Patents by Inventor Yumi Nakazawa
Yumi Nakazawa 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: 7476038Abstract: An optical device module includes an optical device, a soaking unit fixed to one surface of the optical device, a heating/cooling unit fixed to one surface of the soaking unit, a heat-insulating unit fixed to one surface of the heating/cooling unit, and a package that houses the optical device, the soaking unit, the heating/cooling unit, and the heat-insulating unit and to which the heat-insulating unit is fixed. The heating/cooling unit heats the optical device using self-generated heat or cools the optical device via the soaking unit.Type: GrantFiled: March 22, 2004Date of Patent: January 13, 2009Assignee: Fujitsu LimitedInventors: Yoichi Oikawa, Hirofumi Aota, Kazuaki Akimoto, Hideyuki Miyata, Yumi Nakazawa, legal representative, Tadao Nakazawa
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Patent number: 7430344Abstract: An acousto-optic device is disclosed which can achieve both of suppression of secular change and prevention of device damage and can maintain a stabilized wavelength selection filtering operation. The acousto-optic device includes a substrate on which a SAW guide for guiding a surface acoustic wave and an optical waveguide for guiding an optical wave are provided. A pyro-electricity coping conductive wiring pattern is provided in a region of the substrate other than the SAW guide and neutralizes polarization charge generated on a surface of the substrate.Type: GrantFiled: March 22, 2007Date of Patent: September 30, 2008Assignee: Fujitsu LimitedInventors: Hiroshi Miyata, Yukito Tsunoda, Tadao Nakazawa, Yumi Nakazawa
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Patent number: 7302121Abstract: The present invention is directed toward an optical device and a drive voltage supply device, which prevent occurrence of a DC drift and enable stable selection of light of desired wavelength without deteriorating a filtering characteristic. The optical device comprises a substrate having an electrooptical effect; an optical waveguide formed in this substrate; a plurality of comb electrode pairs which are arranged side by side along the optical waveguide, can apply an electric field for said electrooptical effect, and are formed from respective pairs of comb electrodes; and drive voltage supply means capable of supplying a drive voltage to said comb electrode pairs such that the voltage changes with time.Type: GrantFiled: March 22, 2005Date of Patent: November 27, 2007Assignee: Fujitsu LimitedInventors: Yumi Nakazawa, legal representative, Hiroshi Miyata, Yukito Tsunoda, Tadao Nakazawa, deceased
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Publication number: 20070189655Abstract: An acousto-optic device is disclosed which can achieve both of suppression of secular change and prevention of device damage and can maintain a stabilized wavelength selection filtering operation. The acousto-optic device includes a substrate on which a SAW guide for guiding a surface acoustic wave and an optical waveguide for guiding an optical wave are provided. A pyro-electricity coping conductive wiring pattern is provided in a region of the substrate other than the SAW guide and neutralizes polarization charge generated on a surface of the substrate.Type: ApplicationFiled: March 22, 2007Publication date: August 16, 2007Applicant: Fujitsu LimitedInventors: Hiroshi Miyata, Yukito Tsunoda, Tadao Nakazawa, Yumi Nakazawa
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Patent number: 7155072Abstract: In relation to an optical modulator (e.g., an RZ optical modulator) formed from a plurality of Mach-Zehnder optical modulators, in an attempt to make the optical modulator compact and realize a low drive voltage, the optical modulator is formed by comprising a plurality of Mach-Zehnder optical modulators, each including a substrate exhibiting an electro-optical effect, an optical waveguide formed on the substrate, and electrodes formed in the vicinity of the optical waveguide. The plurality of Mach-Zehnder optical modulators are arranged on the substrate and connected into multistage.Type: GrantFiled: March 23, 2005Date of Patent: December 26, 2006Assignee: Fujitsu LimitedInventors: Masaki Sugiyama, Masaharu Doi, Yumi Nakazawa, legal representative, Tadao Nakazawa, deceased
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Patent number: 7151866Abstract: An optical device module includes an optical device with a plurality of electrodes disposed at predetermined positions, a substrate disposed oppositely to the optical device and with wiring patterns for connecting to the electrodes, and a wiring which connects the electrodes to the wiring patterns.Type: GrantFiled: March 24, 2004Date of Patent: December 19, 2006Assignee: Fujitsu LimitedInventors: Yoichi Oikawa, Hirofumi Aota, Kazuaki Akimoto, Hideyuki Miyata, Yumi Nakazawa, legal representative, Tadao Nakazawa, deceased
