Patents by Inventor Sosaku Sawada
Sosaku Sawada 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: 9182617Abstract: A driver with the arrangement of the travelling wave amplifier is disclosed. The driver provides n counts of cells each configuring the open collector arrangement and amplifying an input signal. The cells are arranged between an input interconnection and an output interconnection, and powered through the output interconnection. The power supply line to power the output interconnection is connected between m-th and (m+1)-th cells not through the output terminal of the output interconnection.Type: GrantFiled: March 5, 2013Date of Patent: November 10, 2015Assignee: Sumitomo Electric Industries, Ltd.Inventors: Taizo Tatsumi, Sosaku Sawada
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Patent number: 8987650Abstract: A front end module for an optical receiver is disclosed. The module includes a PD, a trans-impedance amplifier (TIA), an insulating carrier for mounting the PD, and a conductive base for mounting the carrier. The carrier provides first and second metal films thereon. The first metal film carries a photocurrent from the PD to the TIA, while, the second metal film carries the bias supply to the PD. The PD is mounted on the first and second metal films by the flip-chip arrangement. The second metal film surrounds the first metal film to suppress resonances appeared in the trans-impedance spectrum of the front end module.Type: GrantFiled: September 8, 2011Date of Patent: March 24, 2015Assignee: Sumitomo Electric Industries, Ltd.Inventors: Makoto Ito, Sosaku Sawada
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Patent number: 8907722Abstract: A traveling wave amplifier (TWA) with suppressed jitter is disclosed. The TWA includes a plurality of unit amplifiers with the differential arrangement comprised of a pair of transistors and a cascade transistors connected in series to the switching transistors. The unit amplifiers further includes current sources to provide idle currents to the cascade transistors. Even when the switching transistors fully turn off, the idle currents are provided to the cascade transistors, which set the operating point of the cascade transistor in a region where an increase of the base-emitter resistance is suppressed.Type: GrantFiled: May 16, 2013Date of Patent: December 9, 2014Assignee: Sumitomo Electric Industries, Ltd.Inventors: Taizo Tatsumi, Keiji Tanaka, Sosaku Sawada
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Differential amplifier with function of variable gain and optical receiver implemented with the same
Patent number: 8816772Abstract: A differential circuit with a function of a variable gain without shifting the output cross point is disclosed. The differential circuit includes an amplifying stage and a control stage. The amplifying stage includes three units each having a pair of transistors, a pair of load resistors, and a pair of current sources. The second and third units each put between the first unit and the load resistor to bypass the current. The control stage includes two units and two current sources to compensate the current bypassed by the second or third unit to keep the DC output level substantially in constant.Type: GrantFiled: July 12, 2011Date of Patent: August 26, 2014Assignee: Sumitomo Electric Industries, Ltd.Inventors: Yoshiyuki Sugimoto, Sosaku Sawada, Taizo Tatsumi -
Patent number: 8704592Abstract: A traveling wave amplifier (TWA) primarily for driving a semiconductor optical device is disclosed. The TWA of an embodiment provides a plurality of differential amplifiers of the first type and an additional differential amplifier of the second type, where are they are connected between the input and the output of the TWA. The differential amplifiers of the first type provide a first delay from the input to the output, while, the differential amplifier of the second type provide a second delay longer than the first delay between the input and the output of the TWA.Type: GrantFiled: March 23, 2012Date of Patent: April 22, 2014Assignee: Sumitomo Electric Industries, Ltd.Inventors: Taizou Tatsumi, Keiji Tanaka, Sosaku Sawada
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Publication number: 20130307619Abstract: A traveling wave amplifier (TWA) with suppressed jitter is disclosed. The TWA includes a plurality of unit amplifiers with the differential arrangement comprised of a pair of transistors and a cascade transistors connected in series to the switching transistors. The unit amplifiers further includes current sources to provide idle currents to the cascade transistors. Even when the switching transistors fully turn off, the idle currents are provided to the cascade transistors, which set the operating point of the cascade transistor in a region where an increase of the base-emitter resistance is suppressed.Type: ApplicationFiled: May 16, 2013Publication date: November 21, 2013Applicant: Sumitomo Electric Industries, Ltd.Inventors: Taizo TATSUMI, Keiji TANAKA, Sosaku SAWADA
