• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.3
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• pp.214-217
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• 2003

본 연구에서는 IPA(isopropyl alcohol)를 분해물질로 선정하여 플라스틱 광섬유(Plastic Optical Fiber, POF)에 TiO₂ 를 코팅하여 오염물질을 분해하였다. P-25가 코팅된 POF의 표면은 유기계, 무기계, 유ㆍ무기 바인더를 사용한 것 모두 깨끗하였고, 무기계 바인더를 사용하여 코팅한 POF는 부착력이 현저히 떨어졌다. IPA분해 결과, 무기계 바인더를 사용한 경우, 다른 종류의 바인더와는 다르게 IPA의 초기농도 값이 매우 작게나왔는데 이러한 결과는 반응기에 주입된 IPA가 평형이 될 때까지 기다리는 동안 흡착이 일어났기 때문으로 생각된다. 유기계 바인더를 사용하여 코팅한 POF는 IPA 분해 효율이 매우 저조하였고 유ㆍ무기 바인더를 사용하여 코팅한 POF의 IPA분해 효율은 우수하였다. P-25와 IPA의 분해 효율이 우수한 유ㆍ무기 바인더의 비율을 10 : 10, 10 : 8, 10 : 6, 10 : 4, 10 : 2로 바꾸어 IPA를 분해한 결과, P-25와 유 ㆍ 무기 바인더의 비율이 10 : 2 일 매 IPA 분해 효율이 가장 우수하였다. 또한 P-25와 코팅액 제조 시 희석제로 사용되는 에탄올의 질량비를 1 : 7, 1 : 11, 1: 15로 바꾸어 IPA를 분해한 결과, P-25와 에탄올의 비율이 1 : 15일 때 IPA분해 효율이 가장 우수하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.3B
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• pp.53-64
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• 2005

Rapid growth of digitalization in telecommunication and broadcasting and remarkable enhancement in broadband and high speed transmission capability of media raised a problem of integrating communication and broadcasting. In order to implement this, the government has selected construction of Broadband Convergence Network (BcN) as a main new growth engine of the country. The BcN will be realized based on FTTH and Broadband Home Network (BHN) will be implemented through this solution. Transfer rate and bandwidth required for the BcN to be constructed aiming at integration of communication and broadcasting will be specified and the performance of basic transmission media, the plastic optical fiber, will be discussed in order to present its appropriateness.

• Journal of Sensor Science and Technology
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• v.25 no.4
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• pp.280-284
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• 2016

For an arc-flash protection system, the selection of arc-flash sensor in implementation is largely dependent on the coverage area and the spatial resolution. Typically, a point sensor is used to accurately measure an arc event within a very narrow region; whereas, a loop or a line sensor can cover several electrical compartment at the same time, but with a poor resolution. In this work, a novel scheme for an arc-flash sensor was developed by making use of the transmission loss of plastic optical fibers (POFs) to cover a broad range with a high spatial resolution. By relating the amplitude ratio of the arc-signals at the ends of the POF with the arc-location, arc events could be located with a resolution of ~5 cm within a spatial range of 10 m, which has not been reported yet.

• Journal of the Optical Society of Korea
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• v.9 no.3
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• pp.99-102
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• 2005

Directional couplers of gradient-index plastic optical fibers were fabricated and characterized. In particular, we have employed a core-facet technique to make the directional couplers, which require mechanical side polishing and linkage. We have measured insertion loss, excess loss, and coupling ratio of the fabricated couplers as a function of polishing depth and coupling length. We found that polishing depth of $\~300{\mu}m$ and coupling length of $\~35mm$ are optimum conditions for minimizing the insertion and excess losses and for achieving 1: 1 coupling ratio.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.151-152
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• 2003

전보[1]에서 PMMA 코어 플라스틱 광섬유의 클래드 재료로 사용하기 위하여 MMA/불소계메타크릴레이트(FAMA) 공중합체를 제조하고 FAMA 종류 및 함량에 따른 굴절률, 내열성의 변화를 살펴보았다. FAMA의 함량이 증가함에 따라 굴절률은 효과적으로 낮출 수 있었으나 유리전이온도와 계면접착력은 감소하여 내열성 및 PMMA와의 계면 접착력을 향상시킬 수 있는 새로운 화학구조의 클래드 재료 설계가 필요하였다. (중략)

• Nuclear Engineering and Technology
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• v.52 no.8
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• pp.1689-1696
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• 2020

In this study, we developed a fiber-optic humidity sensor (FOHS) system for the monitoring and detection of coolant leakage in nuclear power plants. The FOHS system includes an FOHS, a spectrometer, a halogen white-light source, and a Y-coupler. The FOHS is composed of a humidity-sensing material, a metal tube, a multi-mode plastic optical fiber, and a subminiature version A (SMA) fiber-optic connector. The humidity-sensing material is synthesized from a mixture of polyvinylidene fluoride (PVDF) in dimethyl sulfoxide (DMSO) and hydroxyethyl cellulose (HEC) in distilled water. We measured the optical intensity of the light signals reflected from the FOHS placed inside the humidity chamber with relative humidity (RH) variation from 40 to 95%. We found that the optical intensity of the sensing probe increased linearly with the RH. The reversibility and reproducibility of the FOHS were also evaluated.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3206-3212
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• 2023

We developed a miniaturized multi-dimensional radiation sensor system consisting of an inorganic scintillator array and plastic optical fibers. This system can be applied to remotely obtain the radioactivity distribution and identify the radionuclides in radioactive waste by utilizing a scanning method. Variation in scintillation light was measured in two-dimensional regions of interest and then converted into radioactivity distribution images. Outliers present in the images were removed by using a digital filter to make the hot spot location more accurate and cubic interpolation was applied to make the images smoother and clearer. Next, gamma-ray spectroscopy was performed to identify the radionuclides, and three-dimensional volume scanning was also performed to effectively find the hot spot using the proposed array sensor.

• Journal of Sensor Science and Technology
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• v.21 no.4
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• pp.287-292
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• 2012

A fiber-optic radiation sensor was fabricated using a sensing probe, a plastic optical fiber, a photomultiplier tube, and a multichannel analyzer for gamma-ray spectroscopy. As an inorganic scintillator of the sensing probe, a LYSO crystal was used. In this study, we obtained the relationship between the photon counts of the fiber-optic radiation sensor and the activity of the radioactive isotope. In addition, the gamma-ray energy spectra were also measured using a fiber-optic radiation sensor to discriminate species of gamma-ray emitters.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11A
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• pp.1053-1058
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• 2006

In this paper, We proposed a efficient OSA(Optical Sub-Assembly) packaging method in use 1.31/1.49um bi-directional hybrid-integrated PLC chip for low-cost OSA in optical access network system applications as GE-PON in FTTH. Fabricated OSA with passive optical fiber alignment and nonhermetic plastic package method and measured optical coupling efficiency and electric-optical characteristics. Its performance is feasible to satisfy the GE-PON ONU specifications with the results as less than 0.5dB coupling losses within 40um alignment of z-axis and less than -24dBm sensitivity. It also has good temperature characteristics to sustain optical output power more than 1.5mW and 10dB extinction ratio, less than 0.3dB tracking error.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.291-292
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• 2009

Refractive index monitoring using U-shaped POF (Plastic optical fiber) in the sugar solution and salt solution were performed. The various bending losses of U-shaped POF due to the environmental refractive index changes of the measurand solution. The loss increases according to the amounts of solute in the solution which causes the refractive index change in the solution.