Patents by Inventor Hisato Uetsuka
Hisato Uetsuka 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: 6980707Abstract: A waveguide type variable optical attenuator has: a substrate; two optical circuits that are in parallel formed on the substrate, each of the optical circuits including two couplers that conduct the branching and coupling of light and are connected to the input port and output port of light and two waveguides through which the two couplers are connected; a polarization maintaining fiber one end of which is connected to the output port of one of the two optical circuits and the other end of which is connected to the input port of the other of the two optical circuits while being twisted 90°; and a heater that is provided around neighboring waveguides of the two optical circuits such that the neighboring waveguides share heat to be generated by the heater.Type: GrantFiled: September 4, 2003Date of Patent: December 27, 2005Assignee: Hitachi Cable, Ltd.Inventors: Takafumi Chiba, Satoshi Takasugi, Tetsu Hasegawa, Hisato Uetsuka
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Patent number: 6947631Abstract: A waveguide-type optical multiplexer/demultiplexer with low crosstalk characteristics and reduced wavelength dispersion is provided. A waveguide-type optical multiplexer/demultiplexer comprising, first, second and third optical multiplexer/demultiplexer circuits connected in multistage, each multiplexer/demultiplexer circuit has four input-output ports, third input-output port of first optical multiplexer/demultiplexer circuit is connected to third input-output port of second optical multiplexer/demultiplexer circuit, and fourth input-output port of first optical multiplexer/demultiplexer circuit is connected to fourth input-output port of third optical multiplexer/demultiplexer circuit, when wavelength division multiplex signals having wavelength ?1, ?2, ?3, ?4, ?5, ?6 . . . are input through first input-output port of first optical multiplexer/demultiplexer circuit, multiplex signals of odd wavelength ?1, ?3, ?5 . . .Type: GrantFiled: November 8, 2002Date of Patent: September 20, 2005Assignee: Hitachi Cable, Ltd.Inventors: Hideaki Arai, Takafumi Chiba, Hisato Uetsuka, Masahiro Hikage
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Patent number: 6724954Abstract: In an optical multiplexer/demultiplexer comprising optical multiplexer/demultiplexer circuits connected in multistage, the optical multiplexer/demultiplexer circuits each have two input ports and two output ports, an optical path, through which input optical signals with predetermined wavelengths are output after multiplexing and demultiplexing, varies depending upon the input port; the optical paths in each of the optical multiplexer/demultiplexer circuits have mutually opposite wavelength dispersion characteristics, and one of the optical paths in a first optical multiplexer/demultiplexer circuit is connected to one of the optical paths, in a second optical multiplexer/demultiplexer circuit, having wavelength dispersion characteristics opposite to the optical path in the first optical multiplexer/demultiplexer circuit.Type: GrantFiled: March 2, 2001Date of Patent: April 20, 2004Assignee: Hitachi Cable, Inc.Inventors: Hideaki Arai, Takafumi Chiba, Hisato Uetsuka
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Publication number: 20040047583Abstract: A waveguide type variable optical attenuator has: a substrate; two optical circuits that are in parallel formed on the substrate, each of the optical circuits including two couplers that conduct the branching and coupling of light and are connected to the input port and output port of light and two waveguides through which the two couplers are connected; a polarization maintaining fiber one end of which is connected to the output port of one of the two optical circuits and the other end of which is connected to the input port of the other of the two optical circuits while being twisted 90°; and a heater that is provided around neighboring waveguides of the two optical circuits such that the neighboring waveguides share heat to be generated by the heater.Type: ApplicationFiled: September 4, 2003Publication date: March 11, 2004Applicant: Hitachi Cable, Ltd.Inventors: Takafumi Chiba, Satoshi Takasugi, Tetsu Hasegawa, Hisato Uetsuka
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Patent number: 6668107Abstract: An optical switching apparatus and a method of efficiently switching optical signals are disclosed. Optical insertion loss may be reduced in a planar lightwave circuit by determining an optimal spacing between perturbations including using passive perturbations, having a three dimensional refractive index distribution, in an array of waveguides, or by adjusting parameters of existing perturbations e.g. their spacing. The perturbation and each waveguide have different three dimensional refractive index distributions. The perturbation may be positioned anywhere in the array of waveguides. The perturbation may be a trench, a region of refractive index different from that in each waveguide, a broken waveguide core, or a modification of the topography of the array of waveguides. In one embodiment, the perturbation is a periodic or quasiperiodic perturbation.Type: GrantFiled: December 21, 2001Date of Patent: December 23, 2003Assignees: Agilent Technologies, Inc., Hitachi Cable, Ltd. of JapanInventors: Marshall Thomas DePue, Shalini Venkatesh, Hisato Uetsuka, Hiroaki Okano
