Patents by Inventor Stewart T. Wu

Stewart T. Wu 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: 10816463
    Abstract: A laser spectrometer includes a tunable laser assembly, a periodically-poled nonlinear optical crystal, with parallel polished input and output end faces, and a mechanism for controlling an entrance location of a pump input beam of the tunable laser on the input end face of the periodically-poled nonlinear optical crystal, such that the pump input beam traverses different grating periods of the periodically-poled nonlinear optical crystal.
    Type: Grant
    Filed: August 9, 2018
    Date of Patent: October 27, 2020
    Assignee: United States of America as represented by the Administrator of NASA
    Inventors: Kenji Numata, Haris Riris, Stewart T. Wu, Xiaoli Sun
  • Patent number: 10348052
    Abstract: The present invention relates to a laser system and method which enables fast, accurate laser frequency tuning. In particular, the present invention includes only one laser and only one absolute frequency locking loop to perform the same fast frequency tuning than previous seed laser systems.
    Type: Grant
    Filed: September 26, 2017
    Date of Patent: July 9, 2019
    Assignee: The United States of America as represented by the Administrator of NASA
    Inventors: Kenji Numata, Haris Riris, Stewart T. Wu
  • Patent number: 9964699
    Abstract: Disclosed herein are systems and methods related to use of hollow core photonic crystal fibers. A system includes a tube and a collimating lens configured in a first end of the tube, wherein a single mode fiber is coupled to a first end of the collimating lens. A second lens is supported by a structure at a second end of the tube, the second lens receiving a first signal from a second end of the collimating lens and outputting a second signal that is coupled into a first end of a hollow core photonic crystal fiber. A first gas tube is configured to introduce gas through the structure into a chamber and a sealant seals at least one of the collimating lens and the structure within the tube. An output signal is received at a detector that catches the entire beam to suppress multiple-mode beating noise.
    Type: Grant
    Filed: September 21, 2015
    Date of Patent: May 8, 2018
    Assignee: The United States of America, as represented by the Administrator of the National Aeronautics and Space Administraion
    Inventors: Jeffrey R. Chen, Kenji Numata, Stewart T. Wu
  • Publication number: 20160327735
    Abstract: Disclosed herein are systems and methods related to use of hollow core photonic crystal fibers. A system includes a tube and a collimating lens configured in a first end of the tube, wherein a single mode fiber is coupled to a first end of the collimating lens. A second lens is supported by a structure at a second end of the tube, the second lens receiving a first signal from a second end of the collimating lens and outputting a second signal that is coupled into a first end of a hollow core photonic crystal fiber. A first gas tube is configured to introduce gas through the structure into a chamber and a sealant seals at least one of the collimating lens and the structure within the tube. An output signal is received at a detector that catches the entire beam to suppress multiple-mode beating noise.
    Type: Application
    Filed: September 21, 2015
    Publication date: November 10, 2016
    Inventors: JEFFREY R. CHEN, KENJI NUMATA, STEWART T. WU
  • Patent number: 9065242
    Abstract: An apparatus and method is provided to enable precision and fast laser frequency tuning. For instance, a fast tunable slave laser may be dynamically offset-locked to a reference laser line using an optical phase-locked loop. The slave laser is heterodyned against a reference laser line to generate a beatnote that is subsequently frequency divided. The phase difference between the divided beatnote and a reference signal may be detected to generate an error signal proportional to the phase difference. The error signal is converted into appropriate feedback signals to phase lock the divided beatnote to the reference signal. The slave laser frequency target may be rapidly changed based on a combination of a dynamically changing frequency of the reference signal, the frequency dividing factor, and an effective polarity of the error signal. Feed-forward signals may be generated to accelerate the slave laser frequency switching through laser tuning ports.
    Type: Grant
    Filed: May 17, 2012
    Date of Patent: June 23, 2015
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics Space Administration
    Inventors: Jeffrey R. Chen, Kenji Numata, Stewart T. Wu, Guangning Yang
  • Publication number: 20130308663
    Abstract: An apparatus and method is provided to enable precision and fast laser frequency tuning. For instance, a fast tunable slave laser may be dynamically offset-locked to a reference laser line using an optical phase-locked loop. The slave laser is heterodyned against a reference laser line to generate a beatnote that is subsequently frequency divided. The phase difference between the divided beatnote and a reference signal may be detected to generate an error signal proportional to the phase difference. The error signal is converted into appropriate feedback signals to phase lock the divided beatnote to the reference signal. The slave laser frequency target may be rapidly changed based on a combination of a dynamically changing frequency of the reference signal, the frequency dividing factor, and an effective polarity of the error signal. Feed-forward signals may be generated to accelerate the slave laser frequency switching through laser tuning ports.
    Type: Application
    Filed: May 17, 2012
    Publication date: November 21, 2013
    Inventors: JEFFREY R. CHEN, Kenji Numata, Stewart T. Wu, Guangning Yang