Patents by Inventor Nozomu Yasuhara
Nozomu Yasuhara 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: 10771161Abstract: Provided is an optical transmission module which can generate PAM4 optical modulation signals without converting a plurality of binary electric signals to a multi-level electric signal. An optical transmission module (200) comprising: a light source (60) for emitting continuous waveform (CW) light; optical modulators (51,52,53) arranged in series with a path of the CW light configured to modulate the CW light by switching relatively large absorption and relatively small absorption of the optical modulators in response to a modulation signal applied to the respective optical modulators; and an arithmetic logic circuit (100) configured to receive a plurality of binary electrical signals, and then to perform logic operation on the plurality of binary electrical signals for generating a new plurality of binary electrical signals, wherein each of the new plurality of binary electrical signals is applied to the respective optical modulators as the modulation signal.Type: GrantFiled: December 7, 2017Date of Patent: September 8, 2020Assignee: Lumentum Japan, Inc.Inventors: Atsushi Nakamura, Shunya Yamauchi, Yoriyoshi Yamaguchi, Nozomu Yasuhara, Yoshihiro Nakai, Hideaki Asakura, Noriko Sasada, Takayoshi Fukui, Hiroki Irie
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Publication number: 20190028204Abstract: Provided is an optical transmission module which can generate PAM4 optical modulation signals without converting a plurality of binary electric signals to a multi-level electric signal. An optical transmission module (200) comprising: a light source (60) for emitting continuous waveform (CW) light; optical modulators (51,52,53) arranged in series with a path of the CW light configured to modulate the CW light by switching relatively large absorption and relatively small absorption of the optical modulators in response to a modulation signal applied to the respective optical modulators; and an arithmetic logic circuit (100) configured to receive a plurality of binary electrical signals, and then to perform logic operation on the plurality of binary electrical signals for generating a new plurality of binary electrical signals, wherein each of the new plurality of binary electrical signals is applied to the respective optical modulators as the modulation signal.Type: ApplicationFiled: December 7, 2017Publication date: January 24, 2019Inventors: Atsushi NAKAMURA, Shunya YAMAUCHI, Yoriyoshi YAMAGUCHI, Nozomu YASUHARA, Yoshihiro NAKAI, Hideaki ASAKURA, Noriko SASADA, Takayoshi FUKUI, Hiroki IRIE
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Patent number: 10063029Abstract: Provided is an optical transmission module in which noise is further reduced. The optical transmission module includes a first semiconductor layer having a first electrode arranged thereon, an active layer with a stripe shape formed on the first semiconductor layer, and a second semiconductor layer with a stripe shape formed on the active layer. The second semiconductor layer has a second electrode arranged thereon and includes a diffraction grating arranged along an extending direction of the active layer. The active layer includes a first portion having first stripe width, a second portion having a second stripe width smaller than the first stripe width, and a connection portion having a varying stripe width so as to connect the first portion and the second portion to each other. The diffraction grating overlaps with the first portion and does not overlap with the second portion in planar view.Type: GrantFiled: February 27, 2017Date of Patent: August 28, 2018Assignee: Oclaro Japan, Inc.Inventors: Atsushi Nakamura, Nozomu Yasuhara, Shunya Yamauchi, Yoriyoshi Yamaguchi, Yoshihiro Nakai
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Patent number: 9806821Abstract: Multilevel optical intensity modulation high in accuracy is performed using electro-absorption optical modulators. There is provided a plurality of EA modulators connected in series in a path of an optical signal from a light source, and a multilevel-coded modulated optical signal is generated by modulating an intensity of an input optical signal from the light source based on a modulation signal using the EA modulators. Each of the EA modulators is switched between an ON state and an OFF state of optical absorption in accordance with the modulation signal. Regarding an extinction ratio of the ON state to the OFF state in each of the EA modulators, the EA modulators have respective values difference from each other, and are arranged in ascending order of the extinction ratio from the light source side.Type: GrantFiled: June 1, 2016Date of Patent: October 31, 2017Assignee: OCLARO JAPAN, INC.Inventors: Atsushi Nakamura, Shunya Yamauchi, Yoriyoshi Yamaguchi, Noriko Sasada, Nozomu Yasuhara, Takayoshi Fukui, Hiroki Irie
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Publication number: 20170250521Abstract: Provided is an optical transmission module in which noise is further reduced. The optical transmission module includes a first semiconductor layer having a first electrode arranged thereon, an active layer with a stripe shape formed on the first semiconductor layer, and a second semiconductor layer with a stripe shape formed on the active layer. The second semiconductor layer has a second electrode arranged thereon and includes a diffraction grating arranged along an extending direction of the active layer. The active layer includes a first portion having first stripe width, a second portion having a second stripe width smaller than the first stripe width, and a connection portion having a varying stripe width so as to connect the first portion and the second portion to each other. The diffraction grating overlaps with the first portion and does not overlap with the second portion in planar view.Type: ApplicationFiled: February 27, 2017Publication date: August 31, 2017Inventors: Atsushi NAKAMURA, Nozomu YASUHARA, Shunya YAMAUCHI, Yoriyoshi YAMAGUCHI, Yoshihiro NAKAI
