Patents by Inventor Tiequn Qiu

Tiequn Qiu 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: 20220021177
    Abstract: Systems and methods for ring laser gyroscopes (RLGs) are provided. An RLG includes a traveling-wave resonator cavity with three or more mirrors and a gain medium positioned in the traveling-wave resonator cavity between two of the three or more mirrors. The gain medium is a solid-state gain medium or a nonlinear optical medium. The RLG further includes a first pump laser and a second pump laser to pump the gain medium in different directions and generate first and second lasing signals that traverse the traveling-wave resonator cavity in a opposite directions. The RLG further includes first and second photodetectors to measure levels of the first and second lasing signals. The RLG further includes at least one processor configured to adjust a power level of the first pump laser and/or a power level of the second pump laser based on the measured power levels of the first and second lasing signals.
    Type: Application
    Filed: July 20, 2020
    Publication date: January 20, 2022
    Applicant: Honeywell International Inc.
    Inventors: Tiequn Qiu, Teresa Marta, Jianfeng Wu
  • Patent number: 11002545
    Abstract: Systems and methods for performing SHD switching for RFOGS are provided herein. A system includes a resonator in which light resonates; at least one laser source that produces first and second optical beams; heterodyne modulators that modulate the first and second optical beams at a heterodyne frequency plus a modulation frequency offset to produce multiple sideband optical beams, wherein the modulation frequency offset has a different sign for the first and second optical beams; a frequency switching controller that alternatingly switches the signs of the modulation frequency offset applied to the first and second optical beams, wherein the heterodyne modulation of the first and second optical beams are on average at the heterodyne frequency; at least one coupler that couples the sideband optical beams into the resonator; a feedback control that detects the sideband optical beams transmitted from the resonator and, in response, adjusts frequencies of the optical beams.
    Type: Grant
    Filed: August 20, 2019
    Date of Patent: May 11, 2021
    Assignee: Honeywell International Inc.
    Inventors: Lee K. Strandjord, Glen A. Sanders, Jianfeng Wu, Tiequn Qiu, Marc Smiciklas
  • Publication number: 20210055108
    Abstract: Systems and methods for performing SHD switching for RFOGS are provided herein. A system includes a resonator in which light resonates; at least one laser source that produces first and second optical beams; heterodyne modulators that modulate the first and second optical beams at a heterodyne frequency plus a modulation frequency offset to produce multiple sideband optical beams, wherein the modulation frequency offset has a different sign for the first and second optical beams; a frequency switching controller that alternatingly switches the signs of the modulation frequency offset applied to the first and second optical beams, wherein the heterodyne modulation of the first and second optical beams are on average at the heterodyne frequency; at least one coupler that couples the sideband optical beams into the resonator; a feedback control that detects the sideband optical beams transmitted from the resonator and, in response, adjusts frequencies of the optical beams.
    Type: Application
    Filed: August 20, 2019
    Publication date: February 25, 2021
    Applicant: Honeywell International Inc.
    Inventors: Lee K. Strandjord, Glen A. Sanders, Jianfeng Wu, Tiequn Qiu, Marc Smiciklas
  • Patent number: 10914587
    Abstract: Techniques are provided for correcting for time varying changes to a gyroscope incorporating a resonator and/or to an environment in which the gyroscope is located, and which affect the resonator. Free spectral range of the gyroscope, which varies with such changes, is determined and is used to correct at least one of gyroscope bias and scale factor.
    Type: Grant
    Filed: July 23, 2019
    Date of Patent: February 9, 2021
    Assignee: Honeywell International Inc.
    Inventors: Glen A. Sanders, Lee K. Strandjord, Tiequn Qiu, Marc Smiciklas, Norman Gerard Tarleton
  • Publication number: 20210025709
    Abstract: Techniques are provided for correcting for time varying changes to a gyroscope incorporating a resonator and/or to an environment in which the gyroscope is located, and which affect the resonator. Free spectral range of the gyroscope, which varies with such changes, is determined and is used to correct at least one of gyroscope bias and scale factor.
    Type: Application
    Filed: July 23, 2019
    Publication date: January 28, 2021
    Applicant: Honeywell International Inc.
