Patents by Inventor Hirofumi Aota

Hirofumi Aota 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: 20140078508
    Abstract: An optical module includes an interferometer having at least two optical exit ends; an optoelectronic converting element having at least two light-receiving surfaces; and plural lenses that are disposed between the interferometer and the optoelectronic converting element, that optically couple light exiting from the interferometer with two light-receiving surfaces of the optoelectronic converting element. The lenses are disposed having focal distances and a distance therebetween that reduce positional displacement on the two light-receiving surfaces of the optoelectronic converting element, the positional displacement being generated at each of the two optical exit ends of the interferometer.
    Type: Application
    Filed: November 20, 2013
    Publication date: March 20, 2014
    Applicant: Fujitsu Optical Components Limited
    Inventor: Hirofumi AOTA
  • Patent number: 8285088
    Abstract: A wavelength selective switch for suppressing degradation of pass band characteristics when the temperature rises. The wavelength selective switch includes a spectroscopic element for separating input light and providing angular dispersion depending on wavelengths, a collective lens for gathering light output from the spectroscopic element, and a movable reflection block which includes a plurality of mirrors arranged in the direction of angular dispersion made by the spectroscopic element, changes the angles of the mirrors in a direction differing from the direction of angular dispersion, and reflects the light coming from the collective lens. The collective lens is fixed at one end with respect to the direction of angular dispersion, expands with heat in a direction in which it is not fixed when the temperature rises, and outputs the light in a direction opposite to the direction in which the angle of light output from the spectroscopic element changes.
    Type: Grant
    Filed: February 5, 2008
    Date of Patent: October 9, 2012
    Assignee: Fujitsu Limited
    Inventors: Hirofumi Aota, Kohei Shibata, Tsuyoshi Yamamoto
  • Patent number: 8243372
    Abstract: An optical apparatus includes a collimation optical member for collimating and outputting input light, a condensing optical member for condensing light from the collimation optical member and a light blocking mask member provided at a place on an optical path of the input light for light blocking part of the input light, and enhances the degree of freedom in design of an optical system.
    Type: Grant
    Filed: January 21, 2009
    Date of Patent: August 14, 2012
    Assignee: Fujitsu Limited
    Inventors: Hirofumi Aota, Kohei Shibata, Tamotsu Akashi, Tsuyoshi Yamamoto
  • Patent number: 8165470
    Abstract: In a wavelength selecting switch, light output from an input port of an input/output optical system is angularly dispersed according to a wavelength thereof, with a spectral element. Then the lights of respective wavelengths are collected by a light collecting optical system and reflected with a corresponding reflecting mirror of a mirror section. The reflected light corresponding to the angle of the reflecting mirror, is input to an output port at an output destination of the input/output optical system. The respective output ports of the input/output optical system each have a lens coupled to an end face of an optical fiber, and the lens has a structure where a focal length of a first region corresponding to inside a variable range of attenuation is different from a focal length of a second region corresponding to outside the variable range.
    Type: Grant
    Filed: April 30, 2009
    Date of Patent: April 24, 2012
    Assignee: Fujitsu Limited
    Inventors: Hirofumi Aota, Tamotsu Akashi, Tsuyoshi Yamamoto
  • Patent number: 7982957
    Abstract: In an optical apparatus according to the present invention, the lens thicknesses and curvature radiuses of respective first lenses are optimized so that beam waist positions of optical beams emitted from the respective first lenses of a lens array are independently changed according to aberration of a second lens, and the focal position deviation due to the aberration of the second lens is cancelled by a difference between the beam waist positions, which is given on the lens array side. As a result, it is possible to suppress, at a low cost, variations in focal positions of the optical beams which are emitted from respective ports of the lens array to be condensed by the common lens.
