• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.7
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• pp.1354-1358
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• 2007

Nowaday, the wideband multimedia service, high speed and great capacity internet service etc. are increasing, so the network construction with the base of optical subscriber network is necessary. As efficient and economic optical subscriber networks are developed, so efficient network construction is possible. The most technology of them is WDM(Wavelength Division Multiplexing)-PON technology of ONU(Optical Network Unit) jointing method using PON(Passive Optical Network). In this paper, we have studied on a method for automatic optimization of data modulation current as optical power when the data is transmitted.

• Journal of the Korea Society of Computer and Information
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• v.17 no.8
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• pp.51-60
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• 2012

I propose the 5Gbps/1.25Gbps WDM/TDM hybrid Passive Optical Network(PON) with inverse RZ(Return to Zero) code coded downstream and NRZ(Non Return to Zero) upstream re-modulation and analyze its performance by performing simulation with MATLAB. The results have shown that an optical line termination (OLT) can be connected to 8, 16 optical network unit (ONU)s with the Bit Error Rate(BER) of $10^{-9}$ when the distance between OLT and ONU is 10Km and transmitted optical powers are more than -3.8, -0.9dBm, respectively. The proposed WDM/TDM hybrid PON system can solve the problem of data rate limit in upstream which happened in the conventional TDM PON because the upstream data rate is proportional to ONU and does not require a light source in ONU and its control circuits in OLT, thus can be a useful technology for asymmetric optical subscriber networks.

• 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.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.292-295
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• 2008

We propose a PON repeater system which transports multiple PON channels at the same time over the physical limit of the standard E-PON reach. To increase the physical reach up to 60km, we used the O-E-O (optic-electric-optic) signal regeneration on an active remote terminal which is placed between a central office and passive remote nodes. Also, by incorporating the well-established WDM technology to aggregate multiple E-PON channels, we successfully increased the split ratio (the number of subscribers per fiber core) to over 256.

• Journal of Communications and Networks
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• v.15 no.5
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• pp.538-542
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• 2013

This paper proposes a broadcast software download (BSD) scheme for a 10-gigabit-capable passive optical network (XG-PON), which dramatically reduces the time required to update a remotely-located user terminal's software. The performance of the proposed BSD is examined by numerical analysis and demonstrated by experimental verification on our XG-PON test platforms. The results show that the BSD takes less than 5 minutes to update 45 user-terminal software, while the conventional unicast software download scheme normally takes more than one and half hours.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.406-408
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• 2005

A passive Optical Network (PON) is famous for the most cost-efficient solution among the optical networks. This is because there is no active device between a central office and subscribers. A wavelength division multiplexing (WDM) offers each subscriber to feel unlimited bandwidth. A WDM-PON, however, has a cost problem that WDM-PON is used commercially. To solve this trouble, it is surveyed that a Sub-Carrier Multiplexing (SCM) used in a WDM-PON increases the number of subscribers. The performance of WDM/SCM-PON varies with various noises. The several FEC Codes can reduce the effects of noise and improve the performance of the system. Thus, Choosing a suitable FEC code is important work. This paper describes that a Reed-Solomon (RS) code is the most suitable code for WDM/SCM-PON at the object of 100 Mbps and $10^{-9}$ BER

• Journal of the Korean Operations Research and Management Science Society
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• v.36 no.2
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• pp.1-14
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• 2011

In this paper, we deal with an access network design problem of fiber-to-the-home passive optical network (FTTH-PON). The FTTH-PON network design problem seeks to minimize the total cost of optical splitters and cables that provide optical connectivity between central office and subscribers. We develop a flow-based mixed integer programming (MIP) model with nonlinear link cost. By developing valid inequalities and preprocessing rules, we enhance the strength of the proposed MIP model in generating tight lower bounds for the problem. We develop an effective Tabu Search (TS) heuristic algorithm that provides good quality feasible solutions to the problem. Computational results demonstrate that the valid inequalities and preprocessing rules are effective for improving the LP-relaxation lower bound and TS algorithm finds good quality solutions within reasonable time bounds.

• 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.

• ETRI Journal
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• v.38 no.1
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• pp.1-8
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• 2016

A large incoherent crosstalk (IC) caused by amplified spontaneous emission (ASE) noise power from Tx-disabled optical network units and a differential path loss has been shown to degrade upstream transmission performance in time-division multiplexing passive optical networks. This paper considers the IC-induced power penalty of an upstream signal both in an XG-PON and in a TWDM-PON. We investigate the degradation of the extinction ratio and relative intensity noise through a simulation and experiments. For the XG-PON case, we observe a 9.6 dB difference in the level of ASE noise power from Tx-disabled ONUs (hereafter known simply as ASE noise) between our result and the ITU-T XG-PON PMD recommendation. We propose an optical filtering method to mitigate an IC-induced power penalty. In the TWDM-PON case, the IC-induced power penalty is naturally negligible because the ASE noise is filtered by a wavelength multiplexer at the optical line terminal. The results provide design guidelines for the level of ASE noise in both XG-PONs and TWDM-PONs.

• ETRI Journal
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• v.27 no.3
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• pp.334-336
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• 2005

We improved the performance of the spectrum-sliced light source for wavelength-division-multiplexed passive optical networks by employing a Fabry-Perot laser diode(FP-LD). We found that the FP-LDs can suppress the intensity noise as significantly as using a gain-saturated semiconductor optical amplifier. The transmission characteristics were measured and analyzed in both conditions with and without employing an FP-LD.