This paper proposes a Mach Zehnder/Fabry Perot Interferometer(MZI/FPI)fiber sensor based on Single-mode Fiber(SMF)and Hollow-core Fiber(HCF),which has high sensitivity to temperature and lateral loads.The proposed dev...This paper proposes a Mach Zehnder/Fabry Perot Interferometer(MZI/FPI)fiber sensor based on Single-mode Fiber(SMF)and Hollow-core Fiber(HCF),which has high sensitivity to temperature and lateral loads.The proposed device consists of two single-mode fiber cones formed by manually controlling the fusion splicer and an air cavity formed by fusing a section of hollow-core fiber.The structure of the sensor is a double cone cascaded air cavity.At the beginning of the design,we compared the basic transmission spectra of single cone structure and double cone structure experimentally,and therefore chose to use double cone structure and air cavity cascade.Light undergoes its first reflection at the first interface between the single-mode fiber and the air cavity structure,and its second reflection at the second interface between the air cavity structure and the single-mode fiber.The two reflected light waves produced by the two reflections form FP interference,which can be used to measure lateral loads.The transmitted light is excited through the first cone,and a portion of the core mode light is excited to the cladding,while another portion of the core mode light continues to propagate in the core.The light couples at the second cone,and the cladding mode light couples back into the core,forming MZ interference with the core mode light,which can be used to measure temperature.The use of hollow-core fiber to form an air cavity has little effect on transmitted light,while avoiding the problem of crosstalk in dual parameter measurements.By designing temperature and lateral load experiments,this article verifies the sensitivity characteristics of this sensor to temperature and lateral loads.A significant redshift phenomenon was observed in the temperature experiment.A significant redshift phenomenon also occurred in the lateral load experiment.Through wavelength demodulation,the experimental results show that the wavelength sensitivity of the sensor to temperature is 56.29 pm/℃in the range of 30℃to 80℃.The wavelength sensitivity of the sensor to lateral loads is 1.123 nm/N in the range of 0~5 N.In addition,we have prepared multiple sets of fiber optic sensors with this structure and conducted repeated experiments to verify that the sensing performance of this structure of fiber optic sensors for temperature and lateral load is relatively stable.Also,the different waist diameters of cones will have a certain impact on the transmission spectrum of MZ,while the length of the air cavity will also have a certain impact on the reflection spectrum of FP.This article lists some fiber optic sensors for dual parameter measurement of temperature and lateral load.Compared with the listed sensors,the fiber optic sensor proposed in this article has better sensitivity to temperature and lateral load.And the fiber optic sensor proposed in this article has a simple manufacturing process,low production cost,and good performance,which has certain prospects in scientific research and industrial production.展开更多
碘甲烷是一种有毒的甲基化试剂和土壤消毒剂,应用十分广泛,研究其基本的物理性质和使其降解的有效措施很有必要。使用密度泛函理论(density functional theory,DFT),在B3LYP/LANL2DZ水平上研究在外电场(0～0. 04 a. u.)作用下碘甲烷分...碘甲烷是一种有毒的甲基化试剂和土壤消毒剂,应用十分广泛,研究其基本的物理性质和使其降解的有效措施很有必要。使用密度泛函理论(density functional theory,DFT),在B3LYP/LANL2DZ水平上研究在外电场(0～0. 04 a. u.)作用下碘甲烷分子的解离特性以及多种物理性质。计算结果表明,在C—I键连线Z方向上,外电场从0逐渐增加到0. 04 a. u.时,分子体系能量逐渐减小,偶极矩单调增大. HOMO-LUMO能隙EG却呈现先增大后减小的变化趋势,C—I和C—H键键长逐渐增大,更加易于裂解。在外电场逐渐增强时,解离特性表现为:CH3I分子的C—I键方向扫描得到的势能曲线的束缚状态逐渐消失,势垒逐渐变小最后消失。计算发现,强度为0. 04 a. u.的外电场足以使CH3I分子发生C—I键断裂而降解。该结果为保护环境和对碘甲烷进行电场降解提供理论依据。展开更多
基金National Natural Science Foundation of China(Nos.6207509,U2001601,61975084)the Jiangsu Provincial Key Research and Development Program(Nos.BE2022079,BE2022055-2)。
