• 제목/요약/키워드: optical transmitter

검색결과 212건 처리시간 0.036초

외부변조 방식의 광송신기 제작 2.5Gbit/s 신호의 150km 광섬유 전송 (Fabrication of an externally modulated optical transmitter and transmission of 2.5Gbit/s signal over a 150 km long nondispersion-shifted fiber))

  • 한정희;윤태열;이상수;이창희
    • 전자공학회논문지A
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    • 제32A권11호
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    • pp.86-93
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    • 1995
  • An optical transmitter was designed and implemented using a commercially available LiNbO$_{3}$ Mach-Zehnder modulator and the power amplifiers. We have adopted a new method to stabilize the bias voltage of the modulator using the second order harmonic component of the dithering signal. This technique has been applied successfully to the 2.5 Gbit/s external modulator for more than 6 hours without bit error rate degradaton. We demonstrated a repeaterless transmission of a 2.5 Gbit/s signal over 150 km nondispersion-shifted fiber using the transmitter. The receiver sensitivity was -34.5 dBm at 10$_{-10}$ bit error rate. No appreciable BER degradation due to fiber dispersion were observed after transmission.

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Passive Star 토플로지와 WDM을 사용한 다중채널 광섬유 LAN을 위한 Multiple Access 르로토콜 (Multiple Access Protocols for a Multichannel Optical Fibre Local Area Network Using a Passive Star Topology and WDM)

  • 이형우
    • 전자공학회논문지A
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    • 제32A권9호
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    • pp.1184-1201
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    • 1995
  • Two multiple access protocols are proposed for a multichannel WDM optical fibre local area network or metropolitan area network in which users are interconnected using a passive star topology. Each user has a single tunable transmitter and a single tunable receiver. A transmitter sends a control packet before its data packet transmission so that its intended receivers can tune to the proper data channel wavelength. The maximum throughput of the proposed protocols are independent of the effective normalized propagation delay which may include the transmitter and receiver tuning times and the processing delays. The maximum throughputs of the protocols are analyzed and compared with those of the existing ones by numerical examples. The message delay of the R- Aloha/synchronous N-server switch protocol which is suitable for the queued users is also analyzed.

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Optical Signals Using Superposition of Optical Receiver Modes

  • Lee, Jae Seung
    • Current Optics and Photonics
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    • 제1권4호
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    • pp.308-314
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    • 2017
  • A particular optical receiver has its own optical receiver modes (ORMs) determined by its optical and electrical filters. Superposing the ORM waveforms at the transmitter, we can generate a new type of optical signals, called ORM signals. After optical detection, they produce pre-specified voltage waveforms accurately, which is advantageous for digital signal processing. Assuming a Gaussian optical receiver, where the optical and electrical filters are Gaussian, we illustrate various phase-shift keying ORM signals using two ORMs by changing their relative phase. We also illustrate multi-level ORM signal patterns using two or more ORMs.

Microwave Photonics Frequency-Converted Link Using Electroabsorption Devices

  • Wu, Y.;Shin, D.S.;Chang, W.S.C.;Yu, P.K.L.
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제4권1호
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    • pp.74-81
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    • 2004
  • We propose a novel scheme to transmit high center frequency RF signals using electroabsorption devices (EADs) as frequency converters at the transmitter and the receiver. In this approach frequency heterodyning is employed for obtaining high center frequency. With the EAD as a detector/mixer at the receiver we demonstrated a smaller conversion loss than that of the conventional modulator/mixer. With EAD as a modulator/mixer at the transmitter and with two heterodyned lasers to generate an optical local oscillator (LO), we demonstrated a large reduction (${\sim}23dB$) in conversion loss, and the transmission is not limited by the optical saturation of the EAD. This transmission scheme has optical single-side-band transmission feature which greatly relieves the fiber dispersion effect.

원형 프레넬 집광형 POF 주광 조명시스템 성능 평가 연구 (Circular Fresnel POF(Plastic Optical Fiber) Daylighting System Performance Evaluation Study)

  • 강은철;최용전;윤광식;이의준
    • 한국태양에너지학회 논문집
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    • 제31권1호
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    • pp.31-36
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    • 2011
  • CF(Circular Fresnel) POF(Plastic Optical Fiber) daylighting system is a beam daylighting system utilizing solar direct beam radiation. In this study, a CF POF daylighting system has been introduced, developed and applied to KIER test buildings. The CF POF daylighting system consists of three parts: light collector, light transmitter and light diffuser. The light collector includes a Circular Fresnel lens focusing solar direct illuminance by sun tracking. The light transmitter contains the POF cable which has light transmission loss of 4.5% per meter. The light diffuser has about 80% diffuser efficiency. This study aims to evaluate of POF daylighting system performance. At the results of a CFPOF system performance evaluation, the theoretical CFPOF system efficiency was 41.9% and the actual CFPOF system efficiency at the KIER test building was 37.5%. The difference was due partly to the connecting efficiency.

