Patents by Inventor David F. Welch

David F. Welch 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: 20210091856
    Abstract: A network or system in which a hub or primary node may communicate with a plurality of leaf or secondary nodes. The hub node may operate or have a capacity greater than that of the leaf nodes. Accordingly, relatively inexpensive leaf nodes may be deployed to receive data carrying optical signals from, and supply data carrying optical signals to, the hub node. One or more connections may couple each leaf node to the hub node, whereby each connection may include one or more spans or segments of optical fibers, optical amplifiers, optical splitters/combiners, and optical add/drop multiplexer, for example. Optical subcarriers may be transmitted over such connections, each carrying a data stream. The subcarriers may be generated by a combination of a laser and a modulator, such that multiple lasers and modulators are not required, and costs may be reduced.
    Type: Application
    Filed: September 22, 2019
    Publication date: March 25, 2021
    Inventors: Jeffrey T. Rahn, Kuang-Tsan Wu, Steven J. Hand, David F. Welch
  • Publication number: 20200413169
    Abstract: A network or system in which a hub or primary node may communicate with a plurality of leaf or secondary nodes. The hub node may operate or have a capacity greater than that of the leaf nodes. Accordingly, relatively inexpensive leaf nodes may be deployed to receive data carrying optical signals from, and supply data carrying optical signals to, the hub node. One or more connections may couple each leaf node to the hub node, whereby each connection may include one or more spans or segments of optical fibers, optical amplifiers, optical splitters/combiners, and optical add/drop multiplexer, for example. Optical subcarriers may be transmitted over such connections, each carrying a data stream. The subcarriers may be generated by a combination of a laser and a modulator, such that multiple lasers and modulators are not required, and costs may be reduced.
    Type: Application
    Filed: September 22, 2019
    Publication date: December 31, 2020
    Inventors: Jeffrey T. Rahn, Kuang-Tsan Wu, Steven J. Hand, David F. Welch
  • Publication number: 20200403702
    Abstract: A network or system in which a hub or primary node may communicate with a plurality of leaf or secondary nodes. The hub node may operate or have a capacity greater than that of the leaf nodes. Accordingly, relatively inexpensive leaf nodes may be deployed to receive data carrying optical signals from, and supply data carrying optical signals to, the hub node. One or more connections may couple each leaf node to the hub node, whereby each connection may include one or more spans or segments of optical fibers, optical amplifiers, optical splitters/combiners, and optical add/drop multiplexer, for example. Optical subcarriers may be transmitted over such connections, each carrying a data stream. The subcarriers may be generated by a combination of a laser and a modulator, such that multiple lasers and modulators are not required, and costs may be reduced.
    Type: Application
    Filed: September 22, 2019
    Publication date: December 24, 2020
    Inventors: Jeffrey T. Rahn, Kuang-Tsan Wu, Steven J. Hand, David F. Welch
  • Publication number: 20200403704
    Abstract: A network or system in which a hub or primary node may communicate with a plurality of leaf or secondary nodes. The hub node may operate or have a capacity greater than that of the leaf nodes. Accordingly, relatively inexpensive leaf nodes may be deployed to receive data carrying optical signals from, and supply data carrying optical signals to, the hub node. One or more connections may couple each leaf node to the hub node, whereby each connection may include one or more spans or segments of optical fibers, optical amplifiers, optical splitters/combiners, and optical add/drop multiplexer, for example. Optical subcarriers may be transmitted over such connections, each carrying a data stream. The subcarriers may be generated by a combination of a laser and a modulator, such that multiple lasers and modulators are not required, and costs may be reduced.
    Type: Application
    Filed: September 22, 2019
    Publication date: December 24, 2020
    Inventors: Jeffrey T. Rahn, Kuang-Tsan Wu, Steven J. HAND, David F. Welch
  • Publication number: 20200382216
    Abstract: A network or system in which a hub or primary node may communicate with a plurality of leaf or secondary nodes. The hub node may operate or have a capacity greater than that of the leaf nodes. Accordingly, relatively inexpensive leaf nodes may be deployed to receive data carrying optical signals from, and supply data carrying optical signals to, the hub node. One or more connections may couple each leaf node to the hub node, whereby each connection may include one or more spans or segments of optical fibers, optical amplifiers, optical splitters/combiners, and optical add/drop multiplexer, for example. Optical subcarriers may be transmitted over such connections, each carrying a data stream. The subcarriers may be generated by a combination of a laser and a modulator, such that multiple lasers and modulators are not required, and costs may be reduced.
