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).

  • 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
  • Patent number: 10094664
    Abstract: In one embodiment, a method is provided. The method comprises generating a waveform; measuring signals representative of angular rotation rate in a linear region of the waveform; and diminishing bias error about at least one of a waveform's maxima and minima.
    Type: Grant
    Filed: November 23, 2016
    Date of Patent: October 9, 2018
    Assignee: Honeywell International Inc.
    Inventors: Glen A. Sanders, Lee K. Strandjord, Tiequn Qiu
  • Publication number: 20180275254
    Abstract: In one embodiment, a method of operating a glare reduction and ranging optical system having an image sensor with pixels is provided.
    Type: Application
    Filed: May 24, 2017
    Publication date: September 27, 2018
    Inventors: Jianfeng Wu, Matthew Wade Puckett, Tiequn Qiu, Glen A. Sanders
  • Publication number: 20180143022
    Abstract: In one embodiment, a method is provided. The method comprises generating a waveform; measuring signals representative of angular rotation rate in a linear region of the waveform; and diminishing bias error about at least one of a waveform's maxima and minima.
    Type: Application
    Filed: November 23, 2016
    Publication date: May 24, 2018
    Inventors: Glen A. Sanders, Lee K. Strandjord, Tiequn Qiu
  • Publication number: 20180081113
    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: May 10, 2017
    Publication date: March 22, 2018
    Inventors: Matthew Wade Puckett, Jianfeng Wu, Mary Salit, Tiequn Qiu
  • Publication number: 20180081112
    Abstract: A waveguide device comprises a substrate having an upper surface and a first width; a cladding layer over the upper surface of the substrate, the cladding layer comprising a first material having a first refractive index, wherein the cladding layer has a second width that is less than the first width; and an optical core surrounded by the cladding layer, the optical core comprising a second material having a second refractive index that is higher that the first refractive index such that an optical signal will propagate through the optical core. The cladding layer that surrounds the optical core has a thickness configured to substantially confine acoustic waves to the cladding layer when the optical signal propagates through the optical core.
    Type: Application
    Filed: May 10, 2017
    Publication date: March 22, 2018
    Inventors: Matthew Wade Puckett, Tiequn Qiu, Mary K. Salit, Jianfeng Wu
  • Patent number: 9772187
    Abstract: A ring laser gyroscope (RLG) is provided. The RLG includes a primary resonator, a secondary resonator, and an optical source to provide a pump field. The pump field in the primary resonator stimulates an optical gain curve at a first stokes wave frequency. A first order SBS field stimulates a second optical gain curve at a second stokes wave frequency. The second order SBS gain gives rise to a frequency-shifted field propagating in the first direction. The fraction of the pump field that couples out of the primary resonator, through the secondary resonator, and out of the secondary resonator is larger than the fraction of: the first order SBS field that couples out of the primary resonator, through the secondary resonator, and out of the secondary resonator; and a second order SBS field that couples out of the primary resonator, through the secondary resonator, and out of the secondary resonator.
    Type: Grant
    Filed: February 24, 2016
    Date of Patent: September 26, 2017
    Assignee: Honeywell International Inc.
    Inventors: Mary K. Salit, Jianfeng Wu, Tiequn Qiu
  • Publication number: 20170241784
    Abstract: A ring laser gyroscope (RLG) is provided. The RLG includes a primary resonator, a secondary resonator, and an optical source to provide a pump field. The pump field in the primary resonator stimulates an optical gain curve at a first stokes wave frequency. A first order SBS field stimulates a second optical gain curve at a second stokes wave frequency. The second order SBS gain gives rise to a frequency-shifted field propagating in the first direction. The fraction of the pump field that couples out of the primary resonator, through the secondary resonator, and out of the secondary resonator is larger than the fraction of: the first order SBS field that couples out of the primary resonator, through the secondary resonator, and out of the secondary resonator; and a second order SBS field that couples out of the primary resonator, through the secondary resonator, and out of the secondary resonator.
    Type: Application
    Filed: February 24, 2016
    Publication date: August 24, 2017
    Inventors: Mary K. Salit, Jianfeng Wu, Tiequn Qiu
  • Patent number: 9733084
    Abstract: A ring laser gyroscope is provided. The ring laser gyroscope includes an optical ring resonator, an optical source to provide a pump beam at a pump frequency, a beat detector, and an optical clock detector. The pump beam is coupled to the optical ring resonator in the first direction and stimulates a first optical gain curve at a first stokes wave frequency downshifted by a Brillouin stokes frequency from the pump frequency. A first order stimulated Brillouin scattering (SBS) beam propagates in the second direction and a second order SBS beam propagates in the first direction. The beat detector produces an optical beat signal that varies as a function of a frequency difference between the first order SBS beam and the second order SBS beam. The optical clock detector generates a reference frequency signal based on two co-propagating beams.
