Patents by Inventor Xiaofan Cao

Xiaofan Cao 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: 7193778
    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: August 9, 2004
    Date of Patent: March 20, 2007
    Assignee: Fujitsu Limited
    Inventors: Simon Xiaofan Cao, Masataka Shirasaki
  • Patent number: 7016610
    Abstract: A self-adjusting optical add-drop multiplexer monitors the power in a drop signal and attenuates the power in an add signal to match the power in express WDM channels (signals). When used in a fiber network, and more particularly, in a metro network, the deleterious effects of optical amplification are reduced. Power attenuation is also used in an optical switching assembly particularly useful in two-fiber ring network. The optical switching assembly monitors drop channels from the two rings of the network and attenuates the add channel(s) accordingly. An optical switch operates to direct the drop signal from one of the two rings to a receiver in accordance with a control signal based on the monitored drop channels. The self-adjusting optical add-drop multiplexer also monitors the power in the drop signals and issues an alarm if the drop signal is of a power level above or below predetermined levels.
    Type: Grant
    Filed: March 12, 2004
    Date of Patent: March 21, 2006
    Assignee: Avanex Corporation
    Inventors: Guohua Xiao, Xiaoping Mao, Lintao Zhang, Xiaofan Cao
  • Patent number: 6885821
    Abstract: The present invention provides an improved full-duplex optical communications system. The system includes: at least one office, where the at least one office provides a plurality of channels, the plurality of channels comprising a plurality of signal channels and a plurality of continuous wave (CW) channels; at least one optical add/drop multiplexer (OADM) optically coupled to the at least one office; and a subscriber premises optically coupled to the at least one OADM, where at least one of the plurality of signal channels and at least one of the plurality of CW channels are dropped from the plurality of channels to the subscriber premises by the at least one OADM, where the subscriber premises modulates the dropped at least one of the plurality of CW channels, where the modulated at least one of the plurality of CW channels is added to the plurality of channels by the at least one OADM.
    Type: Grant
    Filed: February 27, 2001
    Date of Patent: April 26, 2005
    Assignee: Avanex Corporation
    Inventors: Thomas F. Cooney, Simon Xiaofan Cao
  • Patent number: 6853487
    Abstract: An optical device includes: a first polarization beam splitter (PBS); a first set of optical rotators optically coupled to the first PBS; a second PBS optically coupled to the first set of optical rotators; a first reflection interferometer (RI) optically coupled to the second PBS; a second RI optically coupled to the first PBS; a second set of optical rotators optically coupled to the second PBS; a third PBS optically coupled to the second set of optical rotators; and a third RI optically coupled to the third PBS. Preferably, the optical device is an Optical Add/Drop Multiplexer and may further comprise an Input Port optically coupled to the first PBS, an Output Port optically coupled to the second PBS, and an Add Port optically coupled to the third PBS.
    Type: Grant
    Filed: February 11, 2002
    Date of Patent: February 8, 2005
    Assignee: Avanex Corporation
    Inventors: Shudong Wu, Simon Xiaofan Cao
  • Publication number: 20040175179
    Abstract: A self-adjusting optical add-drop multiplexer monitors the power in a drop signal and attenuates the power in an add signal to match the power in express WDM channels (signals). When used in a fiber network, and more particularly, in a metro network, the deleterious effects of optical amplification are reduced. Power attenuation is also used in an optical switching assembly particularly useful in two-fiber ring network. The optical switching assembly monitors drop channels from the two rings of the network and attenuates the add channel(s) accordingly. An optical switch operates to direct the drop signal from one of the two rings to a receiver in accordance with a control signal based on the monitored drop channels. The self-adjusting optical add-drop multiplexer also monitors the power in the drop signals and issues an alarm if the drop signal is of a power level above or below predetermined levels.
    Type: Application
    Filed: March 12, 2004
    Publication date: September 9, 2004
    Inventors: Guohua Xiao, Xiaoping Mao, Lintao Zhang, Xiaofan Cao
  • Patent number: 6786611
    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: September 24, 2002
    Date of Patent: September 7, 2004
    Assignee: Fujitsu Limited
    Inventors: Simon Xiaofan Cao, Masataka Shirasaki
  • Patent number: 6728440
    Abstract: The present invention provides the method and apparatus for multi-pass photonic processors with the use of circulators and multiple-fiber collimators. In one embodiment of the present invention, a circulator and a reflective element are placed at either end of a chain of cascaded processors. The circulator at a first end routes the light signal to be processed and passed from one processor to the next, the reflective element at a second end reflects the light to be reprocessed and passed from one processor to the previous, the light signal eventually reaches the circulator again and exits. In another embodiment of the present invention, multiple fiber strands are connected to the collimator of a photonic processor. Furthermore, all fiber strands are paired in order to reroute the light signals for reprocessing in the photonic processor.
