• Title/Summary/Keyword: Optical Coherent

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Terabit-Per-Second Optical Super-Channel Receiver Models for Partial Demultiplexing of an OFDM Spectrum

  • Reza, Ahmed Galib;Rhee, June-Koo Kevin
    • Journal of the Optical Society of Korea
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    • v.19 no.4
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    • pp.334-339
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    • 2015

  • Terabit-per-second (Tb/s) transmission capacity for the next generation of long-haul communication networks can be achieved using multicarrier optical super-channel technology. In an elastic orthogonal frequency division multiplexing (OFDM) super-channel transmission system, demultiplexing a portion of an entire spectrum in the form of a subband with minimum power is critically required. A major obstacle to achieving this goal is the analog-to-digital converter (ADC), which is power-hungry and extremely expensive. Without a proper ADC that can work with low power, it is unrealistic to design a 100G coherent receiver suitable for a commercially deployable optical network. Discrete Fourier transform (DFT) is often seen as a primary technique for understanding partial demultiplexing, which can be attained either optically or electronically. If fairly comparable performance can be achieved with an all-optical DFT circuit, then a solution independent of data rate and modulation format can be obtained. In this paper, we investigate two distinct OFDM super-channel receiver models, based on electronic and all-optical DFT-technologies, for partial carrier demultiplexing in a multi-Tb/s transmission system. The performance comparison of the receivers is discussed in terms of bit-error-rate (BER) performance.

  • https://doi.org/10.3807/JOSK.2015.19.4.334 인용 PDF KSCI KPUBS HTML

Optical Components for High Speed Optical Communications (대용량 광통신 부품 기술 동향)

  • Baek, Yongsoon
    • Korean Journal of Optics and Photonics
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    • v.24 no.6
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    • pp.297-310
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    • 2013

  • With the explosive growth of internet data traffic due to the FTTH penetration, prevalence of smart devices and cloud network service, the demand for higher bandwidth is ever increasing with the pace of more than 40% annual growth. To accommodate ultra high bandwidth traffic, optical components in each hierarchy have progressed rapidly. WDM has begun to be deployed along with higher bandwidth service in the access network. Next-generation ROADM is under development for efficient network management in the metro network. For long-haul transmission, an advanced modulation scheme based on coherent transmission technology has been adopted to enhance spectral efficiency. In this paper, core components to meet the demands of high speed, high efficiency and low power consumption will be reviewed.

  • https://doi.org/10.3807/KJOP.2013.24.6.297 인용 PDF KSCI

Reduction of multiple-access interference in coherent optical CDMA systems based on all-optical differential detection (전 광학적인 차동 검출 방법을 이용한 코히런트 시간 광 CDMA 시스템에서의 다중접근 간섭 제거)

  • 김선종;김태영;박철수;박창수
    • Korean Journal of Optics and Photonics
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    • v.15 no.3
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    • pp.229-233
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    • 2004

  • We propose a novel scheme to suppress the multiple-access interference(MAI) in coherent optical CDMA systems. This is based on a differential detection using the dual-control NOLM. For an experimental demonstration, two encoded channels we constructed and decoded. These decoded signals are sent to the dual-control NOLM and a high autocorrelation peak with suppressed MAI at the output of the NOLM is observed. Signal-to-interference ratio is improved by 7 ㏈.

  • https://doi.org/10.3807/KJOP.2004.15.3.229 인용 PDF KSCI

Picosecond optical parametric generation and amplification using BBO crystals (BBO 결정을 이용한 Pico초 광매개 발생과 증폭)

  • 유난이;최혜영;차명식
    • Proceedings of the Optical Society of Korea Conference
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    • 2000.08a
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    • pp.244-245
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    • 2000

  • 비선형광학 결정을 이용한 optical parametric generation(OPG)은 coherent tunable radiation을 얻는 방법으로 매우 효과적이다. Beta barium borate(BBO) 결정은 비선형성이 클 뿐만 아니라 광손상문턱이 높고 자외선에서부터 근 적외선영역까지(2 -0.2$mu extrm{m}$) 투명하여 optical parametric oscillation(OPO)이나 OPG/OPA(optical parametric generation/amplification)에 많이 활용되고 있다.[1-2] 분광학적 연구와 여러 가지 응용 측면에서 넓은 영역의 파장가변이 손쉽고 높은 에너지를 갖는 pico 초coherent source는 중요하며, 이는 결정의 비선형성을 이용하여 공진기를 구성하지 않고서도 OPG/OPA를 통하여 실현 가능하다. (중략)

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