An ultrasonic sensitivity-improved fiber-optic Fabry-Perot interferometer （FPI） is proposed and employed for ultra- sonic imaging of seismic physical models （SPMs）. The FPI comprises a flexible ultra-thin gold fil...An ultrasonic sensitivity-improved fiber-optic Fabry-Perot interferometer （FPI） is proposed and employed for ultra- sonic imaging of seismic physical models （SPMs）. The FPI comprises a flexible ultra-thin gold film and the end face of a graded-index multimode fiber （MMF）, both of which are enclosed in a ceramic tube. The MMF in a specified length can collimate the diverged light beam and compensate for the light loss inside the air cavity, leading to an increased spectral fringe visibility and thus a steeper spectral slope. By using the spectral sideband filtering technique, the collimated FP1 shows an improved ultrasonic response. Moreover, two-dimensional images of two SPMs are achieved in air by recon- structing the pulse-echo signals through using the time-of-flight approach. The proposed sensor with easy fabrication and compact size can be a good candidate for high-sensitivity and high-precision nondestructive testing of SPMs.展开更多
A compact and highly sensitive gas pressure and temperature sensor based on Fabry-Pérot interferometer(FPI)and fiber Bragg grating(FBG)is proposed and demonstrated experimentally in this paper.The theoretical mod...A compact and highly sensitive gas pressure and temperature sensor based on Fabry-Pérot interferometer(FPI)and fiber Bragg grating(FBG)is proposed and demonstrated experimentally in this paper.The theoretical model for pressure and temperature sensing is established.Building on this foundation,a novel micro silicon cavity sensor structure sensitive to pressure is devised downstream of an FBG.The concept of separate measurement and the mechanisms enhancing pressure sensitivity are meticulously analyzed,and the corresponding samples are fabricated.The experimental results indicate that the pressure sensitivity of the sensor is-747.849 nm/MPa in 0—100 k Pa and its linearity is 99.7%and it maintains good stability in 150 min.The sensor offers the advantages of compact size,robust construction,easy fabrication,and high sensitivity,making it potentially valuable for micro-pressure application.展开更多
The paper presents a number of signal processing approaches for the spectral interferometric interrogation of extrinsic Fabry-Perot interferometers(EFPIs). The analysis of attainable microdisplacement resolution is pe...The paper presents a number of signal processing approaches for the spectral interferometric interrogation of extrinsic Fabry-Perot interferometers(EFPIs). The analysis of attainable microdisplacement resolution is performed and the analytical equations describing the dependence of resolution on parameters of the interrogation setup are derived. The efficiency of the proposed signal processing approaches and the validity of analytical derivations are supported by experiments. The proposed approaches allow the interrogation of up to four multiplexed sensors with attained resolution between 30 pm and 80 pm, up to three times improvement of microdisplacement resolution of a single sensor by means of using the reference interferometer and noisecompensating approach, and ability to register signals with frequencies up to 1 kHz in the case of 1 Hz spectrum acquisition rate. The proposed approaches can be used for various applications, including biomedical, industrial inspection, and others, amongst the microdisplacement measurement.展开更多
Periodic resistance oscillations in Fabry-Perot quantum Hall interferometers are observed at integer filling factors of the constrictions, fc=1, 2, 3, 4, 5 and 6. Rather than the Aharonov-Bohm interference, these osci...Periodic resistance oscillations in Fabry-Perot quantum Hall interferometers are observed at integer filling factors of the constrictions, fc=1, 2, 3, 4, 5 and 6. Rather than the Aharonov-Bohm interference, these oscillations are attributed to the Coulomb interactions between interfering edge states and localized states in the central island of an interferometer, as confirmed by the observation of a positive slope for the lines of constant oscillation phase in the image plot of resistance in the 13 Vs plane. Similar resistance oscillations are also observed when the area A of the center regime and the backseattering probability of interfering edge states are varied, by changing the side-gate voltages and the configuration of the quantum point contacts, respectively. The oscillation amplitudes decay exponentially with temperature in the ramge of 40mK〈 T ≤ 130 mK, with a characteristic temperature T0 -25 mK, consistent with recent theoretical and experimental works.展开更多
