Aiming at the self-diagnosis and self-healing problems of composite materials, inspired by the self-healing mechanism of organisms, this paper proposes a damage self-healing method for composite structures based on bionic optical fiber. The paper introduces the designed structure and material composition of the bionic optical fiber, and the self-healing principle of the bionic optical fiber-composite structure. Finally, the three-point bending method is used to conduct damage self-healing experimental research on the composite material, and the influence of the embedding of the bionic optical fiber on the structural properties of the composite material is also analyzed. The repaired images of the composite structure obtained by the microscope can be seen that the physical structure repair is well. Moreover, the damage self-healing experimental results show that the self-repair efficiency of the flexural properties of the composite structure is 65.05%. The proposal of bionic optical fiber has important significance and practical application value for the research on the damage self-healing of composite materials. 

A damage self-healing method of composite structures based on bionic optical fiber

Fiber-optic sensing scheme based on high-order Stimulated Brillouin scattering in a fiber ring and frequency down-conversion

In this paper, a temperature sensing scheme realized with Sagnac interferometer (SI) based microwave photonic filter (MPF) has been proposed and experimentally demonstrated. In our experiment, the sensitivities of -1.6 MHz/°C and -1.29 MHz/°C have been achieved by using SI with the length of polarization maintaining fiber (PMF) of 7.3 m and 5.3 m acting as the sensing fiber, respectively. The proposed sensing scheme converts the wavelength spacing changes of the SI to the frequency shifts of the MPF’s passband, and thus has an unlimited measurement range.

A Temperature Sensing Scheme Realized with Sagnac Interferometer Based Microwave Photonic Filter

The invention provides a refractive index sensing measurement device and method. The device comprises a corrosion Bragg fiber grating FP interferometer, a matching Bragg fiber grating, an optical amplifier, an optical fiber circulator, an optical fiber coupler, a photoelectric detector and a frequency spectrograph, an optical signal sent by the optical amplifier is input into the optical fiber circulator and the matching Bragg fiber grating; the narrow-band transmission peak wavelength of the corrosion Bragg fiber grating FP interferometer is reflected through the matching Bragg fiber grating;the reflected narrow-band transmission peak wavelength is transmitted to the optical fiber coupler to form laser; the laser is output through the optical fiber coupler, frequency beating is conductedon the laser through the photoelectric detector to generate microwave signal frequency, and the microwave signal frequency is measured through a frequency spectrograph so that the refractive index ofa solution to be measured can be obtained according to the microwave signal frequency and a pre-drawn relation curve, and therefore, the sensitivity and resolution of sensing are greatly improved.

Refractive index sensing measurement device and method

The invention provides a continuous millimeter wave signal generation device and method. The device comprises an optical fiber coupler, and a semiconductor optical amplifier, a first polarization controller, a polarization-maintaining phase shift Bragg fiber grating, a second polarization controller, a first optical fiber circulator, a matched polarization-maintaining Bragg fiber grating, a secondoptical fiber circulator and a non-pumped polarization-maintaining erbium-doped optical fiber which are arranged in a laser resonant cavity. An optical signal emitted by the semiconductor optical amplifier is input to the polarization-maintaining phase shift Bragg fiber grating through the first polarization controller, by matching with the polarization-maintaining fiber bragg grating to reflect,two narrow-band wavelengths are obtained, the single-longitudinal-mode dual-wavelength laser is formed through the polarization-maintaining erbium-doped optical fiber, and the laser is transmitted tothe optical fiber coupler, and the single-longitudinal-mode dual-wavelength laser is coupled and output to a photoelectric detector through the first output end of the optical fiber coupler so as togenerate the continuous millimeter wave signals, so that high-frequency millimeter wave signals can be generated conveniently, the structure is simple, and the cost is low.

Cai Xun

Papers

Fiber-optic sensing scheme based on high-order Stimulated Brillouin scattering in a fiber ring and frequency down-conversion

A Temperature Sensing Scheme Realized with Sagnac Interferometer Based Microwave Photonic Filter

Refractive index sensing measurement device and method

Continuous millimeter wave signal generating device and method