• 한국인쇄학회지
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• 제30권3호
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• pp.77-88
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• 2012

In this report, we performed the measurements of physical properties of optical discs as a long term preservation electronic recording device and showed how to improve the preservation method of them. We collect the 1,993 optical discs from the archives of the National Archives of Korea and tested various measurements. We used DVDT-SD4 equipment to measure the quality of data, deformation of disc, the various writing strategy and manufacturer derives, which can be happened in optical discs by physical factors. We found that th quality of data are closely related with write strategy between discs and drives. This relation gives us information about data quality in optical discs for long term preservation that can be obtained from the state between empty discs and optical drives before recording. Thus, the initial selection of optimal discs and drives is critical for long term recording data preservation and the data quality after long time preservation will not be much different from that of the initial ones.

• 한국정밀공학회지
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• 제18권4호
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• pp.46-54
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• 2001

Technology of data storage device has developed noticeably as demands and needs of new media increase, Huge data can be conveniently handled using removable type optical disk. In the present paper, the trend and current issue of development for optical disk media are introduced. Standardization of next generation optical disk media, technology of recording and reading, and applications of magneto-optical devices are also discussed. Finally, a methodology of process optimization for design and fabrication of high density optical disk substrate is proposed.

• Journal of the Optical Society of Korea
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• 제14권3호
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• pp.266-276
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• 2010

In the present study, an optical system is proposed for maskless lithography using a digital micromirror device (DMD). The system consists of an illumination optical system, a DMD, and a projection lens system. The illumination optical system, developed for 95% uniformity, is composed of fly's eye lens plates, a 405 nm narrow band pass filter (NBPF), condensing lenses, a field lens and a 250W halogen lamp. The projection lens system, composed of 8 optical elements, is developed for 4 ${\mu}m$ resolution. The proposed system plays a role of an optical engine for PCB and/or FPD maskless lithography. Furthermore, many problems arising from the presence of masks in a conventional lithography system, such as expense and time in fabricating the masks, contamination by masks, disposal of masks, and the alignment of masks, may be solved by the proposed system. The proposed system is verified by lithography experiments which produce a line pattern with the resolution of 4 ${\mu}m$ line width.

• Current Optics and Photonics
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• 제7권2호
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• pp.166-175
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• 2023

We theoretically analyze and experimentally demonstrate a polarization-diversified four-channel optical demultiplexer (DeMUX) comprising a hybrid mode conversion-type polarization splitter rotator (PSR) and delayed Mach-Zehnder interferometer optical DeMUX for use in coarse wavelength division multiplexing (CWDM)-based optical interconnect applications. The Si wire-based device fabricated by a complementary metal-oxide semiconductor-compatible process exhibited nearly the same filter spectral response irrespective of the input polarization state under the PSR. The device had an extremely low insertion loss of <1.0 dB, polarization-dependent loss of <1.0 dB, and interchannel imbalance of <0.5 dB, suppressing unwanted wavelength and polarization crosstalk from neighboring channels of <-20 dB at each peak transmission channel grid.

• 광학세계
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• 제10권3호통권55호
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• pp.50-57
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• 1998

• 한국광학회:학술대회논문집
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• 한국광학회 2009년도 창립 20주년기념 특별학술발표회
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• pp.22-23
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• 2009

• 마이크로전자및패키징학회지
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• 제8권1호
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• pp.1-4
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• 2001

새로운 구조의 APF optical link용 Si pin photodetector를 제작하고 그 특성을 분석하였다. 제작된 소자는 금속-반도체 접촉주위에 $p^{+}$-guard ring구조와 광이 입사되는 수광면에 그물망 모양의 얕은 $p^{+}$-확산영역을 갖는다. 제작된 소자의 전기.광학적 특성을 -5 V의 동작전압에서 측정한 결과, 접합 커패시턴스와 암전류는 각각 4 pF와 180 pA로 나타났으며 광신호 전류와 감도특성는 670 nm이 중심파장을 갖는 2.2 $\mu$W의 입사광 전력 아래에서 각각 1.22 $\mu$A와 0.55 A/W로 나타났다. 제작된 소자는 650~700 nm의 파장영역에서 최대 spectral response를 보이고 있으며 낮은 점한 커패시턴스와 우수한 신호분리능력으로 인해 red light optics응용에서 광신호 검출에 적합하게 사용될 수 있을 것으로 기대된다.

• 한국결정성장학회지
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• 제23권5호
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• pp.224-229
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• 2013

Vanadium oxide thin films were deposited on $c-Al_2O_3$ (001) substrate by in-situ RF magnetron sputtering. Oxygen partial pressure was adjusted to prepare thermochromic $VO_2$ phase. X-ray diffraction patterns and scanning electron microscopy convincingly showed that plate-like $V_2O_5$ grains were changed into round-shape $VO_2$ grains as oxygen partial pressure decreased. After the optimized deposition conditions were fixed, the effect of substrate temperature and orientation on the optical properties of $VO_2$ thin films was analyzed.

• 한국전기전자재료학회논문지
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• 제21권2호
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• pp.173-177
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• 2008

We have developed the transparent passivation layer for top emission organic light emitting diodes using CsCl thin film by the thermal evaporation method. The CsCl film was deposited on the Ca/Ag semitransparent cathode. The optical transmittance of Ca/ Ag/CsCl triple layer is higher than that of Ca/Ag double layer in the visible range. The device with a structure of glass/Ni/2-TNATA/a-NPD/Alq3:C545T/BCP/Alq3/Ca/Ag/CsCl results in higher efficiency than the device without CsCl passivation layer. The device without CsCl thin film shows a current efficiency of 7 cd/A, whereas the device passivated with CsCl layer shows an efficiency of 10 cd/A. This increase of efficiency isresulted from the increased optical extraction by the CsCl passivation layer.

• 전기학회논문지
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• 제57권10호
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• pp.1829-1834
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• 2008

An optical switch/modulator is designed and the light propagating characteristics is analyzed by the simplified BPM. The distinctive feature of the switch/modulator is that all the waveguide branches are designed to be single-mode. Principle of the device is based on the coupled mode theory in the Y-junction interconnecting waveguide. In spite of all the waveguides are designed to be single-mode, adjusting the interconnecting waveguide length of the device, the same characteristics as existing device up to date is obtainable. Numerical results show that the switching characteristics periodically depends on the interconnecting waveguide length with a spatial of about 150${\mu}m$ in the Ti:LiNbO3 step index waveguide. The concept of design would be utilized effectively in fabricating the monolithic high density of optical integrated circuit.