The strain and temperature sensing performance of fiber-optic Bragg gratings （FBGs） with soft polymeric coating, which can be used to sense internal strain in superconducting coils, are evaluated under variable cryo...The strain and temperature sensing performance of fiber-optic Bragg gratings （FBGs） with soft polymeric coating, which can be used to sense internal strain in superconducting coils, are evaluated under variable cryogenic field and magnetic field. The response to a temperature and strain change of coated-soft polymeric FBGs is tested by comparing with those of coated-metal FBGs. The results indicate that the coated-soft polymeric FBGs can freely detect temperature and thermal strain, their At variable magnetic field, the tested results indicate accuracy and repeatability are also discussed in detail. that the cross-coupling effects of FBGs with different matrixes are not negligible to measure electromagnetic strain during fast excitation. The present results are expected to be able to provide basis measurements on the strain of pulsed superconducting magnet/cable （cable- around-conduit conductors, cable-in-conduit conductors）, independently or utilized together with other strain measurement methods.展开更多
To address the restriction of fiber-optic surface plasmon resonance(SPR) sensors in the field of multi-sample detection, a novel dual-channel fiber-optic SPR sensor based on the cascade of coaxial dual-waveguide D-typ...To address the restriction of fiber-optic surface plasmon resonance(SPR) sensors in the field of multi-sample detection, a novel dual-channel fiber-optic SPR sensor based on the cascade of coaxial dual-waveguide D-type structure and microsphere structure is proposed in this paper. The fiber sidepolishing technique converts the coaxial dual-waveguide fiber into a D-type one, and the evanescent wave in the ring core leaks, generating a D-type sensing region;the fiber optic fused ball push technology converts the coaxial dual waveguides into microspheres, and the stimulated cladding mode evanescent wave leaks, producing the microsphere sensing region. By injecting light into the coaxial dual-waveguide middle core alone, the sensor can realize single-stage sensing in the microsphere sensing area;it can also realize dual-channel sensing in the D-type sensing area and microsphere sensing area by injecting light into the ring core. The refractive index measurement ranges for the two channels are 1.333–1.365 and 1.375–1.405, respectively, with detection sensitivities of 981.56 nm/RIU and 4138 nm/RIU. The sensor combines wavelength division multiplexing and space division multiplexing technologies, presenting a novel research concept for multi-channel fiber SPR sensors.展开更多
Accurate and real-time detection of hydrogen(H_(2))is essential for ensuring energy security.Fiber-optic H_(2) sensors are gaining attention for their integration and remote sensing capabilities.However,they face chal...Accurate and real-time detection of hydrogen(H_(2))is essential for ensuring energy security.Fiber-optic H_(2) sensors are gaining attention for their integration and remote sensing capabilities.However,they face challenges,including complex fabrication processes and limited response times.Here,we propose a fiber-optic H_(2) sensing tip based on Tamm plasmon polariton(TPP)resonance,consisting of a multilayer metal/dielectric Bragg reflector deposited directly on the fiber end facet,simplifying the fabrication process.The fiber-optic TPP(FOTPP)tip exhibits both TPP and multiple Fabry-Perot(FP)resonances simultaneously,with the TPP employed for highly sensitive H_(2) detection.Compared to FP resonance,TPP exhibits more than twice the sensitivity under the same structural dimension without cavity geometry deformation.The excellent performance is attributed to alterations in phase-matching conditions,driven by changes in penetration depth of TPP.Furthermore,the FP mode is utilized to achieve an efficient photothermal effect to catalyze the reaction between H_(2) and the FOTPP structure.Consequently,the response and recovery speeds of the FOTPP tip under resonance-enhanced photothermal assistance are improved by 6.5 and 2.1 times,respectively.Our work offers a novel strategy for developing TPP-integrated fiber-optic tips,refines the theoretical framework of photothermal-assisted detection systems,and provides clear experimental evidence.展开更多