    Type: Grant
    Filed: June 28, 2001
    Date of Patent: April 27, 2004
    Assignee: Avanex Corporation
    Inventors: Shudong Wu, Xiaofan Cao
  • Patent number: 6721509
    Abstract: A self-adjusting optical add-drop multiplexer monitors the power in a drop signal and attenuates the power in an add signal to match the power in express WDM channels (signals). When used in a fiber network, and more particularly, in a metro network, the deleterious effects of optical amplification are reduced. Power attenuation is also used in an optical switching assembly particularly useful in two-fiber ring network. The optical switching assembly monitors drop channels from the two rings of the network and attenuates the add channel(s) accordingly. An optical switch operates to direct the drop signal from one of the two rings to a receiver in accordance with a control signal based on the monitored drop channels. The self-adjusting optical add-drop multiplexer also monitors the power in the drop signals and issues an alarm if the drop signal is of a power level above or below predetermined levels.
    Type: Grant
    Filed: December 5, 2000
    Date of Patent: April 13, 2004
    Assignee: Avanex Corporation
    Inventors: Guohua Xiao, Xiaoping Mao, Lintao Zhang, Xiaofan Cao
  • Patent number: 6661953
    Abstract: An integrated multifunctional apparatus for fiber optic communication systems includes: at least one input fiber; a lens optically coupled to the at least one input fiber; a diffraction grating optically coupled to the lens at a side opposite to the at least one input fiber; at least one output fiber optically coupled to the lens at the side opposite to the diffraction grating; and a plurality of movable rods residing at the side of the lens opposite to the diffraction grating, where the plurality of movable rods is capable of intercepting a variable portion of a light traversing through the lens. The apparatus is capable of simultaneously performing the functions of multiplexing or de-multiplexing, variable optical attenuation and/or optical detection of plural channels comprising a wavelength division multiplexed composite optical signal.
    Type: Grant
    Filed: June 28, 2001
    Date of Patent: December 9, 2003
    Assignee: Avanex Corporation
    Inventor: Simon Xiaofan Cao
  • Patent number: 6553160
    Abstract: An asymmetric de-multiplexer/multiplexer includes: at least a first, second, and third optical fibers; at least one lens optically coupled to the first, second, and third optical fibers; at least one diffraction grating optically coupled to the at least one lens at a side opposite to the first, second, and third optical fibers; and a reflector array optically coupled to the at least one lens at a side opposite to the at least one diffraction grating. The reflector array includes: a substrate, and a plurality of reflectors coupled to the substrate at a side opposite to the at least one lens, where the plurality of reflectors reflects a first subset of channels of a composite optical signal traversing the apparatus, where the subset of channels has irregular inter-channel spacings and non-uniform bandwidths. The apparatus thus is able to overcome bandwidth utilization inefficiencies of conventional regular spaced channel assignment schemes.
    Type: Grant
    Filed: June 28, 2001
    Date of Patent: April 22, 2003
    Assignee: Avanex Corporation
    Inventor: Simon Xiaofan Cao
  • Patent number: 6525848
    Abstract: The present invention provides an improved switchable interleaved channel separator device. The switchable interleaved channel separator device utilizes a reflective interferometer and one single-segment switchable polarization rotator. The reflective interferometer causes signal light paths to be reflected back upon one another so as to realize an overall reduction in size. This path reflection also enables the capability of providing optical couplings predominantly or wholly at a single side or at adjacent sides of the device.
    Type: Grant
    Filed: February 23, 2001
    Date of Patent: February 25, 2003
    Assignee: Avanex Corporation
    Inventor: Simon Xiaofan Cao
  • 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: 20030002791
    Abstract: An integrated multifunctional apparatus for fiber optic communication systems includes: at least one input fiber; a lens optically coupled to the at least one input fiber; a diffraction grating optically coupled to the lens at a side opposite to the at least one input fiber; at least one output fiber optically coupled to the lens at the side opposite to the diffraction grating; and a plurality of movable rods residing at the side of the lens opposite to the diffraction grating, where the plurality of movable rods is capable of intercepting a variable portion of a light traversing through the lens. The apparatus is capable of simultaneously performing the functions of multiplexing or de-multiplexing, variable optical attenuation and/or optical detection of plural channels comprising a wavelength division multiplexed composite optical signal.