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Patent number: 9726914Abstract: Preferable simultaneous achievement of the target characteristics with respect to both of the modulation bandwidth and the extinction ratio in the optical intensity modulation using the electro-absorption optical modulator is realized with a simple circuit configuration. The modulator integrated semiconductor laser element includes a plurality of EA modulators disposed in series in an optical signal path, and each adapted to absorb light in accordance with an applied voltage. The modulator driver for supplying the EA modulator with the applied voltage is provided for each of the EA modulators. The plurality of modulator drivers generates the applied voltage common to the plurality of EA modulators in accordance with a control signal. The modulator lengths of the plurality of EA modulators are set so that the closer to the light source the EA modulator is, the shorter the modulator length is.Type: GrantFiled: June 6, 2016Date of Patent: August 8, 2017Assignee: OCLARO JAPAN, INC.Inventors: Atsushi Nakamura, Shunya Yamauchi, Noriko Sasada, Takayoshi Fukui, Nozomu Yasuhara
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Publication number: 20160370609Abstract: Preferable simultaneous achievement of the target characteristics with respect to both of the modulation bandwidth and the extinction ratio in the optical intensity modulation using the electro-absorption optical modulator is realized with a simple circuit configuration. The modulator integrated semiconductor laser element includes a plurality of EA modulators disposed in series in an optical signal path, and each adapted to absorb light in accordance with an applied voltage. The modulator driver for supplying the EA modulator with the applied voltage is provided for each of the EA modulators. The plurality of modulator drivers generates the applied voltage common to the plurality of EA modulators in accordance with a control signal. The modulator lengths of the plurality of EA modulators are set so that the closer to the light source the EA modulator is, the shorter the modulator length is.Type: ApplicationFiled: June 6, 2016Publication date: December 22, 2016Inventors: Atsushi NAKAMURA, Shunya YAMAUCHI, Noriko SASADA, Takayoshi FUKUI, Nozomu YASUHARA
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Publication number: 20160365929Abstract: Multilevel optical intensity modulation high in accuracy is performed using electro-absorption optical modulators. There is provided a plurality of EA modulators connected in series in a path of an optical signal from a light source, and a multilevel-coded modulated optical signal is generated by modulating an intensity of an input optical signal from the light source based on a modulation signal using the EA modulators. Each of the EA modulators is switched between an ON state and an OFF state of optical absorption in accordance with the modulation signal. Regarding an extinction ratio of the ON state to the OFF state in each of the EA modulators, the EA modulators have respective values difference from each other, and are arranged in ascending order of the extinction ratio from the light source side.Type: ApplicationFiled: June 1, 2016Publication date: December 15, 2016Inventors: Atsushi NAKAMURA, Shunya YAMAUCHI, Yoriyoshi YAMAGUCHI, Noriko SASADA, Nozomu YASUHARA, Takayoshi FUKUI, Hiroki IRIE
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Patent number: 8610105Abstract: Provided is a semiconductor electroluminescent device with an InGaAlAs-based well layer having tensile strain, or a semiconductor electroluminescent device with an InGaAsP-based well layer having tensile strain and with an InGaAlAs-based barrier layer which is high-performance and highly reliable in a wide temperature range. In a multiple-quantum well layer of the semiconductor electroluminescent device, a magnitude of interface strain at an interface between the well layer and the barrier layer is smaller than a magnitude of critical interface strain determined by a layer thickness value which is larger one of a thickness of the well layer and a thickness of the barrier layer.Type: GrantFiled: November 9, 2009Date of Patent: December 17, 2013Assignee: Oclaro Japan, Inc.Inventors: Toshihiko Fukamachi, Takashi Shiota, Takeshi Kitatani, Nozomu Yasuhara, Atsushi Nakamura, Mitsuhiro Sawada
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Publication number: 20100288997Abstract: Provided is a semiconductor electroluminescent device with an InGaAlAs-based well layer having tensile strain, or a semiconductor electroluminescent device with an InGaAsP-based well layer having tensile strain and with an InGaAlAs-based barrier layer which is high-performance and highly reliable in a wide temperature range. In a multiple-quantum well layer of the semiconductor electroluminescent device, a magnitude of interface strain at an interface between the well layer and the barrier layer is smaller than a magnitude of critical interface strain determined by a layer thickness value which is larger one of a thickness of the well layer and a thickness of the barrier layer.Type: ApplicationFiled: November 9, 2009Publication date: November 18, 2010Inventors: Toshihiko FUKAMACHI, Takashi Shiota, Takeshi Kitatani, Nozomu Yasuhara, Atsushi Nakamura, Mitsuhiro Sawada