Patents by Inventor Shinji Iwatsuka
Shinji Iwatsuka 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: 10649246Abstract: A dielectric thin film-applied substrate that suppresses occurrence of cracks when the film thickness of the lithium niobate film is equal to or larger than 1 ?m. The dielectric thin film-applied substrate includes a single crystal substrate and a dielectric thin film made of c-axis oriented lithium niobate epitaxially formed on a main surface of the single crystal substrate. The dielectric thin film has a twin crystal structure including first and second crystals 180° apart, centered on the c-axis. In pole figure measurement by X-ray diffraction, the ratio between a first diffraction intensity corresponding to the first crystal and a second diffraction intensity corresponding to the second crystal is equal to or higher than 0.5 and equal to or lower than 2.0, which alleviates distortions accumulated inside the lithium niobate film and supresses occurrences of cracks accompanying increases in the film thickness.Type: GrantFiled: July 14, 2017Date of Patent: May 12, 2020Assignee: TDK CORPORATIONInventors: Kenji Sasaki, Shinji Iwatsuka
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Patent number: 10591801Abstract: A single drive type optical modulator has good high-frequency characteristics and reduced wavelength chirp of the modulated light. An optical modulator is provided with a Mach-Zehnder optical waveguide including first and second optical waveguides, a buffer layer covering the first and second optical waveguides, and an electrode layer including first and second ground electrodes and a signal electrode positioned between the first and second ground electrodes in a plan view. The signal electrode has a first lower surface covering the first optical waveguide through the buffer layer, the first ground electrode has a first lower surface covering the second optical waveguide through the buffer layer and a second lower surface positioned above the first lower surface, and a gap between the signal electrode and the second ground electrode that is larger than a gap between the signal electrode and the first ground electrode.Type: GrantFiled: April 7, 2017Date of Patent: March 17, 2020Assignee: TDK CORPORATIONInventors: Shinji Iwatsuka, Kenji Sasaki
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Patent number: 10585328Abstract: Disclosed herein is an optical waveguide element that includes a substrate and a waveguide layer formed on the substrate and comprising lithium niobate. The waveguide layer has a slab part having a predetermined thickness and a ridge part protruding from the slab part. The maximum thickness of the slab part is 0.05 times or more and less than 0.4 times a wavelength of a light propagating in the ridge part.Type: GrantFiled: May 13, 2019Date of Patent: March 10, 2020Assignee: TDK CORPORATIONInventors: Shinji Iwatsuka, Kenji Sasaki, Satoshi Shirai
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Publication number: 20190293972Abstract: A dielectric thin film-applied substrate capable of suppressing occurrence of cracks even when the film thickness of the lithium niobate film is made, e.g., equal to or larger than 1 ?m. The dielectric thin film-applied substrate includes a single crystal substrate and a dielectric thin film which is made of c-axis oriented lithium niobate and epitaxially formed on a main surface of the single crystal substrate. The dielectric thin film has a twin crystal structure including a first and crystals existing at a position obtained by rotating the first crystal 180° centered on the c-axis. In pole figure measurement by an X-ray diffraction method, the ratio between a first diffraction intensity corresponding to the first crystal and a second diffraction intensity corresponding to the second crystal is equal to or higher than 0.5 and equal to or lower than 2.0.Type: ApplicationFiled: July 14, 2017Publication date: September 26, 2019Applicant: TDK CORPORATIONInventors: Kenji SASAKI, Shinji IWATSUKA
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Publication number: 20190271897Abstract: Disclosed herein is an optical waveguide element that includes a substrate and a waveguide layer formed on the substrate and comprising lithium niobate. The waveguide layer has a slab part having a predetermined thickness and a ridge part protruding from the slab part. The maximum thickness of the slab part is 0.05 times or more and less than 0.4 times a wavelength of a light propagating in the ridge part.Type: ApplicationFiled: May 13, 2019Publication date: September 5, 2019Applicant: TDK CorporationInventors: Shinji IWATSUKA, Kenji SASAKI, Satoshi SHIRAI
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Patent number: 10359684Abstract: Disclosed herein is an optical waveguide element that includes a substrate and a waveguide layer formed on the substrate and comprising lithium niobate. The waveguide layer has a slab part having a predetermined thickness and a ridge part protruding from the slab part. The maximum thickness of the slab part is 0.05 times or more and less than 0.4 times a wavelength of a light propagating in the ridge part.Type: GrantFiled: November 9, 2018Date of Patent: July 23, 2019Assignee: TDK CORPORATIONInventors: Shinji Iwatsuka, Kenji Sasaki, Satoshi Shirai
