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Fiber laser based on a fiber Bragg grating and its application in high-temperature sensing
摘要: A fiber laser based on an FBG fabricated by femtosecond laser and a Sagnac loop as cavity mirrors is demonstrated. The fiber laser can work stably as a temperature sensor at 1000 ℃ after the FBG was annealed at 1100 ℃. The wavelength of the fiber laser had a quadratic dependence on temperature from room temperature to 1000 ℃. The temperature–wavelength had a good linear relationship from 300 ℃ to 1000 ℃. Its sensing sensitivity was about 15.9 pm/℃.
关键词: Optical fiber lasers,Fiber Bragg gratings,High temperature sensors
更新于2025-11-28 14:23:57
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Organic Field-Effect Transistor Based Ultrafast, Flexible, Physiological Temperature Sensors with Hexagonal Barium Titanate Nanocrystals in Amorphous Matrix as Sensing Material.
摘要: Organic field-effect transistors (OFETs) with hexagonal barium titanate nanocrystals in amorphous matrix (h-BTNC) as one of the bilayer dielectric system have been fabricated on a highly flexible 10 μm thick polyethylene terephthalate (PET) substrates. The device current and mobility remains same upto a bending radius of 4mm that make it suitable for wearable e-skin applications. h-BTNC films found to be highly temperature sensitive and the OFETs designed based on this material showed ultra-precession (~4.3 mK), low power (~ 1μW at 1.2 V operating voltage), ultrafast response (~24 ms) in sensing temperature over a range from 20 °C to 45 °C continuously. The sensors are highly stable around body temperature and work at various extreme conditions, such as under water, solutions of different pH as well as of various salt concentrations. These properties make this sensor very unique and highly suitable for various healthcare and other applications, where in a small variation of temperature around this temperature range is required to be measured at an ultra-fast speed.
关键词: low power OFETs,electronic skin,temperature sensors,organic field-effect transistors,flexible sensors,healthcare sensors
更新于2025-09-23 15:23:52
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Feasibility of 4H-SiC p-i-n Diode for Sensitive Temperature Measurements between 20.5 K and 802 K
摘要: For the first time, we report on the performances of 4H-SiC pin-diode temperature sensors for operating temperatures between 20.5 K and 802 K. In this huge temperature range three ranges of performance were identified with the limit temperatures at 78.2 K and 176.3 K. In each of these ranges a different dominant current transport mechanism is shown and in the manuscript a detailed analysis and discussion is reported. The sensor performances were extracted from VD-T characteristics at different fixed ID values. In particular, at ID=1 μA and in the temperature range between 78.2 K and 802 K, we found a sensor sensitivity of 2.3 mV/K up to 3.4 mV/K with a rms temperature error, eT, of less than 4.2 K and the sensor shows an excellent linearity – quantified by the coefficient of determination R2 higher than 0.9993. For even lower temperatures (below 78.2 K), low measurement currents like 10 nA are required leading to a sensitivity of 5.8 mV/K, but a lower linearity (R2=0.9095) and a rms temperature error of 9.7 K which makes the sensor only partially usable in the temperature range between 20.5 K and 78.2 K. Finally, the sensor performances are compared to other state-of-the-art solutions.
关键词: Semiconductor device modelling,Cryogenic temperatures,Temperature sensors,4H-Silicon Carbide device,High temperatures,Semiconductor p-i-n diodes
更新于2025-09-23 15:22:29
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Discerning Localized Thermal Heating from Mechanical Strain Using an Embedded Distributed Optical Fiber Sensor Network
摘要: Prior research has demonstrated that distributed optical fiber sensors (DOFS) based on Rayleigh scattering can be embedded in carbon fiber/epoxy composite structures to rapidly detect temperature changes approaching 1000°C, such as would be experienced during a high energy laser strike. However, composite structures often experience mechanical strains that are also detected during DOFS interrogation. Hence, the combined temperature and strain response in the composite can interfere with rapid detection and measurement of a localized thermal impulse. In this research, initial testing has demonstrated the simultaneous response of the DOFS to both temperature and strain. An embedded DOFS network was designed and used to isolate and measure a localized thermal response of a carbon fiber/epoxy composite to a low energy laser strike under cyclic bending strain. The sensor interrogation scheme uses a simple signal processing technique to enhance the thermal response, while mitigating the strain response due to bending. While our ultimate goal is rapid detection of directed energy on the surface of the composite, the technique could be generalized to structural health monitoring of temperature sensitive components or smart structures.
