Patents by Inventor Makoto Shimokozono
Makoto Shimokozono 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: 20220360046Abstract: A first current injection unit that injects a DBR current into a rear DBR region and a front DBR region and a second current injection unit that injects a phase adjustment current into a phase adjustment region are included. The second current injection unit injects the phase adjustment current that changes at a frequency that is twice as much as that of the DBR current into the phase adjustment region in synchronization with the DBR current. The first current injection unit inverts the DBR current to a positive value in a region in which the DBR current is a negative value.Type: ApplicationFiled: July 3, 2019Publication date: November 10, 2022Inventor: Makoto Shimokozono
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Patent number: 7492975Abstract: The present invention provides an optical switch, an optical modulator, and a wavelength variable filter each of which has a simple configuration, which requires only a low driving voltage, which is independent of polarization, and which can operate at high speed. An optical switch according to the present invention includes a 3-dB coupler (16) placed on an input, a 3-dB coupler (17) placed on an output, and two optical waveguides connecting the input-side 3-dB coupler and the output-side 3-dB coupler together. The optical switch also includes a phase modulating section (18) that applies electric fields to one or both of the two optical waveguides. At least two optical waveguides are a crystal material including KTaxNb1-xO3 (0<x<1) and KxLi1-xTayNb1-yO3 (0<x<1, 0<y<1), or KTaxNb1-xO3 or KxLi1-xTayNb1-yO3.Type: GrantFiled: March 18, 2004Date of Patent: February 17, 2009Assignee: Nippon Telegraph and Telephone CorporationInventors: Seiji Toyoda, Kazuo Fujiura, Masahiro Sasaura, Koji Enbutsu, Makoto Shimokozono, Tadayuki Imai, Akiyuki Tate, Touru Matsuura, Takashi Kurihara, Hiroshi Fushimi
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Patent number: 7356227Abstract: An optical switch, an optical modulator, and a wavelength variable filter each have a simple configuration, which requires only a low driving voltage, which is independent of polarization, and which can operate at high speed. An optical switch includes a 3-dB coupler placed on an output, a 3-dB coupler placed on an output, and two optical waveguides connecting the input-side 3-dB coupler and the output-side 3-dB coupler together. The optical switch also includes a phase modulating section that applies electric fields to one or both of the two optical waveguides. At least two optical waveguides are a crystal material including KTaxNb1-xO3 (0<x<1) and KxLi1-xTayNb1-yO3 (0<x<1, 0<y<1), or KTaxNb1-xO3 or KxLi1-xTayNb1-yO3.Type: GrantFiled: October 4, 2006Date of Patent: April 8, 2008Assignee: Nippon Telegraph and Telephone CorporationInventors: Seiji Toyoda, Kazuo Fujiura, Masahiro Sasaura, Koji Enbutsu, Makoto Shimokozono, Tadayuki Imai, Akiyuki Tate, Touru Matsuura, Takashi Kurihara, Hiroshi Fushimi
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Patent number: 7340116Abstract: An optical switch, an optical modulator, and a wavelength variable filter each have a simple configuration, which requires only a low driving voltage, which is independent of polarization, and which can operate at high speed. An optical switch includes a 3-dB coupler placed on an output, a 3-dB coupler placed on an output, and two optical waveguides connecting the input-side 3-dB coupler and the output-side 3-dB coupler together. The optical switch also includes a phase modulating section that applies electric fields to one or both of the two optical waveguides. At least two optical waveguides are a crystal material including KTaxNb1-xO3 (0<x<1) and KxLi1-xTayNb1-yO3 (0<x<1, 0<y<1), or KTaxNb1-xO3 or KxLi1-xTayNb1-yO3.Type: GrantFiled: October 4, 2006Date of Patent: March 4, 2008Assignee: Nippon Telegraph and Telephone CorporationInventors: Seiji Toyoda, Kazuo Fujiura, Masahiro Sasaura, Koji Enbutsu, Makoto Shimokozono, Tadayuki Imai, Akiyuki Tate, Touru Matsuura, Takashi Kurihara, Hiroshi Fushimi
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Patent number: 7340147Abstract: The invention provides an optical waveguide material whose refractive index can be tailored without changing the ratio of Ta and Nb. An optical waveguide of this invention comprising an under-clad layer 1 and a core 2 that is formed on the under-clad layer 1 and has a higher refractive index than that of the under-clad layer 1 is shown. For example, KTN (KTa1-xNbxO3) is used as the core 2, and a material that is obtained by substituting at least one element selected from the group consisting of Zr, Hf, and Sn for a portion of one element of the constituent elements of KTN and has the same perovskite type crystal structure as KTN is used as the clad. The refractive index of KTN can be reduced considerably, and this controllability widens the degree of freedom in the design of optical waveguide devices.Type: GrantFiled: May 24, 2006Date of Patent: March 4, 2008Assignee: Nippon Telegraph and Telephone CorporationInventors: Tadayuki Imai, Kazuo Fujiura, Makoto Shimokozono, Seiji Toyoda, Masahiro Sasaura, Tohru Matsuura