Complex surface shape measurement has been a focus topic in the CAD/CAM field. A popular method for measuring dimensional information is using a 3D coordinate measuring machine (CMM)with a touch trigger probe. The mea...Complex surface shape measurement has been a focus topic in the CAD/CAM field. A popular method for measuring dimensional information is using a 3D coordinate measuring machine (CMM)with a touch trigger probe. The measurement set up with CMM, however, is a time consuming task and the accuracy of the measurement deteriorates as the speed of measurement increase. Non-contact measurement is favored since high speed measurement can be achieved and problems with vibration and friction can be eliminated. Although much research has been conducted in non-contact measurement using image capturing and processing schemes, accuracy is poor and measurement is limited. Some optical technologies developed provide a good accuracy but the dynamic range and versatility is very limited. A novel fiber-optic sensor used for the inspection of complex internal contours is presented in this paper, which is able to measure a surface shape in a non-contact manner with high accuracy and high speed, and is compact and flexible to be incorporated into a CMM. Modulation functions for tilted surface shape measurement, based on the Gaussian distribution of the emitting beam from single-mode fiber (SMF), were derived for specular reflection. The feasibility of the proposed measurement principle was verified by simulations.展开更多
The principle and performance of a fiber-optic Faraday-effect magnetic-field sensor based on an yttrium iron garnet (YIG) and two flux concentrations are described. A single polarization-maintaining optical fiber link...The principle and performance of a fiber-optic Faraday-effect magnetic-field sensor based on an yttrium iron garnet (YIG) and two flux concentrations are described. A single polarization-maintaining optical fiber links the sensor head to the source and detection system, in which the technique of phase shift cancellation is used to cancel the phase shift that accumulatein the optical fiber. Flux concentrators were exploited to enhance the YIG crystal magneto-optic sensitivity .The sensor system exhibited a noise-equivalent field of 8 pT/√Hz and a 3 dB bandwidth of ～10 MHz.展开更多
In this study, we fabricated a sapphire based fiber-optic radiation sensor. To evaluate the fiber- optic radiation sensor, we measured the spectrum and intensity of the luminescence generated from the fiber-optic radi...In this study, we fabricated a sapphire based fiber-optic radiation sensor. To evaluate the fiber- optic radiation sensor, we measured the spectrum and intensity of the luminescence generated from the fiber-optic radiation sensor according to the thickness of the PMMA block by irradiation of gamma rays emitted from a Co-60 source. And the result was compared with the value calculated from the formula of Lambert-Beer.展开更多
A compact and high-resolution fiber-optic refractive index(RI)sensor based on a microwave photonic filter(MPF)is proposed and experimentally validated.The sensing head utilizes a cascaded in-line interferometer fabric...A compact and high-resolution fiber-optic refractive index(RI)sensor based on a microwave photonic filter(MPF)is proposed and experimentally validated.The sensing head utilizes a cascaded in-line interferometer fabricated by an input single-mode fiber(SMF)tapered fusion with no-core fiber-thin-core fiber(TCF)-SMF.The surrounding RI(SRI)can be demodulated by tracing the passband’s central frequency of the MPF,which is constructed by the cascaded in-line interferometer,electro-optic modulator,and a section of dispersion compensation fiber.The sensitivity of the sensor is tailorable through the use of different lengths of TCF.Experimental results reveal that with a 30 mm length of TCF,the sensor achieves a maximum theoretical sensitivity and resolution of-1.403 GHz∕refractive index unit eRIUT and 1.425×10^(-7) RIU,respectively,which is at least 6.3 times higher than what has been reported previously.Furthermore,the sensor exhibits temperature-insensitive characteristics within the range of 25℃-75℃,with a temperatureinduced frequency change of only±1.5 MHz.This value is significantly lower than the frequency change induced by changes in the SRI.The proposed MPF-based cascaded in-line interferometer RI sensor possesses benefits such as easy manufacture,low cost,high resolution,and temperature insensitivity.展开更多
