Patents by Inventor Masataka Shirasaki

Masataka Shirasaki 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).

  • Patent number: 6717731
    Abstract: An optical apparatus for producing chromatic dispersion. The apparatus includes a virtually imaged phased array (VIPA) generator, a mirror and a lens. The VIPA generator receives an input light at a respective wavelength and produces a corresponding collimated output light traveling from the VIPA generator in a direction determined by the wavelength of the input light, the output light thereby being spatially distinguishable from an output light produced for an input light at a different wavelength. The mirror has a cone shape, or a modified cone shape. The lens focuses the output light traveling from the VIPA generator onto the mirror so that the mirror reflects the output light. The reflected light is directed by the lens back to the VIPA generator. In this manner, the apparatus provides chromatic dispersion to the input light.
    Type: Grant
    Filed: October 1, 2002
    Date of Patent: April 6, 2004
    Assignees: Fujitsu Limited, Avanex Corporation
    Inventors: Masataka Shirasaki, Simon Cao
  • Publication number: 20030214737
    Abstract: An optical apparatus for producing chromatic dispersion. The apparatus includes a virtually imaged phased array (VIPA) generator, a mirror and a lens. The VIPA generator receives an input light at a respective wavelength and produces a corresponding collimated output light traveling from the VIPA generator in a direction determined by the wavelength of the input light, the output light thereby being spatially distinguishable from an output light produced for an input light at a different wavelength. The mirror has a cone shape, or a modified cone shape. The lens focuses the output light traveling from the VIPA generator onto the mirror so that the mirror reflects the output light. The reflected light is directed by the lens back to the VIPA generator. In this manner, the apparatus provides chromatic dispersion to the input light.
    Type: Application
    Filed: June 12, 2003
    Publication date: November 20, 2003
    Applicant: Fujitsu Limited
    Inventors: Masataka Shirasaki, Simon Cao
  • Publication number: 20030179989
    Abstract: An optical wavelength division multiplexed system uses wavelength splitters to split channels included in input light into different paths within the system. Odd-numbered channels are split into one path, and even-numbered channels are split into another path, providing increased isolation between channels. Using filters, the system then drops one or more of the isolated, split channels into paths referred to as dropped paths and allows the remaining channels to continue through the filters into output paths. The dropped paths are then combined into one, common dropped path, and the output paths are also combined into one, common output path.
    Type: Application
    Filed: March 19, 2003
    Publication date: September 25, 2003
    Applicant: FUJITSU LIMITED
    Inventor: Masataka Shirasaki
  • Patent number: 6607278
    Abstract: An optical apparatus for producing chromatic dispersion. The apparatus includes a virtually imaged phased array (VIPA) generator, a mirror and a lens. The VIPA generator receives an input light at a respective wavelength and produces a corresponding collimated output light traveling from the VIPA generator in a direction determined by the wavelength of the input light, the output light thereby being spatially distinguishable from an output light produced for an input light at a different wavelength. The mirror has a cone shape, or a modified cone shape. The lens focuses the output light traveling from the VIPA generator onto the mirror so that the mirror reflects the output light. The reflected light is directed by the lens back to the VIPA generator. In this manner, the apparatus provides chromatic dispersion to the input light.
    Type: Grant
    Filed: September 10, 2002
    Date of Patent: August 19, 2003
    Assignees: Fujitsu Limited, Avanex Corporation
    Inventors: Masataka Shirasaki, Simon Cao
  • Publication number: 20030081318
    Abstract: An optical apparatus for producing chromatic dispersion. The apparatus includes a virtually imaged phased array (VIPA) generator, a mirror and a lens. The VIPA generator receives an input light at a respective wavelength and produces a corresponding collimated output light traveling from the VIPA generator in a direction determined by the wavelength of the input light, the output light thereby being spatially distinguishable from an output light produced for an input light at a different wavelength. The mirror has a cone shape, or a modified cone shape. The lens focuses the output light traveling from the VIPA generator onto the mirror so that the mirror reflects the output light. The reflected light is directed by the lens back to the VIPA generator. In this manner, the apparatus provides chromatic dispersion to the input light.
