Patents by Inventor GUOXIU HUANG
GUOXIU HUANG 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).
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Publication number: 20240137127Abstract: An optical transmitter includes a signal processor and transmission circuit. The signal processor modulates a first signal to generate a first modulated signal, determines a modulo amplitude that is larger than an amplitude of the first modulated signal, inserts a second modulated signal into the first modulated signal to generate a transmission signal, corrects a symbol of the transmission signal by using an amplitude of one or a plurality of previous symbols to generate a pre-equalized signal, and performs modulo calculation based on the modulo amplitude on the pre-equalized signal. The transmission circuit generates a modulated optical signal based on an output signal of the signal processor and transmits the modulated optical signal to a reception node. An amplitude of the second modulated signal is equal to the modulo amplitude.Type: ApplicationFiled: July 17, 2023Publication date: April 25, 2024Applicant: Fujitsu LimitedInventors: GUOXIU HUANG, Hisao NAKASHIMA
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Patent number: 11956018Abstract: A quantizer includes: a clipper configured to clip a portion exceeding a quantization range of a sample value sampled at a predetermined rate; and a noise shaper configured to determine a plurality of candidates for a quantization level based on the clipped sample value, and outputs, as a quantization value, a value obtained by adding a minimum noise in which a noise in a low-frequency region is minimum among noises generated in each candidate to the sample value before clipping.Type: GrantFiled: August 31, 2022Date of Patent: April 9, 2024Assignee: FUJITSU LIMITEDInventors: Guoxiu Huang, Hisao Nakashima
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Publication number: 20230188217Abstract: A quantizer includes: a clipper configured to clip a portion exceeding a quantization range of a sample value sampled at a predetermined rate; and a noise shaper configured to determine a plurality of candidates for a quantization level based on the clipped sample value, and outputs, as a quantization value, a value obtained by adding a minimum noise in which a noise in a low-frequency region is minimum among noises generated in each candidate to the sample value before clipping.Type: ApplicationFiled: August 31, 2022Publication date: June 15, 2023Applicant: FUJITSU LIMITEDInventors: GUOXIU HUANG, Hisao Nakashima
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Patent number: 11460750Abstract: An optical modulator includes: a Mach-Zehnder modulator; and a processor that controls a bias of the Mach-Zehnder modulator. The Mach-Zehnder modulator includes first and second Mach-Zehnder interferometers that are respectively formed on first and second optical paths, a phase shifter that adjusts a phase difference between the first optical path and the second optical path. The processor outputs a first bias signal for controlling an operation point of the first Mach-Zehnder interferometer, a second bias signal for controlling an operation point of the second Mach-Zehnder interferometer, and a third bias signal for controlling a phase-shift amount of the phase shifter, a low-frequency signal being superimposed on the third bias signal. The processor controls the first through third bias signals based on a frequency component of the low-frequency signal that is included in the optical signal output from the Mach-Zehnder modulator.Type: GrantFiled: December 10, 2020Date of Patent: October 4, 2022Assignee: FUJITSU LIMITEDInventors: Guoxiu Huang, Hisao Nakashima
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Patent number: 11303483Abstract: A transmission device includes an imparter configured to impart redundant data to the beginning of each of a plurality of data blocks divided from a data signal, a plurality of THP operators configured to parallelly precode the plurality of data blocks to which the redundant data is imparted, a transmitter configured to sequentially transmit the plurality of data blocks precoded by the plurality of THP operators and the redundant data imparted to each of the plurality of data blocks to a transmission line according to an arrangement order in the data signal, wherein the plurality of THP operators feed back a plurality of pieces of the redundant data to the plurality of data blocks, respectively.Type: GrantFiled: July 7, 2021Date of Patent: April 12, 2022Assignee: FUJITSU LIMITEDInventors: Guoxiu Huang, Hisao Nakashima
