• Title/Summary/Keyword: optical characteristic

검색결과 814건 처리시간 0.027초

장파장 응용을 위한 InP/InGaAs HBT의 광특성 (Characteristic of InP/InGaAs HBT for Long Wavelength Application)

  • 김강대;허영헌;박재홍;김용규;문태정;황성범;송정근
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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    • pp.1073-1076
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    • 2003
  • This paper shows the performance as a photodetector of InP/InGaAs HPT operated with a base bias and forntside optical injection through the emitter. InP/InGaAs HPT produced the high optical gain of about 16.2 where HPT is biased at Vc=1V, I$_{B}$=20$\mu$A with an input optical power of 2.4$\mu$W. And we examined that the optical gain of HPTs becomes larger when operating in 3-terminal configuration rather than 2-terminal with the floating base. The optical performance of InP/InGaAs HPT is an attractive to the PIN Photodetector for use in long wavelength optical receivers.s.

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Bimorph PZT를 이용한 고밀도 광학헤드의 정밀위치 및 간극제어 (Precision Position and Gap Control for High Density Optical Head Using Bimorph PZT)

  • 권영기;홍어진;박태욱;박노철;양현석;박영필
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2004년도 춘계학술대회논문집
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    • pp.888-893
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    • 2004
  • This paper proposed a dual actuator using bimorph PZT for information storage device based on prove array NSOM(Near-field Scanning Optical Microscopy). The gap between the media and the optical head should be maintained within the optical tolerance. Therefore, a new actuator having high sensitivity is required. Bimorph PZT, which has fast access time and high sensitivity characteristic, is suitable for this precise actuating system. This paper is focused on derivation of mathematical model of dual bimorph PZT actuator and control algorithm. Hamilton's principle was used for mathematical model. The model is verified by FEA(Finite Element Analysis), and compared with experimental results. Different control algorithms were used f3r two bimorph PZT actuating same direction and opposite direction. The gap between recording media and optical head was controlled within 20nm in experiment.

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비구면렌즈 설계를 위한 칼코게나이드 Ge-Sb-Se 광학계 및 결정화 특성 연구 (Chalcogenide Ge-Sb-Se Optical and Crystallization Characteristics for Basic a Planning Aspheric Lens)

  • 명태식;고준빈
    • 한국재료학회지
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    • 제26권11호
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    • pp.598-603
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    • 2016
  • The recent development of electro-optic devices and anticorrosion media has led to the necessity to investigate infrared optical systems with solid-solid interfaces of materials that often have the characteristic of amorphousness. One of the most promising classes of materials for those purposes seems to be the chalcogenide glasses. Chalcogenide glasses, based on the Ge-Sb-Se system, have drawn a great deal of attention because of their use in preparing optical lenses and transparent fibers in the range of 3~12 um. In this study, amorphous Ge-Sb-Se chalcogenide for application in an infrared optical product design and manufacture was prepared by a standard melt-quenching technique. The results of the structural, optical and surface roughness analysis of high purity Ge-Sb-Se chalcogenide glasses are reported after various annealing processes.

1.25Gbps PON용 버스트 모드 광 수신기 (A Burst-mode Optical Receiver for 1.25Gbps PON)

  • 기현철
    • 한국인터넷방송통신학회논문지
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    • 제13권5호
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    • pp.49-54
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    • 2013
  • 1.25Gbps PON(Passive Optical Network)용 버스트 모드 광 수신기를 설계하고 $0.8{\mu}m$ BiCMOS공정을 사용해 제작하였다. 지수함수 증폭기를 이용하여 AGC(Automatic Gain Control) 신호 생성 소요 시간을 단축시켜 버스트 앞부분의 데이터 손실을 최소화하였다. 측정결과 버스트 모드 광 수신기의 AGC 기능은 정상적으로 잘 동작하고 특성도 양호함을 확인하였다. 한편, 아이패턴의 아이는 열려있기는 하나 심한 파형 왜곡이 있고, 이로 인해 지터 특성 저하되고 있었다.

전방위카메라를 이용한 이동로봇에서의 이동물체 인식 (Recognition of Moving Objects in Mobile Robot with an Omnidirectional Camera)

  • 김종철;김영명
    • 로봇학회논문지
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    • 제3권2호
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    • pp.91-98
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    • 2008
  • This paper describes the recognition method of moving objects in mobile robot with an omnidirectional camera. The moving object is detected using the specific pattern of an optical flow in omnidirectional image. This paper consists of two parts. In the first part, the pattern of an optical flow is investigated in omnidirectional image. The optical flow in omnidirectional image is influenced on the geometry characteristic of an omnidirectional camera. The pattern of an optical flow is theoretically and experimentally investigated. In the second part, the detection of moving objects is presented from the estimated optical flow. The moving object is extracted through the relative evaluation of optical flows which is derived from the pattern of optical flow. In particular, Focus-Of-Expansion (FOE) and Focus-Of-Contraction (FOC) vectors are defined from the estimated optical flow. They are used as reference vectors for the relative evaluation of optical flows. The proposed algorithm is performed in four motions of a mobile robot such as straight forward, left turn, right turn and rotation. Experimental results using real movie show the effectiveness of the proposed method.