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Patent number: 6631223Abstract: In the optical multiplexer/demultiplexer according to the invention, an MMI (multi mode interference) coupler having a percentage coupling of about 50% is used as first and second optical couplers, and a directional coupler having a percentage coupling of less than 10% is used as third and fourth optical couplers. By virtue of this constitution, the optical multiplexer/demultiplexer according to the invention has a small dependency upon wavelength and can be used in a wide waveband, is less susceptible to a preparation error, and, at the same time, has good wavelength flatness in passband and a wide rejection band.Type: GrantFiled: February 15, 2001Date of Patent: October 7, 2003Assignee: Hitachi Cable, Ltd.Inventors: Hideaki Arai, Takafumi Chiba, Hisato Uetsuka
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Publication number: 20030123778Abstract: An optical switching apparatus and a method of efficiently switching optical signals are disclosed. Optical insertion loss may be reduced in a planar lightwave circuit by determining an optimal spacing between perturbations including using passive perturbations, having a three dimensional refractive index distribution, in an array of waveguides, or by adjusting parameters of existing perturbations e.g. their spacing. The perturbation and each waveguide have different three dimensional refractive index distributions. The perturbation may be positioned anywhere in the array of waveguides. The perturbation may be a trench, a region of refractive index different from that in each waveguide, a broken waveguide core, or a modification of the topography of the array of waveguides. In one embodiment, the perturbation is a periodic or quasiperiodic perturbation.Type: ApplicationFiled: December 21, 2001Publication date: July 3, 2003Inventors: Marshall Thomas DePue, Shalini Venkatesh, Hisato Uetsuka, Hiroaki Okano
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Publication number: 20030091071Abstract: A waveguide-type optical multiplexer/demultiplexer with low crosstalk characteristics and reduced wavelength dispersion is provided. A waveguide-type optical multiplexer/demultiplexer comprising, first, second and third optical multiplexer/demultiplexer circuits connected in multistage, each multiplexer/demultiplexer circuit has four input-outpu ports, third input-output port of first optical multiplexer/demultiplexer circuit is connected to third input-output port of second optical multiplexer/demultiplexer circuit, and fourth input-output port of first optical multiplexer/demultiplexer circuit is connected to fourth input-output port of third optical multiplexer/demultiplexer circuit, when wavelength division multiplex signals having wavelength &lgr;1, &lgr;2, &lgr;3, &lgr;4, &lgr;5, &lgr;6 . . . are input through first input-output port of first optical multiplexer/demultiplexer circuit, multiplex signals of odd wavelength &lgr;1, &lgr;3, &lgr;5 . . .Type: ApplicationFiled: November 8, 2002Publication date: May 15, 2003Inventors: Hideaki Arai, Takafumi Chiba, Hisato Uetsuka, Masahiro Hikage
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Patent number: 6556749Abstract: The present invention relates to an array waveguide grating and a method of manufacture thereof, in which a substantially smooth wavelength-loss characteristics is obtained in a pass band, rather than increasing the loss. In an array waveguide grating (10), wavelength multiplex division signal light is demultiplexed by a channel waveguide array (15), reflected by a Fabry-Perot resonator array (16), and passed through the channel waveguide array (15) again, so that a substantially smooth wavelength-loss characteristic is obtained in the pass band, rather than increasing the loss.Type: GrantFiled: August 2, 2001Date of Patent: April 29, 2003Assignee: Hitachi Cable LimitedInventors: Hisato Uetsuka, Masahiro Okawa, Koichi Maru, Takafumi Chiba
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Patent number: 6549696Abstract: An optical wavelength multiplexer/demultiplexer includes a substrate, an input channel waveguide, an input slab waveguide, a channel waveguide array which has a plurality of channel waveguides, each channel waveguide differing in length from its neighboring waveguide by predetermined amount, an output slab waveguide, and a plurality of output channel waveguides. The input slab waveguide or output slab waveguide have a temperature compensation material, in its light path, having an opposite sign of diffraction temperature change to the plurality of channel wave guides, or a material capable of canceling a change in the in-phase plane of light having each wavelength which occurs in a vicinity of the channel waveguide array and the slab waveguide, or a waveguide for band width adjustment on which a waveguide to adjust band width of wavelength multiplexing light is provided.Type: GrantFiled: August 8, 2000Date of Patent: April 15, 2003Assignee: Hitachi Cable, Ltd.Inventors: Hisato Uetsuka, Masahiro Okawa, Koichi Maru, Hideki Nounen, Tatsuo Teraoka
