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Using a Fiber Loop and Fiber Bragg Grating as a Fiber Optic Sensor to Simultaneously Measure Temperature and Displacement  [PDF]
Yao-Tang Chang,Chih-Ta Yen,Yue-Shiun Wu,Hsu-Chih Cheng
Sensors , 2013, DOI: 10.3390/s130506542
Abstract: This study integrated a fiber loop manufactured by using commercial fiber (SMF-28, Corning) and a fiber Bragg grating (FBG) to form a fiber optic sensor that could simultaneously measure displacement and temperature. The fiber loop was placed in a thermoelectric cooling module with FBG affixed to the module, and, consequently, the center wavelength displacement of FBG was limited by only the effects of temperature change. Displacement and temperature were determined by measuring changes in the transmission of optical power and shifts in Bragg wavelength. This study provides a simple and economical method to measure displacement and temperature simultaneously.
Down-hole Seismic Survey System with Fiber-optic Accelerometer Sensor for 3-Dimensions Vertical Seismic Profile
3维VSP光纤检波器井下地震采集系统

ZOU Qi-lin,WANG Li-wei,PANG Meng,TU Dong-sheng,ZHANG Min,LIAO Yan-biao,
邹琪琳
,王利威,庞盟,屠东升,张敏,廖延彪

光子学报 , 2008,
Abstract: A down-hole seismic survey system that can be applied in three dimensions vertical seismic profile (VSP) detection in petroleum exploration is demonstrated. The results of experiments show that the system has a dynamic measurement range of 80dB (ratio of maximum to minimum value) and the total delay for signal collection,process and communication is less than 200ms @ 2k bit sample rates. An array consisting of six fiber-optic accelerometers (receivers) is applied in this system. Each receiver is comprised of three fiber-optic Michelson interferometers. High-speed DSP chips are employed to realize the PGC demodulation and other algorithms to obtain the seismic information. Multi-ARM CPUs are introduced into the system to design the fiber-optic accelerometer array controller and the receiver array local bus. The design and experiments of the system are given in this paper in detail.
Analysis of a distributed fiber-optic temperature sensor using single-photon detectors  [PDF]
Shellee D. Dyer,Michael G. Tanner,Burm Baek,Robert H. Hadfield,Sae Woo Nam
Physics , 2011, DOI: 10.1364/OE.20.003456
Abstract: We demonstrate a high-accuracy distributed fiber-optic temperature sensor using superconducting nanowire single-photon detectors and single-photon counting techniques. Our demonstration uses inexpensive single-mode fiber at standard telecommunications wavelengths as the sensing fiber, which enables extremely low-loss experiments and compatibility with existing fiber networks. We show that the uncertainty of the temperature measurement decreases with longer integration periods, but is ultimately limited by the calibration uncertainty. Temperature uncertainty on the order of 3 K is possible with spatial resolution of the order of 1 cm and integration period as small as 60 seconds. Also, we show that the measurement is subject to systematic uncertainties, such as polarization fading, which can be reduced with a polarization diversity receiver.
Double-Ended Calibration of Fiber-Optic Raman Spectra Distributed Temperature Sensing Data  [PDF]
Nick van de Giesen,Susan C. Steele-Dunne,Jop Jansen,Olivier Hoes,Mark B. Hausner,Scott Tyler,John Selker
Sensors , 2012, DOI: 10.3390/s120505471
Abstract: Over the past five years, Distributed Temperature Sensing (DTS) along fiber optic cables using Raman backscattering has become an important tool in the environmental sciences. Many environmental applications of DTS demand very accurate temperature measurements, with typical RMSE < 0.1 K. The aim of this paper is to describe and clarify the advantages and disadvantages of double-ended calibration to achieve such accuracy under field conditions. By measuring backscatter from both ends of the fiber optic cable, one can redress the effects of differential attenuation, as caused by bends, splices, and connectors. The methodological principles behind the double-ended calibration are presented, together with a set of practical considerations for field deployment. The results from a field experiment are presented, which show that with double-ended calibration good accuracies can be attained in the field.
Development of a 2-Channel Embedded Infrared Fiber-Optic Temperature Sensor Using Silver Halide Optical Fibers  [PDF]
Wook Jae Yoo,Kyoung Won Jang,Jeong Ki Seo,Jinsoo Moon,Ki-Tek Han,Jang-Yeon Park,Byung Gi Park,Bongsoo Lee
Sensors , 2011, DOI: 10.3390/s111009549
Abstract: A 2-channel embedded infrared fiber-optic temperature sensor was fabricated using two identical silver halide optical fibers for accurate thermometry without complicated calibration processes. In this study, we measured the output voltages of signal and reference probes according to temperature variation over a temperature range from 25 to 225 °C. To decide the temperature of the water, the difference between the amounts of infrared radiation emitted from the two temperature sensing probes was measured. The response time and the reproducibility of the fiber-optic temperature sensor were also obtained. Thermometry with the proposed sensor is immune to changes if parameters such as offset voltage, ambient temperature, and emissivity of any warm object. In particular, the temperature sensing probe with silver halide optical fibers can withstand a high temperature/pressure and water-chemistry environment. It is expected that the proposed sensor can be further developed to accurately monitor temperature in harsh environments.
