Patents by Inventor Tamotsu Akashi

Tamotsu Akashi 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: 20070290422
    Abstract: Disclosed is an electronic apparatus having a high-reliability vibration-proof structure for a wide temperature range. The electronic apparatus comprises a casing for storing a hard disk; and a rubber vibration isolator having projections on both faces thereof, which is disposed between the hard disk and the casing such that the projections have contact areas with the hard disk as well as with the casing and in which the contact area and an inverse number of Young's modulus are equal in the change rate caused due to temperature change. Accordingly, a spring constant can be maintained virtually constant without depending on the temperature change.
    Type: Application
    Filed: November 21, 2006
    Publication date: December 20, 2007
    Inventor: Tamotsu Akashi
  • Patent number: 7302133
    Abstract: There is provided an optical switch for reducing an apparatus size without making a structure for switching an output path complicated, wherein the first reflecting member and the micromirror array, which are optically coupled with the diffraction grating via the second reflecting member, are arranged at the same side relative to the diffraction grating.
    Type: Grant
    Filed: May 15, 2007
    Date of Patent: November 27, 2007
    Assignee: Fujitsu Limited
    Inventor: Tamotsu Akashi
  • Publication number: 20070211988
    Abstract: There is provided an optical switch for reducing an apparatus size without making a structure for switching an output path complicated, wherein the first reflecting member and the micromirror array, which are optically coupled with the diffraction grating via the second reflecting member, are arranged at the same side relative to the diffraction grating.
    Type: Application
    Filed: May 15, 2007
    Publication date: September 13, 2007
    Applicant: Fujitsu Limited
    Inventor: Tamotsu AKASHI
  • Patent number: 7263254
    Abstract: The present invention provides an optical switch for restricting a reduction in an optical coupling efficiency to an output optical path, which comprises a first spectral unit, a second spectral unit for further spectrally diffracting a plurality of wavelength components spectrally diffracted in the first spectral unit, a plurality of movable mirrors capable of reflecting the plurality of wavelength components spectrally diffracted in the second spectral unit respectively and directing the same in different directions, and a controller for compensating for deviation angles relative to optical axes of the plurality of wavelength components spectrally diffracted in the second spectral unit through setting of angles of reflecting faces in the plurality of movable mirrors.
    Type: Grant
    Filed: June 9, 2005
    Date of Patent: August 28, 2007
    Assignee: Fujitsu Limited
    Inventors: Shinji Yamashita, Tsuyoshi Yamamoto, Tamotsu Akashi, Kohei Shibata, Hirofumi Aota
  • Publication number: 20070153352
    Abstract: A housing 20 is equipped for supporting, from a side, a platform of a wavelength selection device comprising an input/output port 10, a collimator 11, an expanding optical system 12, a spectroscopic element, a collecting optical system 14 and a micro electro mechanical system (MEMS) mirror array 15. Because the above noted optical member is supported from the side only, influences of a thermal expansion is limited to the height direction of the optical member and the optical axis direction. By these aspects, the influence of thermal expansion is limited to a two-dimensional from a common three-dimensional, thereby enabling a design of a countermeasure to an influence of a thermal expansion. Also, the support from the side does not create a dead space thereby making the wavelength selection device compact.
    Type: Application
    Filed: April 28, 2006
    Publication date: July 5, 2007
    Inventors: Kohei Shibata, Nobuhiro Fukushima, Tamotsu Akashi, Toshiya Kishida, Tsuyoshi Yamamoto, Hirofumi Aota, Shinji Yamashita, Shinichi Takeuchi, Hiroyuki Furukawa, Yoshinobu Kubota
  • Patent number: 7233716
    Abstract: There is provided an optical switch for reducing an apparatus size without making a structure for switching an output path complicated, wherein the first reflecting member and the micromirror array, which are optically coupled with the diffraction grating via the second reflecting member, are arranged at the same side relative to the diffraction grating.
    Type: Grant
    Filed: June 15, 2005
    Date of Patent: June 19, 2007
    Assignee: Fujitsu Limited
    Inventor: Tamotsu Akashi
  • Publication number: 20070077003
    Abstract: A wavelength selective optical switch of the present invention separates a WDM light emitted from an input port of an input and output optical system, according to wavelengths, by a diffraction grating, and thereafter, condenses the lights of respective wavelengths on MEMS mirrors respectively corresponding to the respective wavelengths, in a mirror array, to reflect them by a condenser optical system, to thereby switch optical paths for the respective lights. The condenser optical system is configured by combining a plurality of lenses whose focal distances are different from each other, and positions in an optical axis direction of the lenses are adjustable by a slide mechanism. Thus, despite an error in the focal distances of the condenser lenses, in a mounting angle of a spectral element or the like, a beam pitch at the condensing positions of the lights of respective wavelengths can be coincident with a mirror pitch in the mirror array.
