Patents by Inventor Hisayuki Ojima
Hisayuki Ojima 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: 20200169324Abstract: An optical transmission apparatus includes a detecting circuit configured to detect one or more empty slots in which a data signal is not accommodated in a plurality of slots included in a frame, a frame processing circuit configured to reduce size of the frame by deleting the one or more empty slots from the frame based on a detection result of the one or more empty slots and closing up gaps between remaining slots in the plurality of slots, and an optical modulation processing circuit configured to carry out multi-level modulation of the frame at a bit rate according to size of the frame after reduction.Type: ApplicationFiled: November 22, 2019Publication date: May 28, 2020Applicant: FUJITSU LIMITEDInventors: Kunihiko YANAGIKUIDA, Shota Shinohara, Hisayuki Ojima, Toshihiro Suzuki, Taketo Endo, Hayato Furukawa
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Publication number: 20190149258Abstract: A transmission and reception apparatus, includes a processor and a processing device coupled to the processor, wherein the processor is configured to detect insertion of a pluggable module, issue, when the insertion of the pluggable module is detected, an instruction to the processing device to generate a first test signal to be supplied to the pluggable module, extract an alternating current component from a first monitoring result of the first test signal by the pluggable module and acquiring pulse width information at a plurality of phase points, and set a phase point determined based on the pulse width information as an optimum phase value to the processing device.Type: ApplicationFiled: November 15, 2018Publication date: May 16, 2019Applicant: FUJITSU LIMITEDInventors: Hirofumi Araki, Hisayuki Ojima, Yasushi YOSHINO, Satoru Saitoh, KAZUYA IKEDA, TAICHI ISHIKAWA
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Patent number: 9768906Abstract: An optical transmission apparatus includes: a plurality of optical transmitters configured to transmit optical signals having variable wavelengths, respectively; a multiplexer configured to wavelength-multiplex the optical signals transmitted from the plurality of optical transmitters in a transmission band of an optical device through which the optical signals is transmitted; and a controller configured to control, in response to nonexistence of an optical signal having a second wavelength adjacent to a first wavelength closest to an outer edge of the transmission band in the optical signals, an optical transmitter corresponding to the first wavelength so as to shift the first wavelength in a direction toward the second wavelength.Type: GrantFiled: January 20, 2016Date of Patent: September 19, 2017Assignee: FUJITSU LIMITEDInventors: Hisayuki Ojima, Taku Saito
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Patent number: 9479249Abstract: An optical transmission system includes a transmitting device and a receiving device, wherein the transmitting device includes a modulating unit that changes a frequency of an optical signal, and the receiving device includes a filtering unit that passes an optical signal in a predetermined frequency band; a measuring unit that measures an intensity of an optical signal that passes through the filtering unit; a detecting unit that detects a center wavelength of the optical signal in accordance with an intensity of the optical signal that is measured when a frequency of the optical signal is changed in a state of a passed band that corresponds to the optical signal; and an output unit that outputs information that indicates the detected center wavelength to the transmitting device, wherein the transmitting device controls a wavelength of the optical signal in accordance with the information from the receiving device.Type: GrantFiled: August 5, 2015Date of Patent: October 25, 2016Assignee: FUJITSU LIMITEDInventors: Taketo Endo, Tomohiro Kaneoka, Hisayuki Ojima, Shoichi Murakami
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Publication number: 20160261362Abstract: An optical transmission apparatus includes: a plurality of optical transmitters configured to transmit optical signals having variable wavelengths, respectively; a multiplexer configured to wavelength-multiplex the optical signals transmitted from the plurality of optical transmitters in a transmission band of an optical device through which the optical signals is transmitted; and a controller configured to control, in response to nonexistence of an optical signal having a second wavelength adjacent to a first wavelength closest to an outer edge of the transmission band in the optical signals, an optical transmitter corresponding to the first wavelength so as to shift the first wavelength in a direction toward the second wavelength.Type: ApplicationFiled: January 20, 2016Publication date: September 8, 2016Applicant: FUJITSU LIMITEDInventors: Hisayuki Ojima, Taku Saito
