Patents by Inventor Takeo Kageyama
Takeo Kageyama 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: 7801198Abstract: A surface emitting laser element includes an active layer and a dielectric multilayer mirror formed with a plurality of dielectric layers having different refractive indices for reflecting a light generated in the active layer. At least one of boundaries between the dielectric layers is formed to have a predetermined surface roughness to obtain a desired target reflectance of the dielectric multilayer mirror.Type: GrantFiled: March 28, 2008Date of Patent: September 21, 2010Assignee: The Furukawa Electric Co., Ltd.Inventors: Takeo Kageyama, Norihiro Iwai, Yasumasa Kawakita, Keishi Takaki, Peter Nyakas
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Patent number: 7778297Abstract: A convex-portion forming layer is formed between a current-confinement aperture and a multilayer mirror, and forms a convex portion on each boundary between layers forming the multilayer mirror. The convex portion includes a plane equal to or larger than a spot size of the laser light, where the spot size is decided by a diameter of the current-confinement aperture, a predetermined diffraction angle of the laser light due to the current-confinement aperture, and a distance from the current-confinement aperture.Type: GrantFiled: March 27, 2008Date of Patent: August 17, 2010Assignee: The Furukawa Electric Co., Ltd.Inventors: Takeo Kageyama, Norihiro Iwai, Yasumasa Kawakita
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Publication number: 20100195689Abstract: A surface emitting laser element array comprises a plurality of surface emitting laser elements (15) on a same substrate (1) each comprising a mesa post formed of a laminated structure including an active layer (4) for reducing a crosstalk between the surface emitting laser elements constituting the surface emitting laser element array, and for improving a high speed response, wherein each of the surface emitting laser elements (15) comprises a first electrode (9), a second electrode (10) and a third electrode (11) that have a polarity different from that of the first electrode (9); the first electrode (9) is arranged on the mesa post; the second electrode (10) is arranged on one surface of the substrate (1) same as that of the first electrode (9); the third electrode (11) is arranged on the other surface of the substrate (1) opposite to that of the first electrode and the second electrode (9, 10) and is provided as a common electrode of the surface emitting laser elements (15); and an electric current is appType: ApplicationFiled: September 1, 2006Publication date: August 5, 2010Applicant: The Furukawa Electric Co., Ltd.Inventors: Maiko Ariga, Takeo Kageyama, Norihiro Iwai, Kazuaki Nishikata
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Publication number: 20100008674Abstract: To provide a surface emitting laser device including a substrate; an optical resonator arranged on the substrate, the optical resonator including a lower multilayer reflector and an upper multilayer reflector; a strained active layer arranged in the resonator, the strained active layer having a multiple quantum well structure formed with a quantum well layer and a barrier layer; and a current confinement layer arranged on an upper side of the strained active layer, the current confinement layer including a selectively oxidized portion, where the current confinement layer is arranged at a position where a strain in the selectively oxidized portion influences the strained active layer.Type: ApplicationFiled: July 10, 2009Publication date: January 14, 2010Applicant: FURUKAWA ELECTRIC CO., LTD.Inventors: Hitoshi Shimizu, Takeo Kageyama
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Publication number: 20090310637Abstract: A convex-portion forming layer is formed between a current-confinement aperture and a multilayer mirror, and forms a convex portion on each boundary between layers forming the multilayer mirror. The convex portion includes a plane equal to or larger than a spot size of the laser light, where the spot size is decided by a diameter of the current-confinement aperture, a predetermined diffraction angle of the laser light due to the current-confinement aperture, and a distance from the current-confinement aperture.Type: ApplicationFiled: March 27, 2008Publication date: December 17, 2009Applicant: The Furukawa Electric Co, Ltd.Inventors: Takeo Kageyama, Norihiro Iwai, Yasumasa Kawakita
