• Title/Summary/Keyword: Fiber-optic temperature sensor

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Thermo-optic Characteristics of Micro-structured Optical Fiber Infiltrated with Mixture Liquids

  • Wang, Ran;Wang, Yuye;Miao, Yinping;Lu, Ying;Luan, Nannan;Hao, Congjing;Duan, Liangcheng;Yuan, Cai;Yao, Jianquan
    • Journal of the Optical Society of Korea
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    • v.17 no.3
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    • pp.231-236
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    • 2013
  • We present both theoretically and experimentally the thermo-optic characteristics of micro-structured optical fiber (MOF) filled with mixed liquid. The performance of MOF depends on the efficient interaction between the fundamental mode of the transmitted light wave and the tunable thermo-optic materials in the cladding. The numerical simulation indicates that the confinement loss of MOF presents higher temperature dependence with higher air-filling ratios $d/{\Lambda}$, longer incident wavelength and fewer air holes in the cladding. For the 4cm liquid-filled grapefruit MOF, we demonstrate from experiments that different proportions of solutions lead to tunable temperature sensitive ranges. The insertion loss and the extinction ratio are 3~4 dB and approximate 20 dB, respectively. The proposed liquid-filling MOF will be developed as thermo-optic sensor, attenuator or optical switch with the advantages of simple structure, compact configuration and easy fabrication.

Measurement of Brillouin Backscattering for Distributed Temperature Sensor Applications

  • Kim, Su-Hwan;Kwon, Hyung-Woo;Kwon, Hyun-Ho;Jang, Hang-Seok;Kim, Jee-Hyun;Kang, Shin-Won
    • Journal of Sensor Science and Technology
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    • v.20 no.1
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    • pp.8-13
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    • 2011
  • We present measurements of the Brillouin frequency shift in an optical fiber using a 1550 nm distributed feedback laser diode(DFB-LD) as a light source. By modulating the probe light with an electro-optic modulator, we confirm the stimulated Brillouin gain spectrum(BGS) and spontaneous BGS using the coherent detection method. We also confirm the applicability of the technique to distributed temperature sensors that measure the change in Brillouin frequency shift due to temperature variations.

Analysis of Electromagnetic Radiation Hazard for Electro-explosive Device Using Fiber Optic Sensor (광섬유 센서를 이용한 EED 전자파 방사 위해도 분석)

  • 김응조;윤기은;윤태훈;김재창
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.9 no.6
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    • pp.725-734
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    • 1998
  • When the EED is exposed to the high power radiation, it is possible to verify systems survivability through measuring the induced current of EED. The usual method of performing a system level test is to replace the EED's with modified units from which the explosive charge has been removed and replaced with the fiber optic sensor. The thermal transient test was performed to obtain the temperature vs current characteristic curve for optical sensor installed in EED. The currents measured when the system is exposed to a known EME are compared to the proposed specfication about the EED and a decision is made on whether system is safe or not.

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Fiber Optic AC Voltage Sensor Using Fringe Counting (간섭무늬의 변화갯수 측정을 이용한 광섬유 교류전압센서)

  • 김봉규;김병윤;김만식
    • Korean Journal of Optics and Photonics
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    • v.5 no.1
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    • pp.158-165
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    • 1994
  • A fiber optic voltage sensor is demonstrated with a new signal processing scheme that displays the magnitude and the waveform of applied voltage with immunity from the signal frequency change. The sensor is based on a Mach-Zehnder interferometer with a PZT phase modulator as a sensing element. We observed a linear relationship between applied voltage and the number of fringe shift during a half cycle of the ac signal. The temperature dependence of the sensor output is experimentally evaluated over the temperature range from $-20^{\circ}C to 80^{\circ}C$. It is demonstrated that the detrimental polarization modulation effect can be overcome by using polarization maintaining fibers or a half-wave plate. plate.

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Development of Load Cell Using Fiber Brags Grating Sensors and Differential Method for Structural Health Monitoring (구조 건전성 모니터링을 위한 광섬유 브래그 격자 센서와 차동법을 적용한 로드셀 개발)

  • Kim, Dae-Hyun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.29 no.4
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    • pp.299-307
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    • 2009
  • Emerging fiber optic sensor technologies have shown great potential to overcome the difficulties associated with conventional sensors. Fiber optic sensors are immune to EM noise and electric shock and thus can be used in explosion-prone areas. Several kinds of fiber optic sensors have been developed over the last two decades to take advantage of these merits. There have also been many field applications of fiber optic sensors for structural health monitoring as NDT/HDE. However, very few sensors, particularly a load cell have been successfully commercialized. This Paper Presents a load cell using fiber Bra99 gra1ing (FBG) sensors. The shape of the load cell is a link type, and three FBG sensors are used for measuring strains at three different points. Especially, these strains are processed with a differential method in order to exclude common mode noise such as temperature. Moreover, the sensitivity, the linearity and the resolution of the load cell were successfully verified from the experiment of tension test.