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Publication number: 20190146302Abstract: A single drive type optical modulator has good high-frequency characteristics and reduced wavelength chirp of the modulated light. An optical modulator is provided with a Mach-Zehnder optical waveguide including first and second optical waveguides, a buffer layer covering the first and second optical waveguides, and an electrode layer including first and second ground electrodes and a signal electrode positioned between the first and second ground electrodes in a plan view. The signal electrode has a first lower surface covering the first optical waveguide through the buffer layer, the first ground electrode has a first lower surface covering the second optical waveguide through the buffer layer and a second lower surface positioned above the first lower surface, and a gap between the signal electrode and the second ground electrode that is larger than a gap between the signal electrode and the first ground electrode.Type: ApplicationFiled: April 7, 2017Publication date: May 16, 2019Applicant: TDK CORPORATIONInventors: Shinji IWATSUKA, Kenji SASAKI
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Publication number: 20190079366Abstract: Disclosed herein is an optical waveguide element that includes a substrate and a waveguide layer formed on the substrate and comprising lithium niobate. The waveguide layer has a slab part having a predetermined thickness and a ridge part protruding from the slab part. The maximum thickness of the slab part is 0.05 times or more and less than 0.4 times a wavelength of a light propagating in the ridge part.Type: ApplicationFiled: November 9, 2018Publication date: March 14, 2019Applicant: TDK CorporationInventors: Shinji IWATSUKA, Kenji Sasaki, Satoshi Shirai
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Patent number: 10203583Abstract: Disclosed herein is an optical waveguide element that includes a substrate and a waveguide layer formed on the substrate and comprising lithium niobate. The waveguide layer has a slab part having a predetermined thickness and a ridge part protruding from the slab part. The maximum thickness of the slab part is 0.05 times or more and less than 0.4 times a wavelength of a light propagating in the ridge part.Type: GrantFiled: February 27, 2018Date of Patent: February 12, 2019Assignee: TDK CORPORATIONInventors: Shinji Iwatsuka, Kenji Sasaki, Satoshi Shirai
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Publication number: 20180188629Abstract: Disclosed herein is an optical waveguide element that includes a substrate and a waveguide layer formed on the substrate and comprising lithium niobate. The waveguide layer has a slab part having a predetermined thickness and a ridge part protruding from the slab part. The maximum thickness of the slab part is 0.05 times or more and less than 0.4 times a wavelength of a light propagating in the ridge part.Type: ApplicationFiled: February 27, 2018Publication date: July 5, 2018Applicant: TDK CorporationInventors: Shinji Iwatsuka, Kenji Sasaki, Satoshi Shirai
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Patent number: 9939709Abstract: Disclosed herein is an optical waveguide element that includes a substrate and a waveguide layer formed on the substrate and comprising lithium niobate. The waveguide layer has a slab part having a predetermined thickness and a ridge part protruding from the slab part. The maximum thickness of the slab part is 0.05 times or more and less than 0.4 times a wavelength of a light propagating in the ridge part.Type: GrantFiled: August 15, 2016Date of Patent: April 10, 2018Assignee: TDK CORPORATIONInventors: Shinji Iwatsuka, Kenji Sasaki, Satoshi Shirai
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Publication number: 20170052424Abstract: Disclosed herein is an optical waveguide element that includes a substrate and a waveguide layer formed on the substrate and comprising lithium niobate. The waveguide layer has a slab part having a predetermined thickness and a ridge part protruding from the slab part. The maximum thickness of the slab part is 0.05 times or more and less than 0.4 times a wavelength of a light propagating in the ridge part.Type: ApplicationFiled: August 15, 2016Publication date: February 23, 2017Applicant: TDK CorporationInventors: Shinji IWATSUKA, Kenji Sasaki, Satoshi Shirai
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Patent number: 9244296Abstract: An optical modulator includes a single-crystal substrate, a lithium niobate film formed on a main surface of the single-crystal substrate, the lithium niobate film being an epitaxial film and having a ridge, a buffer layer formed on the ridge, a first electrode formed on the buffer layer, and a second electrode separated from the first electrode, the second electrode being in contact with the lithium niobate film.Type: GrantFiled: October 30, 2014Date of Patent: January 26, 2016Assignee: TDK CORPORATIONInventors: Shinji Iwatsuka, Kenji Sasaki, Masamichi Taniguchi
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Publication number: 20150138619Abstract: An optical modulator includes a single-crystal substrate, a lithium niobate film formed on a main surface of the single-crystal substrate, the lithium niobate film being an epitaxial film and having a ridge, a buffer layer formed on the ridge, a first electrode formed on the buffer layer, and a second electrode separated from the first electrode, the second electrode being in contact with the lithium niobate film.Type: ApplicationFiled: October 30, 2014Publication date: May 21, 2015Inventors: Shinji IWATSUKA, Kenji SASAKI, Masamichi TANIGUCHI