초고속 광송수신 소자·부품 기술 (Ultrahigh-Speed Photonic Devices and Components Technologies for Optical Transceivers)

  • 김종회;한영탁;김덕준;김동철;최중선;이동훈;이서영
    • 전자통신동향분석
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    • 제34권5호
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    • pp.81-90
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    • 2019
  • The data rate for transmission through fiber-optic cables has increased to 400 Gbps in single-wavelength channels. However, speeds up to 1 Tbps are required now to meet the ever-increasing bandwidth demand driven by the diverse requirements of contemporary applications for high-quality on-demand video streaming, cloud services, various social media, and emerging 5G-enabled applications. Because the data rates of the per-channel optical interfaces depend strongly on the operational speed of the optoelectronic devices used in optical transceivers, ultrahigh-speed photonic devices and components, and eventually, chip-level transmitter and receiver technologies, are essentially required to realize futuristic optical transceivers with data rates of 1 Tbps and beyond. In this paper, we review the recent progress achieved in high-speed optoelectronic devices, such as laser diodes, optical modulators, photodiodes, and the transmitter-receiver optical subassembly for optical transceivers in data centers and in metro/long-haul transmission.

Compact Infrared/Visible Laser Transmitter Featuring an Extended Detectable Trajectory

  • Kim, Haeng-In;Lee, Hong-Shik;Lee, Sang-Shin
    • Journal of the Optical Society of Korea
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    • 제16권4호
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    • pp.331-335
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    • 2012
  • A miniaturized laser beam transmitter, in which a visible laser module at ${\lambda}$=650 nm is precisely stacked upon an infrared (IR) module at ${\lambda}$=905 nm, has been proposed and constructed to provide an IR collimated beam in conjunction with a collinear monitoring visible beam. In particular, the IR beam is selectively dispersed through a perforated sheet diffuser, so as to create a rapidly diverging close-range beam in addition to a highly defined long-range beam simultaneously. The complementary close-range beam plays a role in mitigating the blind region in the vicinity of the transmitter, which is inevitably missed by the main long-range beam, thereby uniformly extending the transmitter's effective trajectory that is sensed by a receiver. The proposed transmitter was designed through numerical simulations and then fabricated by incorporating a diffuser sheet, perforated with an aperture of 2 mm. For the manufactured transmitter, the IR long-range beam was observed to have divergences of ~2.3 and 1.6 mrad in the fast and slow axes, respectively, while the short-range beam yielded a divergence of ~24 mrad. The angular alignment between the long-range IR and visible beams was as accurate as ~0.5 mrad. According to an outdoor feasibility test involving a receiver, the combination of the IR long- and short-range beams was proven to achieve a nearly uniform trajectory over a distance ranging up to ~600 m, with an average detectable cross-section of ${\sim}60{\times}80cm^2$.

광 무선 이동통신용 2차원 추적 광학 수신계 설계 (Design of 2-dimensional trackling optical receiver systems for optical wireless mobile communications)

  • 박승현;이동석;김경헌;이일항
    • 한국광학회:학술대회논문집
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    • 한국광학회 2004년도 하계학술발표회
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    • pp.28-29
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    • 2004
  • Optical wireless mobile communications have the potential to provide wide bandwidth and security . We have proposed and designed the 2-dimensional tracking optical receiver systems for optical wireless mobile communication. The receiver system consist of 4${\times}$4 photodiode array can receive optical signal from the transmitter. The room size is 5${\times}$5m$^2$ and the room height is 3m.

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PON 기반 광가입자망에서 방송 신호 전송을 위한 단일 LD을 이용한 디지털/SCM 신호 동시 변조기술 (Simultaneous modulation of digital/SCM signal using a single LD for broadcasting in PON based optical access network)

  • 김태영;김경현;한상국
    • 대한전자공학회논문지TC
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    • 제43권5호
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    • pp.1-6
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    • 2006
  • PON기반 광가입자망에서 방송신호 전송을 위한 방법으로써 단일 LD를 이용한 디지털/SCM신호 동시 변조방식의 성능을 파장이 다른 두개의 LD에 디지털 및 SCM신호를 각각 변조한 방식과 비교하였다. 실험을 통해, 변조를 위해 인가되는 전류의 최소값이 LD의 threshold 전류의 약 1.5배 이상인 경우 디지털 및 SCM신호의 상호간섭이 최소화됨을 확인하였다. 또한 LD의 anode 단자와 cathode 단자에 각각 디지털 및 SCM신호를 인가함으로서 효율적으로 회로설계가 가능한 광송신기 구조를 제안하고 실험적으로 검증하였다.