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公开(公告)号:US11054675B2
公开(公告)日:2021-07-06
申请号:US16645377
申请日:2018-08-24
Inventor: Junichi Fujikata , Shigeki Takahashi , Mitsuru Takenaka
Abstract: Provided is an optical modulator which is small in optical loss, is small in a size, and is low in required voltage and is operable to perform high-speed operation. The optical phase modulator 100 comprises a rib-type waveguide structure 110 including: a PN junction 106 which is formed of Si and is formed in a lateral direction on a substrate; and an Si1-xGex layer 108 which is constituted of at least one layer and is doped with an impurity to a p-type and is superposed on the PN junction 106 so as to be electrically connected to the PN junction 106. The rib-type waveguide structure 110 has a substantially uniform structure along a light propagation direction, and in a direction parallel with the substrate and perpendicular to the light propagation direction, a position of a junction interface 106a of the PN junction 106 is offset from a center of the Si1-xGex layer 108.
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公开(公告)号:US20200301177A1
公开(公告)日:2020-09-24
申请号:US16645377
申请日:2018-08-24
Inventor: Junichi Fujikata , Shigeki Takahashi , Mitsuru Takenaka
IPC: G02F1/025
Abstract: Provided is an optical modulator which is small in optical loss, is small in a size, and is low in required voltage and is operable to perform high-speed operation. The optical phase modulator 100 comprises a rib-type waveguide structure 110 including: a PN junction 106 which is formed of Si and is formed in a lateral direction on a substrate; and an Si1-xGex layer 108 which is constituted of at least one layer and is doped with an impurity to a p-type and is superposed on the PN junction 106 so as to be electrically connected to the PN junction 106. The rib-type waveguide structure 110 has a substantially uniform structure along a light propagation direction, and in a direction parallel with the substrate and perpendicular to the light propagation direction, a position of a junction interface 106a of the PN junction 106 is offset from a center of the Si1-xGex layer 108.
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公开(公告)号:US10340399B2
公开(公告)日:2019-07-02
申请号:US15748994
申请日:2016-07-28
Inventor: Shigekazu Okumura , Tohru Mogami , Keizo Kinoshita , Tsuyoshi Horikawa , Junichi Fujikata
IPC: H01L31/028 , H01L31/036 , H01L31/102 , H01L31/105 , H01L31/109 , H01L31/0232
Abstract: Provided is an optical device in which an Si cap layer is provided on a Ge layer, and which is capable of effectively reducing dark current, while having a good effect on prevention of production line contamination by Ge. One embodiment of the optical device according to the present invention is provided with: a semiconductor layer which contains Ge and has a (001) surface and a facet surface between the (001) surface and a (110) surface; and a cap layer which is formed from Si, and which is formed on the (001) surface and the facet surface of the semiconductor layer. The ratio of the film thickness of the cap layer on the facet surface to the film thickness of the cap layer on the (001) surface is 0.4 or more; and the film thickness of the cap layer on the (001) surface is from 9 nm to 30 nm (inclusive).
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公开(公告)号:US11009726B2
公开(公告)日:2021-05-18
申请号:US16354886
申请日:2019-03-15
Inventor: Junichi Fujikata
Abstract: An electro-absorption optical modulator capable of realizing optical coupling with a Si waveguide with high efficiency, improving modulation efficiency, reducing light absorption by an electrode layer and achieving low optical loss includes a substrate; a first silicon layer doped to exhibit a first type of conductivity and a second silicon layer doped to exhibit a second type of conductivity that are disposed parallel to the substrate; and a Ge1−xSix (0
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公开(公告)号:US20200313021A1
公开(公告)日:2020-10-01
申请号:US16817152
申请日:2020-03-12
Inventor: Junichi Fujikata
IPC: H01L31/105 , H01L31/0352 , H01L31/0232
Abstract: A photodetector which can perform high-speed operation and make the manufacturing process thereof easy is provided. A photodetector 400 comprises an Si layer including a lateral pin junction structure, and a light absorbing layer stacked on the lateral pin junction structure. At least part of an upper part of the light absorbing layer is doped to exhibit a first conductivity type. At least part of a side wall of the light absorbing layer is doped to exhibit the first conductivity type, for making the at least part of the upper part of the light absorbing layer to be electrically connected to a region of the first conductivity type in the lateral pin junction structure.