Fiber-optic Temperature Sensor Using a Silicone Oil and an OTDR (OTDR을 이용한 실리콘 오일 기반의 광섬유 온도 센서)

  • Jang, Jae Seok;Yoo, Wook Jae;Shin, Sang Hun;Lee, Dong Eun;Kim, Mingeon;Kim, Hye Jin;Song, Young Beom;Jang, Kyoung Won;Cho, Seunghyun;Lee, Bongsoo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.11
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    • pp.1592-1597
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    • 2015
  • In this study, we developed a fiber-optic temperature sensor (FOTS) based on a silicone oil and an optical time domain reflectometer (OTDR) to apply the measurement of a coolant leakage in the nuclear power plant. The sensing probe of the FOTS consists of a silicone oil, a stainless steel cap, a FC terminator, and a single mode optical fiber. Fresnel reflection arising at the interface between the silicone oil and the single mode optical fiber in the sensing probe is changed by varying the refractive index of the silicone oil according to the temperature. Therefore, we measured the optical power of the light signals reflected from the sensing probe. The measurable temperature range of the FOTS using a Cu-coated silica fiber is from $70^{\circ}C$ to $340^{\circ}C$ and the maximum operation temperature of the FOTS is sufficient for usage at the secondary system in the nuclear power plant.

Spatial Reservoir Temperature Monitoring using Thermal Line Sensor (다중온도센서를 통한 입체적인 호소 온도모니터링 평가)

  • Hwang, Ki-Sup;Park, Dong-Soon;Jung, Woo-Sung
    • Proceedings of the Korea Water Resources Association Conference
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    • 2006.05a
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    • pp.1002-1006
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    • 2006
  • Temperature monitoring techniques per depth have been recognized as important information in the reservoir environmental issues. However, old measurement method by single temperature sensor and cable type has demerits not only for its limited measuring location but for its inconvenience of users. In this study, multi-channel temperature monitoring system was introduced and executed experiment for actual application feasibility evaluation. Both type of new techniques such as multi-channel addressable built-in temperature sensor and fiber optic multi sensor were tested in Daechung and Imha reservoir. As a result, it was proved that these kinds of temperature monitoring skills had very good performance and availability for a output of spatial, simultaneous thermal distribution focused on the user's convenience. And these measuring method and thermal data will be useful for providing basic information in a water resources investigation like reservoir stratification and environmental problems.

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A study of Fiber-Optic Voltage Sensor in a distribution automated switch (배전자동화 개폐기에서 광전압센서에 관한 연구)

  • 오상기;김요희;서승현;이희철;양승국
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2000.05a
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    • pp.493-496
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    • 2000
  • This study is about the design and fabrication of optical voltage sensor modules improved in the insulation reliability, where we adopted the space-division voltage system using the auxiliary electrodes to apply the uniform electric fields to the BSO, the device of which the polarization state varies with the variation of refractive index in the electric fields. We measured the output of fiber-Optic Voltage Sensors with the temperature changes in the thermostatic oven. And we measured the output of Fiber-Optic Voltage Sensors after setting its up in the disttibuion automated switch being apply 60Hz alternating voltage from 6.6kV to 17.BkV. In result, measured error characteristic is good, so we can judge it is applicable to the practical case

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A signal processing technique for interferometric fiber-optic sensors (간섭형 광섬유센서의 신호처리 기법)

  • 예윤해
    • Korean Journal of Optics and Photonics
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    • v.6 no.4
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    • pp.365-372
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    • 1995
  • A signal processing technique for interferometric fiber-optic sensors is proposed. It does not require a any special optic components such as phase modulator, $3times3$ couplers,to obtain the full sensitivity of the interferometer. Instead, it requires a reference interferometer for phase referencing and a reference mirror for intensity referencing, but intensity referencing can be done without using the r reference mirror. The new technique utilizes the frequency chirping of the laser diode to process t the sensor signal with both wide dynamic range and high sensitivity of the interferometer. It was a applied to an internal-mirrored FP interferometric temperature sensor to obtain the system noise of $4\times10^{-3\circ}C$ from I cm FP Interferometor sensor device.

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Measurement of Distributed Temperature and Strain Using Raman OTDR with a Fiber Line Including Fiber Bragg Grating Sensors (광섬유 브래그 격자 센서가 있는 광섬유 라인에 라만 OTDR을 이용한 분포 온도 및 변형률 측정 가능성에 대한 연구)

  • Kwon, Il-Bum;Byeon, Jong-Hyun;Jeon, Min-Yong
    • Journal of the Korean Society for Nondestructive Testing
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    • v.36 no.6
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    • pp.443-450
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    • 2016
  • In this study, we propose a novel fiber optic sensor to show the measurement feasibility of distributed temperature and strains in a single sensing fiber line. Distributed temperature can be measured using optical time domain reflectometry (OTDR) with a Raman anti-Stokes light in the sensing fiber line. Moreover, the strain can be measured by fiber Bragg gratings (FBGs) in the same sensing fiber line. The anti-Stokes Raman back-scattering lights from both ends of the sensing fiber, which consists of a 4 km single mode optical fiber, are acquired and inserted into a newly formulated equation to calculate the temperature. Furthermore, the center wavelengths from the FBGs in the sensing fiber are detected by an optical spectrum analyzer; these are converted to strain values. The initial wavelengths of the FBGs are selected to avoid a cross-talk with the wavelength of the Raman pulsed pump light. Wavelength shifts from a tension test were found to be 0.1 nm, 0.17 nm, 0.29 nm, and 0.00 nm, with corresponding strain values of $85.76{\mu}{\epsilon}$, $145.55{\mu}{\epsilon}$, $247.86{\mu}{\epsilon}$, and $0.00{\mu}{\epsilon}$, respectively. In addition, a 50 m portion of the sensing fiber from $30^{\circ}C$ to $70^{\circ}C$ at $10^{\circ}C$ intervals was used to measure the distributed temperature. In all tests, the temperature measurement accuracy of the proposed sensor was less than $0.50^{\circ}C$.