• Title/Summary/Keyword: fiber Bragg grating

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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.

Optical Acetylene Gas Detection using a Photonic Bandgap Fiber and Fiber Bragg Grating (광섬유 격자와 포토닉 밴드갭 광섬유를 이용한 아세틸렌가스 검출)

  • Lee, Yun-Kyu;Lee, Kyung-Shik
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.47 no.7
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    • pp.23-29
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    • 2010
  • We propose an optical gas sensor, which consists of a hollow core photonic bandgap fiber (HC-PBGF) and fiber Bragg grating (FBG), for the detection of acetylene gas. The gas detection scheme is uniquely characterized by modulating the Bragg wavelength of the fiber Bragg grating around a selected absorption line of gas filled in the photonic bandgap fiber. In the measurement, a 2m-long HC-PBGF and FBG with a Bragg wavelength of 1539.02nm were used. The FBG was modulated at 2Hz. We demonstrated that the optical fiber gas sensor was able to selectively measure the 2.5% and 5% of acetylene gases.

Health monitoring of carbon fiber-reinforced polymer composites in γ-radiation environment using embedded fiber Bragg grating sensors

  • Jing Zhong;Feida Chen;Yuehao Rui;Yong Li;Xiaobin Tang
    • Nuclear Engineering and Technology
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    • v.55 no.8
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    • pp.3039-3045
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    • 2023
  • Fiber-reinforced polymer (FRP) composites are considered suitable candidates for structural materials of spacecrafts due to their excellent properties of high strength, light weight, and corrosion resistance. An online health monitoring method for FRP composites must be applied to space structures. However, the application of existing health monitoring methods to space structures is limited due to the harsh space environment. Here, carbon fiber-reinforced polymer (CFRP) composites embedded with fiber Bragg grating (FBG) sensors were prepared to explore the feasibility of strain monitoring using embedded FBG sensors in γ-radiation environment. The analysis of the influence of radiation on the strain monitoring demonstrated that the embedded FBG can be successfully applied to the health monitoring of FRP composites in radiation environment.

Development of Tactile Force Sensor using Fiber Bragg Grating (광섬유 브래그 격자를 이용한 촉각 힘 센서의 개발)

  • Kim, Man-Sub;Lee, Jung-Ju
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.811-816
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    • 2004
  • The tactile force sensor was studied using Fiber Bragg Grating (FBG). The FBG is able to multiplex easily and is immune to electromagnetic environment. A sensor frame was designed to a cantilever beam type. Strain of a beam is related with the peak shift of a bragg wavelength. Finite Element Method (FEM) was used for getting an appropriate thickness from 0.2 mm to 0.3 mm thick. FEM results showed that 0.3 mm thick was suitable for the force range 10 N. The force resolutions of 0.039 N and 0.113 N were obtained with optical spectrum analyser and tunable Fabry-Perot filter, respectively.

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Sensitivity Improvement of Fiber Bragg Grating Temperature Sensor (광섬유격자 온도센서의 민감도 개선)

  • Kang, Han-Chul;Song, Min-Ho
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.26 no.3
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    • pp.40-45
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    • 2012
  • We substantially increased the temperature sensitivity of a fiber Bragg grating temperature sensor by gluing it onto a piece of bi-metal strip. The temperature-induced Bragg wavelength shift is increased upto 5 times more than that of the intrinsic FBG sensor by the strain effect from the deflected bi-metal. We showed the feasibility of the proposed sensor by comparing the temperature measuring experiments with those of the intrinsic FBG sensors. Also we measured temperature varying the length of the bi-metal pieces and analyzed the result effect of it.