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Patent number: 7095559Abstract: In a variable optical delay circuit to be used for compensation for polarization mode dispersion of an optical signal and for other purposes, there are provided a first birefringent member, a second birefringent member and a variable optical rotator interposed between the first birefringent member and the second birefringent member for varying a polarization state of light outputted from the first birefringent member. The birefringent members and the variable optical rotator are disposed on the same optical axis, and the optical axis of each of the birefringent members is set to perpendicularly intersect a traveling direction of inputted light. Therefore, by varying the optical rotation angle of the variable optical rotator, an arbitrary delay quantity corresponding thereto is obtainable in a continuous (analog-like) fashion without undergoing spatial separation between polarization components of the inputted light and varying the intensity (loss) of each of the polarization components.Type: GrantFiled: March 23, 2005Date of Patent: August 22, 2006Assignee: Fujitsu LimitedInventors: Shinji Taniguchi, Tadao Nakazawa, deceased, Yumi Nakazawa, legal representative, Masaharu Doi
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Patent number: 7088875Abstract: An object of the invention is to provide a Mach-Zehnder type optical modulator that can reduce wavelength chirp occurring in a modulated light, and also can reduce an optical loss with a small sized configuration. To this end, according to the present Mach-Zehnder type optical modulator, in a configuration where optical waveguides and a coplanar electrode are formed on a substrate having an electro-optical effect, a polarization inversed region is formed in a part of an interaction portion of the substrate, and a signal electrode is arranged above one of parallel waveguides in a polarization inversed region and is arranged above the other parallel waveguide in a non-inversed region. Furthermore, a surface area of the substrate positioned on both sides of each of the parallel waveguides is lowered to provide a ridge structure section, and a buffer layer is formed on a ridge side face thereof.Type: GrantFiled: June 22, 2004Date of Patent: August 8, 2006Assignee: Fujitsu LimitedInventors: Masaki Sugiyama, Yumi Nakazawa, legal representative, Tadao Nakazawa, deceased
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Publication number: 20060126988Abstract: The present invention is directed toward an optical device and a drive voltage supply device, which prevent occurrence of a d.c. drift and enable stable selection of light of desired wavelength without deteriorating a filtering characteristic. The optical device comprises a substrate having an electrooptical effect; an optical waveguide formed in this substrate; a plurality of comb electrode pairs which are arranged side by side along the optical waveguide, can apply an electric field for said electrooptical effect, and are formed from respective pairs of comb electrodes; and drive voltage supply means capable of supplying a drive voltage to said comb electrode pairs such that the voltage changes with time.Type: ApplicationFiled: March 22, 2005Publication date: June 15, 2006Applicant: Fujitsu LimitedInventors: Tadao Nakazawa, Yumi Nakazawa, Hiroshi Miyata, Yukito Tsunoda
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Publication number: 20060002436Abstract: A wavelength tunable laser is constituted by including a resonator composed of a pair of reflectors arranged to face each other, and inside the resonator, a SOA radiating a laser beam with a gain for a wide range of wavelengths, a transmission-type wavelength tunable filter having an asymmetric filter characteristic, and a phase controller controlling a phase of the laser beam resonating inside the resonator.Type: ApplicationFiled: December 29, 2004Publication date: January 5, 2006Applicant: FUJITSU LIMITEDInventors: Kazumasa Takabayashi, Tadao Nakazawa, Yumi Nakazawa, Takashi Shiraishi
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Publication number: 20050259906Abstract: An acousto-optic device is disclosed which can achieve both of suppression of secular change and prevention of device damage and can maintain a stabilized wavelength selection filtering operation. The acousto-optic device includes a substrate on which a SAW guide for guiding a surface acoustic wave and an optical waveguide for guiding an optical wave are provided. A pyro-electricity coping conductive wiring pattern is provided in a region of the substrate other than the SAW guide and neutralizes polarization charge generated on a surface of the substrate.Type: ApplicationFiled: September 22, 2004Publication date: November 24, 2005Applicant: Fujitsu LimitedInventors: Hiroshi Miyata, Yukito Tsunoda, Tadao Nakazawa, Yumi Nakazawa
