• Title/Summary/Keyword: WDM 전송 시스템

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Increase of Transmission Distance in 1 Tbps WDM Transmission System (1 Tbps WDM 전송 시스템의 전송 거리 신장)

  • Lee, Seong-Real
    • Journal of Advanced Navigation Technology
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    • v.13 no.4
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    • pp.559-565
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    • 2009
  • The implementation possibility and increasement of transmission distance of 1 Tbps WDM transmission systems through the applying optical link configuration with inline dispersion management (DM) and optical phase conjugator (OPC) is investigated. When the considered optical link configuration is applied into $26{\times}40$ Gbps WDM transmission system and the optimal net residual dispersions (NRDs) depending on transmission length are decided, the effective transmission distanceis highly increased than that resulted in same system with fixed 0 ps/nm NRD in all transmission length. And, design rule of inline DM optical link is also shown through inducing the effective range of precompensation and postcompensation depending on transmission distance and launching power of WDM channel.

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Transmission Distance Depending on Transmission Capacityin Inline Dispersion Managed WDM Systems (Inline 분산 제어가 적용된 WDM 시스템에서 전송 용량에 따른 전송 거리)

  • Lee, Seong-Real;Cho, Sung-Eon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.5
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    • pp.959-966
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    • 2009
  • Effective transmission distance depending on transmission capacity of WDM systems with inline dispersion management (DM) and optical phase conjugator (OPC) at middle of total transmission length is investigated. The range of net residual dispersion (NRD) resulting 1 dB eye opening penalty (EOP) in 1 Tbps WDM system, in which NRD controlled by only postcompensation, is also investigated. It is confirmed that effective transmission distances are increasedto longer than several hundreds kilometers by applying optimal NRD depending on transmission capacity and distance. And it is confirmed that in 1 Tbps WDM system if NRD is determined to +17 ps/nm, the maximum transmission distance is achieved, and, especially, in long-haul 1 Tbps WDM system the effective NRD range will be determined within positive value.

Cross Phase Modulation Effects on 120 Gbps WDM Transmission Systems with Mid-Span Spectral Inversion for Compensation of Distorted Optical Pulse (광 펄스 왜곡의 보상을 위해 Mid-Span Spectral Inversion 기법을 채택한 120 Gbps WDM 시스템에서 채널간 상호 위상 변조 현상의 영향)

  • 이성렬;권순녀;이윤현
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.7
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    • pp.741-749
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    • 2003
  • In this paper, we investigated the degree of compensation for WDM channel signal distortion due to chromatic dispersion, self phase modulation(SPM) and cross phase modulation(XPM). The considered system is 120 Gbps (3${\times}$40 Gbps) intensity modulation direct detection(IM/DD) WDM transmission system with path-averaged intensity approximation(PAIA) mid-span spectral inversion(MSSI) as compensation method. This system have highly nonlinear dispersion shifted fiber(HNL-DSF) as nonlinear medium in optical phase conjugator(OPC). We use 1 dB eye opening peralty(EOP) in order to evaluate the characteristics of compensation for distorted WDM channels. We confirmed that improvement of transmission distance and performance is achieved by MSSI method to distorted long-haul IM/DD WDM channels due to chromatic dispersion, SPM and XPM. And in the aspect of compensation for distorted pulse due to XPM, the MSSI method is effective to IM/DD WDM transmission system with high fiber dispersion coefficient.

Implemeention and performance measurement of a novel in-service supervisory system for WDM transmission link (파장분할다중화방식 전송로의 In-service 감시를 위한 새로운 감시시스템의 구현 및 성능평가)

  • 김필한;윤호성;박남규;서재은;정기태;유기원;이규행
    • Korean Journal of Optics and Photonics
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    • v.12 no.2
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    • pp.129-134
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    • 2001
  • Novel supervisory system for WDM transmission link using conventional optical time domain reflectometry was presented. By modifying the structure of erbuim doped fiber amplifier to support bi-directional transmission at arDR pulse wavelength and launching the optical pulse into transmission link in the opposite direction of data signal propagation to avoid the distortion by cross-gain modulation, it is possible to monitor the WDM link in service. To prove the validity of proposed scheme, the supervision result of 2.5 Gbps $\times$ 8 channel WDM 320 km transmission system in service by arDR was presented. And power penalty due to monitoring was measured as smaller than 0.3 dB. .3 dB.

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System Performance Improvements in WDM ($24{\times}40$ Gbps) Transmission using Optical Phase Conjugator and Dispersion Management (WDM ($24{\times}40$ Gbps) 전송에서 광 위상 공액기와 분산 제어를 이용한 시스템 성능 개선)

  • Lee, Seong-Real;Yim, Hwang-Bin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.10B
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    • pp.855-864
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    • 2008
  • Optical link techniques compensating chromatic dispersion and nonlinear effects, which affect distortion of optical signals, generated in single mode fiber are investigated through computer simulation and design rule of these link techniques is proposed for implementation of wideband and long-haul WDM ($24{\times}40$ Gbps) transmission system. The optical link consist of dispersion management (DM) compensating the cumulated dispersion through total transmission line and optical phase conjugation in middle of total transmission line for compensating distorted signals by frequency inversion. DM schemes considered in this research are lumped DM and inline DM. It is confirmed that eye opening penalty (EOP) of overall WDM channels are more improved than those in WDM transmission systems with only optical phase conjugator (OPC), if DM is additionally applied to these systems. And, design rule in both DM schemes are proposed by using effective residual dispersion range. It is confirmed that inline DM is better than lumped DM in the improving EOP of total WDM channels and in effective residual dispersion range.

