Patents by Inventor Masaji Noguchi
Masaji Noguchi 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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Patent number: 8274733Abstract: A semiconductor optical amplification module that can suppress ringing without increasing power consumption or circuit size or inhibiting high-speed operation. A semiconductor optical amplifier outputs an optical signal inputted according to driving current outputted from a drive circuit. A diode is connected in parallel with the semiconductor optical amplifier. As a result, it becomes possible to suppress ringing without connecting a large resistor to the drive circuit.Type: GrantFiled: February 5, 2008Date of Patent: September 25, 2012Assignee: Fujitsu LimitedInventor: Masaji Noguchi
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Patent number: 8179593Abstract: An optical-switch drive circuit including a driver unit that generates, in response to a control signal, an on/off signal for driving a semiconductor optical amplifier gate switch, and a buffer unit having a high input impedance and connected between an output terminal outputting the on/off signal and the semiconductor optical amplifier gate switch. In the optical-switch drive circuit the buffer unit may include a high-resistance voltage divider that is connected with the output terminal, and an operational amplifier that buffers, and provides to the semiconductor optical amplifier gate switch, a divided voltage of the voltage divider.Type: GrantFiled: March 18, 2009Date of Patent: May 15, 2012Assignee: Fujitsu LimitedInventors: Masaji Noguchi, Yutaka Kai, Setsuo Yoshida
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Patent number: 8139903Abstract: A driving circuit of a semiconductor optical amplifier type gate switch constituting a matrix optical switch is provided with an operation amplifier into which a driving signal is input and from which a current corresponding to the driving signal is output, an inductance element provided at an output terminal of the operation amplifier, and a circuit composed of a diode element and a resistor element connected in parallel and provided between the inductance element and the semiconductor optical amplifier.Type: GrantFiled: November 1, 2010Date of Patent: March 20, 2012Assignee: Fujitsu LimitedInventors: Masaji Noguchi, Tomohiro Ueno, Yutaka Kai, Setsuo Yoshida
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Patent number: 8107813Abstract: A drive circuit includes a first transistor that is controlled to be in on or off state in response to a control signal, and outputs, in on state, a positive current which is input from a first operational amplifier connected with a drain of the first transistor to a semiconductor optical amplifier; and a second transistor that is connected with a source of the first transistor, and is in inverse on or off state to the state of the first transistor. The drive circuit also includes a negative voltage circuit that is connected to a source of the second transistor, and outputs, when the second transistor is in on state, a negative current to the semiconductor optical amplifier.Type: GrantFiled: January 26, 2009Date of Patent: January 31, 2012Assignee: Fujitsu LimitedInventors: Setsuo Yoshida, Yutaka Kai, Masaji Noguchi
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Publication number: 20110050293Abstract: A driving circuit of a semiconductor optical amplifier type gate switch constituting a matrix optical switch is provided with an operation amplifier into which a driving signal is input and from which a current corresponding to the driving signal is output, an inductance element provided at an output terminal of the operation amplifier, and a circuit composed of a diode element and a resistor element connected in parallel and provided between the inductance element and the semiconductor optical amplifier.Type: ApplicationFiled: November 1, 2010Publication date: March 3, 2011Applicant: FUJITSU LIMITEDInventors: Masaji Noguchi, Tomohiro Ueno, Yutaka Kai, Setsuo Yoshida
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Patent number: 7898341Abstract: A non-inverting amplifier circuit is disclosed that includes an operational amplifier and a preemphasis circuit connected between the operational amplifier and a signal source. The preemphasis circuit is configured to compensate for the internal delay of a load connected to the output of the operational amplifier by emphasizing a high-frequency component of a signal fed from the signal source.Type: GrantFiled: August 26, 2008Date of Patent: March 1, 2011Assignee: Fujitsu LimitedInventors: Tomohiro Ueno, Masaji Noguchi, Yutaka Kai, Setsuo Yoshida
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Patent number: 7848600Abstract: A driving circuit of a semiconductor optical amplifier type gate switch constituting a matrix optical switch is provided with an operation amplifier into which a driving signal is input and from which a current corresponding to the driving signal is output, an inductance element provided at an output terminal of the operation amplifier, and a circuit composed of a diode element and a resistor element connected in parallel and provided between the inductance element and the semiconductor optical amplifier.Type: GrantFiled: March 27, 2007Date of Patent: December 7, 2010Assignee: Fujitsu LimitedInventors: Masaji Noguchi, Tomohiro Ueno, Yutaka Kai, Setsuo Yoshida