Fiber Bragg grating Fabry-Perot (FBG F-P) cavity is used as the sensing model to measure the refractive index of the liquid solution. The cladding of the fiber, which is used as the F-P cavity, is etched by HF solutio...Fiber Bragg grating Fabry-Perot (FBG F-P) cavity is used as the sensing model to measure the refractive index of the liquid solution. The cladding of the fiber, which is used as the F-P cavity, is etched by HF solution to enhance the sensitivity to the external refractive index. The experimental results show that with the concentration change of the external solution, the effective refractive index of etched fiber will change, thus the spectra of FBG F-P cavity will appear a spilt point. The relationship be...展开更多
To achieve high quality factor and high-sensitivity refractive index sensor,a slot micro-ring resonator(MRR)based on asymmetric Fabry-Perot(FP)cavity was proposed.The structure consisted of a pair of elliptical holes ...To achieve high quality factor and high-sensitivity refractive index sensor,a slot micro-ring resonator(MRR)based on asymmetric Fabry-Perot(FP)cavity was proposed.The structure consisted of a pair of elliptical holes to form an FP cavity and a microring resonator.The two different optical modes generated by the micro-ring resonator were destructively interfered to form a Fano line shape,which improved the system sensitivity while obtaining a higher quality factor and extinction ratio.The transmission principle of the structure was analyzed by the transfer matrix method.The transmission spectrum and mode field distribution of the proposed structure were simulated by the finite difference time domain(FDTD)method,and the key structural parameters affecting the Fano line shape in the device were optimized.The simulation results show that the quality factor of the device reached 22037.1,and the extinction ratio was 23.9 dB.By analyzing the refractive index sensing characteristics,the sensitivity of the structure was 354 nm·RIU−1,and the detection limit of the sensitivity was 2×10−4 RIU.Thus,the proposed compact asymmetric FP cavity slot micro-ring resonator has obvious advantages in sensing applications owing to its excellent performance.展开更多
A surface plasmon interference lithography assisted by a Fabry-Perot （F-P） cavity composed of subwavelength metal gratings and a thin metal fihn is proposed to fabricate high-quality nanopatterns. The calculated res...A surface plasmon interference lithography assisted by a Fabry-Perot （F-P） cavity composed of subwavelength metal gratings and a thin metal fihn is proposed to fabricate high-quality nanopatterns. The calculated results indicate that uniform straight interference fringes with high contrast and high electric-field intensity are formed in the resist under the F-P cavity. The analyses of spatial frequency spectra illuminate the physical mechanism of the formation for the interference fringes. The influence of the F-P cavity spacing is discussed in detail. Moreover, the error analyses reveal that all parameters except the metal grating period in this scheme can bear large tolerances for the device fabrication.展开更多
We demonstrate a fiber Fabry-Pérot cavity in the ultraviolet range, which covers the florescence wavelength for the <sup>2</sup>P to <sup>2</sup>S transition of Yb and is designed in the b...We demonstrate a fiber Fabry-Pérot cavity in the ultraviolet range, which covers the florescence wavelength for the <sup>2</sup>P to <sup>2</sup>S transition of Yb and is designed in the bad cavity limit for florescence collection. Benefiting from both the small cavity mode volume and the large atom dipole, a cavity with moderate finesse and high transmission still supports a good cooperativity, which is made and tested in experiment. Based on the measured experimental parameters, simulation performed on the cavity and ion shows a Purcell factor better than 2.5 and a single-mode fiber collection efficiency over 10%. This technology can support ultra-bright single photon sources based on trapped ions and can provide the possibility to link remote atoms as a quantum network.展开更多
The circular phased antenna array is commonly used for generating waves bearing Orbital Angular Momentum (OAM) in the radio frequency band, but it achieves a relatively low directivity. To overcome this drawback, we p...The circular phased antenna array is commonly used for generating waves bearing Orbital Angular Momentum (OAM) in the radio frequency band, but it achieves a relatively low directivity. To overcome this drawback, we present here a method to improve the directivity of an OAM circular phased antenna array by embedding it inside a Fabry-Perot cavity. The Fabry-Perot cavity contains three main parts: a partially reflecting surface (PRS), an air cavity and a ground plane. Simulation data show that the directivity of this new OAM antenna achieves an improvement of 8.2 dB over the original array. A prototype is realized and characterized. The simulated and measured characteristics are in good agreement.展开更多