    Type: Application
    Filed: June 28, 2001
    Publication date: January 2, 2003
    Inventor: Simon Xiaofan Cao
  • Publication number: 20030002785
    Abstract: An asymmetric de-multiplexer/multiplexer includes: at least a first, second, and third optical fibers; at least one lens optically coupled to the first, second, and third optical fibers; at least one diffraction grating optically coupled to the at least one lens at a side opposite to the first, second, and third optical fibers; and a reflector array optically coupled to the at least one lens at a side opposite to the at least one diffraction grating. The reflector array includes: a substrate, and a plurality of reflectors coupled to the substrate at a side opposite to the at least one lens, where the plurality of reflectors reflects a first subset of channels of a composite optical signal traversing the apparatus, where the subset of channels has irregular inter-channel spacings and non-uniform bandwidths. The apparatus thus is able to overcome bandwidth utilization inefficiencies of conventional regular spaced channel assignment schemes.
    Type: Application
    Filed: June 28, 2001
    Publication date: January 2, 2003
    Inventor: Simon Xiaofan Cao
  • Patent number: 6490386
    Abstract: A bi-directional amplifier system comprises a 2×2 interleaved channel separator optically coupled to both a first and a second bi-directional fiber optic communications line and an optical amplifier optically coupled to the 2×2 interleaved channel separator.
    Type: Grant
    Filed: January 31, 2001
    Date of Patent: December 3, 2002
    Inventors: Xiaofan Cao, Thomas F. Cooney
  • 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
  • Publication number: 20020118434
    Abstract: The present invention provides an improved switchable interleaved channel separator device. The switchable interleaved channel separator device utilizes a reflective interferometer and one single-segment switchable polarization rotator. The reflective interferometer causes signal light paths to be reflected back upon one another so as to realize an overall reduction in size. This path reflection also enables the capability of providing optical couplings predominantly or wholly at a single side or at adjacent sides of the device.
    Type: Application
    Filed: February 23, 2001
    Publication date: August 29, 2002
    Inventor: Simon Xiaofan Cao
  • Publication number: 20020118411
    Abstract: The present invention provides an improved full-duplex optical communications system. The system includes: at least one office, where the at least one office provides a plurality of channels, the plurality of channels comprising a plurality of signal channels and a plurality of continuous wave (CW) channels; at least one optical add/drop multiplexer (OADM) optically coupled to the at least one office; and a subscriber premises optically coupled to the at least one OADM, where at least one of the plurality of signal channels and at least one of the plurality of CW channels are dropped from the plurality of channels to the subscriber premises by the at least one OADM, where the subscriber premises modulates the dropped at least one of the plurality of CW channels, where the modulated at least one of the plurality of CW channels is added to the plurality of channels by the at least one OADM.
    Type: Application
    Filed: February 27, 2001
    Publication date: August 29, 2002
    Inventors: Thomas F. Cooney, Simon Xiaofan Cao
  • Patent number: 6441952
    Abstract: The present invention provides a hybrid Raman/EDFA optical amplifier that utilizes a first optical detector that generates a first electrical or electronic signal that is proportional the combined optical power of the signal light and the leaked pump laser light, a second optical detector that generates a second electrical or electronic signal that is proportional to the power of the pump laser light and an electronic subtraction circuit that receives the first and second electrical or electronic signals and generates a difference signal that is proportional to only to the optical power of the signal light and insensitive to the power of the Raman pump laser light. The difference signal is utilized by an EDFA control circuit to control and/or adjust the operation of the EDFA based upon changes in the power of the input optical signal.
    Type: Grant
    Filed: July 3, 2001
    Date of Patent: August 27, 2002
    Assignee: Avanex Corporation
    Inventors: Xiaodong Duan, Guohua Xiao, Lintao Zhang, Dongqi Liu, Gang Li, Paul Hull, Charles Xiaoping Mao, Simon Xiaofan Cao
  • Publication number: 20020101636
    Abstract: A self-adjusting optical add-drop multiplexer monitors the power in a drop signal and attenuates the power in an add signal to match the power in express WDM channels (signals). When used in a fiber network, and more particularly, in a metro network, the deleterious effects of optical amplification are reduced. Power attenuation is also used in an optical switching assembly particularly useful in two-fiber ring network. The optical switching assembly monitors drop channels from the two rings of the network and attenuates the add channel(s) accordingly. An optical switch operates to direct the drop signal from one of the two rings to a receiver in accordance with a control signal based on the monitored drop channels. The self-adjusting optical add-drop multiplexer also monitors the power in the drop signals and issues an alarm if the drop signal is of a power level above or below predetermined levels.
    Type: Application
    Filed: December 5, 2000
    Publication date: August 1, 2002
    Inventors: Guohua Xiao, Xiaoping Mao, Lintao Zhang, Xiaofan Cao