Pipelines are one of the most important modern energy transportation methods,used especially for the transportation of certain dangerous energy media materials such as crude oil,natural gas,and chemical raw materials....Pipelines are one of the most important modern energy transportation methods,used especially for the transportation of certain dangerous energy media materials such as crude oil,natural gas,and chemical raw materials.New requirements have been put forward for the health monitoring and early security warning of pipelines because of the large-scale and complicated development trend of the pipe network system.To achieve an accurate assessment of the health conditions of pipeline infrastructure,obtaining as many precise operating parameters as possible,particularly at some critical parts of the pipeline,is necessary.Therefore,a novel type of fiber grating strain sensor array is proposed herein to monitor the pipeline hoop strain.The sensor utilizes fiber grating characteristics such as light weight,corrosion resistance,remote transmission,and strong environmental adaptability.The fiber containing the grating measurement points is implanted into the composite material to complete the sensitization encapsulation and protection of the bare fiber grating.The design of the sensor array fulfills the requirements for monitoring pipeline mass data,making it easy to form a pipeline health monitoring sensor network.The sensor sensitivity is researched by using a combination of theoretical and experimental analysis.A sensitivity test,as well as linearity and stability tests,are performed on the sensor.The experimental results show that the average sensitivity of the sensor is 14.86 pm/με,and the error from the theoretical calculation analysis value is 8.75%.Due to its high reliability,good linear response and long-term stability,and the ability to reflect the exact strain change of the outer wall of the pipeline,the designed sensor can support longterm online pipeline monitoring.The fiber grating sensor array network has successfully realized the monitoring of the pipeline’s internal operation by using external strain changes.In addition to the performance benefits,there are other merits associated with the applicability of the sensor namely simple structure,compact size,manufacturing ease,and exterior installation ease.展开更多
The measuring method of structure damage during vibrating has been developed by applying simple supported beam as object of study, fiber Bragg grating strain sensing array as the measuring method, and wavelet package ...The measuring method of structure damage during vibrating has been developed by applying simple supported beam as object of study, fiber Bragg grating strain sensing array as the measuring method, and wavelet package analysis as signal extracting tools. The damage data of simple supported beam at vibrating state has been collected. The damage characteristic indexes have been extracted based on analyzing and handling the damage data with wavelet analysis. The experiment shows that fiber Bragg grating strain sensing array can sensitively measure the experimental data of simple supported beam at vibrating state. The fiber Bragg grating strain sensing array measuring is a new method in dynamic measurement.展开更多
The multi-crack damages modal of simple supported beam has been build, at the vibrating status, the multi-damage detecting method of simple supported beam measured by fiber Bragg grating strain sensing array has been ...The multi-crack damages modal of simple supported beam has been build, at the vibrating status, the multi-damage detecting method of simple supported beam measured by fiber Bragg grating strain sensing array has been studied. From 0 hz to 200 hz, using exciter vibrating simple supported beam, with different damages, resonant frequency of simple supported beam has changed. So, when the damage appears in simple supported beam, the local rigidity will decrease, the resonant frequency of simple supported beam will be affected, the damage status of simple supported beam have been determined by this. The experimental result indicates that the resonant frequency of simple supported beam has changed when there is no damage, one damage, two damages, three damages on simple supported beam. According to this, the fiber Bragg grating strain sensing array can detect multi-crack damage of simple supported beam under vibrating status.展开更多
Miniaturized fiber-Bragg-grating(FBG)interrogators are of interest for applications in the areas where weight and size controlling is important,e.g.,airplanes and aerospace or in-situ monitoring.An ultra-compact high-...Miniaturized fiber-Bragg-grating(FBG)interrogators are of interest for applications in the areas where weight and size controlling is important,e.g.,airplanes and aerospace or in-situ monitoring.An ultra-compact high-precision on-chip interrogator is proposed based on a tailored arrayed waveguide grating(AWG)on a silicon-on-insulator(SOI)platform.The on-chip interrogator enables continuous wavelength interrogation from 1544 nm to 1568 nm with the wavelength accuracy of less than 1 pm[the root-mean-square error(RMSE)is 0.73 pm]over the whole wavelength range.The chip loss is less than 5 dB.The 1×16 AWG is optimized to achieve a large bandwidth and a low noise level at each channel,and the FBG reflection peaks can be detected by multiple output channels of the AWG.The fabricated AWG is utilized to interrogate FBG sensors through the center of gravity(CoG)algorithm.The validation of an on-chip FBG interrogator that works with sub-picometer wavelength accuracy in a broad wavelength range shows large potential for applications in miniaturized fiber optic sensing systems.展开更多
A pressure tactile sensor based on the fiber Bragg grating (FBG) array is introduced in this paper, and the numerical simulation of its elastic body was implemented by finite element software (ANSYS). On the basis...A pressure tactile sensor based on the fiber Bragg grating (FBG) array is introduced in this paper, and the numerical simulation of its elastic body was implemented by finite element software (ANSYS). On the basis of simulation, fiber Bragg grating strings were implanted in flexible silicone to realize the sensor fabrication process, and a testing system was built. A series of calibration tests were done via the high precision universal press machine. The tactile sensor array perceived external pressure, which is demodulated by the fiber grating demodulation instrument, and three-dimension pictures were programmed to display visually the position and size. At the same time, a dynamic contact experiment of the sensor was conducted for simulating robot encountering other objects in the unknown environment. The experimental results show that the sensor has good linearity, repeatability, and has the good effect of dynamic response, and its pressure sensitivity was 0.03 nm/N In addition, the sensor also has advantages of anti-electromagnetic interference, good flexibility, simple structure, low cost and so on, which is expected to be used in the wearable artificial skin in the future.展开更多
A novel time/wavelength-multiplexed fiber Bragg grating sensor array is presented. This type of sensor array has the advantages of more points for multi-point measurement, simple structure and low cost.