Fiber optic distributed temperature sensing for the determination of the nocturnal atmospheric boundary layer height
C. A. Keller, H. Huwald, M. K. Vollmer, A. Wenger, M. Hill, M. B. Parlange,S. Reimann
Atmospheric Measurement Techniques (AMT) & Discussions (AMTD) , 2011,
Abstract: A new method for measuring air temperature profiles in the atmospheric boundary layer at high spatial and temporal resolution is presented. The measurements are based on Raman scattering distributed temperature sensing (DTS) with a fiber optic cable attached to a tethered balloon. These data were used to estimate the height of the stable nocturnal boundary layer. The experiment was successfully deployed during a two-day campaign in September 2009, providing evidence that DTS is well suited for this atmospheric application. Observed stable temperature profiles exhibit an exponential shape confirming similarity concepts of the temperature inversion close to the surface. The atmospheric mixing height (MH) was estimated to vary between 5 m and 50 m as a result of the nocturnal boundary layer evolution. This value is in good agreement with the MH derived from concurrent Radon-222 (222Rn) measurements and in previous studies.
Fiber optic distributed temperature sensing for the determination of the nocturnal atmospheric boundary layer height
C. A. Keller,H. Huwald,M. K. Vollmer,A. Wenger
Atmospheric Measurement Techniques Discussions , 2010, DOI: 10.5194/amtd-3-2723-2010
Abstract: A new method for measuring air temperature profiles in the atmospheric boundary layer at high spatial and temporal resolution is presented. The measurements are based on Raman scattering distributed temperature sensing (DTS) with a fiber optic cable attached to a tethered balloon. These data were used to estimate the height of the stable nocturnal boundary layer. The experiment was successfully deployed during a two-day campaign in September 2009, providing evidence that DTS is well suited for this atmospheric application. Observed stable temperature profiles exhibit an exponential shape confirming similarity concepts of the temperature inversion close to the surface. The atmospheric mixing height (MH) was estimated to vary between 5 m and 50 m as a result of the nocturnal boundary layer evolution. This value is in good agreement to the MH derived from concurrent Radon-222 (222Rn) measurements and in previous studies.
Calibrating Single-Ended Fiber-Optic Raman Spectra Distributed Temperature Sensing Data  [PDF]
Mark B. Hausner,Francisco Suárez,Kenneth E. Glander,Nick van de Giesen,John S. Selker,Scott W. Tyler
Sensors , 2011, DOI: 10.3390/s111110859
Abstract: Hydrologic research is a very demanding application of fiber-optic distributed temperature sensing (DTS) in terms of precision, accuracy and calibration. The physics behind the most frequently used DTS instruments are considered as they apply to four calibration methods for single-ended DTS installations. The new methods presented are more accurate than the instrument-calibrated data, achieving accuracies on the order of tenths of a degree root mean square error (RMSE) and mean bias. Effects of localized non-uniformities that violate the assumptions of single-ended calibration data are explored and quantified. Experimental design considerations such as selection of integration times or selection of the length of the reference sections are discussed, and the impacts of these considerations on calibrated temperatures are explored in two case studies.
Anomalous Fiber Optic Gyroscope Signals Observed above Spinning Rings at Low Temperature  [PDF]
M. Tajmar,F. Plesescu,B. Seifert
Physics , 2008, DOI: 10.1088/1742-6596/150/3/032101
Abstract: Precision fiber optic gyroscopes were mounted mechanically de-coupled above spinning rings inside a cryostat. Below a critical temperature (typically <30 K), the gyroscopes measure a significant deviation from their usual offset due to Earth's rotation. This deviation is proportional to the applied angular ring velocity with maximum signals towards lower temperatures. The anomalous gyroscope signal is about 8 orders of magnitude smaller then the applied angular ring velocity, compensating about one third of the Earth rotation offset at an angular top speed of 420 rad/s. Moreover, our data shows a parity violation as the effect appears to be dominant for rotation against the Earth's spin. No systematic effect was found to explain this effect including the magnetic environment, vibration and helium gas friction suggesting that our observation is a new low temperature phenomenon. Tests in various configurations suggest that the rotating low temperature helium may be the source of our anomalous signals.
Investigation on Output Properties of Optic-Fiber Temperature Sensor
光纤温度传感器输出特性研究

LEI Xiao-mei,CHEN Chang-le,
雷晓梅
,陈长乐

光子学报 , 2007,
Abstract: A new optic-fiber temperature sensor based on the spectrum absorption characteristic of semiconductor used to measure the environmental temperature is designed.The sensor is composed of GaAs semiconductor platelets,transmitted probe configuration and POF beam guarding.And it is simple in structure,low in cost and reliable.Its output properties are investigated through experimental method by using the different light source.The relations between the light source spectrum property and the sensor temperature-measuring rang and its sensitivity are analyzed according to the experimental data.At last an improved opinion using two-wavelength compensating system to solve the problems of the disturbance effect and instability in the sensor is indicated.
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