With the rapid development of the Internet of Things(IoT)technology,fiber-optic sensors,as a kind of high-precision and high-sensitivity measurement tool,are increasingly widely used in the field of IoT.This paper out...With the rapid development of the Internet of Things(IoT)technology,fiber-optic sensors,as a kind of high-precision and high-sensitivity measurement tool,are increasingly widely used in the field of IoT.This paper outlines the advantages of fiber-optic sensors over traditional sensors,such as high precision,strong resistance to electromagnetic interference,and long transmission distance.On this basis,the paper discusses the application scenarios of fiber-optic sensors in the Internet of Things,including environmental monitoring,intelligent industry,medical and health care,intelligent transportation,and other fields.It is hoped that this study can provide theoretical support and practical guidance for the further development of fiber-optic sensors in the field of the Internet of Things,as well as promote the innovation and application of IoT.展开更多
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
In this paper, a 10 GHz radio over fiber system is analyzed. The Brillouin fiber-optic ring laser is used in the center station （CS） to suppress the optical carrier for the modulation depth enhancement. Simultaneous...In this paper, a 10 GHz radio over fiber system is analyzed. The Brillouin fiber-optic ring laser is used in the center station （CS） to suppress the optical carrier for the modulation depth enhancement. Simultaneously, the Stockes wave induced by the Brillouin amplification injects and locks the Fabry-Perot （FP） laser to output a signal-mode optical source, which works as the uplink optical carrier.展开更多
A distributed optical-fiber acoustic sensor is an acoustic sensor that uses the optical fiber itself as a photosensitive medium,and is based on Rayleigh backscattering in an optical fiber.The sensor is widely used in ...A distributed optical-fiber acoustic sensor is an acoustic sensor that uses the optical fiber itself as a photosensitive medium,and is based on Rayleigh backscattering in an optical fiber.The sensor is widely used in the safety monitoring of oil and gas pipelines,the classification of weak acoustic signals,defense,seismic prospecting,and other fields.In the field of seismic prospecting,distributed optical-fiber acoustic sensing(DAS)will gradually replace the use of the traditional geophone.The present paper mainly expounds the recent application of DAS,and summarizes recent research achievements of DAS in resource exploration,intrusion monitoring,pattern recognition,and other fields and various DAS system structures.It is found that the high-sensitivity and long-distance sensing capabilities of DAS play a role in the extensive monitoring applications of DAS in engineering.The future application and development of DAS technology are examined,with the hope of promoting the wider application of the DAS technology,which benefits engineering and society.展开更多
Measurements of the thermal deformations of frozen soil samples were performed in the cold laboratory in temperature range from 0°C to-12°C.Fiber Bragg Gratings strain and temperature sensors were used to me...Measurements of the thermal deformations of frozen soil samples were performed in the cold laboratory in temperature range from 0°C to-12°C.Fiber Bragg Gratings strain and temperature sensors were used to measure the deformation and temperature inside the samples.A number of tests with the samples prepared from Kaolin and Cambrian clay saturated with fresh water,and prepared from fine and silt sand saturated with fresh or saline water,are performed.Thermal deformations of the samples are analyzed depending on the cyclic changes of their temperature.展开更多
In order to improve the multiplexing capability of the optical sensors based on the lower interferential optic fiber sensing technology and the white light fiber-optic Mach-Zehnder interferometer,reflective ladder top...In order to improve the multiplexing capability of the optical sensors based on the lower interferential optic fiber sensing technology and the white light fiber-optic Mach-Zehnder interferometer,reflective ladder topology network ( RLT) with tailored formula was proposed. The topology network consists of 6 rungs sensing elements linked by 5 couplers. Two cases with different choices of couplers were contrasted: one is equal coupling ratio,and the other is tailored coupling ratio. Through the simulation of these two cases,the detailed multiplexing capability was analyzed,and accordingly the experiments were also carried out. The simulation results showed that,the tailored formula enhances the multiplexing capability of the structure. In the first case, the maximum number of sensors which can be multiplexed is 8,and in the other case is 12 fiber optic sensors. The experimental results have a good agreement with numerical simulation results. Thus,it is considered expedient to incorporate RLT into large-scale building,grounds,bridges,dams,tunnels,highways and perimeter security.展开更多
