• Journal of Advanced Navigation Technology
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• v.20 no.5
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• pp.462-467
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• 2016

Dispersion management (DM) combining with mid-spans spectral inversion (MSSI) is one of the various techniques compensating for the distorted optical signals. For the flexible implementation of this configured link, the compensation characteristics in the optical link with artificial distribution of the gradually ascending and descending of single mode fiber (SMF)'s lengths and residual dispersion per span (RDPS) as the number of fiber spans are assessed as a function of the control positions of net residual dispersion (NRD). It is confirmed that the best compensation is obtained by distributing gradually ascending or descending of SMF's lengths and RDPS capable to place NRD control position at fiber span, in which optical pulse width is most narrow.

• Journal of Advanced Navigation Technology
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• v.17 no.4
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• pp.413-420
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• 2013

The design rule depending on total transmission length is induced in the optical links with residual dispersion per span (RDPS) of the random distribution, which is adopted for implementing the flexible systems of wavelength division multiplexing (WDM) transmission with dispersion management (DM) and optical phase conjugation. DM parameters used for the analysis of the design rule are the effective net residual dispersion (NRD) and the effective launch power. It is confirmed that the flexible optical network configuration with the total transmission length lower than 1,000 km is possible, because the system performance difference between the randomly distribution and the uniform distribution of RDPS is small. And, in the optical links with the randomly distributed RDPS, the wide NRD can be applied for transmitting WDM channels of the relatively wide launch power.

• 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.

• Journal of Advanced Navigation Technology
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• v.19 no.2
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• pp.147-152
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• 2015

The compensation characteristics of WDM channels depending on residual dispersion per spans (RDPS) deviation in optical links with the randomly distributed RDPS for the adaptive configuration are investigated in this paper. Also, the link design rule related with RDPS deviations is proposed, from the viewpoint of the allowable net residual dispersion (NRD). It is confirmed that the effect of compensation for the distorted WDM channels is more increased as RDPS deviation is smaller. Also, it is confirmed that the decrease of the allowable NRD range for the exact eye opening penalty (EOP) is proportional to RDPS deviation. Therefore, the results of this research is expected to be the design reference for the flexible link configuration of long-haul optical transmission links.

• Journal of information and communication convergence engineering
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• v.14 no.2
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• pp.71-77
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• 2016

The combination of dispersion management (DM) and midway optical phase conjugation (OPC) is one of the promising techniques for compensating for optical signal distortion due to group velocity dispersion and nonlinear fiber effects. However, in this combination technique, midway OPC restricts the flexible optical link configuration. Therefore, the possibility of implementing the flexible optical link configuration with non-midway OPC applied to complete inline DM links is investigated in this study. It is confirmed that although the compensation using non-midway OPC for the distorted WDM channels is less effective than that using midway OPC, when non-midway OPC is placed at positions closer to the transmitters, the deployment of precompensation (i.e., the sequence of DCF + SMF)-OPC-postcompensation (i.e., the sequence of SMF + DCF) is more advantageous for the compensation. On the other hand, inverse deployment with respect to OPC (i.e., postcompensation-OPC-precompensation) is more advantageous when non-midway OPC is placed at positions closer to the receivers.

• Current Optics and Photonics
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• v.7 no.4
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• pp.443-448
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• 2023

The ±1-order Kelly sidebands with dispersion-dependent spacing of mode-locking fiber lasers are investigated for frequency-tunable terahertz signal generation. The principle of dispersion dependence of Kelly sidebands is analyzed. A new method, which is a dispersion-management mechanism introduced into the fiber-laser cavity, is proposed to generate Kelly sidebands with widely tunable wavelength spacing. A spacing tuning range of up to 28.46 nm of the ±1-order Kelly sidebands is obtained in simulation. Using the data of the optical spectrum with dispersion-dependent Kelly sidebands, the frequency spectrum of generated terahertz signals is calculated. Consequently, the signal frequency can be changed from 0.09 to 2.27 THz.

• Journal of information and communication convergence engineering
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• v.17 no.4
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• pp.227-233
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• 2019

In long-haul optical communication system consisting of standard single-mode fiber spans and fiber amplifiers, such as the erbium-doped fiber amplifier, performance is deteriorated by signal distortion due to chromatic dispersion and nonlinearity of the fiber. A combination of dispersion management and optical phase conjugation is an effective technique to compensate for the distortion. In an optical link configured by this combination, a dispersion map mainly affects the compensation of the distorted optical signals. This paper proposes new dispersion maps configured by the decaying or expanding distribution of residual dispersion per span (RDPS) in a dispersion-managed link combined with a midway optical phase conjugator. The effect of the proposed dispersion maps on the compensation for distorted 24 channel × 40 Gbps wavelength-division multiplexed signals was assessed through numerical simulation. It was confirmed that all the proposed dispersion maps are most appropriate for the compensation and, furthermore, for the flexibility of link configuration than conventional links.

• Journal of Advanced Navigation Technology
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• v.19 no.4
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• pp.323-329
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• 2015

The compensation characteristics of the distorted WDM channels compensated for by dispersion management (DM) and optical phase conjugation in the long-haul ($50\;fiber\;spans{\times}80km$) transmission link with the randomly distributed single mode fiber (SMF) length and residual dispersion per spans (RDPS) for implementing of the flexible link configuration are investigated. It is confirmed that the compensation effect in the link with the randomly distributed SMF length and RDPS is similar with that in the link with the uniform distribution, when the launch power of WDM channels are restricted within 0 dBm. This result means that the proposed link configuration is useful for designing and deploying the long-haul WDM transmission link.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.749-751
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• 2009

Optical link design technique for compensating of distorted 40 Gbps ${\times}$ 24 channels WDM signals is researched. The considered optical link consists of optical phase conjugator (OPC) placed at 100 km and 900 km, which are non-midway of total transmission distance, and dispersion management (DM). It is confirmed that optimal net residual dispersions (NRD) are 800 ps/nm and 900 ps/nm when OPC placed at 100 km and 900 km, respectively.

• Journal of Advanced Navigation Technology
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• v.22 no.5
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• pp.462-466
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• 2018

Optical phase conjugation combining with dispersion management (DM) is promising technique to compensate for signal distortion due to chromatic dispersion and nonlinear Kerr effects of single mode fiber (SMF) in optical communication systems. However the fixed SMF length in every fiber spans usually used in the optical links with optical phase conjugator(OPC) and DM restricts the flexible link configuration. The goal of this paper is to investigate the possibility of the flexible configurations of the ultra-high and long-haul optical transmission systems by using the random distribution of SMF length of each fiber spans consisted of the optical link. It is confirmed that the excellent compensation for the distorted wavelength division multiplexing signals in the optical links with the randomly distribution is obtained in case of the shorter averaged SMF length over all fiber spans. It is also confirmed that the control method of net residual dispersion suitable to good compensation is postcompensation and the extent of net residual dispersion(NRD) is -10 ps/nm in DM optical link consisted of fiber spans with the randomly distributed SMF lengths.