• Journal of the Optical Society of Korea
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• v.1 no.1
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• pp.41-43
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• 1997

We report the operation of a self-adaptive vector phase conjugate laser (VPCL) oscillator which compensates intracavity polarization distortion and wavefront aberration simultaneously. The VPCL in Nd:YAG gain media produce an output with energy of 125mJ in a 20ns single-longitudinal-mode pulse at 10Hz, which is unaffected by intracavity polarization distortion.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.310-311
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• 2003

비선형 Kerr 매질에서 광파의 전파 특성을 해석하기 위해 지금까지 다양한 수치해석 방법들이 연구되어오고 있다 그중 FDTD 방식은 시간의 종속적인 Maxwell curl 방정식에 대해 어떠한 시간적, 공간적 근사를 사용하지 않고 광파의 전파 특성을 시뮬레이션하기 위해 유도되었기 때문에 산란과 같은 종축방향 불연속 문제나 비종축 파의 전파 특성 문제에 대해 보다 신뢰성 있는 해석 결과를 얻을 수 있으며, 비선형 Kerr 매질에서의 광파의 전파 특성에 대해서 보다 정확한 해석이 가능하다고 알려져 있다. (중략)

• Proceedings of the Optical Society of Korea Conference
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• 1989.02a
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• pp.165-168
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• 1989

A finite-element method is developed to calculate the impedance of arbitrarily shaped electrodes on traveling-wave modulators. This method employs the divergence theorem to obtain the total charge on an electrode from the node potential values. By using this method, the impedance of multi strip-line electrodes on anisotropic inhomogeneous dielectric media was analysed and the effect of non-zero electrode thickness was calculated.

• Broadcasting and Media Magazine
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• v.16 no.2
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• pp.73-83
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• 2011

홀로그래픽 광학소자(HOE; holographic optical elements)는 높은 회절효율과 협대역 주파수 특성, 그리고 여러 가지 기능을 하나의 소자로 구현할 수 있다는 특성을 갖고 있어 비행기와 자동차의 정보 표시를 위한 HUD(head-up display), 증강현실용 HMD(head mounted display), 2D/3D 디스플레이용 스크린 등에 널리 활용되고 있다. 이에 홀로그래픽 광학소자(HOE)의 동작특성과 디스플레이에 활용되고 있는 몇 가지 예를 통해 그 활용가치와 앞으로 홀로그래픽 광학소자가 좀 더 보편화되기 위해 풀어야 할 당면과제 등에 대해 다루고자 한다.

• Proceedings of the Korea Database Society Conference
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• 1995.12a
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• pp.68-79
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• 1995

HiMEDIA 전략 LG의 강점인 H/W 사업분야의 세계일류화를 지향하고, 향후 유망분야인 S/W와 Service 신 사업 참여에 LG의 역량을 집중토록함. $\square$ Hardware 신 사업： ⇒LG의 강점인 Device분야의 신제품의 지속적 개발(DVD, DVCR, HDTV등) ⇒한국 및 해외 Alliance 강화를 통한 VOD 사업 역량 배가 ⇒SI(System Integration)사업에 대한 타당성 검토 ⇒주요 Component의 핵심기술 개발(TFT-LCD, Optical Pick-up등)(중략)

• Journal of the Optical Society of Korea
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• v.7 no.4
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• pp.211-215
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• 2003

Statistical characteristics of the backscattered light from turbid tissues obtained by polarizationsensitive optical coherence tomography are investigated. The amplitude of the backscattered light is found to faithfully follow the Rayleigh distribution predicted by the scattering theory of electromagnetic waves in random media. The probability density function of the phase difference between the two orthogonal polarization components of the backscattered light is explicitly derived and then verified in comparison with the experimental data measured from in-vitro tissues of porcine ligament.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.4
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• pp.793-796
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• 2010

The equalizer compensates a signal distorted by transmission lines and amplifying stages, so the signal can have uniform characteristics over all frequency range. The equalizer in ODD(Optical Disc Drive) improves the stability of the extracted clock from a received signal and the readability of an inserted disc by suppressing noise and ISI(Inter-Symbol Inference). The length of marks-spaces and track pitch on discs becomes shorter as the recording density of an optical media is higher, which causes noise and ISI. And, the sensitivity about the fluctuation of physical systems is higher as the optical devices become more complicate. This paper proposes a method to select the coefficient of built-in equalizer of ODD in order to maintain the quality of signals against noise and ISI caused by system fluctuation.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.663-665
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• 2004

Ethernet-based passive optical network(EPON) technology is being considered as a promising solution for next-generation broadband access network. It must have the property of high efficiency, low cost, and support quality of service(QoS). A major feature for this new architecture is the use of a shared transmission media between all connected optical network unit(ONU). Hence, medium access control(MAC) arbitration mechanisms are essential for the successful implementation of EPON. In this paper we propose a simple dynamic bandwidth allocation(DBA) algorithm that improves the performance of network and supports IP-based multimedia applications with the bursty data traffic. In addition, we introduce analytic models of proposed algorithms and prove the system based on our algorithm to be asymptotically stable. Simulation results show the new DBA algorithm provides high bandwidth efficiency and low queueing delay of ONU in EPON.

• Journal of Sensor Science and Technology
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• v.21 no.6
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• pp.429-433
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• 2012

In this paper, we reduced the optical noise interference in a visible light communication system using two color LEDs. In the transmitter, the original and the inverted signals of the transmitted data modulated a red LED and a blue LED, respectively. In the receiver, a differential detector which is composed of two photodetectors and an optical red filter detected the mixed signal radiated from the two LEDs. In an environment that the optical noise from a fluorescent lamp exists, the signal-to-noise ratio in this system was improved by about 20dB compared to that in the conventional system which uses a single LED and a single photodetector.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.580-584
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• 1997

As the optical disk drive is getting applied to wider ranges, higher density of media and higher velocity of spindle motor are demanded and therefore its design criterion is becoming more strict. Especially, the vibration problem is one of the most important factors to be considered for reliable performance. In this study, the possibility of the application of the vibration absorber using rubber mount was investigated by 3 dimensional modeling and analysis by Recurdyn program. The model chosen was a vibration absorber using rubber mount installed on the sled base of the optical disk drive.