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Publication number: 20160065305Abstract: An optical transmission system includes a transmitting device and a receiving device, wherein the transmitting device includes a modulating unit that changes a frequency of an optical signal, and the receiving device includes a filtering unit that passes an optical signal in a predetermined frequency band; a measuring unit that measures an intensity of an optical signal that passes through the filtering unit; a detecting unit that detects a center wavelength of the optical signal in accordance with an intensity of the optical signal that is measured when a frequency of the optical signal is changed in a state of a passed band that corresponds to the optical signal; and an output unit that outputs information that indicates the detected center wavelength to the transmitting device, wherein the transmitting device controls a wavelength of the optical signal in accordance with the information from the receiving device.Type: ApplicationFiled: August 5, 2015Publication date: March 3, 2016Applicants: FUJITSU LIMITED, FUJITSU TELECOM NETWORKS LIMITEDInventors: Taketo ENDO, Tomohiro Kaneoka, Hisayuki Ojima, Shoichi Murakami
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Patent number: 9191119Abstract: An optical transmission apparatus receives an optical signal of an optical wavelength. The optical transmission apparatus has a variable wavelength filter, a neighboring frequency detection unit, and an ADC/DSP. The variable wavelength filter detects a neighboring of another optical transmission apparatus that receives an optical signal of a wavelength different from the wavelength. The neighboring frequency detection unit determines whether or not a second frequency supported by the another optical transmission apparatus where a neighboring has been detected by the variable wavelength filter is different from a first frequency supported by the optical transmission apparatus. The ADC/DSP changes a parameter for removing a phase noise from the optical signal of the wavelength according to a difference between the first frequency and the second frequency when it is determined that the second frequency is different from the first frequency.Type: GrantFiled: March 28, 2014Date of Patent: November 17, 2015Assignee: FUJITSU LIMITEDInventors: Hisayuki Ojima, Hiroshi Iizuka
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Publication number: 20140314427Abstract: An optical transmission apparatus receives an optical signal of an optical wavelength. The optical transmission apparatus has a variable wavelength filter, a neighboring frequency detection unit, and an ADC/DSP. The variable wavelength filter detects a neighboring of another optical transmission apparatus that receives an optical signal of a wavelength different from the wavelength. The neighboring frequency detection unit determines whether or not a second frequency supported by the another optical transmission apparatus where a neighboring has been detected by the variable wavelength filter is different from a first frequency supported by the optical transmission apparatus. The ADC/DSP changes a parameter for removing a phase noise from the optical signal of the wavelength according to a difference between the first frequency and the second frequency when it is determined that the second frequency is different from the first frequency.Type: ApplicationFiled: March 28, 2014Publication date: October 23, 2014Applicant: FUJITSU LIMITEDInventors: Hisayuki OJIMA, Hiroshi IIZUKA
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Patent number: 8488622Abstract: A jitter control apparatus used in a multiplexing apparatus multiplexing a plurality of signals by asynchronous mapping, includes: a detection unit configured to detect a frequency of timing compensation processes in the asynchronous mapping for each of the plurality of signals; and a selection unit configured to select, on basis of a detection result by the detection unit, a clock signal to be used as a carrier clock for the plurality of signals, from a plurality of clock signals including clock signals extracted from at least one of the plurality of signals.Type: GrantFiled: December 2, 2009Date of Patent: July 16, 2013Assignee: Fujitsu LimitedInventors: Yuichiro Sakamoto, Hisayuki Ojima