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Publication number: 20090268773Abstract: A surface emitting laser element that includes a cylindrical mesa post in which a plurality of semiconductor layers including an active layer is grown and that emits a laser light in a direction perpendicular to a substrate surface, the surface emitting laser element including a dielectric multilayer film on a top surface of the mesa post in at least a portion over a current injection area of the active layer; and a dielectric portion that includes layers fewer than layers of the dielectric multilayer film and that is arranged on a portion excluding the portion over the current injection area on the top surface of the mesa post and on at least part of a side surface of the mesa post.Type: ApplicationFiled: April 24, 2008Publication date: October 29, 2009Applicant: THE FURUKAWA ELECTRIC CO.,LTD.,Inventors: Norihiro IWAI, Takeo Kageyama, Kinuka Tanabe
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Publication number: 20090245312Abstract: Provided is a surface emitting laser element array of low cost and high reliability. The surface emitting laser element array has a substrate having a semiconductor of a first conduction type; and a plurality of surface emitting laser elements each having, above the substrate, an active layer sandwiched between a first conduction type semiconductor layer area and a second conduction type semiconductor layer area and disposed between a upper reflective mirror and a lower reflective mirror, the surface emitting laser elements being separated from each other by an electric separation structure formed having such a depth as to reach the substrate. The first conduction type semiconductor layer area is arranged between the substrate and the active layer.Type: ApplicationFiled: March 30, 2009Publication date: October 1, 2009Applicant: THE FURUKAWA ELECTRIC CO., LTDInventors: Takeo Kageyama, Keishi Takaki, Naoki Tsukiji, Norihiro Iwai, Hitoshzi Shimizu, Yasumasa Kawakita, Suguru Imai
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Patent number: 7577176Abstract: An optical resonator including a lower multilayer reflector and an upper multilayer reflector is arranged on a substrate. A strained active layer having a multiple quantum well structure formed with a quantum well layer and a barrier layer is arranged in the resonator. A current confinement layer including a selectively oxidized portion is arranged on an upper side of the strained active layer. The current confinement layer is arranged at a position where a strain in the selectively oxidized portion influences the strained active layer.Type: GrantFiled: February 29, 2008Date of Patent: August 18, 2009Assignee: The Furukawa Electric Co., Ltd.Inventors: Hitoshi Shimizu, Takeo Kageyama
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Publication number: 20080273569Abstract: A VCSEL device includes a polyimide having a larger thickness (d1) on the surface of a semiconductor layer structure in a peripheral area 54, which is separated from a mesapost by an annular groove 52. The top surface of the central mesapost 30 is located at a lower position compared to the top surface of the peripheral area 54. A structure is obtained wherein the mesapost is not contacted by a jig or probe during handling the device in the test or assembly thereof.Type: ApplicationFiled: July 2, 2008Publication date: November 6, 2008Applicant: The Furukawa Electric Co, Ltd.Inventors: Koji HIRAIWA, Takeo Kageyama, Norihiro Iwai, Keishi Takaki
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Publication number: 20080240192Abstract: A surface emitting laser element includes an active layer and a dielectric multilayer mirror formed with a plurality of dielectric layers having different refractive indices for reflecting a light generated in the active layer. At least one of boundaries between the dielectric layers is formed to have a predetermined surface roughness to obtain a desired target reflectance of the dielectric multilayer mirror.Type: ApplicationFiled: March 28, 2008Publication date: October 2, 2008Applicant: The Furukawa Electric Co, Ltd.Inventors: Takeo KAGEYAMA, Norihiro Iwai, Yasumasa Kawakita, Keishi Takaki, Peter Nyakas
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Publication number: 20080212633Abstract: An optical resonator including a lower multilayer reflector and an upper multilayer reflector is arranged on a substrate. A strained active layer having a multiple quantum well structure formed with a quantum well layer and a barrier layer is arranged in the resonator. A current confinement layer including a selectively oxidized portion is arranged on an upper side of the strained active layer. The current confinement layer is arranged at a position where a strain in the selectively oxidized portion influences the strained active layer.Type: ApplicationFiled: February 29, 2008Publication date: September 4, 2008Applicant: THE FURUKAWA ELECTRIC CO., LTD.Inventors: Hitoshi Shimizu, Takeo Kageyama
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Publication number: 20080205463Abstract: A selective oxidation layer is formed by alternately growing an AlAs layer and an XAs layer containing a group III element X with a thickness ratio in a range between 97:3 and 99:1 on a plurality of semiconductor layers including an active layer. The selective oxidation layer is selectively oxidized to manufacture a vertical-cavity surface-emitting laser.Type: ApplicationFiled: February 11, 2008Publication date: August 28, 2008Applicant: The Furukawa Electric Co., Ltd.Inventors: Keishi TAKAKI, Norihiro Iwai, Hitoshi Shimizu, Takeo Kageyama