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Publication number: 20030007728Abstract: The present invention relates to an array waveguide grating and a method of manufacture thereof, in which a substantially smooth wavelength-loss characteristics is obtained in a pass band, rather than increasing the loss. In an array waveguide grating (10), wavelength multiplex division signal light is demultiplexed by a channel waveguide array (15), reflected by a Fabry-Perot resonator array (16), and passed through the channel waveguide array (15) again, so that a substantially smooth wavelength-loss characteristic is obtained in the pass band, rather than increasing the loss.Type: ApplicationFiled: August 2, 2001Publication date: January 9, 2003Inventors: Hisato Uetsuka, Masahiro Okawa, Koichi Maru, Takafumi Chiba
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Publication number: 20010051018Abstract: In the optical multiplexer/demultiplexer according to the invention, an MMI (multi mode interference) coupler having a percentage coupling of about 50% is used as first and second optical couplers, and a directional coupler having a percentage coupling of less than 10% is used as third and fourth optical couplers. By virtue of this constitution, the optical multiplexer/demultiplexer according to the invention has a small dependency upon wavelength and can be used in a wide waveband, is less susceptible to a preparation error, and, at the same time, has good wavelength flatness in passband and a wide rejection band.Type: ApplicationFiled: February 15, 2001Publication date: December 13, 2001Inventors: Hideaki Arai, Takafumi Chiba, Hisato Uetsuka
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Publication number: 20010048786Abstract: In an optical multiplexer/demultiplexer comprising optical multiplexer/demultiplexer circuits connected in multistage, the optical multiplexer/demultiplexer circuits each have two input ports and two output ports, an optical path, through which input optical signals with predetermined wavelengths are output after multiplexing and demultiplexing, varies depending upon the input port; the optical paths in each of the optical multiplexer/demultiplexer circuits have mutually opposite wavelength dispersion characteristics, and one of the optical paths in a first optical multiplexer/demultiplexer circuit is connected to one of the optical paths, in a second optical multiplexer/demultiplexer circuit, having wavelength dispersion characteristics opposite to the optical path in the first optical multiplexer/demultiplexer circuit.Type: ApplicationFiled: March 2, 2001Publication date: December 6, 2001Inventors: Hideaki Arai, Takafumi Chiba, Hisato Uetsuka
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Patent number: 6317534Abstract: An optical wavelength routing device comprises an arrayed waveguide comprising a plurality of channel waveguides formed on a substrate, a plurality of input waveguides having 12 input ports located on an input side of the arrayed waveguide, a plurality of output waveguides having 16 input ports located on an output side of the arrayed waveguide, an input slab waveguide for coupling the plurality of input waveguides to the arrayed waveguide to provide a first coupling portion on the side of the input waveguide, and an output slab waveguide for coupling the arrayed waveguide to the plurality of output waveguides to provide a second coupling portion on the side of the output waveguide, in which central wavelengths of lights input to the input ports and output from the output ports are controlled such that a difference between a predetermined wavelength and a central wavelength is suppressed within the range of +&dgr;&lgr;/4.Type: GrantFiled: December 18, 1998Date of Patent: November 13, 2001Assignees: Kokusai Denshin Denwa Co., Ltd., Hitachi Cable Ltd.Inventors: Tetsuya Miyazaki, Shu Yamamoto, Koichi Maru, Hisato Uetsuka
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Patent number: 6093334Abstract: A glass wave guide element, which is small in size and amenable to integration and mass-production, and a method of manufacturing the glass wave guide element are provided. The glass wave guide element includes a core having a diffraction grating formed on an under cladding, an over cladding covering the core and a heater for changing the Bragg wavelength of the diffraction grating, the heater being arranged on the over cladding. The core and a central portion of both claddings in a surrounding portion around the core are formed in a state of being continuously separated along a longitudinal direction of the core from the substrate through a gap, and the core and the surrounding portion around the core are formed in a state of being spatially intermittently separated in a width direction of the core from a surrounding portion of both claddings through a gap.Type: GrantFiled: November 17, 1999Date of Patent: July 25, 2000Assignee: Hitachi Cable, Ltd.Inventors: Ryoji Suzuki, Hisato Uetsuka, Dai Kobayashi, Hideaki Arai, Korenori Tamura