    Type: Grant
    Filed: October 13, 2015
    Date of Patent: August 15, 2017
    Assignee: Honeywell International Inc.
    Inventors: Mary K. Salit, Jianfeng Wu, Tiequn Qiu
  • Patent number: 9683830
    Abstract: A fiber light source comprises a laser pump configured to generate a pump laser beam at a predetermined wavelength; a first segment of rare earth doped fiber; a second segment of rare earth doped fiber; and an optical coupler coupled to a first end of the first segment and a first end of the second segment. The optical coupler is configured to split the pump laser beam based on a power coupling ratio. The first segment generates a first stimulated emission having a first mean wavelength sensitivity to pump laser power fluctuations and the second segment generates a second stimulated emission having a second mean wavelength sensitivity to pump laser power fluctuations such that a combined stimulated emission is approximately insensitive to pump laser power fluctuations.
    Type: Grant
    Filed: December 10, 2014
    Date of Patent: June 20, 2017
    Assignee: Honeywell International Inc
    Inventors: Tiequn Qiu, Steven J. Sanders
  • Publication number: 20170082420
    Abstract: A fiber light source comprises a laser pump configured to generate a pump laser beam at a predetermined wavelength; a first segment of rare earth doped fiber; a second segment of rare earth doped fiber; and an optical coupler coupled to a first end of the first segment and a first end of the second segment. The optical coupler is configured to split the pump laser beam based on a power coupling ratio. The first segment generates a first stimulated emission having a first mean wavelength sensitivity to pump laser power fluctuations and the second segment generates a second stimulated emission having a second mean wavelength sensitivity to pump laser power fluctuations such that a combined stimulated emission is approximately insensitive to pump laser power fluctuations.
    Type: Application
    Filed: December 10, 2014
    Publication date: March 23, 2017
    Inventors: Tiequn Qiu, Steven J. Sanders
  • Publication number: 20170067743
    Abstract: A ring laser gyroscope is provided. The ring laser gyroscope includes an optical ring resonator, an optical source to provide a pump beam at a pump frequency, a beat detector, and an optical clock detector. The pump beam is coupled to the optical ring resonator in the first direction and stimulates a first optical gain curve at a first stokes wave frequency downshifted by a Brillouin stokes frequency from the pump frequency. A first order stimulated Brillouin scattering (SBS) beam propagates in the second direction and a second order SBS beam propagates in the first direction. The beat detector produces an optical beat signal that varies as a function of a frequency difference between the first order SBS beam and the second order SBS beam. The optical clock detector generates a reference frequency signal based on two co-propagating beams.
    Type: Application
    Filed: October 13, 2015
    Publication date: March 9, 2017
    Inventors: Mary K. Salit, Jianfeng Wu, Tiequn Qiu
  • Patent number: 9587945
    Abstract: A resonator fiber optic gyroscope comprises a master laser that emits a reference optical signal, a first slave laser that emits a clockwise optical signal, and a second slave laser that emits a counter-clockwise optical signal. A resonator ring cavity in optical communication with the first slave laser and second slave laser is configured to receive the optical signals from the slave lasers without receiving the reference optical signal. A reflected optical signal from the cavity is directed to a feedback laser stabilization loop for the master laser that includes a common modulation frequency scheme. A frequency of the optical signal from the master laser is indirectly locked onto a resonance frequency of the cavity with a fixed frequency offset, which is determined by a relative frequency between the optical signal of the first slave laser or the second slave laser, and the optical signal of the master laser.
    Type: Grant
    Filed: June 23, 2014
    Date of Patent: March 7, 2017
    Assignee: Honeywell International Inc.
    Inventors: Lee K. Strandjord, Glen A. Sanders, Tiequn Qiu
  • Patent number: 9537283
    Abstract: One embodiment is directed towards a stabilized laser including a laser to produce light at a frequency and a resonator coupled to the laser such that the light from the laser circulates therethrough. The laser also includes Pound-Drever-Hall (PDH) feedback electronics configured to adjust the frequency of the light from the laser to reduce phase noise in response to light sensed at the reflection port of the resonator and transmission port feedback electronics configured to adjust the frequency of the light from the laser toward resonance of the resonator at the transmission port in response to the light sensed at the transmission port of the resonator, wherein the transmission port feedback electronics adjust the frequency at a rate at least ten times slower than the PDH feedback electronics.
