• Journal of information and communication convergence engineering
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• v.5 no.4
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• pp.377-381
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• 2007

Nonlinear effects and chromatic dispersion are the main causes of pulse degradation in high bit-rate WDM transmission systems and several architectures have been proposed to compensate them by means of optical phase conjugation. In this paper, a new method to exploit an optical phase conjugator (OPC) for nonlinearity and dispersion cancellation is disclosed. The proposed method is using optimal total dispersion of each fiber sections and it is simpler than those previously described in literature. Power penalty between WDM channels and the maximum launch power in $28{\times}40$ Gbps WDM transmission system designed by optimal total dispersion are more decreased and more increased than those in the conventional WDM transmission system with OPC, respectively. Furthermore, optimal total dispersion proposed in this research should provide the flexible design of WDM system, which less depends on OPC position.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1433-1441
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• 2011

Design rules of optical transmission links with dispersion management (DM) and optical phase conjugation (OPC) for compensating optical signal distortion due to chromatic dispersion and self phase modulation (SPM) of single mode fiber (SMF) are investigated in this paper. Design rules consist of optimal net residual dispersion (NRD) and optimal range of launching power of wavelength division multiplexed (WDM) channels as a function of total transmission length and span length. In all considered total transmission length and span length, optimal NRD are obtained to +10 ps/nm and -10 ps/mn for transmission links, which is controlled by precompensation and postcompensation, respectively. It is confirmed that system performances are more improved and effective NRD for wide launching power have wider range as total transmission length and span length are more decreased.

• Journal of Advanced Navigation Technology
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• v.16 no.3
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• pp.440-448
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• 2012

Optimal net residual dispersion (NRD) and effective launching power range of optical transmission links with optical phase conjugator (OPC) and dispersion management (DM) for compensating the distorted wavelength division multiplexing (WDM) signals due to interaction of group velocity dispersion (GVD) and optical nonlinear effects. WDM systems considered in this research have optical links with the random distribution of residual dispersion per span (RDPS) in each single mode fiber (SMF) spans of only one half transmission section for designing the adaptive optical transmission system configurations. It is confirmed that optimal NRD is 10 ps/nm and effective launching power range is obtained to be -8~1 dBm under NRD = 10 ps/nm in optical links with total dispersion controlled by precompensation. And, it is also confirmed that optimal NRD is -10 ps/nm and effective launching power range is obtained to be -7.5~1 dBm under NRD = -10 ps/nm in optical links with total dispersion controlled by postcompensation.

• 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.

• Journal of Advanced Navigation Technology
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• v.14 no.5
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• pp.668-676
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• 2010

Optimal net residual dispersions (NRDs) of inline dispersion management (DM) for compensating the signal distortion of $24{\times}40$ Gbps WDM channels in optical transmission links, in which optical phase conjugator (OPC) is placed from 250 km to 750 km by spacing 50 km in 1,000 km total transmission length of single mode fiber (SMF), are induced as a function of various ope positions. And, performance improvement of WDM channels in transmission links with the induced optimal NRD is investigated by comparing with that in transmission links with NRD = 0 ps/nm. It is confirmed that optimal NRDs are decided by displacement of OPC from mid-way of total transmission length, i.e. 500 km, and the determinating and applying of optimal NRD in case of ope displacement into transmitters is more stable and effective than that in case of ope displacement into receivers from 500 km. Also, it is shown that eye opening penalties (EOPs) of WDM channels in transmission links with optimal NRD are improved by 1.5 dB to 3 dB, which are related with OPC position, from that obtained in transmission links with fixed NRD of 0 ps/nm.

• Journal of electromagnetic engineering and science
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• v.4 no.4
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• pp.162-167
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• 2004

In this paper, optimal position of optical phase conjugator(OPC) for best compensating distorted WDM channels due to both chromatic dispersion and self phase modulation(SPM) is numerically investigated, and the compensation characteristics of overall WDM channels at this position is investigated, comparing with that in case of OPC placed at mid-way of total transmission length. It is confirmed that the compensation extents in WDM system with OPC is more improved by the shifting OPC position from the mid-way of total transmission length. And, we confirmed that the optimal position of OPC must be selected to the position decreasing not only eye opening penalty(EOP) of overall WDM channels but also EOP deviation between WDM channels, and this OPC position should be altered as various system parameters such as modulation format, and fiber dispersion, etc. Using proposed configuration, it is possible to remove all in-line dispersion compensator, reducing span losses and system costs.

• Journal of information and communication convergence engineering
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• v.5 no.1
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• pp.17-22
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• 2007

In this paper, the optimal value of optical phase conjugator (OPC) position and the optimal values of dispersion coefficients of fiber sections for the best compensation of the distorted WDM signals with frequency chirp of -1 are induced to alternate with the symmetrical distributions of power and local dispersion with respect to OPC, which is difficult to form in real optical link due to fiber attenuation in mid-span spectral inversion (MSSI) technique. It is confirmed that the Q-factors of total channels of -18.5 dBm launching light power exceed 16.9 dB, which value corresponds to 10-12 BER, by applying the induced optimal parameter values into 16 channels ${\times}$ 40 Gbps WDM system, on the other hand the Q-factors of only 9 channels exceed that value in WDM system with the conventional MSSI technique. Thus, it is expected to expand the availability of OPC in WDM system through the using of the optimal parameter values that are induced by the proposed method in this paper, without the symmetrical distributions of power and local dispersion.

• Journal of electromagnetic engineering and science
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• v.5 no.1
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• pp.36-42
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• 2005

In this paper, the optimal position of optical phase conjugator(OPC) excellently compensating distorted WDM channels with initial frequency chirp due to both chromatic dispersion and self phase modulation(SPM) is numerically investigated. Highly-nonlinear dispersion shifted fiber(HNL-DSF) is used as a nonlinear medium of OPC in order to widely compensate WDM signal band. It is confirmed that if the OPC position was shifted from mid-way of total transmission length dependence on the initial frequency chirp as well as modulation format and fiber dispersion coefficient, it is possible to cancel the performance degradation owing to the initial frequency chirp. Using proposed configuration, it is possible to remove all in-line dispersion compensator, reducing span losses and system costs in the long-haul broadband WDM systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.594-597
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• 2012

Optimal link configuration in optical link with concentrated residual dispersion per span (RDPS) in only one fiber span and 0 ps/nm of RDPS in other fiber spans of each half transmission section with respect to optical phase conjugator (OPC) placed at middle of total transmission length is induced in this paper.

• 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.