    Inventors: Glen A. Sanders, Lee K. Strandjord, Tiequn Qiu, Marc Smiciklas, Norman Gerard Tarleton
  • Publication number: 20200388984
    Abstract: A micro femtosecond laser with reduced radiation and temperature sensitivity is provided. The laser includes a housing with a radiation shield. Optical components that include a micro gain element are received within the housing. An input end of a pump light delivering fiber is positioned outside the housing. An output end of the pump light delivering fiber is positioned within the housing to deliver input beams to the optical components. A light signal generating pump is used to generate the input beams that are communicated to the input end of the pump light delivering fiber. A first end of a hollow core fiber is positioned within the housing to be in optical communication with the optical components. A second end of the hollow core fiber is positioned outside the housing. A partially reflective output coupling mirror is in optical communication with the second end of the hollow core fiber.
    Type: Application
    Filed: June 7, 2019
    Publication date: December 10, 2020
    Applicant: Honeywell International Inc.
    Inventors: Tiequn Qiu, Chellappan Narayanan, Jeffrey Earl Lewis, Sorin Mosor
  • Publication number: 20200220319
    Abstract: In an example, a mode-locked laser includes a resonator cavity having a saturable absorber, a hollow core fiber coupled to the saturable absorber, and an optical amplifier optically coupled between the hollow core fiber and an output coupler. The mode-locked laser further includes a first pump laser and a wavelength division multiplexer coupled to the first pump laser. The wavelength division multiplexer is configured to couple light from the first pump laser into the resonator cavity to pump the optical amplifier. The mode-locked laser is configured to generate a pulse waveform at a repetition rate of approximately 100 MHz to 200 MHz.
    Type: Application
    Filed: January 9, 2019
    Publication date: July 9, 2020
    Applicant: Honeywell International Inc.
    Inventors: Chellappan Narayanan, Jeffrey Earl Lewis, Sorin Mosor, Tiequn Qiu
  • Patent number: 10627654
    Abstract: An acousto-optic waveguide device comprises a substrate comprising a first material having a first refractive index and a first acoustic velocity; a cladding layer over the substrate, the cladding layer comprising a second material having a second refractive index that is distinct from the first refractive index, the second material having a second acoustic velocity that is distinct from the first acoustic velocity; and an optical core surrounded by the cladding layer, the optical core comprising a third material having a third refractive index that is higher that the first refractive index and the second refractive index, the third material having a third acoustic velocity that is distinct from the first acoustic velocity and the second acoustic velocity. The cladding layer that surrounds the optical core has a thickness configured to substantially confine acoustic waves to the cladding layer when an optical signal propagates through the optical core.
    Type: Grant
    Filed: March 18, 2019
    Date of Patent: April 21, 2020
    Assignee: Honeywell International Inc.
    Inventors: Matthew Wade Puckett, Jianfeng Wu, Mary Salit, Tiequn Qiu
  • Publication number: 20200096698
    Abstract: An acousto-optic waveguide device comprises a substrate comprising a first material having a first refractive index and a first acoustic velocity; a cladding layer over the substrate, the cladding layer comprising a second material having a second refractive index that is distinct from the first refractive index, the second material having a second acoustic velocity that is distinct from the first acoustic velocity; and an optical core surrounded by the cladding layer, the optical core comprising a third material having a third refractive index that is higher that the first refractive index and the second refractive index, the third material having a third acoustic velocity that is distinct from the first acoustic velocity and the second acoustic velocity. The cladding layer that surrounds the optical core has a thickness configured to substantially confine acoustic waves to the cladding layer when an optical signal propagates through the optical core.
    Type: Application
    Filed: March 18, 2019
    Publication date: March 26, 2020
    Applicant: Honeywell International Inc.
    Inventors: Matthew Wade Puckett, Jianfeng Wu, Mary Salit, Tiequn Qiu
  • Publication number: 20200072609
    Abstract: A method is provided. The method comprises: receiving a first optical signal and a second optical signal; injecting the first optical signal into an optical resonator so that the first optical signal propagates in a first direction through the optical resonator; injecting the second optical signal into the optical resonator so that the second optical signal propagates in a second direction through the optical resonator, which is opposite to the first direction; filtering an optical signal propagating in the first direction of the optical resonator with a first common polarizer having the first polarization; and filtering an optical signal propagating in the second direction of the optical resonator with the first common polarizer.