    Type: Application
    Filed: September 23, 2019
    Publication date: December 3, 2020
    Inventors: Jeffrey T. Rahn, Kuang-Tsan Wu, Steven J. Hand, David F. Welch
  • Publication number: 20200287621
    Abstract: A transmitter can include a laser operable to output an optical signal; a digital signal processor operable to receive user data and provide electrical signals based on the data; and a modulator operable to modulate the optical signal to provide optical subcarriers based on the electrical signals. A first one of the subcarriers carriers carries first TDMA encoded information and second TDMA encoded information, such that the first TDMA encoded information is indicative of a first portion of the data and is carried by the first one of the subcarriers during a first time slot, and the second TDMA encoded information is indicative of a second portion of the data and is carried by the first one of the subcarriers during a second time slot. The first TDMA encoded information is associated with a first node remote from the transmitter and the second TDMA encoded information is associated with a second node remote from the transmitter.
    Type: Application
    Filed: March 4, 2020
    Publication date: September 10, 2020
    Inventors: Amir Jafari, Kuang-Tsan Wu, David F. Welch, Steven Joseph Hand, Mohamed Osman
  • Publication number: 20200287651
    Abstract: A transmitter can include a laser operable to output an optical signal; a digital signal processor operable to receive data and provide a plurality of electrical signals based on the data; and a modulator operable to modulate the optical signal to provide a plurality of optical subcarriers based on the plurality of electrical signals. One of the plurality of subcarriers carries first information indicative of a first portion of the data in a first time slot and second information indicative of a second portion of the data in a second time slot. The first information is associated with a first node remote from the transmitter and the second information is associated with a second node remote from the transmitter. A receiver as well as a system also are described.
    Type: Application
    Filed: March 4, 2020
    Publication date: September 10, 2020
    Inventors: Amir Jafari, Kuang-Tsan Wu, David F. Welch, Steven Joseph Hand, Mohamed Osman
  • Publication number: 20200287649
    Abstract: Consistent the present disclosure, a network or system is provided in which a hub or primary node may communication with a plurality of leaf or secondary nodes. The hub node may operate or have a capacity that may be greater than that of the leaf nodes. Accordingly, relatively inexpensive leaf nodes may be deployed that receive data carrying optical signals from and supply data carrying optical signals to the hub node. One or more connections may couple each leaf node to the hub node, whereby each connection may include one or more spans or segments of optical fibers, optical amplifiers, and optical add/drop multiplexer, for example. Consistent with an aspect of the present disclosure, optical subcarriers may be transmitted over such connections. The subcarriers may be generated by a combination of a laser and a modulator, such that multiple lasers and modulators are not required, and costs may be reduced.
    Type: Application
    Filed: March 4, 2020
    Publication date: September 10, 2020
    Inventors: Amir Jafari, David F. Welch, Steven Joseph Hand, Mohamed Osman
  • Publication number: 20200287648
    Abstract: Consistent the present disclosure, a network or system is provided in which a hub or primary node may communication with a plurality of leaf or secondary nodes. The hub node may operate or have a capacity that may be greater than that of the leaf nodes. Accordingly, relatively inexpensive leaf nodes may be deployed that receive data carrying optical signals from and supply data carrying optical signals to the hub node. One or more connections may couple each leaf node to the hub node, whereby each connection may include one or more spans or segments of optical fibers, optical amplifiers, and optical add/drop multiplexer, for example. Consistent with an aspect of the present disclosure, optical subcarriers may be transmitted over such connections. The subcarriers may be generated by a combination of a laser and a modulator, such that multiple lasers and modulators are not required, and costs may be reduced.
    Type: Application
    Filed: March 4, 2020
    Publication date: September 10, 2020
    Inventors: Amir Jafari, David F. Welch, Steven Joseph Hand, Mohamed Osman
  • Publication number: 20200252154
    Abstract: Methods, systems, and apparatus for subcarrier modulation with radio frequency inphase-quadrature (IQ) modulators. A system includes a plurality of IQ modulators, each configured to receive an input electrical signal comprising an inphase signal and a quadrature signal, and each configured to modulate the inphase signal and quadrature signal based on one of a plurality of local oscillator signals to output a multiplexed signal. Each of the plurality of local oscillator signals is supplied by a respective one of a plurality of local oscillator circuits. A modulator circuit is configured to modulate a carrier optical signal from a laser having a frequency ?c based on the multiplexed signal to generate a modulated optical signal centered at frequency ?c and comprising a plurality of subcarriers. A center frequency of each of the plurality of subcarriers is offset from ?c by a frequency of said one of the plurality of local oscillator signals.