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Publication number: 20210223658Abstract: An optical modulator includes: a Mach-Zehnder modulator; and a processor that controls a bias of the Mach-Zehnder modulator. The Mach-Zehnder modulator includes first and second Mach-Zehnder interferometers that are respectively formed on first and second optical paths, a phase shifter that adjusts a phase difference between the first optical path and the second optical path. The processor outputs a first bias signal for controlling an operation point of the first Mach-Zehnder interferometer, a second bias signal for controlling an operation point of the second Mach-Zehnder interferometer, and a third bias signal for controlling a phase-shift amount of the phase shifter, a low-frequency signal being superimposed on the third bias signal. The processor controls the first through third bias signals based on a frequency component of the low-frequency signal that is included in the optical signal output from the Mach-Zehnder modulator.Type: ApplicationFiled: December 10, 2020Publication date: July 22, 2021Applicant: FUJITSU LIMITEDInventors: GUOXIU HUANG, Hisao Nakashima
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Patent number: 10425166Abstract: An optical transmitter includes, an optical modulator that multilevel-modulates light outputted from a light source, and a processor that outputs a first drive voltage for driving the optical modulator according to an amplitude component when transmission data is symbol-mapped and a second drive voltage for driving the optical modulator according to a phase component when the transmission data is symbol-mapped. A phase shift of phase modulation by the second drive voltage outputted from the processor is greater than 0 and less than ?/2.Type: GrantFiled: July 9, 2018Date of Patent: September 24, 2019Assignee: FUJITSU LIMITEDInventors: Tomohiro Yamauchi, Tomofumi Oyama, Takahito Tanimura, Guoxiu Huang, Takeshi Hoshida
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Patent number: 10396900Abstract: A method of controlling a transmission signal, includes transmitting a training signal including four polarization states having a given relation; and performing rotation control and transmission power level control of a polarization component of a data signal, based on a rotation control matrix for a polarization state and an inverse-operation control matrix for a power level imbalance, which are estimated from Stokes parameters related to input power level present on a Poincare sphere acquired from the training signal and Stokes parameters related to output power level present on the Poincare sphere.Type: GrantFiled: March 16, 2018Date of Patent: August 27, 2019Assignee: FUJITSU LIMITEDInventors: Guoxiu Huang, Setsuo Yoshida, Takeshi Hoshida, Hisao Nakashima, Shoichiro Oda
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Patent number: 10341027Abstract: An optical transmitter includes, a processor that receives an input data signal from an outside and performs rotation processing for periodically or repeatedly rotating a polarization state or phase of the optical output signal upon the input data signal, an optical modulator that modulates light transmitted from a light source based on the input data signal, a digital-to-analog converter that converts an output of the processor into an analog electric signal, a driving circuit that amplifies an output of the digital-to-analog converter and drives the optical modulator, and a monitoring control circuit that monitors an optical output signal output from the optical modulator and adjusts at least one of an output of the digital-to-analog converter and a gain of the driving circuit based on a result of monitoring of the optical output signal.Type: GrantFiled: July 15, 2018Date of Patent: July 2, 2019Assignee: FUJITSU LIMITEDInventors: Guoxiu Huang, Hisao Nakashima, Yuichi Akiyama, Takeshi Hoshida
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Patent number: 10230463Abstract: A transmitter generates a frequency-modulated CW light so as to transmit it to a path. A receiver receives the CW light that has passed through passband filters included in the path. The receiver includes a processor. The processor measures an optical power of the received CW light every time a center frequency of the CW light is changed and transmitted by the transmitter. The processor calculates transmission characteristics of the CW light that has passed through the passband filters, on the basis of an average value of the optical power that corresponds to a center frequency of the CW light and on the basis of an amplitude component that indicates an amount of change in the optical power, the average value and the amplitude component being obtained as a result of the measurement.Type: GrantFiled: August 3, 2016Date of Patent: March 12, 2019Assignee: FUJITSU LIMITEDInventors: Guoxiu Huang, Yasuhiko Aoki, Shoichiro Oda, Zhenning Tao, Setsuo Yoshida, Kyosuke Sone
