Patents by Inventor Yoichi Oikawa

Yoichi Oikawa 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: 20080166128
    Abstract: An optical apparatus comprising, converting units converting electrical signals into signal lights with different wavelength, polarization control units controlling polarizing states of the signal lights into polarization controlled lights respectively, an optical multiplexer multiplexing the polarization controlled lights into a multiplexed light, an optical branching unit branching the multiplexed light and outputting a branched light, a polarizing unit extracting only signal lights of the specified polarizing state from the branched light into an extracted light, and a control unit detecting intensity of the extracted light. Pilot signals are applied to modulate the electrical signals or the polarization controls. The polarization control units controls the polarizing states of the signal lights based on the pilot signal frequencies of the detection result by the control unit.
    Type: Application
    Filed: December 4, 2007
    Publication date: July 10, 2008
    Applicant: Fujitsu Limited
    Inventors: Takashi TOYOMAKI, Noriaki Mizuguchi, Yoichi Oikawa
  • Patent number: 7379636
    Abstract: An optical switch having a plurality of switch cells. The optical switch has n inputs (n is a natural number) and m outputs (m is a natural number). The optical switch has a unit size defined as the distance between any two adjacent ones of the switch cells. The optical switch comprises a substrate having a switch size of K×L (K is an integer satisfying n?K, and L is an integer satisfying m?L), first and second mirrors parallel to each other and perpendicular to a principal surface of the substrate, and an optical unit providing a plurality of input optical paths for the n inputs and a plurality of output optical paths for the m outputs. The plurality of input optical paths are inclined relative to the first and second mirrors, and the plurality of output optical paths are inclined relative to the first and second mirrors. Each switch cell comprises a switch mirror provided movably relative to the substrate. With this configuration, the path dependence of loss is substantially eliminated.
    Type: Grant
    Filed: December 18, 2006
    Date of Patent: May 27, 2008
    Assignee: Fujitsu Limited
    Inventors: Yoichi Oikawa, Satoshi Kuroyanagi
  • Publication number: 20070297718
    Abstract: The distance between an optical diffraction device and a focusing lens, and the coefficient of the focal length change of the focusing lens, are adjusted based on the calculation expression of wavelength identification errors in light of temperature change of a member making up light receiving means (e.g., PD array), thereby performing correction of wavelength identification errors, whereby optical wavelength identification can be performed with high precision even when the temperature changes.
    Type: Application
    Filed: April 9, 2007
    Publication date: December 27, 2007
    Applicant: FUJITSU LIMITED
    Inventor: Yoichi Oikawa
  • Patent number: 7269314
    Abstract: The present invention is a dispersion compensation device capable of varying dispersion compensation amount with a simple configuration. The device includes a first mode light conversion section capable of converting input light into light of higher mode, a dispersion compensation section capable of performing dispersion compensation on the higher mode light outputted from the first mode light conversion section corresponding to the status of mode of the higher mode light, a second mode light conversion section capable of converting the light of higher mode dispersion-compensated in the dispersion compensation section into light of original mode, and a mode control section capable of variably controlling the status of mode of the higher mode light converted in the first mode light conversion section, and controlling to convert the higher mode light from the dispersion compensation section to the light of original mode in the second mode light conversion section.
    Type: Grant
    Filed: February 3, 2005
    Date of Patent: September 11, 2007
    Assignee: Fujitsu Limited
    Inventor: Yoichi Oikawa
  • Publication number: 20070098321
    Abstract: An optical switch having a plurality of switch cells. The optical switch has n inputs (n is a natural number) and m outputs (m is a natural number). The optical switch has a unit size defined as the distance between any two adjacent ones of the switch cells. The optical switch comprises a substrate having a switch size of K×L (K is an integer satisfying n?K, and L is an integer satisfying m?L), first and second mirrors parallel to each other and perpendicular to a principal surface of the substrate, and an optical unit providing a plurality of input optical paths for the n inputs and a plurality of output optical paths for the m outputs. The plurality of input optical paths are inclined relative to the first and second mirrors, and the plurality of output optical paths are inclined relative to the first and second mirrors. Each switch cell comprises a switch mirror provided movably relative to the substrate. With this configuration, the path dependence of loss is substantially eliminated.
