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Ultrasensitive refractive index sensor based on parallel-connected dual Fabry-Perot interferometers with Vernier effect
摘要： A kind of ultrasensitive refractive index sensor based on parallel-connected dual Fabry-Perot interferometers (FPIs) with Vernier effect is proposed and demonstrated. The open and closed cavity FPIs are used as the sensing and reference units, respectively. The Vernier effect is realized by superimposing the reflective comb spectra of the dual FPIs, which have slightly different free spectral ranges. The open groove of the open cavity FPI provides a convenient, efficient and economical method for filling in or draining out the cavity. The stability, repeatability and temperature response of the structures are investigated. Experimental results indicate that the proposed sensing structure features high sensitivity, good stability, quick and accurate measurement.
关键词： Refractive index sensing,Fabry-Perot interference,Vernier effect,Fiber-optic sensor
更新于2025-11-28 14:23:57
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Superstructure Fiber Bragg Gratings for Simultaneous Temperature and Strain Measurement
摘要： A new and simple fiber optic sensor based on a superstructure fiber Bragg grating (SFBG) for simultaneous temperature and strain measurement is proposed. The SFBG is a superimposed grating for which a long period fiber grating (LPG) and a fiber Bragg grating (FBG) is written in the same section of a Corning SMF-28 fiber. The reflection spectrum of the SFBG possesses two resonant peaks and a trough. By measuring the wavelength shift of the main resonant peak and the reflection power change of the trough, temperature and strain can be determined simultaneously. The accuracy of the sensor in measuring strain and temperature is estimated to be ±13.01 με in a range from 0 με to 1000 με and ±0.75 ℃ from 20 ℃ to 100 ℃, respectively.
关键词： CO2 laser,SFBG,simultaneous measurement of temperature and strain,fiber optic sensor
更新于2025-09-23 15:23:52
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[IEEE 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon) - Vladivostok, Russia (2018.10.3-2018.10.4)] 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon) - Modeling of the Magneto-Optical Channel of a Fiber-Optic Displacement Sensor
摘要： According to earlier studies conducted by the authors it was found that contactless fiber-optic sensors based on the magneto-optical Faraday effect (FOSF) in epitaxial films of iron garnet can be used for contactless monitoring of the status of control plate valves that regulate the flow of fire and explosion hazardous substances and operate over a wide temperature range. FOSF makes it possible to control the displacement and tilt angle of the valve regulating element (valve plate). However, at the moment there are no sufficiently accurate mathematical models for such FOSF. Studies have shown that the discrepancy between simulation results and experiments can reach 105%. The discrepancy between the results increases significantly when the FOSF is operated in a wide temperature range (from minus 196 to +80 °C). The low accuracy of the FOSF models does not make it possible to develop efficient means of compensating its intrinsic and complementary errors. The existing FOSF models are not sufficiently accurate, since they do not take into account: the distribution of the normal component of the magnetic field strength along the magneto-optical element (MOE) cross-section; the distribution of the optical radiation intensity along the MOE cross-section; optical absorption of the FOSF optical elements. According to the results of research carried out by the authors a set of mathematical models that takes into account the nonuniform distribution of the optical radiation intensity along the MOE cross-section, the nonuniform distribution of normal component of the magnetic field strength along the MOE cross-section, the optical absorption in FOSF optical elements and their temperature dependences was developed. This allowed us to significantly reduce the modelling error. The discrepancy between the results of mathematical modeling and experimental studies of FOSF prototypes does not exceed 7.2%.
关键词： control valve,contactless fiber optic sensor,mathematical model,fire and explosion safety,Faraday effect
更新于2025-09-23 15:23:52
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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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Vibration sensing based on macrobending loss in a standard single mode fiber loop structure
摘要： A new optical fiber sensor for vibration measurement has been proposed and demonstrated. This paper realizes vibration sensing based on the macrobending loss in a standard single-mode fiber loop. The experiments shows the suggested sensor enable us to measure multi-frequency vibrations with the resolution as high as 0.04 Hz. The crosstalk between temperature and vibration can be ignored because the macrobending loss is insensitive to the ambient temperature.
关键词： Bend loss,Vibration sensor,Fiber optic sensor
更新于2025-09-23 15:22:29
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Fiber Optic Sensors Based on Photoacoustic Effect for Rebar Corrosion Measurement
摘要： An all-optical ultrasound sensing system based on photoacoustic principle is developed to monitor and investigate the initiation of early stage steel rebar corrosion in real time. The ultrasound generator was developed by small size gold nanocomposites coated optical fibers to generate 8-MHz bandwidth signals. The ultrasound receiver was applied by a fiber Bragg grating sensor. This system was employed for the first time as a disruptive approach in order to replace the application of conventional electrical-based sensors due to their unique advantages including miniature size, lightweight, immunity to electromagnetic interference, resistance to corrosion, and distributed sensing capability. Accelerated corrosion tests were conducted on steel rebars to validate the developed sensing system. The obtained results indicated that the mass loss of corroded steel rebars was characterized by the centroid frequency shift of measured ultrasound signals. The correlation between the centroid frequency shift and the mass loss depicted an exponential relationship.
