Patents by Inventor Hiroyasu Mawatari
Hiroyasu Mawatari 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: 20210294176Abstract: The present invention provides a highly reliable, high-speed, and low-loss semiconductor optical modulation element that protects a pin junction structure in a modulation region against reverse voltage ESD by configuring an additional capacity having a thyristor structure between a plurality of feeding pad electrodes. An n-type contact layer, an n-type cladding layer, a non-doped core/cladding layer, a p-type cladding layer, and a p-type contact layer are sequentially laminated on the substrate surface. A Mach-Zehnder interferometric waveguide and a plurality of feeding pad installation sections are formed by dry etching. The n-type contact layer and the n-type cladding layer are removed except for a modulation region of the Mach-Zehnder interferometric waveguide and a feeding region in which the feeding pad installation sections are formed so that the modulation region and the semiconductor of the lower part of the feeding region are electrically isolated from each other.Type: ApplicationFiled: September 13, 2017Publication date: September 23, 2021Inventors: Yoshihiro OGISO, Hiroyasu MAWATARI, Nobuhiro KIKUCHI
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Patent number: 11126058Abstract: The present invention provides a highly reliable, high-speed, and low-loss semiconductor optical modulation element that protects a pin junction structure in a modulation region against reverse voltage ESD by configuring an additional capacity having a thyristor structure between a plurality of feeding pad electrodes. An n-type contact layer, an n-type cladding layer, a non-doped core/cladding layer, a p-type cladding layer, and a p-type contact layer are sequentially laminated on the substrate surface. A Mach-Zehnder interferometric waveguide and a plurality of feeding pad installation sections are formed by dry etching. The n-type contact layer and the n-type cladding layer are removed except for a modulation region of the Mach-Zehnder interferometric waveguide and a feeding region in which the feeding pad installation sections are formed so that the modulation region and the semiconductor of the lower part of the feeding region are electrically isolated from each other.Type: GrantFiled: September 13, 2017Date of Patent: September 21, 2021Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Yoshihiro Ogiso, Hiroyasu Mawatari, Nobuhiro Kikuchi
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Patent number: 7729585Abstract: A light source apparatus with modulation function has a wavelength conversion module (75) composed of a nonlinear optical material with a structure having a nonlinear constant modulated periodically. It outputs a difference frequency or sum frequency produced by multiplexing pumping light from semiconductor laser light sources (71) and (72) with different wavelengths through a WDM coupler (74) and by launching the multiplexed light into the optical waveguide. The semiconductor laser light source (72) includes a diffraction grating. The semiconductor laser light source (71) includes a section for modulating output light emitted from its semiconductor laser, and is connected to an external FBG (73) which has a reflection band narrower than a resonance wavelength spacing determined by the device length of the semiconductor laser. The FBG (73) is supplied with the modulated output.Type: GrantFiled: January 17, 2006Date of Patent: June 1, 2010Assignees: NipponTelegraph and Telephone Corporation, NTT Electronics CorporationInventors: Katsuaki Magari, Tsutomu Yanagawa, Yoshiki Nishida, Hiroyasu Mawatari, Osamu Tadanaga, Masaki Asobe, Hiroyuki Suzuki, Hiroshi Miyazawa, Junji Yumoto
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Publication number: 20100053720Abstract: A light source apparatus with modulation function has a wavelength conversion module (75) composed of a nonlinear optical material with a structure having a nonlinear constant modulated periodically. It outputs a difference frequency or sum frequency produced by multiplexing pumping light from semiconductor laser light sources (71) and (72) with different wavelengths through a WDM coupler (74) and by launching the multiplexed light into the optical waveguide. The semiconductor laser light source (72) includes a diffraction grating. The semiconductor laser light source (71) includes a section for modulating output light emitted from its semiconductor laser, and is connected to an external FBG (73) which has a reflection band narrower than a resonance wavelength spacing determined by the device length of the semiconductor laser. The FBG (73) is supplied with the modulated output.Type: ApplicationFiled: January 17, 2006Publication date: March 4, 2010Applicants: Nippon Telegraph and Telephone Corporation, NTT Electronics Corporation,Inventors: Katsuaki Magari, Tsutomu Yanagawa, Yoshiki Nishida, Hiroyasu Mawatari, Osamu Tadanaga, Masaki Asobe, Hiroyuki Suzuki, Hiroshi Miyazawa, Junji Yumoto
