The South China University of Technology

Shanhui Xu

Zhongmin Yang

Zhouming Feng

Changsheng Yang

Qilai Zhao

Yuning Zhang

Qinyuan Zhang

Yuanfei Zhang

Zhonghong Jiang

Zhitao Zhang

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.

Tunable narrow-linewidth photo-generated microwave source based on polarization control

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. Meanwhile, in combination with the highly-stable signal source, the error signal processing system and the laser frequency modulation device, a laser frequency lock is achieved, and the laser frequency comb is generated. The invention obtains a repetition frequency-tunable laser frequency comb with a simple and practical method, having an extensive application prospect and huge application value in fields such as optical fiber sensing and spectroscopy of atom and molecule.

Optical feedback-based repetitive frequency adjustable optical frequency comb

A multi-wavelength single-frequency optical fiber laser source for a laser radar system includes a resonant cavity composed of a high-reflectivity chirped optical fiber grating, a high gain optical fiber and a low-reflectivity chirped optical fiber grating, a single-mode semiconductor pump laser served as a pump light source, an optical wavelength division multiplexer, an optical coupler, an optical isolator, an optical circulator, an optical filter module, and a semiconductor optical amplifier. The pump light source performs optical fiber core pumping with respect to the high gain optical fiber. A portion of the wide-spectrum laser is filtered by the optical filter module to obtain a wavelength corresponding to a specific central frequency. Multi-wavelength laser lasing with a narrow linewidth and single longitudinal mode is implemented by combining a short linear resonant cavity structure and the optical filter module.

Multi-wavelength narrow-linewidth single-frequency optical fiber laser source for laser radar system

A width-tunable single-frequency fiber laser light source for coherent optical orthogonal frequency division multiplexing system including a chirped fiber grating with high reflectivity, a high gain optical fiber, a chirped fiber grating with low reflectivity, a single-mode semiconductor pump laser, an optical wavelength division multiplexer, an optical coupler, an optical circulator, and a tunable optical filter module is provided. The chirped fiber grating with low reflectivity and the chirped fiber grating with high reflectivity together serve as a front cavity mirror and a back cavity mirror of a resonant cavity to realize laser oscillation. After a laser with broad spectrum output from the optical wavelength division multiplexer is split by the optical coupler, a part of the laser passes through the optical circulator to enter the tunable optical filter module. A wavelength corresponding to any nominal center frequency stipulated by the ITU-T is selected by the tunable optical filter module, with a 3 dB spectral width of less than 0.1 nm, and is then injected back into the resonant cavity via the optical circulator and the optical coupler, and the resonant cavity is subjected to a self-injection locking.

Width-tunable single-frequency fiber laser light source for coherent optical orthogonal frequency division multiplexing system

A tunable narrow-linewidth single-frequency linear-polarization laser device comprising a heat sink, a pumping source packaged on the heat sink, a first and second collimating lenses, a laser back cavity mirror, a thermal optical tunable filter, a rare-earth-ion heavily-doped multicomponent glass optical fiber, a super-structure polarization-maintaining fiber grating, a polarization-maintaining optical isolator, a polarization-maintaining optical fiber, and a thermoelectric refrigerating machine. The laser device uses a short and straight single-frequency resonant cavity structure, the heavily-doped and high-gain characteristics of the multicomponent glass optical fiber, a frequency selection role and wavelength tuning function of the thermal optical tunable filter and the superstructure polarization-maintaining fiber grating, and combines a precision temperature adjustment technology, and by means of real-time adjustment of distribution of reflection wavelengths and transmission wavelengths, the laser device changes spectrum peak overlapping positions, so as to implement stable output of wide-tuning-range, extra-narrow-linewidth, high-extinction-ratio and high-output-power continuously tunable single-frequency linear-polarization laser.

Growing community of inventors

Guangzhou, China

Shanhui Xu