Introduction

Optical fibre access to the user, the so-called Fibre-to-the-Home (FTTH), is becoming a mature concept and a reality in many regions of the globe, with more than 8 millions homes already connected, in an exponential growth. As it is widely accepted, FTTH is the only future-proof technology that will be able to support the upcoming interactive multimedia services, and nowadays operators are planning to substitute the existing telephone-line-based systems (Asymmetric Digital Subscriber Line ADSL, Plain Old Telephone Service POTS) or cable systems (Cable Television CATV) per optical fibre. First, point-to-point fibre links; recently, the more advanced point-to-multipoint Passive Optical Networks (PON) are being deployed to implement FTTH — currently in Asia and USA mainly. The first generation PONs (Broadband PON, Gigabit PON, Ethernet PON) have been recently standardized, offering symmetrical Gigabit/s bandwidth typically shared among few tens of users.

This document focuses onto discussion of the technical options for next generation PONs (ngPONs) and aims at proposing and analyzing new architectures as well as enabling technologies. True-broadband access (10/100 Mbps) may drive the telecommunications sector again towards relevant positions in terms of social and economic development. If -with the advanced techniques proposed- operators can implement a gradual upgrade-path to their infrastructure from a basic one that is probably already deployed to an all-optical network, the development can be effectively done.

The main focus of the report is on very high-density scalable broadband-for-all access networks, for scenarios where the scalability and the continuous growth of the fibre network is an essential requirement for the operator business plan. This may occur in fibre-limited or saturated areas and also where the long term cost effectiveness drives a green-field deployment. Thus, current approaches like current point-to-point fibre-rich plants or standardized Time Division Multiplexed (TDM) PONs (GPON, EPON) are not extensively dealt within this text, which mainly focuses on longer-term generations of PONs.