• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.224-226
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• 2000

Consumer electronics is rapidly digitalized invoking the necessity of digital signal transmission. Moreover, even in consumer electronics, occasionally signal speed is over 1Gbps and long distance transmission(over 5 meters) is required. For these requirements, even though optical transmission is ideal, cost problem has blocked up its entrance to consumer market. However, inexpensive and high speed optical devices such as VCSEL, PIN or MSN PD with large detecting area and low capacitance and Plastic Optical Fiber have been developed so that optical solution can be compete with electrical one in consumer electronics.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.150-153
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• 2003

Longitudinal strains({$varepsilon}_x$) of the core and skin layers in glass fiber reinforced plastic(GFRP) cross-ply composite laminates have been studied using the embedded optical fiber sensor of totally-reflected extrinsic Fabry-Perot interferometer(TR-EFPI). Foil-type strain gauges bonded on both the upper and lower surfaces were used for the measurement of the surface strains. Both TR-EFPI sensor and strain gauge bonded on the specimen surface showed excellent agreement within -0.0086 ~ +0.0302% strain. It was shown that values of {$varepsilon}_x$ in the interior of the surface layer and the core layer measured by embedded TR-EFPI sensor was significantly higher than that of the specimen surface measured by strain gauges. The experimental results were ascertained with finite element analysis. Embedded TR-EFPI optical fiber sensor could measure accurately the internal strains which were different from the surface.

• Journal of Sensor Science and Technology
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• v.21 no.5
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• pp.367-373
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• 2012

We fabricated a fiber-optic alpha/beta detector, which is composed of a sensing probe, a plastic optical fiber, a photomultiplier tube, and a multichannel analyzer, to obtain the energy spectra of radioactive isotopes. As inorganic scintillators of a sensing probe, a ZnS(Ag) film was coupled with a $CaF_2$(Eu) crystal for alpha and beta spectroscopy. In this study, $^{210}Po$ and $^{90}Sr$ were used as alpha and beta sources, respectively, and we measured the radiation energy spectra using a fiber-optic alpha/beta detector to identify alpha and beta emitting radionuclides for nuclear medicine application. Also, the variations of energy spectrum were obtained according to the length of plastic optical fiber.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.11
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• pp.1083-1092
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• 2016

In this paper, the performance of the optical code-division multiple access (OCDMA) technology on a plastic optical fiber (POF) access network, which had received much attention due to its low weight, large core diameter, flexibility, easy installation, and especially its high bandwidth, is analyzed. Recently, POF was a very attractive candidate for transmission media in an access network based on OCDMA technology. But the conventional OCDMA system only allows finite units to transmit and access simultaneously according to the number of channels which are restricted by BER, and so, in this paper, to resolve this problem a novel multi-priority reservation protocol is also proposed. By using this reservation scheme and a distributed arbitration algorithm, channel collision and destination conflict could be avoided. And this protocol can efficiently support the transmission of multimedia messages that require the different time-delay. The network throughput and average delay using various system parameters have been investigated by numerical analysis and simulation experiments. These results shows that the multi-priority reservation protocol in this POF access network based on OCDMA technology is valid and efficient.

• Korean Journal of Optics and Photonics
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• v.22 no.1
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• pp.5-9
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• 2011

There are technical difficulties in measuring the numerical apertures of multi-mode gradient-index plastic optical fibers (GI-POFs) due to their strong speckle noise originating from dopants, non-uniformity of gradient-index profile, and multi-mode interference. Therefore, we propose a new method of obtaining the numerical aperture by controlling the size of the incident laser beam and measuring the numerical aperture of GI-POF. The results show that we can get a value for the numerical aperture of GI-POF very similar to that measured by the conventional method. We can also obtain the optimum launching condition of input beam and maximum coupling efficiency.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.32-33
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• 2001

근거리 통신망에서 데이터 전송량이 매우 증가함에 따라 근거리 통신에도 광통신을 적용하려는 연구가 활발히 진행 중이다. 광통신을 근거리 통신에 적용하려는 분야로는 랜, 댁내 망 (home network), 광 연결 (optical interconnect), 광 클럭 분배 (optical clock distribution) 등이 있다 그 중에 댁내 망의 경우 플라스틱 광섬유 (plastic optical fiber)를 이용하여 가정 내에 광통신을 적용하려는 연구가 진행 중이다. (중략)

• Design & Manufacturing
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• v.17 no.3
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• pp.28-33
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• 2023

The conventional FRP (Fiber Reinforced Plastic) manufacturing process used thermoset resins for ease of molding but faced the issue of non-recyclability. To address these shortcomings, a new process utilizing thermal plastic resin was developed. However, due to the high viscosity of thermal plastic resin, problems such as fiber deformation and a reduced fiber volume fraction occurred during the high-temperature, high-pressure process. In this study, to overcome the limitations of the conventional process, fiber-reinforced composite materials were manufactured through in-situ polymerization using PLA (Poly L-Lactide) resin in the VA-RTM (Vacuum Assistance Resin Transfer Molding) process. The fiber volume of the produced specimens was calculated, and resin impregnation and porosity were confirmed through optical microscopy. Additionally, molecular weight analysis using GPC (Gel Permission Chromatography) demonstrated improvements over the conventional process and emphasized the essential requirement of temperature control.

• Proceedings of the Optical Society of Korea Conference
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• 2008.07a
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• pp.311-312
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• 2008

• Korean Journal of Optics and Photonics
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• v.21 no.1
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• pp.16-20
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• 2010

In this study, we have fabricated a fiber-optic dosimeter using an organic scintillator and a plastic optical fiber. The dosimeter measure skin dose and percentage depth dose in a build-up region for an incident high energy photon beam. The scintillating light generated in the organic sensor probe embedded in a solid water phantom is guided by 30 m plastic optical fiber to a light-measuring device such as a PMT or an electrometer. In addition, using a fiber-optic dosimeter or a GAFCHROMIC EBT film, skin dose and percentage depth dose in the build-up region are measured and compared.

• Korean Journal of Optics and Photonics
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• v.21 no.1
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• pp.26-32
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• 2010

Line lamps, which utilize leaky optical fibers based on periodic bending of plastic optical fibers, are proposed. The LED-optical fiber coupler, the key component of the line lamp, is designed and analyzed. The analysis by the Monte Carlo photon simulation method has shown that the optical coupling efficiency is affected rather sensitively by $\theta_w$, the slanting angle of the reflecting cup sidewall and $\rho_{ref}$, the reflectivity of the reflecting cup. The optical coupling efficiency of the coupler reaches the maximum when $\theta_w$ is about $60^{\circ}$, which is significantly larger than $\theta_w=45^{\circ}$, the typical sidewall slanting angle of the reflecting cup adopted in most LED lamps. When the reflectivity of the reflecting cup is above 0.8, the optical coupling efficiency is larger than 80%, which is the typical efficiency to be achieved in LD-optical fiber coupler.