Patents by Inventor Jun Ushida
Jun Ushida 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).
-
Publication number: 20130064491Abstract: To provide an optical modulator having a reduced size and reduced power consumption and capable of being easily connected to a waveguide and a method of manufacturing the optical modulator. The optical modulator has at least semiconductor layer (8) having a rib-shaped portion and doped so as to be of a first conduction type, dielectric layer (11) laid on first-conduction-type semiconductor layer (8), and semiconductor layer (9) laid on dielectric layer (11), having the width at the side opposite from dielectric layer (11) increased relative to the width of the rib-shaped portion, and doped so as to be of a second conduction type.Type: ApplicationFiled: March 1, 2011Publication date: March 14, 2013Applicant: NEC CORPORATIONInventors: Junichi Fujikata, Motofumi Saitoh, Jun Ushida, Akio Toda
-
Patent number: 8363989Abstract: Provided is a semiconductor optical interconnection device capable of transmitting signals between laminated semiconductor chips in a structure where semiconductor chips highly functionalized by being bonded to an optical interconnection chip are laminated. The semiconductor optical interconnection device includes a semiconductor chip 1 and an optical interconnection chip 2. The optical interconnection chip 2 includes an optical element formed thereon (for instance, a photo-sensitive element, a luminous element, or an optical modulator) which has a function relating to signal conversion between light and electricity. The semiconductor chip 1 includes a transmission section 3 (for instance, a coil or an inductor) to transmit signals in a non-contact manner, and a connection section 4 (for instance, a bump) to electrically connect with the optical element.Type: GrantFiled: February 10, 2009Date of Patent: January 29, 2013Assignee: NEC CorporationInventors: Daisuke Okamoto, Kenichi Nishi, Junichi Fujikata, Jun Ushida
-
Publication number: 20120257850Abstract: A downsized, low-power electro-optical modulator that achieves reducing both of the additional resistance in the modulation portion and the optical loss each caused by electrodes at the same time is provided. The electro-optical modulator includes a rib waveguide formed by stacking a second semiconductor layer 9 having a different conductivity type from a first semiconductor layer 8 on the first semiconductor layer 8 via a dielectric film 11, and the semiconductor layers 8 and 9 are connectable to an external terminal via highly-doped portions 4 and 10, respectively. In a region in the vicinity of contact surfaces of the semiconductor layers 8 and 9 with the dielectric film 11, a free carrier is accumulated, removed, or inverted by an electrical signal from the external terminal, and whereby a concentration of the free carrier in an electric field region of an optical signal is modulated, so that a phase of the optical signal can be modulated.Type: ApplicationFiled: June 8, 2010Publication date: October 11, 2012Applicant: NEC CORPORATIONInventors: Junichi Fujikata, Jun Ushida, Akio Toda, Motofumi Saitoh
-
Patent number: 8269303Abstract: The lattice mismatching between a Ge layer and a Si layer is as large as about 4%. Thus, when the Ge layer is grown on the Si layer, penetration dislocation is introduced to cause leakage current at the p-i-n junction. Thereby, the photo-detection sensitivity is reduced, and the reliability of the element is also lowered. Further, in the connection with a Si waveguide, there are also problems of the reflection loss due to the difference in refractive index between Si and Ge, and of the absorption loss caused by a metal electrode.Type: GrantFiled: March 9, 2009Date of Patent: September 18, 2012Assignee: NEC CorporationInventors: Junichi Fujikata, Toru Tatsumi, Akihito Tanabe, Jun Ushida, Daisuke Okamoto, Kenichi Nishi
-
Publication number: 20120134633Abstract: Provided is a connecting channel that has manufacturing tolerance, can suppress light loses, improves reliability of the connecting channel, and connects an optical device and an optical waveguide. The connecting channel includes first silicon layer (3) that has rib-shaped part (3?) extending in a longitudinal direction of the connecting channel, and second silicon layer (6) that is stacked on first silicon layer (3) to partially overlap rib-shaped part 3?, and extends in the longitudinal direction. Second silicon layer (6) has tapered part (W) tapered toward one end in the longitudinal direction, and is located away from an upper portion of rib-shaped part (3?) at an end surface of one end in the longitudinal direction.Type: ApplicationFiled: April 14, 2010Publication date: May 31, 2012Inventors: Jun Ushida, Junichi Fujikata
