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High-precision FBG demodulation using amplitude ratio curve with sharp peak
摘要： For the fiber Bragg grating (FBG) sensor based on the reflection peak position searching demodulation algorithms, a key problem is that the demodulation precision of measurement signal is seriously limited by the full width half maximum (FWHM) of the FBG reflection spectrum. In this paper, in order to overcome this problem and enhance the measurement precision, we proposed a high-precision demodulation method based on amplitude ratio curve to instead of the FBG reflection spectrum, which can increase the sensing precision significantly. In this method, the Bragg wavelength of FBG is modulated periodically with a sinusoidal function to obtain a series of reflection spectra. Then at each wavelength the amplitude ratio between second harmonic frequency component and fundamental frequency component is calculated to create the amplitude ratio curve. Here, we present a comprehensive theoretical analysis and experimental demonstration to verify the advantages of this method. Comparing with the demodulation method based on the FBG reflection spectrum, the average maximum measure error (MME) of Bragg wavelength is reduced from ± 1.54 pm to ± 0.15 pm, which improved by 10.3 times. In addition, the influence of the modulation amplitude and sampling frequency on demodulation accuracy are also studied in this paper.
关键词： Amplitude ratio curve,High precision temperature measurement,Fiber Bragg grating
更新于2025-09-23 15:23:52
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Deformation sensing and electrical compensation of smart skin antenna structure with optimal fiber Bragg grating strain sensor placements
摘要： Skin antenna structure is a kind of multifunctional composite structure in which printed antennas are integrated. This paper proposes a new smart skin antenna structure with embedded fiber Bragg grating (FBG) strain sensors. Utilizing the measured strains from limited FBG strain sensors, the deformation shapes are reconstructed by using a strain–displacement transformation, and the deteriorated radiation patterns caused by the deformations are compensated by using a strain-electromagnetic coupling mode which is derived and validated for the first time in the paper. Moreover, a two-step sensor placement method considering the information redundancy is proposed to determine optimal FBG strain sensor locations. The comparisons show that the two-step sensor placement method is advantageous in terms of the sensor distribution and computational cost. The fabrication process of the smart skin antenna structure was presented, and an experimental system with optimal sensor placements was developed. The measured results demonstrate that the reconstructed shapes agree well with the real ones, and that the deteriorated radiating patterns were almost completely restored to the desired ones. The proposed smart skin antenna structure which can provide the electromagnetic receiving-sending, structural deformation monitoring and electrical correction functions has a potential application prospect in the future mobile vehicle.
关键词： Fiber Bragg grating,Deformation sensing,Electrical compensation,Smart skin antenna,Optimal sensor placement
更新于2025-09-23 15:23:52
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AIP Conference Proceedings [Author(s) 4TH ELECTRONIC AND GREEN MATERIALS INTERNATIONAL CONFERENCE 2018 (EGM 2018) - Bandung, Indonesia (27–28 July 2018)] - Design and analysis of fiber Bragg grating tunable filter utilizing thermal technique
摘要： In this paper a tunable filter based on fiber Bragg grating (FBG) utilizing thermal technique is theoretically investigated and experimentally validated. According to the results, a tuning range is achieved about 1.5 nm in C-band region. While, for L-band region the wavelength shift is slightly greater than in the C-band region about 1.6 nm. This shifting is due to changing in thermo-optic and thermal expansion of fiber, which causes changing in refractive index and then Bragg wavelength. The experimental validation is done at wavelength 1552.7 nm, the tunability is about 1.2428 nm when the temperature is varied from 21°C to 61°C.
关键词： thermal expansion,fiber Bragg grating,thermo-optic effect,thermal technique,tunable filter
更新于2025-09-23 15:23:52
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Fiber Bragg grating-based experimental and numerical investigations of CO <sub/>2</sub> migration front in saturated sandstone under subcritical and supercritical conditions
摘要： Carbon dioxide (CO2) can be at risk of leakage during its storage in deep saline aquifers due to stress field changes in the reservoir. The aim of this study was to investigate the effects of CO2 injection pressure on dynamic strain response of the reservoir and the CO2 migration process. A series of core flooding experiments was performed with the-state-of-art fiber Bragg grating sensors. The results show that the surface strain response was linearly correlated with CO2 injection pressure. Carbon dioxide migration velocity can be estimated from the strain response time differences among three gratings. The migration velocity of supercritical CO2 is higher than that of liquid CO2 but lower than gaseous CO2. Finally, numerical simulation was applied to model the CO2 migration process and the simulated values were compatible with those of experiments.
