• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.4
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• pp.289-294
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• 2008

Affordable traffic capacity of each node in networks is expected to reach in Tb/s range in proportion to the rapid growth of Internet users. To transmit more than Tb/s per fiber pair, WDM should be used as well as existing TDM. To increase the capacity of transmission in WDM networks, there are two ways, increasing channel speed or channel quantity. To increase the channel quantity, there are two ways, narrow spacing or expanding transmission bandwidth. To expand bandwidth, ultra-broadband optical amplifier technology is necessary. In this paper, we introduce EDFA in effect at C/L band, FRA, and some optical amplifiers in effect at S band, and analyze the development trend of various amplification technologies.

• ETRI Journal
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• v.29 no.1
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• pp.116-119
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• 2007

In this letter, we design a collision resolution protocol for optical burst switching ring networks to avoid burst collision. We define the offset time condition for no burst transmission collision and manage the free time list of nodes for no burst reception collision. In order to improve the throughput, we use a fiber delay line, void-filling, and void-compression. This protocol does not require any additional procedures for bandwidth reservation such as centralized assignment of bandwidth, lightpath setup of WDM ring networks, or token capturing for the burst transmission. The simulation results show that the proposed protocol can achieve high throughput while saving 70% of wavelengths when compared to round robin with random selection, round robin with persistent, and round robin with non-persistent with only destination delay.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1369-1375
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• 2007

The recent, a large capacity of telecommunication networks is required in order to it is in proportion to capacity of information communication increase and to satisfy a demand because of the demand about Internet, a multimedia service of internet, Video of internet protocol(VoIP), Audio/Video streaming. As a result, DWDM(Dense Wavelength Division Multiplexing)technologies are emerging to be a prevailing the method of solving it without additional optical fiber network building and high-speed equipment. Therefore this thesis proposed the optical filter of fiber/multilayer slab coupled structure combining it to multilayer slab waveguide by polishing the cladding of one side of fiber to design the optical filter having these functions. When a separation distance of fiber and slab was $3{\mu}m$, The optical filter proposed as the simulation result was satisfied with a DWDM filter characteristic with FWHM of 0.1nm on TM mode and TE mode as 32nm polarization independence in a communication window of $1.3{\mu}m$ when center wavelength was each ${\lambda}_0=1.274755{\mu}m$ and ${\lambda}_0=1.30591{\mu}m$.

• The Journal of the Korea Contents Association
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• v.6 no.10
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• pp.153-162
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• 2006

The WDM/SCM-FTTH is an advanced optical access Network that can efficiently support various kinds of access network requirements using the WDM and SCM technologies in the near future. In this paper, we propose new network structures of the FTTH(Fiber To The Home) in the WDM(Wavelength Division Multiplexing) and WDM/SCM(Sub-Carrier Multiplexing) FTTH, and evaluate its performance with simulation results for the optical characteristics of the network and the dynamic allocation of bandwidth on demand of the users.

• Journal of Korean Institute of Industrial Engineers
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• v.24 no.4
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• pp.571-578
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• 1998

In this paper, we deal with a node weighted Steiner Ring Problem (SRP) arising from the deployment of Synchronous Optical Networks (SONET), a standard of transmission using optical fiber technology. The problem is to find a minimum weight cycle (ring) covering a subset of nodes in the network considering node and link weights. We have developed two mathematical models, one of which is stronger than the other in terms of LP bounds, whereas the number of constraints of the weaker one is polynomially bounded. In order to solve the problem optimally, we have developed some preprocessing rules and valid inequalities. We have also prescribed an effective heuristic procedure for providing tight upper bounds. Computational results show that the stronger model is better in terms of computation time, and valid inequalities and preprocessing rules are effective for solving the problem optimally.

