• Title, Summary, Keyword: multiplexing fiber Bragg grating

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Hydrogen Sensor Based on Palladium-Attached Fiber Bragg Grating

  • Lee, Sang-Mae;Sirkis, Jim-S.
    • Journal of the Optical Society of Korea
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    • v.3 no.2
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    • pp.69-73
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    • 1999
  • This paper demonstrated the performance of a palladium wire hydrogen sensor based on a fiber Bragg grating as a means of developing a quasi-distributed hydrogen sensor network capable of operating at cryogenic temperatures. The new approach employing a fiber Bragg grating based palladium hydrogen sensor described in this study is advantageous over other traditional hydrogen sensors because of the multiplexing capability of fiber Bragg gratings. The sensitivity of the hydrogen sensor at room temperature is approximately 2.5 times that of the hydrogen sensor at cryogenic temperatures.

Implementation of an Interrogator for the Operationand Measurement of Fiber Bragg Grating Multiplexing Sensor Probes (FBG 다중화 센서 탐촉자 구동 및 측정을 위한 인터로게이터 설계 제작)

  • Kim, Ji-Dea;Lee, Dong-Ju
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.23 no.2
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    • pp.199-205
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    • 2014
  • This research focuses on the development of an interrogator that operates and measures fiber Bragg grating(FBG) multiplexing sensor probes for accurate-measurement of the blade deflection in a wind power generator. We designed and fabricated an optical source and spectrum module for the interrogator. Additionally, we verified the wavelength repeatability within 0.001 nm and the wavelength stability within 1 pm of the optical source, and we experimentally determined that the wavelength scanning range was about 44.4 nm. The FBG sensor with 2 nm resolution can be extended to a performance-efficient system that measures more than 20 sensors. The implemented interrogator has 0.141 nm wavelength variations corresponding to an ambient temperature range of $0^{\circ}C$ to $70^{\circ}C$. The measurement error can be easily reduced by employing a temperature compensation algorithm. In this study, we quantitatively confirmed the accuracy and operating stability of the interrogator.

The Improvement of Survivability of Fiber Brags Grating Sensors Embedded into Filament Wound Pressure Tanks (필라멘트 와인딩된 복합재료 압력탱크에 삽입된 광섬유 브래그 격자 센서의 생존율 향상)

  • Kang, D. H.;Park, S. W.;Park, S. O.;Kim, C. G.
    • Composites Research
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    • v.18 no.5
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    • pp.1-8
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    • 2005
  • Among many fabrication methods of composite materials, filament winding is the most effective method for fabricating axis-symmetric structures such as pressure tanks and pipes. Filament wound pressure tanks are under high internal pressure during the operation and it has the complexity in damage mechanisms and failure modes. For this reason, it is necessary to monitor the tank through its operation as well as whole fabrication process. A large number of sensors must be embedded into multi points of the tank from its fabrication step for monitoring the whole tank. Fiber optic sensors, especially fiber Bragg grating(FBG) sensors are widely used for various applications because of good multiplexing capabilities. However, we need to develop the embedding technique of FBG sensors into harsh inner environment of the tank far the successful embedment. In this paper, we studied the embedding technique of a number of FBG sensors into filament wound pressure tanks considering multiplexing.

Fabrication of Fiber Bragg gratings using a tension controller for broad wavelength linewidth (반사 파장 선폭 확장을 위해 장력 조절기를 적용시킨 광섬유 브래그 격자(Fiber Bragg grating) 제작 기술)

  • Choi, Bo-Hun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.2
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    • pp.350-356
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    • 2012
  • The tension effect on fiber Bragg gratings was analyzed and the linearity of 1.24 nm/10kpsi was obtained when Bragg wavelength was varied within 3 nm by applied tension. Using tension control method, different center wavelength fiber Bragg grating(FBG) were fabricated by only single period phase mask. These serially connected four FBGs showed the transmission spectrum of 1.5 nm linewidth as a 3 dB bandwidth which was twice that of a conventional FBG.

The Optical Add-Drop Multiplexer for DWDM Using Fiber Bragg Grating (FBG를 이용한 DWDM용 광 Add-Drop 다중화기에 관한 연구)

  • 손용환;신희성;허주옥;장우순;정진호
    • Proceedings of the IEEK Conference
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    • pp.237-240
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    • 2001
  • Dense Wavelength division multiplexing(DWDM) lightwave system requires multiplexer, demultiplexer and optical filter. In this paper, thus, we propose the Add-Drop Mux/Demux based on a Mach-Zehnder interferometer(MZI) with fiber Bragg grating(FBG). The Add-Drop Mux/Demux using FBG and MZI is able to minimize system and reduce weight. We also analyze output characteristics of Add-Drop Mux/Demux and present the optimum design data through the computer simulation.

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A study on the multi-point signal detection, using Passive band-pass filter in FBG Hydrophone (FBG(Fiber Bragg Grating) Hydrophone에서 Passive Band-Pass Filter를 사용한 다중점 신호 검출에 관한 연구)

  • Kim, Kyung-Bok;Kwack, Kea-Dal
    • Journal of Sensor Science and Technology
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    • v.9 no.4
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    • pp.307-315
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    • 2000
  • To set up the arrays system of FBG(Fiber Bragg Grating) Hydrophone sensor and realize the multi-point signal detection for the wide scope underwater, using WDM(Wavelength Division Multiplexing) method and Passive band-pass filter system, underwater acoustic signal detection of the newly designed two FBG Transducers is successfully experimented. As a result of the experiment, it was possible each signal with different frequent signals is detected for the multi-point up to 1.3KHz in underwater. We can, therefore, prove the possibility on the system design of Hydrophone sensor arrays, using the newly made FBG Transducers.