A metal-sensitive diaphragm fiber optic pressure sensor with temperature compensation is developed for pressure monitoring in high-temperature environments,such as engine fuel systems,oil and gas wells,and aviation hy...A metal-sensitive diaphragm fiber optic pressure sensor with temperature compensation is developed for pressure monitoring in high-temperature environments,such as engine fuel systems,oil and gas wells,and aviation hydraulic systems.The sensor combines a metal-sensitive diaphragm and a sapphire wafer to form a temperature-pressure dual Fabry-Perot(FP)interference cavity.A cross-correlation signal demodulation algorithm and a temperature decoupling method are utilized to reduce the influence of temperature crosstalk on pressure measurement.Experimental results show that the maximum nonlinear error of the sensor pressure measurement is 0.75%full scale(FS)and 0.99%FS at room temperature and 300°C,respectively,in a pressure range of 0−10 MPa and 0−1.5 MPa.The sensor’s pressure measurement accuracy is 1.7%FS when using the temperature decoupling method.The sensor exhibits good static pressure characteristics,stability,and reliability,providing an effective solution for high-temperature pressure monitoring applications.展开更多
Marine monitoring faces significant challenges due to the vast spatial scale and subtle variations in environmental parameters,necessitating distributed sensor systems with exceptional sensitivity and multiplexing cap...Marine monitoring faces significant challenges due to the vast spatial scale and subtle variations in environmental parameters,necessitating distributed sensor systems with exceptional sensitivity and multiplexing capabilities.While existing high-sensitivity fiber optic sensors lack sufficient multiplexing capacity for large-scale deployment,we present a novel distributed sensing scheme integrating Fabry-Perot interferometers(FPIs)with draw-tower gratings(DTGs).Each FPI is constructed through two adjacent DTGs interconnected via functionalized sensing fibers with distinct coating materials to decouple the mutual cross-sensitivity between temperature and pressure.Through mechanical capsulation with a pressure-sensitive copper tube,hydrostatic pressure-induced deformation creates measurable axial strain gradients in the optical fiber,achieving enhanced depth sensitivity.The experimental results show that the sensor exhibits good linear responses(R^(2)>0.99)across tested parameter ranges,with measured temperature and depth sensitivities of12,784 rad/℃and 801 rad/m,respectively,consistent with theoretical models.The system achieves remarkable resolution of 1.56×10^(-5)℃(temperature)and 2.50×10^(-4)m(depth)through phase-sensitive detection.Leveraging the ultra-weak reflectivity of DTGs and the compatibility of the sensing array with the Michelson interferometer(MI),the sensing structure exhibits excellent multiplexing capability.With advantages of high sensitivity,unprecedented resolution,and ease of multiplexing,the structure possesses significant potential as an efficient solution for distributed measurements in marine engineering.展开更多
An optical fiber dual Fabry-Perot interferometric carbon monoxide gas sensor based on PANI/Co3 O4/GO(PCG)sensing membrane coated on the end face of the optical fiber is proposed and fabricated.One end face of photonic...An optical fiber dual Fabry-Perot interferometric carbon monoxide gas sensor based on PANI/Co3 O4/GO(PCG)sensing membrane coated on the end face of the optical fiber is proposed and fabricated.One end face of photonic crystal fiber(PCF)without cut-off wavelength is fused with a single-mode fiber(SMF),and the other end face of the PCF is coated with PCG sensing membrane.The collapsed layer formed during the air hole fusion of PCF is used as the first reflector,the interface between PCF and sensing membrane is used as the second reflector,and the interface between the sensing membrane and the air is used as the third reflector,thus the dual Fabry-Pe rot structure sensor is formed.The results show that the sensor has excellent sensitivity and selectivity to carbon monoxide.With the increasing concentration of carbon monoxide gas in the range of 0-60 ppm,the intensity of interference spectrum decreases.The sensitivity of the sensor is 0.3473 dB m/ppm,and its linearity is good.The response time and recovery time are 68 s and 106 s,respectively.The sensor has the advantages of the compact size,low cost,high sensitivity,strong selectivity and simple structure.It is suitable for the sensing detection of low concentration carbon monoxide gas.展开更多
