Patents by Inventor Radhakrishnan L. Nagarajan

Radhakrishnan L. Nagarajan 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: 10469176
    Abstract: The present invention is directed to communication systems and methods. In a specific embodiment, the present invention provides an optical receiver that receives a data stream from an optical transmitter. The optical receiver determines a histogram contour parameter using the data stream and inserts the histogram contour parameter into a back-channel data segment, which is then transmitted to the optical transmitter. The optical transmitter changes its data transmission setting based on the histogram contour parameter. There are other embodiments as well.
    Type: Grant
    Filed: July 7, 2017
    Date of Patent: November 5, 2019
    Assignee: INPHI CORPORATION
    Inventors: Todd Rope, Hari Shankar, Radhakrishnan L. Nagarajan
  • Publication number: 20190319703
    Abstract: The present invention is directed to communication systems and methods. According to an embodiment, a receiving optical transceiver determines signal quality for signals received from a transmitting optical transceiver. Information related to the signal quality is embedded into back-channel data and sent to the transmitting optical transceiver. The transmitting optical transceiver detects the presence of the back-channel data and adjusts one or more of its operating parameters based on the back-channel data. There are other embodiments as well.
    Type: Application
    Filed: June 21, 2019
    Publication date: October 17, 2019
    Inventors: Todd ROPE, Radhakrishnan L. NAGARAJAN
  • Patent number: 10425164
    Abstract: The present invention relates to telecommunication techniques and integrated circuit (IC) devices. More specifically, embodiments of the present invention provide an off-quadrature modulation system. Once an off-quadrature modulation position is determined, a ratio between DC power transfer amplitude and dither tone amplitude for a modulator is as a control loop target to stabilize off-quadrature modulation. DC power transfer amplitude is obtained by measuring and sampling the output of an optical modulator. Dither tone amplitude is obtained by measuring and sampling the modulator output and performing calculation using the optical modulator output values and corresponding dither tone values. There are other embodiments as well.
    Type: Grant
    Filed: September 28, 2018
    Date of Patent: September 24, 2019
    Assignee: INPHI CORPORATION
    Inventors: Todd Rope, Radhakrishnan L. Nagarajan, Hari Shankar
  • Publication number: 20190288786
    Abstract: An integrated apparatus with optical/electrical interfaces and protocol converter on a single silicon substrate. The apparatus includes an optical module comprising one or more modulators respectively coupled with one or more laser devices for producing a first optical signal to an optical interface and one or more photodetectors for detecting a second optical signal from the optical interface to generate a current signal. Additionally, the apparatus includes a transmit lane module coupled between the optical module and an electrical interface to receive a first electric signal from the electrical interface and provide a framing protocol for driving the one or more modulators. Furthermore, the apparatus includes a receive lane module coupled between the optical module and the electrical interface to process the current signal to send a second electric signal to the electrical interface.
    Type: Application
    Filed: June 4, 2019
    Publication date: September 19, 2019
    Inventor: Radhakrishnan L. NAGARAJAN
  • Patent number: 10417176
    Abstract: The present invention provides an integrated system-on-chip device. The device is configured on a single silicon substrate member. The device has a data input/output interface provided on the substrate member. The device has an input/output block provided on the substrate member and coupled to the data input/output interface. The device has a signal processing block provided on the substrate member and coupled to the input/output block. The device has a driver module provided on the substrate member and coupled to the signal processing block. The device further includes a driver interface and coupled to the driver module and configured to be coupled to a silicon photonics device. In an example, a control block is configured to receive and send instruction(s) in a digital format to the communication block and is configured to receive and send signals in an analog format to communicate with the silicon photonics device.
    Type: Grant
    Filed: March 7, 2019
    Date of Patent: September 17, 2019
    Assignee: INPHI CORPORATION
    Inventors: Radhakrishnan L. Nagarajan, Chao Xu
  • Patent number: 10409758
    Abstract: The present invention provides an integrated system-on-chip device. The device is configured on a single silicon substrate member. The device has a data input/output interface provided on the substrate member. The device has an input/output block provided on the substrate member and coupled to the data input/output interface. The device has a signal processing block provided on the substrate member and coupled to the input/output block. The device has a driver module provided on the substrate member and coupled to the signal processing block. The device further includes a driver interface and coupled to the driver module and configured to be coupled to a silicon photonics device. In an example, a control block is configured to receive and send instruction(s) in a digital format to the communication block and is configured to receive and send signals in an analog format to communicate with the silicon photonics device.