    Type: Application
    Filed: December 18, 2006
    Publication date: May 3, 2007
    Applicant: Fujitsu Limited
    Inventors: Yoichi Oikawa, Satoshi Kuroyanagi
  • Patent number: 7206476
    Abstract: An optical switch having a plurality of switch cells. The optical switch has n inputs (n is a natural number) and m outputs (m is a natural number). The optical switch has a unit size defined as the distance between any two adjacent ones of the switch cells. The optical switch comprises a substrate having a switch size of K×L (K is an integer satisfying n?K, and L is an integer satisfying m?L), first and second mirrors parallel to each other and perpendicular to a principal surface of the substrate, and an optical unit providing a plurality of input optical paths for the n inputs and a plurality of output optical paths for the m outputs. The plurality of input optical paths are inclined relative to the first and second mirrors, and the plurality of output optical paths are inclined relative to the first and second mirrors. Each switch cell comprises a switch mirror provided movably relative to the substrate. With this configuration, the path dependence of loss is substantially eliminated.
    Type: Grant
    Filed: May 6, 2005
    Date of Patent: April 17, 2007
    Assignee: Fujitsu Limited
    Inventors: Yoichi Oikawa, Satoshi Kuroyanagi
  • Patent number: 7151866
    Abstract: An optical device module includes an optical device with a plurality of electrodes disposed at predetermined positions, a substrate disposed oppositely to the optical device and with wiring patterns for connecting to the electrodes, and a wiring which connects the electrodes to the wiring patterns.
    Type: Grant
    Filed: March 24, 2004
    Date of Patent: December 19, 2006
    Assignee: Fujitsu Limited
    Inventors: Yoichi Oikawa, Hirofumi Aota, Kazuaki Akimoto, Hideyuki Miyata, Yumi Nakazawa, legal representative, Tadao Nakazawa, deceased
  • Patent number: 7106927
    Abstract: Optical cross-connect apparatus including first wavelength converters converting m different wavelengths ?1 through ?m contained in n WDM input optical signals into 2m wavelengths ?1 through ?2m; a first wavelength cross-connector performing cross-connection according to wavelengths, separating the optical signals wavelength-converted by the first wavelength converters into 2m wavelengths combining optical signals with the 2m separated wavelengths; second wavelength converters converting the 2m wavelengths contained in the optical signals cross-connected by the first wavelength cross-connector into 2m wavelengths; a second wavelength cross-connector performing cross-connection according to wavelengths separating the optical signals wavelength-converted by the second wavelength converters into 2m wavelengths and combining optical signals with the 2m separated wavelengths; and third wavelength converters converting the 2m wavelengths ?1 through ?2m in the optical signals cross-connected by the second wavelength
    Type: Grant
    Filed: February 20, 2004
    Date of Patent: September 12, 2006
    Assignee: Fujitsu Limited
    Inventor: Yoichi Oikawa
  • Publication number: 20060198583
    Abstract: A wavelength selective switch of the invention, separates WDM light coming out from an input fiber of a fiber collimator array according to its wavelength, in a diffraction grating, and reflects each wavelength channel proceeding in different directions by MEMS mirrors corresponding to a mirror array. In the MEMS mirrors, the angles of their reflecting surfaces are set corresponding to the location of the output port which is set in the output address of the wavelength channel to be injected. For each of the wavelength channels that reach the target output port, one part of each is reflected by the end face of an output fiber, and the reflected light is returned to the input port, and sent to a channel monitor via an optical circulator, so that the optical power corresponding to each wavelength channel is monitored.
    Type: Application
    Filed: June 22, 2005
    Publication date: September 7, 2006
    Applicant: FUJITSU LIMITED
    Inventors: Yoichi Oikawa, Kazuaki Akimoto
  • Publication number: 20060127001
    Abstract: The present invention is a dispersion compensation device capable of varying dispersion compensation amount with a simple configuration. The device includes a first mode light conversion section capable of converting input light into light of higher mode, a dispersion compensation section capable of performing dispersion compensation on the higher mode light outputted from the first mode light conversion section corresponding to the status of mode of the higher mode light, a second mode light conversion section capable of converting the light of higher mode dispersion-compensated in the dispersion compensation section into light of original mode, and a mode control section capable of variably controlling the status of mode of the higher mode light converted in the first mode light conversion section, and controlling to convert the higher mode light from the dispersion compensation section to the light of original mode in the second mode light conversion section.