    Type: Application
    Filed: December 30, 2005
    Publication date: April 5, 2007
    Applicant: FUJITSU LIMITED
    Inventors: Hirofumi Aota, Kohei Shibata, Tamotsu Akashi, Shinji Yamashita, Tsuyoshi Yamamoto, Shinichi Takeuchi, Yoshinobu Kubota, Nobuhiro Fukushima, Hiroyuki Furukawa, Toshiya Kishida
  • Publication number: 20060239608
    Abstract: There is provided an optical switch for reducing an apparatus size without making a structure for switching an output path complicated, wherein the first reflecting member and the micromirror array, which are optically coupled with the diffraction grating via the second reflecting member, are arranged at the same side relative to the diffraction grating.
    Type: Application
    Filed: June 15, 2005
    Publication date: October 26, 2006
    Applicant: Fujitsu Limited
    Inventor: Tamotsu Akashi
  • Publication number: 20060222290
    Abstract: The present invention provides an optical switch for restricting a reduction in an optical coupling efficiency to an output optical path, which comprises a first spectral unit, a second spectral unit for further spectrally diffracting a plurality of wavelength components spectrally diffracted in the first spectral unit, a plurality of movable mirrors capable of reflecting the plurality of wavelength components spectrally diffracted in the second spectral unit respectively and directing the same in different directions, and a controller for compensating for deviation angles relative to optical axes of the plurality of wavelength components spectrally diffracted in the second spectral unit through setting of angles of reflecting faces in the plurality of movable mirrors.
    Type: Application
    Filed: June 9, 2005
    Publication date: October 5, 2006
    Applicant: Fujitsu Limited
    Inventors: Shinji Yamashita, Tsuyoshi Yamamoto, Tamotsu Akashi, Kohei Shibata, Hirofumi Aota
  • Publication number: 20060140536
    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: Application
    Filed: March 18, 2005
    Publication date: June 29, 2006
    Applicant: Fujitsu Limited
    Inventors: Hirofumi Aota, Tamotsu Akashi
  • Publication number: 20060093257
    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: Application
    Filed: January 28, 2005
    Publication date: May 4, 2006
    Applicant: FUJITSU LIMITED
    Inventors: Hirofumi Aota, Tamotsu Akashi
  • Publication number: 20060093256
    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: Application
    Filed: January 24, 2005
    Publication date: May 4, 2006
    Applicant: Fujitsu Limited
    Inventors: Shinji Yamashita, Tsuyoshi Yamamoto, Tamotsu Akashi, Kohei Shibata, Hirofumi Aota, Osamu Tsuboi
  • Publication number: 20060093263
    Abstract: A collimator array includes a substrate; a plurality of lenses formed on one face of the substrate; and a plurality of projecting parts, each of which is formed on a portion corresponding to the lens on the other face of the substrate, respectively and is fusion-connected to an optical fiber, respectively; wherein an area of the fusion-connected face of the projecting part with respect to the optical fiber is set to be larger than a cross sectional area of the optical fiber. Thereby, it is possible to provide a collimator having fewer variations in an output beam angle and a diameter of an output beam and having excellent strength, and a method for manufacturing the same.
    Type: Application
    Filed: January 25, 2005
    Publication date: May 4, 2006
    Applicant: Fujitsu Limited
    Inventors: Tamotsu Akashi, Tsuyoshi Yamamoto, Shinji Yamashita, Kohei Shibata, Hirofumi Aota
  • Publication number: 20060088317
    Abstract: A mirror controller of an optical switch comprises a signal generator (10, 82, 83) for passing the optical signal on the same light path as the one for optical communication using the optical switch, and an image analyzer (15, 16, 81) detecting the optical signal as the light scattered by at least one of tilt mirrors (111, 123) and an output collimator array (14). The image analyzer detects the position of the light beam image as a control position (121, 141, 85) based on the scattered light, and controls the tilt mirrors in such a manner that the detected control position coincides with the predetermined desired target position (122, 142, 84, 86) on at least one of the tilt mirrors and the output collimator array. The mirror controller can realize the connection test of the optical signal between input and output with high accuracy and reliability.
