Patents by Inventor Krishna Mohan Rupavatharam

Krishna Mohan Rupavatharam 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: 11150536
    Abstract: Techniques for generating an arbitrary target electromagnetic signal with a nonlinear material, include determining a time varying target amplitude and target phase and an order n of a nonlinear material. For each time, a first set of nth roots of the target amplitude and a second set of nth roots of the target phase are determined. An input amplitude based on one value from the first set and an input phase based on one value from the second set is determined at each time. A difference between temporally successive values of phase is minimized. An electromagnetic signal is modulated to impose the input amplitude and phase to produce a modulated electromagnetic input signal that is introduced into the nonlinear material to produce a target electromagnetic signal.
    Type: Grant
    Filed: July 26, 2019
    Date of Patent: October 19, 2021
    Assignees: S2 CORPORATION, MONTANA STATE UNIVERSITY
    Inventors: Zeb William Barber, Calvin Harrington, Krishna Mohan Rupavatharam, Peter B. Sellin, Craig Benko
  • Publication number: 20200033696
    Abstract: Techniques for generating an arbitrary target electromagnetic signal with a nonlinear material, include determining a time varying target amplitude and target phase and an order n of a nonlinear material. For each time, a first set of nth roots of the target amplitude and a second set of nth roots of the target phase are determined. An input amplitude based on one value from the first set and an input phase based on one value from the second set is determined at each time. A difference between temporally successive values of phase is minimized. An electromagnetic signal is modulated to impose the input amplitude and phase to produce a modulated electromagnetic input signal that is introduced into the nonlinear material to produce a target electromagnetic signal.
    Type: Application
    Filed: July 26, 2019
    Publication date: January 30, 2020
    Inventors: Zeb William Barber, Calvin Harrington, Krishna Mohan Rupavatharam, Peter B. Sellin, Craig Benko
  • Patent number: 9853733
    Abstract: A method and apparatus includes an optical source for a single order single-sideband suppressed-carrier optical signal with a bandwidth that scales from over 4 gigaHertz or is at least 8 GHz from an optical carrier frequency. In an example embodiment, an apparatus includes a stable laser source configured to output an optical carrier signal at a carrier frequency. The apparatus includes a radio frequency electrical source configured to output an electrical radio frequency signal with a radio frequency bandwidth less than one octave. The apparatus also includes an optical modulator configured to output an optical signal with the optical carrier signal modulated by the radio frequency signal in a plurality of orders (harmonics) of optical frequency sidebands. The apparatus further includes an optical filter configured to pass one single order optical frequency sideband of the optical signal, which sideband does not overlap the sideband of any other harmonic.
    Type: Grant
    Filed: March 27, 2015
    Date of Patent: December 26, 2017
    Assignees: Montana State University, S2 Corporation
    Inventors: Colton Richard Stiffler, Scott Henry Bekker, Kristian D. Merkel, Randy R. Reibel, William Randall Babbitt, Krishna Mohan Rupavatharam
  • Publication number: 20150200727
    Abstract: A method and apparatus includes an optical source for a single order single-sideband suppressed-carrier optical signal with a bandwidth that scales from over 4 gigaHertz or is at least 8 GHz from an optical carrier frequency. In an example embodiment, an apparatus includes a stable laser source configured to output an optical carrier signal at a carrier frequency. The apparatus includes a radio frequency electrical source configured to output an electrical radio frequency signal with a radio frequency bandwidth less than one octave. The apparatus also includes an optical modulator configured to output an optical signal with the optical carrier signal modulated by the radio frequency signal in a plurality of orders (harmonics) of optical frequency sidebands. The apparatus further includes an optical filter configured to pass one single order optical frequency sideband of the optical signal, which sideband does not overlap the sideband of any other harmonic.
    Type: Application
    Filed: March 27, 2015
    Publication date: July 16, 2015
    Applicants: Montana State University, S2 Corporation
    Inventors: Colton Richard Stiffler, Scott Henry BEKKER, Kristian D. MERKEL, Randy R. REIBEL, William Randall BABBITT, Krishna Mohan RUPAVATHARAM
  • Patent number: 9020360
    Abstract: A method and apparatus includes an optical source for a single order single-sideband suppressed-carrier optical signal with a bandwidth that scales from over 1 gigaHertz to greater than 20 gigaHertz. In an example embodiment, an apparatus includes a stable laser source configured to output an optical carrier signal at a carrier frequency. The apparatus includes a radio frequency electrical source configured to output an electrical radio frequency signal with a radio frequency bandwidth less than one octave. The apparatus also includes an optical modulator configured to output an optical signal with the optical carrier signal modulated by the radio frequency signal in a plurality of orders of optical frequency sidebands. The apparatus further includes an optical filter configured to pass one single order optical frequency sideband of the optical signal.