    Type: Application
    Filed: February 3, 2005
    Publication date: June 15, 2006
    Applicant: Fujitsu Limited
    Inventor: Yoichi Oikawa
  • Patent number: 6999648
    Abstract: An optical cross-connect apparatus that realizes high throughput in optical cross-connection by performing large-scale switching. An input optical signal processing section converts wavelengths contained in each input WDM signal into wavelengths the number of which is equal to the number of WDM signals, compresses the pulse widths of the WDM signals by dividing the pulse widths by the number of the wavelengths contained in each input WDM signal, and performs a phase shift so that the phases of a plurality of compressed signal will not be the same. A wavelength switching section includes passive optical devices and distributes the optical signals processed by the input optical signal processing section according to wavelengths. An output optical signal processing section converts wavelengths contained in the optical signals distributed by the wavelength switching section into wavelengths recognized from the phases of the optical signals, expands the pulse widths of the optical signals, and outputs WDM signals.
    Type: Grant
    Filed: February 26, 2004
    Date of Patent: February 14, 2006
    Assignee: Fujitsu Limited
    Inventors: Yoichi Oikawa, Makoto Murakami, Takehisa Ishikawa
  • Publication number: 20050220397
    Abstract: In a CWDM optical transmission system of the present invention, in place of an optical signal of at least one wave among a plurality of optical signals corresponding to a CWDM system, a DWDM light output from an additional light transmission unit of a DWDM system is given to a multiplexer via a variable optical attenuator, and multiplexed with the optical signals corresponding to CWDM, to be sent out to a transmission path. At this time, the total power of the DWDM light sent out to the transmission path, is attenuated by the variable optical attenuator, so as to be approximately equal to the power per one wavelength of the CWDM light. On an optical reception terminal, the light propagated through the transmission path is demultiplexed by a demultiplexer, and the DWDM light corresponding to the additional wavelengths is amplified by an optical amplifier and thereafter, received by an additional light reception unit.
    Type: Application
    Filed: January 25, 2005
    Publication date: October 6, 2005
    Applicant: Fujitsu Limited
    Inventors: Yoichi Oikawa, Takashi Toyomaki, Tomoyuki Ohtsuka
  • Publication number: 20050196098
    Abstract: An optical switch having a plurality of switch cells. The optical switch has n inputs (n is a natural number) and m outputs (m is a natural number). The optical switch has a unit size defined as the distance between any two adjacent ones of the switch cells. The optical switch comprises a substrate having a switch size of K×L (K is an integer satisfying n?K, and L is an integer satisfying m?L), first and second mirrors parallel to each other and perpendicular to a principal surface of the substrate, and an optical unit providing a plurality of input optical paths for the n inputs and a plurality of output optical paths for the m outputs. The plurality of input optical paths are inclined relative to the first and second mirrors, and the plurality of output optical paths are inclined relative to the first and second mirrors. Each switch cell comprises a switch mirror provided movably relative to the substrate. With this configuration, the path dependence of loss is substantially eliminated.
    Type: Application
    Filed: May 6, 2005
    Publication date: September 8, 2005
    Applicant: Fujitsu Limited
    Inventors: Yoichi Oikawa, Satoshi Kuroyanagi
  • Patent number: 6907154
    Abstract: An optical switch having a plurality of switch cells. The optical switch has n inputs (n is a natural number) and m outputs (m is a natural number). The optical switch has a unit size defined as the distance between any two adjacent ones of the switch cells. The optical switch comprises a substrate having a switch size of K×L (K is an integer satisfying n?K, and L is an integer satisfying m?L), first and second mirrors parallel to each other and perpendicular to a principal surface of the substrate, and an optical unit providing a plurality of input optical paths for the n inputs and a plurality of output optical paths for the m outputs. The plurality of input optical paths are inclined relative to the first and second mirrors, and the plurality of output optical paths are inclined relative to the first and second mirrors. Each switch cell comprises a switch mirror provided movably relative to the substrate. With this configuration, the path dependence of loss is substantially eliminated.
