• 제목/요약/키워드: FBG(Fiber Bragg Grating)

검색결과 288건 처리시간 0.026초

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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    • 제25권5호
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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.

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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    • 제47권7호
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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.

Humidity Sensor Using Polyimide Film Coated Fiber Bragg Grating (폴리이미드가 코팅된 광섬유 브래그 격자를 이용한 습도센서)

  • Jae Chang Yang;Gun Pyo Kim;Kwang Taek Kim
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • 제36권6호
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    • pp.594-597
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    • 2023
  • We have proposed and demonstrated a fiber optic RH (relative humidity) sensor based on fiber Bragg grating covered with a polyimide film. As the polyimide film absolves the moisture in the air, its volume expands. As a result, the grating period of the FBG (fiber Bragg grating) covered with a polyimide film becomes wide and the Bragg wavelength is shifted. The sensor is implemented by fixing a 30 ㎛ thickness polyimide film on the surface of an optical fiber grating using an adhesive, and the characteristics of the device according to humidity are analyzed. The fabricated FBG RH sensor showed a high sensitivity of 0.0186 nm/RH% and a wide measurement range from 30% to 90%. The influence of environmental temperature on the characteristics of the RH sensor was also measured and analyzed. The feasibility of commercialization is presented.

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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    • 제9권4호
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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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Strain Transmission Characteristics of Packaged Fiber Bragg Grating Sensors for Structural Health Monitoring

  • Cho, Sung-In;Yoo, Seung-Jae;Kim, Eun-Ho;Lee, In;Kwon, Il-Bum;Yoon, Dong-Jin
    • Journal of the Korean Society for Nondestructive Testing
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    • 제30권3호
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    • pp.236-243
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    • 2010
  • Fiber Bragg grating(FBG) sensor arrays can be used to monitor the mechanical behavior of the large composite structures such as wind turbine rotor blades and aircrafts. However, brittle FBG sensors, especially multiplexed FBG sensors are easily damaged when they are installed in the flexible structures. As a protection of brittle FBG sensors, epoxy packaged FBG sensors have been presented in this paper. Finite element analysis and experiments were performed to evaluate the effects of adhesives, packaging materials and the bonding layer thickness on the strain transmission. Two types of epoxy were used for packaging FBG sensors and the sensor probes were attached with various bonding layer thickness. It was observed that thin bonding layer with high elastic modulus ratio of the adhesive to packaging provided good strain transmission. However, the strain transmission was significantly decreased when elastic modulus of the adhesive was much lower than the packaged FBG sensor probe's one.

Performance Evaluation of A Tunable Dispersion Compensator based on Strain-Chirped Fiber Bragg Grating in a 40 Gb/s Transmission Link

  • Kim, Chul-Han;Bae, Jun-Key;Lee, Kwan-Il;Lee, Sang-Bae
    • Journal of the Optical Society of Korea
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    • 제12권4호
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    • pp.244-248
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    • 2008
  • We have evaluated the performance of strain-chirped fiber Bragg grating (FBG) based tunable dispersion compensator in a 40 Gb/s transmission link. In our proposed compensator, the value of dispersion could be changed from -353 ps/nm to -962 ps/nm by adjusting the rotation angle of the metal beam on which the FBG was mounted. In order to evaluate the effect of ripples in reflectivity and variations in passband of the FBG based dispersion compensator, transmission performance has been measured with our tunable dispersion compensator. Error-free transmission of a 40 Gb/s non-return-to-zero (NRZ) signal over conventional single-mode fiber (SMF) was achieved.

Dispersion Compensation in the Optical Fiber Transmission system using the Fiber Bragg Grating (FBG를 이용한 광 파이버 분산 보상에 관한 연구)

  • 신희성;홍성철;손용환;이종윤;이창원;정진호
    • Proceedings of the IEEK Conference
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    • 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
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    • pp.81-84
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    • 2001
  • We propose the cascade FBG(Fiber Bragg Grating)s to compensate the dispersion, discuss the dispersion characteristics of such cascaded FBGs, compare with the single FBG dispersion compensator. For these, we theoretically consider the sencond- and third-order group-velocity dispersion(GVD) in the single fiber grating using plane wave solution and the coupled mode equation. We also theoretically find the group-velocity dispersion in the cascaded fiber gratings from the results in the single fiber grating and present the optimum disign data of the cascaded FBGs dispersion compensator in the N-channel WDM system through the numerical simulation.

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Detection of Hydrogen Gas Dissolved in Insulation Oil Based on Palladium-coated Fiber Bragg Grating (팔라듐이 코팅된 광섬유 격자를 이용한 절연유속의 용존 수소가스 검출)

  • Kim, Kwang Taek;Choi, Nu ri;Baik, Se-Jong
    • Journal of Sensor Science and Technology
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    • 제27권6호
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    • pp.403-406
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    • 2018
  • We have investigated a fiber-optic sensor for detecting the hydrogen gas dissolved in insulation oil based on a palladium (Pd)-coated fiber Bragg grating (FBG). As the palladium absorbs the hydrogen gas dissolved in the insulation oil, its volume expands and the Bragg wavelength shifts to a longer wavelength. The experimental results showed that the Bragg wavelength of FBG increased to 70 nm when the concentration of hydrogen dissolved in the insulation oil was 409 ppm.

A Walking Vibration Sensing System using a Fiber Bragg Grating Sensor (광섬유 브래그 격자 센서를 이용한 보행 진동 측정 시스템에 관한 연구)

  • Kim, Jaeki;Yeom, Sanghun;Lee, Seoksoon
    • Journal of Aerospace System Engineering
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    • 제11권1호
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    • pp.22-27
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    • 2017
  • In this paper, a walking vibration sensing system (WVS system) using a Fiber Bragg Grating sensor (FBG sensor) is proposed. The seismic part of the FBG sensor was redesigned for sensitivity enhancement. The external excitation was assumed to be the walking cycle of an adult male. The FBG seismic sensor was redesigned using CATIA and ABAQUS such that the sensor's first mode natural frequency is 3.5 Hz (which is a value near the external excitation frequency). Compared with existing walking vibration sensing systems, this newly created system improves sensitivity 15 times. It is also suitable for intrusion detection applications.

Cure Monitoring of Epoxy Resin by Using Fiber Bragg Grating Sensor (광섬유 브래그 격자 센서를 이용한 에폭시 수지의 경화도 모니터링)

  • Lee, Jin-Hyuk;Kim, Dae-Hyun
    • Journal of the Korean Society for Nondestructive Testing
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    • 제36권3호
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    • pp.211-216
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    • 2016
  • In several industrial fields, epoxy resin is widely used as an adhesive for co-curing and manufacturing various structures. Controlling the manufacturing process is required for ensuring robust bonding performance and the stability of the structures. A fiber optic sensor is suitable for the cure monitoring of epoxy resin owing to the thready shape of the sensor. In this paper, a fiber Bragg grating (FBG) sensor was applied for the cure monitoring of epoxy resin. Based on the experimental results, it was demonstrated that the FBG sensor can monitor the status of epoxy resin curing by measuring the strain caused by volume shrinkage and considering the compensation of temperature. In addition, two types of epoxy resin were used for the cure-monitoring; moreover, when compared to each other, it was found that the two types of epoxy had different cure-processes in terms of the change of strain during the curing. Therefore, the study proved that the FBG sensor is very profitable for the cure-monitoring of epoxy resin.