• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.209-212
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• 2001

We Propose a novel structure add/drop multiplexer based on an all-fiber Mach-Zehnder interferometer and fiber Bragg grating. In this structure, wavelength separation is achieved by adjusting the amount of the phase shift in the Mach-Zehnder interferometer. The proposed add/drop multiplexer drops a part of signal at a specific wavelength and transmit the remnant of the signal to the different node separated wavelength in WDM network.

• IE interfaces
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• v.14 no.2
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• pp.148-157
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• 2001

This paper considers a network restoration algorithm for all-optical WDM networks. As the increasing traffic and transmission speed, any failure on the networks will lead to loss of huge data and disruption of the services. Therefore, a network restoration algorithm is necessary for the high-speed all-optical networks. This paper suggests a distributed restoration algorithm for line or channel level failures under the dynamic rerouting. For the algorithm, some measures for performance evaluation are explicitly derived and simulation studies are exploited to evaluate its usability by SLAM(Simulation Language for Alternative Modeling) II.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.6 s.324
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• pp.69-78
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• 2004

This paper proposes architecture and characteristics of a multi-ring based optical network with single-hop between edge nodes using the concept of circuit switching and multi-wavelength label switching to solve delay problem caused by applying crossconnectors as transit nodes in the wavelength division multiplexing(WDM) network. We suggest multi-ring based architecture composed single and multiple wavelength-bands with multi-wavelength labels, and analyze characteristics of two models. To avoid the packet collision in output ports of edge nodes due to output contention, the static and dynamic allocation scheme, which packets are allocated in time slots, is provided. Based on our analysis, it shows that delay only occur in not core nodes but edge nodes in the proposed architecture. In addition, we evaluate the probabilities of delay, packet loss, and call blocking in the proposed optical packet network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5B
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• pp.956-965
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• 2000

In this paper, we propose an efficient traffic grooming algorithm to minimize to number of SONET ADMs which is the dominant cost of system in high speed optical ring networks. It is an optimal traffic grooming algorithm to be applied to both unidirectional ring and bi-directional ring under both uniform traffic and nonuniform traffic. The proposed traffic grooming algorithm consists of two subalgorithms : one is the algorithm to construct full connection-rings as many as possible to minimize gaps by cutting the connections and using redirection method, and the other is the algorithm to groom connection-rings into a wavelength to maximize the number of shared nodes. The simulation results show that the proposed algorithm is superior to conventional algorithm under various network conditions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.9
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• pp.2219-2226
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• 2013

Optical phase conjugation combining with dispersion management (DM) is promising technique to compensate for signal distortion due to group velocity dispersion (GVD) and nonlinear Kerr effects in optical communication systems. However the fixed residual dispersion per span (RDPS) usually used in the optical links with OPC and DM restricts the flexible link configuration. In this paper, OPC links combining DM of the randomly distributed RDPS is proposed for implementing the flexible optical transmission network. It is confirmed that the excellent compensation in the optical links with the randomly distributed RDPS is obtained, limiting the launch power of WDM channels to the relatively low. It is also confirmed that the relatively high launch power WDM channels are effectively transmitted through the optical links with the randomly distributed RDPS of averaged 50 - 100 ps/nm.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11C
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• pp.64-74
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• 2001

In this paper, a dynamic minislot reservation protocol(DMRP) is proposed and analyzed to improve the performance of the multicast traffic processing in wavelength division multiplexing(WDM) networks. For the proposed protocol analysis, the WDM network architecture with a passive star coupler is used. One pair of transceiver is used for a control channel and the ocher pair of transceiver with one fixed transmitter and one tunable receiver are used for data transmission. In this protocol. the packets which fail to have successful transmission in the present time slot due to data channel and destination collisions, have priority to have successful reservation in the contention-less minislots of the next time slot. Therefore, protocols have improved the throughput and the system delay performance caused by the reduced probabilities of control channel contentions and destination collisions probability. Today, the efficient protocol that can handle the various types of data traffic is needed. As results, the DMRP is useful to improve the performance of throughput and system delay characteristics regardless of the kinds of traffic.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1B
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• pp.109-116
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• 2004

Optical Burst Switching (OBS) technology has drawn much attention as a promising solution for IP/WDM networks. OBS has the features such as the offset time, the delayed reservation and the burst assembly. In particular, the burst assembly, which assembles IP packets into the data bursts, has a great impact on the performance of OBS network. In this paper, we compare the performance of three different burst assembly schemes and investigate their impact on the performance of OBS network.

• Journal of Communications and Networks
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• v.9 no.1
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• pp.93-104
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• 2007

Traffic grooming, in which low-rate circuits are multiplexed onto wavelengths, with the goal of minimizing the number of add-drop multiplexers (ADMs) and wavelengths has received much research attention from the optical networking community in recent years. While previous work has considered various traffic models and network architectures, protection requirements of the circuits have not been considered. In this paper, we consider survivable traffic grooming, or grooming traffic which contains a mix of circuits that need protection and that do not need protection. We assume a unidirectional ring network with all-to-all symmetric traffic with $t\geq1$ circuits between each node pair, of which s require protection. As it turns out, survivable traffic grooming presents a significant tradeoff between the number of wavelengths and the number of ADMs, which is almost non-existent in non-survivable traffic grooming for this type of traffic. We explore this tradeoff for some specific cases in this paper. We also present some new results and solution methods for solving certain non-survivable traffic grooming problems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7C
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• pp.641-652
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• 2002

We introduce a new ultra-large capacity time- and wavelength-division hybrid optical switching system, called ESCIMONET(Easily SCalable Interconnected Multiwavelength Optical NETwork). We describe its architecture, principle of operation, and performance characteristics. ESCIMONET is very effective system in terms of its handling capacity versus number of wavelength needed. It can handle n$^3$number of channels using only n number of different wavelengths. The insertion loss of the whole system is less than conventional optical switching system so that the number of optical amplifiers in the system can be minimized. We analyzed the performance of the system by investigation the characteristics of the buffer used in the system such as throughput and average waiting time of the signal in a buffer.