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Patent number: 7791793Abstract: A drive circuit is provided for a semiconductor optical amplifier type gate switch includes a first transmission path and a second transmission path. The first transmission path includes a common first sub-path between a signal source and a first node; and an individual second sub-path for each of a plurality of operational amplifiers between the first node and a corresponding one of the operational amplifiers. The second transmission path includes an individual third sub-path between each of the operational amplifiers and a second node; and a common fourth sub-path between the second node and the semiconductor optical amplifier type gate switches. Transmission delay times of all the individual second sub-paths are equal, and transmission delay times of all the individual third sub-paths are equal.Type: GrantFiled: December 19, 2007Date of Patent: September 7, 2010Assignee: Fujitsu LimitedInventors: Masaji Noguchi, Tomohiro Ueno, Yutaka Kai, Setsuo Yoshida
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Publication number: 20090297147Abstract: A drive circuit includes a first transistor that is controlled to be in on or off state in response to a control signal, and outputs, in on state, a positive current which is input from a first operational amplifier connected with a drain of the first transistor to a semiconductor optical amplifier; and a second transistor that is connected with a source of the first transistor, and is in inverse on or off state to the state of the first transistor. The drive circuit also includes a negative voltage circuit that is connected to a source of the second transistor, and outputs, when the second transistor is in on state, a negative current to the semiconductor optical amplifier.Type: ApplicationFiled: January 26, 2009Publication date: December 3, 2009Applicant: Fujitsu LimitedInventors: Setsuo YOSHIDA, Yutaka KAI, Masaji NOGUCHI
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Publication number: 20090237127Abstract: An optical-switch drive circuit including a driver unit that generates, in response to a control signal, an on/off signal for driving a semiconductor optical amplifier gate switch, and a buffer unit having a high input impedance and connected between an output terminal outputting the on/off signal and the semiconductor optical amplifier gate switch. In the optical-switch drive circuit the buffer unit may include a high-resistance voltage divider that is connected with the output terminal, and an operational amplifier that buffers, and provides to the semiconductor optical amplifier gate switch, a divided voltage of the voltage divider.Type: ApplicationFiled: March 18, 2009Publication date: September 24, 2009Applicant: FUJITSU LIMITEDInventors: Masaji NOGUCHI, Yutaka Kai, Setsuo Yoshida
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Patent number: 7561810Abstract: An optical communication apparatus for controlling the operating point of an optical modulation unit appropriately. An adding unit adds a bias voltage and a pilot signal. An optical modulation unit modulates light by an electrical signal, performs further modulation by a signal from the adding unit, and outputs an optical signal. A monitor unit monitors the level of the optical signal and outputs a monitor signal. A reference signal output unit outputs a reference in phase with the pilot signal contained in the monitor signal. A synchronous pilot-signal detection unit performs synchronous detection of the monitor signal by using the reference. A synchronous noise detection unit extracts noise from the monitor signal and performs synchronous detection of the noise by using the reference. A control signal output unit subtracts the synchronous detection value of the noise from that of the monitor signal, and outputs a control signal.Type: GrantFiled: October 5, 2006Date of Patent: July 14, 2009Assignee: Fujitsu LimitedInventors: Masaji Noguchi, Tomohiro Ueno
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Publication number: 20090058534Abstract: A non-inverting amplifier circuit is disclosed that includes an operational amplifier and a preemphasis circuit connected between the operational amplifier and a signal source. The preemphasis circuit is configured to compensate for the internal delay of a load connected to the output of the operational amplifier by emphasizing a high-frequency component of a signal fed from the signal source.Type: ApplicationFiled: August 26, 2008Publication date: March 5, 2009Applicant: FUJITSU LIMITEDInventors: Tomohiro UENO, Masaji Noguchi, Yutaka Kai, Setsuo Yoshida
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Publication number: 20080239472Abstract: A semiconductor optical amplification module that can suppress ringing without increasing power consumption or circuit size or inhibiting high-speed operation. A semiconductor optical amplifier outputs an optical signal inputted according to driving current outputted from a drive circuit. A diode is connected in parallel with the semiconductor optical amplifier. As a result, it becomes possible to suppress ringing without connecting a large resistor to the drive circuit.Type: ApplicationFiled: February 5, 2008Publication date: October 2, 2008Applicant: FUJITSU LIMITEDInventors: Masaji Noguchi, Tomohiro Ueno, Yutaka Kai, Setsuo Yoshida