    Type: Application
    Filed: September 4, 2018
    Publication date: March 5, 2020
    Applicant: Honeywell International Inc.
    Inventors: Neil A. Krueger, Tiequn Qiu, Lee K. Strandjord, Glen A. Sanders
  • Patent number: 10578722
    Abstract: In one embodiment, a method of operating a glare reduction and ranging optical system having an image sensor with pixels is provided.
    Type: Grant
    Filed: May 24, 2017
    Date of Patent: March 3, 2020
    Assignee: Honeywell International Inc.
    Inventors: Jianfeng Wu, Matthew Wade Puckett, Tiequn Qiu, Glen A. Sanders
  • Patent number: 10415971
    Abstract: Bias error in a resonant fiber optic gyroscope (RFOG) is diminished by reducing polarization mismatch between a polarization Eigenstate of optical signals propagating inside of a resonator of the RFOG and the polarization of optical signals being injected into the resonator of the RFOG. The polarization mismatch is reduced by filtering the optical signals circulating in the resonator and the optical signals injected into the resonator with common polarizers.
    Type: Grant
    Filed: January 15, 2018
    Date of Patent: September 17, 2019
    Assignee: Honeywell International Inc.
    Inventors: Neil Krueger, Mary Salit, Barbara Vizenor, Glen A. Sanders, Lee K. Strandjord, Tiequn Qiu
  • Patent number: 10365107
    Abstract: Systems and methods for reducing polarization-related bias errors in RFOGS are described herein. In certain implementations, an RFOG system includes a fiber optic resonator, one or more laser sources, wherein light from the laser sources launches first and second optical beams into the fiber optic resonator in opposite directions, and an electro-optically tunable devices in the resonator path configured to modulate the phase difference between polarization components in the first and second optical beams as the optical beams propagate within the fiber optic resonator. The system further includes at least one photodetector, wherein the polarization components of the first and second optical beams are incident on the photodetector, wherein the at least one photodetector provides an electrical signal, and at least one processing unit configured to receive the electrical signal and calculate a rotation rate for the RFOG and provide a drive signal for the electro-optically tunable device.
    Type: Grant
    Filed: August 3, 2017
    Date of Patent: July 30, 2019
    Assignee: Honeywell International Inc.
    Inventors: Glen A. Sanders, Marc Smiciklas, Tiequn Qiu, Jianfeng Wu, Lee K. Strandjord
  • Publication number: 20190219396
    Abstract: Bias error in a resonant fiber optic gyroscope (RFOG) is diminished by reducing polarization mismatch between a polarization Eigenstate of optical signals propagating inside of a resonator of the RFOG and the polarization of optical signals being injected into the resonator of the RFOG. The polarization mismatch is reduced by filtering the optical signals circulating in the resonator and the optical signals injected into the resonator with common polarizers.
    Type: Application
    Filed: January 15, 2018
    Publication date: July 18, 2019
    Inventors: Neil Krueger, Mary Salit, Barbara Vizenor, Glen A. Sanders, Lee K. Strandjord, Tiequn Qiu
  • Patent number: 10288429
    Abstract: In one embodiment, a method is provided. The method comprises transmitting a first laser pump signal to an optical resonator; adjusting a frequency of the first laser pump signal; generating a first order Stokes signal from the first laser pump signal in an optical resonator; measuring a first beat signal frequency; ceasing transmission of the first laser pump signal to the optical resonator; transmitting a second laser pump signal to the optical resonator; adjusting a frequency of the second laser pump signal; generating a first order Stokes signal from the second laser pump signal in the optical resonator; and measuring a second beat signal frequency; ceasing transmission of the second laser pump signal to the optical resonator.
    Type: Grant
    Filed: June 1, 2017
    Date of Patent: May 14, 2019
    Assignee: Honeywell International Inc.
    Inventors: Tiequn Qiu, Jianfeng Wu, Matthew Wade Puckett
  • Patent number: 10281646
    Abstract: An acousto-optic waveguide device comprises a substrate comprising a first material having a first refractive index and a first acoustic velocity; a cladding layer over the substrate, the cladding layer comprising a second material having a second refractive index that is distinct from the first refractive index, the second material having a second acoustic velocity that is distinct from the first acoustic velocity; and an optical core surrounded by the cladding layer, the optical core comprising a third material having a third refractive index that is higher that the first refractive index and the second refractive index, the third material having a third acoustic velocity that is distinct from the first acoustic velocity and the second acoustic velocity. The cladding layer that surrounds the optical core has a thickness configured to substantially confine acoustic waves to the cladding layer when an optical signal propagates through the optical core.