    Type: Grant
    Filed: May 3, 2019
    Date of Patent: September 10, 2019
    Assignee: INPHI CORPORATION
    Inventors: Siddharth Sheth, Radhakrishnan L. Nagarajan
  • Publication number: 20190268075
    Abstract: The present invention is directed to a communication signal tracking system comprising an optical receiver including one or more delay line interferometers (DLIs) configured to demultiplex incoming optical signals and a transimpedance amplifier configured to convert the incoming optical signals to incoming electrical signals. The communication signal tracking system further includes a control module configured to calculate a bit-error-rate (BER) of the incoming electrical signals before forward-error correction decoding, and use the BER as a parameter for optimizing settings of the one or more DLIs in one or more iterations in a control loop and generating a back-channel data.
    Type: Application
    Filed: May 9, 2019
    Publication date: August 29, 2019
    Inventors: Todd ROPE, Sung CHOI, James STEWART, Radhakrishnan L. NAGARAJAN, Paul YU, Ilya LYUBOMIRSKY
  • Publication number: 20190258598
    Abstract: The present invention provides an integrated system-on-chip device. The device is configured on a single silicon substrate member. The device has a data input/output interface provided on the substrate member. The device has an input/output block provided on the substrate member and coupled to the data input/output interface. The device has a signal processing block provided on the substrate member and coupled to the input/output block. The device has a driver module provided on the substrate member and coupled to the signal processing block. The device further includes a driver interface and coupled to the driver module and configured to be coupled to a silicon photonics device. In an example, a control block is configured to receive and send instruction(s) in a digital format to the communication block and is configured to receive and send signals in an analog format to communicate with the silicon photonics device.
    Type: Application
    Filed: May 3, 2019
    Publication date: August 22, 2019
    Inventors: Siddharth SHETH, Radhakrishnan L. NAGARAJAN
  • Patent number: 10382125
    Abstract: The present invention is directed to communication systems and methods. According to an embodiment, a receiving optical transceiver determines signal quality for signals received from a transmitting optical transceiver. Information related to the signal quality is embedded into back-channel data and sent to the transmitting optical transceiver. The transmitting optical transceiver detects the presence of the back-channel data and adjusts one or more of its operating parameters based on the back-channel data. There are other embodiments as well.
    Type: Grant
    Filed: January 20, 2017
    Date of Patent: August 13, 2019
    Assignee: INPHI CORPORATION
    Inventors: Todd Rope, Radhakrishnan L. Nagarajan
  • Patent number: 10355804
    Abstract: An integrated apparatus with optical/electrical interfaces and protocol converter on a single silicon substrate. The apparatus includes an optical module comprising one or more modulators respectively coupled with one or more laser devices for producing a first optical signal to an optical interface and one or more photodetectors for detecting a second optical signal from the optical interface to generate a current signal. Additionally, the apparatus includes a transmit lane module coupled between the optical module and an electrical interface to receive a first electric signal from the electrical interface and provide a framing protocol for driving the one or more modulators. Furthermore, the apparatus includes a receive lane module coupled between the optical module and the electrical interface to process the current signal to send a second electric signal to the electrical interface.
    Type: Grant
    Filed: July 13, 2018
    Date of Patent: July 16, 2019
    Assignee: INPHI CORPORATION
    Inventor: Radhakrishnan L. Nagarajan
  • Publication number: 20190212507
    Abstract: A photonic transceiver apparatus in QSFP package. The apparatus includes a case having a base member, two partial side members, and a lid member to provide a spatial volume with an opening at a back end of the base member. Additionally, the apparatus includes a PCB, installed inside the spatial volume over the base member having a pluggable electrical connector at the back end. Further, the apparatus includes multiple optical transmitting devices in mini-transmit-optical-sub-assembly package, each being mounted on a common support structure and having a laser output port in reversed orientation toward the back end. Furthermore, the apparatus includes a silicon photonics chip, including a fiber-to-silicon attachment module, mounted on the PCB and coupled to a modulation driver module and a trans-impedance amplifier module. Moreover, the apparatus includes a pair of optical input/output ports being back connected to the fiber-to-silicon attachment module.