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Publication number: 20130229699Abstract: A driver with the arrangement of the travelling wave amplifier is disclosed. The driver provides n counts of cells each configuring the open collector arrangement and amplifying an input signal. The cells are arranged between an input interconnection and an output interconnection, and powered through the output interconnection. The power supply line to power the output interconnection is connected between m-th and (m+1)-th cells not through the output terminal of the output interconnection.Type: ApplicationFiled: March 5, 2013Publication date: September 5, 2013Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.Inventors: Taizo TATSUMI, Sosaku SAWADA
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Patent number: 8390383Abstract: An amplifier for receiving an optical signal is disclosed. The amplifier provides a response time controller including an integrator with two time constants, a linear amplifier, a hysteresis comparator, an another integrator, and a switch to change the time constant. The switch includes two voltage followers, one of which turns off the switch to set the time constant in a longer state; while, the other of which turns on the switch and reflects the input of the integrator to set the time constant in a shorter state.Type: GrantFiled: September 8, 2011Date of Patent: March 5, 2013Assignee: Sumitomo Electric Industries, Ltd.Inventors: Hiroshi Hara, Sosaku Sawada
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Patent number: 8362841Abstract: A differential amplifier showing a suppressed output offset is disclosed. The differential amplifier includes a pair of differential transistors, a pair of cascode transistors, and a reference generator. One of differential transistors receives an AC signal, while, the other of differential transistors receives an average voltage of the AC signal. The reference generator receives the average voltage of the AC signal and outputs a bias commonly provided to the cascode transistor. The bias is raised by a substantially constant level from the average voltage, which compensates the output offset of the differential amplifier.Type: GrantFiled: March 31, 2011Date of Patent: January 29, 2013Assignee: Sumitomo Electric Industries, Ltd.Inventors: Makoto Ito, Sosaku Sawada
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Publication number: 20120249232Abstract: A traveling wave amplifier (TWA) primarily for driving a semiconductor optical device is disclosed. The TWA of an embodiment provides a plurality of differential amplifiers of the first type and an additional differential amplifier of the second type, where are they are connected between the input and the output of the TWA. The differential amplifiers of the first type provide a first delay from the input to the output, while, the differential amplifier of the second type provide a second delay longer than the first delay between the input and the output of the TWA.Type: ApplicationFiled: March 23, 2012Publication date: October 4, 2012Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.Inventors: Taizou TATSUMI, Keiji TANAKA, Sosaku SAWADA
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Publication number: 20120070121Abstract: A front end module for an optical receiver is disclosed. The module includes a PD, a trans-impedance amplifier (TIA), an insulating carrier for mounting the PD, and a conductive base for mounting the carrier. The carrier provides first and second metal films thereon. The first metal film carries a photocurrent from the PD to the TIA, while, the second metal film carries the bias supply to the PD. The PD is mounted on the first and second metal films by the flip-chip arrangement. The second metal film surrounds the first metal film to suppress resonances appeared in the trans-impedance spectrum of the front end module.Type: ApplicationFiled: September 8, 2011Publication date: March 22, 2012Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.Inventors: Makoto ITO, Sosaku Sawada
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Publication number: 20120032740Abstract: An amplifier for receiving an optical signal is disclosed. The amplifier provides a response time controller including an integrator with two time constants, a linear amplifier, a hysteresis comparator, an another integrator, and a switch to change the time constant. The switch includes two voltage followers, one of which turns off the switch to set the time constant in a longer state; while, the other of which turns on the switch and reflects the input of the integrator to set the time constant in a shorter state.Type: ApplicationFiled: September 8, 2011Publication date: February 9, 2012Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.Inventors: Hiroshi Hara, Sosaku Sawada
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DIFFERENTIAL AMPLIFIER WITH FUNCTION OF VARIABLE GAIN AND OPTICAL RECEIVER IMPLEMENTED WITH THE SAME
Publication number: 20120018622Abstract: A differential circuit with a function of a variable gain without shifting the output cross point is disclosed. The differential circuit includes an amplifying stage and a control stage. The amplifying stage includes three units each having a pair of transistors, a pair of load resistors, and a pair of current sources. The second and third units each put between the first unit and the load resistor to bypass the current. The control stage includes two units and two current sources to compensate the current bypassed by the second or third unit to keep the DC output level substantially in constant.Type: ApplicationFiled: July 12, 2011Publication date: January 26, 2012Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.Inventors: Yoshiyuki SUGIMOTO, Sosaku Sawada, Taizo Tatsumi -