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Patent number: 8139947Abstract: An optical transmission apparatus includes a first transceiver unit coupled to a first node, a second transceiver unit coupled to a second node, an electrical signal processing unit provided between the transceiver units, a first transmission clock generating unit configured to generate a clock used by the second transceiver unit based on a clock of a signal arriving through the first node, a second transmission clock generating unit configured to generate a clock used by the first transceiver unit based on a clock of a signal arriving through the second node, a selector configured to select an output clock of the first transmission clock generating unit at a time of optical input interruption at the second node, and a frequency dividing unit configured to produce a frequency-divided clock obtained by dividing frequency of the output clock selected by the selector for provision to the second transmission clock generating unit.Type: GrantFiled: February 12, 2009Date of Patent: March 20, 2012Assignee: Fujitsu LimitedInventor: Hisayuki Ojima
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Patent number: 7711218Abstract: The optical reception apparatus of the invention branches into two an RZ-DQPSK optical signal input from an optical transmission path via an optical amplifier, respectively sends this to delay interferometers and photoelectric converters on a pair of arms, separately detects a number of generated errors for the signals propagating through the arms in an error-number detection circuit, obtains a difference in the respective number of generated errors in an error-number detector, and controls phase shift in the delay interferometers so that the difference is within a preset tolerance. By so doing, it is possible to realize excellent reception performance by suppressing the occurrence of the burst error.Type: GrantFiled: April 30, 2008Date of Patent: May 4, 2010Assignee: Fujitsu LimitedInventors: Hisayuki Ojima, Katsumi Fukumitsu
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Publication number: 20100074386Abstract: A jitter control apparatus used in a multiplexing apparatus multiplexing a plurality of signals by asynchronous mapping, includes: a detection unit configured to detect a frequency of timing compensation processes in the asynchronous mapping for each of the plurality of signals; and a selection unit configured to select, on basis of a detection result by the detection unit, a clock signal to be used as a carrier clock for the plurality of signals, from a plurality of clock signals including clock signals extracted from at least one of the plurality of signals.Type: ApplicationFiled: December 2, 2009Publication date: March 25, 2010Applicant: FUJITSU LIMITEDInventors: Yuichiro SAKAMOTO, Hisayuki Ojima
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Publication number: 20090297161Abstract: An optical transmission apparatus includes a first transceiver unit coupled to a first node, a second transceiver unit coupled to a second node, an electrical signal processing unit provided between the transceiver units, a first transmission clock generating unit configured to generate a clock used by the second transceiver unit based on a clock of a signal arriving through the first node, a second transmission clock generating unit configured to generate a clock used by the first transceiver unit based on a clock of a signal arriving through the second node, a selector configured to select an output clock of the first transmission clock generating unit at a time of optical input interruption at the second node, and a frequency dividing unit configured to produce a frequency-divided clock obtained by dividing frequency of the output clock selected by the selector for provision to the second transmission clock generating unit.Type: ApplicationFiled: February 12, 2009Publication date: December 3, 2009Applicant: FUJITSU LIMITEDInventor: Hisayuki Ojima
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Publication number: 20090028580Abstract: The optical reception apparatus of the invention branches into two an RZ-DQPSK optical signal input from an optical transmission path via an optical amplifier, respectively sends this to delay interferometers and photoelectric converters on a pair of arms, separately detects a number of generated errors for the signals propagating through the arms in an error-number detection circuit, obtains a difference in the respective number of generated errors in an error-number detector, and controls phase shift in the delay interferometers so that the difference is within a preset tolerance. By so doing, it is possible to realize excellent reception performance by suppressing the occurrence of the burst error.Type: ApplicationFiled: April 30, 2008Publication date: January 29, 2009Applicant: Fujitsu LimitedInventors: Hisayuki Ojima, Katsumi Fukumitsu
