Patents by Inventor Thomas Huntington Wood

Thomas Huntington Wood 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: 9960846
    Abstract: A free-space optical communication system is provided. The free-space optical communication system includes a transmitter configured to optically transmit data in a plurality of subcarrier signals over a free-space scattering medium. The free-space optical communication system includes a coherent receiver configured to receive the plurality of subcarrier signals and extract the transmitted data from the plurality of subcarrier signals after traversal over the free-space scattering medium.
    Type: Grant
    Filed: July 14, 2016
    Date of Patent: May 1, 2018
    Assignee: LGS INNOVATIONS LLC
    Inventors: Thomas Huntington Wood, Stephan Frank Wielandy, Andrew Russell Grant
  • Publication number: 20170237485
    Abstract: A free-space optical communication system is provided. The free-space optical communication system includes a transmitter configured to optically transmit data in a plurality of subcarrier signals over a free-space scattering medium. The free-space optical communication system includes a coherent receiver configured to receive the plurality of subcarrier signals and extract the transmitted data from the plurality of subcarrier signals after traversal over the free-space scattering medium.
    Type: Application
    Filed: July 14, 2016
    Publication date: August 17, 2017
    Inventors: Thomas Huntington Wood, Stephan Frank Wielandy, Andrew Russell Grant
  • Patent number: 8744275
    Abstract: An apparatus transmits data using a format where information bits intended for transmission are mapped into symbols each carrying a plurality of bits, some of which are encoded through pulse position modulation (PPM) format and the rest of which are encoded through an additional modulation format on each PPM pulse. The additional modulation format for the PPM pulse may be at least one of a polarization-division-multiplexed (PDM) modulation, phase-shift keying (PSK) modulation, polarization shift keying (PolSK) modulation, amplitude modulation (AM), quadrature-amplitude modulation (QAM) modulation, or a combination thereof. In one embodiment, the additional modulation of the PPM pulses is through polarization-division-multiplexed quadrature-phase-shift keying (PDM-QPSK). The unique combined use of PDM-QPSK and PPM produces much higher receiver sensitivity than either PPM or PDM-QPSK alone.
    Type: Grant
    Filed: March 5, 2011
    Date of Patent: June 3, 2014
    Assignee: LGS Innovations LLC
    Inventors: Xiang Liu, Thomas Huntington Wood, Robert William Tkach
  • Patent number: 8682181
    Abstract: An apparatus receives data encoded in a format where information bits for transmission are mapped into symbols each carrying a plurality of bits, some being encoded through a pulse position modulation (PPM) format and some being encoded through an additional modulation format on at least one PPM pulse. A receiver detects the signal through a dual-polarization coherent receiver front-end, recovering polarization components of the signal by decoding a first non-zero portion of a plurality of bits carried by a symbol based on slot position of at least one PPM pulse in the polarization components and a second non-zero portion of the plurality of bits carried by the symbol based on the additional modulation carried by at least one PPM pulse in the polarization components. Pilot-assisted single-carrier frequency-division equalization (PA-SC-FDE) may be used for reliable signal reception in the presence of severe PPM errors.
    Type: Grant
    Filed: March 5, 2011
    Date of Patent: March 25, 2014
    Assignees: Alcatel Lucent, LGS Innovations LLC
    Inventors: Xiang Liu, Thomas Huntington Wood, Robert William Tkach
  • Patent number: 8320039
    Abstract: An optical amplifier comprises at least two gain regions, an intermediate region situated between the gain regions, and a transition region situated between the intermediate region and each gain region. The aforesaid regions have claddings that collectively form a path for pump radiation propagating from at least one of the gain regions to the other gain region, and cores that collectively form a path for signal radiation propagating from at least one of the gain regions to the other gain region. The cores in the gain regions support multiple propagating optical modes, including at least one signal mode and at least one non-signal mode. The intermediate region, however, supports fewer propagating core modes than are supported by the gain regions. The transition regions are conformed such that when radiation in propagating non-signal core modes passes from the gain regions into the intermediate region, it is at least partly coupled into cladding modes of the intermediate region.