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Publication number: 20080205888Abstract: A drive circuit is provided for a semiconductor optical amplifier type gate switch includes a first transmission path and a second transmission path. The first transmission path includes a common first sub-path between a signal source and a first node; and an individual second sub-path for each of a plurality of operational amplifiers between the first node and a corresponding one of the operational amplifiers. The second transmission path includes an individual third sub-path between each of the operational amplifiers and a second node; and a common fourth sub-path between the second node and the semiconductor optical amplifier type gate switches. Transmission delay times of all the individual second sub-paths are equal, and transmission delay times of all the individual third sub-paths are equal.Type: ApplicationFiled: December 19, 2007Publication date: August 28, 2008Applicant: Fujitsu LimitedInventors: Masaji Noguchi, Tomohiro Ueno, Yutaka Kai, Setsuo Yoshida
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Patent number: 7405858Abstract: An AOTF control apparatus, which applies an RF signal to an AOTF to allow a selected light to pass through the AOTF, includes: a first calculating unit calculating a relationship between a frequency of the RF signal and a wavelength of the selected light based on a frequency of the RF signal that allows a reference light to pass through the AOTF; and a second calculating unit calculating a relationship between a power of the RF signal and an attenuation amount of the selected light based on an input/output power of the reference signal at the input/output of the AOTF.Type: GrantFiled: May 31, 2006Date of Patent: July 29, 2008Assignee: Fujitsu LimitedInventors: Masaji Noguchi, Tomohiro Ueno, Goji Nakagawa, Yutaka Kai
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Patent number: 7349632Abstract: A method of wavelength selection control is disclosed.Type: GrantFiled: June 3, 2005Date of Patent: March 25, 2008Assignee: Fujitsu LimitedInventors: Masaji Noguchi, Toshihisa Kyouno, Tomohiro Ueno, Hideyuki Miyata, Yasuhiko Aoki
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Publication number: 20080068051Abstract: A driving circuit of a semiconductor optical amplifier type gate switch constituting a matrix optical switch is provided with an operation amplifier into which a driving signal is input and from which a current corresponding to the driving signal is output, an inductance element provided at an output terminal of the operation amplifier, and a circuit composed of a diode element and a resistor element connected in parallel and provided between the inductance element and the semiconductor optical amplifier.Type: ApplicationFiled: March 27, 2007Publication date: March 20, 2008Applicant: FUJITSU LIMITEDInventors: Masaji Noguchi, Tomohiro Ueno, Yutaka Kai, Setsuo Yoshida
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Publication number: 20070269223Abstract: An optical communication apparatus for controlling the operating point of an optical modulation unit appropriately. An adding unit adds a bias voltage and a pilot signal. An optical modulation unit modulates light by an electrical signal, performs further modulation by a signal from the adding unit, and outputs an optical signal. A monitor unit monitors the level of the optical signal and outputs a monitor signal. A reference signal output unit outputs a reference in phase with the pilot signal contained in the monitor signal. A synchronous pilot-signal detection unit performs synchronous detection of the monitor signal by using the reference. A synchronous noise detection unit extracts noise from the monitor signal and performs synchronous detection of the noise by using the reference. A control signal output unit subtracts the synchronous detection value of the noise from that of the monitor signal, and outputs a control signal.Type: ApplicationFiled: October 5, 2006Publication date: November 22, 2007Applicant: FUJITSU LIMITEDInventors: Masaji Noguchi, Tomohiro Ueno
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Publication number: 20070171505Abstract: An AOTF control apparatus, which applies an RF signal to an AOTF to allow a selected light to pass through the AOTF, includes: a first calculating unit calculating a relationship between a frequency of the RF signal and a wavelength of the selected light based on a frequency of the RF signal that allows a reference light to pass through the AOTF; and a second calculating unit calculating a relationship between a power of the RF signal and an attenuation amount of the selected light based on an input/output power of the reference signal at the input/output of the AOTF.Type: ApplicationFiled: May 31, 2006Publication date: July 26, 2007Applicant: FUJITSU LIMITEDInventors: Masaji Noguchi, Tomohiro Ueno, Goji Nakagawa, Yutaka Kai
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Publication number: 20070116404Abstract: A response-time storing unit stores a response time from start of output of driving force required for switching paths until stabilization of the driving force, for each of the paths to be connected. A driving-force correcting unit corrects output level of the driving force, starting correction of the output level of the driving force after the response time for a specified path stored in the response-time storing unit has passed since output of the driving force required for switching to the specified path started.Type: ApplicationFiled: February 28, 2006Publication date: May 24, 2007Applicant: FUJITSU LIMITEDInventors: Takashi Nakano, Masaji Noguchi, Tatsuji Satou, Tomohiro Ueno, Yutaka Kai, Yutaka Takita