• 한국광학회지
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• 제12권4호
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• pp.327-333
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• 2001

위상반전(phase reversal)시키는 전극구조를 갖는 진행파 광변조기에서 주파수응답의 추정을 간결한 형태로 제시하였다. 유도된 식을 근거로 한 모의전산을 통하여 위상반전 전극구조가 대역통과 특성을 가질 수 있음을 보였고 진행파전극의 마이크로파(MW) 파라미터를 변화시켰을 때 주파수응답에 미치는 영향을 분석하였다. 특히 MW 유효굴절률과 변조영역의 길이를 변화시킴으로써 대역통과 특성을 가지는 주파수 응답의 중심주파수와 대역폭을 효과적으로 조절할 수 있음을 보였다.

• 한국광학회:학술대회논문집
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• 한국광학회 2008년도 동계학술발표회 논문집
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• pp.291-292
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• 2008

We fabricated 40Gbps electroabsorption modulator-integrated DFB lasers (EMLs). Adopting traveling-wave (TW) electrode and tilted facet improved high-frequency characteristics of EMLs. The 3dB bandwidth of E/O response for TW-EML was as large as 34 GHz, as compared with 27 GHz for lumped EML. Tilted facet formed by dry etching processes successfully reduced the optical feedback and the resonance in E/O response decreased to as small as 2.8 dB.

• 조명전기설비학회논문지
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• 제22권3호
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• pp.1-7
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• 2008

We have theoretically investigated the asymmetry effects on 10[Gb/s] optical duobinary transmitters from the viewpoint of the driving voltage ratios by computer simulations. For driving voltage ratios(=driving voltage/switching voltage) with smaller than 100[%], the transmission performance has been greatly affected by the asymmetry of the bandwidth of LPFs than that of the Mach-Zehnder Modulator driving voltage. On the other hand, for driving voltage ratios with 100[%], the transmission performance has been degraded by the asymmetry of the driving voltage and is not sensitive to that of the bandwidth of LPFs. For the transmission performance within 1[dB] power penalty under the asymmetry condition, the driving voltage ratio with 100[%] has performed better than the low driving voltage ratios.

• 대한전자공학회논문지
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• 제26권12호
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• pp.2016-2024
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• 1989

A versatile incoherent optical processing system is developed and analyzed in detail, in which an acousto-optic modulator is used to generate the temporal offset frequency for heterodyning and an optical scanner to process the input object in scanning mode. The operational characteristics of the systems are studied with respect to spatial filtering in terms of the spectral width change of the light source, the temporal offset frequency, and a scanning rate. To enhance the system's capability, two schemes for tuning the system's OTF, structural tuning and defocused object tuning, are also developed and verified with the MTF measurements and computer calculations.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 하계학술발표회
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• pp.192-193
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• 2000

공간 광변조기(spatial light modulator)는 빛의 진폭, 위상 혹은 편광 상태를 공간적으로 변조하는 소자이다. 2차원적인 화소 배열을 갖는 공간 광 변조기는, 전자 소자들이 지니지 않는, 정보를 고속으로 병렬 처리할 수 있는 기능에 힘입어, 광상관기, 광컴퓨터, 프로젝션 TV, 빔 프로젝트, 홀로그래피 메모리의 핵심 소자로 지난 50년간 활발히 연구되어, 액정 공간 광 변조기, 자기 광학 공간 광 변조기$^{(1)(2)}$ 등이 개발되었다. 이 중에서 자기광학 공간 괌 변조기는 화소의 스위칭 스피드가 빠르고, 견고하고, 내방사능성을 가질 뿐만 아니라, 비휘발성이라는 장점을 가지고 있어, 주로 우주항공용의 Miniature Ruggedized Optical Correlator(MROC)$^{(3)}$ 에 사용되어 왔다. 본 논문에서는 새로운 개념의 공간 광 변조기인 자성 포토닉 결정을 이용한 자기 광학 공간 광 변조기(MPC-MOSLM)의 제조에 관하여 논하고자 한다 (중략)

• Journal of the Optical Society of Korea
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• 제16권4호
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• pp.443-448
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• 2012

A polarimetric experimental method was developed to determine the Jones matrix elements of transparent optical materials without sign ambiguity. A set of polarization dependent transmittance data of the samples was measured with polarizer - sample - analyzer system and another set of data was measured with polarizer - sample - quarter-wave plate - analyzer. Two data sets were compared and mathematically analyzed to obtain the correct signs of the elements of the matrix. The Jones matrix elements of a quarter-wave plate were determined to check the validity of the method. The experimentally obtained matrix elements of the quarter-wave plate were consistent with the theoretical expectations. The same method was applied to obtain the Jones matrix elements of a twisted nematic liquid crystal panel.

• 전자공학회논문지D
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• 제35D권8호
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• pp.53-61
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• 1998

Dynamic characteristics of widely tunable SGDBR/SSGDBR laser diodes integrated with an electroabsorption modulator is inestigated using an improved large-signal timef-domain model. First, wide tunning properties of a SGDBR laser diode and a SSGDBR laser diode are analyzed respectively and compared with each other. And, intensity-modulation characteristics of a SGDBR laser diode incorprating an electroabsorption modulator are investigated. It is shown that an external modulation has the lower frequency chirp by 1/20 for almost same extinction ratios than a direct modulation, and a nearly transform-limited pulse train can be generated using the optical gating of an electroabsorption modulator.

• 한국통신학회논문지
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• 제25권1B호
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• pp.42-47
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• 2000

버스트 모드 패킷 트래픽 조건에서 스위칭 소광비를 최대화하는 전기 광학 광변조기의 바이어스 안정화를 위한 새로운 방법을 입증하였다. 광변조기의 오프 레벨 출력 전력을 샘플링하고 최소화함으로써 패킷 트래픽 밀도의 변화에 무관하게 높은 소광비를 갖는 광 게이트로서 동작한다

• Current Optics and Photonics
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• 제5권3호
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• pp.261-269
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• 2021

Binary-phase complex spatial light modulators (BP-C-SLMs) are proposed and simulated. This study shows that bottom-top mirror-symmetrical uniaxial systems between two orthogonal polarizers allow one to construct BP-C-SLMs. BP-C-SLMs double the information-handling capacity per pixel, compared to the conventional amplitude-only spatial light modulators (A-SLMs), as well as being simply implemented with a single spatial light modulator (SLM), rather than a combination of an A-SLM and a binary-phase SLMs. Under limited conditions, BP-C-SLMs can control only the amplitude in single-phase space, and act as A-SLMs.

• Journal of information and communication convergence engineering
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• 제6권2호
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• pp.192-197
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• 2008

High-speed harmonic optical modulation-demodulation schemes are presented and a possibility of the schemes for applying to high-speed light wave transmission system is tested at microwave frequency range. An example of this concept is as follows : Light wave is modulated succeedingly through cascaded optical modulators by a sub-carrier to produce a modulated light wave at harmonic frequency which is higher than the feasible frequency of the individual modulators. For demodulation of the base-band signal, the high frequency optical sub-carrier is down-converted by the same kind of optical modulator with the same concept of harmonic modulation.