Measurement of Material Properties of Composites for High Temperature using Fiber Bragg Grating Sensors (광섬유 브래그 격자 센서를 이용한 고온용 복합재의 물성 측정)

  • 강동훈;박상욱;김수현;김천곤;홍창선
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2003.04a
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    • pp.31-36
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    • 2003
  • Recently, composite materials are widely used for nozzle, pressure vessel, skins of satellite and many structures under condition of high temperature due to good thermal characteristics such as low CTE, heat-resistance, etc. Fiber optic sensors, especially FBG(fiber Bragg grating) sensors, can be a good counterproposal of strain gages for the measurement of material properties of composites under high temperature. In this research, T700/Epoxy specimens with embedded FBG sensors were fabricated and tested at the Instron with thermal chamber from room temperature to $400^{\circ}C$. The effects of embedding optical fiber on material properties were also verified. And, the experimental results were discussed and analyzed by microphotographs of the composite specimen.

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Absolute Strain Measurement Using Fiber Bragg Grating Sensor (광섬유 브래그 격자 센서를 이용한 절대 변형률 측정)

  • ;Lou-shuang
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.416-420
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    • 2002
  • This Paper describes a matched-filter type strain sensor system using optical fiber Bragg grating (FBG) sensor. Matched-filter type uses another wavelength-matched FBG filter to track wavelength shift in the FBG sensor. Filter FBG is attached on a fiber stretcher and stretched by PZT actuator. To overcome the nonlinearity and hysteresis of the PZT actuator that degrades system accuracy, a string resonator which can measure an absolute strain is employed. And the effect of vibration modes on string resonator is investigated particularly regarding its sensitivity and stability.

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Single-longitudinal-mode unidirectional fiber laser using fiber Bragg grating (광섬유 브래그 격자를 이용한 단일 종모드 단방향 광섬유 레이저)

  • 이정찬;전영민;김명욱;김봉규;이상배;김상국;최상삼;이상선
    • Korean Journal of Optics and Photonics
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    • v.10 no.3
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    • pp.233-236
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    • 1999
  • We have constructed a narrow-linewidth single-longitudinal-mode unidirectional $Er^{3+}$ -doped fiber laser using a fiber Bragg grating incorporated by a three port optical circulator with a compact configuration. Using a conventional delayed self-heterodyne detection technique with Mach-Zehnder interferometer a linewidth of 5 kHz was measured. In a single-longitudinal-mode operation, output power of up to 2.7 mW at 1548 nm were obtained for a launched pump power of 43 mW at 980 nm.

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Polarization-Diversity-Loop-Configuration-Based Fiber Filter Realizing Inline Conversion Between Transmission and Reflection Spectra of Fiber Bragg Grating (광섬유 브래그 격자의 투과 및 반사 스펙트럼간 동일 선로상 변환이 가능한 편광상이 배치구조 기반 광섬유 필터)

  • Jang, Wook;Lee, Yong-Wook
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.5
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    • pp.1-6
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    • 2011
  • By incorporating a polarization-diversity loop configuration (PDLC), we have demonstrated inline conversion between transmission and reflection spectra of a fiber Bragg grating (FBG) without reconfiguration of the fiber filter structure. The proposed apparatus consists of a polarization beam splitter, an FBG, and two quarter-wave plates (QWP's). The inline conversion operation between transmission and reflection spectra of the FBG was performed by proper adjustment of QWP's within the proposed filter. The band rejection ratio and side-mode suppression ratio in transmission and reflection modes of the fabricated filter were measured as ~17.0[dB] and ~16.4[dB], respectively.

Wavelength spacing tunable multi-wavelength Erbium-doped fiber ring laser (파장간격 가변형 다파장 어븀 첨가 광섬유 링 레이저)

  • Kim, Hwan;Jang, Hyun-Soo;Park, Kwang-No;Lee, Kyung-Shik
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.45 no.2
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    • pp.55-60
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    • 2008
  • Multi-wavelength Erbium-doped fiber(EDF) ring laser was developed by using a sampled fiber Bragg grating reflecting multiple wavelengths, which was formed by impressing periodical pressure on the outside of a fiber Bragg grating. The wavelength spacing was varied to 4.1nm, 1.41nm and 0.82nm, by pressing the grating with the pressure period $200{\mu}m$, $580{\mu}m$ and $1000{\mu}m$, respectively.