关键词： reservoir sandstone,core flooding,CO2 geological storage,CO2 migration front,fiber Bragg grating,strain response
更新于2025-09-23 15:23:52
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A novel fiber Bragg grating system for eye tracking
摘要： Eye movement evaluation is vital for diagnosis of various ophthalmological and neurological disorders. The present study proposes a novel, noninvasive, wearable device to acquire the eye movement based on a Fiber Bragg Grating (FBG) Sensor. The proposed Fiber Bragg Grating Eye Tracker (FBGET) can capture the displacement of the eyeball during its movements in the form of strain variations on a cantilever. The muscular displacement generated by the eyeball over the lower eyelid, by its swiveling action while moving the gaze on a target object, is converted into strain variations on a cantilever. The developed FBGET is investigated for dynamic tracking of the eye- gaze movement for various actions of the eye such as fixations, saccades and main sequence. This approach was validated by recording the eye movement using the developed FBGET as well as conventional camera-based eye tracker methodology simultaneously. The experimental results demonstrate the feasibility and the real-time applicability of the proposed FBGET as an eye tracking device. In conclusion, the present study illustrates a novel methodology involving displacement of lower eyelid for eye tracking application along with the employment of FBG sensors to carry out the same. The proposed FBGET can be utilized in both clinical and hospital environment for diagnostic purposes owing to its advantages of wear-ability and ease of implementation making it a point of care device
关键词： Eye Tracker,Fiber Bragg Grating Sensor,Eye muscular movement detection
更新于2025-09-23 15:23:52
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[IEEE 2018 3rd International Conference On Internet of Things: Smart Innovation and Usages (IoT-SIU) - Bhimtal (2018.2.23-2018.2.24)] 2018 3rd International Conference On Internet of Things: Smart Innovation and Usages (IoT-SIU) - Fiber Bragg Grating basedLandslide Early Warning System
摘要： Landslides are natural hazards which are known to cause loss of life and infrastructural damage. Landslide Early Warning System (LEWS) is intended to predict the occurrence of the landslide which provides ample time to initiate necessary protective measures. In the present study, a Fiber Bragg Grating (FBG) sensor based vibration sensor which can acquire the seismic vibrations is proposed as an LEWS. The proposed Fiber Bragg Grating Vibration Sensor (FBGVS) works on a specially designed cantilever structure, through which the seismic vibrations can be obtained in the form of strain variations on the cantilever. The strain variations over the cantilever will be acquired by the FBG sensor bonded over it. The cantilever is specially designed such that the strain sensitivity of the FBGVS is enhanced, by the appending of torsional strain along with the axial strain. Experimental trials have been carried out which prove the efficacy of the FBGVS to acquire the seismic vibrations. FBGVS acts as the sensing element for an IoT system to ensure the landslide warning signal is transmitted to all remote locations, effectively making an efficient LEWS.
关键词： Fiber Bragg grating sensor,Landslide Early Warning System,Fiber Bragg Grating Vibration Sensor
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 13th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS) - Singapore, Singapore (2018.4.22-2018.4.26)] 2018 IEEE 13th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS) - Temperature Sensor Based on Multimode Fiber Bragg Grating
摘要： A multi-layer film fiber Bragg grating (FBG) is used for high temperature measurement. In order to realize the temperature measurement in a wide dynamic range, a multi-layer film fiber Bragg grating (MFBG) is fabricated. Due to its multi-layer structure, the MFBG has been widely studied extensively for temperature measurement. Most of its operation principle is based on the variation analysis of the spectrum caused by temperature change. For measuring temperature, fiber Bragg grating (FBG) temperature sensor has been widely used due to its advantages of good insulation, light weight, low cost, compact structure, chemical property and ability to sense in harsh environment. However, the FBG has been widely studied extensively for temperature measurement. Most of its operation principle is based on the variation analysis of the spectrum caused by temperature change. For measuring temperature, fiber Bragg grating (FBG) temperature sensor has been widely used due to its advantages of good insulation, light weight, low cost, compact structure, chemical property and ability to sense in harsh environment. However, the FBG is difficult to couple with other optical devices, the MFBG has been used to measure the ambient temperature. In order to realize the temperature measurement in a wide dynamic range, a multi-layer film fiber Bragg grating (MFBG) is fabricated. Due to its multi-layer structure, the MFBG has been widely studied extensively for temperature measurement. The working principle is discussed and different reflection peaks are separated from the transmission spectrum. The experimental results show that the temperature response at different peaks is similar, and the optical fiber sensor has a great potential for temperature measurement.