    Type: Application
    Filed: December 30, 2019
    Publication date: August 6, 2020
    Inventors: Kuang-Tsan Wu, Han Sun, Steven J. Hand, David F. Welch
  • Patent number: 10012797
    Abstract: A semiconductor monolithic transmitter photonic integrated circuit (TxPIC) comprises two different situations, either at least one signal channel in the PIC having a modulated source with the channel also extended to include at least one additional element or a plurality of modulated sources comprising N signal channels in the PIC of different transmission wavelengths, where N is equal to or greater than two (2), which may also approximate emission wavelengths along a standardized wavelength grid. In these two different situations, a common active region for such modulated sources and additional channel elements is identified as an extended identical active layer (EIAL), as it extends from a single modulated source to such additional channel elements in the same channel and/or extends to additional modulated sources in separate channels where the number of such channels is N equal to two or greater.
    Type: Grant
    Filed: January 27, 2005
    Date of Patent: July 3, 2018
    Assignee: Infinera Corporation
    Inventors: Radhakrishnan L. Nagarajan, Fred A. Kish, Jr., Masaki Kato, Charles H. Joyner, David F. Welch, Randal A. Salvatore, Richard P. Schneider, Mehrdad Ziari, Damien Jean Henri Lambert, Sheila K. Hurtt, Andrew G. Dentai, Atul Mathur, Vincent G. Dominic
  • Patent number: 9971090
    Abstract: A laser source or a plurality of laser sources in a photonic integrated circuit (PIC) are provided with an electrical contact that is either segmented or is connected to a series of vernier resistor segments for supply of current to operate the laser source. In either case, at least one segment of the laser contact or at least one vernier resistor segment can be trimmed in order to vary the amount of current supplied to the laser source resulting in a change to its current density and, thus, a change in its operational wavelength while maintaining the current supplied to the laser source constant.
    Type: Grant
    Filed: August 11, 2004
    Date of Patent: May 15, 2018
    Assignee: Infinera Corporation
    Inventors: Fred A. Kish, Jr., Charles H. Joyner, David F. Welch
  • Patent number: 9634788
    Abstract: Consistent with the present disclosure, an optical communication system is provided in which client data is input to a first node and output from a second node, spaced from the first node, with little delay. In one example, the delay is reduced by including higher order Raman amplifiers that provide a substantially uniform gain along the length of a fiber optic link, thereby reducing the number of EDFAs that may otherwise be installed along the optical fiber link or eliminating such EDFAs entirely. In another example, FEC encoding and decoding are not employed, thereby reducing the delay even further.
    Type: Grant
    Filed: September 3, 2010
    Date of Patent: April 25, 2017
    Assignee: Infinera Corporation
    Inventors: Paul R. Morkel, David F. Welch
  • Patent number: 9372306
    Abstract: A method provides acceptable performance from a semiconductor transmitter photonic integrated circuit (TxPIC) that contains a plurality of modulated sources each comprising a laser source and an external modulator where each laser source provides a different emission wavelength and each modulated source forms a separate signal channel, comprising the steps of providing at least some of the signal channels with an extended identical active layer (EIAL) so that the modulated sources each have an identical active region wavelength and detuning the laser emission wavelength in each laser source within the EIAL from the laser active region wavelength.
    Type: Grant
    Filed: January 27, 2005
    Date of Patent: June 21, 2016
    Assignee: Infinera Corporation
    Inventors: Radhakrishnan L. Nagarajan, Fred A. Kish, Jr., Masaki Kato, Charles H. Joyner, David F. Welch, Randal A. Salvatore, Richard P. Schneider, Mehrdad Ziari, Damien Jean Henri Lambert, Sheila K. Hurtt, Andrew G. Dentai, Atul Mathur, Vincent G. Dominic
  • Patent number: 9166696
    Abstract: An apparatus including a photodiode, a low pass filter, an analog-to-digital converter, an interpolation circuit and a digital signal processor is disclosed. The photodiode receives a portion of a plurality of optical signals, each of which is modulated in accordance with a corresponding one of a plurality of data streams, and each having a corresponding one of a plurality of wavelengths. The photodiode supplies an electrical output. The low-pass filter supplies a filtered output in response to the electrical output. The analog-to-digital converter is configured to sample the filtered output at a first sampling rate to generate a plurality of first data samples. The interpolation circuit is configured to receive the plurality of first data samples and supply a plurality of second data samples at a second sampling rate less the first sampling rate. The digital signal processor circuit is configured to receive the plurality of second data samples.
