • Patent number: 10944478
    Abstract: An injection locked transmitter for an optical communication network includes a master seed laser source input substantially confined to a single longitudinal mode, an input data stream, and a laser injected modulator including at least one slave laser having a resonator frequency that is injection locked to a frequency of the single longitudinal mode of the master seed laser source. The laser injected modulator is configured to receive the master seed laser source input and the input data stream, and output a laser modulated data stream.
    Type: Grant
    Filed: December 11, 2019
    Date of Patent: March 9, 2021
    Assignee: Cable Television Laboratories, Inc.
    Inventors: Junwen Zhang, Zhensheng Jia, Luis Alberto Campos, Haipeng Zhang, Mu Xu, Jing Wang, Curtis Dean Knittie, Chuang Zhou
  • Publication number: 20210050920
    Abstract: A full duplex communication network includes an optical transmitter end having a first coherent optics transceiver, an optical receiver end having a second coherent optics transceiver, and an optical transport medium operably coupling the first coherent optics transceiver to the second coherent optics transceiver. The first coherent optics transceiver is configured to (i) transmit a downstream optical signal at a first wavelength, and (ii) simultaneously receive an upstream optical signal at a second wavelength. The second coherent optics transceiver is configured to (i) receive the downstream optical signal, and (ii) simultaneously transmit the upstream optical signal. The first wavelength has a first center frequency separated from a second center frequency of the second wavelength.
    Type: Application
    Filed: August 3, 2020
    Publication date: February 18, 2021
    Inventors: Zhensheng Jia, Luis Alberto Campos, Jing Wang, Mu Xu, Haipeng Zhang, Curtis Dean Knittle
  • Patent number: 10917175
    Abstract: A full duplex communication network includes an optical transmitter end having a first coherent optics transceiver, an optical receiver end having a second coherent optics transceiver, and an optical transport medium operably coupling the first coherent optics transceiver to the second coherent optics transceiver. The first coherent optics transceiver is configured to simultaneously transmit a downstream optical signal and receive an upstream optical signal. The second coherent optics transceiver is configured to simultaneously receive the downstream optical signal from the first coherent optics transceiver and transmit the upstream optical signal first coherent optics transceiver. At least one of the downstream optical signal and the upstream optical signal includes at least one coherent optical carrier and at least one non-coherent optical carrier.
    Type: Grant
    Filed: November 6, 2019
    Date of Patent: February 9, 2021
    Assignee: Cable Television Laboratories, Inc.
    Inventors: Zhensheng Jia, Luis Alberto Campos, Jing Wang, Mu Xu, Haipeng Zhang, Curtis Dean Knittle
  • Patent number: 10897310
    Abstract: An optical line terminal includes an optical comb generator, N downlink channels Dk, and N uplink-photodetectors PDk. The optical comb generator is configured to generate a carrier signal having an optical-frequency-comb spectrum and including N optical tones Tk and N optical tones Rk, k={1, 2, . . . , N}. Each of the N downlink channels Dk is optically coupled to the optical comb generator and is configured to generate a respective downlink signal DSk that includes optical tone Tk modulated by downlink data. Each of the N uplink-photodetectors PDk is configured to receive a respective one of a plurality of modulated uplink signals USk, having optical tone Rk as a carrier signal.
    Type: Grant
    Filed: June 26, 2019
    Date of Patent: January 19, 2021
    Assignee: CABLE TELEVISION LABORATORIES, INC.
    Inventors: Haipeng Zhang, Zhensheng Jia, Mu Xu
  • Patent number: 10873493
    Abstract: A carrier-phase recovery method includes: (i) applying a first carrier-phase recovery algorithm to complex-valued symbols of a signal received by a product detector, yielding coarse phase-estimates, the signal being modulated per an M-QAM scheme; (ii) modelling the coarse phase-estimates as a weighted sum of M probability-density functions of an M-component mixture model; (iii) optimizing the M probability-density functions with an expectation-maximization algorithm to yield M optimized probability-density functions; (iv) mapping, based on the M optimized probability-density functions, the coarse phase-estimates to one of M symbols corresponding to the QAM scheme, each coarse phase-estimate mapped to a same symbol belonging to a same one of M clusters; (v) applying a second carrier-phase recovery algorithm to each of the M clusters to generate refined phase-estimates each corresponding to a respective coarse phase-estimate; and (vi) mapping, based on the M optimized probability-density functions, each refined
    Type: Grant
    Filed: May 14, 2019
    Date of Patent: December 22, 2020
    Assignee: CABLE TELEVISION LABORATORIES, INC.
    Inventors: Mu Xu, Zhensheng Jia
  • Publication number: 20200389674
    Abstract: An optical network includes a transmitting portion configured to (i) encode an input digitized sequence of data samples into a quantized sequence of data samples having a first number of digits per sample, (ii) map the quantized sequence of data samples into a compressed sequence of data samples having a second number of digits per sample, the second number being lower than the first number, and (iii) modulate the compressed sequence of data samples and transmit the modulated sequence over a digital optical link. The optical network further includes a receiving portion configured to (i) receive and demodulate the modulated sequence from the digital optical link, (ii) map the demodulated sequence from the second number of digits per sample into a decompressed sequence having the first number of digits per sample, and (iii) decode the decompressed sequence.
    Type: Application
    Filed: August 24, 2020
    Publication date: December 10, 2020
    Inventors: Zhensheng Jia, Luis Alberto Campos, Mu Xu, Jing Wang
  • Publication number: 20200336211
    Abstract: An optical full-field transmitter for an optical communications network includes a primary laser source configured to provide a narrow spectral linewidth for a primary laser signal, and a first intensity modulator in communication with a first amplitude data source. The first intensity modulator is configured to output a first amplitude-modulated optical signal from the laser signal. The transmitter further includes a first phase modulator in communication with a first phase data source and the first amplitude-modulated optical signal. The first phase modulator is configured to output a first two-stage full-field optical signal. The primary laser source has a structure based on a III-V compound semiconductor.
    Type: Application
    Filed: April 22, 2020
    Publication date: October 22, 2020
    Inventors: HAIPENG ZHANG, JUNWEN ZHANG, MU XU, ZHENSHENG JIA, LUIS ALBERTO CAMPOS
  • Publication number: 20200295837
    Abstract: An injection locked transmitter for an optical communication network includes a master seed laser source input substantially confined to a single longitudinal mode, an input data stream, and a laser injected modulator including at least one slave laser having a resonator frequency that is injection locked to a frequency of the single longitudinal mode of the master seed laser source. The laser injected modulator is configured to receive the master seed laser source input and the input data stream, and output a laser modulated data stream.
    Type: Application
    Filed: December 11, 2019
    Publication date: September 17, 2020
    Inventors: Junwen Zhang, Zhensheng Jia, Luis Alberto Campos, Haipeng Zhang, Mu Xu, Jing Wang, Curtis Dean Knittle, Chuang Zhou