• Title/Summary/Keyword: Wavelength Selective

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Computer Generated Hologram for Beam Control of LCOS based Wavelength Selective Switch (LCOS기반의 파장선택스위치 빔제어용 컴퓨터 생성 홀로그램)

  • Lee, Yong-Min;Han, Chang Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.6
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    • pp.744-749
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    • 2016
  • This paper presents the design of a computer-generated hologram for beam control of an LCOS-based wavelength selective switch, which is the core technology for next-generation ROADM. By introducing a computer-generated hologram instead of general grating patterns to control the LCOS device, we contribute to building a more efficient wavelength selective switch. With the use of phase modulation properties of LCOS devices, we designed the hologram for five-port output and a 40-channel wavelength selective switch. We applied a multi-level phase modulation technique with the Gerchberg-Saxton algorithm to produce the hologram, which is easily scalable to any different type of wavelength selective switch. With an experimental setup, we verified the usability of the hologram designed for five-port output. We also suggest a hologram design technique for beam control of a 40-channel wavelength selective switch.

Widely Tunable Wavelength-Selective Reflector Using Polymer Waveguide Double-Ring-Resonator Add/Drop Filter and Loop-back Mirror

  • Lee, Ho;Kim, Gun-Woo;Park, Jun-Oh;Kim, Su-Hyun;Chung, Young-Chul
    • Journal of the Optical Society of Korea
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    • v.12 no.3
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    • pp.157-161
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    • 2008
  • A wavelength-selective reflector, composed of a double-ring-resonator add/drop filter and a loop-back mirror at the drop port to be used for a hybrid-integrated tunable laser is designed and fabricated. High-index-contrast polymer waveguide is used to realize a compact device as small as $2mm{\times}0.4mm$. The radii of the rings are slightly different from each other to obtain a wide wavelength tuning via a vernier effect. Peak reflectivity is measured to be 52% for TE mode and polarization-dependent wavelength shift is 0.95 nm. The tuning range is measured to be about 42 nm for applied current as small as 46 mA.

A Study on a Compact Coupler between an Optical Fiber and a Grating-assisted Graphene-embedded Silicon Waveguide for a Wavelength-selective Photodetector

  • Heo, Hyungjun;Kim, Sangin
    • Current Optics and Photonics
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    • v.1 no.5
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    • pp.514-524
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    • 2017
  • We proposed an integrated wavelength-selective photodetector based on a grating-assisted contradirectional coupler and a graphene absorption layer for a coarse wavelength division multiplexing (CWDM) communication system. The center wavelength of the absorption spectrum of the proposed device can be tuned simply by changing the period of the grating, and the proposed device structure is suitable to forming a cascaded structure. Therefore, an array of the proposed device of different grating periods can be used for simultaneous wavelength demultiplexing and signal detection in a CWDM communication system. Our theoretical study showed that the designed device with a grating length of $500{\mu}m$ could have an absorption of 95.1%, an insertion loss of 0.2 dB, and a 3 dB bandwidth of 7.5 nm, resulting in a -14 dB crosstalk to adjacent CWDM channels. We believe that the proposed device array can provide a compact and economic solution to receiver implementation in the CWDM system by combining functions of wavelength demultiplexing and signal detection.

Polarization selective diffraction grating using birefringence of the liquid crystal polymer (액정폴리머의 복굴절 특성을 이용한 편광선택형 회절격자)

  • An, Jun-Won;Kim, Nam
    • Proceedings of the Optical Society of Korea Conference
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    • 2007.02a
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    • pp.163-164
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    • 2007
  • We have described a polarization selective diffraction grating using liquid crystal polymer and experimentally demonstrated. From the experimental results, intensity ratios of 1.171 for p-polarization and of 0.0072 for s-polarization are achieved by 650nm wavelength, respectively.