    Type: Grant
    Filed: July 11, 2007
    Date of Patent: July 19, 2011
    Assignee: Fujitsu Limited
    Inventors: Shinichi Takeuchi, Tamotsu Akashi, Hirofumi Aota
  • Patent number: 7787721
    Abstract: The MEMS mirror, which has a reflective surface whose angle is variably changed, is provided with a portion whose reflectance is lowered than that of a center portion. The portion is provided in at least part of ends on a predetermined side of the MEMS mirror. As a result, a diffraction influence of light reflected by the end surfaces can be reduced at the time of angle change of the MEMS mirror.
    Type: Grant
    Filed: January 28, 2005
    Date of Patent: August 31, 2010
    Assignee: Fujitsu Limited
    Inventors: Hirofumi Aota, Tamotsu Akashi
  • Patent number: 7706049
    Abstract: The present mirror device for suppressing PDL on the assumption of multiple modes of angles of input light and output light to movable mirrors with respect to the crystal axis of a crystal member at the time light passes through the crystal member. The mirror device includes a mirror system 2 and a flat-shaped crystal member 3 which is arranged in such a manner that a first angle is not larger than a second angle. The crystal member is constructed in such a manner that a third angle is substantially equal to a half of a fourth angle.
    Type: Grant
    Filed: February 20, 2008
    Date of Patent: April 27, 2010
    Assignee: Fujitsu Limited
    Inventors: Hirofumi Aota, Kohei Shibata, Tamotsu Akashi, Tsuyoshi Yamamoto
  • Publication number: 20100021167
    Abstract: In a wavelength selecting switch, light output from an input port of an input/output optical system is angularly dispersed according to a wavelength thereof, with a spectral element. Then the lights of respective wavelengths are collected by a light collecting optical system and reflected with a corresponding reflecting mirror of a mirror section. The reflected light corresponding to the angle of the reflecting mirror, is input to an output port at an output destination of the input/output optical system. The respective output ports of the input/output optical system each have a lens coupled to an end face of an optical fiber, and the lens has a structure where a focal length of a first region corresponding to inside a variable range of attenuation is different from a focal length of a second region corresponding to outside the variable range.
    Type: Application
    Filed: April 30, 2009
    Publication date: January 28, 2010
    Applicant: FUJITSU LIMITED
    Inventors: Hirofumi Aota, Tamotsu Akashi, Tsuyoshi Yamamoto
  • Patent number: 7653273
    Abstract: The optical switch includes: a spectroscopic device which separates wavelength division multiplexed (WDM) light into its component wavelengths; and a plurality of movable reflectors, arranged in a spectral direction at different intervals, for reflecting light of an individual component wavelength separated by said spectroscopic device. With this optical switch, deterioration of the characteristic of the pass band is avoided, so that the pass band characteristic is increased.
    Type: Grant
    Filed: January 24, 2005
    Date of Patent: January 26, 2010
    Assignee: Fujitsu Limited
    Inventors: Shinji Yamashita, Tsuyoshi Yamamoto, Tamotsu Akashi, Kohei Shibata, Hirofumi Aota, Osamu Tsuboi
  • Patent number: 7636503
    Abstract: A wavelength selective switch of the present invention angularly disperses lights output from a plurality of input ports of an input and output optical system, to an X-direction, according to wavelength, by a diffraction grating to supply the dispersed lights to a condenser lens. The condenser lens is arranged so that a center axis thereof is shifted to the X-direction relative to an axis passing through the center of spreading angle to the X-direction of output beams from the diffraction grating, and accordingly, at a non-operating time, the light of each wavelength passed through the condenser lens is incident on each movable mirror being tilted by an offset angle corresponding to a shift amount of the condenser lens. As a result, it becomes possible to block the connection between an input side and an output side at the non-operating time without degrading the performance at an operating time.
    Type: Grant
    Filed: March 11, 2008
    Date of Patent: December 22, 2009
    Assignee: Fujitsu Limited
    Inventors: Tsuyoshi Yamamoto, Tamotsu Akashi, Kohei Shibata, Hirofumi Aota, Shinji Yamashita
  • Publication number: 20090290223
    Abstract: An optical apparatus includes a collimation optical member for collimating and outputting input light, a condensing optical member for condensing light from the collimation optical member and a light blocking mask member provided at a place on an optical path of the input light for light blocking part of the input light, and enhances the degree of freedom in design of an optical system.