A two-dimensional(2D) optical true-time delay(TTD) beam-forming system using a compact fiber grating prism(FGP) for a planar phased array antenna(PAA) is proposed. The optical beam-forming system mainly consists of a ...A two-dimensional(2D) optical true-time delay(TTD) beam-forming system using a compact fiber grating prism(FGP) for a planar phased array antenna(PAA) is proposed. The optical beam-forming system mainly consists of a TTD unit based on the same compact FGP, one tunable laser for elevation beam steering, and a controlled wavelength converter for azimuth beam steering. A planar PAA using such 2D optical TTD unit has advantages such as compactness, low bandwidth requirement for tunable laser sources, and potential for large-scale system implementations. The proof-of-concept experiment results demonstrate the feasibility of the proposed scheme.展开更多
Two array waveguide grating (AWGs) based fiber ring lasers are experimentally demonstrated. Either of them achieves wavelength discrete tuning of 32 nm, or yields simultaneously lasing up to four channels with -7 dBm ...Two array waveguide grating (AWGs) based fiber ring lasers are experimentally demonstrated. Either of them achieves wavelength discrete tuning of 32 nm, or yields simultaneously lasing up to four channels with -7 dBm output power for each channel.展开更多
A full-open-cavity wavelength-tunable random fiber laser(WT-RFL) with compact structure and hundreds of picometers tuning range is proposed and demonstrated. A π fiber Bragg grating(FBG) is used in the WT-RFL as a fi...A full-open-cavity wavelength-tunable random fiber laser(WT-RFL) with compact structure and hundreds of picometers tuning range is proposed and demonstrated. A π fiber Bragg grating(FBG) is used in the WT-RFL as a filter to select lasing wavelengths. The two random Bragg grating arrays(RBGAs) and a section of high gain erbium-doped fiber result in a low lasing threshold and high stability. A numerical model to analyze the tunable characteristics is developed. The results show that the laser threshold is 22 m W, and the maximum peak-power fluctuation is 0.55 d B. To the best of our knowledge, it is the first time that a compact and full-open-cavity WT-RFL with two RBGAs and a π-FBG is proposed.展开更多
The space sheet for a solar array structure is large in dimension, and flexible to induce complex distortion. It is difficult to measure the distortion. A large-scale flexible test prototype system is built for sheet ...The space sheet for a solar array structure is large in dimension, and flexible to induce complex distortion. It is difficult to measure the distortion. A large-scale flexible test prototype system is built for sheet structure vibration monitoring based on the vibration information of the solar array in space. The system provides an intelligent test method for flexible space structure with embedded sensors and non-visualization reinstruction. Multiple fiber Bragg grating (FBG) sensors are packaged and embedded into the structure with spatial division multiplexing (SDM) and wavelength division multiplexing (WDM). The sensor interrogator distinguishes wavelength shifts that can be turned into curvature of the curve. The structure shape is reconstructed based on the curvature information and the arc-length, and then displayed. The experiment shows that the system has a high FBG sensitivity. The reconstruction algorithm is fast with high precision. The system has great potential for use in health monitoring of the space sheet structure.展开更多
Sampled fiber grating is a special superstructure fiber Bragg grating with a wide range of applications in many fields.In this work,based on drawing tower in-line fabrication system,a new preparation method of the sam...Sampled fiber grating is a special superstructure fiber Bragg grating with a wide range of applications in many fields.In this work,based on drawing tower in-line fabrication system,a new preparation method of the sampled fiber grating is proposed and experimentally demonstrated.Experimental result shows that the obtained sampled fiber gratings possess dense reflection spectra,with a minimum reflection peak interval of only 0.09 nm.This method exhibits promising application prospect in the fabrication of the high-quality sampled fiber grating.On the other hand,the spectral characteristics of the sampled fiber grating are analyzed when the sub-grating is affected by the external physical quantities such as,in this paper,strain.Wavelength shift and intensity change in the reflection peak of the spectra indicate that the grating is affected differently by micro strains,due to the different spatial positions along the axis of the sampled fiber grating.This work is aimed at exploring the potential applications of the sampled fiber grating in quasi-distributed micro-area sensing with the millimeter level.展开更多
