• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1985.01a
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• pp.21-23
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• 1985

By adding La$_2$O$_3$ to optical multicomponent glass composition, after making mother glass and core fiber that enable to enlarge the infrared transmittance region, then surveyed the optical properties. Through thermal analysis of the glass abstained by melt-quenching after selecting stable basic composition on devitrification and replace SiO$_2$ by 4-12wt% La$_2$O$_3$. As La$_2$O$_3$ increases up to l2wt% transition temperature, refractive index, density, deformation temperature increased, whereas thermal expansion coefficient decreased. As a result of inspectig transmittance in UV/VIS/IR region, visable region indicated the decrease of transmittance by increasing the La$_2$O$_3$ and transmittance region was enlarged by increasing the La$_2$O$_3$ in IR region. Also, fabricate core fiber at 820$^{\circ}C$ and severy the optical loss we could fact that La$_2$O$_3$ composition added 12wt% showed the minimum optical loss.

• Proceedings of the Optical Society of Korea Conference
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• 1990.02a
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• pp.232-236
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• 1990

Optical waveguide was fabricated in the soda lime glass substrate using rapid thermal method. A chirped grating having period variation of 0.41 - 0.51${\mu}{\textrm}{m}$ on this waveguide for WDM was made. And then, arranging input and output optical fiber, wavelength division multiplexer with 5 channels in short wavelength region was realized. Experiment result of this WDM showed that wavelength spacing, 3 dB bandwidth, insertion loss and crosstalk were 5nm, 4nm, 40dB and less than -10dB, respectively.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.260-261
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• 2002

파장 다중화(WDM) 방식의 광통신시스템에서 그림 1(a),(b)에 나타낸 바와 같이 한 쌍의 입출력 포트의 신호 방향을 바꾸는 광 가감기(Optical Add Drop Multiplexer)용의 2$\times$2 광 스위치가 사용된다 특히 멤스형 광 스위치는 삽입손실, 누화, 편광 및 파장 의존 손실 등이 낮아 많은 연구가 이루어지고 있다.(1-3) 광 스위치의 삽입손실을 낮추기 위해, 렌즈나 굴절률 맞춤액을 사용하는데, 광섬유를 정렬, 혹은 패키징할 때 렌즈나 맞춤액의 취급이 어렵다는 문제점이 있다. (중략)

• The Optical Journal
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• s.96
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• pp.55-59
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• 2005

광섬유격자 제조기술과 응용기술의 개발은 다양한 응용분야와 관련하여 광산업분야에 필수적인 요소이다. 또한 평판형 광도파로격자소자는 DWDM등 광전송 기술산업에 핵심적이고 원천적인 연구로서, WDM(Wavelength Division Multiplexing: 파중분할다중방식), Add/Drop Multiplexer 등 분야에 대한 응용기술연구가 필요하다. 광섬유 브래그격자(FBG: Fiber Bragg Grating)는 광통신 시스템의 핵심부품 중 하나이다. 제작공정의 특성상 다른 부품에 비하여 삽입손실(Insertion Loss)이 매우 작고, Fiber Laser, Laser wavelength stabilization, 광섬유 증폭기의 pump reflector, add/drop filter, optical circulator, 광증폭기의 이득평탄화 등 매우 다양한 응용분야를 가지고 있으며, 향후 수요시장이 대폭 증가할 것으로 기대된다.

• Journal of the Korean Graphic Arts Communication Society
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• v.29 no.3
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• pp.97-104
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• 2011

The storing ability of information of optical disks directly depends on the physical property of recording unit cells. It means that the degradation of optical disks ultimately causes the loss of the physical and chemical properties of recording unit cells and leads also information, too. We investigated the degradation and life time of optical disks which tell us the longevity of the preservation of information. Optical disks were aged using the accelerated aging system and studied by optical reflectivity spectroscopy and atomic force microscopy(AFM), and the preservation environment of electronic media in National central library of Korea also were analysed. Results show that the double reflective coated optical disks have good preservation of recording information but revealed some deformation of dye area in the AFM images. It means that we should include the mechanical and chemical degradation of the optical disks in the life time expectation evaluation.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1639-1641
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• 1997

In this study, We developed the 154kV optical fiber incorporated power cable which is combined optical fibers with conventional 154kV power cable. Also, we developed optical unit that optical fiber is inserted in stainless tube. The optical unit was tested, and we got good results enough to safe optical fibers. Also we put the optical fiber incorporated power cable to the test of electrical characteristics and optical characteristics, we knew that the electrical characteristics were the same characteristics as conventional 154kV power cable and the transmission loss change was almost zero. The method of optical unit connection was examined.

• Journal of the Optical Society of Korea
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• v.7 no.1
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• pp.28-33
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• 2003

We describe the optimal design and the fabrication of a 2$\times$2 port optical device based on the thin film filter (TFF), and also propose a 4-channel OADM module using these devices. The optical performance of the proposed OADM module is evaluated theoretically and experimentally, and is compared to that of typical OADM modules using 1$\times$2 port optical devices for 4, 8, 16 and 32 drop channels in optical transmission systems. Since the 2$\times$2 port optical device accomplishes the function of wavelength multiplexing and demultiplexing simultaneously in the proposed OADM module, the insertion loss of through channels can be improved by 1.2 dB compare to that of typical OADM modules using 1$\times$2 port optical devices. In addition, both the size and the price of the module can be reduced to 40~50%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.466-474
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• 2014

This paper presents the line contention avoidance experiments with an optical switch, which was selected based on the comparison analysis and evaluation of the various characteristics. For example, the function, structure, strengths and weaknesses of the optical switches. After considering the nonblocking, modularity, upgrade ability and optical power loss of the several kind of the switch fabrics, a switch was selected. The selected switch fabric by using wavelength converters was controlled to avoid contention of the optical lines. In this experiment shows an example of three cases. As a result of this experiment, optical signal shows a changed peek of optical power in output. By showing a peak it confirms that the contention was avoided. By analyzing of changed optical power according to the channel setting time and release time to control of the switch could be determined. If this analysis applied to the network design, economical and efficient structures can be formed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.903-910
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• 1998

Ti:LiNbO$_3$ optical waveguides have been fabricated by Ti-diffusion in wet oxygen atmosphere. The fabrication conditions of furnace temperature, diffusion time and bubbler temperature were 105$0^{\circ}C$, 8 hours and 9$0^{\circ}C$, respectively and Ti thickness was varied from 700$\AA$ to 1500$\AA$. In this paper, the nearfield patterns, mode sizes (hirizontal/vertical) and insertion loss of waveguides were discussed at wavelength 1550 nm ad function of Ti thickness. With the planar waveguide, the effective index change and diffusion depth were calculated at 632.8nm using the prism coupling method. From these results, the best Ti thickness in our conditions seems like to by 1200$\AA$~1300$\AA$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.12
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• pp.1266-1273
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• 1991

Attenuation losses and repeater spans of single-mode optical fibers installed in the long hual optical transmission line were measured and analyzed. The average loss including splicing points was appeared to be 0.55 0.05dB/km and 0.59 0.01dB/km at 1300nm and 1550nm, respectively, and showed lager value at 1550nm window, The cause of loss increase at 1550nm range from the OTDR measurement was due to the inappropriate treatment of extra length of fiber at the splicing points. And average repeater span of domestic long haul line was 24 7km and 90% of total sampled repeater spans was within 31 km.