    Type: Grant
    Filed: April 16, 2010
    Date of Patent: November 27, 2012
    Assignee: LGS Innovations LLC
    Inventors: Douglas P. Holcomb, Thomas Huntington Wood, Paul Wysocki
  • Publication number: 20120224852
    Abstract: An apparatus transmits data using a format where information bits intended for transmission are mapped into symbols each carrying a plurality of bits, some of which are encoded through pulse position modulation (PPM) format and the rest of which are encoded through an additional modulation format on each PPM pulse. The additional modulation format for the PPM pulse may be at least one of a polarization-division-multiplexed (PDM) modulation, phase-shift keying (PSK) modulation, polarization shift keying (PolSK) modulation, amplitude modulation (AM), quadrature-amplitude modulation (QAM) modulation, or a combination thereof. In one embodiment, the additional modulation of the PPM pulses is through polarization-division-multiplexed quadrature-phase-shift keying (PDM-QPSK). The unique combined use of PDM-QPSK and PPM produces much higher receiver sensitivity than either PPM or PDM-QPSK alone.
    Type: Application
    Filed: March 5, 2011
    Publication date: September 6, 2012
    Inventors: Xiang Liu, Thomas Huntington Wood, Robert William Tkach
  • Publication number: 20120224862
    Abstract: An apparatus receives data encoded in a format where information bits for transmission are mapped into symbols each carrying a plurality of bits, some of which are encoded through a pulse position modulation (PPM) format and the rest of which are encoded through an additional modulation format on at least one PPM pulse. The receiver detects the signal through a dual-polarization coherent receiver front-end, and recovers polarization components of the signal by decoding a first non-zero portion of a plurality of bits carried by a symbol based on slot position of at least one PPM pulse in the polarization components and a second non-zero portion of the plurality of bits carried by the symbol based on the additional modulation carried by at least one PPM pulse in the polarization components. Pilot-assisted single-carrier frequency-division equalization (PA-SC-FDE) may be used for reliable signal reception in the presence of severe PPM errors.
    Type: Application
    Filed: March 5, 2011
    Publication date: September 6, 2012
    Inventors: Xiang Liu, Thomas Huntington Wood, Robert William Tkach
  • Publication number: 20110255153
    Abstract: An optical amplifier comprises at least two gain regions, an intermediate region situated between the gain regions, and a transition region situated between the intermediate region and each gain region. The aforesaid regions have claddings that collectively form a path for pump radiation propagating from at least one of the gain regions to the other gain region, and cores that collectively form a path for signal radiation propagating from at least one of the gain regions to the other gain region. The cores in the gain regions support multiple propagating optical modes, including at least one signal mode and at least one non-signal mode. The intermediate region, however, supports fewer propagating core modes than are supported by the gain regions. The transition regions are conformed such that when radiation in propagating non-signal core modes passes from the gain regions into the intermediate region, it is at least partly coupled into cladding modes of the intermediate region.
    Type: Application
    Filed: April 16, 2010
    Publication date: October 20, 2011
    Inventors: Douglas P. Holcomb, Thomas Huntington Wood, Paul Wysocki
  • Patent number: 7088921
    Abstract: A data communications system which provides multiple logical channels on a passive optical network (PON) using subcarrier multiple access (SCMA). The PON includes multiple optical network units (ONU) which each communicate with a head-end over a logical channel. Collisions among upstream transmissions are thereby avoided and high speed Ethernet service over large distances is made possible.
    Type: Grant
    Filed: June 11, 1999
    Date of Patent: August 8, 2006
    Assignee: Lucent Technologies Inc.
    Inventor: Thomas Huntington Wood
  • Patent number: 6671465
    Abstract: The linearity and noise performance of an inexpensive optical signal source are improved using either feedback or feedforward correction techniques. In a feedback embodiment of the invention, a modulation signal, such as a broadband analog CATV signal, is applied to the optical source along with an error signal. The error signal is generated in a feedback path using a high-speed photodiode to detect a portion of the output optical signal generated by the optical source. A delay compensation filter in the feedback path corrects for variations in error signal delay as a function of frequency, such that source nonlinearity and noise may be corrected over a broad bandwidth. In a feedforward embodiment of the invention, an error signal generated from a portion of the output of the optical source is converted to a frequency band outside of the modulation signal bandwidth before being applied to an input of the optical source.