    Type: Application
    Filed: March 13, 2019
    Publication date: July 11, 2019
    Applicant: INPHI CORPORATION
    Inventors: Radhakrishnan L. NAGARAJAN, Peng-Chih LI, Masaki KATO
  • Publication number: 20190205285
    Abstract: The present invention provides an integrated system-on-chip device. The device is configured on a single silicon substrate member. The device has a data input/output interface provided on the substrate member. The device has an input/output block provided on the substrate member and coupled to the data input/output interface. The device has a signal processing block provided on the substrate member and coupled to the input/output block. The device has a driver module provided on the substrate member and coupled to the signal processing block. The device further includes a driver interface and coupled to the driver module and configured to be coupled to a silicon photonics device. In an example, a control block is configured to receive and send instruction(s) in a digital format to the communication block and is configured to receive and send signals in an analog format to communicate with the silicon photonics device.
    Type: Application
    Filed: March 7, 2019
    Publication date: July 4, 2019
    Inventors: Radhakrishnan L. NAGARAJAN, Chao XU
  • Patent number: 10333627
    Abstract: The present invention is directed to a communication signal tracking system comprising an optical receiver including one or more delay line interferometers (DLIs) configured to demultiplex incoming optical signals and a transimpedance amplifier configured to convert the incoming optical signals to incoming electrical signals. The communication signal tracking system further includes a control module configured to calculate a bit-error-rate (BER) of the incoming electrical signals before forward-error correction decoding, and use the BER as a parameter for optimizing settings of the one or more DLIs in one or more iterations in a control loop and generating a back-channel data.
    Type: Grant
    Filed: June 26, 2017
    Date of Patent: June 25, 2019
    Assignee: Inphi Corporation
    Inventors: Todd Rope, Sung Choi, James Stewart, Radhakrishnan L. Nagarajan, Paul Yu, Ilya Lyubomirsky
  • Patent number: 10289595
    Abstract: The present invention provides an integrated system-on-chip device. The device is configured on a single silicon substrate member. The device has a data input/output interface provided on the substrate member. The device has an input/output block provided on the substrate member and coupled to the data input/output interface. The device has a signal processing block provided on the substrate member and coupled to the input/output block. The device has a driver module provided on the substrate member and coupled to the signal processing block. The device further includes a driver interface and coupled to the driver module and configured to be coupled to a silicon photonics device. In an example, a control block is configured to receive and send instruction(s) in a digital format to the communication block and is configured to receive and send signals in an analog format to communicate with the silicon photonics device.
    Type: Grant
    Filed: July 20, 2018
    Date of Patent: May 14, 2019
    Assignee: INPHI CORPORATION
    Inventors: Siddharth Sheth, Radhakrishnan L. Nagarajan
  • Patent number: 10274688
    Abstract: A photonic transceiver apparatus in QSFP package. The apparatus includes a case having a base member, two partial side members, and a lid member to provide a spatial volume with an opening at a back end of the base member. Additionally, the apparatus includes a PCB, installed inside the spatial volume over the base member having a pluggable electrical connector at the back end. Further, the apparatus includes multiple optical transmitting devices in mini-transmit-optical-sub-assembly package, each being mounted on a common support structure and having a laser output port in reversed orientation toward the back end. Furthermore, the apparatus includes a silicon photonics chip, including a fiber-to-silicon attachment module, mounted on the PCB and coupled to a modulation driver module and a trans-impedance amplifier module. Moreover, the apparatus includes a pair of optical input/output ports being back connected to the fiber-to-silicon attachment module.