关键词： fiber Bragg grating,multi-layer film,optical fiber sensor,temperature sensor
更新于2025-09-23 15:22:29
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A Rotation Independent In-Place Inclinometer/Tilt Sensor Based on Fiber Bragg Grating
摘要： The inclinometer is one of the most important instruments used in geotechnical engineering. The inclinometer is installed into a borehole to monitor the angle of inclination at regular intervals along the borehole to profile the land/soil displacement. In this paper, a novel design of an in-place inclinometer utilizing fiber Bragg grating (FBG) sensor technology is presented. The presented inclinometer is highly sensitive and has an angle measurement resolution of 0.006°. The conventional inclinometers may be twisted involuntarily due to the force that they experience during installation. This twisting may hamper the measurement accuracy of inclinometers. The performance of the proposed FBG-based in-place inclinometer is independent of twisting; hence, its accuracy remains intact even if it is twisted.
关键词： soil displacement/deformation,Borehole inclinometer,tilt sensor,fiber Bragg grating (FBG),land-slide monitoring,fiber optic sensor,in-place inclinometer
更新于2025-09-23 15:22:29
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Agar-coated fiber Bragg grating sensor for relative humidity measurements: influence of coating thickness and polymer concentration nm
摘要： The importance of humidity control is spreading through a broad spectrum of applications, from food and pharmaceutical industries to biomedical and chemical fields. During the last decades, the growing interest in fiber Bragg gratings (FBG) led to new approaches and applications for the humidity measurement by means of the deposition of hygroscopic materials on gratings. The influence of the coating material and its features such us coating thickness (tk) and concentration (wt%) on static and dynamic metrological properties have been investigated in the literature. In this study, four agar-coated FBG sensors for humidity measurements have been fabricated, and the influence of tk and wt% on the sensors’ sensitivity and response time has been experimentally assessed. Sensitivity increases with tk and wt%: for instance, at 1 wt% it was 0.0024 nm·%-1 and 0.0052 nm·%-1 for tk=87 μm and tk=212 μm, respectively. Results showed that also the response time increased with tk and wt%: for instance, at 1 wt% it was 56.7 s and 107.6 s for tk=87 μm and tk=212 μm, respectively.
关键词： Moisture sensitive polymers,Hygroscopic materials,Relative humidity sensing,Fiber Bragg grating sensors,Fiber optic sensors
更新于2025-09-23 15:22:29
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Experimental Research on Sensing Characteristics of Adhesive-encapsulated FBG under Alcohol-disinfection Environment
摘要： Fiber Bragg grating (FBG) has proven to be the most suitable sensing element for force feedback of surgical robots because of its special advantages such as small size and physical robustness. In current reports, researchers packaged FBGs in surgical instrument by attaching them to external surface or embedding into shaft grooves by using adhesive because its good liquidity and operability compared with other packaging methods such as metal package and glass solder package, and the adhesive is often without covering because strict space requirement of tiny surgical instruments. However, due to the need of repeated disinfection, surgical instruments have to be exposed to chemical disinfectant excessively, which may leads to chronic corrosion of adhesive, and thus influences the sensing characteristics of the integrated FBGs. To address this concern, this paper investigates the sensing characteristics of adhesive-encapsulated FBG under disinfection environment. We simulated a common disinfection environment by using 75% alcohol, and three adhesive-encapsulated FBGs were soaked in it for long term. The sensing performances of FBGs have been tested periodically and the experimental results demonstrate that the FBGs are available with good sensing characteristics within the first 50 days. While after 50 days, the sensing performances of the three FBGs become worse gradually, and finally the adhesive layers of the three FBGs completely detached from the specimen in the 75th day, 80th day and 95th day, respectively. We hope the investigation could provide valuable reference for better application of FBG in force feedback of surgical robots.
关键词： Fiber Bragg grating (FBG),robot sensing,force feedback,alcohol-disinfection environment,surgical robot
更新于2025-09-23 15:22:29