关键词： photoacoustic (PA) principle,fiber optic sensor (FOS),frequency shift,Corrosion monitoring
更新于2025-09-23 15:22:29
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Investigation of a low cost tapered plastic fiber optic biosensor based on manipulation of colloidal gold nanoparticles
摘要： We demonstrate a low cost Tapered Fiber Optic Biosensor (TFOBS) based on manipulation of colloidal gold nanoparticle in the evanescent field of tapered fiber. The sensor consists of a biconical tapered plastic optical fiber with colloidal gold nanoparticles coated on the tapered region. The strength of evanescent field absorption as a function of gold nanoparticle size is evaluated using Finite Difference Time Domain simulation. Simulation results suggest that in order to achieve maximum absorption in visible range of wavelength, the size of the gold nanoparticle should be in the range 3-4 nm. Gold nanoparticle of desired size is then synthesized and coated on the tapered region to fabricate a TFOBS. It is found experimentally that coating of gold nanoparticles enhances the fraction of light coming out to the cladding surface. This is explained as a consequence of local surface plasmonic resonance. The TFOBS is then tested for its sensing application to detect Bovine Serum Albumin. Level of detection of the proposed sensor is calculated and is found as 0.326gm/dL.As normal albumin level in healthy human blood serum is between 3.5 to 5.5gm/dL, the proposed TFOBS can be used as a low cost accurate albumin sensor.
关键词： Tapered Fiber Optic Sensor,Local Surface Plasmon Resonance,Manipulation of nanoparticle
更新于2025-09-23 15:22:29
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Precisely Automatic Time Window Locating for an Interferometric Fiber-Optic Sensor Array Based on a TDM Scheme
摘要： Interferometric fiber-optic sensors are often organized in the form of large-scale arrays by lending the technique of time division multiplexing (TDM) to reduce the system cost. Discriminating the time windows for different sensor units is the prerequisite to successfully demodulate the sensing message, but it traditionally calls for a very time-consuming manual calibration process. To combat this problem, a novel automatic time window locating method is proposed in this paper. It introduces the concept of shape function and carries out the cross-correlation operation between the shape function and the sensor signal. The shape function is defined as the function whose curve profile reflects the main data characteristics of the sensor signal. The time window information is then extracted from the correlation result. This whole process is carried out automatically by the interrogation controller of the sensor system without any manual intervene. Experiments are conducted to validate this method. The proposed method can greatly reduce the complexity of locating time windows in large-scale TDM sensor arrays, and make the practical use of the TDM scheme much more convenient.
关键词： fiber-optic sensor,interrogation controller,time division multiplexing (TDM),time window,cross correlation
更新于2025-09-23 15:22:29
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Optical Interferometry || Applications of Fiber-Optic Interferometry Technology in Sensor Fields
摘要： Optical interferometry as a precision metrology has been widely employed in many aspects for accurate measurements of various physical quantities. As an important branch of measurement technology, now the fiber-optic interferometry technology, based on fiber-optic and laser technologies, has been developed and widely applied in sensor fields for detections of various unknown or uncontrolled physical parameters. In this chapter, basic concepts of fiber-optic interferometry are presented and clarified. Also, three novel fiber-optic sensors, based on the optical interferometry technology and mainly used in the power industry for equipment failure monitoring, are demonstrated.
关键词： optical interferometry,fiber-optic sensor,fiber Bragg grating-based interferometer,interference fringe,laser
更新于2025-09-23 15:21:21
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Fiber Optic Fabry-Perot Pressure Sensor with Embedded MEMS Micro-Cavity for Ultra-High Pressure Detection
摘要： we demonstrate a fiber-optic Fabry-Perot pressure sensor with embedded MEMS micro-cavity for ultra-high pressure detection. The embedded type structure (ETS) is first proposed and analyzed to meet the requirements of ultra-high pressure detection. The geometry parameters of sensor have been optimized by analyzing mechanical and optical characteristics. From the analysis results based on the ETS, an ultra-high pressure sensor is fabricated and experimentally demonstrated for ultra-high pressure detection. The ultra-high pressure experiment illustrated response relationship between the absolute phase and pressure in the range of 2~120MPa, and full-scale errors less than 0.079%F.S. at room temperature. The other characteristics index of sensor, such as pressure sensitivity, hysteresis error, temperature’s influence factor are superior to rad/ ℃ . The transient response time of system is 0.27s. The sensor can be used for ultra-high pressure detections, which is necessary in deep-sea and oil exploration.
关键词： Pressure detection,Fabry-Perot,Fiber optic sensor
更新于2025-09-23 15:21:21