In this paper, an optical beam-former in receiving mode has been proposed and experimentally demonstrated. The requirement in system's hardware has been dramatically reduced using a hybrid approach between dispers...In this paper, an optical beam-former in receiving mode has been proposed and experimentally demonstrated. The requirement in system's hardware has been dramatically reduced using a hybrid approach between dispersive and non-dispersive delay. The proposed system is capable of supporting RF signals from L-band to X-band, with large coverage and strong robustness against the grating's group delay ripples.展开更多
This article presents a high-speed distributed vibration sensing based on Mach-Zehnder-OTDR (optical time-domain reflectometry). Ultra-weak fiber Bragg gratings (UWFBG), whose backward light intensity is 2-4 order...This article presents a high-speed distributed vibration sensing based on Mach-Zehnder-OTDR (optical time-domain reflectometry). Ultra-weak fiber Bragg gratings (UWFBG), whose backward light intensity is 2-4 orders of magnitude higher than that of Rayleigh scattering, are used as the reflection markers. A medium-coherence laser can substitute conventional narrow bandwidth source to achieve an excellent performance of distributed vibration sensing since our unbalanced interferometer matches the interval of UWFBGs. The 3 m of spatial resolution of coherent detection and multiple simultaneous vibration sources locating can be realized based on OTDR. The enhanced signal to noise ratio (SNR) enables fast detection of distributed vibration without averaging. The fastest vibration of 25 kHz and the slowest vibration of 10Hz can be detected with our system successfully, and the linearity is 0.9896 with a maximum deviation of 3.46nε.展开更多
基金supported by the National Key R&D Program of China(Grants 2018YFF0214700)Hubei Province Science and Technology Special Major Project(2016AAA008)New Research and Development Agency Project of Zhongshan Science and Technology Bureau(2017F2FC003)in China.
文摘Pipelines are one of the most important modern energy transportation methods,used especially for the transportation of certain dangerous energy media materials such as crude oil,natural gas,and chemical raw materials.New requirements have been put forward for the health monitoring and early security warning of pipelines because of the large-scale and complicated development trend of the pipe network system.To achieve an accurate assessment of the health conditions of pipeline infrastructure,obtaining as many precise operating parameters as possible,particularly at some critical parts of the pipeline,is necessary.Therefore,a novel type of fiber grating strain sensor array is proposed herein to monitor the pipeline hoop strain.The sensor utilizes fiber grating characteristics such as light weight,corrosion resistance,remote transmission,and strong environmental adaptability.The fiber containing the grating measurement points is implanted into the composite material to complete the sensitization encapsulation and protection of the bare fiber grating.The design of the sensor array fulfills the requirements for monitoring pipeline mass data,making it easy to form a pipeline health monitoring sensor network.The sensor sensitivity is researched by using a combination of theoretical and experimental analysis.A sensitivity test,as well as linearity and stability tests,are performed on the sensor.The experimental results show that the average sensitivity of the sensor is 14.86 pm/με,and the error from the theoretical calculation analysis value is 8.75%.Due to its high reliability,good linear response and long-term stability,and the ability to reflect the exact strain change of the outer wall of the pipeline,the designed sensor can support longterm online pipeline monitoring.The fiber grating sensor array network has successfully realized the monitoring of the pipeline’s internal operation by using external strain changes.In addition to the performance benefits,there are other merits associated with the applicability of the sensor namely simple structure,compact size,manufacturing ease,and exterior installation ease.
文摘The measuring method of structure damage during vibrating has been developed by applying simple supported beam as object of study, fiber Bragg grating strain sensing array as the measuring method, and wavelet package analysis as signal extracting tools. The damage data of simple supported beam at vibrating state has been collected. The damage characteristic indexes have been extracted based on analyzing and handling the damage data with wavelet analysis. The experiment shows that fiber Bragg grating strain sensing array can sensitively measure the experimental data of simple supported beam at vibrating state. The fiber Bragg grating strain sensing array measuring is a new method in dynamic measurement.
