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
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
Fast and stable phase control is essential for many applications in optics. Here, we propose an all-fiber all-optical phase modulation scheme based on a Fabry–Perot interferometer(FPI) and an Er/Yb co-doped fiber(EYD...Fast and stable phase control is essential for many applications in optics. Here, we propose an all-fiber all-optical phase modulation scheme based on a Fabry–Perot interferometer(FPI) and an Er/Yb co-doped fiber(EYDF). By using the EYDF as an F-P cavity via rational design, a phase shift with a modulation sensitivity of 0.0312π/mW is introduced to the modulator.The phase shifts in the EYDF consist of a thermal phase shift and a nonlinear phase shift with a ratio of 19:1, and the corresponding temporal responses of the modulation are 204 ms and 2.5 ms, respectively. In addition, the compact FPI is encapsulated to provide excellent stability for the modulator.展开更多
In this study,we present a dual-Fizeau-interferometer-based high-speed and wide-range fiber-optic Fabry-Perot(F-P)demodulation system.We employ two Fizeau interferometers with air cavity thickness satisfying the quadr...In this study,we present a dual-Fizeau-interferometer-based high-speed and wide-range fiber-optic Fabry-Perot(F-P)demodulation system.We employ two Fizeau interferometers with air cavity thickness satisfying the quadrature requirement to increase the demodulation speed and broaden the demodulation range in order to address the issues of the existing fiber F-P demodulation system's sluggish demodulation rate and limited range.In order to investigate the demodulation properties of the dual-Fizeau-interferometer-based demodulation system,we derive and create a theoretical model of the system.The theoretical model,which primarily consists of the structural design of the interferometer and the study of the center wavelength of the light sources and their bandwidth selection,is used to construct the optical structure of the demodulation system.According to the calculation results,the demodulated signal exhibits the best contrast ratio when the two light sources'respective center wavelengths are 780nm and 850nm,and their bandwidths are 28nm and 30 nm.Finally,we finish evaluating the demodulation system's demodulation performance,parameter calibration,and assembly debugging.The test results demonstrate the constant operation of the demodulation system,an update rate of 100kHz,a demodulation range of 4.74μm,and a cavity length resolution of approximately 5 nm.Additionally,the system can perform high speed demodulation thanks to the light emitting diode's(LED's)nanosecond level switching speed and the usage of a single point detector.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
Pressure sensors based on fiber-optic extrinsic Fabry-Perot interferometer(EFPI)have been extensively applied in various industrial and biomedical fields.In this paper,some key improvements of EFPI-based pressure sens...Pressure sensors based on fiber-optic extrinsic Fabry-Perot interferometer(EFPI)have been extensively applied in various industrial and biomedical fields.In this paper,some key improvements of EFPI-based pressure sensors such as the controlled thermal bonding technique,diaphragm-based EFPI sensors,and white light interference technology have been reviewed.Recent progress on signal demodulation method and applications of EFPI-based pressure sensors has been introduced.Signal demodulation algorithms based on the cross correlation and mean square error(MSE)estimation have been proposed for retrieving the cavity length of EFPI.Absolute measurement with a resolution of 0.08 nm over large dynamic range has been carried out.For downhole monitoring,an EFPI and a fiber Bragg grating(FBG)cascade multiplexing fiber-optic sensor system has been developed,which can operate in temperature 300℃with a good long-term stability and extremely low temperature cross-sensitivity.Diaphragm-based EFPI pressure sensors have been successfully used for low pressure and acoustic wave detection.Experimental results show that a sensitivity of 31 mV/Pa in the frequency range of 100 Hz to 12.7 kHz for aeroacoustic wave detection has been obtained.展开更多
A novel scheme is proposed to transform a Gaussian optical pulse to a millimeter-wave （mm-wave） frequency modulation pulse by using a Fabry-Perot interferometer （FPI） for radio-over-fiber （ROF） system. It is sho...A novel scheme is proposed to transform a Gaussian optical pulse to a millimeter-wave （mm-wave） frequency modulation pulse by using a Fabry-Perot interferometer （FPI） for radio-over-fiber （ROF） system. It is shown that modulation frequency of mm-wave is determined by the optical path of the Fabry-Perot （F-P） cavity, and amplitude decay time and energy transfer efficiency axe related to the reflectivity of the F-P cavity mirror. The effect of pulse train extension on inter-symbol interference is also discussed.展开更多