关键词: smart structures,distributed optical fiber sensors,temperature sensors,structural health monitoring,high energy radiation,polymer matrix composites,strain sensors,strain compensation
更新于2025-09-23 15:21:01
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Highly Linear and Stable Flexible Temperature Sensors Based on Lasera??Induced Carbonization of Polyimide Substrates for Personal Mobile Monitoring
摘要: Wearable on-skin electronic devices that can monitor temperature in real time are of significant interest for personalized mobile health monitoring. Here, a flexible temperature sensor directly patterned by laser-induced carbonization on Kapton polyimide films integrated with flexible printed circuit boards is reported. The proposed sensor design possessing high resistance values exhibits high-linear and stable response to temperatures when integrated with flexible printed circuit boards (FPCBs) to enable continuous monitoring. The anisotropic conductive film bonding technique is used to obtain the stable real-time monitoring data under various complex environments. The sensor integration with a wearable patch based FPCB establishes conformal contacts with human skin and allows wireless sensing capabilities smoothly in real time. This kind of approach can enable multifunctional sensors to be directly laser patterned on FPCBs without any additional interfacing.
关键词: real-time monitoring,FPCB,laser-induced carbonization,temperature sensors,biomedical devices
更新于2025-09-23 15:21:01
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Temperature Sensing Characteristics and Long Term Stability of Power LEDs Used for Voltage vs. Junction Temperature Measurements and Related Procedure
摘要: A detailed study about the direct measurement of junction temperature TJ of off-the-shelf power light emitting diodes (LED) is presented. The linear dependence on temperature of the voltage drop across the device terminals at a constant current is in particular exploited and fully characterized, in the temperature range from T = 35 ?C to 135 ?C, with tests repeated at one thousand different probe currents. The accurate experimental data, obtained on several LED samples bearing two different part numbers, are reported, showing that they exhibit a high degree of linearity in wide current ranges, a circumstance that allows for a fast and reliable calibration as sensors. The measurement error is also fully characterized in terms of repeatability and stability over time, with measurements repeated after 600, 900, 1200 and 1800 hours of applied electro-thermal stress, demonstrating that the relevant sensor parameters stabilize after a few hundred hours of operation. A full set of parameters is provided for the two device models, allowing the direct use of each LED for the self-monitoring of the junction temperature and ensure compliance with their safe operating area over time. Moreover, a procedure and a simple circuit for the real time measurement of TJ , while the LED is on, are presented. The procedure does not require a stable current source, and relies instead on the application of a sub-threshold current ramp for such a short time that the change in the output light is not perceived by human eyes.
关键词: junction temperature,diode sensors,light emitting diodes,temperature sensors,LED
更新于2025-09-19 17:13:59
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[IEEE 2019 2nd International Colloquium on Smart Grid Metrology (SMAGRIMET) - Split, Croatia (2019.4.9-2019.4.12)] 2019 2nd International Colloquium on Smart Grid Metrology (SMAGRIMET) - Fiber Optic Sensor Cable Based on Hollow Capillary Tube with Three Tightly Encapsulated Optical Fibers
摘要: Fiber optic sensor cable technology is relatively new field that combines a set of scientific and technical disciplines in a special way in order to meet industrial standards. In this paper we discuss one particular design for multipurpose and configuration multivalent optical fiber sensing. It has the potential to integrate more detection and measurement techniques in one cable body and this, in turn, largely contributes to installation cost optimization and directly impacts investment plans and industrial success. The article presents also a unique high-pressure high temperature lab facility conceptualized and constructed for testing and evaluation of this and similar optical fiber sensor cables.