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Patent number: 7573921Abstract: A laser light source is disclosed consisting of first and second lasers that respectively generate laser beams of wavelengths ?1 and ?2. Wavelength ?1 is in the range of 0.9-1.0 ?m. A nonlinear optical crystal uses the laser beams of wavelengths ?1 and ?2 as inputs, and outputs a coherent beam having a wavelength ?3 of a difference frequency that satisfies a relationship of 1/?1?1/?2=1/?3. The nonlinear optical crystal has a periodically poled structure of a single period. The wavelength ?3 of the difference frequency varies between 3.1 ?m and 2.0 ?m when the wavelength ?2 varies between 1.3 ?m and 1.8 ?m.Type: GrantFiled: August 15, 2007Date of Patent: August 11, 2009Assignee: Nippon Telegraph and Telephone CorporationInventors: Junji Yumoto, Osamu Tadanaga, Masaki Asobe, Hiroyuki Suzuki, Kaoru Yoshino, Hiroshi Miyazawa, Yoshiki Nishida, Hirohisa Kanbara, Tsutomu Yanagawa, Eishi Kubota, Hiroyasu Mawatari
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Publication number: 20090022903Abstract: The present invention provides a periodically-poled structure with high conversion efficiency and improved manufacturing yield. The method for manufacturing a periodically-poled structure in a second order nonlinear optical crystal having a single domain structure (31) includes the steps of forming a resist pattern (32) which matches a polarization-inverted period on a ?Z surface of the second order nonlinear optical crystal (31), and applying voltage to the ?Z surface as a negative voltage where the resist pattern (32) is formed, and a +Z surface as a positive voltage so as to apply an electric field in the second order nonlinear optical crystal (31), wherein the second order nonlinear optical crystal (31) contains at least one element as a dopant which compensate for the crystal defects.Type: ApplicationFiled: March 17, 2006Publication date: January 22, 2009Inventors: Hiroyuki Suzuki, Masaki Asobe, Takeshi Umeki, Yoshiki Nishida, Osamu Tadanaga, Tsutomu Yanagawa, Katsuaki Magari, Hiroyasu Mawatari, Hiroshi Miyazawa, Junji Yumoto
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Patent number: 7391795Abstract: The invention provides a compact laser light source whose wavelength can be designed freely in a wavelength band in which the semiconductor laser has not been put to practical use by combining an efficient nonlinear optical crystal and high-power semiconductor lasers for optical communication. In one embodiment, the laser light source includes: a first laser for generating a laser beam of a wavelength ?1; a second laser for generating a laser beam of a wavelength ?2; and a nonlinear optical crystal that allows the laser beam of wavelength ?1 and the laser beam of wavelength ?2 as inputs and outputs a coherent beam having a wavelength ?3 of a sum frequency that satisfies a relationship of 1/?1+1/?2=1/?3. The wavelength ?3 of the sum frequency is 589.3±2 nm that is equivalent to the sodium D line.Type: GrantFiled: July 30, 2004Date of Patent: June 24, 2008Assignee: Nippon Telegraph and Telephone CorporationInventors: Junji Yumoto, Osamu Tadanaga, Masaki Asobe, Hiroyuki Suzuki, Kaoru Yoshino, Hiroshi Miyazawa, Yoshiki Nishida, Hirohisa Kanbara, Tsutomu Yanagawa, Eishi Kubota, Hiroyasu Mawatari
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Publication number: 20070297465Abstract: A laser light source is disclosed consisting of first and second lasers that respectively generate laser beams of wavelengths ?1 and ?2. Wavelength ?1 is in the range of 0.9-1.0 ?m. A nonlinear optical crystal uses the laser beams of wavelengths ?1 and ?2 as inputs, and outputs a coherent beam having a wavelength ?3 of a difference frequency that satisfies a relationship of 1/?1?1/?2=1/?3. The nonlinear optical crystal has a periodically poled structure of a single period. The wavelength ?3 of the difference frequency varies between 3.1 ?m and 2.0 ?m when the wavelength ?2 varies between 1.3 ?m and 1.8 ?m.Type: ApplicationFiled: August 15, 2007Publication date: December 27, 2007Applicant: Nippon Telegraph and Telephone CorporationInventors: Junji Yumoto, Osamu Tadanaga, Masaki Asobe, Hiroyuki Suzuki, Kaoru Yoshino, Hiroshi Miyazawa, Yoshiki Nishida, Hirohisa Kanbara, Tsutomu Yanagawa, Eishi Kubota, Hiroyasu Mawatari
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Publication number: 20060013270Abstract: The invention provides a compact laser light source whose wavelength can be designed freely in a wavelength band in which the semiconductor laser has not been put to practical use by combining an efficient nonlinear optical crystal and high-power semiconductor lasers for optical communication. In one embodiment, the laser light source includes: a first laser for generating a laser beam of a wavelength ?1; a second laser for generating a laser beam of a wavelength ?2; and a nonlinear optical crystal that allows the laser beam of wavelength ?1 and the laser beam of wavelength ?2 as inputs and outputs a coherent beam having a wavelength ?3 of a sum frequency that satisfies a relationship of 1/?1+1/?2=1/?3. The wavelength ?3 of the sum frequency is 589.3±2 nm that is equivalent to the sodium D line.Type: ApplicationFiled: July 30, 2004Publication date: January 19, 2006Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Junji Yumoto, Osamu Tadanaga, Masaki Asobe, Hiroyuki Suzuki, Kaoru Yoshino, Hiroshi Miyazawa, Yoshiki Nishida, Hirohisa Kanbara, Tsutomu Yanagawa, Eishi Kubota, Hiroyasu Mawatari