This paper presents a method for fabricating a low-cost,highly reproducible miniature optical fiber Fabry-Perot(FP)sensor based on a polydimethylsiloxane(PDMS)end-cap structure.The FP cavity end-cap is formed by the o...This paper presents a method for fabricating a low-cost,highly reproducible miniature optical fiber Fabry-Perot(FP)sensor based on a polydimethylsiloxane(PDMS)end-cap structure.The FP cavity end-cap is formed by the optical fiber end-face and a PDMS droplet deposited onto it.The PDMS deposition is achieved by immersing the fiber end into pre-cured PDMS at a fixed speed,a process requiring careful control of PDMS viscosity and surface tension.By leveraging PDMS’s excellent thermal expansion coefficient,Poisson’s ratio,and other parameters,this method achieves high reproducibility via viscosity-optimized pre-curing,enhanced sensitivity for temperature measurements,and significant cost reduction versus commercial counterparts.Fiber FP sensors are increasingly widely used in biomedical and precision detection fields owing to their significant advantages,including small size,light weight,high sensitivity,and immunity to electromagnetic interference.In the fabrication of fiber FP sensors,using polymer materials is an effective technical approach.These polymers can be applied as coatings on the optical fiber end-face or as interlayer materials embedded between fibers to form the FP cavity structure,which not only significantly improves the overall sensor performance,but also enhances its sensitivity to changes in temperature,pressure,and refractive index.In the final part of this study,we successfully validated the exceptional performance of the PDMS end-cap based fiber FP sensor in detecting different temperatures conditions.Experimental results demonstrate a temperature sensitivity of 0.752 nm/℃for sensors with a 60-μm PDMS end-cap,further confirming the sensor’s reliability and efficiency in practical applications.展开更多
The digital signal-obtaining for gyroscope is given. The single optic-fiber sensor via modulating intensity of light is used as measuring eonlponent . The influence on static transmission properties resulting from the...The digital signal-obtaining for gyroscope is given. The single optic-fiber sensor via modulating intensity of light is used as measuring eonlponent . The influence on static transmission properties resulting from the special working environnlent （e. g. cryogenic and vacuum） ,the measure error because of tile reflector shape of rotor,the abnormity of facula from sensor caused by the existence of engraving error,and tile fixing error of sensor and the error of machine tool＇s initial lignnlent are investigated. The mathematic model in every condition is founded, the simulation and relative experiments ale done and the outeome is analyzed. The mathematic model and method of compensating technology are studied and some relative experiments are made. The result of study is usefid to improvement of the signal-obtaining system.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11302225,11121202 and 11327802the National Key Project of Magneto-Constrained Fusion Energy Development Program under Grant No 2013GB110002the Postdoctoral Science Foundation of China under Grant No 2014M560820
文摘The strain and temperature sensing performance of fiber-optic Bragg gratings （FBGs） with soft polymeric coating, which can be used to sense internal strain in superconducting coils, are evaluated under variable cryogenic field and magnetic field. The response to a temperature and strain change of coated-soft polymeric FBGs is tested by comparing with those of coated-metal FBGs. The results indicate that the coated-soft polymeric FBGs can freely detect temperature and thermal strain, their At variable magnetic field, the tested results indicate accuracy and repeatability are also discussed in detail. that the cross-coupling effects of FBGs with different matrixes are not negligible to measure electromagnetic strain during fast excitation. The present results are expected to be able to provide basis measurements on the strain of pulsed superconducting magnet/cable （cable- around-conduit conductors, cable-in-conduit conductors）, independently or utilized together with other strain measurement methods.