关键词: fiber optic measurements,OFDR,acoustic sensors,BOTDA,BOTDR,DAS,Brillouin effect,optical fiber,pressure sensors,fully distributed optical fiber sensor,monitoring systems,strain sensors,temperature sensors,OTDR
更新于2025-09-16 10:30:52
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Mid-infrared sensing properties of a plasmonic metal-insulator-metal waveguide with a single stub including the defects
摘要: A highly sensitive surface plasmon polariton (SPP) based sensor with a simple structure that composes of a metal-insulator-metal waveguide with a single stub including several silver nanorod defects, is designed and numerically investigated using finite element method for the applications of refractive index sensors and temperature sensors. The simulation results show that the existence of silver nanorod defects in the single stub have a great influence on the sensitivity performance, which provides an additional degree to manipulate the system response in the nanometer scale. The refractive index sensitivity can be reached as high as 5140 nm/RIU (RIU is refractive index unit) and the temperature sensitivity is about 2.05 nm/0C, which can be further improved by varying the length of stub (h), radius of defect rod (r) and the number of defects (N) in the stub. The sensing characteristics of the proposed simple structure would pay the way for highly integrated optical circuits for designing nanoscale refractive index sensors and temperature sensors with the single stub including the defects.
关键词: integrated optical circuits,refractive index sensors,silver nanorod defects,metal-insulator-metal waveguide,temperature sensors,surface plasmon polariton,finite element method
更新于2025-09-12 10:27:22
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Highly Sensitive Temperature Sensing Performance of a Microfiber Fabry-Perot Interferometer with Sealed Micro-Spherical Reflector
摘要: A temperature probe has been proposed by inserting a microfiber taper into a silica hollow core fiber with a microsphere end. The sealed air cavity in the microsphere and the inserted microfiber acted as the two reflectors of a Fabry-Perot interferometer, respectively. The contribution of both microfiber diameter and cavity length on the interference spectra was analyzed and discussed in detail. The temperature change was experimentally determined by monitoring the wavelength location of the special resonance dip. By filling the air cavity with poly-dimethylsiloxane (PDMS), a high temperature sensitivity of 3.90 nm/°C was experimentally demonstrated. This temperature probe with the diameter of 150 μm and length of 10 mm will be a promising candidate for exploring the miniature or implantable sensors.
关键词: temperature sensors,fiber sensors,integrated optics,microfiber
更新于2025-09-11 14:15:04
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[IEEE 2018 IEEE International Instrumentation and Measurement Technology Conference (I2MTC ) - Houston, TX, USA (2018.5.14-2018.5.17)] 2018 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) - Experimental evaluation of low-cost interrogation techniques for FBG sensors
摘要: In this paper, the experimental investigation of two simple, cost-effective interrogation techniques based on optical power measurement for fiber Bragg gratings (FBG) sensors are presented. The first technique proposed employs each channel of a CWDM demultiplexer as an edge filter to modulate the optical power reflected by each sensing FBG, allowing for an array of FBG sensors to be interrogated simultaneously, sharing the same broadband light source (BLS) and interrogation system. In the second technique, the optical power reflected by a single sensing FBG is modulated directly by the transmission spectrum of the BLS, allowing for a simpler interrogation system. Both techniques rely on a compact, low-cost optoelectronic circuit developed for the acquisition and measurement of the optical signals. With resolutions of up to 1.26 pm for a mechanical strain sensor, or an equivalent 0.09 oC for a temperature sensor, experimental results show that both techniques are accurate, reliable, and suitable for applications where the only requirement is the monitoring of the spectral position of the Bragg wavelength (λB) of the FBG sensors, replacing more expensive, general-purpose FBG interrogators available in the market. Since FBGs are passive, lightweight, and provide dielectric insulation, the proposed techniques are suitable for temperature or mechanical strain measurements in hostile environments in which the use of conventional sensors must be avoided, such as in high voltage power lines and cables, and explosive atmospheres.
关键词: fiber Bragg gratings,temperature measurement,temperature sensors,optical fiber sensors
更新于2025-09-10 09:29:36