• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.784-786
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• 2010

Implementation possibility of inline dispersion management (DM) using bi-end schemes, which consist of one single mode fiber (SMF) and two dispersion compensating fiber (DCF) placed at front and rear of SMF, respectively, is investigated for compensating total dispersion accumulated in a span of WDM transmission links. It is confirmed that if net residual dispersion (NRD) is decided to be ${\pm}10\;ps/nm$ then bi-end scheme is effective to compensate for WDM channels with wide launching power range.

• 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.

• 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.

• Journal of Advanced Navigation Technology
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• v.13 no.5
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• pp.656-661
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• 2009

High-quality transmission of $24{\times}40$ Gbps WDM signals obtained through controling residual dispersion per span (RDPS) in optical transmission links with zero net residual dispersion (NRD) of inline dispersion management (DM) of optical transmission links is researched. It is confirmed that RDPS values, which is improving system performance, depends on launch power of WDM channels, but optimal RDPS, which can simultaneously improve WDM signals with relative wide launch power ranges, becomes to be 210~230 ps/nm. Also, it is shown that effective launch power range that making eye opening penalty (EOP) of worst channel to below 1 dB is more increased as RDPS is more increased.

• Journal of Advanced Navigation Technology
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• v.12 no.4
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• pp.311-316
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• 2008

A configuration scheme of optical link effectively compensating chromatic dispersion and nonlinear effects accumulated in optical link with single mode fibers (SMFs) is proposed. The proposed optical link configuration consist of optical phase conjugator (OPC) placed at middle of total transmission length and inline dispersion management (DM) as a role of compensating cumulated in each optical repeater of SMF by dispersion compensating fiber (DCF). Net residual dispersion (NRD) of this optical link is designed to be controlled through precompensation and postcompensating. The precompensation and postcompensation are designed to be determined by DCF after transmitter and before receiver, respectively. It is confirmed that optical link configuration with symmetric dispersion map with respect to OPC, which is implemented by controlling NRD through both precompensation and postcompensation, is better to be effective and adaptive than other configuration with NRD controlled by only precompensation or postcompensation.

• 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 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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.780-783
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• 2010

Net residual dispersion (NRD) available to transmit RZ formats with different 24 wavelength as a function of duty cycles of RZ format and residual dispersion per span (RDPS) is induced by controlling precompensation only in 960 km optical transmission links of single mode fiber (SMF) with inline dispersion management (DM) for compensating of accumulated dispersion. It is confirmed that effective NRD range for different 24 wavelengths is gradually broadening as RDPS is more smaller, and as duty cycle of RZ format is more larger in the same RDPS.

• Journal of Advanced Navigation Technology
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• v.14 no.6
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• pp.831-837
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• 2010

Optimal conditions of 40 Gbps RZ format for implementation of optical time division multiplexing/wavelength division multiplexing (OTDM/WDM) transmission system are induced by analyzing and comparing performance depending on duty cycle and extinction ratio (ER). Optical phase conjugator (OPC) and inline dispersion management (DM) are applied into optical transmission links for compensating signal distortion due to chromatic dispersion and nonlinearity of fiber. It is confirmed that RZ format of 0.25 duty cycle is less effected by system performance change depending on ER and it is suitable for multiplexing to 160 Gbps signal through OTDM. Also, it is shown that performance improvement of RZ format determined by same net residual dispersion (NRD) is more increased as residual dispersion per span (RDPS) becomes large.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.8A
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• pp.801-809
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• 2010

Limitation of optical phase conjugation for implementation of wideband and long-haul WDM transmission system is symmetric distribution of optical power and local dispersion with respect to optical phase conjugator (OPC). This limitation forces OPC to place at midway of total transmission length. This paper shows that the limitation of optical phase conjugation is overcame by applying optimal net residual dispersion (NRD) into transmission links based in inline dispersion management (DM). Optimal NRD related with OPC position is decided by combination of precompensation and postcompensation. It is confirmed that optimal NRD depends on launch power of WDM channels and system performance criterion as well as OPC position. That is, in case of 1 dB eye opening penaty (EOP) as a performance criterion for WDM channels with 0 dBm launch power, it is confirmed that OPC is allowed to place at anywhere of 1000 km by applying best NRD related with exact OPC position into transmission links. And, it is confirmed that, under 3 dB EOP criterioin for WDM channels with 3 dBm launch power, OPC is allowed to place at 350~700 km by applying NRD between 100 ps/nm and 200 ps/nm into transmission links, though that NRD value is not best combination of precompensation and postcompensation.