    Type: Grant
    Filed: November 18, 2014
    Date of Patent: January 3, 2017
    Assignee: Honeywell International Inc.
    Inventors: Lee K. Strandjord, Tiequn Qiu, Glen A. Sanders
  • Patent number: 9459101
    Abstract: Systems and methods for fiber optic gyroscopes are provided. In one embodiment, a resonating fiber optic gyroscope comprises: first and second laser sources producing first and second optical beams; a first resonator having a hub comprising a hub material, wherein the first and second optical beams circulate within the first resonator in opposite directions; a second resonator having a hub comprising the hub material, wherein the first and second optical beams circulate within the second resonator in opposite directions; first and second servo loops; the first loop controls the first laser source based on a beam that has circulated through the first resonator and a beam that has circulated through the second resonator; the second servo loop controls the second laser source based on a beam that has circulated through the first resonator and a beam that has circulated through the second resonator; and a rotation rate detection circuit.
    Type: Grant
    Filed: June 15, 2015
    Date of Patent: October 4, 2016
    Assignee: Honeywell International Inc.
    Inventors: Lee K. Strandjord, Glen A. Sanders, Tiequn Qiu
  • Patent number: 9441969
    Abstract: A multi-core transport system for a resonant fiber optic gyroscope is provided. The transport system has a transport fiber configured to transmit a clockwise signal and a counterclockwise signal, wherein the transport fiber has at least a first core and a second core. The first core and second core are configured such that when the first core imparts a first effect on the clockwise signal, the second core imparts a second effect on the counterclockwise signal, wherein the second effect substantially mirrors the first effect. The system further comprises a first coupler configured to optically couple the clockwise signal to the first core, and the counterclockwise signal to the second core; and a second coupler configured to optically couple the clockwise signal from the first core to a resonator, and the counterclockwise signal from the second core to the resonator.
    Type: Grant
    Filed: December 2, 2013
    Date of Patent: September 13, 2016
    Assignee: Honeywell International Inc.
    Inventors: Tiequn Qiu, Glen A. Sanders, Lee K. Strandjord
  • Patent number: 9395184
    Abstract: Systems and methods for a resonant fiber optic gyroscope with a polarizing crystal waveguide coupler are provided. In one embodiment, an optical fiber resonator comprises: a polarizing single crystal material having a first crystal lattice axis; a first waveguide formed in the crystal material; a second waveguide formed in the crystal material running parallel to the first waveguide; and an optical fiber sensing coil. The first waveguide comprises a bend that approaches the second waveguide defining a coupling region between the first and second waveguides. The first and second waveguides are polarized to guide light having a polarization state aligned to the first crystal lattice axis. The second waveguide and the sensing coil are coupled into a resonator configuration forming a ring resonator, the second waveguide comprising a first port coupled to a first end of the coil, and a second port coupled to a second end of the coil.
    Type: Grant
    Filed: August 18, 2014
    Date of Patent: July 19, 2016
    Assignee: Honeywell International Inc.
    Inventors: Tiequn Qiu, Glen A. Sanders, Lee K. Strandjord
  • Publication number: 20160204571
    Abstract: Systems and methods for an optical frequency comb stimulated Brillouin scattering gyroscope with a rigid optical waveguide resonator are provided. In one embodiment, a system comprises: a light source that produces an optical frequency comb comprising a multiple-frequency light field; a rigid optical waveguide resonator coupled to the light source, wherein a recirculating optical frequency comb produced from the optical frequency comb propagates in a first direction around the rigid optical waveguide resonator and generates within the rigid optical waveguide a SBS light field comprising at least one SBS frequency component, and wherein one or more optical frequency components of the recirculating optical frequency comb are locked on resonance peaks of the rigid optical waveguide resonator; and an optical mixer configured to produce an optical beat signal that varies as a function of a frequency difference between the stimulated Brillouin scattering light field and the recirculating optical frequency comb.
    Type: Application
    Filed: April 7, 2015
    Publication date: July 14, 2016
    Inventors: Jianfeng Wu, Mary K. Salit, Lee K. Strandjord, Glen A. Sanders, Tiequn Qiu