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Patent number: 7336854Abstract: An optical switch, an optical modulator, and a wavelength variable filter each have a simple configuration, which requires only a low driving voltage, which is independent of polarization, and which can operate at high speed. An optical switch includes a 3-dB coupler placed on an output, a 3-dB coupler placed on an output, and two optical waveguides connecting the input-side 3-dB coupler and the output-side 3-dB coupler together. The optical switch also includes a phase modulating section that applies electric fields to one or both of the two optical waveguides. At least two optical waveguides are a crystal material including KTaxNb1-xO3 (0<x<1) and KxLi1-xTayNb1-yO3 (0<x<1, 0<y<1), or KTaxNb1-xO3 or KxLi1-xTayNb1-yO3.Type: GrantFiled: October 4, 2006Date of Patent: February 26, 2008Assignee: Nippon Telegraph and Telephone CorporationInventors: Seiji Toyoda, Kazuo Fujiura, Masahiro Sasaura, Koji Enbutsu, Makoto Shimokozono, Tadayuki Imai, Akiyuki Tate, Touru Matsuura, Takashi Kurihara, Hiroshi Fushimi
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Publication number: 20070253659Abstract: An optical switch, an optical modulator, and a wavelength variable filter each have a simple configuration, which requires only a low driving voltage, which is independent of polarization, and which can operate at high speed. An optical switch includes a 3-dB coupler placed on an output, a 3-dB coupler placed on an output, and two optical waveguides connecting the input-side 3-dB coupler and the output-side 3-dB coupler together. The optical switch also includes a phase modulating section that applies electric fields to one or both of the two optical waveguides. At least two optical waveguides are a crystal material including KTaxNb1-xO3 (0<x<1) and KxLi1-xTayNb1-yO3 (0<x<1, 0<y<1), or KTaxNb1-xO3 or KxLi1-xTayNb1-yO3.Type: ApplicationFiled: October 4, 2006Publication date: November 1, 2007Applicant: Nippon Telegraph and Telephone CorporationInventors: Seiji Toyoda, Kazuo Fujiura, Masahiro Sasaura, Koji Enbutsu, Makoto Shimokozono, Tadayuki Imai, Akiyuki Tate, Touru Matsuura, Takashi Kurihara, Hiroshi Fushimi
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Publication number: 20070092181Abstract: An optical switch, an optical modulator, and a wavelength variable filter each have a simple configuration, which requires only a low driving voltage, which is independent of polarization, and which can operate at high speed. An optical switch includes a 3-dB coupler placed on an output, a 3-dB coupler placed on an output, and two optical waveguides connecting the input-side 3-dB coupler and the output-side 3-dB coupler together. The optical switch also includes a phase modulating section that applies electric fields to one or both of the two optical waveguides. At least two optical waveguides are a crystal material including KTaxNb1-xO3 (0<x<1) and KxLi1-xTayNb1-xO3 (0<x<1, 0<y<1), or KTaxNb1-xO3 or KxLi1-xTayNb1-yO3.Type: ApplicationFiled: October 4, 2006Publication date: April 26, 2007Applicant: Nippon Telegraph and Telephone CorporationInventors: Seiji Toyoda, Kazuo Fujiura, Masahiro Sasaura, Koji Enbutsu, Makoto Shimokozono, Tadayuki Imai, Akiyuki Tate, Touru Matsuura, Takashi Kurihara, Hiroshi Fushimi
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Publication number: 20070086691Abstract: An optical switch, an optical modulator, and a wavelength variable filter each have a simple configuration, which requires only a low driving voltage, which is independent of polarization, and which can operate at high speed. An optical switch includes a 3-dB coupler placed on an output, a 3-dB coupler placed on an output, and two optical waveguides connecting the input-side 3-dB coupler and the output-side 3-dB coupler together. The optical switch also includes a phase modulating section that applies electric fields to one or both of the two optical waveguides. At least two optical waveguides are a crystal material including KTaxNb1-xO3 (0<x<1) and KxLi1-xTayNb1-yO3 (0<x<2, 0<y<1), or KTaxNb1-xO3 or KxLi1-xTayNb1-yO3.Type: ApplicationFiled: October 4, 2006Publication date: April 19, 2007Applicant: Nippon Telegraph and Telephone CorporationInventors: Seiji Toyoda, Kazuo Fujiura, Masahiro Sasaura, Koji Enbutsu, Makoto Shimokozono, Tadayuki Imai, Akiyuki Tate, Touru Matsuura, Takashi Kurihara, Hiroshi Fushimi
