• Title, Summary, Keyword: Highly Nonlinear Dispersion Shifted Fiber (HNL-DSF)

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Wideband Optical Phase Conjugator using HNL-DSF in WDM Systems with Path-Averaged Intensity Approximation Mid-Span Spectral Inversion (경로 평균 강도 근사 기법의 MSSI를 채택한 WDM 시스템에서 HNL-DSF를 갖는 광대역 광 위상 공액기)

  • Lee, Seong-Real;Lee, Yun-Hyun
    • Journal of Advanced Navigation Technology
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    • v.7 no.1
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    • pp.14-21
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    • 2003
  • We investigated the optimum pump light power compensating distorted WDM signal due to both chromatic dispersion and self phase modulation (SPM). The considered system is $3{\times}40$ 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 of optical phase conjugator (OPC) in the mid-way of total transmission line. We confirmed that HNL-DSF is an useful nonlinear medium in OPC for wideband WDM transmission, and the excellent compensation is obtained when the pump light power of HNL-DSF OPC was selected to equalize the conjugated light power into the second half fiber section with the input WDM signal light power depending on total transmission length. By this approach, it is verified the possibility to realize a long-haul high capacities WDM system by using PAIA MSSI compensation method, which have HNL-DSF OPC with optimal pump light power depending on transmission length.

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Pump Light Power of Wideband Optical Phase Conjugator using HNL-DSF in WDM Systems with MSSI (MSSI 기법을 채택한 WDM 시스템에서 HNL-DSF를 이용한 광대역 광 위상 공액기의 펌프 광 전력)

  • Lee Seong real;Cho Sung eun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.3A
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    • pp.168-177
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    • 2005
  • In this paper, we numerically investigated the optimum pump light power resulting best compensation of pulse distortion due to both chromatic dispersion and self phase modulation (SPM) in long-haul 3×40 Gbps wavelength division multiplexing (WDM) systems. We used mid-span spectral inversion (MSSI) method with path-averaged intensity approximation (PAIA) as compensation approach, which have 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 HNL-DSF is an useful nonlinear medium in OPC for wideband WDM transmission, and in order to achieve the excellent compensation the pump light power is selected to equal the conjugated light power into the latter half fiber section with the input light power of WDM channel depending on total transmission length. Also we confirmed that compensation degree of WDM channel with small conversion efficiency is improved by using pump light power increasing power conversion ratio upper than 1.

Calculation of Pump Light Power in Wideband Optical Phase Conjugator with Highly-Nonlinear Dispersion Shifted fiber (HNL-DSF를 이용한 광대역 광 위상 공액기의 펌프 광 전력 계산)

  • 이성렬;이하철
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.5A
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    • pp.473-483
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    • 2004
  • In this paper, we numerically investigated the optimum pump light power best compensating for pulse distortion due to both chromatic dispersion and self phase modulation (SPM) as a function of channel input power in 8 channel ${\times}$ 40 Gbps wavelength division multiplexing (WDM systems. Also we investigated the allowable maximum channel input power dependence on modulation format and fiber dispersion coefficient in the various pump light power of OPC. The considered WDM transmission system is based on path-averaged intensity approximation (PAIA) mid-span spectral inversion (MSSI) compensation method, which has highly-nonlinear dispersion shifted fiber (HNL-SDF) as nonlinear medium of optical phase conjugator (OPC) in the mid-way of total transmission line. We confirmed that optimal pump light power of HNL-DSF OPC depend on modulation format, initial channel input power, total transmission length and fiber dispersion. But optimal pump light power of HNL-DSF OPC must be selected to make power conversion ratio to almost unity. And we confirmed that, if we allow a 1 dB eye opening penalty (EOP), the tolerable maximum channel input power is increased by using RZ than NRZ as modulation format when pump light power of HNL-DSF OPC is not optimal value but another values.