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Two Wavelength OLED with the Stacked GDI602(691)/GDI602(Rubrene) Fluorescent Layer (Stacked GDI602(691)/GDI602(Rubrene) 형광층을 갖는 2-파장 유기발광소자)

  • Jang, Ji-Geun;Chang, Ho-Jung;Oh, Myung-Hwan;Kang, Jung-Won;Lee, Jun-Young;Gong, Myoung-Seon;Lee, Young-Kwan;Kim, Hee-Won
    • Korean Journal of Materials Research
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    • v.17 no.4
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    • pp.198-202
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    • 2007
  • A new organic light emitting device(OLED) with two peak wavelength(blue and yellow) emission was fabricated using the selective doping in a single fluorescent host , and its electrical and optical characteristics were investigated. The fabricated device showed the luminance and efficiency of 1600 $Cd/m^2$ and 2.4 Im/W under the applied voltage of 10V, respectively. And its electroluminescent spectra had two peak wavelengths of 470nm and 560nm emitting bluish white light. The OLED with dual wavelength emission in this experiment is likely to be developed as a white OLED with simpler fluorescent system than conventional devices.

Radiation From a Current Filament Located inside a Cylindrical Frequency Selective Surface

  • Uzer, Ali;Ege, Tuncay
    • ETRI Journal
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    • v.26 no.5
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    • pp.481-485
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    • 2004
  • We consider electromagnetic field radiation properties of a current filament placed at the origin of a cylindrical frequency selective surface (CFSS). The CFSS consists of free standing metal strips with two-dimensional periodicity. The analysis is based on a cylindrical Floquet mode wave expansion technique. We observed that near the half wavelength resonance frequencies, there exist some specific frequencies at which the surface becomes totally transparent.

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Design analysis of high efficiency crystalline silicon solar cell using the selective emitter (선택적 에미터를 적용한 고효율 결정질 실리콘 태양전지 구조 설계)

  • Lim, Jong-Keun;Lee, Won-Jae;Moon, In-Sik;Oh, Hoon;Cho, Eun-Chel
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.355-358
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    • 2009
  • This paper presents the technology of selective emitter for high efficiency crystalline silicon solar cell. The effect of selective emitter is analyzed by using the simulation program for solar cell, PC1D. The selective emitter shows better spectral response in short wavelength regions compared to homogeneous emitter. Therefore, the efficiency of solar cell with selective emitter can be improved by changing the sheet resistance from 60 $\Omega/\square$ to 120 $\Omega/\square$. In addition, the power loss of solar cell can be minimized by optimizing width and gap of the finger electrodes on the selective emitter.

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Analysis of Coupled Mode Theory for Design of Coupler Between Optical Fiber And Grating Assisted Waveguide (광섬유와 격자구조 도파로 결합기 설계를 위한 결합 모드 이론 분석)

  • Heo, Hyung-Jun;Kim, Sang-In
    • The Journal of the Korea institute of electronic communication sciences
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    • v.12 no.4
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    • pp.561-568
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    • 2017
  • In order to effectively utilize the Coarse Wavelength Division Multiplexing(CWDM) technology in optical integrated devices, a design of a wavelength selective coupler structure between an optical fiber and an optical waveguide in a flat substrate is can be considered. In this paper, we consider the coupling between a silicon waveguide with an air trench and a single mode fiber. We investigated the tendency of coupling efficiency and its limitations according to the grating depth. For this purpose, the coupling efficiency of coupler structure designed through modeling based on coupled mode theory is predicted and quantitatively compared with simulation results using finite element method.

A Four-Channel Laser Array with Four 10 Gbps Monolithic EAMs Each Integrated with a DBR Laser

  • Sim, Jae-Sik;Kim, Sung-Bock;Kwon, Yong-Hwan;Baek, Yong-Soon;Ryu, Sang-Wan
    • ETRI Journal
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    • v.28 no.4
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    • pp.533-536
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    • 2006
  • A distributed Bragg reflector (DBR) laser and a high speed electroabsorption modulator (EAM) are integrated on the basis of the selective area growth technique. The typical threshold current is 4 to 6 mA, and the side mode suppression ratio is over 40 dB with single mode operation at 1550 nm. The DBR laser exhibits 2.5 to 3.3 mW fiber output power at a laser gain current of 100 mA, and a modulator bias voltage of 0 V. The 3 dB bandwidth is 13 GHz. A 10 Gbps non-return to zero operation with 12 dB extinction ratio is obtained. A four-channel laser array with 100 GHz wavelength spacing was fabricated and its operation at the designed wavelength was confirmed.

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