Publication number: 20110241777Abstract: A differential amplifier showing a suppressed output offset is disclosed. The differential amplifier includes a pair of differential transistors, a pair of cascode transistors, and a reference generator. One of differential transistors receives an AC signal, while, the other of differential transistors receives an average voltage of the AC signal. The reference generator receives the average voltage of the AC signal and outputs a bias commonly provided to the cascode transistor. The bias is raised by a substantially constant level from the average voltage, which compensates the output offset of the differential amplifier.Type: ApplicationFiled: March 31, 2011Publication date: October 6, 2011Applicant: Sumitomo Electric Industries, Ltd.Inventors: Makoto Ito, Sosaku Sawada
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Patent number: 7755434Abstract: An electronic circuit includes a differential amplifier circuit, a first smoothing circuit, a second smoothing circuit and a first switch. The differential amplifier circuit receives a digital input signal and a reference signal. The first smoothing circuit smoothes the digital input signal with a first capacitance value. The second smoothing circuit smoothes the digital input signal with a second capacitance value larger than the first capacitance value. The first switch selects one of output signals from the first smoothing circuit and the second smoothing circuit as the reference signal.Type: GrantFiled: July 3, 2008Date of Patent: July 13, 2010Assignee: Eudyna Devices Inc.Inventors: Hiroshi Hara, Sosaku Sawada
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Patent number: 7585120Abstract: An optical device includes: a first optical component that has an end face oblique with respect to a plane perpendicular to an optical axis; a second optical component that is optically coupled to the first optical component; and a lens that is placed between the first optical component and the second optical component, and is positioned so that the trajectory of a focal point formed when the first optical component and the second optical component rotate relative to each other falls within a valid region on the surface of the second optical component.Type: GrantFiled: February 28, 2006Date of Patent: September 8, 2009Assignee: Eudyna Devices Inc.Inventors: Makoto Ito, Sosaku Sawada
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Patent number: 7579915Abstract: An electronic circuit includes: a control circuit that controls the gain of a transimpedance amplifier by taking part of an input current to be input to the transimpedance amplifier, based on the output voltage of the transimpedance amplifier; and a PIN diode that is provided between an input of the transimpedance amplifier and the control circuit, and is connected in the forward direction with respect to the current to be drawn into the control circuit.Type: GrantFiled: March 29, 2007Date of Patent: August 25, 2009Assignee: Eudyna Devices Inc.Inventors: Taizou Tatsumi, Sosaku Sawada
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Publication number: 20090009246Abstract: An electronic circuit includes a differential amplifier circuit, a first smoothing circuit, a second smoothing circuit and a first switch. The differential amplifier circuit receives a digital input signal and a reference signal. The first smoothing circuit smoothes the digital input signal with a first capacitance value. The second smoothing circuit smoothes the digital input signal with a second capacitance value larger than the first capacitance value. The first switch selects one of output signals from the first smoothing circuit and the second smoothing circuit as the reference signal.Type: ApplicationFiled: July 3, 2008Publication date: January 8, 2009Applicant: EUDYNA DEVICES INC.Inventors: Hiroshi HARA, Sosaku SAWADA
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Publication number: 20070229172Abstract: An electronic circuit includes: a control circuit that controls the gain of a transimpedance amplifier by taking part of an input current to be input to the transimpedance amplifier, based on the output voltage of the transimpedance amplifier; and a PIN diode that is provided between an input of the transimpedance amplifier and the control circuit, and is connected in the forward direction with respect to the current to be drawn into the control circuit.Type: ApplicationFiled: March 29, 2007Publication date: October 4, 2007Applicant: EUDYNA DEVICES INC.Inventors: Taizou Tatsumi, Sosaku Sawada
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Publication number: 20060193568Abstract: An optical device includes: a first optical component that has an end face oblique with respect to a plane perpendicular to an optical axis; a second optical component that is optically coupled to the first optical component; and a lens that is placed between the first optical component and the second optical component, and is positioned so that the trajectory of a focal point formed when the first optical component and the second optical component rotate relative to each other falls within a valid region on the surface of the second optical component.Type: ApplicationFiled: February 28, 2006Publication date: August 31, 2006Applicant: EUDYNA DEVICES INC.Inventors: Makoto Ito, Sosaku Sawada