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Patent number: 7444040Abstract: The invention relates to a magneto-optical component, such as a variable light attenuator, light modulator or optical switch, having small size, low power consumption and high speed. The magneto-optical component comprises at least one Faraday rotator comprising a magnetic domain A with magnetization in a direction perpendicular to a light incident/exit surface, a magnetic domain B with magnetization in a direction opposite to the magnetization direction of the magnetic domain A, a planar magnetic domain wall as a boundary between the magnetic domain A and the magnetic domain B, and two light transmission regions through which a plurality of light beams comprising identical traveling directions are transmitted respectively and whose distances from the magnetic domain wall are almost equal to each other, and a magnetic field application system for applying a variable magnetic field to the Faraday rotator to make a position of the magnetic domain wall variable.Type: GrantFiled: January 21, 2005Date of Patent: October 28, 2008Assignee: TDK CorporationInventor: Shinji Iwatsuka
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Patent number: 7072111Abstract: A reflection-type optical device used for an optical communication system, in which an element structure can be simplified and excellent optical characteristics are obtained. The reflection-type optical device includes a birefringent plate, a magnetic domain A of a Faraday rotator, a magnetic domain B of the Faraday rotator, a birefringent plate which allows the light beams to pass through as extraordinary rays, and a birefringent plate which allows a light beam having been reflected by a reflecting film and having passed through the birefringent plate and the magnetic domain A to pass through as an extraordinary ray, allows a light having been reflected by the reflecting film and having passed through the birefringent plate and the magnetic domain B to pass through as an ordinary ray, and emits a light beam from a light incoming/outgoing port.Type: GrantFiled: October 15, 2004Date of Patent: July 4, 2006Assignee: TDK CorporationInventor: Shinji Iwatsuka
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Patent number: 7002732Abstract: The invention provides small-sized, power-saving and easily-producible magneto-optical devices. The magneto-optical device comprises a Faraday rotator having nearly parallel surfaces and a Z-direction magnetic easy axis; a total reflection film formed partly on one surface of the Faraday rotator; another total reflection film formed partly on the other surface thereof; a light input region through which light enters the Faraday rotator; a light output region through which the light having alternately reflected on the total reflection films goes out of the Faraday rotator; a permanent magnet that forms a predetermined magnetic domain structure in the Faraday rotator and applies a magnetic field component in the Z-direction to the Faraday rotator so that the magnetization direction could be the same both in the light input region and the light output region; and an electromagnet that varies the position at which the magnetic field component applied to the Faraday rotator is 0 (zero).Type: GrantFiled: August 24, 2004Date of Patent: February 21, 2006Assignee: TDK CorporationInventor: Shinji Iwatsuka
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Publication number: 20050179980Abstract: The invention relates to a magneto-optical component used for an optical communication system, such as a variable light attenuator, alight modulator or an optical switch, and comprises an object to provide the magneto-optical component which comprises small size, low power consumption and high speed.Type: ApplicationFiled: January 21, 2005Publication date: August 18, 2005Applicant: TDK CORPORATIONInventor: Shinji Iwatsuka
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Publication number: 20050146769Abstract: The invention provides small-sized, power-saving and easily-producible magneto-optical devices. The magneto-optical device comprises a Faraday rotator having nearly parallel surfaces and a Z-direction magnetic easy axis; a total reflection film formed partly on one surface of the Faraday rotator; another total reflection film formed partly on the other surface thereof; a light input region through which light enters the Faraday rotator; a light output region through which the light having alternately reflected on the total reflection films goes out of the Faraday rotator; a permanent magnet that forms a predetermined magnetic domain structure in the Faraday rotator and applies a magnetic field component in the Z-direction to the Faraday rotator so that the magnetization direction could be the same both in the light input region and the light output region; and an electromagnet that varies the position at which the magnetic field component applied to the Faraday rotator is 0 (zero).Type: ApplicationFiled: August 24, 2004Publication date: July 7, 2005Applicant: TDK CORPORATIONInventor: Shinji Iwatsuka
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Publication number: 20050111102Abstract: A reflection-type optical device used for an optical communication system, in which an element structure can be simplified and excellent optical characteristics are obtained. The reflection-type optical device includes a birefringent plate, a magnetic domain A of a Faraday rotator, a magnetic domain B of the Faraday rotator, a birefringent plate which allows the light beams to pass through as extraordinary rays, and a birefringent plate which allows a light beam having been reflected by a reflecting film and having passed through the birefringent plate and the magnetic domain A to pass through as an extraordinary ray, allows a light having been reflected by the reflecting film and having passed through the birefringent plate and the magnetic domain B to pass through as an ordinary ray, and emits a light beam from a light incoming/outgoing port.Type: ApplicationFiled: October 15, 2004Publication date: May 26, 2005Applicant: TDK CorporationInventor: Shinji Iwatsuka