基金supported by the National Natural Science Foundation of China (Grant No. 61705025)the Natural Science Foundation of Chongqing (Grant Nos. cstc2019jcyjmsxm X043 and cstc2018jcyj AX0817)+2 种基金the Fund from the Science and Technology Project Affiliated to the Education Department of Chongqing Municipality (Grant Nos. KJQN201801217, KJQN202001214, KJQN201901226, and KJ1710247)the Fund from Chongqing Key Laboratory of Geological Environment Monitoring and Disaster Early-Warning in Three Gorges Reservoir Area (Grant Nos. ZD2020A0103 and ZD2020A0102)the Fundamental Research Funds for Chongqing Three Gorges University of China (Grant No. 19ZDPY08)。
文摘To address the restriction of fiber-optic surface plasmon resonance(SPR) sensors in the field of multi-sample detection, a novel dual-channel fiber-optic SPR sensor based on the cascade of coaxial dual-waveguide D-type structure and microsphere structure is proposed in this paper. The fiber sidepolishing technique converts the coaxial dual-waveguide fiber into a D-type one, and the evanescent wave in the ring core leaks, generating a D-type sensing region;the fiber optic fused ball push technology converts the coaxial dual waveguides into microspheres, and the stimulated cladding mode evanescent wave leaks, producing the microsphere sensing region. By injecting light into the coaxial dual-waveguide middle core alone, the sensor can realize single-stage sensing in the microsphere sensing area;it can also realize dual-channel sensing in the D-type sensing area and microsphere sensing area by injecting light into the ring core. The refractive index measurement ranges for the two channels are 1.333–1.365 and 1.375–1.405, respectively, with detection sensitivities of 981.56 nm/RIU and 4138 nm/RIU. The sensor combines wavelength division multiplexing and space division multiplexing technologies, presenting a novel research concept for multi-channel fiber SPR sensors.
基金financial supports from National Key Research and Development Program of China(2023YFB3209500)National Natural Science Foundation of China(NSFC)(12274052 and 62171076)+1 种基金Fundamental Research Funds for the Central Universities(DUT24ZD203)Bolian Research Funds of Dalian Maritime University and Fundamental Research Funds for the Central Universities(3132024605).
文摘Accurate and real-time detection of hydrogen(H_(2))is essential for ensuring energy security.Fiber-optic H_(2) sensors are gaining attention for their integration and remote sensing capabilities.However,they face challenges,including complex fabrication processes and limited response times.Here,we propose a fiber-optic H_(2) sensing tip based on Tamm plasmon polariton(TPP)resonance,consisting of a multilayer metal/dielectric Bragg reflector deposited directly on the fiber end facet,simplifying the fabrication process.The fiber-optic TPP(FOTPP)tip exhibits both TPP and multiple Fabry-Perot(FP)resonances simultaneously,with the TPP employed for highly sensitive H_(2) detection.Compared to FP resonance,TPP exhibits more than twice the sensitivity under the same structural dimension without cavity geometry deformation.The excellent performance is attributed to alterations in phase-matching conditions,driven by changes in penetration depth of TPP.Furthermore,the FP mode is utilized to achieve an efficient photothermal effect to catalyze the reaction between H_(2) and the FOTPP structure.Consequently,the response and recovery speeds of the FOTPP tip under resonance-enhanced photothermal assistance are improved by 6.5 and 2.1 times,respectively.Our work offers a novel strategy for developing TPP-integrated fiber-optic tips,refines the theoretical framework of photothermal-assisted detection systems,and provides clear experimental evidence.
文摘Complex surface shape measurement has been a focus topic in the CAD/CAM field. A popular method for measuring dimensional information is using a 3D coordinate measuring machine (CMM)with a touch trigger probe. The measurement set up with CMM, however, is a time consuming task and the accuracy of the measurement deteriorates as the speed of measurement increase. Non-contact measurement is favored since high speed measurement can be achieved and problems with vibration and friction can be eliminated. Although much research has been conducted in non-contact measurement using image capturing and processing schemes, accuracy is poor and measurement is limited. Some optical technologies developed provide a good accuracy but the dynamic range and versatility is very limited. A novel fiber-optic sensor used for the inspection of complex internal contours is presented in this paper, which is able to measure a surface shape in a non-contact manner with high accuracy and high speed, and is compact and flexible to be incorporated into a CMM. Modulation functions for tilted surface shape measurement, based on the Gaussian distribution of the emitting beam from single-mode fiber (SMF), were derived for specular reflection. The feasibility of the proposed measurement principle was verified by simulations.