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公开(公告)号:US10274757B2
公开(公告)日:2019-04-30
申请号:US15559911
申请日:2016-02-17
Inventor: Junichi Fujikata , Shigeki Takahashi
Abstract: An electro-optic device includes a first semiconductor layer including the rib-type waveguide, which includes a rib part and a first slab part, which extends in a first direction from the rib part; a dielectric layer, which is formed on the rib part; a second semiconductor layer, which extends in a second direction, which is opposite to the first direction, from an upper surface of the dielectric layer; a first high-concentration impurity region, which is formed in the first semiconductor layer to be in contact with the first slab part on the first direction side; and a second high-concentration impurity region, which is formed in a region of the second semiconductor layer on the second direction side. The second high-concentration impurity region is formed in a region other than a region overlapping the first semiconductor layer in a lamination direction.
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公开(公告)号:US10146070B2
公开(公告)日:2018-12-04
申请号:US15548687
申请日:2016-02-02
Inventor: Junichi Fujikata , Shigeki Takahashi , Mitsuru Takenaka , Younghyun Kim
Abstract: An optical phase modulator 100 according to an embodiment of this disclosure comprises a rib-type waveguide structure 110 comprising: a PN junction 106 comprising Si and formed in a lateral direction on a substrate; and a Si1-xGex layer 108 that is doped with a p-type impurity and comprises at least one layer laminated on the PN junction 106, so as to be electrically connected to the PN junction 106.
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公开(公告)号:US09897752B2
公开(公告)日:2018-02-20
申请号:US14780434
申请日:2014-03-20
Inventor: Shigeki Takahashi , Junichi Fujikata
CPC classification number: G02B6/1228 , G02B6/122 , G02B6/14 , G02B6/2813 , G02B6/305
Abstract: An optical end coupling type silicon optical integrated circuit is provided using an SOI substrate. This optical integrated circuit is constituted so as to connect with an external optical circuit at an end coupling part and have signal light incident to an optical circuit that includes a curved part. In the plane of the optical integrated circuit, the position of one end coupling part selected from among any thereof and the position of any multimode optical waveguide element to which a respective optical waveguide is connected via a respective curved part satisfy a positional relationship defined on the basis of a beam divergence angle [theta] of stray light.
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公开(公告)号:US20160041338A1
公开(公告)日:2016-02-11
申请号:US14780434
申请日:2014-03-20
Inventor: Shigeki Takahashi , Junichi Fujikata
CPC classification number: G02B6/1228 , G02B6/122 , G02B6/14 , G02B6/2813 , G02B6/305
Abstract: An optical end coupling type silicon optical integrated circuit is provided using an SOI substrate. This optical integrated circuit is constituted so as to connect with an external optical circuit at an end coupling part and have signal light incident to an optical circuit that includes a curved part. In the plane of the optical integrated circuit, the position of one end coupling part selected from among any thereof and the position of any multimode optical waveguide element to which a respective optical waveguide is connected via a respective curved part satisfy a positional relationship defined on the basis of a beam divergence angle [theta] of stray light.
Abstract translation: 使用SOI衬底提供光端耦合型硅光集成电路。 该光集成电路构成为与端部耦合部分的外部光电路连接,并且具有入射到包括弯曲部分的光学电路的信号光。 在光集成电路的平面中,从其任意一个中选择的一端耦合部分的位置和通过相应的弯曲部分连接有相应光波导的任何多模光波导元件的位置满足定义在 杂散光的光束发散角θ的基础。
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公开(公告)号:US10996539B2
公开(公告)日:2021-05-04
申请号:US16440407
申请日:2019-06-13
Inventor: Shigeki Takahashi , Junichi Fujikata
Abstract: Provided is a SIS-type electro-optic modulator capable of realizing highly efficient optical coupling with a rib-type Si waveguide, improving modulation efficiency, realizing reduction of electric capacity and lead-out resistance in stacked semiconductor layers. The modulator includes a SIS junction constituted by first and second semiconductor layers having different type of conductivity and a dielectric layer interposed therebetween, wherein an electrical signal from electrodes coupled to the first and second semiconductor layers causes free carriers accumulate, deplete or invert on both sides of the dielectric layer, thereby modulating a free carrier concentration felt by an optical signal electric filed, light having a polarization component orthogonal to the width direction of the SIS junction is incident on the dielectric layer, and the width of the SIS junction is λ/neff or less (λ is the wavelength of the incident light and neff is an effective refractive index of the modulator to the incident light).
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