Patents by Inventor Qilai Zhao

Qilai Zhao 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: 11862925
    Abstract: A tunable narrow-linewidth photo-generated microwave source based on polarization control includes a high-reflectivity fiber grating, a high-gain fiber, a low-reflectivity polarization-maintaining fiber grating, a stress adjusting device, a single-mode semiconductor pump laser, an optical wavelength division multiplexer, a polarization beam splitter, a polarization controller, an optical coupler, and a photoelectric detector. Birefringence distribution in the low-reflectivity polarization-maintaining fiber grating is controlled by adjusting a stress magnitude of the stress adjusting device to the low-reflectivity polarization fiber grating, thereby controlling a laser frequency working in different polarization modes in a resonant cavity, and a tunable narrow-linewidth photo-generated microwave source is generated by a beat-frequency technology using a dual-wavelength narrow-linewidth laser with variable frequency intervals.
    Type: Grant
    Filed: October 30, 2018
    Date of Patent: January 2, 2024
    Assignee: SOUTH CHINA UNIVERSITY OF TECHNOLOGY
    Inventors: Shanhui Xu, Qilai Zhao, Zhitao Zhang, Changsheng Yang, Zhouming Feng, Zhongmin Yang
  • Publication number: 20220131329
    Abstract: The invention discloses a multi-wavelength and single-frequency Q-switching optical fiber laser device. The laser device comprises a saturable absorber, a high gain optical fiber, a polarization-maintaining multi-wavelength narrow-band fiber Bragg grating, a resonant cavity temperature control module, a polarization-maintaining wavelength division multiplexer, a pump source and a polarization-maintaining light isolator. By taking a highly doped phosphate optical fiber as a laser gain medium, two ends of the optical fiber device are connected with the saturable absorber and the polarization-maintaining multi-wavelength narrow-band fiber Bragg grating respectively to form a short linear laser cavity.
    Type: Application
    Filed: October 28, 2019
    Publication date: April 28, 2022
    Applicant: SOUTH CHINA UNIVERSITY OF TECHNOLOGY
    Inventors: Shanhui XU, Kunyi LI, Changsheng YANG, Qilai ZHAO, Zhouming FENG, Zhongmin YANG
  • Publication number: 20210351558
    Abstract: A tunable narrow-linewidth photo-generated microwave source based on polarization control includes a high-reflectivity fiber grating, a high-gain fiber, a low-reflectivity polarization-maintaining fiber grating, a stress adjusting device, a single-mode semiconductor pump laser, an optical wavelength division multiplexer, a polarization beam splitter, a polarization controller, an optical coupler, and a photoelectric detector. Birefringence distribution in the low-reflectivity polarization-maintaining fiber grating is controlled by adjusting a stress magnitude of the stress adjusting device to the low-reflectivity polarization fiber grating, thereby controlling a laser frequency working in different polarization modes in a resonant cavity, and a tunable narrow-linewidth photo-generated microwave source is generated by a beat-frequency technology using a dual-wavelength narrow-linewidth laser with variable frequency intervals.
    Type: Application
    Filed: October 30, 2018
    Publication date: November 11, 2021
    Applicant: SOUTH CHINA UNIVERSITY OF TECHNOLOGY
    Inventors: Shanhui XU, Qilai ZHAO, Zhitao ZHANG, Changsheng YANG, Zhouming FENG, Zhongmin YANG
  • Patent number: 10901247
    Abstract: The present invention provides a repetition frequency-tunable optical frequency comb generated by basis of optical feedback. The optical frequency comb comprises a single-frequency laser resonant cavity, a wavelength division multiplexer, a single-mode semiconductor pump light source, an optical circulator, a first optical fiber coupler, a second optical fiber coupler, a photoelectric detector, a highly-stable signal source, an error signal processing system, a laser frequency modulation device and a tunable laser-delay module. The present invention performs delay-time processing to the single-frequency laser by the tunable laser-delay module, and achieves an optical feedback by the optical circulator for injecting to the resonant cavity, generating a series of tunable laser longitudinal modes with equal frequency space.
    Type: Grant
    Filed: January 1, 2018
    Date of Patent: January 26, 2021
    Assignee: South China University of Technology
    Inventors: Shanhui Xu, Qilai Zhao, Zhongmin Yang, Zhouming Feng, Changsheng Yang
  • Publication number: 20190310498
    Abstract: The present invention provides a repetition frequency-tunable optical frequency comb generated by basis of optical feedback. The optical frequency comb comprises a single-frequency laser resonant cavity, a wavelength division multiplexer, a single-mode semiconductor pump light source, an optical circulator, a first optical fiber coupler, a second optical fiber coupler, a photoelectric detector, a highly-stable signal source, an error signal processing system, a laser frequency modulation device and a tunable laser-delay module. The present invention performs delay-time processing to the single-frequency laser by the tunable laser-delay module, and achieves an optical feedback by the optical circulator for injecting to the resonant cavity, generating a series of tunable laser longitudinal modes with equal frequency space.
    Type: Application
    Filed: January 1, 2018
    Publication date: October 10, 2019
    Inventors: Shanhui Xu, Qilai Zhao, Zhongmin Yang, Zhouming Feng, Changsheng Yang