文摘The principle and performance of a fiber-optic Faraday-effect magnetic-field sensor based on an yttrium iron garnet (YIG) and two flux concentrations are described. A single polarization-maintaining optical fiber links the sensor head to the source and detection system, in which the technique of phase shift cancellation is used to cancel the phase shift that accumulatein the optical fiber. Flux concentrators were exploited to enhance the YIG crystal magneto-optic sensitivity .The sensor system exhibited a noise-equivalent field of 8 pT/√Hz and a 3 dB bandwidth of ～10 MHz.
文摘In this study, we fabricated a sapphire based fiber-optic radiation sensor. To evaluate the fiber- optic radiation sensor, we measured the spectrum and intensity of the luminescence generated from the fiber-optic radiation sensor according to the thickness of the PMMA block by irradiation of gamma rays emitted from a Co-60 source. And the result was compared with the value calculated from the formula of Lambert-Beer.
基金supported by the National Natural Science Foundation of China(Grant No.61975167).
文摘A compact and high-resolution fiber-optic refractive index(RI)sensor based on a microwave photonic filter(MPF)is proposed and experimentally validated.The sensing head utilizes a cascaded in-line interferometer fabricated by an input single-mode fiber(SMF)tapered fusion with no-core fiber-thin-core fiber(TCF)-SMF.The surrounding RI(SRI)can be demodulated by tracing the passband’s central frequency of the MPF,which is constructed by the cascaded in-line interferometer,electro-optic modulator,and a section of dispersion compensation fiber.The sensitivity of the sensor is tailorable through the use of different lengths of TCF.Experimental results reveal that with a 30 mm length of TCF,the sensor achieves a maximum theoretical sensitivity and resolution of-1.403 GHz∕refractive index unit eRIUT and 1.425×10^(-7) RIU,respectively,which is at least 6.3 times higher than what has been reported previously.Furthermore,the sensor exhibits temperature-insensitive characteristics within the range of 25℃-75℃,with a temperatureinduced frequency change of only±1.5 MHz.This value is significantly lower than the frequency change induced by changes in the SRI.The proposed MPF-based cascaded in-line interferometer RI sensor possesses benefits such as easy manufacture,low cost,high resolution,and temperature insensitivity.
文摘With the rapid development of the Internet of Things(IoT)technology,fiber-optic sensors,as a kind of high-precision and high-sensitivity measurement tool,are increasingly widely used in the field of IoT.This paper outlines the advantages of fiber-optic sensors over traditional sensors,such as high precision,strong resistance to electromagnetic interference,and long transmission distance.On this basis,the paper discusses the application scenarios of fiber-optic sensors in the Internet of Things,including environmental monitoring,intelligent industry,medical and health care,intelligent transportation,and other fields.It is hoped that this study can provide theoretical support and practical guidance for the further development of fiber-optic sensors in the field of the Internet of Things,as well as promote the innovation and application of IoT.
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Project supported by the National Natural Science Foundation of China (Grant Nos.60377024, 60877053)the Science Foundation of Science and Technology Commission of Shanghai Municipality (Grant No.08DZ1500115)
文摘In this paper, a 10 GHz radio over fiber system is analyzed. The Brillouin fiber-optic ring laser is used in the center station （CS） to suppress the optical carrier for the modulation depth enhancement. Simultaneously, the Stockes wave induced by the Brillouin amplification injects and locks the Fabry-Perot （FP） laser to output a signal-mode optical source, which works as the uplink optical carrier.
基金supported by the Science and Technology Development Plan of Jilin Province(No.20180201036GX)
文摘A distributed optical-fiber acoustic sensor is an acoustic sensor that uses the optical fiber itself as a photosensitive medium,and is based on Rayleigh backscattering in an optical fiber.The sensor is widely used in the safety monitoring of oil and gas pipelines,the classification of weak acoustic signals,defense,seismic prospecting,and other fields.In the field of seismic prospecting,distributed optical-fiber acoustic sensing(DAS)will gradually replace the use of the traditional geophone.The present paper mainly expounds the recent application of DAS,and summarizes recent research achievements of DAS in resource exploration,intrusion monitoring,pattern recognition,and other fields and various DAS system structures.It is found that the high-sensitivity and long-distance sensing capabilities of DAS play a role in the extensive monitoring applications of DAS in engineering.The future application and development of DAS technology are examined,with the hope of promoting the wider application of the DAS technology,which benefits engineering and society.
