• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.155-158
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• 2001

A 640Gb/s high-speed ATM switching system that is based on the technologies of advanced MCM, 0.25um CMOS and optical WDM interconnection is fabricated for future N-ISDN services. A 40 layer, 160mm$\times$114mm ceramic MCM realizes the basic ATM switch module with 80Gbps throughput. The basic unit ATM switch module with 80Gb/s throughput. The basic unit ATM switch MCM consists of in 8 chip advanced 0.25um CMOS VLSI and 32 chip I/O Bipolar VLSIs. The MCM employs an 40 layer, very thin layer ceramic MCM and a uniquely structured closed loop type liquid colling system is adopted to cope with the MCM's high-power dissipation of 230w. The MCM is Mounted on a 32cm$\times$50cm mother board. A three stage ATM switch is realized by optical WDM interconnection between the high-performance MCM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1207-1215
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• 2009

The FTTH is known as an optimal solution to provide broadband services like IPTV and the W-PON is a good alternative to implement the FTTH. It is firstly commercialized in Korea but not widely deployed because of it's high price. In this paper, we suggest a wavelength integration method to drop the price and enhance the utilization of the W-PON. The method makes one logical channel with multiple wavelengths when the W-PON system has to accommodate a signal of which transmission rate is greater than the rate of a single wavelength. Accordingly, the system can accommodate any signal rate. We introduce a frame structure, suggest synchronization and clock recovery methods, and finally show actual applications for the Ethernet and the G-PON.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.4
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• pp.971-980
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• 2013

System performance improvement through the concentrated residual dispersion per span (RDPS) in special transmission fiber spans in optical transmission links with dispersion management (DM) for wavelength division multiplexed (WDM) transmission is investigated through the comparison with the performance in optical transmission links with uniform RDPS in every fiber spans. It is confirmed that, in optical links with RDPS of 0 ps/nm uniformly distributed in the rest fiber spans, if RDPS of 300 ps/nm and 1,320 ps/nm are concentrated in 5th-13th fiber spans and 6th-13th fiber spans, respectively, then the best performance is obtained. It is also confirmed that optimal net residual dispersion (NRD) controlled by precompensation and postcompensation are 10 ps/nm and -10 ps/nm, respectively, in all two cases, and the effective launching power range below 1 dB eye opening penalty (EOP) in the concentrated RDPS of 300 ps/nm and 1,320 ps/nm are improved by 2 dB and 6 dB than optical transmission links with the uniformly distributed RDPS, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5B
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• pp.842-849
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• 2000

In this paper, We analyzed the protocol to improve the performance of the multicast traffic processing in WDM networks. In the protocol, control channels are devided into contention-less minislots and contention minislots. And the packets which fail to have successful reservation in the present time slot have priority to have successful reservation in the contention-less minislots of the next time slot. Therefore, control channel contentions and destination conflicts can be reduced with the use of contention-less minislots. For the multicast traffic processing, the theoretical analysis and computer simulation are important to estimate the network performance and to calculate the optimized number of contention-less minislots. In this paper, the state transition probability of the number of contention-less minislots and arrival packets are calculated using 4-dimension matrix. The maximum number of contention-less minislots is equal to the number of channels for maximum performance improvement of the system. It is theoretical analysis and prove to computer simulation the performance of the protocol.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.5
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• pp.33-39
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• 2008

We have experimentally demonstrated the transmission performance of a feedforward optical transmitter using an external light injection technique. The feedforward compensation method shows 31 dB intermodulation distortion suppression and 2.2 dB noise reduction. A high side-mode suppression ratio exceeding 35 dB of the wavelength of the locked Fabry-Perot laser diode was obtained over 12 nm ranges. The suppression characteristics of the intermodulation distortion for various wavelength differences and transmission lengths were measured and analyzed as the evaluation criteria for the system performance in WDM/SCM based radio-over-fiber systems.

• Journal of Advanced Navigation Technology
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• v.23 no.3
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• pp.251-257
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• 2019

The configuration of ultra-long optical transmission link with dispersion management and optical phase conjugation is proposed. The whole transmission link consist of 80 km (single mode fiber span) ${\times}$ 56 fiber spans. The artificial distribution of single mode fibers' lengths and residual dispersions in fiber spans, which are gradually increased/decreased as the span number is increased, is adopted to compensate for the distorted wavelength division multiplexed channels. Since the compensation effect through the artificial distribution in the previous researches is expected to decrease as the number of fiber spans are increased, three-time repetition of the artificial distribution patterns at intervals of 9 fiber spans applied into the link with dispersion management and optical phase conjugation is proposed. From the simulation results, it is confirmed that the compensation in the link configured by the special distribution pattern among 4 proposed patterns is slightly improved than the link configured by the conventional method, which is designed by the repeat-less distribution pattern.

• Journal of the Optical Society of Korea
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• v.11 no.1
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• pp.44-48
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• 2007

A two-stage gain-clamped erbium doped fiber amplifier (GC-EDFA) using a pump laser diode and a 16 channel wavelength division multiplexing (WDM) with 0.8 nm spacing in C band of $1,545{\sim}1,560nm$ wavelength is experimentally demonstrated for a burst packet mode optical switching system.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.219-222
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• 2002

In this paper, we propose the OADM based on a Mach-Zehnder interferometer(MZI) with FBG(fiber Bra-gg grating) in the interferometer arms. The OADM us ing FBG and MZI is able to minimize system and red uce weight. We analyze output\ulcorner characteristics of OAD-M, and present the optimum design data through the computer simulation, and obtain the good experimental results. Also, the proposed OADM is suitable to DWD-M(Dense WDM) system because it has the narrow 1-inewidth.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.6
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• pp.257-263
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• 2005

WDM optical communication system requires wavelength division multiplexing, reverse multiplexing and optical filter. OADM is a device that can separate or combine specific wavelength of channel from the transmission line. This paper suggests OADM that uses 2 steps FBG based on MZI structure. The OADM that uses 2 steps FBG can minimize the system size and reduce the value of side lobe remarkably. The results obtained in this paper can be used for design and application of OADM that uses 2 steps FBG.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4B
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• pp.566-575
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• 2010

In recent, artificial immune system has become an important research direction in the anomaly detection of networks. The conventional artificial immune systems are usually based on the negative selection that is one of the computational models of self/nonself discrimination. A main problem with self and non-self discrimination is the determination of the frontier between self and non-self. It causes false positive and false negative which are wrong detections. Therefore, additional functions are needed in order to detect potential anomaly while identifying abnormal behavior from analogous symptoms. In this paper, we design novel network attack detection and response schemes based on artificial immune system, and evaluate the performance of the proposed schemes. We firstly generate detector set and design detection and response modules through adopting the interaction between dendritic cells and T-cells. With the sequence of buffer occupancy, a set of detectors is generated by negative selection. The detection module detects the network anomaly with a set of detectors and generates alarm signal to the response module. In order to reduce wrong detections, we also utilize the fuzzy number theory that infers the degree of threat. The degree of threat is calculated by monitoring the number of alarm signals and the intensity of alarm occurrence. The response module sends the control signal to attackers to limit the attack traffic.