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Publication number: 20050231786Abstract: In a variable optical delay circuit to be used for compensation for polarization mode dispersion of an optical signal and for other purposes, there are provided a first birefringent member, a second birefringent member and a variable optical rotator interposed between the first birefringent member and the second birefringent member for varying a polarization state of light outputted from the first birefringent member. The birefringent members and the variable optical rotator are disposed on the same optical axis, and the optical axis of each of the birefringent members is set to perpendicularly intersect a traveling direction of inputted light. Therefore, by varying the optical rotation angle of the variable optical rotator, an arbitrary delay quantity corresponding thereto is obtainable in a continuous (analog-like) fashion without undergoing spatial separation between polarization components of the inputted light and varying the intensity (loss) of each of the polarization components.Type: ApplicationFiled: March 23, 2005Publication date: October 20, 2005Inventors: Shinji Taniguchi, Tadao Nakazawa, Yumi Nakazawa, Masaharu Doi
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Publication number: 20050213863Abstract: In relation to an optical modulator (e.g., an RZ optical modulator) formed from a plurality of Mach-Zehnder optical modulators, in an attempt to make the optical modulator compact and realize a low drive voltage, the optical modulator is formed by comprising a plurality of Mach-Zehnder optical modulators, each including a substrate exhibiting an electro-optical effect, an optical waveguide formed on the substrate, and electrodes formed in the vicinity of the optical waveguide. The plurality of Mach-Zehnder optical modulators are arranged on the substrate and connected into multistage.Type: ApplicationFiled: March 23, 2005Publication date: September 29, 2005Applicant: Fujitsu LimitedInventors: Masaki Sugiyama, Masaharu Doi, Tadao Nakazawa, Yumi Nakazawa
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Publication number: 20050175271Abstract: An object of the invention is to provide a Mach-Zehnder type optical modulator that can reduce wavelength chirp occurring in a modulated light, and also can reduce an optical loss with a small sized configuration. To this end, according to the present Mach-Zehnder type optical modulator, in a configuration where optical waveguides and a coplanar electrode are formed on a substrate having an electro-optical effect, a polarization inversed region is formed in a part of an interaction portion of the substrate, and a signal electrode is arranged above one of parallel waveguides in a polarization inversed region and is arranged above the other parallel waveguide in a non-inversed region. Furthermore, a surface area of the substrate positioned on both sides of each of the parallel waveguides is lowered to provide a ridge structure section, and a buffer layer is formed on a ridge side face thereof.Type: ApplicationFiled: June 22, 2004Publication date: August 11, 2005Applicant: Fujitsu LimitedInventors: Masaki Sugiyama, Tadao Nakazawa, Yumi Nakazawa
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Publication number: 20050089282Abstract: An optical device module includes an optical device, a soaking unit fixed to one surface of the optical device, a heating/cooling unit fixed to one surface of the soaking unit, a heat-insulating unit fixed to one surface of the heating/cooling unit, and a package that houses the optical device, the soaking unit, the heating/cooling unit, and the heat-insulating unit and to which the heat-insulating unit is fixed. The heating/cooling unit heats the optical device using self-generated heat or cools the optical device via the soaking unit.Type: ApplicationFiled: March 22, 2004Publication date: April 28, 2005Applicant: FUJITSU LIMITEDInventors: Yoichi Oikawa, Hirofumi Aota, Kazuaki Akimoto, Hideyuki Miyata, Tadao Nakazawa, Yumi Nakazawa
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Publication number: 20050089275Abstract: An optical device module includes an optical device with a plurality of electrodes disposed at predetermined positions, a substrate disposed oppositely to the optical device and with wiring patterns for connecting to the electrodes, and a wiring which connects the electrodes to the wiring patterns.Type: ApplicationFiled: March 24, 2004Publication date: April 28, 2005Applicant: FUJITSU LIMITEDInventors: Yoichi Oikawa, Hirofumi Aota, Kazuaki Akimoto, Hideyuki Miyata, Yumi Nakazawa, Tadao Nakazawa