Cheoul-Shin Kang

Fiber-optic matched filters with metal films deposited on fiber delay-line ends for optical packet address detection

We fabricated compact fiber-optic matched filters by directly depositing metal thin films on fiber delay-line ends. Average reflectance of the metal film was measured to be 88% in the wavelength region of 1400-1600 nm. Detection of 10 Gb/s, 8-b optical packet addresses has been successfully demonstrated using the matched filters composed of four metal-coated fiber delay lines and three fused biconically tapered fiber couplers. Experimental results on correlation outputs of the matched filters showed an excellent agreement with those of theoretical analyzes.

A broadband ring network: multichannel optical slotted ring

Abstract This paper presents a multichannel optical ring network for broadband integrated services. The network uses a multichannel architecture with wavelength division multiplexing (WDM) and photonic packet switching devices for its access mechanism. The electronic speed bottleneck is removed out of the ring, which allows utilization of the full bandwidth for the optical fiber transmission medium. For compatibility with B-ISDN, the network uses a similar cell structure to that of an ATM based cell with a slotted ring concept. Fiber optic delay line matched filters are used as a means of address detection at the destination nodes. The network architecture is described and a design of the optical switching node is presented. A novel technique is devised in order to measure the average transfer delay of a cell in the multichannel slotted ring network. The analytical results show an excellent agreement with simulation results over a broad range of parameters. The results show that the major part of the cell transfer delay is coming from the propagation delay from a source to a destination. It is also observed that the throughput characteristic of the network depends upon the aggregated transmission capacity of the network.

Performance comparison of a class of slotted ring networks

Much has been previously written about the performance of slotted ring networks. However, the results are not appropriate to apply for the new generation slotted rings, like counter-rotating multichannel slotted rings. In this paper, a novel technique for quantitative measurement of average transfer delay of a class of slotted rings is presented. The approach is expanded to compare the average transfer delay of various slotted rings including counter-rotating multichannel slotted ring networks. An extensive simulation study has been carried out to verify the derived analytical results. The analytical results show an excellent agreement with simulation results over a broad range of parameters. The average transfer delay of the counter-rotating slotted ring network is about half that of the conventional multichannel slotted rings. Spatial reuse using the counter-rotating channel configuration also increases the effective ring throughput significantly, compared to conventional simple multichannel ring networks. The results show that the major part of the cell transfer delay comes from the propagation delay from a source to a destination. It is also observed that the network throughput depends upon the aggregated transmission capacity of the network.

Photonic packet address detectors for optical ring networks

Two types of fiber optic reflectively tapped delay line matched filters are produced for use as photonic packet address detectors in an optical ring network. Dielectric films evaporated on cleaved fiber ends function as light taps for the filters. Experimental results and theoretical calculation on photonic packet address detectors with 1 Gbps address code of (101) are reported.

Photonic packet switching device for WDM-based optical ring networks

A photonic packet switching device is designed for WDM based optical slotted ring networks which are suitable for B-ISDN access network and LAN/MAN. For the design, we devised a fiber optic delay line matched filter as a means of address filtering at the destination node and developed an efficient address decoding algorithm to accommodate the maximum available number of nodes in the ring network. Based on the algorithm, the maximum available number of node addresses in the ring is 3,432 for the case of 16-bit address. The design objectives of the photonic packet switching device are to eliminate the optical-to-electrical conversion at the address processing, to remove optical data from the ring at the destination nodes so that the slots can be reused a number of times in a rotation, and to be compatible with B-ISDN based on ATM concerning services, bit rate, interface, and switching node. The network architecture using the photonic packet switching device is also described. The simulation results show that the major part of the cell transfer delay in the network is coming from the propagation delay from a source to a destination. It was also observed that the average transfer delay characteristic of the network depends upon the aggregated transmission capacity of the network.

Automatic repeat protocol for distribution automation system through powerline communication

A communication network plays an important role in distribution automation system(DAS). In this paper, a powerline communication network which might span geographically 5-50 km using a bus or tree topology has been introduced. In the powerline communication networks, data signal cannot travel long distance because of attenuation, noise, and distortion. Consequently, we need to insert a number of repeaters into the network to recover the signal power, which causes the flooding problem in the network and lowering of the network performance. In this paper, to solve the flooding problem, an automatic repeat MAC protocol has been devised and applied to a powerline communication network in order to form a composite communication network for DAS. A mathematical performance analysis has been carried out to measure the performance characteristics of the proposed protocol applied to various powerline communication network environments. We also designed a powerline communication network simulator to verify the mathematical results. The results of the mathematical analysis and the simulation estimate the performance of the powerline communication network to which the proposed protocol applied.

Performance Evaluation and Modeling for Korea Standard of PLC MAC

In this paper, we embody KS-MAC protocol based on Korea national standard (KS X 4600-1) Class A protocol with NS-2 simulator and verify its performance. Also, we develop optimized high speed MAC in medium-voltage and propose efficient topology. Compared with experiment results and simulated results are quite analogous. With help of this simulation, when construct network with multi-node, we easily calculate bandwidth and delay of the individual node for more efficient way of utilizing When high speed PLC network is constructed, this simulation expects PLC technology to develop in response to various conditions and results.

A quantitative performance comparison study of all-optical slotted rings with different packet header speeds

For full utilization of the high transmission bandwidth of optical fiber, several optically transparent switching nodes have been proposed for use in photonic LANs, MANs or B-ISDN access networks. In the switching nodes, payload speed is transparent to optical speed while header speed remains at 155Mbps or 622Mbps for address processing by node control electronics. Another type of photonic packet switching node with optical signal processing for address detection supports higher header speed in packet transmission. In this paper, we analyze the performances of the optical ring networks which utilize the photonic packet switching nodes. A quantitative performance comparison study is carried out to observe the effect of header speed on the optical ring network performance.

A quantitative performance comparison study of optical ring networks with different header speeds

For the full utilization of the high transmission bandwidth of optical fiber, several optically transparent switching nodes are proposed for use in photonic LANs, MANs or B-ISDN access networks. The node design is simple and adaptable to various networks including rings, buses, and WDM networks. In this paper, we analyze the performance of the optical ring networks which utilize the photonic packet switching nodes. A quantitative performance comparison study is carried out to observe the effect of header speed on the optical ring network performance.

Fiber optic delay-line matched filters using metal film reflectors for optical packet address detection

Reflectively tapped fiber-optic delay-line matched filters with metal film reflectors evaporated on cleaved fiber ends have been fabricated. This novel device can provide ultra-high speed signal processing capability, small size, and low loss, and be used as an optical packet address detector for all-optical wavelength division multiplexing switching networks. Using the filters, detection of 2.5 Gb/s, 6-bit packet addresses for optical ring networks has been successfully demonstrated. Experimental and calculation results on correlation outputs of the filters are reported.