    Type: Grant
    Filed: August 9, 2001
    Date of Patent: June 14, 2005
    Assignee: Fujitsu Limited
    Inventors: Yoichi Oikawa, Satoshi Kuroyanagi
  • Patent number: 6901179
    Abstract: Disclosed herein is an optical switch including a plurality of switch cells arranged in the form of an n×n matrix (n is an integer), each switch cell having first and second input ends and first and second output ends, and 2(n?1) reflection cells. The plural switch cells are selectively driven so that one of the first and second input ends of the switch cells in the first column is optically connected to one of the first and second output ends of the switch cells in the n-th column. (n?1) ones of the 2(n?1) reflection cells are arranged so as to optically connect the first output end of the switch cell in the first row, the i-th column (i is an integer satisfying 1?i?(n?1)) to the first input end of the switch cell in the first row, the (i+1)-th column.
    Type: Grant
    Filed: April 6, 2004
    Date of Patent: May 31, 2005
    Assignee: Fujitsu Limited
    Inventor: Yoichi Oikawa
  • Publication number: 20050105908
    Abstract: An optical repeater which includes a wavelength converter and a bit rate converter. The wavelength converter converts a wavelength of an optical signal from a first optical network to a wavelength of a second optical network. The bit rate converter converts a bit rate of the optical signal from the first optical network to a bit rate of the second optical network. The optical repeater transmits the optical signal from the first optical network to the second optical network at the converted bit rate and wavelength.
    Type: Application
    Filed: September 16, 2004
    Publication date: May 19, 2005
    Applicant: Fujitsu Limited
    Inventor: Yoichi Oikawa
  • Publication number: 20050094143
    Abstract: The invention aims to provide a miniaturized polarization measuring apparatus which can measure the polarization of input signal light with high accuracy, even in an optical system where a plurality of light receiving elements are arranged adjacent to each other.
    Type: Application
    Filed: May 12, 2004
    Publication date: May 5, 2005
    Applicant: Fujitsu Limited
    Inventors: Teruhiro Kubo, Yoichi Oikawa
  • Publication number: 20050089275
    Abstract: An optical device module includes an optical device with a plurality of electrodes disposed at predetermined positions, a substrate disposed oppositely to the optical device and with wiring patterns for connecting to the electrodes, and a wiring which connects the electrodes to the wiring patterns.
    Type: Application
    Filed: March 24, 2004
    Publication date: April 28, 2005
    Applicant: FUJITSU LIMITED
    Inventors: Yoichi Oikawa, Hirofumi Aota, Kazuaki Akimoto, Hideyuki Miyata, Yumi Nakazawa, Tadao Nakazawa
  • Publication number: 20050089282
    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: Application
    Filed: March 22, 2004
    Publication date: April 28, 2005
    Applicant: FUJITSU LIMITED
    Inventors: Yoichi Oikawa, Hirofumi Aota, Kazuaki Akimoto, Hideyuki Miyata, Tadao Nakazawa, Yumi Nakazawa
  • Patent number: 6819828
    Abstract: Disclosed herein is a method including the steps of wavelength division multiplexing a plurality of optical signals having different wavelengths to obtain resultant WDM signal light; transmitting the WDM signal light by an optical fiber transmission line; supplying reference light having a predetermined wavelength to the optical fiber transmission line; generating four-wave mixing in the optical fiber transmission line by the interaction of the WDM signal light and the reference light; detecting the power of light generated as the result of the four-wave mixing; and controlling the power of the WDM signal light to be supplied to the optical fiber transmission line according to the power detected. According to this method, the effect of four-wave mixing can be suppressed.
    Type: Grant
    Filed: September 26, 2001
    Date of Patent: November 16, 2004
    Assignee: Fujitsu Limited
    Inventors: Tsukasa Takahashi, Toshihiro Ohtani, Yoichi Oikawa