文摘The multi-crack damages modal of simple supported beam has been build, at the vibrating status, the multi-damage detecting method of simple supported beam measured by fiber Bragg grating strain sensing array has been studied. From 0 hz to 200 hz, using exciter vibrating simple supported beam, with different damages, resonant frequency of simple supported beam has changed. So, when the damage appears in simple supported beam, the local rigidity will decrease, the resonant frequency of simple supported beam will be affected, the damage status of simple supported beam have been determined by this. The experimental result indicates that the resonant frequency of simple supported beam has changed when there is no damage, one damage, two damages, three damages on simple supported beam. According to this, the fiber Bragg grating strain sensing array can detect multi-crack damage of simple supported beam under vibrating status.
基金This work wasssupported by the National Natural Science Foundation of China(Grant Nos.62020106002 and 61735017)Innovation Project of Zhejiang Laboratory(Grant No.2021MG0AL01)+2 种基金the Youth Foundation of Zhejiang Laboratory(Grant No.2020MC0AA08)Major Scientific Research Project of Zhejiang Laboratory(Grant No.2019MC0AD02)National Key Basic Research Program of China(Grant No.2021YFC2401403).
文摘Miniaturized fiber-Bragg-grating(FBG)interrogators are of interest for applications in the areas where weight and size controlling is important,e.g.,airplanes and aerospace or in-situ monitoring.An ultra-compact high-precision on-chip interrogator is proposed based on a tailored arrayed waveguide grating(AWG)on a silicon-on-insulator(SOI)platform.The on-chip interrogator enables continuous wavelength interrogation from 1544 nm to 1568 nm with the wavelength accuracy of less than 1 pm[the root-mean-square error(RMSE)is 0.73 pm]over the whole wavelength range.The chip loss is less than 5 dB.The 1×16 AWG is optimized to achieve a large bandwidth and a low noise level at each channel,and the FBG reflection peaks can be detected by multiple output channels of the AWG.The fabricated AWG is utilized to interrogate FBG sensors through the center of gravity(CoG)algorithm.The validation of an on-chip FBG interrogator that works with sub-picometer wavelength accuracy in a broad wavelength range shows large potential for applications in miniaturized fiber optic sensing systems.
文摘A pressure tactile sensor based on the fiber Bragg grating (FBG) array is introduced in this paper, and the numerical simulation of its elastic body was implemented by finite element software (ANSYS). On the basis of simulation, fiber Bragg grating strings were implanted in flexible silicone to realize the sensor fabrication process, and a testing system was built. A series of calibration tests were done via the high precision universal press machine. The tactile sensor array perceived external pressure, which is demodulated by the fiber grating demodulation instrument, and three-dimension pictures were programmed to display visually the position and size. At the same time, a dynamic contact experiment of the sensor was conducted for simulating robot encountering other objects in the unknown environment. The experimental results show that the sensor has good linearity, repeatability, and has the good effect of dynamic response, and its pressure sensitivity was 0.03 nm/N In addition, the sensor also has advantages of anti-electromagnetic interference, good flexibility, simple structure, low cost and so on, which is expected to be used in the wearable artificial skin in the future.
基金Supported by Beijing Education Administration Foundation (00KG040)
文摘A novel time/wavelength-multiplexed fiber Bragg grating sensor array is presented. This type of sensor array has the advantages of more points for multi-point measurement, simple structure and low cost.
基金supported by the National "973" Project of China(Nos.2010CB328202,2010CB328204,and 2012CB315604)the National Natural Science Foundation of China(Nos.61271191 and 61001124)+3 种基金the National "863" Project of China(No.2012AA011302)the Program for New Century Excellent Talents in University(No.NCET-12-0793)the Beijing Nova Program(No.2011065)the Fundamental Research Funds for the Central Universities
文摘A two-dimensional(2D) optical true-time delay(TTD) beam-forming system using a compact fiber grating prism(FGP) for a planar phased array antenna(PAA) is proposed. The optical beam-forming system mainly consists of a TTD unit based on the same compact FGP, one tunable laser for elevation beam steering, and a controlled wavelength converter for azimuth beam steering. A planar PAA using such 2D optical TTD unit has advantages such as compactness, low bandwidth requirement for tunable laser sources, and potential for large-scale system implementations. The proof-of-concept experiment results demonstrate the feasibility of the proposed scheme.