    Type: Grant
    Filed: August 28, 2014
    Date of Patent: October 20, 2015
    Assignee: Infinera Corporation
    Inventors: Kuang-Tsan Wu, John D. McNicol, David F. Welch, Stephen G. Grubb, Pierre Mertz
  • Patent number: 9031412
    Abstract: A coolerless photonic integrated circuit (PIC), such as a semiconductor electro-absorption modulator/laser (EML) or a coolerless optical transmitter photonic integrated circuit (TxPIC), may be operated over a wide temperature range at temperatures higher then room temperature without the need for ambient cooling or hermetic packaging. Since there is large scale integration of N optical transmission signal WDM channels on a TxPIC chip, a new DWDM system approach with novel sensing schemes and adaptive algorithms provides intelligent control of the PIC to optimize its performance and to allow optical transmitter and receiver modules in DWDM systems to operate uncooled. Moreover, the wavelength grid of the on-chip channel laser sources may thermally float within a WDM wavelength band where the individual emission wavelengths of the laser sources are not fixed to wavelength peaks along a standardized wavelength grid but rather may move about with changes in ambient temperature.
    Type: Grant
    Filed: November 4, 2009
    Date of Patent: May 12, 2015
    Assignee: Infinera Corporation
    Inventors: Radhakrishnan L. Nagarajan, Fred A. Kish, Jr., David F. Welch, Drew D. Perkins, Masaki Kato
  • Publication number: 20140369698
    Abstract: An apparatus including a photodiode, a low pass filter, an analog-to-digital converter, an interpolation circuit and a digital signal processor is disclosed. The photodiode receives a portion of a plurality of optical signals, each of which is modulated in accordance with a corresponding one of a plurality of data streams, and each having a corresponding one of a plurality of wavelengths. The photodiode supplies an electrical output. The low-pass filter supplies a filtered output in response to the electrical output. The analog-to-digital converter is configured to sample the filtered output at a first sampling rate to generate a plurality of first data samples. The interpolation circuit is configured to receive the plurality of first data samples and supply a plurality of second data samples at a second sampling rate less the first sampling rate. The digital signal processor circuit is configured to receive the plurality of second data samples.
    Type: Application
    Filed: August 28, 2014
    Publication date: December 18, 2014
    Inventors: Kuang-Tsan Wu, John D. McNicol, David F. Welch, Stephen G. Grubb, Pierre Mertz
  • Patent number: 8861977
    Abstract: A number of carriers are selected according to a modulation format and symbol rate to realize a superchannel having fixed capacity, for example. At a receive node, the superchannel is optically demultiplexed from a plurality of other superchannels. The plurality of carriers are then supplied to a photodetector circuit, which receives additional light at one of the optical signal carrier wavelengths from a local oscillator laser. An analog-to-digital converter (ADC) is provided in the receive node to convert the electrical signals output from the photodetector into digital form. The output from the ADC is then filtered in the electrical domain, such that optical demultiplexing of the carriers is unnecessary.
    Type: Grant
    Filed: April 1, 2011
    Date of Patent: October 14, 2014
    Assignee: Infinera Corporation
    Inventors: John D. McNicol, Matthew L. Mitchell, David F. Welch
  • Patent number: 8831439
    Abstract: Consistent with the present disclosure, data, in digital form, is received by a transmit nodes of an optical communication, and converted to analog signal by a digital-to-analog converter (DAC) to drive a modulator. The modulator, in turn, modulates light at one of a plurality of wavelengths in accordance with the received data. The modulated light is then transmitted over an optical communication path to a receive node. At the receive node, the modulated optical signal, as well as other modulated optical signals are supplied to a photodetector circuit, which receives additional light at one of the optical signal wavelengths from a local oscillator laser. An analog-to-digital converter (ADC) is provided in the receive node to convert the electrical signals output from the photodetector into digital form. The output from the ADC is then filtered in the electrical domain, such that optical demultiplexing of individual channels is unnecessary.
    Type: Grant
    Filed: October 5, 2010
    Date of Patent: September 9, 2014
    Assignee: Infinera Corporation
    Inventors: Kuang-Tsan Wu, John D. McNicol, David F. Welch, Stephen G. Grubb, Pierre Mertz
  • Patent number: 8768177
    Abstract: Consistent with the present disclosure, data, in digital form, is received by a transmit nodes of an optical communication, and converted to analog signal by a digital-to-analog converter (DAC) to drive a modulator. The modulator, in turn, modulates light at one of a plurality of wavelengths in accordance with the received data. The modulated light is then transmitted over an optical communication path to a receive node. At the receive node, the modulated optical signal, as well as other modulated optical signals are supplied to a photodetector circuit, which receives additional light at one of the optical signal wavelengths from a local oscillator laser. An analog-to-digital converter (ADC) is provided in the receive node to convert the electrical signals output from the photodetector into digital form. The output from the ADC is then filtered in the electrical domain, such that optical demultiplexing of individual channels is unnecessary.
    Type: Grant
    Filed: October 5, 2010
    Date of Patent: July 1, 2014
    Assignee: Infinera Corporation
    Inventors: Kuang-Tsan Wu, John D. McNicol, David F. Welch, Stephen G. Grubb, Pierre Mertz