    Type: Application
    Filed: October 1, 2002
    Publication date: May 1, 2003
    Applicant: FUJITSU LIMITED
    Inventors: Masataka Shirasaki, Simon Cao
  • Patent number: 6556742
    Abstract: An optical wavelength division multiplexed system uses wavelength splitters to split channels included in input light into different paths within the system. Odd-numbered channels are split into one path, and even-numbered channels are split into another path, providing increased isolation between channels. Using filters, the system then drops one or more of the isolated, split channels into paths referred to as dropped paths and allows the remaining channels to continue through the filters into output paths. The dropped paths are then combined into one, common dropped path, and the output paths are also combined into one, common output path.
    Type: Grant
    Filed: November 4, 1998
    Date of Patent: April 29, 2003
    Assignee: Fujitsu Limited
    Inventor: Masataka Shirasaki
  • Publication number: 20030053783
    Abstract: The invention relates to apparatus and methods for reducing the temperature sensitivity of optical fibers. According to one embodiment, the temperature insensitive optical fiber includes a core having a temperature dependent optical length and a cladding surrounding the core. The temperature insensitive fiber further includes an expansion control coating substantially surrounding the cladding. The expansion control coating has a coefficient of thermal expansion and is adapted to modify the temperature dependence of the optical length. The temperature insensitive optical fiber can be used in a fiber interferometer to substantially compensate the interferometer output signal over an operating temperature range. The temperature insensitive optical fiber can also be adapted for fiber diffraction gratings.
    Type: Application
    Filed: September 18, 2001
    Publication date: March 20, 2003
    Inventor: Masataka Shirasaki
  • Publication number: 20030021046
    Abstract: Various configurations of a virtually imaged phased array (VIPA) generator in combination with a mirror to compensate for chromatic dispersion. A VIPA generator produces a light traveling from the VIPA generator. In some embodiments, a variable curvature mirror is positioned to reflect the light back to the VIPA generator. A rotation axis around which the mirror is rotated and a translation path for the rotation axis are provided, to change the curvature of the mirror where the output light is reflected. In other embodiments, a plurality of mirrors have different surface curvatures. A holder has a rotation axis and holds the plurality of mirrors equidistantly from the rotation axis. The holder is rotatable around the rotation axis to bring a different, respective mirror in position to reflect light produced by a VIPA generator back to the VIPA generator. In other embodiments, a rotating mirror is rotatable about a rotation axis to reflect light produced by a VIPA generator to a respective fixed mirror.
    Type: Application
    Filed: September 24, 2002
    Publication date: January 30, 2003
    Applicant: FUJITSU LIMITED
    Inventors: Simon Xiaofan Cao, Masataka Shirasaki
  • Publication number: 20030012250
    Abstract: The invention relates to apparatus and methods for tuning the wavelength of a laser. According to one embodiment, the wavelength tunable filter includes a first wavelength selective element having a first thickness, a first refractive index and a first spectral response having a plurality of transmission peaks having an associated first period. The filter also includes a second wavelength selective element having a second thickness, a second refractive index and a second spectral response having a plurality of transmission peaks having an associated second period. Additionally, the filter includes a control module to vary at least one of the first thickness, the second thickness, the first refractive index, and the second refractive index such that one of the plurality of transmission peaks of the first spectral response substantially overlaps one of the plurality of transmission peaks of the second spectral response.
    Type: Application
    Filed: June 25, 2001
    Publication date: January 16, 2003
    Inventor: Masataka Shirasaki
  • Publication number: 20030007264
    Abstract: An optical apparatus for producing chromatic dispersion. The apparatus includes a virtually imaged phased array (VIPA) generator, a mirror and a lens. The VIPA generator receives an input light at a respective wavelength and produces a corresponding collimated output light traveling from the VIPA generator in a direction determined by the wavelength of the input light, the output light thereby being spatially distinguishable from an output light produced for an input light at a different wavelength. The mirror has a cone shape, or a modified cone shape. The lens focuses the output light traveling from the VIPA generator onto the mirror so that the mirror reflects the output light. The reflected light is directed by the lens back to the VIPA generator. In this manner, the apparatus provides chromatic dispersion to the input light.