    Type: Application
    Filed: January 21, 2009
    Publication date: November 26, 2009
    Applicant: Fujitsu Limited
    Inventors: Hirofumi AOTA, Kohei Shibata, Tamotsu Akashi, Tsuyoshi Yamamoto
  • Patent number: 7613370
    Abstract: An optical switch includes an input port into which a multiplexed optical signal is input; a dispersing unit that, according to wavelength, disperses the multiplexed optical signal into a plurality of optical signals that are each dispersed in a unique direction; a converging unit that converges the dispersed optical signals; plural mirrors that are arrayed forming a single row in a plane and reflecting the converged optical signals, respectively; and plural output ports through which the reflected optical signals are output. Each of the mirrors has a concave reflective surface that is in the plane and of a predetermined curvature about an axis parallel to the plane.
    Type: Grant
    Filed: February 29, 2008
    Date of Patent: November 3, 2009
    Assignee: Fujitsu Limited
    Inventors: Kohei Shibata, Hirofumi Aota, Tamotsu Akashi, Toshiya Kishida, Hiroyuki Furukawa
  • Patent number: 7580599
    Abstract: An optical switch switches ports through which a beam is input and output and includes an optical system through which the beam passes; a movable reflector that is enclosed in a casing and reflects, at a variable angle, the beam that has passed through the optical system; and a transmissive window that is disposed in the casing at a position through which the beam passes, is made of a uniaxial crystal, and obtains a phase difference with respect to the beam passing therethrough having a wavelength ?. The phase difference is ?/4 times a positive odd integer and results from a setting of an orientation of a crystal axis and a thickness of the transmissive window.
    Type: Grant
    Filed: May 23, 2008
    Date of Patent: August 25, 2009
    Assignee: Fujitsu Limited
    Inventors: Hirofumi Aota, Kohei Shibata, Tamotsu Akashi, Tsuyoshi Yamamoto, Naoki Hashimoto
  • Publication number: 20090135488
    Abstract: An optical device and a wavelength selector switch are provided. The optical device includes a diffraction grating having first and second planes and first and second reflecting planes located on a first plane side of the diffraction grating. In the optical device, light input to the second plane of the diffraction grating is diffracted, and then an optical path of the diffracted light is re-input to the first plane of the diffraction grating newly via the first and the second reflecting planes.
    Type: Application
    Filed: November 7, 2008
    Publication date: May 28, 2009
    Applicant: Fujitsu Limited
    Inventors: Hirofumi AOTA, Kohei Shibata, Tamotsu Akashi, Tsuyoshi Yamamoto
  • Publication number: 20090060416
    Abstract: A wavelength selective switch of the present invention angularly disperses lights output from a plurality of input ports of an input and output optical system, to an X-direction, according to wavelength, by a diffraction grating to supply the dispersed lights to a condenser lens. The condenser lens is arranged so that a center axis thereof is shifted to the X-direction relative to an axis passing through the center of spreading angle to the X-direction of output beams from the diffraction grating, and accordingly, at a non-operating time, the light of each wavelength passed through the condenser lens is incident on each movable mirror being tilted by an offset angle corresponding to a shift amount of the condenser lens. As a result, it becomes possible to block the connection between an input side and an output side at the non-operating time without degrading the performance at an operating time.
    Type: Application
    Filed: March 11, 2008
    Publication date: March 5, 2009
    Applicant: Fujitsu Litmited
    Inventors: Tsuyoshi Yamamoto, Tamotsu Akashi, Kohei Shibata, Hirofumi Aota, Shinji Yamashita
  • Patent number: 7476038
    Abstract: An optical device module includes an optical device, a soaking unit fixed to one surface of the optical device, a heating/cooling unit fixed to one surface of the soaking unit, a heat-insulating unit fixed to one surface of the heating/cooling unit, and a package that houses the optical device, the soaking unit, the heating/cooling unit, and the heat-insulating unit and to which the heat-insulating unit is fixed. The heating/cooling unit heats the optical device using self-generated heat or cools the optical device via the soaking unit.