基金support of the Innovation Centre SAMCoT (Sustainable Arctic Marine and Coastal Technology), a project of the Norwegian scientific fund
文摘Measurements of the thermal deformations of frozen soil samples were performed in the cold laboratory in temperature range from 0°C to-12°C.Fiber Bragg Gratings strain and temperature sensors were used to measure the deformation and temperature inside the samples.A number of tests with the samples prepared from Kaolin and Cambrian clay saturated with fresh water,and prepared from fine and silt sand saturated with fresh or saline water,are performed.Thermal deformations of the samples are analyzed depending on the cyclic changes of their temperature.
基金Sponsored by the Natural Science Foundation of Heilongjiang Province (Grant No. QC2012C081)the Creative Qualified Scientists and Technicians Foundation of Harbin City (Grant No. RC2012QN001025)the National Natural Science Foundation of China (Grant No. 61107069 and 41174161)
文摘In order to improve the multiplexing capability of the optical sensors based on the lower interferential optic fiber sensing technology and the white light fiber-optic Mach-Zehnder interferometer,reflective ladder topology network ( RLT) with tailored formula was proposed. The topology network consists of 6 rungs sensing elements linked by 5 couplers. Two cases with different choices of couplers were contrasted: one is equal coupling ratio,and the other is tailored coupling ratio. Through the simulation of these two cases,the detailed multiplexing capability was analyzed,and accordingly the experiments were also carried out. The simulation results showed that,the tailored formula enhances the multiplexing capability of the structure. In the first case, the maximum number of sensors which can be multiplexed is 8,and in the other case is 12 fiber optic sensors. The experimental results have a good agreement with numerical simulation results. Thus,it is considered expedient to incorporate RLT into large-scale building,grounds,bridges,dams,tunnels,highways and perimeter security.
文摘This paper presents a method for fabricating a low-cost,highly reproducible miniature optical fiber Fabry-Perot(FP)sensor based on a polydimethylsiloxane(PDMS)end-cap structure.The FP cavity end-cap is formed by the optical fiber end-face and a PDMS droplet deposited onto it.The PDMS deposition is achieved by immersing the fiber end into pre-cured PDMS at a fixed speed,a process requiring careful control of PDMS viscosity and surface tension.By leveraging PDMS’s excellent thermal expansion coefficient,Poisson’s ratio,and other parameters,this method achieves high reproducibility via viscosity-optimized pre-curing,enhanced sensitivity for temperature measurements,and significant cost reduction versus commercial counterparts.Fiber FP sensors are increasingly widely used in biomedical and precision detection fields owing to their significant advantages,including small size,light weight,high sensitivity,and immunity to electromagnetic interference.In the fabrication of fiber FP sensors,using polymer materials is an effective technical approach.These polymers can be applied as coatings on the optical fiber end-face or as interlayer materials embedded between fibers to form the FP cavity structure,which not only significantly improves the overall sensor performance,but also enhances its sensitivity to changes in temperature,pressure,and refractive index.In the final part of this study,we successfully validated the exceptional performance of the PDMS end-cap based fiber FP sensor in detecting different temperatures conditions.Experimental results demonstrate a temperature sensitivity of 0.752 nm/℃for sensors with a 60-μm PDMS end-cap,further confirming the sensor’s reliability and efficiency in practical applications.
文摘The digital signal-obtaining for gyroscope is given. The single optic-fiber sensor via modulating intensity of light is used as measuring eonlponent . The influence on static transmission properties resulting from the special working environnlent （e. g. cryogenic and vacuum） ,the measure error because of tile reflector shape of rotor,the abnormity of facula from sensor caused by the existence of engraving error,and tile fixing error of sensor and the error of machine tool＇s initial lignnlent are investigated. The mathematic model in every condition is founded, the simulation and relative experiments ale done and the outeome is analyzed. The mathematic model and method of compensating technology are studied and some relative experiments are made. The result of study is usefid to improvement of the signal-obtaining system.