    Type: Grant
    Filed: June 27, 2011
    Date of Patent: April 28, 2015
    Assignees: Montana State University, S2 Corporation
    Inventors: Colton Richard Stiffler, Scott Henry Bekker, Kristian D. Merkel, Randy R. Reibel, William R. Babbitt, Krishna Mohan Rupavatharam
  • Patent number: 8829471
    Abstract: Techniques for spatial spectral holography include a doped crystal comprising Thulium doped into a host crystal of Yttrium Lutetium Aluminum Garnet wherein a concentration of Thulium atoms is less than 3 atomic percent. Techniques further include an apparatus with a source for optical electromagnetic radiation and a cryocooler configured to maintain an operating temperature in a range from about 3 Kelvin to about 6 Kelvin. The cryocooler includes a first optical window. The apparatus also includes a doped crystal comprising Thulium doped into a host crystal of Yttrium Lutetium Aluminum Garnet disposed inside the cryocooler in a position to be illuminated by incident optical electromagnetic radiation derived from the source. The apparatus also includes a detector configured to detect optical electromagnetic radiation emitted from the doped crystal. Techniques include a method for using at least one of the above doped crystals.
    Type: Grant
    Filed: June 4, 2012
    Date of Patent: September 9, 2014
    Assignees: Montana State University, S2 Corporation
    Inventors: Kristian D. Merkel, Colton Richard Stiffler, Alex Woidtke, Aaron Traxinger, Randy W. Equall, Zeb Barber, Calvin Harrington, Krishna Mohan Rupavatharam, Charles W. Thiel, Rufus Cone
  • Publication number: 20120140236
    Abstract: An apparatus includes a single or dual output port, dual-drive Mach-Zehnder Interferometer configured to generate a first optical signal in one path, and to generate a second optical signal in a different path. The apparatus also includes an optical spectrum analyzer configured to receive output from at least one port of the dual-drive Mach-Zehnder Interferometer. A method includes causing radio frequency signals from two different antennae to modulate an optical carrier at a corresponding drive of a dual-drive Mach-Zehnder Interferometer, and causing output from at least one port of the Mach-Zehnder Interferometer to be directed to an optical spectrum analyzer. The method further comprises determining arrival angle at each of a plurality of frequencies in the radio frequency signals based on output from the optical spectrum analyzer.
    Type: Application
    Filed: June 14, 2011
    Publication date: June 7, 2012
    Applicants: S2 CORPORATION, MONTANA STATE UNIVERSITY
    Inventors: William R. Babbitt, Zeb Barber, Calvin Harrington, Kristian D. Merkel, Krishna Mohan Rupavatharam, Charles W. Thiel
  • Publication number: 20120002972
    Abstract: A method and apparatus includes an optical source for a single order single-sideband suppressed-carrier optical signal with a bandwidth that scales from over 1 gigaHertz to greater than 20 gigaHertz. In an example embodiment, an apparatus includes a stable laser source configured to output an optical carrier signal at a carrier frequency. The apparatus includes a radio frequency electrical source configured to output an electrical radio frequency signal with a radio frequency bandwidth less than one octave. The apparatus also includes an optical modulator configured to output an optical signal with the optical carrier signal modulated by the radio frequency signal in a plurality of orders of optical frequency sidebands. The apparatus further includes an optical filter configured to pass one single order optical frequency sideband of the optical signal.
    Type: Application
    Filed: June 27, 2011
    Publication date: January 5, 2012
    Applicants: S2 CORPORATION, MONTANA STATE UNIVERSITY
    Inventors: Colton Richard Stiffler, Scott Henry Bekker, Kristian D. Merkel, Randy R. Reibel, William R. Babbitt, Krishna Mohan Rupavatharam
  • Patent number: 7379652
    Abstract: Techniques for detecting optical spectral properties of a target are described. The technique includes providing an optical carrier which has an optical frequency bandwidth which is narrow compared to the width of the narrowest spectral feature of the target to be determined. This optical carrier is then electro-optically modulated with an RF frequency chirp, creating an optical chirp probe beam with a frequency chirped optical spectrum having upper and lower frequency chirped sidebands that have amplitudes sufficient to be detected at a detector. The sidebands are frequency bands arranged symmetrically around the optical carrier frequency. The attributes of a sideband include a start frequency, bandwidth and chirp rate. A probe beam is generated with the sidebands and directed onto a target having a physical property with optical frequency dependence. An optical response signal resulting from an interaction between the probe beam and the target is detected.
    Type: Grant
    Filed: April 14, 2006
    Date of Patent: May 27, 2008
    Assignee: Montana State University
    Inventors: Zachary Cole, Randy R. Reibel, Krishna Mohan Rupavatharam, William R. Babbitt, Kristian D. Merkel, Tiejun Chang