    Type: Grant
    Filed: March 22, 2004
    Date of Patent: January 13, 2009
    Assignee: Fujitsu Limited
    Inventors: Yoichi Oikawa, Hirofumi Aota, Kazuaki Akimoto, Hideyuki Miyata, Yumi Nakazawa, legal representative, Tadao Nakazawa
  • Publication number: 20080317405
    Abstract: An optical switch switches ports through which a beam is input and output and includes an optical system through which the beam passes; a movable reflector that is enclosed in a casing and reflects, at a variable angle, the beam that has passed through the optical system; and a transmissive window that is disposed in the casing at a position through which the beam passes, is made of a uniaxial crystal, and obtains a phase difference with respect to the beam passing therethrough having a wavelength ?. The phase difference is ?/4 times a positive odd integer and results from a setting of an orientation of a crystal axis and a thickness of the transmissive window.
    Type: Application
    Filed: May 23, 2008
    Publication date: December 25, 2008
    Applicant: FUJITSU LIMITED
    Inventors: Hirofumi Aota, Kohei Shibata, Tamotsu Akashi, Tsuyoshi Yamamoto, Naoki Hashimoto
  • Patent number: 7447399
    Abstract: In an optical switch comprising a wavelength spatially dispersive optical element for spatially dispersing a wavelength-multiplexed beam according to wavelengths, a plurality of output ports and a plurality of mirrors onto which beams dispersed by the element are irradiated, and each of which is able to direct a reflected beam to any one of the plural output ports, when an incident position of a reflected beam irradiated onto any one of the output ports is changed, the angle of the reflecting surface of a corresponding mirror among the plural mirrors is changed in a direction other than a direction in which the mirrors are arranged, whereby a protuberance in the vicinity of the out-band (side lobe) of the transmission band characteristic of the optical switch can be suppressed.
    Type: Grant
    Filed: March 18, 2005
    Date of Patent: November 4, 2008
    Assignee: Fujitsu Limited
    Inventors: Hirofumi Aota, Tamotsu Akashi
  • Publication number: 20080240650
    Abstract: An optical switch includes an input port into which a multiplexed optical signal is input; a dispersing unit that, according to wavelength, disperses the multiplexed optical signal into a plurality of optical signals that are each dispersed in a unique direction; a converging unit that converges the dispersed optical signals; plural mirrors that are arrayed forming a single row in a plane and reflecting the converged optical signals, respectively; and plural output ports through which the reflected optical signals are output. Each of the mirrors has a concave reflective surface that is in the plane and of a predetermined curvature about an axis parallel to the plane.
    Type: Application
    Filed: February 29, 2008
    Publication date: October 2, 2008
    Applicant: FUJITSU LIMITED
    Inventors: Kohei Shibata, Hirofumi Aota, Tamotsu Akashi, Toshiya Kishida, Hiroyuki Furukawa
  • Publication number: 20080239441
    Abstract: The present mirror device for suppressing PDL on the assumption of multiple modes of angles of input light and output light to movable mirrors with respect to the crystal axis of a crystal member at the time light passes through the crystal member. The mirror device includes a mirror system 2 and a flat-shaped crystal member 3 which is arranged in such a manner that a first angle is not larger than a second angle. The crystal member is constructed in such a manner that a third angle is substantially equal to a half of a fourth angle.
    Type: Application
    Filed: February 20, 2008
    Publication date: October 2, 2008
    Applicant: Fujitsu Limited
    Inventors: Hirofumi AOTA, Kohei Shibata, Tamotsu Akashi, Tsuyoshi Yamamoto