FTTH: The Overview of Existing Technologies Dawid Nowak a and John Murphy b a School Of Electronic Engineering, Dublin City University, Dublin 9, Ireland b Department of Computer Science, University College Dublin, Dublin 4,Ireland ABSTRACT The growing popularity of the Internet is the key driver behind the development of new access methods which would enable a customer to experience a true broadband. Amongst various technologies, the access methods based on the optical fiber are getting more and more attention as they offer the ultimate solution in delivering different services to the customers’ premises. Three different architectures have been proposed that facilitate the roll out of Fiber-to-the-Home (FTTH) infrastructure. Point-to-point Ethernet networks are the most straightforward and already matured solution. Different flavors of Passive Optical Networks (PONs) with Time Division Multiplexing Access (TDMA) are getting more widespread as necessary equipment is becoming available on the market. The third main contender are PONs with Wavelength Division Multiplexing Access (WDMA). Although still in their infancy, the laboratory tests show that they have many advantages over present solutions. In this paper we show a brief comparison of these three access methods. In our analysis the architecture of each solution is presented. The applicability of each system is looked at from different viewpoint and their advantages and disadvantages are highlighted. Keywords: Access Networks, Optical Networks, Fiber-To-The-Home 1. INTRODUCTION Introducing the fiber in the local loop was envisaged nearly 20 years ago. 1–3 As the quality of the optical fiber was improving, efficient transmitters and receivers appeared, it seemed possible to build an access network that would be based on the optical technology. Due to the lack of active units in the light path the architecture of the system was simple, cost effective and offered bandwidth that was not, and still is not, possible to achieve by other access methods. However, the initial progress in the development of optical networks was slowed to a halt by economical and technological factors. The Internet was not as widespread then as it is now and customers were not ready to pay for the broadband access. It was envisaged that a narrow band Integrated Services Digital Network access would be sufficient for most of the users until year 2010 4 and only handful of business customers would need broadband access. Rapid progress in development of different types of the Digital Subscriber Loop (DSL) technology and its widespread adoption in the nineties was another factor impeding the deployment of FTTH. As the average transfer rate of 6 Mbps could be achieved over DSL, the cost of replacing existing copper infrastructure with optical cables was not justified from the economical point of view. In recent years there has been a new interest in access methods based on the optical fiber. A couple of major factors are behind the motivation to revive this powerful idea. From the social point of view the Internet has become phenomenally popular and the number of customers requiring broadband access and willing to pay for it is increasing steadily despite the slumps in the global economy. 5 New services such as High Definition Television (HDTV) have been developed that require more bandwidth that can be provided by DSL or Cable Modems. Moreover, a further growth in the number of people requiring broadband access is forecasted. Much of the current development of broadband networks based on the optical technology has been achieved as a result of an active and stimulating role of governmental agencies. They are responsible for implementing policies that E-mail: {nowakd,murphyj} @ eeng.dcu.ie