A versatile fiber interferometer was proposed for high precision measurement. The sensor exploited a double-cavity within the unique sensing arm of an extrinsic-type fiber Fabry-Perot interferometer to produce the qua...A versatile fiber interferometer was proposed for high precision measurement. The sensor exploited a double-cavity within the unique sensing arm of an extrinsic-type fiber Fabry-Perot interferometer to produce the quadrature phase-shifted interference fringes. Interference signal processing was carried out using a modified zero-crossing （fringe） counting technique to demodulate two sets of fringes. The fiber interferometer has been successfully employed for dynamic displacement measurement under different displacement profiles over a range of 0.7 p.m to 140 p.m. A dedicated computer incorporating the demodulation algorithm was next used to interpret these detected data as well as plot the displacement information with a resolution of 2/64. A commercial displacement sensor was employed for comparison purposes with the experimental data obtained from the fiber interferometer as well as to gauge its performance, resulting in the maximum error of 2.8% over the entire displacement range studied.展开更多
A novel zeolite-coated fiber sensors for detection of volatile organic compounds （VOCs） based on the Fabry-Perot interferometer was proposed and demonstrated. The sensor comprised a polycrystalline silicalite thin f...A novel zeolite-coated fiber sensors for detection of volatile organic compounds （VOCs） based on the Fabry-Perot interferometer was proposed and demonstrated. The sensor comprised a polycrystalline silicalite thin film grown up on the cleaved end face of a standard single-mode fiber. The inline Fabry-Perot cavity was composed by the end face of the single-mode fiber and the thin film. The sensor device operated by measuring the interference signal, which was a function of the amount of chemical vapor adsorption in its crystalline micro porous structure. Experimental results showed that the proposed VOC sensor worked well and the sensitivities were 2.78×10^-3dB/ppm when the concentration ranged from 350ppm to 2100ppm and 1.23×10^-3 dB/ppm when the concentration ranged from 2100ppm to 5250 ppm.展开更多
A curvature sensor based on an Fabry-Perot （FP） interferometer was proposed. A capillary silica tube was fusion spliced between two single mode fibers, producing an FP cavity. Two FP sensors with different cavity le...A curvature sensor based on an Fabry-Perot （FP） interferometer was proposed. A capillary silica tube was fusion spliced between two single mode fibers, producing an FP cavity. Two FP sensors with different cavity lengths were developed and subjected to curvature and temperature. The FP sensor with longer cavity showed three distinct operating regions for the curvature measurement. Namely, a linear response was shown for an intermediate curvature radius range, presenting a maximum sensitivity of 68.52 pm/m-1. When subjected to temperature, the sensing head produced a similar response for different curvature radii, with a sensitivity varying from 0.84 pm/℃ to 0.89 pm/℃, which resulted in a small cross-sensitivity to temperature when the FP sensor was subjected to curvature. The FP cavity with shorter length presented low sensitivity to curvature.展开更多
In this paper, a sinusoidal phase-modulating Fabry-Perot interferometer is proposed to measure angular displacement. The usefulness of the interferometer is demonstrated by simulations and experiments.
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.
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 Key Research and Development Program of China (No. 2018YFC1503703)the Shanghai Academy of Spaceflight Technology(No. SAST2019-127)。
文摘Fast and stable phase control is essential for many applications in optics. Here, we propose an all-fiber all-optical phase modulation scheme based on a Fabry–Perot interferometer(FPI) and an Er/Yb co-doped fiber(EYDF). By using the EYDF as an F-P cavity via rational design, a phase shift with a modulation sensitivity of 0.0312π/mW is introduced to the modulator.The phase shifts in the EYDF consist of a thermal phase shift and a nonlinear phase shift with a ratio of 19:1, and the corresponding temporal responses of the modulation are 204 ms and 2.5 ms, respectively. In addition, the compact FPI is encapsulated to provide excellent stability for the modulator.
文摘In this study,we present a dual-Fizeau-interferometer-based high-speed and wide-range fiber-optic Fabry-Perot(F-P)demodulation system.We employ two Fizeau interferometers with air cavity thickness satisfying the quadrature requirement to increase the demodulation speed and broaden the demodulation range in order to address the issues of the existing fiber F-P demodulation system's sluggish demodulation rate and limited range.In order to investigate the demodulation properties of the dual-Fizeau-interferometer-based demodulation system,we derive and create a theoretical model of the system.The theoretical model,which primarily consists of the structural design of the interferometer and the study of the center wavelength of the light sources and their bandwidth selection,is used to construct the optical structure of the demodulation system.According to the calculation results,the demodulated signal exhibits the best contrast ratio when the two light sources'respective center wavelengths are 780nm and 850nm,and their bandwidths are 28nm and 30 nm.Finally,we finish evaluating the demodulation system's demodulation performance,parameter calibration,and assembly debugging.The test results demonstrate the constant operation of the demodulation system,an update rate of 100kHz,a demodulation range of 4.74μm,and a cavity length resolution of approximately 5 nm.Additionally,the system can perform high speed demodulation thanks to the light emitting diode's(LED's)nanosecond level switching speed and the usage of a single point detector.