-
Publication number: 20120003767Abstract: An optical modulator according to the present invention is configured at least by a semiconductor layer subjected to a doping process so as to exhibit a first conductivity type, and a semiconductor layer subjected to a doping process so as to exhibit a second conductivity type. Further, in the optical modulator, at least the first conductivity type semiconductor layer, a dielectric layer, the second conductivity type semiconductor layer, and a transparent electrode optically transparent in at least a near-infrared wavelength region are laminated in order.Type: ApplicationFiled: February 15, 2010Publication date: January 5, 2012Applicant: NEC CORPORATIONInventors: Junichi Fujikata, Toshio Baba, Jun Ushida
-
Publication number: 20110311178Abstract: The components are a lower clad layer (102), a first silicon layer (103) that is formed on the lower clad layer (102) as a single body made of silicon of a first conduction type and has a slab region (105) that is disposed at a core (104) and on both sides of the core (104) and connects to the core, a concave section (104a) that is formed in the top surface of the core (104), and a second silicon layer (109) of a second conduction type that is formed inside the concave section (104a) with an intervening dielectric layer (108) to fill the inside of the concave section (104a).Type: ApplicationFiled: February 18, 2010Publication date: December 22, 2011Applicant: NEC CORPORATIONInventors: Junichi Fujikata, Jun Ushida, Akio Toda, Motofumi Saitoh
-
Patent number: 8078021Abstract: A waveguide connecting structure includes a light branching element (111) for branching light from an input optical waveguide (201) including one core into two branched light components having the same optical power and the same phase, and a twin-arm waveguide (113) including a pair of arm waveguides (113A, 113B) for outputting the light components branched by the light branching element to a slot waveguide (202) including two cores arranged in parallel at a narrow spacing. The pair of arm waveguides have cores formed in a cladding on a substrate and having a refractive index higher than that of the cladding, and are formed such that the spacing between them gradually narrows and becomes equal to the core spacing of the slot waveguide from the core input ends into which the branched light components enter toward the core output ends from which the light components are output to the slot waveguide.Type: GrantFiled: December 12, 2007Date of Patent: December 13, 2011Assignee: NEC CorporationInventor: Jun Ushida
-
Publication number: 20110211786Abstract: In an electro-optic device, a stack structure including a first silicon layer of a first conductivity type and a second silicon layer of a second conductivity type has a rib waveguide shape so as to form an optical confinement area, and a slab portion of a rib waveguide includes an area to which a metal electrode is connected. The slab portion in the area to which the metal electrode is connected is thicker than a surrounding slab portion. The area to which the metal electrode is connected is set so that a range of a distance from the rib waveguide to the area to which the metal electrode is connected is such that when the distance is changed, an effective refractive index of the rib waveguide in a zeroth-order mode does not change.Type: ApplicationFiled: February 28, 2011Publication date: September 1, 2011Applicants: NEC CORPORATION, AGENCY FOR SCIENCE, TECHNOLOGY AND RESEARCHInventors: Jun USHIDA, Junichi FUJIKATA, Ming-Bin YU, Liang DING, ShiYang ZHU
-
Publication number: 20110176762Abstract: An optical modulator is formed with at least a portion of a semiconductor layer (8) that has undergone a doping process to exhibit a first conductivity and at least a portion of a semiconductor layer (9) that has undergone a doping process to exhibit a second conductivity overlapping with a dielectric layer (11) interposed. The surface of the semiconductor layer (8) of first conductivity has an uneven form in the portion in which the semiconductor layer (8) that exhibits first conductivity and the semiconductor layer (9) that exhibits second conductivity overlap with the dielectric layer (11) interposed. The dielectric layer (11) is formed on the semiconductor layer (8) of first conductivity that has the uneven form, and the semiconductor layer (9) of second conductivity is formed on the dielectric layer (11).Type: ApplicationFiled: November 10, 2009Publication date: July 21, 2011Inventors: Junichi Fujikata, Toshio Baba, Jun Ushida