Characteristics of Compensation for WDM Transmission with Equally Spaced Channels using Mid-Span Spectral Inversion (채널 간격이 일정한 WDM 전송에서의 Mid-Span Spectral Inversion을 이용한 보상 특성)

  • 이성렬;임황빈
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.6
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    • pp.619-626
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    • 2004
  • In this paper, we investigated the compensation characteristics of distorted 16-channel WDM signal due to chromatic dispersion self phase modulation(SPM) and four-wave mixing(FWM). The bit rate and uniform frequency spacing of WDM channels are assumed to be 40 Gbps and 100 ㎓, respectively. The compensation method used in this approach is mid- span spectral inversion(MSSI), Highly-nonlinear dispersion shifted fiber(HNL-DSF) is used as a nonlinear medium of optical phase conjugator(On) in order to widely compensate WDM signal band. We confirmed that applying MSSI in WDM channels within special input power level compensates overall interferenced channels mainly due to FWM. But for long wavelength WDM channels having lower conjugated light power with respect to signal light power, compensation quality is deteriorated as dispersion coefficient of fiber becomes higher. Consequently, we confirmed that it is effective D apply MSSI with HNL-DSF as a nonlinear medium of OPC to WDM transmission link with relative small dispersion in order to compensate equally spaced WDM channels.

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.

Characteristics of Compensation for Distorted WDM Channel with Inter-channel Interference due to Four-Wave Mixing (4-광파 혼합에 의한 채널 간섭이 존재하는 왜곡된 WDM 채널의 보상 특성)

  • 이성렬;손성찬;방효창;김지웅;조경룡
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.6
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    • pp.1234-1242
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    • 2004
  • In this paper, the characteristics of compensation for interferenced mid-channel signal by neighbor channels through four-wave mixing (FWM) process dominantly is investigated as a function of channel input power, fiber dispersion coefficient and transmission length in WDM system with equally spaced channels. The compensation method used in this research is mid-span spectral inversion(MSSI). The highly nonlinear dispersion shifted fiber (HNL-DSF) is used as a nonlinear medium of optical phase conjugator (OPC) in order to compensate wideband WDM signals. First, we confirmed that the effect of FWM on channel interference is gradually reduced as fiber dispersion coefficient becomes gradually smaller, independent of signal format. And, we confirmed that RZ is better than NRZ as a modulation format for transmitting high power channel with allowable reception quality. But realization of flexible WDM systems regardless of channel number variation is possible by using NRZ rather than RZ format.

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.

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.

Compensation for Distorted Signals by using Optimal Pump Light Power in WDM Systems with Non-midway Optical Phase Conjugator

  • Lee Seong-Real
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.7A
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    • pp.542-549
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    • 2005
  • In this paper, the optimal pump light power of optical phase conjugator (OPC) and the compensation characteristics of distorted WDM channel signals are numerically investigated, when the OPC with highly-nonlinear dispersion shifted fiber (HNL-DSF) not be placed at the mid-way of total transmission length. The total dispersion of former half section and latter half section is assumed to be same each other in this approach. It is confirmed that, in WDM transmission systems with OPC deviated from the mid-way, the pump light power for best compensation must be flexible selected depending on the OPC position. This optimal pump light power is gradually increased as the OPC is gradually closer to the receiver. Consequently, it is possible to establish the compensation system independent on the OPC position by setting optimal pump light power connected with the OPC position.

Compensation of Distorted WDM signals due to Cross Phase Modulation Effects using Mid-Span Spectral Inversion (상호 위상 변조에 의해 왜곡된 WDM 신호의 Mid-Span Spectral Inversion을 이용한 보상)

  • Lee, Seong-Real
    • Journal of Advanced Navigation Technology
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    • v.7 no.2
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    • pp.128-134
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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) as a function of transmission length using mid-span spectral inversion (MSSI) compensation method. The considered system is $3{\times}40$ Gbps intensity modulation direct detection (IM/DD) WDM transmission system. This system has highly nonlinear dispersion shifted fiber (HNL-DSF) as a nonlinear medium in optical phase conjugator (OPC). We confirmed that the transmission length is more increased by applying MSSI to distorted signal due to chromatic dispersion, SPM and XPM as dispersion coefficient of fiber becomes higher. And the compensation degree of distorted WDM channels due to chromatic dispersion, SPM and XPM becomes better stable as dispersion coefficient of fiber becomes higher.

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