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.
文摘Pressure sensors based on fiber-optic extrinsic Fabry-Perot interferometer(EFPI)have been extensively applied in various industrial and biomedical fields.In this paper,some key improvements of EFPI-based pressure sensors such as the controlled thermal bonding technique,diaphragm-based EFPI sensors,and white light interference technology have been reviewed.Recent progress on signal demodulation method and applications of EFPI-based pressure sensors has been introduced.Signal demodulation algorithms based on the cross correlation and mean square error(MSE)estimation have been proposed for retrieving the cavity length of EFPI.Absolute measurement with a resolution of 0.08 nm over large dynamic range has been carried out.For downhole monitoring,an EFPI and a fiber Bragg grating(FBG)cascade multiplexing fiber-optic sensor system has been developed,which can operate in temperature 300℃with a good long-term stability and extremely low temperature cross-sensitivity.Diaphragm-based EFPI pressure sensors have been successfully used for low pressure and acoustic wave detection.Experimental results show that a sensitivity of 31 mV/Pa in the frequency range of 100 Hz to 12.7 kHz for aeroacoustic wave detection has been obtained.
文摘A novel scheme is proposed to transform a Gaussian optical pulse to a millimeter-wave （mm-wave） frequency modulation pulse by using a Fabry-Perot interferometer （FPI） for radio-over-fiber （ROF） system. It is shown that modulation frequency of mm-wave is determined by the optical path of the Fabry-Perot （F-P） cavity, and amplitude decay time and energy transfer efficiency axe related to the reflectivity of the F-P cavity mirror. The effect of pulse train extension on inter-symbol interference is also discussed.
文摘A versatile fiber interferometer was proposed for high precision measurement. The sensor exploited a double-cavity within the unique sensing arm of an extrinsic-type fiber Fabry-Perot interferometer to produce the quadrature phase-shifted interference fringes. Interference signal processing was carried out using a modified zero-crossing （fringe） counting technique to demodulate two sets of fringes. The fiber interferometer has been successfully employed for dynamic displacement measurement under different displacement profiles over a range of 0.7 p.m to 140 p.m. A dedicated computer incorporating the demodulation algorithm was next used to interpret these detected data as well as plot the displacement information with a resolution of 2/64. A commercial displacement sensor was employed for comparison purposes with the experimental data obtained from the fiber interferometer as well as to gauge its performance, resulting in the maximum error of 2.8% over the entire displacement range studied.
文摘A novel zeolite-coated fiber sensors for detection of volatile organic compounds （VOCs） based on the Fabry-Perot interferometer was proposed and demonstrated. The sensor comprised a polycrystalline silicalite thin film grown up on the cleaved end face of a standard single-mode fiber. The inline Fabry-Perot cavity was composed by the end face of the single-mode fiber and the thin film. The sensor device operated by measuring the interference signal, which was a function of the amount of chemical vapor adsorption in its crystalline micro porous structure. Experimental results showed that the proposed VOC sensor worked well and the sensitivities were 2.78×10^-3dB/ppm when the concentration ranged from 350ppm to 2100ppm and 1.23×10^-3 dB/ppm when the concentration ranged from 2100ppm to 5250 ppm.
文摘A curvature sensor based on an Fabry-Perot （FP） interferometer was proposed. A capillary silica tube was fusion spliced between two single mode fibers, producing an FP cavity. Two FP sensors with different cavity lengths were developed and subjected to curvature and temperature. The FP sensor with longer cavity showed three distinct operating regions for the curvature measurement. Namely, a linear response was shown for an intermediate curvature radius range, presenting a maximum sensitivity of 68.52 pm/m-1. When subjected to temperature, the sensing head produced a similar response for different curvature radii, with a sensitivity varying from 0.84 pm/℃ to 0.89 pm/℃, which resulted in a small cross-sensitivity to temperature when the FP sensor was subjected to curvature. The FP cavity with shorter length presented low sensitivity to curvature.
文摘In this paper, a sinusoidal phase-modulating Fabry-Perot interferometer is proposed to measure angular displacement. The usefulness of the interferometer is demonstrated by simulations and experiments.