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Publication number: 20190028205Abstract: An optical transmitter includes, a processor that receives an input data signal from an outside and performs rotation processing for periodically or repeatedly rotating a polarization state or phase of the optical output signal upon the input data signal, an optical modulator that modulates light transmitted from a light source based on the input data signal, a digital-to-analog converter that converts an output of the processor into an analog electric signal, a driving circuit that amplifies an output of the digital-to-analog converter and drives the optical modulator, and a monitoring control circuit that monitors an optical output signal output from the optical modulator and adjusts at least one of an output of the digital-to-analog converter and a gain of the driving circuit based on a result of monitoring of the optical output signal.Type: ApplicationFiled: July 15, 2018Publication date: January 24, 2019Applicant: FUJITSU LIMITEDInventors: GUOXIU HUANG, Hisao Nakashima, YUICHI AKIYAMA, Takeshi Hoshida
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Publication number: 20190020418Abstract: An optical transmitter includes, an optical modulator that multilevel-modulates light outputted from a light source, and a processor that outputs a first drive voltage for driving the optical modulator according to an amplitude component when transmission data is symbol-mapped and a second drive voltage for driving the optical modulator according to a phase component when the transmission data is symbol-mapped. A phase shift of phase modulation by the second drive voltage outputted from the processor is greater than 0 and less than ?/2.Type: ApplicationFiled: July 9, 2018Publication date: January 17, 2019Applicant: FUJITSU LIMITEDInventors: Tomohiro YAMAUCHI, Tomofumi Oyama, Takahito Tanimura, GUOXIU HUANG, Takeshi Hoshida
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Publication number: 20180278336Abstract: A method of controlling a transmission signal, includes transmitting a training signal including four polarization states having a given relation; and performing rotation control and transmission power level control of a polarization component of a data signal, based on a rotation control matrix for a polarization state and an inverse-operation control matrix for a power level imbalance, which are estimated from Stokes parameters related to input power level present on a Poincare sphere acquired from the training signal and Stokes parameters related to output power level present on the Poincare sphere.Type: ApplicationFiled: March 16, 2018Publication date: September 27, 2018Applicant: FUJITSU LIMITEDInventors: GUOXIU HUANG, Setsuo Yoshida, Takeshi Hoshida, Hisao Nakashima, Shoichiro Oda
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Patent number: 9887774Abstract: A transmission characteristics monitoring device monitors transmission characteristics of an optical transmission path between nodes. The device detects an average power of the frequency modulated optical signal and a slope of the transmission characteristics; generates a slope function that represents a slope of the transmission characteristics between first and second frequencies; generates a corrected power value by adding an integral of the slope function to a first power measurement value detected at the first frequency; calculates the transmission characteristics at the second frequency based on a second power measurement value detected at the second frequency when the difference between the second power measurement value and the corrected power value is smaller than a specified threshold; and calculates the transmission characteristics at the second frequency based on the corrected power value when the difference is greater than the specified threshold.Type: GrantFiled: March 13, 2017Date of Patent: February 6, 2018Assignee: FUJITSU LIMITEDInventors: Guoxiu Huang, Yasuhiko Aoki, Shoichiro Oda, Setsuo Yoshida
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Patent number: 9838148Abstract: An optical receiver includes: a tunable filter configured to partially transmit a wavelength-multiplexed optical-signal including a first optical-signal having a first wavelength, a second optical-signal having a second wavelength, and a third optical-signal having a third wavelength, with a frequency-modulated signal superimposed on each of the first to third optical-signals; a photo detector configured to detect an optical-power of the wavelength-multiplexed optical-signal transmitted through the tunable filter; and a superimposed signal detector configured to detect the frequency-modulated signal superimposed on the first optical-signal, based on an amplitude-modulated signal according to a variation in the optical-power on a first filter setting where both of the first optical-signal and the second optical-signal transmit through the tunable filter, and an amplitude-modulated signal according to a variation in the optical-power on a second filter setting where both of the first optical-signal and the thirType: GrantFiled: April 11, 2016Date of Patent: December 5, 2017Assignee: FUJITSU LIMITEDInventors: Goji Nakagawa, Tomohiro Yamauchi, Guoxiu Huang, Setsuo Yoshida, Shoichiro Oda, Kyosuke Sone, Yasuhiko Aoki