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Patent number: 7418020Abstract: A VCSEL device includes a polyimide having a larger thickness (d1) on the surface of a semiconductor layer structure in a peripheral area 54, which is separated from a mesapost by an annular groove 52. The top surface of the central mesapost 30 is located at a lower position compared to the top surface of the peripheral area 54. A structure is obtained wherein the mesapost is not contacted by a jig or probe during handling the device in the test or assembly thereof.Type: GrantFiled: October 31, 2006Date of Patent: August 26, 2008Assignee: The Furukawa Electric Co., Ltd.Inventors: Koji Hiraiwa, Takeo Kageyama, Norihiro Iwai, Keishi Takaki
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Publication number: 20070153856Abstract: An active layer is formed by arranging a plurality of quantum-well layers and a plurality of barrier layers alternatively. An amount of band discontinuity in a conduction band between a barrier layer that is sandwiched by the quantum-well layers and adjacent quantum-well layers is equal to or more than 26 meV and less than 300 meV, so that an overflow of injected carriers due to a thermal excitation between the quantum-well layers is intentionally caused to make the carrier density uniform between the quantum-well layers.Type: ApplicationFiled: December 15, 2006Publication date: July 5, 2007Applicant: THE FURUKAWA ELECTRIC CO., LTD.Inventors: Takeo KAGEYAMA, Yoshihiko Ikenaga
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Publication number: 20070110115Abstract: A VCSEL device includes a polyimide having a larger thickness (d1) on the surface of a semiconductor layer structure in a peripheral area 54, which is separated from a mesapost by an annular groove 52. The top surface of the central mesapost 30 is located at a lower position compared to the top surface of the peripheral area 54. A structure is obtained wherein the mesapost is not contacted by a jig or probe during handling the device in the test or assembly thereof.Type: ApplicationFiled: October 31, 2006Publication date: May 17, 2007Applicant: The Furukawa Electric Co, Ltd.Inventors: Koji HIRAIWA, Takeo Kageyama, Norihiro Iwai, Keishi Takaki
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Publication number: 20070091965Abstract: A vertical-cavity surface-emitting (VCSEL) device has a layer structure including a top DBR mirror, an active layer, a current confinement oxide layer, and a bottom DBR mirror, the layer structure being configured as a mesa post. The current confinement oxide layer has a central current injection area and a peripheral current blocking area oxidized from the sidewall of the mesa post. The mesa post has a substantially square cross-sectional shape, thereby allowing an oxidation heat treatment to configure a substantially circular current injection area in the current-confinement oxide layer.Type: ApplicationFiled: October 19, 2006Publication date: April 26, 2007Applicant: FURUKAWA ELECTRIC CO., LTD.Inventors: Kinuka Tanabe, Yoshihiko Ikenaga, Norihiro Iwai, Takeo Kageyama, Koji Hiraiwa, Hirokazu Yoshikawa
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Publication number: 20070030874Abstract: A cavity is formed by a lower multilayer mirror and an upper multilayer mirror and an active layer is arranged between the lower multilayer mirror and the upper multilayer mirror in a surface-emitting laser element. A relaxation oscillation frequency at a bias point in the cavity is set to exceed an optical communication frequency for modulating a laser light output from the surface-emitting laser element.Type: ApplicationFiled: September 5, 2006Publication date: February 8, 2007Applicant: The Furukawa Electric Co, Ltd.Inventors: Maiko Ariga, Norihiro Iwai, Setiagung Casimirus, Hitoshi Shimizu, Fumio Koyama, Masakazu Arai, Takeo Kageyama
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Publication number: 20060193361Abstract: A vertical cavity surface emitting laser (VCSEL) device includes has an epitaxial layer structure formed on a GaAs substrate and including a pair of multilayer reflectors and a tunnel junction structure. The tunnel junction structure is configured by a heavily-doped n-type Tix2Inx1Ga1-x1-x2As1-y1-y2Ny1Sby2 mixed-crystal layer and a heavily-doped p-type Tix4Inx3Ga1-x3-x4As1-y3-y4Ny3Sby4 mixed-crystal layer, where 0?x2?0.3, 0?x1?0.3, 0<y1?0.05, 0<y2?0.3, 0?x4?0.3, 0?x3?0.05, 0<y3?0.05, and 0<y4?0.3.Type: ApplicationFiled: February 6, 2006Publication date: August 31, 2006Applicant: THE FURUKAWA ELECTRIC CO., LTD.Inventors: Setiagung Casimirus, Takeo Kageyama