    Type: Application
    Filed: January 21, 2005
    Publication date: April 27, 2006
    Applicant: FUJITSU LIMITED
    Inventors: Yuji Ishii, Kazuyuki Mori, Tamotsu Akashi, Yoshio Sakai
  • Patent number: 7031565
    Abstract: Disclosed is a photonic switch that includes a plurality of optical-path switching means having movable light reflecting portions that guide light from each of a plurality of input ports to any output port among a plurality of output ports. Each of the optical-path switching means is made to produce a specific loss so as to reduce path-to-path variations in loss along the paths from the input to the output ports. Specifically, loss along a path is the total of loss based upon optical path length and loss produced by the optical-path switching means. A specific loss is produced by each of the optical-path switching means in such a manner that total loss is equalized from path to path.
    Type: Grant
    Filed: January 7, 2005
    Date of Patent: April 18, 2006
    Assignee: Fujitsu Limited
    Inventors: Tamotsu Akashi, Tsuyoshi Yamamoto
  • Publication number: 20050191057
    Abstract: An optical transceiver module is constituted so as to have an optical transmission module, an optical receiving module, a drive circuit board for driving the optical transmission module and the optical receiving module, and short-circuit means which induces an electrical short circuit between housings of the respective modules or induces an electrical short circuit between ground (GND) terminals of the respective modules on the module sides with respect to the drive circuit board. As a result, in the optical transceiver module, stray capacitance and stray inductance in lead pins, housings, and internal components of optical devices, such as an LD and a PD, are removed, thereby suppressing fluctuations in the potential (GND) of an LD housing which arise during high-frequency driving operation, as well as considerably suppressing electrical crosstalk between the transmission and receiving modules.
    Type: Application
    Filed: June 21, 2004
    Publication date: September 1, 2005
    Applicant: Fujitsu Limited
    Inventors: Ken-ichi Nakamoto, Tamotsu Akashi, Kazuyuki Mori, Shin-ichi Sakuramoto
  • Patent number: 6925222
    Abstract: Disclosed is a photonic switch that includes a plurality of optical-path switching means having movable light reflecting portions that guide light from each of a plurality of input ports to any output port among a plurality of output ports. Each of the optical-path switching means is made to produce a specific loss so as to reduce path-to-path variations in loss along the paths from the input to the output ports. Specifically, loss along a path is the total of loss based upon optical path length and loss produced by the optical-path switching means. A specific loss is produced by each of the optical-path switching means in such a manner that total loss is equalized from path to path.
    Type: Grant
    Filed: October 7, 2002
    Date of Patent: August 2, 2005
    Assignee: Fujitsu Limited
    Inventors: Tamotsu Akashi, Tsuyoshi Yamamoto
  • Publication number: 20050135734
    Abstract: Disclosed is a photonic switch that includes a plurality of optical-path switching means having movable light reflecting portions that guide light from each of a plurality of input ports to any output port among a plurality of output ports. Each of the optical-path switching means is made to produce a specific loss so as to reduce path-to-path variations in loss along the paths from the input to the output ports. Specifically, loss along a path is the total of loss based upon optical path length and loss produced by the optical-path switching means. A specific loss is produced by each of the optical-path switching means in such a manner that total loss is equalized from path to path.
    Type: Application
    Filed: January 7, 2005
    Publication date: June 23, 2005
    Applicant: Fujitsu Limited
    Inventors: Tamotsu Akashi, Tsuyoshi Yamamoto
  • Patent number: 6901222
    Abstract: Disclosed herein is a terminal device including a photodetector, amplitude detecting circuit, light source, drive circuit, and control circuit. The photodetector receives a first optical signal. The amplitude detecting circuit detects the amplitude of an output from the photodetector. The drive circuit supplies a drive current to the light source so that the light source outputs a second optical signal. The control circuit decreases and increases the drive current according to an increase and decrease in the amplitude detected by the amplitude detecting circuit, respectively. In the case that this terminal device is used with another terminal device to construct a network, the dynamic range of the other terminal device can be reduced. Accordingly, the use of this terminal device can improve the extensibility of the network.
    Type: Grant
    Filed: December 5, 2001
    Date of Patent: May 31, 2005
    Assignee: Fujitsu Limited
    Inventors: Shinji Yamashita, Kazuyuki Mori, Tamotsu Akashi
  • Patent number: 6771426
    Abstract: In an input-output optical system of spatially optical coupled type, a spacer is provided in at least one of input and output optical systems and interposed between a lens array block and a fiber block without blocking an optical path for ensuring a distance corresponding to a focal distance of collimating lenses. As a result, highly-accurate, highly-stable alignment of an optical axis can be readily realized.
    Type: Grant
    Filed: January 15, 2003
    Date of Patent: August 3, 2004
    Assignee: Fujitsu Limited
    Inventors: Tsuyoshi Yamamoto, Tamotsu Akashi, Shinichi Takeuchi