-
Publication number: 20110012221Abstract: The lattice mismatching between a Ge layer and a Si layer is as large as about 4%. Thus, when the Ge layer is grown on the Si layer, penetration dislocation is introduced to cause leakage current at the p-i-n junction. Thereby, the photo-detection sensitivity is reduced, and the reliability of the element is also lowered. Further, in the connection with a Si waveguide, there are also problems of the reflection loss due to the difference in refractive index between Si and Ge, and of the absorption loss caused by a metal electrode.Type: ApplicationFiled: March 9, 2009Publication date: January 20, 2011Inventors: Junichi Fujikata, Toru Tatsumi, Akihito Tanabe, Jun Ushida, Daisuke Okamoto, Kenichi Nishi
-
Publication number: 20110002582Abstract: Provided is a semiconductor optical interconnection device capable of transmitting signals between laminated semiconductor chips in a structure where semiconductor chips highly functionalized by being bonded to an optical interconnection chip are laminated. The semiconductor optical interconnection device includes a semiconductor chip 1 and an optical interconnection chip 2. The optical interconnection chip 2 includes an optical element formed thereon (for instance, a photo-sensitive element, a luminous element, or an optical modulator) which has a function relating to signal conversion between light and electricity. The semiconductor chip 1 includes a transmission section 3 (for instance, a coil or an inductor) to transmit signals in a non-contact manner, and a connection section 4 (for instance, a bump) to electrically connect with the optical element.Type: ApplicationFiled: February 10, 2009Publication date: January 6, 2011Inventors: Daisuke Okamoto, Kenichi Nishi, Junichi Fujikata, Jun Ushida
-
Publication number: 20100320496Abstract: A semiconductor device comprises a semiconductor layer having a semiconductor integrated circuit, which is for processing an electrical signal, on a semiconductor substrate and an optical interconnect layer for transmitting an optical signal are joined. Control of modulation of the optical signal transmitted in the optical interconnect layer is performed by an electrical signal from the semiconductor layer, and an electrical signal generated by reception of light in the optical interconnect layer is transmitted to the semiconductor layer. The optical interconnect layer is disposed on the underside of the semiconductor substrate.Type: ApplicationFiled: February 26, 2009Publication date: December 23, 2010Inventors: Kenichi Nishi, Junichi Fujikata, Jun Ushida, Daisuke Okamoto
-
Patent number: 7778509Abstract: Disclosed in a method and a device in which a wave number of light in the waveguide mode of a photonic crystal optical waveguide is matched with that of the incident light, or a intensity ratio of electric field to magnetic field of the light in the waveguide mode of the photonic crystal optical waveguide is matched with that of the incident light, and furthermore, in addition to the method above, the distribution of light intensity on the incident end surface in the waveguide mode of the photonic crystal optical waveguide is matched with that of the incident light. A photonic crystal optical waveguide and channel optical waveguide are joined together, and the structure of the channel optical waveguide is wedge shaped in the joint section.Type: GrantFiled: September 13, 2005Date of Patent: August 17, 2010Assignee: NEC CorporationInventors: Akiko Gomyo, Jun Ushida
-
Publication number: 20100119192Abstract: In a waveguide path coupling-type photodiode, a semiconductor light absorbing layer and an optical waveguide path core are adjacently arranged. An electrode formed of at least one layer is installed in a boundary part of the semiconductor light absorbing layer and the optical waveguide path core. The electrodes are arranged at an interval of (1/100)? to ? [?: wavelength of light transmitted through optical waveguide path core]. At least a part of the electrodes is embedded in the semiconductor light absorbing layer. Embedding depth from a surface of the semiconductor light absorbing layer is a value not more than ?/(2ns) [ns: refractive index of semiconductor light absorbing layer]. At least one layer of the electrode is constituted of a material which can surface plasmon-induced.Type: ApplicationFiled: April 30, 2008Publication date: May 13, 2010Applicants: NEC CORPORATION, NIPPON TELEGRAPH AND TELEPHONE CORPORATIONInventors: Junichi Fujikata, Jun Ushida, Daisuke Okamoto, Kenichi Nishi, Keishi Ohashi, Tai Tsuchizawa, Seiichi Itabashi