Interchannel RF Power Fluctuation in WDM-RoF System Employing Photonic Crystal Fiber (광결정 광섬유를 이용한 WDM-RoF 시스템의 채널간 전력변화 편차 분석)

  • Kim, So-Eun;Lee, Chung-Ghiu
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.4
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    • pp.821-828
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    • 2012
  • In this paper, we report that the differences between RF power levels can be improved in wavelength division multiplexing - radio over fiber (WDM-RoF) system by using a photonic crystal fiber. In a WDM-RoF system, each WDM channel experiences different received RF power level fluctuation in remote node (RN) because of wavelength-dependent dispersion. Since each WDM channel experiences different power fluctuation, the RF power fluctuation acts as a design constraint in viewpoint of network design. We designed a photonic crystal fiber to improve the effect of wavelength- dependent dispersion on RF power fluctuation. Also, we analyzed the wavelength-dependent difference of inter-channel RF power fluctuations.

Effect of Cross Phase Modulation on Channel Compensation in 320 Gbps Intensity Modulation / Direct Detection WDM Transmission Systems (320 Gbps 강도 변조 직접 검파 WDM 시스템의 채널 보상에서 상호 위상 변조의 영향)

  • 이성렬;김지웅;손성찬
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.5
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    • pp.1134-1140
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    • 2004
  • In this paper, we investigated the effect of cross phase modulation(XPM) on compensation for WDM channel distortion due to chromatic dispersion, self phase modulation and XPM as a function of fiber dispersion coefficient and modulation format in 320 Gbps WDM systems. The considered WDM transmission system is based on mid-span spectral inversion(MSSI) compensation method, which has highly nonlinear dispersion shifted fiber(HNL-DSF) as nonlinear medium of optical phase conjugator (OPC) in the mid-way of total transmission line. We confirmed that the maximum channel input power resulting 1 dB eye opening penalty is reduced due to XPM effect on channel distortion, even if MSSI method was applied to WDM system. But, we confirmed that the effect of XPM on channel distortion becomes decrease as fiber dispersion coefficient of WDM system becomes larger. Futhermore, we confirmed that NRZ is better than RZ as a modulation format for similarly compensating overall WDM channels in WDM system with large fiber dispersion coefficient in order to minimize the effect of the XPM on channel distortion.

The Compensation Characteristics of WDM Channel Distortion Dependence on NRZ format and RZ Format (NRZ 형식과 RZ 형식에 따른 WDM채널 왜곡의 보상 특성)

  • 이성렬;조성언
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.11
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    • pp.1184-1190
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    • 2003
  • In this paper, we investigated the characteristics of compensation for distorted NRZ signal and RZ signal in 320 Gbps WDM system as a function of channel input power, fiber dispersion coefficient and transmission length, respectively. The considered WDM transmission system is based on mid-span spectral inversion(MSSI) compensation method having highly nonlinear dispersion shifted fiber(HNL-DSF) optical phase conjugator(OPC) in the mid-way of total transmission line. We confirmed that the signal input power range compensated by MSSI is broadened by using RZ as a signal format in WDM system with small fiber dispersion coefficient, The range of fiber dispersion coefficient compensating overall distorted WDM channels is limited, because degree of compensation for distorted channel with low conjugated-wave power becomes gradually degrade as fiber dispersion coefficient becomes gradually higher. It is showed that RZ format and NRZ format is suited for long-haul transmission in WDM system with small fiber dispersion coefficient and with large fiber dispersion coefficient, respectively.

The Design of Optical Transmitter for WDM Transmission System controlled by U-processor ($\mu$-processor로 제어되는 WDM 전송 시스템용 광 전송기 설계)

  • 염진수;이규정;허창우
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.7 no.4
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    • pp.699-704
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    • 2003
  • This paper has been studied about the design of optical transmitter with stable output wavelength in WDM transmission system. The stabilized constant current circuit is designed with deviation less than 10$\mu$A. The temperature control circuit is constructed for the control of internal temperature of laser diode. Also, the wavelength locker is used in optical output. Finally, A/D, D/A converter and micro-processor are used for the control of these.

Compensation Characteristics Dependence on Variation of Fiber Dispersion in WDM Systems with Optical Phase Conjugator (광 위상 공액기가 적용된 WDM 시스템에서 광섬유 분산 계수 변동에 따른 보상 특성)

  • 이성렬;박경호;정명래
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.5
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    • pp.517-524
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    • 2004
  • In this paper, we investigated the compensation characteristics of distorted NRZ format and RZ format signal dependence on dispersion variation of each transmission section in 8-channel WDM system. The WDM system have two transmission sections of unequal length with respect to optical phase conjugator(OPC) position. We select highly-nonlinear dispersion shifted fiber(HNL-DSF) as a nonlinear medium of OPC in order to convert wideband signal waves to conjugated waves. First, we confirmed that RZ is better than NRZ as a modulation format for maintenance or stable performance, when total dispersion or both sections in WDM system is different each other. Also, we confirmed that total dispersion of the short length section must be smaller than that of the long length section in order to excellently compensate for NRZ format signal.