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광학적으로 제어된 섬유를 가진 비균일 불안정성의 과도 응답의 특성 (Characteristic of Transient Response in Nonuniform Instability with Optically Controlled Fiber)

  • 판린한;박광채
    • 한국정보전자통신기술학회논문지
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    • 제9권5호
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    • pp.445-450
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    • 2016
  • In this paper we study the effect of chaos in nonuniform instability with optical fiber based IoT networks. The transient response of optically controlled fiber has also described. Nonlinear optical fiber effects especially fiber scattering in networks has emerged as the essential means active optical devices. The paradigm instability in fiber Internet serves as a test for fundamental study of chaos and its suppression and exploitation in practical application in optical communication. This paper attempts to present a survey and some of our research findings on the nature of chaotic effect on Internet based optical communication. The transient response in optical fiber has been evaluated theoretically by calculating the variation of the scattering function. The lines has used under open ended termination containing optically induced region. The scattered optical waves in a fiber used in optic communications are temporally unstable above certain threshold intensity.

광섬유 격자 센서와 회전 광학 커플러를 사용한 회전하는 블레이드 여러 지점에서의 온라인 변형률 측정 (Online Strain Measurement at Multiple Points on a Rotating Blade with Fiber Bragg Grating Sensors and a Rotary Optical Coupler)

  • 이종민;황요하
    • 대한기계학회논문집A
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    • 제32권1호
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    • pp.77-82
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    • 2008
  • Strain-gauges have been dominantly used to measure strain at various points on a rotor, however, either a slip ring or telemetry has to be used to send sensor signals to data acquisition instruments at stationary side. Both slip ring and telemetry have numerous inherent problems which force severe limitations in real applications. This paper introduces a new rotor condition monitoring system using FBG(Fiber Bragg Grating) sensors and a rotary optical coupler. A single optical fiber with many FBG sensors is installed on the rotor and an optical dynamic interrogator is installed at stationary side. The sensor signal connection between rotating part and stationary part is made by the rotary optical coupling method which makes use of light's unique characteristic-light travels through space. Broad band light source from the interrogator travels to the optical fiber on the rotor and reflected FBG sensor signals travel back to the optical fiber on stationary side and are connected to the interrogator. Rotary optical coupler's insertion loss change due to rotation is compensated by using a reference sensor installed at the center of the rotor. The proposed system's performance has been successfully demonstrated by accurately measuring strains at 5 points on a blade rotating at high speed.

Study of Optical Transmission Performance in IP-over-WDM Networks Based on FSK/ASK Combined Modulation Format

  • Xiangjun, Xin;Andre, Paulo Sergio de Brito;Teixeira, Antonio Luis Jesus;Monteiro, Paulo P.;Rocha, Jose R. F. da
    • ETRI Journal
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    • 제27권3호
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    • pp.267-272
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    • 2005
  • The transmission performance of optical labeling based on a combined frequency shift keying/amplitude shift keying (FSK/ASK) format is studied by numerical simulation. The simulation demonstrates that the bit-error ratio (BER) characteristic of an ASK signal is limited by the extinction ratio, received optical power, and dispersion, simultaneously. However, an FSK signal is mainly limited by the extinction ratio (ER) and received optical power when the peak spectrum, which is used to detect the FSK signal, is relatively narrow.

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Electro-optic Electric Field Sensor Utilizing Ti:LiNbO3 Symmetric Mach-Zehnder Interferometers

  • Jung, Hong-Sik
    • Journal of the Optical Society of Korea
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    • 제16권1호
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    • pp.47-52
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    • 2012
  • The use of a $Ti:LiNbO_3$ symmetric Mach-Zehnder interferometric intensity modulator with a push-pull lumped electrode and a plate-type probe antenna to measure an electric field strength is described. The modulator has a small device size of $46{\times}7{\times}1mm$ and operates at a wavelength of $1.3{\mu}m$. The output characteristic of the interferometer shows the modulation depth of 100% and 75%, and $V_{\pi}$ voltage of 6.6 V, and 6.6 V at the 200 Hz and 1 KHz, respectively. The minimum detectable electric field is ~1.84 V/m, ~3.28 V/m, and ~11.6 V/m, corresponding to a dynamic range of about ~22 dB, ~17 dB, and ~6 dB at frequencies of 500 KHz, 1 MHz and 5 MHz, respectively.

다채널 광정렬 장치 로터리 스테이지 개발에 관한 연구 (A Study on the Development of the Rotary Stage for Multi-Channel Optical Alignment System)

  • 정상화;차경래
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2003년도 추계학술대회
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    • pp.143-148
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    • 2003
  • In recent years, as the optical Communication systems are developed, the demands of essential parts such as splitter, coupler, WDM, and AWG filter are grow rapidly. The fabrication process for them is not, however, automatic. On that reason, the automation is needed for the grow of productivity. The optical alignment and attach ment is the core process in fabrication. In this paper, the 6-axis rotary stage for multi-channel optical alignment system is developed and the dynamic characteristic of this system is studied.

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