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Publication number: 20170279528Abstract: A transmission characteristics monitoring device monitors transmission characteristics of an optical transmission path between nodes. The device detects an average power of the frequency modulated optical signal and a slope of the transmission characteristics; generates a slope function that represents a slope of the transmission characteristics between first and second frequencies; generates a corrected power value by adding an integral of the slope function to a first power measurement value detected at the first frequency; calculates the transmission characteristics at the second frequency based on a second power measurement value detected at the second frequency when the difference between the second power measurement value and the corrected power value is smaller than a specified threshold; and calculates the transmission characteristics at the second frequency based on the corrected power value when the difference is greater than the specified threshold.Type: ApplicationFiled: March 13, 2017Publication date: September 28, 2017Applicant: FUJITSU LIMITEDInventors: GUOXIU HUANG, Yasuhiko Aoki, Shoichiro Oda, Setsuo Yoshida
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Publication number: 20170047993Abstract: A transmitter generates a frequency-modulated CW light so as to transmit it to a path. A receiver receives the CW light that has passed through passband filters included in the path. The receiver includes a processor. The processor measures an optical power of the received CW light every time a center frequency of the CW light is changed and transmitted by the transmitter. The processor calculates transmission characteristics of the CW light that has passed through the passband filters, on the basis of an average value of the optical power that corresponds to a center frequency of the CW light and on the basis of an amplitude component that indicates an amount of change in the optical power, the average value and the amplitude component being obtained as a result of the measurement.Type: ApplicationFiled: August 3, 2016Publication date: February 16, 2017Applicant: FUJITSU LIMITEDInventors: GUOXIU HUANG, Yasuhiko Aoki, Shoichiro Oda, Zhenning Tao, Setsuo Yoshida, Kyosuke Sone
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Publication number: 20160337070Abstract: An optical receiver includes: a tunable filter configured to partially transmit a wavelength-multiplexed optical-signal including a first optical-signal having a first wavelength, a second optical-signal having a second wavelength, and a third optical-signal having a third wavelength, with a frequency-modulated signal superimposed on each of the first to third optical-signals; a photo detector configured to detect an optical-power of the wavelength-multiplexed optical-signal transmitted through the tunable filter; and a superimposed signal detector configured to detect the frequency-modulated signal superimposed on the first optical-signal, based on an amplitude-modulated signal according to a variation in the optical-power on a first filter setting where both of the first optical-signal and the second optical-signal transmit through the tunable filter, and an amplitude-modulated signal according to a variation in the optical-power on a second filter setting where both of the first optical-signal and the thirType: ApplicationFiled: April 11, 2016Publication date: November 17, 2016Applicant: FUJITSU LIMITEDInventors: GOJI NAKAGAWA, Tomohiro YAMAUCHI, GUOXIU HUANG, Setsuo Yoshida, Shoichiro Oda, Kyosuke Sone, Yasuhiko Aoki
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Publication number: 20160337039Abstract: An optical transmitting device includes: an optical modulator configured to modulate light output from a light source with a drive signal generated by controlling a frequency of a first signal based on a second signal; and an amplitude controller configured to control amplitude of the first signal based on a control signal, wherein signal light modulated by the optical modulator is transmitted to an optical receiving device.Type: ApplicationFiled: April 22, 2016Publication date: November 17, 2016Applicant: FUJITSU LIMITEDInventors: GUOXIU HUANG, Yasuhiko Aoki, Shoichiro Oda