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Patent number: 7466478Abstract: An optical-level control apparatus includes a plurality of variable optical attenuators each used for attenuating an input optical signal included in a wavelength division multiplexing signal as a component having a specific wavelength by applying a variable attenuation quantity, a plurality of control units each used for executing automatic control for automatically controlling the attenuation quantity in order to adjust the optical level of an optical signal output by a corresponding one of the variable optical attenuators to a target level in an ordinary normal state of the input optical signal, and a detection unit for detecting a loss of light failure of an optical signal input to each of the variable optical attenuators and detecting disappearance of the loss of light failure.Type: GrantFiled: March 15, 2005Date of Patent: December 16, 2008Assignee: Fujitsu LimitedInventors: Takuji Maeda, Haruki Tanaka, Hisayuki Ojima, Hiroaki Tomofuji, Hideaki Sugiya, Koji Batou
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Patent number: 7430372Abstract: An optical transmission system is provided which is capable of booting the system by using an ASE (Amplified Spontaneous Emission) light in a manner to provide high quality. A pre-amplifier receives noise light and does gain setting in an amplifier booting mode and receives an optical signal and to amplify the received signal in a working mode. A variable dispersion compensator is placed in a preceding-stage of the pre-amplifier and makes compensation of dispersion of a wavelength occurring when an optical signal propagates through an optical fiber in a variable manner.Type: GrantFiled: June 1, 2005Date of Patent: September 30, 2008Assignee: Fujitsu LimitedInventors: Mamoru Suematsu, Akira Yamamoto, Haruki Tanaka, Hideaki Sugiya, Yuki Murakami, Hisayuki Ojima
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Publication number: 20070047960Abstract: A method for an intermediate node to control a level of a signal included in a wavelength-multiplexed signal and transmitted from a source node to a destination node via the intermediate node, includes: detecting a level of the signal; identifying a position of the intermediate node with respect to the source node; determining a control time based on the position; controlling, when the control time has elapsed from the detecting, a level of the signal based on the level detected at the detecting.Type: ApplicationFiled: February 8, 2006Publication date: March 1, 2007Inventors: Takeshi Noma, Akira Yamamoto, Katsumi Sugawa, Hisayuki Ojima, Haruki Tanaka, Hideaki Sugiya, Koji Bato
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Publication number: 20060188262Abstract: An optical transmission system is provided which is capable of booting the system by using an ASE (Amplified Spontaneous Emission) light in a manner to provide high quality. A pre-amplifier receives noise light and does gain setting in an amplifier booting mode and receives an optical signal and to amplify the received signal in a working mode. A variable dispersion compensator is placed in a preceding-stage of the pre-amplifier and makes compensation of dispersion of a wavelength occurring when an optical signal propagates through an optical fiber in a variable manner.Type: ApplicationFiled: June 1, 2005Publication date: August 24, 2006Applicant: FUJITSU LIMITEDInventors: Mamoru Suematsu, Akira Yamamoto, Haruki Tanaka, Hideaki Sugiya, Yuki Murakami, Hisayuki Ojima
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Publication number: 20050168806Abstract: An optical-level control apparatus includes a plurality of variable optical attenuators each used for attenuating an input optical signal included in a wavelength division multiplexing signal as a component having a specific wavelength by applying a variable attenuation quantity, a plurality of control units each used for executing automatic control for automatically controlling the attenuation quantity in order to adjust the optical level of an optical signal output by a corresponding one of the variable optical attenuators to a target level in an ordinary normal state of the input optical signal, and a detection unit for detecting a loss of light failure of an optical signal input to each of the variable optical attenuators and detecting disappearance of the loss of light failure.Type: ApplicationFiled: March 15, 2005Publication date: August 4, 2005Applicant: Fujitsu LimitedInventors: Takuji Maeda, Haruki Tanaka, Hisayuki Ojima, Hiroaki Tomofuji, Hideaki Sugiya, Koji Batou
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Patent number: 5608343Abstract: A circuit changes the timing for reading data by varying bias potential applied to a clock signal used to read the data. The circuit has a comparator for comparing an external clock signal with a reference voltage that provides a logic decision level and generating an internal clock signal, and a logic circuit for fetching input data in synchronization with the internal clock signal. The comparator has a bias changer. The bias changer applies DC bias potential to the external clock signal to the comparator, to change the phase of the internal clock signal.Type: GrantFiled: April 27, 1995Date of Patent: March 4, 1997Assignee: Fujitsu LimitedInventors: Hisayuki Ojima, Hiroshi Kuwahara