The extinction ratio and insertion loss of spatial light modulator are subject to the material problem, thus limiting its applications. One reflection-type silicon-based spatial light modulator with high reflective ma...The extinction ratio and insertion loss of spatial light modulator are subject to the material problem, thus limiting its applications. One reflection-type silicon-based spatial light modulator with high reflective materials outside the Fabry-Perot cavity is demonstrated in this paper. The reflectivity values of the outside-cavity materials with different film layer numbers are simulated. The reflectivity values of 6-pair Ta2O5/SiO2 films at 1550 nm are experimentally verified to be as high as 99.9%. The surfaces of 6-pair Ta2O5/SiO2 films are smooth: their root-mean-square roughness values are as small as 0.53 nm. The insertion loss of the device at 1550 nm is only 1.2 dB. The high extinction ratio of the device at 1550 nm and 11 V is achieved to be 29.7 dB. The spatial light modulator has a high extinction ratio and low insertion loss for applications.展开更多
The birefringence optical feedback with a folded cavity in HeNe laser is investigated.A theory model based on the equivalent cavity of the Fabry–Perot interferometer is presented.The phase difference between the two ...The birefringence optical feedback with a folded cavity in HeNe laser is investigated.A theory model based on the equivalent cavity of the Fabry–Perot interferometer is presented.The phase difference between the two intensities in birefringence feedback is twice the retardation of the wave plate.The phase difference is invariable when the length of the feedback cavity changes.With the adoption of a cube corner prism(CCP)to form a folded cavity,the fringe frequency is doubled,and the resolution of the displacement sensor based on birefringence optical feedback with a folded cavity is improved.A resistance chain of 5-fold subdivision and 4-fold logic subdivision is used as further subdivision.The resolution ofλ/80 is obtained eventually;for 632.8 nm HeNe laser it is 7.91 nm.The displacement sensor based on birefringence optical feedback with a folded cavity is simple and of high resolution,large measurement range,low cost,and is of great application potential in industry.展开更多
Based on dual-differential comparing principle, an experimental system of optical fiber F-P interferometric micro-displacement measurement is introduced. It is capable of achieving the absolute displacement measuremen...Based on dual-differential comparing principle, an experimental system of optical fiber F-P interferometric micro-displacement measurement is introduced. It is capable of achieving the absolute displacement measurement, and wavelet transforms is adopted as theory fundament to extract the optical F-P interferometric characteristic signal and remove the noise, so its resolution can reach 0. 01 μm in the dynamic range of 0～ 1 mm.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61735014,61327012,and 61275088)the Scientific Research Program Funded by Shaanxi Provincial Education Department,China(Grant No.08JZ58)the Northwest University Graduate Innovation and Creativity Funds,China(Grant No.YZZ17088)
文摘An ultrasonic sensitivity-improved fiber-optic Fabry-Perot interferometer （FPI） is proposed and employed for ultra- sonic imaging of seismic physical models （SPMs）. The FPI comprises a flexible ultra-thin gold film and the end face of a graded-index multimode fiber （MMF）, both of which are enclosed in a ceramic tube. The MMF in a specified length can collimate the diverged light beam and compensate for the light loss inside the air cavity, leading to an increased spectral fringe visibility and thus a steeper spectral slope. By using the spectral sideband filtering technique, the collimated FP1 shows an improved ultrasonic response. Moreover, two-dimensional images of two SPMs are achieved in air by recon- structing the pulse-echo signals through using the time-of-flight approach. The proposed sensor with easy fabrication and compact size can be a good candidate for high-sensitivity and high-precision nondestructive testing of SPMs.
基金supported in part by the National Natural Science Foundation of China(Nos.61735014 and 61927812)the Shaanxi Provincial Education Department(No.18JS093)+2 种基金the Natural Science Basic Research Program of Shaanxi Province(No.2024JC-YBMS-530)the Operation Fund of Logging Key Laboratory of Group Company(No.2021DQ0107-11)the Graduate Student Innovation Fund of Xi’an Shiyou University(No.YCS23213193)。
文摘A compact and highly sensitive gas pressure and temperature sensor based on Fabry-Pérot interferometer(FPI)and fiber Bragg grating(FBG)is proposed and demonstrated experimentally in this paper.The theoretical model for pressure and temperature sensing is established.Building on this foundation,a novel micro silicon cavity sensor structure sensitive to pressure is devised downstream of an FBG.The concept of separate measurement and the mechanisms enhancing pressure sensitivity are meticulously analyzed,and the corresponding samples are fabricated.The experimental results indicate that the pressure sensitivity of the sensor is-747.849 nm/MPa in 0—100 k Pa and its linearity is 99.7%and it maintains good stability in 150 min.The sensor offers the advantages of compact size,robust construction,easy fabrication,and high sensitivity,making it potentially valuable for micro-pressure application.