    Type: Grant
    Filed: May 10, 2017
    Date of Patent: May 7, 2019
    Assignee: Honeywell International Inc.
    Inventors: Matthew Wade Puckett, Jianfeng Wu, Mary Salit, Tiequn Qiu
  • Publication number: 20190041215
    Abstract: Systems and methods for reducing polarization-related bias errors in RFOGS are described herein. In certain implementations, an RFOG system includes a fiber optic resonator, one or more laser sources, wherein light from the laser sources launches first and second optical beams into the fiber optic resonator in opposite directions, and an electro-optically tunable devices in the resonator path configured to modulate the phase difference between polarization components in the first and second optical beams as the optical beams propagate within the fiber optic resonator. The system further includes at least one photodetector, wherein the polarization components of the first and second optical beams are incident on the photodetector, wherein the at least one photodetector provides an electrical signal, and at least one processing unit configured to receive the electrical signal and calculate a rotation rate for the RFOG and provide a drive signal for the electro-optically tunable device.
    Type: Application
    Filed: August 3, 2017
    Publication date: February 7, 2019
    Inventors: Glen A. Sanders, Marc Smiciklas, Tiequn Qiu, Jianfeng Wu, Lee K. Strandjord
  • Patent number: 10197397
    Abstract: Systems and methods for a small low cost resonator fiber optic gyroscope (RFOG) with reduced optical errors are provided. In one embodiment, a RFOG comprises: a light source; an optical chip configured to couple a clockwise optical signal and a counterclockwise optical signal from the light source into a fiber optic resonator and couple the clockwise optical signal and the counterclockwise optical signal from the fiber optic resonator to at least one photodetector. The fiber optic resonator comprises a fiber optic coil having a first end point and a second end point. The fiber optic coil has a 90-degree splice located substantially half-way between the first end point and the second end point, is wrapped around a first fiber stretcher located between the first end point and the 90-degree splice, and is wrapped around a second fiber stretcher that is located between the second end point and the 90-degree splice.
    Type: Grant
    Filed: October 28, 2014
    Date of Patent: February 5, 2019
    Assignee: Honeywell International Inc.
    Inventors: Glen A. Sanders, Lee K. Strandjord, Tiequn Qiu, Jianfeng Wu
  • Publication number: 20190017824
    Abstract: In one embodiment, a method is provided. The method comprises transmitting a first laser pump signal to an optical resonator; adjusting a frequency of the first laser pump signal; generating a first order Stokes signal from the first laser pump signal in an optical resonator; measuring a first beat signal frequency; ceasing transmission of the first laser pump signal to the optical resonator; transmitting a second laser pump signal to the optical resonator; adjusting a frequency of the second laser pump signal; generating a first order Stokes signal from the second laser pump signal in the optical resonator; and measuring a second beat signal frequency; ceasing transmission of the second laser pump signal to the optical resonator.
    Type: Application
    Filed: June 1, 2017
    Publication date: January 17, 2019
    Inventors: Tiequn Qiu, Jianfeng Wu, Matthew Wade Puckett
  • Patent number: 10101160
    Abstract: One embodiment is directed towards a resonator fiber optic gyroscope (RFOG) including a resonator, one or more light sources coupled to the resonator, and resonance tracking electronics coupled to the resonator. The one or more light sources are configured to produce at least two light beams for input into the fiber coil, the at least two light beams including a first light beam at a first frequency and a second light beam at a second frequency, the first and second frequencies locked to nearby resonance modes of the resonator. The resonance tracking electronics are configured to process output light from the resonator and generate a signal therefrom, the signal indicative of a rotation rate of the resonator. The fiber coil has approximately zero total accumulated chromatic dispersion at the first frequency and the second frequency of the first light beam and the second light beam.
    Type: Grant
    Filed: July 9, 2013
    Date of Patent: October 16, 2018
    Assignee: Honeywell International Inc.
    Inventors: Tiequn Qiu, Glen A. Sanders, Lee K. Strandjord