• 유공압시스템학회논문집
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• 제7권2호
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• pp.1-6
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• 2010

A new type fiber optic sensing system has been developed as a commercially available standard using the technique of hetero-core spliced fiber optic sensor, for the purposes of monitoring large scaled structures, preserving natural environments and measuring physical phenomenons. The sensing system has been tested and evaluated in a possible outdoor condition in view of the full scaled operation at actual sites to be monitored. Additionally, the developed system in this work conveniently provides us with various options of sensor modules intended to measure such physical quantities as displacement, distortion, pressure, binary states and liquid adhesion. The experiment study has been performed to examine the performance to a pseudo-cracking experiment in the outdoor situation, and to clarify temperature influences to the system in terms of the coupling of optical connectors and the OTDR stability. It has been verified that the sensing system is robust to the temperature change ranging from the general condition to the hard condition. Especially, in this study, the specification and performances of the pressure sensor have been demonstrated to show the capability of inspecting various physical quantities.

• 한국광학회지
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• 제8권5호
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• pp.410-414
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• 1997

Laser projection display(LPD)는 레이저를 이용한 full color의 대형화면을 구현하는 system이다. $TeO_2$와 $LiNbO_3$ 단결정을 음향광학 매질과 transducer로 사용하여 이 system에 쓰이는 영상 신호 처리용 음향광학변조기(Acousto Optic Modulator : AOM)를 제작하고 그 특성을 평가하였다. AOM은 transducer에서 발생된 초음파가 가장 효과적으로 음향광학 매질에 전달되도록 simulation한 후 제작하였으며 제작된 AOM은 특성평가와 더불어 설계값에 맞게 제작되었는가를 회절효율 측정을 통해 검증하였다. LPD System에 실장된 AOM의 회절효율은 85%이며 rise time은 41.5 ns이다.

• 조명전기설비학회논문지
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• 제29권8호
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• pp.76-82
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• 2015

A hybrid fiber-optic sensor system which combines fiber Bragg grating sensors and a Michelson interferometer has been constructed and evaluated for condition monitoring of large scale wind turbines. In order to measure multiple stresses applied to wind turbines such as strain, temperature and vibration, the system uses single broadband light source. It addresses both types of sensors, which simplifies the optical setup and enhances the cost-effectiveness of condition monitoring system. An athermal-packaged FBG is used to supply quasi-coherent light, of which coherence length is about 3.28mm, for the Michelson interferometer demodulation. Experimental results demonstrated that the proposed fiber-optic sensor system was capable of measuring strain and temperature with measurement accuracy of 1pm. Also 500~2000Hz vibration signals were successfully analyzed by applying FFT signal processing to interference signals.

• Journal of Biosystems Engineering
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• 제31권2호
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• pp.128-134
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• 2006

Frequent outbreaks of foodborne illness demand the need for rapid and sensitive methods for detection of these pathogens. Recent development of biosensor technology has a great potential to meet the need for rapid and sensitive pathogens detection from foods. An antibody-based fiber-optic biosensor and an automated reagents supply system to detect Listeria monocytogenes were developed. The biosensor for detection of Listeria monocytogenes in PBS and bacteria spiked food samples was evaluated. The automated reagents supply system eliminated cumbersome sample and detection antibody injection procedures that had been done manually. The biosensor could detect $10^4$ cfu/ml of Listeria monocytogenes in PBS. By using the fiber-optic biosensor, $2x10^8$ cfu/ml of Listeria monocytogenes in the food samples were detectable.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.203-206
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• 2003

Thermo-optic tunable filter, with 4-pairs of H/L layers for DBR, was designed and fabricated. The transmittance characteristics of the filter were measured. Additionally, heating system and temperature sensor system were used in order to observe property of the filter by thermo-optic effect. The tuning efficiency of the filter was measured to be 0.144nm/K$^{-1}$ showing the tuning range of 9.4nm for the temperature variation of 64.7$^{\circ}C$. Filter, lens and fiber were aligned by micro-optical bench.

• 한국정밀공학회지
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• 제21권5호
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• pp.142-148
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• 2004

In this paper, to detect exciting frequency on the latticed fence structure, fiber optic sensor using Sagnac interferometer was fabricated and tested. The latticed structure fabricated with dimension of 180 cm wide and 180 cm high, the optical fiber, 50 m in length, distributed and fixed on the latticed structure. Single mode fiber, a laser with 1,550 m wavelength, and $3{\times}3$ coupler were used. Excited vibration signal applied to the latticed structure from 200 Hz to 1 KHz. The detected optical signals were compared to the detected acceleration signals and analyzed on the time and frequency domain. Based on the experimental results, fiber optic sensor using Sagnac interferometer detected exciting frequency, effectively. This system can be applied to the structural health monitoring system.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2003년도 하계학술대회 논문집
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• pp.182-182
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• 2003

• 조명전기설비학회논문지
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• 제24권12호
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• pp.25-32
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• 2010

Compared to general lighting method, the lighting system that uses optic fiber can provide only the visible light of good quality to subject by eliminating ultraviolet ray and infrared ray. Thanks to this merit, it is possible to prevent the hard phenomenon of subject caused by ultraviolet ray and infrared ray and to provide the agreeable light environment. This study developed indoors illumination system of high color rendering on the basis of plastic optic fiber with excellent optical property and processing to substitute halogen lamp which has been used for excellent color rendering in spite of low efficiency and short life. Producing pilot product of the designed illumination system and evaluating the property of electric and optical property, ultraviolet ray radiation quantity and temperature property, this study verified the excellence of suggested lighting system of plastic optic fiber.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.111-114
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• 2003

A new monitoring system has been developed for in-situ and realtime measurement of ozone transport in unsaturated porous media using a fiber optic sensor. The calibration of the fiber optic transflection dip probe (FOTDP) system was successfully carried out at various ozone concentrations using a column with length of 30 cm and diameter of 5 cm packed with glass beads, which don't react with gaseous ozone. The breakthrough curves (BTCs) of ozone was obtained by converting the normalized intensity into ozone concentration. The FOTDP system reflected the ideal transport phenomena of gas phase ozone at various flow rates. The FOTDP system worked well for in-situ monitoring of gas phase ozone at various water saturations and in presence of SOM. However, the FOTDP system did not measure the ozone concentration at more than 70% water saturation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1887-1889
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• 1997

This paper reports the principle, design, configuration, and test results of the fiber optic security system using multimode fiber. In this system, optical fiber works as a sensing element. The length of sensing element may be from several meters to several killometers. Physical principle of this system is the dependence of interferometric pattern on the end of the fiber on mechanical perturbation in the area, where this fiber is situated. Near and far field patterns of the output light for multimode fiber are speckle pattern. A number of speckles on the fiber depends on mode numbers. Light intensity in each point of the fiber end depends on phase difference of modes. Finally we introduced a "Fiber Optic Security System based on Multimode" Fiber which we developed, it may be available in the field of the important area and building.