文摘The paper presents a number of signal processing approaches for the spectral interferometric interrogation of extrinsic Fabry-Perot interferometers(EFPIs). The analysis of attainable microdisplacement resolution is performed and the analytical equations describing the dependence of resolution on parameters of the interrogation setup are derived. The efficiency of the proposed signal processing approaches and the validity of analytical derivations are supported by experiments. The proposed approaches allow the interrogation of up to four multiplexed sensors with attained resolution between 30 pm and 80 pm, up to three times improvement of microdisplacement resolution of a single sensor by means of using the reference interferometer and noisecompensating approach, and ability to register signals with frequencies up to 1 kHz in the case of 1 Hz spectrum acquisition rate. The proposed approaches can be used for various applications, including biomedical, industrial inspection, and others, amongst the microdisplacement measurement.
基金Supported by the National Basic Research Program of China under Grant No 2014CB920904the National Natural Science Foundation of China under Grant No 91221203the Strategic Priority Research Program B of the Chinese Academy of Sciences under Grant No XDB07010200
文摘Periodic resistance oscillations in Fabry-Perot quantum Hall interferometers are observed at integer filling factors of the constrictions, fc=1, 2, 3, 4, 5 and 6. Rather than the Aharonov-Bohm interference, these oscillations are attributed to the Coulomb interactions between interfering edge states and localized states in the central island of an interferometer, as confirmed by the observation of a positive slope for the lines of constant oscillation phase in the image plot of resistance in the 13 Vs plane. Similar resistance oscillations are also observed when the area A of the center regime and the backseattering probability of interfering edge states are varied, by changing the side-gate voltages and the configuration of the quantum point contacts, respectively. The oscillation amplitudes decay exponentially with temperature in the ramge of 40mK〈 T ≤ 130 mK, with a characteristic temperature T0 -25 mK, consistent with recent theoretical and experimental works.
基金supported by the National Nature Scien- ce Foundation of China (Grant No.60672015).
文摘Fiber Bragg grating Fabry-Perot (FBG F-P) cavity is used as the sensing model to measure the refractive index of the liquid solution. The cladding of the fiber, which is used as the F-P cavity, is etched by HF solution to enhance the sensitivity to the external refractive index. The experimental results show that with the concentration change of the external solution, the effective refractive index of etched fiber will change, thus the spectra of FBG F-P cavity will appear a spilt point. The relationship be...
基金supported by Natural Science Foundation of Gansu Province(No.22JR5RA320).
文摘To achieve high quality factor and high-sensitivity refractive index sensor,a slot micro-ring resonator(MRR)based on asymmetric Fabry-Perot(FP)cavity was proposed.The structure consisted of a pair of elliptical holes to form an FP cavity and a microring resonator.The two different optical modes generated by the micro-ring resonator were destructively interfered to form a Fano line shape,which improved the system sensitivity while obtaining a higher quality factor and extinction ratio.The transmission principle of the structure was analyzed by the transfer matrix method.The transmission spectrum and mode field distribution of the proposed structure were simulated by the finite difference time domain(FDTD)method,and the key structural parameters affecting the Fano line shape in the device were optimized.The simulation results show that the quality factor of the device reached 22037.1,and the extinction ratio was 23.9 dB.By analyzing the refractive index sensing characteristics,the sensitivity of the structure was 354 nm·RIU−1,and the detection limit of the sensitivity was 2×10−4 RIU.Thus,the proposed compact asymmetric FP cavity slot micro-ring resonator has obvious advantages in sensing applications owing to its excellent performance.