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Patent number: 6069990Abstract: An optical wavelength multiplexer/demultiplexer, comprising: a substrate: and, provided thereon, input waveguides, output waveguides, an array waveguide diffraction grating comprising a plurality of waveguides with a predetermined difference in length being provided between the waveguides, an input slab waveguide for connecting the input waveguides to the array waveguide diffraction grating, an output slab waveguide for connecting the output waveguides to the array waveguide diffraction grating, and multimode waveguides, for example, tapered waveguides and parabolic waveguides, provided in a connecting section between the input waveguides and the input slab waveguide. The output slab waveguide may have a smaller radius than the input slab waveguide to narrow the width of the electric field distribution on the output side. The above construction can bring wavelength characteristics to a rectangular form to broaden the transmission band and at the same time can reduce the loss.Type: GrantFiled: June 3, 1998Date of Patent: May 30, 2000Assignee: Hitachi Cable Ltd.Inventors: Masahiro Okawa, Hisato Uetsuka, Hideaki Arai, Koichi Maru
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Patent number: 6031957Abstract: A glass wave guide element, which is small in size and amenable to integration and mass-production, and a method of manufacturing the glass wave guide element are provided. The glass wave guide element includes a core 3 having a diffraction grating formed on an under cladding 2, an over cladding 4 covering the core 3 and a heater 6 for changing the Bragg wavelength of the diffraction grating, the heater being arranged on the over cladding 4. The core 3 and a central portion (2B, 4B) of both claddings in a surrounding portion around the core 3 are formed in a state of being continuously separated along a longitudinal direction of the core 3 from the substrate 1 through a gap 5, and the core 3 and the surrounding portion around the core 3 are formed in a state of being spatially intermittently separated in a width direction of the core 3 from a surrounding portion (2A, 2C, 4A, 4C) of both claddings through a gap.Type: GrantFiled: May 21, 1998Date of Patent: February 29, 2000Assignee: Hitachi Cable Ltd.Inventors: Ryoji Suzuki, Hisato Uetsuka, Dai Kobayashi, Hideaki Arai, Korenori Tamura
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Patent number: 6021239Abstract: A photocoupler according to the present invention includes: an optical waveguide including a substrate, at least a first dielectric layer provided on the substrate, the first dielectric layer having a tapered structure whose thickness varies in an x-direction in which light is propagated after coupling, and a second dielectric layer provided on the first dielectric layer; a light incidence component provided above the optical waveguide, which causes light incident thereon to be directed toward a surface of the optical waveguide at a prescribed angle; and a bonding section for bonding the light incidence component to the optical waveguide. The bonding section has an edge surface which makes contact with the surface of the waveguide in a straight line and has a portion which makes contact with neither the light incidence component nor the surface of the optical waveguide. The tapered structure of the first dielectric layer has a shape set such that a radiation pattern of light with a wavelength .lambda.Type: GrantFiled: October 29, 1997Date of Patent: February 1, 2000Assignees: Sharp Kabushiki Kaisha, Hitachi Cable, Ltd.Inventors: Kohji Minami, Yukio Kurata, Hisato Uetsuka, Hirobumi Ouchi
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Patent number: 5995691Abstract: A waveguide type grating device according to the invention includes a quartz substrate, a cladding and two waveguides. Waveguides are arranged to provide an input port, an Add port, an output port, a Drop port, directional 3 dB couplers, core width-changing portions, and grating portions each interposed between core width-changing portions. The width of core is changed between each non-grating portion and each grating portion in an adiabatic structure, for example, a parabolic structure. For this structure, a waveguide type grating device is structured to suppress the increase in wavelength loss due to coupling from progressive propagation mode to regressive radiation mode, with less cost and smaller dimension.Type: GrantFiled: May 1, 1998Date of Patent: November 30, 1999Assignee: Hitachi Cable, Ltd.Inventors: Hideaki Arai, Ryoji Suzuki, Korenori Tamura, Hisato Uetsuka
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Patent number: 5903697Abstract: An optical waveguide 3 comprises a substrate like a Si substrate having a projection with a flat surface and inclined side surfaces thereon, a buffer layer having a refractive index of n.sub.0 formed on lower surfaces of the substrate, a secondary buffer layer having a refractive index of n.sub.0 formed on the buffer layer, a core waveguide having a refractive index of n.sub.1 formed on the secondary buffer layer and a cladding layer having a refractive index of n.sub.0 covering the core waveguide. The flat surface of the projection 31 is exposed through an opening. The secondary buffer layer controls a transmission loss increase caused by partial thickness differences of the ground buffer layer or scattering by scratches or strains created by the grind.Type: GrantFiled: July 22, 1997Date of Patent: May 11, 1999Assignees: Hitachi Ltd., Hitachi Cable, Ltd., Nippon Telegraph and Telephone CorporationInventors: Yasufumi Yamada, Masahiro Yanagisawa, Hiroaki Okano, Keiichi Higuchi, Hisato Uetsuka, Tatsuo Teraoka, Satoshi Aoki, Yasunori Iwafuji