    Type: Application
    Filed: September 10, 2002
    Publication date: January 9, 2003
    Applicant: FUJITSU LIMITED
    Inventors: Masataka Shirasaki, Simon Cao
  • Publication number: 20030002784
    Abstract: The invention relates to an optical bandpass filter and a method for filtering an optical signal having a plurality of WDM component wavelengths. The optical bandpass filter includes a spectrally dispersive element and an optical module. The spectrally dispersive element is adapted to receive the optical signal and to provide a dispersed optical signal to the optical module. The optical module returns predetermined WDM component wavelengths to the spectrally dispersive element. The predetermined WDM component wavelengths are imaged to predetermined locations.
    Type: Application
    Filed: June 25, 2001
    Publication date: January 2, 2003
    Inventor: Masataka Shirasaki
  • Publication number: 20020196816
    Abstract: In one embodiment, the invention relates to a tunable laser system. The laser system includes a first optical path at a first wavelength having a first path length and a second optical path at a second wavelength having a second path length. The first and second optical paths partially overlap in a shared path region that is shorter than either the first or second path lengths. The first and second path lengths are substantially equal. The laser system also includes an optical modulator that is located within the shared path. The laser system selects a wavelength of an optical pulse according to a sequence of drive signals from the drive signal generator. In another embodiment the laser system additionally includes a Fabry-Perot filter located in one of the shared paths. In operation of this embodiment, the laser system generates a series of optical pulses of different wavelengths.
    Type: Application
    Filed: November 30, 2001
    Publication date: December 26, 2002
    Inventor: Masataka Shirasaki
  • Patent number: 6481861
    Abstract: Various configurations of a virtually imaged phased array (VIPA) generator in combination with a mirror to compensate for chromatic dispersion. A VIPA generator produces a light traveling from the VIPA generator. In some embodiments, a variable curvature mirror is positioned to reflect the light back to the VIPA generator. A rotation axis around which the mirror is rotated and a translation path for the rotation axis are provided, to change the curvature of the mirror where the output light is reflected. In other embodiments, a plurality of mirrors have different surface curvatures. A holder has a rotation axis and holds the plurality of mirrors equidistantly from the rotation axis. The holder is rotatable around the rotation axis to bring a different, respective mirror in position to reflect light produced by a VIPA generator back to the VIPA generator. In other embodiments, a rotating mirror is rotatable about a rotation axis to reflect light produced by a VIPA generator to a respective fixed mirror.
    Type: Grant
    Filed: December 19, 2001
    Date of Patent: November 19, 2002
    Assignees: Fujitsu Limited, Avanex Corporation
    Inventors: Simon Xiaofan Cao, Masataka Shirasaki
  • Patent number: 6478433
    Abstract: An optical apparatus for producing chromatic dispersion. The apparatus includes a virtually imaged phased array (VIPA) generator, a mirror and a lens. The VIPA generator receives an input light at a respective wavelength and produces a corresponding collimated output light traveling from the VIPA generator in a direction determined by the wavelength of the input light, the output light thereby being spatially distinguishable from an output light produced for an input light at a different wavelength. The mirror has a cone shape, or a modified cone shape. The lens focuses the output light traveling from the VIPA generator onto the mirror so that the mirror reflects the output light. The reflected light is directed by the lens back to the VIPA generator. In this manner, the apparatus provides chromatic dispersion to the input light.
    Type: Grant
    Filed: October 30, 2001
    Date of Patent: November 12, 2002
    Assignees: Fujitsu Limited, Avanex Corporation
    Inventors: Masataka Shirasaki, Simon Cao
  • Patent number: 6471361
    Abstract: An optical apparatus for producing chromatic dispersion. The apparatus includes a virtually imaged phased array (VIPA) generator, a mirror and a lens. The VIPA generator receives an input light at a respective wavelength and produces a corresponding collimated output light traveling from the VIPA generator in a direction determined by the wavelength of the input light, the output light thereby being spatially distinguishable from an output light produced for an input light at a different wavelength. The mirror has a cone shape, or a modified cone shape. The lens focuses the output light traveling from the VIPA generator onto the mirror so that the mirror reflects the output light. The reflected light is directed by the lens back to the VIPA generator. In this manner, the: apparatus provides chromatic dispersion to the input light. The modified cone shape of the mirror can be designed so that the apparatus provides a uniform chromatic dispersion to light in the.