文摘This paper proposes a Mach Zehnder/Fabry Perot Interferometer(MZI/FPI)fiber sensor based on Single-mode Fiber(SMF)and Hollow-core Fiber(HCF),which has high sensitivity to temperature and lateral loads.The proposed device consists of two single-mode fiber cones formed by manually controlling the fusion splicer and an air cavity formed by fusing a section of hollow-core fiber.The structure of the sensor is a double cone cascaded air cavity.At the beginning of the design,we compared the basic transmission spectra of single cone structure and double cone structure experimentally,and therefore chose to use double cone structure and air cavity cascade.Light undergoes its first reflection at the first interface between the single-mode fiber and the air cavity structure,and its second reflection at the second interface between the air cavity structure and the single-mode fiber.The two reflected light waves produced by the two reflections form FP interference,which can be used to measure lateral loads.The transmitted light is excited through the first cone,and a portion of the core mode light is excited to the cladding,while another portion of the core mode light continues to propagate in the core.The light couples at the second cone,and the cladding mode light couples back into the core,forming MZ interference with the core mode light,which can be used to measure temperature.The use of hollow-core fiber to form an air cavity has little effect on transmitted light,while avoiding the problem of crosstalk in dual parameter measurements.By designing temperature and lateral load experiments,this article verifies the sensitivity characteristics of this sensor to temperature and lateral loads.A significant redshift phenomenon was observed in the temperature experiment.A significant redshift phenomenon also occurred in the lateral load experiment.Through wavelength demodulation,the experimental results show that the wavelength sensitivity of the sensor to temperature is 56.29 pm/℃in the range of 30℃to 80℃.The wavelength sensitivity of the sensor to lateral loads is 1.123 nm/N in the range of 0~5 N.In addition,we have prepared multiple sets of fiber optic sensors with this structure and conducted repeated experiments to verify that the sensing performance of this structure of fiber optic sensors for temperature and lateral load is relatively stable.Also,the different waist diameters of cones will have a certain impact on the transmission spectrum of MZ,while the length of the air cavity will also have a certain impact on the reflection spectrum of FP.This article lists some fiber optic sensors for dual parameter measurement of temperature and lateral load.Compared with the listed sensors,the fiber optic sensor proposed in this article has better sensitivity to temperature and lateral load.And the fiber optic sensor proposed in this article has a simple manufacturing process,low production cost,and good performance,which has certain prospects in scientific research and industrial production.
基金Supported by the National Natural Science Foundation of China(U1932149,21763027)Natural Science Foundation of Xinjiang(2017D01B36)Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(18KJA140002)
基金Supported by Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(18KJA140002)Six Talent Peaks Project in Jiangsu Province(2015-JNHB-011)+1 种基金College Students Practice Innovative Tranining Program of Nuist(201710300058Y)Undergraduate Training Program for Innovation and Entrepreneurship(201710762008,201710762055)
文摘碘甲烷是一种有毒的甲基化试剂和土壤消毒剂,应用十分广泛,研究其基本的物理性质和使其降解的有效措施很有必要。使用密度泛函理论(density functional theory,DFT),在B3LYP/LANL2DZ水平上研究在外电场(0～0. 04 a. u.)作用下碘甲烷分子的解离特性以及多种物理性质。计算结果表明,在C—I键连线Z方向上,外电场从0逐渐增加到0. 04 a. u.时,分子体系能量逐渐减小,偶极矩单调增大. HOMO-LUMO能隙EG却呈现先增大后减小的变化趋势,C—I和C—H键键长逐渐增大,更加易于裂解。在外电场逐渐增强时,解离特性表现为:CH3I分子的C—I键方向扫描得到的势能曲线的束缚状态逐渐消失,势垒逐渐变小最后消失。计算发现,强度为0. 04 a. u.的外电场足以使CH3I分子发生C—I键断裂而降解。该结果为保护环境和对碘甲烷进行电场降解提供理论依据。