-
Patent number: 7715665Abstract: In an optical circuit including multi-dimensional photonic crystals, in which the optical circuit has a structure (33), such as a light emitting member or a light receiving member, having a natural resonance frequency, another structure (34) having a natural resonance frequency slightly differing from the natural resonance frequency of the structure (33) is arranged in the vicinity of the structure (33) to control the directivity of localization and propagation of an electromagnetic field, light emission and light reception in a spatial region including the above structures in the multi-dimensional photonic crystals, in order to permit functional operations to be realized.Type: GrantFiled: February 15, 2008Date of Patent: May 11, 2010Assignee: NEC CorporationInventors: Jun Ushida, Hirohito Yamada
-
Publication number: 20100092132Abstract: A waveguide connecting structure includes a light branching element (111) for branching light from an input optical waveguide (201) including one core into two branched light components having the same optical power and the same phase, and a twin-arm waveguide (113) including a pair of arm waveguides (113A, 113B) for outputting the light components branched by the light branching element to a slot waveguide (202) including two cores arranged in parallel at a narrow spacing. The pair of arm waveguides have cores formed in a cladding on a substrate and having a refractive index higher than that of the cladding, and are formed such that the spacing between them gradually narrows and becomes equal to the core spacing of the slot waveguide from the core input ends into which the branched light components enter toward the core output ends from which the light components are output to the slot waveguide.Type: ApplicationFiled: December 12, 2007Publication date: April 15, 2010Inventor: Jun Ushida
-
Publication number: 20090285522Abstract: There is provided an optical device and an optical waveguide composed of a photonic crystal in which two optical waveguide modes that are orthogonal to a light propagation direction can be used, whereby design latitude is increased. In the optical waveguide device composed of a photonic crystal, in a dispersion relationship of the photonic crystal, light is propagated using a refractive index guide mode that is a minimum frequency optical waveguide mode. Alternatively, two optical waveguide modes that are orthogonal to light propagation direction are used, a linear defect waveguide mode is used for the first optical waveguide mode; and light is propagated in the second light guide mode by using a refractive index guide mode that is a minimum frequency optical waveguide mode in a dispersion relationship of the photonic crystal.Type: ApplicationFiled: January 6, 2006Publication date: November 19, 2009Applicant: NEC CORPORATIONInventors: Akiko Gomiyou, Jun Ushida, Hirohito Yamada
-
Publication number: 20090142018Abstract: Disclosed in a method and a device in which a wave number of light in the waveguide mode of a photonic crystal optical waveguide is matched with that of the incident light, or a intensity ratio of electric field to magnetic field of the light in the waveguide mode of the photonic crystal optical waveguide is matched with that of the incident light, and furthermore, in addition to the method above, the distribution of light intensity on the incident end surface in the waveguide mode of the photonic crystal optical waveguide is matched with that of the incident light. A photonic crystal optical waveguide and channel optical waveguide are joined together, and the structure of the channel optical waveguide is wedge shaped in the joint section.Type: ApplicationFiled: January 26, 2009Publication date: June 4, 2009Inventors: Akiko Gomyo, Jun Ushida
-
Publication number: 20080316749Abstract: In an optical circuit including multi-dimensional photonic crystals, in which the optical circuit has a structure (33), such as a light emitting member or a light receiving member, having a natural resonance frequency, another structure (34) having a natural resonance frequency slightly differing from the natural resonance frequency of the structure (33) is arranged in the vicinity of the structure (33) to control the directivity of localization and propagation of an electromagnetic field, light emission and light reception in a spatial region including the above structures in the multi-dimensional photonic crystals, in order to permit functional operations to be realized.Type: ApplicationFiled: February 15, 2008Publication date: December 25, 2008Applicant: NEC CORPORATIONInventors: Jun USHIDA, Hirohito YAMADA