    Type: Grant
    Filed: February 27, 2002
    Date of Patent: October 29, 2002
    Assignees: Fujitsu Limited, Avanex Corporation
    Inventors: Masataka Shirasaki, Simon Cao
  • Publication number: 20020114090
    Abstract: An optical apparatus for producing chromatic dispersion. The apparatus includes a virtually imaged phased array (VIPA) generator, a mirror and a lens. The VIPA generator receives an input light at a respective wavelength and produces a corresponding collimated output light traveling from the VIPA generator in a direction determined by the wavelength of the input light, the output light thereby being spatially distinguishable from an output light produced for an input light at a different wavelength. The mirror has a cone shape, or a modified cone shape. The lens focuses the output light traveling from the VIPA generator onto the mirror so that the mirror reflects the output light. The reflected light is directed by the lens back to the VIPA generator. In this manner, the apparatus provides chromatic dispersion to the input light.
    Type: Application
    Filed: February 27, 2002
    Publication date: August 22, 2002
    Applicant: FUJITSU LIMITED
    Inventors: Masataka Shirasaki, Simon Cao
  • Publication number: 20020093748
    Abstract: Various configurations of a virtually imaged phased array (VIPA) generator in combination with a mirror to compensate for chromatic dispersion. A VIPA generator produces a light traveling from the VIPA generator. In some embodiments, a variable curvature mirror is positioned to reflect the light back to the VIPA generator. A rotation axis around which the mirror is rotated and a translation path for the rotation axis are provided, to change the curvature of the mirror where the output light is reflected. In other embodiments, a plurality of mirrors have different surface curvatures. A holder has a rotation axis and holds the plurality of mirrors equidistantly from the rotation axis. The holder is rotatable around the rotation axis to bring a different, respective mirror in position to reflect light produced by a VIPA generator back to the VIPA generator. In other embodiments, a rotating mirror is rotatable about a rotation axis to reflect light produced by a VIPA generator to a respective fixed mirror.
    Type: Application
    Filed: December 19, 2001
    Publication date: July 18, 2002
    Applicant: FUJITSU LIMITED
    Inventors: Simon Xiaofan Cao, Masataka Shirasaki
  • Patent number: 6390633
    Abstract: An optical apparatus for producing chromatic dispersion. The apparatus includes a virtually imaged phased array (VIPA) generator, a mirror and a lens. The VIPA generator receives an input light at a respective wavelength and produces a corresponding collimated output light traveling from the VIPA generator in a direction determined by the wavelength of the input light, the output light thereby being spatially distinguishable from an output light produced for an input light at a different wavelength. The mirror has a cone shape, or a modified cone shape. The lens focuses the output light traveling from the VIPA generator onto the mirror so that the mirror reflects the output light. The reflected light is directed by the lens back to the VIPA generator. In this manner, the apparatus provides chromatic dispersion to the input light.
    Type: Grant
    Filed: June 8, 2001
    Date of Patent: May 21, 2002
    Assignees: Fujitsu Limited, Avanex Corporation
    Inventors: Masataka Shirasaki, Simon Cao
  • Publication number: 20020044364
    Abstract: An optical apparatus for producing chromatic dispersion. The apparatus includes a virtually imaged phased array (VIPA) generator, a mirror and a lens. The VIPA generator receives an input light at a respective wavelength and produces a corresponding collimated output light traveling from the VIPA generator in a direction determined by the wavelength of the input light, the output light thereby being spatially distinguishable from an output light produced for an input light at a different wavelength. The mirror has a cone shape, or a modified cone shape. The lens focuses the output light traveling from the VIPA generator onto the mirror so that the mirror reflects the output light. The reflected light is directed by the lens back to the VIPA generator. In this manner, the apparatus provides chromatic dispersion to the input light.
    Type: Application
    Filed: October 30, 2001
    Publication date: April 18, 2002
    Applicant: FUJITSU LIMITED
    Inventors: Masataka Shirasaki, Simon Cao
  • Publication number: 20020025109
    Abstract: An optical wavelength division multiplexed system uses wavelength splitters to split channels included in input light into different paths within the system. Odd-numbered channels are split into one path, and even-numbered channels are split into another path, providing increased isolation between channels. Using filters, the system then drops one or more of the isolated, split channels into paths referred to as dropped paths and allows the remaining channels to continue through the filters into output paths. The dropped paths are then combined into one, common dropped path, and the output paths are also combined into one, common output path.
    Type: Application
    Filed: November 4, 1998
    Publication date: February 28, 2002
    Inventor: MASATAKA SHIRASAKI