    Type: Grant
    Filed: June 20, 2018
    Date of Patent: April 30, 2019
    Assignee: INPHI CORPORATION
    Inventors: Radhakrishnan L. Nagarajan, Peng-Chih Li, Masaki Kato
  • Patent number: 10274680
    Abstract: An apparatus of polarization self-compensated delay line interferometer. The apparatus includes a first waveguide arm of a first material of a first length disposed between an input coupler and an output coupler and a second waveguide arm of the first material of a second length different from the first length disposed between the same input coupler and the same output coupler. The apparatus produces an interference spectrum with multiple periodic passband peaks where certain TE (transverse electric) and TM (transverse magnetic) polarization mode passband peaks are lined up. The apparatus further includes a section of waveguide of a birefringence material of a third length added to the second waveguide arm to induce a phase shift of the lined-up TE/TM passband peaks to a designated grid as corresponding polarization compensated channels of a wide optical band.
    Type: Grant
    Filed: June 22, 2018
    Date of Patent: April 30, 2019
    Assignee: INPHI CORPORATION
    Inventors: Masaki Kato, Radhakrishnan L. Nagarajan
  • Publication number: 20190108161
    Abstract: The present invention provides an integrated system-on-chip device. The device is configured on a single silicon substrate member. The device has a data input/output interface provided on the substrate member. The device has an input/output block provided on the substrate member and coupled to the data input/output interface. The device has a signal processing block provided on the substrate member and coupled to the input/output block. The device has a driver module provided on the substrate member and coupled to the signal processing block. The device further includes a driver interface and coupled to the driver module and configured to be coupled to a silicon photonics device. In an example, a control block is configured to receive and send instruction(s) in a digital format to the communication block and is configured to receive and send signals in an analog format to communicate with the silicon photonics device.
    Type: Application
    Filed: November 20, 2018
    Publication date: April 11, 2019
    Inventor: Radhakrishnan L. NAGARAJAN
  • Patent number: 10248616
    Abstract: The present invention provides an integrated system-on-chip device. The device is configured on a single silicon substrate member. The device has a data input/output interface provided on the substrate member. The device has an input/output block provided on the substrate member and coupled to the data input/output interface. The device has a signal processing block provided on the substrate member and coupled to the input/output block. The device has a driver module provided on the substrate member and coupled to the signal processing block. The device further includes a driver interface and coupled to the driver module and configured to be coupled to a silicon photonics device. In an example, a control block is configured to receive and send instruction(s) in a digital format to the communication block and is configured to receive and send signals in an analog format to communicate with the silicon photonics device.
    Type: Grant
    Filed: November 13, 2017
    Date of Patent: April 2, 2019
    Assignee: INPHI CORPORATION
    Inventors: Radhakrishnan L. Nagarajan, Chao Xu
  • Publication number: 20190067903
    Abstract: A packaged transmitter device includes a base member comprising a planar part mounted with a thermoelectric cooler, a transmitter, and a coupling lens assembly, and an assembling part connected to one side of the planar part. The device further includes a circuit board bended to have a first end region and a second end region being raised to a higher level. The first end region disposed on a top surface of the planar part includes multiple electrical connection patches respectively connected to the thermoelectric and the transmitter. The second end region includes an electrical port for external connection. Additionally, the device includes a cover member disposed over the planar part. Furthermore, the device includes a cylindrical member installed to the assembling part for enclosing an isolator aligned to the coupling lens assembly along its axis and connected to a fiber to couple optical signal from the transmitter to the fiber.
    Type: Application
    Filed: October 15, 2018
    Publication date: February 28, 2019
    Inventors: Radhakrishnan L. NAGARAJAN, Peng-Chih LI, Pi-Cheng LAW
  • Publication number: 20190041580
    Abstract: An optical dispersion compensator integrated with a silicon photonics system including a first phase-shifter coupled to a second phase-shifter in parallel on the silicon substrate characterized in an athermal condition. The dispersion compensator further includes a third phase-shifter on the silicon substrate to the first phase-shifter and the second phase-shifter through two 2×2 splitters to form an optical loop. A second entry port of a first 2×2 splitter is for coupling with an input fiber and a second exit port of a second 2×2 splitter is for coupling with an output fiber. The optical loop is characterized by a total phase delay tunable via each of the first phase-shifter, the second phase-shifter, and the third phase-shifter such that a normal dispersion (>0) at a certain wavelength in the input fiber is substantially compensated and independent of temperature.
    Type: Application
    Filed: October 11, 2018
    Publication date: February 7, 2019
    Inventors: Xiaoguang TU, Radhakrishnan L. NAGARAJAN, Masaki KATO