基金Supported by the Natural Science Foundation of Hebei Province under Grant Nos A2013402069 and A2013402081
文摘A surface plasmon interference lithography assisted by a Fabry-Perot （F-P） cavity composed of subwavelength metal gratings and a thin metal fihn is proposed to fabricate high-quality nanopatterns. The calculated results indicate that uniform straight interference fringes with high contrast and high electric-field intensity are formed in the resist under the F-P cavity. The analyses of spatial frequency spectra illuminate the physical mechanism of the formation for the interference fringes. The influence of the F-P cavity spacing is discussed in detail. Moreover, the error analyses reveal that all parameters except the metal grating period in this scheme can bear large tolerances for the device fabrication.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11274289,11325419,11474267,11404319,61327901,61225025 and 1147426the Fundamental Research Funds for the Central Universities under Grant Nos WK2470000018 and WK2030020019+2 种基金the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant No XDB01030300the National Youth Top Talent Support Program of National High-level Personnel of Special Support Program under Grant No BB2470000005the Anhui Provincial Natural Science Foundation under Grant No 1608085QA22
文摘We demonstrate a fiber Fabry-Pérot cavity in the ultraviolet range, which covers the florescence wavelength for the <sup>2</sup>P to <sup>2</sup>S transition of Yb and is designed in the bad cavity limit for florescence collection. Benefiting from both the small cavity mode volume and the large atom dipole, a cavity with moderate finesse and high transmission still supports a good cooperativity, which is made and tested in experiment. Based on the measured experimental parameters, simulation performed on the cavity and ion shows a Purcell factor better than 2.5 and a single-mode fiber collection efficiency over 10%. This technology can support ultra-bright single photon sources based on trapped ions and can provide the possibility to link remote atoms as a quantum network.
文摘The circular phased antenna array is commonly used for generating waves bearing Orbital Angular Momentum (OAM) in the radio frequency band, but it achieves a relatively low directivity. To overcome this drawback, we present here a method to improve the directivity of an OAM circular phased antenna array by embedding it inside a Fabry-Perot cavity. The Fabry-Perot cavity contains three main parts: a partially reflecting surface (PRS), an air cavity and a ground plane. Simulation data show that the directivity of this new OAM antenna achieves an improvement of 8.2 dB over the original array. A prototype is realized and characterized. The simulated and measured characteristics are in good agreement.
文摘A metal-sensitive diaphragm fiber optic pressure sensor with temperature compensation is developed for pressure monitoring in high-temperature environments,such as engine fuel systems,oil and gas wells,and aviation hydraulic systems.The sensor combines a metal-sensitive diaphragm and a sapphire wafer to form a temperature-pressure dual Fabry-Perot(FP)interference cavity.A cross-correlation signal demodulation algorithm and a temperature decoupling method are utilized to reduce the influence of temperature crosstalk on pressure measurement.Experimental results show that the maximum nonlinear error of the sensor pressure measurement is 0.75%full scale(FS)and 0.99%FS at room temperature and 300°C,respectively,in a pressure range of 0−10 MPa and 0−1.5 MPa.The sensor’s pressure measurement accuracy is 1.7%FS when using the temperature decoupling method.The sensor exhibits good static pressure characteristics,stability,and reliability,providing an effective solution for high-temperature pressure monitoring applications.
基金supported by the National Natural Science Foundation of China(Nos.62275204 and 52071245)the Key Research and Development Program of Hubei Province(No.2023DJC170)。
文摘Marine monitoring faces significant challenges due to the vast spatial scale and subtle variations in environmental parameters,necessitating distributed sensor systems with exceptional sensitivity and multiplexing capabilities.While existing high-sensitivity fiber optic sensors lack sufficient multiplexing capacity for large-scale deployment,we present a novel distributed sensing scheme integrating Fabry-Perot interferometers(FPIs)with draw-tower gratings(DTGs).Each FPI is constructed through two adjacent DTGs interconnected via functionalized sensing fibers with distinct coating materials to decouple the mutual cross-sensitivity between temperature and pressure.Through mechanical capsulation with a pressure-sensitive copper tube,hydrostatic pressure-induced deformation creates measurable axial strain gradients in the optical fiber,achieving enhanced depth sensitivity.The experimental results show that the sensor exhibits good linear responses(R^(2)>0.99)across tested parameter ranges,with measured temperature and depth sensitivities of12,784 rad/℃and 801 rad/m,respectively,consistent with theoretical models.The system achieves remarkable resolution of 1.56×10^(-5)℃(temperature)and 2.50×10^(-4)m(depth)through phase-sensitive detection.Leveraging the ultra-weak reflectivity of DTGs and the compatibility of the sensing array with the Michelson interferometer(MI),the sensing structure exhibits excellent multiplexing capability.With advantages of high sensitivity,unprecedented resolution,and ease of multiplexing,the structure possesses significant potential as an efficient solution for distributed measurements in marine engineering.