文摘Two array waveguide grating (AWGs) based fiber ring lasers are experimentally demonstrated. Either of them achieves wavelength discrete tuning of 32 nm, or yields simultaneously lasing up to four channels with -7 dBm output power for each channel.
基金supported by the National Natural Science Foundation of China (NSFC) (Nos. 61875185 and U1939207)the Scientific Instrument Developing Project of the Chinese Academy of Sciences+1 种基金the Strategic Priority Research Program A of the CAS (No. XDA22010201)the Shenzhen Science and Technology Research Funding (No. JCYJ20190814110601663)
文摘A full-open-cavity wavelength-tunable random fiber laser(WT-RFL) with compact structure and hundreds of picometers tuning range is proposed and demonstrated. A π fiber Bragg grating(FBG) is used in the WT-RFL as a filter to select lasing wavelengths. The two random Bragg grating arrays(RBGAs) and a section of high gain erbium-doped fiber result in a low lasing threshold and high stability. A numerical model to analyze the tunable characteristics is developed. The results show that the laser threshold is 22 m W, and the maximum peak-power fluctuation is 0.55 d B. To the best of our knowledge, it is the first time that a compact and full-open-cavity WT-RFL with two RBGAs and a π-FBG is proposed.
基金Project supported by the National Natural Science Foundation China (Grant No.90405013)
文摘The space sheet for a solar array structure is large in dimension, and flexible to induce complex distortion. It is difficult to measure the distortion. A large-scale flexible test prototype system is built for sheet structure vibration monitoring based on the vibration information of the solar array in space. The system provides an intelligent test method for flexible space structure with embedded sensors and non-visualization reinstruction. Multiple fiber Bragg grating (FBG) sensors are packaged and embedded into the structure with spatial division multiplexing (SDM) and wavelength division multiplexing (WDM). The sensor interrogator distinguishes wavelength shifts that can be turned into curvature of the curve. The structure shape is reconstructed based on the curvature information and the arc-length, and then displayed. The experiment shows that the system has a high FBG sensitivity. The reconstruction algorithm is fast with high precision. The system has great potential for use in health monitoring of the space sheet structure.
基金This work was supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.61290311 and 61735013)the Major Scientific and Technological Innovation Project in Hubei Province(Grant No.2015AAA001).
文摘Sampled fiber grating is a special superstructure fiber Bragg grating with a wide range of applications in many fields.In this work,based on drawing tower in-line fabrication system,a new preparation method of the sampled fiber grating is proposed and experimentally demonstrated.Experimental result shows that the obtained sampled fiber gratings possess dense reflection spectra,with a minimum reflection peak interval of only 0.09 nm.This method exhibits promising application prospect in the fabrication of the high-quality sampled fiber grating.On the other hand,the spectral characteristics of the sampled fiber grating are analyzed when the sub-grating is affected by the external physical quantities such as,in this paper,strain.Wavelength shift and intensity change in the reflection peak of the spectra indicate that the grating is affected differently by micro strains,due to the different spatial positions along the axis of the sampled fiber grating.This work is aimed at exploring the potential applications of the sampled fiber grating in quasi-distributed micro-area sensing with the millimeter level.
文摘In this paper, an optical beam-former in receiving mode has been proposed and experimentally demonstrated. The requirement in system's hardware has been dramatically reduced using a hybrid approach between dispersive and non-dispersive delay. The proposed system is capable of supporting RF signals from L-band to X-band, with large coverage and strong robustness against the grating's group delay ripples.
基金This work was supported in part by the National Natural Science Foundation of China (Gram No. 61735031), Natural Science Foundation of Hubei Province of China (Grant No. 2018CFA056), and the Excellent Dissertation Cultivation Funds of Wuhan University of Technology (Grant No. 2017-YS-057).
文摘This article presents a high-speed distributed vibration sensing based on Mach-Zehnder-OTDR (optical time-domain reflectometry). Ultra-weak fiber Bragg gratings (UWFBG), whose backward light intensity is 2-4 orders of magnitude higher than that of Rayleigh scattering, are used as the reflection markers. A medium-coherence laser can substitute conventional narrow bandwidth source to achieve an excellent performance of distributed vibration sensing since our unbalanced interferometer matches the interval of UWFBGs. The 3 m of spatial resolution of coherent detection and multiple simultaneous vibration sources locating can be realized based on OTDR. The enhanced signal to noise ratio (SNR) enables fast detection of distributed vibration without averaging. The fastest vibration of 25 kHz and the slowest vibration of 10Hz can be detected with our system successfully, and the linearity is 0.9896 with a maximum deviation of 3.46nε.