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Publication number: 20070058896Abstract: The present invention provides an optical switch, an optical modulator, and a wavelength variable filter each of which has a simple configuration, which requires only a low driving voltage, which is independent of polarization, and which can operate at high speed. An optical switch according to the present invention includes a 3-dB coupler (16) placed on an output, a 3-dB coupler (17) placed on an output, and two optical waveguides connecting the input-side 3-dB coupler and the output-side 3-dB coupler together. The optical switch also includes a phase modulating section (18) that applies electric fields to one or both of the two optical waveguides. At least two optical waveguides are a crystal material including KTaxNb1-xO3 (0<x<1) and KxLi1-xTayNb1-yO3 (0<x<1, 0<y<1), or KTaxNb1-xO3 or KxLi1-xTayNb1-yO3.Type: ApplicationFiled: March 18, 2004Publication date: March 15, 2007Applicant: Nippon Telegraph and Telephone CorporationInventors: Seiji Toyoda, Kazuo Fujiura, Masahiro Sasaura, Koji Enbutsu, Makoto Shimokozono, Tadayuki Imai, Akiyuki Tate, Touru Matsuura, Takashi Kurihara, Hiroshi Fushimi
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Patent number: 7177514Abstract: The invention provides an optical waveguide material whose refractive index can be tailored without changing the ratio of Ta and Nb. An optical waveguide of this invention comprising an under-clad layer 1 and a core 2 that is formed on the under-clad layer 1 and has a higher refractive index than that of the under-clad layer 1 is shown. For example, KTN (KTa1?xNbxO3) is used as the core 2, and a material that is obtained by substituting at least one element selected from the group consisting of Zr, Hf, and Sn for a portion of one element of the constituent elements of KTN and has the same perovskite type crystal structure as KTN is used as the clad. The refractive index of KTN can be reduced considerably, and this controllability widens the degree of freedom in the design of optical waveguide devices.Type: GrantFiled: July 16, 2004Date of Patent: February 13, 2007Assignee: Nippon Telegraph and Telephone CorporationInventors: Tadayuki Imai, Kazuo Fujiura, Makoto Shimokozono, Seiji Toyoda, Masahiro Sasaura, Tohru Matsuura
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Publication number: 20060228089Abstract: A wavelength tunable optical filter (1) comprises a dielectric crystal portion (2) comprised of a dielectric crystal having a cubic system and exhibiting a quadratic electro-optic effect, a mirror portion (5, 6) constituting a Fabry-Perot etalon in cooperation with said dielectric crystal portion, and an electrode (3, 4) configured to apply a voltage to said dielectric crystal portion thereby to change a wavelength of light transmitting through said etalon on a basis of said electro-optic effect. According to the configuration, since the dielectric crystal having a cubic system and exhibiting a quadratic electro-optic effect is used, there is provided a wavelength tunable optical filter that is capable of operating at high-speed on application of a low voltage.Type: ApplicationFiled: June 11, 2004Publication date: October 12, 2006Inventors: Makoto Shimokozono, Kazuo Fujiura, Seiji Toyoda, Tadayuki Imai
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Publication number: 20060215981Abstract: The invention provides an optical waveguide material whose refractive index can be tailored without changing the ratio of Ta and Nb. An optical waveguide of this invention comprising an under-clad layer 1 and a core 2 that is formed on the under-clad layer 1 and has a higher refractive index than that of the under-clad layer 1 is shown. For example, KTN (KTa1?xNbxO3) is used as the core 2, and a material that is obtained by substituting at least one element selected from the group consisting of Zr, Hf, and Sn for a portion of one element of the constituent elements of KTN and has the same perovskite type crystal structure as KTN is used as the clad. The refractive index of KTN can be reduced considerably, and this controlability widens the degree of freedom in the design of optical waveguide devices.Type: ApplicationFiled: May 24, 2006Publication date: September 28, 2006Applicant: Nippon Telegraph and Telephone CorporationInventors: Tadayuki Imai, Kazuo Fujiura, Makoto Shimokozono, Seiji Toyoda, Masahiro Sasaura, Tohru Matsuura
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Publication number: 20060051041Abstract: The invention provides an optical waveguide material whose refractive index can be tailored without changing the ratio of Ta and Nb. An optical waveguide of this invention comprising an under-clad layer 1 and a core 2 that is formed on the under-clad layer 1 and has a higher refractive index than that of the under-clad layer 1 is shown. For example, KTN (KTa1?xNbxO3) is used as the core 2, and a material that is obtained by substituting at least one element selected from the group consisting of Zr, Hf, and Sn for a portion of one element of the constituent elements of KTN and has the same perovskite type crystal structure as KTN is used as the clad. The refractive index of KTN can be reduced considerably, and this controllability widens the degree of freedom in the design of optical waveguide devices.Type: ApplicationFiled: July 16, 2004Publication date: March 9, 2006Inventors: Tadayuki Imai, Kazuo Fujiura, Makoto Shimokozono, Seiji Toyoda, Masahiro Sasaura, Tohru Matsuura