基金supported by the National Natural Science Foundation of China(No.51574054)the University Innovation Team Building Program of Chongqing(No.CXTDX201601030)+2 种基金Scientific and Technological Research Program of Chongqing Municipal Education Commission(No.KJZD-M201901102)Chongqing Science and Technology Bureau(Nos.cstc2017shmsA20017,cstc2018jcyjAX0294,CSTCCXLJRC 201905)the Innovation Leader Project of Chongqing Science and Technology Bureau(No.CSTCCXLJRC201905)。
文摘An optical fiber dual Fabry-Perot interferometric carbon monoxide gas sensor based on PANI/Co3 O4/GO(PCG)sensing membrane coated on the end face of the optical fiber is proposed and fabricated.One end face of photonic crystal fiber(PCF)without cut-off wavelength is fused with a single-mode fiber(SMF),and the other end face of the PCF is coated with PCG sensing membrane.The collapsed layer formed during the air hole fusion of PCF is used as the first reflector,the interface between PCF and sensing membrane is used as the second reflector,and the interface between the sensing membrane and the air is used as the third reflector,thus the dual Fabry-Pe rot structure sensor is formed.The results show that the sensor has excellent sensitivity and selectivity to carbon monoxide.With the increasing concentration of carbon monoxide gas in the range of 0-60 ppm,the intensity of interference spectrum decreases.The sensitivity of the sensor is 0.3473 dB m/ppm,and its linearity is good.The response time and recovery time are 68 s and 106 s,respectively.The sensor has the advantages of the compact size,low cost,high sensitivity,strong selectivity and simple structure.It is suitable for the sensing detection of low concentration carbon monoxide gas.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61575076 and 61804148)the National Key Research and Development Plan of China(Grant No.2016YFB0402502)
文摘The extinction ratio and insertion loss of spatial light modulator are subject to the material problem, thus limiting its applications. One reflection-type silicon-based spatial light modulator with high reflective materials outside the Fabry-Perot cavity is demonstrated in this paper. The reflectivity values of the outside-cavity materials with different film layer numbers are simulated. The reflectivity values of 6-pair Ta2O5/SiO2 films at 1550 nm are experimentally verified to be as high as 99.9%. The surfaces of 6-pair Ta2O5/SiO2 films are smooth: their root-mean-square roughness values are as small as 0.53 nm. The insertion loss of the device at 1550 nm is only 1.2 dB. The high extinction ratio of the device at 1550 nm and 11 V is achieved to be 29.7 dB. The spatial light modulator has a high extinction ratio and low insertion loss for applications.
基金Supported by the National Natural Science Foundation of Beijing under Grant No 3091002.
文摘The birefringence optical feedback with a folded cavity in HeNe laser is investigated.A theory model based on the equivalent cavity of the Fabry–Perot interferometer is presented.The phase difference between the two intensities in birefringence feedback is twice the retardation of the wave plate.The phase difference is invariable when the length of the feedback cavity changes.With the adoption of a cube corner prism(CCP)to form a folded cavity,the fringe frequency is doubled,and the resolution of the displacement sensor based on birefringence optical feedback with a folded cavity is improved.A resistance chain of 5-fold subdivision and 4-fold logic subdivision is used as further subdivision.The resolution ofλ/80 is obtained eventually;for 632.8 nm HeNe laser it is 7.91 nm.The displacement sensor based on birefringence optical feedback with a folded cavity is simple and of high resolution,large measurement range,low cost,and is of great application potential in industry.
文摘Based on dual-differential comparing principle, an experimental system of optical fiber F-P interferometric micro-displacement measurement is introduced. It is capable of achieving the absolute displacement measurement, and wavelet transforms is adopted as theory fundament to extract the optical F-P interferometric characteristic signal and remove the noise, so its resolution can reach 0. 01 μm in the dynamic range of 0～ 1 mm.
