• Title/Summary/Keyword: Gratings

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Performance of Bipolar Optical Spectral Encoding CDMA with Modified PN Codes

  • Chang, Sun-Hyok;Kim, Bong-Kyu;Park, Heuk;Lee, Won-Kyoung;Kim, Kwang-Joon
    • ETRI Journal
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    • v.28 no.4
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    • pp.513-516
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    • 2006
  • Experimental demonstration of bipolar spectral encoding code-division multiple-access with modified pseudorandom noise codes is presented. Bipolar spectral encoding is achieved with an erbium-doped fiber amplifier amplified spontaneous emission source and arrayed waveguide gratings. The bit-error rate performance of 1.25 Gbps signal transmission over 80 km single mode fiber is measured in a multiple-user environment.

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Transmission Mode of HPDLC Based on Rubbery Polymers

  • Kim, Eun-Hee;Woo, Ju-Yeon;Kim, Byung-Kyu
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.520-523
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    • 2003
  • We used three types of reactive diluents with different chemical structures, N-vinyl-pyrrollidone(NVP), ethyl hexyl acrylate(EHA) and hydroxyehtyl methacrylate(HEMA). It was founded that N-vinylpyrrollidone(NVP) and ethyl hexyl acrylate(EHA) based PUA with low molecular weight polypropylene glycol(PPG) at low oligomer content give high diffraction efficiency. The morphology of the resultant gratings was analyzed by using scanning electron microscopy(SEM) and Tg of the polymer matrix by dynamic mechanical thermal analysis(DMTA).

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Wavelength selective long-period fiber gratings (장주기 광섬유격자의 파장가변 특성)

  • Ham, Joung-Woo;Lee, Jong-Hun;Lee, Kyung-Shik
    • Proceedings of the KIEE Conference
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    • 2001.07c
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    • pp.1826-1828
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    • 2001
  • 본 논문에서는 주기적으로 홈을 새긴 V자 홈과 평판 사이에 광섬유를 놓고 압력을 인가함으로써 유도되는 파장가변 가능한 장주기 광섬유격자의 제작 및 특성에 대해서 살펴 보았다. 이러한 방식으로 제작된 장주기 광섬유격자의 투과특성 및 모드결합 특성은 기존의 장주기 광섬유격자와 유사한 특성을 보이면서도 모드결합이 일어나는 중심파장을 거의 180nm 이상으로 가변할 수 있었다.

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Intensity Dependence of Mutually Pumped Phase Conjugator in Photorefractive Crystal (광굴절결정에서 인코히어런트한 두 빔에 의해 발생되는 위상공액파의 광세기 의존성)

  • 박서연;곽종훈;김천민
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.29A no.2
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    • pp.41-46
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    • 1992
  • Mutually pumped phase conjugator(MPPC) is experimentally investigated and analyzed in terms of fanning gratings of a photorefractive BaTiO$_3$ crystal. As considering the intensity-dependent absorption and coupling cofficients in photorefractive two wave mixing, the dependence of phase conjugate reflectivites on the incident angle, beam ratio, and total intensity in MPPC is analyzed.

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Dielectric Waveguide Channel Dropping Filter (유전체 도파관을 이용한 채널 드로핑 필터)

  • 김신기;박동철;오승엽
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.1
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    • pp.1-7
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    • 1988
  • A new type broadband channel dropping filter which has a potential use as a millimeter-wave multiplexer has been realized by properly connecting 3-dB directional couplers and bandstop filters. 90\ulcorner3-dB directional couplers have been designed using two nonuniformly coupled dielectric image guides, while bandstop filters with Chebyshev passbands have been designed using dielectric image-guide grating structure. Effective dielectric constant method has been aplied to the image-guide dispersion analysis and to the design of bandstop gratings and 3-dB couplers. Experimental results in excellent agreement with computed responses are demonstrated.

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Optical pulse compression at 1.319$\mu\textrm{m}$ through fiber-grating pair and further compression using soliton effects (광섬유와 회절격자를 이용한 1.319$\mu\textrm{m}$파장 광펄스의 압축과 솔리톤 효과에 의한 재압축)

  • 이재승
    • Proceedings of the Optical Society of Korea Conference
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    • 1991.06a
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    • pp.102-108
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    • 1991
  • Utilizing self-phase modulation effects of a dispersion-shifted fiber and delay-line characteristics of two gratings, mode-locked 80 ps pulses at 1.319${\mu}{\textrm}{m}$ wavelength from a Nd: YAG laser are compressed down to 2.1 ps. These pulses are further compressed down to 340 fs using higher order soliton effects in a common single mode fiber.

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Simulation of Moire Effect in 3D Displays

  • Saveljev, Vladimir;Kim, Sung-Kyu
    • Journal of the Optical Society of Korea
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    • v.14 no.4
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    • pp.310-315
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    • 2010
  • Theoretical and experimental investigations of moires in 3D displays were performed. To describe and minimize moires, we propose the polar representation form of moire waves. The experimental and theoretical data are in good agreement except in the neighborhood of the minimization angle. The implicit formulas are found for visible moires of line gratings at finite distances. The computer simulation and the physical experiments confirm the moire appearance for this case.

Gain-Coupled Distributed-Feedback Effects in GaAs/AlGaAs Quantum-Wire Arrays

  • Kim, Tae-Geun;Y. Tsuji;Mutsuo Ogura
    • Journal of the Korean Vacuum Society
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    • v.12 no.S1
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    • pp.52-55
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    • 2003
  • GaAs/AlGaAs quantum-wire (QWR) gain-coupled distributed-feedback (GC-DFB) lasers are fabricated and characterized Constant metalorganic chemical vapor deposition (MOCVD) growth is used to avoid grating overgrowth during the fabrication of DFB structures. Numerical calculation shows large gain anisotropy by optical feedback along the DFB directions near Bragg wavelength. DFB lasing via QWR active gratings is also experimentally achieved.

Three-beam Apodization in Photopolymer

  • Do Due Dung;Kim Nam;Lee Kwon Yeon;Jeon Seok Hee
    • Journal of the Optical Society of Korea
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    • v.9 no.2
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    • pp.59-63
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    • 2005
  • In this paper, we present a novel apodization technique using three beams to fabricate an apodized grating in photopolymer. An orthogonal-polarization beam used to control the saturated modulation amplitude of the grating is added during recording time. As a result of the experiment, holographic apodized gratings with uniform, inverse Gaussian, and triangular profiles are fabricated successfully in DuPont's HRF-150-38 photopolymer.