• Journal of KIISE:Information Networking
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• v.36 no.4
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• pp.360-368
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• 2009

Recently, broadband access networks have been competitively deployed all over the world with the development of various multimedia services for such a network. ETRI(Electronics and Telecommunications Research Institute) built the FTTH(Fiber-To-the-Home) service center to develop a next-generation equipment and a high-quality service/platform as well as to promote domestic industry in the field of optical communication. The FTTH service center has a variety of test equipments such as FTTH standard testbed for a BMT(bench mark test), a network operation center, and IPTV service equipments. Also, ETRI deployed a new type of commercial optical access networks cooperating with ISP(Internet Service Provider). This paper presents the performance evaluation of FTTH E-PON(Ethernet Passive Optical Network) system as a platform for TPS(Triple Play Service) based on QoS(Quality of Service) and QoE(Quality of Expericence) issues. This FTTH E-PON system is successfully demonstrated as an optical access network system by commercial network service provider and the FTTH service center of ETRI.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.136-136
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• 2003

In fiber optic networks, system size and cost can be significantly reduced by development of optical components through planar optical waveguides. One important step to realize the compact optical devices is to develop planar optical amplifier to compensate the losses in splitter or other components. Planar amplifier provides optical gain in devices less than tens of centimeters long, as opposed to fiber amplifiers with lengths of typically tens of meters. To achieve the same amount of gain between the planar and fiber optical amplifier, much higher Er doping levels responsible for the gain than in the fiber amplifier are required due to the reduced path length. These doping must be done without the loss of homogeniety to minimize Er ion-ion interactions which reduce gain by co-operative upconversion. Sol-gel process has become a feasible method to allow the incorporation of Er ion concentrations higher than conventional glass melting methods. In this work, Er-doped $SiO_2$-A1$_2$ $O_3$ films were prepared by two different method via sol -Eel process. Tetraethylorthosilicate(TEOS)/aluminum secondary butoxide [Al (OC$_4$ $H_{9}$)$_3$], methacryloxypropylcnethoxysaane(MPTS)/aluminum secondary butofde [Al(OC$_4$ $H_{9}$)$_3$] systems were used as starting materials for hosting Er ions. Er-doped $SiO_2$-A1$_2$ $O_3$ films obtahed after heat-treating, coatings on Si substrate were characterized by X-ray din action, FT-IR, and N-IR fluorescence spectroscopy. The luminescence properties for two different processing procedure will be compared and discussed from peak intensity and life time.

• ETRI Journal
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• v.35 no.2
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• pp.245-252
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• 2013

In this work, we study the physical layer solutions for 10-gigabit-capable passive optical networks (PONs), particularly for an optical link terminal (OLT) including a 10-Gbit/s electroabsorption modulated laser (EML) and a 2.5-Gbit/s burst mode receiver (BM-Rx) in a novel bidirectional optical subassembly (BOSA). As unique features, a bidirectional mini-flat package and a 9-pin TO package are developed for a 10-gigabit-capable PON OLT BOSA composed of a 1,577-nm EML and a 1,270-nm avalanche photodiode BM-Rx, including a single-chip burst mode integrated circuit that is integrated with a transimpedance and limiting amplifier. In the developed prototype, the 10-Gbit/s transmitter and 2.5-Gbit/s receiver characteristics are evaluated and compared with the physical media dependent (PMD) specifications in ITU-T G.987.2 for XG-PON1. By conducting the 10-Gbit/s downstream and 2.5-Gbit/s upstream transmission experiments, we verify that the developed 10-gigabitcapable PON PMD prototype can operate for extended network coverage of up to a 40-km fiber reach.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1641-1646
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• 2006

This paper deals with a physical access network design problem arising from the deployment of fiber-to-the-home passive optical networks (FTTH-PON). The problem seeks to find an optimal location and capacity assignment of splitters in the network such that the total cost of fiber and splitter is minimized, while satisfying all the demand. We propose tabu search approach for finding a good feasible solution.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.253-256
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• 2005

In this paper, we explain a various fiber to the home technology and give some important standardization status. And, passive optical networks which are WDM-PON, Ethernet PON and/or Gigabit-PON will be mainly deployed in populated subscriber area and multiple dwelling units with taking great advantage of OPEX. And finally we discuss FTTH deployment strategy with low capital cost.