    Type: Grant
    Filed: April 7, 2000
    Date of Patent: December 30, 2003
    Assignee: Lucent Technologies Inc.
    Inventors: Yacov Cohen, Thomas Huntington Wood
  • Patent number: 6151145
    Abstract: A two-wavelength WDM analog CATV transmission system which utilizes wavelength channel spacing of about 2.2 nm and laser-dithering. The system includes a pair of optical transmitters (DBF lasers), a pair of modulators, a dithering device, a polarization controller, a 3-dB combiner, an optical amplifier (EDFA), an attenuator, a length of optical fiber, a filter and a CATV receiver. The two lasers have wavelengths of .lambda.1 and .lambda.2, where the difference between .lambda.1 and .lambda.2 is approximately 2.2 nm. The modulators are driven with analog signals comprising 77 NTSC channels between 55.25 and 535.25 MHz A 2-GHz dithering tone is applied to the .lambda.1 laser and the output of the .lambda.2 laser is passed through the polarization controller to align the polarization of the two transmitters.
    Type: Grant
    Filed: January 22, 1998
    Date of Patent: November 21, 2000
    Assignee: Lucent Technologies Inc.
    Inventors: Atul Kumar Srivastava, Thomas Huntington Wood, John Lehrer Zyskind
  • Patent number: 6137607
    Abstract: A method and apparatus for substantially reducing OBI on optical networks in which a number of source lasers operate simultaneously and the output from the lasers is subsequently combined in the network. The method involves operating the laser in burst mode such that the laser is operational only during transmission periods.
    Type: Grant
    Filed: February 23, 1998
    Date of Patent: October 24, 2000
    Assignee: Lucent Technologies Inc.
    Inventors: Robert D. Feldman, Gordon Cook Wilson, Thomas Huntington Wood
  • Patent number: 6072616
    Abstract: The linearity and noise performance of an inexpensive optical signal source are improved using either feedback or feedforward correction techniques. In a feedback embodiment of the invention, a modulation signal, such as a broadband analog CATV signal, is applied to the optical source along with an error signal. The error signal is generated in a feedback path using a high-speed photodiode to detect a portion of the output optical signal generated by the optical source. A delay compensation filter in the feedback path corrects for variations in error signal delay as a function of frequency, such that source nonlinearity and noise may be corrected over a broad bandwidth. In a feedforward embodiment of the invention, an error signal generated from a portion of the output of the optical source is converted to a frequency band outside of the modulation signal bandwidth before being applied to an input of the optical source.
    Type: Grant
    Filed: June 23, 1997
    Date of Patent: June 6, 2000
    Assignee: Lucent Technologies Inc.
    Inventors: Yacov Cohen, Thomas Huntington Wood
  • Patent number: 5963684
    Abstract: An optical demultiplexing apparatus is capable of spatially separating a multiplexed optical signal into two or more optical wavelength signals thereof. An input multiplexed optical signal present on a first plane is imaged through a color-selective grating plane to a second plane. The color-selective grating has a nonlinear change of diffraction characteristics as a function of incident wavelength to provide substantial spatial separation in the second plane between bands of wavelengths proximate to the two or more optical wavelength signals. In another embodiment, the apparatus uses a polarization-selective grating to spatially separate a polarization-multiplexed optical signal into two substantial spatially separated optical polarization signals. In other embodiments, the optical apparatus may be used as an optical signal multiplexer, splitter, or combiner.
    Type: Grant
    Filed: February 13, 1997
    Date of Patent: October 5, 1999
    Assignee: Lucent Technologies Inc.
    Inventors: Joseph Earl Ford, Thomas Huntington Wood, James Albert Walker