Environmental vibration causes mechanical deformation in optical fibers, which induces excess frequency noise in fiber-stabilized lasers. In order to solve such a problem, we propose an ultralow acceleration sensitivi...Environmental vibration causes mechanical deformation in optical fibers, which induces excess frequency noise in fiber-stabilized lasers. In order to solve such a problem, we propose an ultralow acceleration sensitivity fiber spool with symmetrically mounted structure. By numerical analysis with the finite element method, we obtain the optimal geometry parameters of the spool with which the horizontal and vertical acceleration sensitivity can be reduced to 3.25 × 10^-12/g and 5.38 × 10^-12/g respectively. Moreover, the structure features the insensitivity to the variation of geometry parameters,which will minimize the influence from numerical simulation error and manufacture tolerance.展开更多
To improve the sensitivity measurement of temperature sensors,a fiber optic temperature sensor structure based on the harmonic Vernier effect with two parallel fiber Sagnac interferometers(FSIs)is designed,and theoret...To improve the sensitivity measurement of temperature sensors,a fiber optic temperature sensor structure based on the harmonic Vernier effect with two parallel fiber Sagnac interferometers(FSIs)is designed,and theoretical analysis and experimental testing are conducted.The FSI consisting of two polarization maintaining fibers(PMFs)with lengths of 13.62 m and 15.05 m respectively is used to achieve the basic Vernier effect.Then by changing the length of one PMF to approximately i times that of the others,the FSI composed of two PMFs of 7.1 m and 15.05 m is used to achieve the first-order harmonic Vernier effect.Afterward,temperature sensing tests are conducted to observe the wavelength drift during temperature changes and ultimately achieve high sensitivity.The experimental results show that the temperature sensitivity of the sensor based on the first-order harmonic Vernier effect is-28.89 nm/℃,which is 17.09 times that of a single FSI structure(-1.69 nm/℃)and 1.84 times that of the sensitivity generated by the structure based on the basic Vernier effect(-15.69 nm/℃).The experimental results are consistent with the theoretical analysis.The structure proposed in this paper achieves drift measurement of 0.1℃ variation based on 1 drift,making the fiber optic temperature sensor applicable to related fields that requir e high precision temperature.The proposed temperature sensor has the simple structure,low production cost,high sensitivity,and broad application prospects.展开更多
A brief review of recent progress made in a range of in-fiber integrated interferometers for measuring is presented,with particular attention paid to the multi-core based in-fiber integrated techniques,which have the ...A brief review of recent progress made in a range of in-fiber integrated interferometers for measuring is presented,with particular attention paid to the multi-core based in-fiber integrated techniques,which have the potential to be exploited in a variety of wide applications.展开更多
In the field of oil well logging, real-time monitoring of the fluid flow parameter provides a scientific basis for oil and gas optimization exploration and increase in reservoir recovery, so a non-intrusive flow test ...In the field of oil well logging, real-time monitoring of the fluid flow parameter provides a scientific basis for oil and gas optimization exploration and increase in reservoir recovery, so a non-intrusive flow test method based on turbulent vibration was proposed. The specific length of the sensor fiber wound tightly around the outer wall of the pipe was connected with the optical fiber gratings at both ends, and the sensor fiber and the optical fiber gratings composed the flow sensing unit. The dynamic pressure was generated by the turbulence when fluid flows through the pipe, and the dynamic pressure resulted in the light phase shift of the sensor fiber. The phase information was demodulated by the fiber optic interferometer technology, time division multiplexing technology, and phase generated carrier modulation and demodulation techniques. The quadratic curve relationship between the phase change and flow rate was found by experimental data analysis, and the experiment confirmed the feasibility of the optical fiber flow test method with non-intrusion and achieved the real-time monitoring of the fluid flow.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11034008 and 11274324)the Key Research Program of the Chinese Academy of Sciences(Grant No.KJZD-EW-W02)
文摘Environmental vibration causes mechanical deformation in optical fibers, which induces excess frequency noise in fiber-stabilized lasers. In order to solve such a problem, we propose an ultralow acceleration sensitivity fiber spool with symmetrically mounted structure. By numerical analysis with the finite element method, we obtain the optimal geometry parameters of the spool with which the horizontal and vertical acceleration sensitivity can be reduced to 3.25 × 10^-12/g and 5.38 × 10^-12/g respectively. Moreover, the structure features the insensitivity to the variation of geometry parameters,which will minimize the influence from numerical simulation error and manufacture tolerance.
基金supported by the Primary Research and Development Plan of Zhejiang Province,China(Grant No.2023C03014)the Key Research and Development Program of Zhejiang Province,China(Grant No.2022C03037).
文摘To improve the sensitivity measurement of temperature sensors,a fiber optic temperature sensor structure based on the harmonic Vernier effect with two parallel fiber Sagnac interferometers(FSIs)is designed,and theoretical analysis and experimental testing are conducted.The FSI consisting of two polarization maintaining fibers(PMFs)with lengths of 13.62 m and 15.05 m respectively is used to achieve the basic Vernier effect.Then by changing the length of one PMF to approximately i times that of the others,the FSI composed of two PMFs of 7.1 m and 15.05 m is used to achieve the first-order harmonic Vernier effect.Afterward,temperature sensing tests are conducted to observe the wavelength drift during temperature changes and ultimately achieve high sensitivity.The experimental results show that the temperature sensitivity of the sensor based on the first-order harmonic Vernier effect is-28.89 nm/℃,which is 17.09 times that of a single FSI structure(-1.69 nm/℃)and 1.84 times that of the sensitivity generated by the structure based on the basic Vernier effect(-15.69 nm/℃).The experimental results are consistent with the theoretical analysis.The structure proposed in this paper achieves drift measurement of 0.1℃ variation based on 1 drift,making the fiber optic temperature sensor applicable to related fields that requir e high precision temperature.The proposed temperature sensor has the simple structure,low production cost,high sensitivity,and broad application prospects.
基金This work was partially supported by the National Nature Science Foundation of China,under grant number 60877046,60707013 and 60807032,to the Harbin Engineering University.
文摘A brief review of recent progress made in a range of in-fiber integrated interferometers for measuring is presented,with particular attention paid to the multi-core based in-fiber integrated techniques,which have the potential to be exploited in a variety of wide applications.
文摘In the field of oil well logging, real-time monitoring of the fluid flow parameter provides a scientific basis for oil and gas optimization exploration and increase in reservoir recovery, so a non-intrusive flow test method based on turbulent vibration was proposed. The specific length of the sensor fiber wound tightly around the outer wall of the pipe was connected with the optical fiber gratings at both ends, and the sensor fiber and the optical fiber gratings composed the flow sensing unit. The dynamic pressure was generated by the turbulence when fluid flows through the pipe, and the dynamic pressure resulted in the light phase shift of the sensor fiber. The phase information was demodulated by the fiber optic interferometer technology, time division multiplexing technology, and phase generated carrier modulation and demodulation techniques. The quadratic curve relationship between the phase change and flow rate was found by experimental data analysis, and the experiment confirmed the feasibility of the optical fiber flow test method with non-intrusion and achieved the real-time monitoring of the fluid flow.