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Spectrum analysis of the FBG sensor signal and location determination of FBG sensor into the $H_2$ pressure vessel (해석적인 기법을 통한 FBG 센서의 스펙트럼 분석 및 수소고압용기의 센서 삽입위치 결정)

  • Park, S.O.;Kim, C.U.;Park, J.S.;Kim, C.G.
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.25-28
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    • 2005
  • The optical fiber is known for the proper sensor which can accomplish the structural health monitoring, Fiber Bragg Grating sensors are being studied more than any other fiber optic sensors due to good multiplexing capabilities. But because the signal stability of FBG sensors can be influenced by the strain gradient, it needs to analyze signal of FBG sensors. Particularly acoording to strain gradient induced by structural geometry or cracks, the spectrum peak of the FBG sensor signal can be split easily. In this paper, the spectrum analysis of the FBG sensor signal was performed and the region of embedment of FBG sensors was determined in $H_2$ pressure vessel by numerical method.

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Multi-Point Optical Fiber Grating Strain Sensor System (광섬유 격자 다중화 스트레인 센서 시스템)

  • Lee, Yong-Wook;Jung, Jae-Hoon;Chung, Seung-Hwan;Lee, Byoung-Ho;Kim, Nam-Sik
    • Journal of the Korean Society for Nondestructive Testing
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    • v.21 no.2
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    • pp.147-151
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    • 2001
  • An optical fiber sensor is capable of nondestructive measurement of a structure and it has an advantage of the immunity to electromagnetic interference because light is not affected by electromagnetic wave. In addition, if optical fibers are buried in an object like a concrete, this sensor tan analyze defects and physical status of the object without disassembling it. Especially, the fiber Bragg grating sensor is a promising optical fiber sensor capable of nondestructive test of such an object. A fiber Bragg grating has the characteristics of reflecting or blotting light of a specific wavelength. If we apply physical quantity like strain to the fiber Bragg grating, the center wavelength of the reflected light is shifted and then we can find the physical quantity applied to the fiber Bragg grating by measuring the center wavelength shift of the reflected light. The fiber Bragg grating sensor capable ot static and dynamic strain measurement is being used in health-monitoring of buildings, structures, etc. Recently increasing is interest in dynamic strain measurement inevitable to the civil structures such as roads and bridges. In this study we implemented the optical fiber sensor system which can measure dynamic strain at multiple points using Fabry-Perot wavelength demodulation. And we measured the static and dynamic strain using this sensor system with a test structure(cantilever). Measurement results were similar to those obtained with the conventional electrical measurement methods.

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Measurement of Pile Load Transfer using Optical Fiber Sensors (광섬유 센서에 의한 말뚝 하중전이 측정)

  • 오정호;이원제;이우진
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.397-404
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    • 1999
  • It is essential to measure load transfer mechanism of pile to check the appropriateness of assumptions made for design purpose and to continuously monitor the behavior of pile foundation. Through many attempts to monitor the behavior of super-structure in civil engineering area using several optical fiber sensors have been made, application of optical fiber sensor technology on pile foundation has not been tried up to now. Load transfer of model piles during compression loading was measured by optical fiber sensors and compared with the measurement by strain gauges. Fiber Bragg Grating(FBG) sensor system was used since it has many advantages, such as easy multiplexing, high sensitivity, and simple fabrication. Besides the model pile tests, uniaxial tension test of steel bar and compression tests of mortar specimen were carried out to evaluate the performance of FBG sensors in embedded environments. The shift of refilming wavelength due to the strain in FBG sensor is converted to the strain at sensor location and the dependence between them is 1.28 pm/${\mu}$ strain. FBG sensors embedded in model pile showed a better survivability than strain gauges. Measured results of load transfer by both FBG sensors and strain gauges were similar, but FBG sensors showed a smoother trend than those by strain gauge. Based on the results of model pile test, it was concluded that the use of FBG sensor for strain measurement in pile has a great potential for the analysis of pile load transfer.

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Investigation of smart multifunctional optical sensor platform and its application in optical sensor networks

  • Pang, C.;Yu, M.;Gupta, A.K.;Bryden, K.M.
    • Smart Structures and Systems
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    • v.12 no.1
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    • pp.23-39
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    • 2013
  • In this article, a smart multifunctional optical system-on-a-chip (SOC) sensor platform is presented and its application for fiber Bragg grating (FBG) sensor interrogation in optical sensor networks is investigated. The smart SOC sensor platform consists of a superluminescent diode as a broadband source, a tunable microelectromechanical system (MEMS) based Fabry-P$\acute{e}$rot filter, photodetectors, and an integrated microcontroller for data acquisition, processing, and communication. Integrated with a wireless sensor network (WSN) module in a compact package, a smart optical sensor node is developed. The smart multifunctional sensor platform has the capability of interrogating different types of optical fiber sensors, including Fabry-P$\acute{e}$rot sensors and Bragg grating sensors. As a case study, the smart optical sensor platform is demonstrated to interrogate multiplexed FBG strain sensors. A time domain signal processing method is used to obtain the Bragg wavelength shift of two FBG strain sensors through sweeping the MEMS tunable Fabry-P$\acute{e}$rot filter. A tuning range of 46 nm and a tuning speed of 10 Hz are achieved. The smart optical sensor platform will open doors to many applications that require high performance optical WSNs.