Next Generation Optical Access Network: Standardization Outline and Key Technologies for Co-existence with Legacy Systems

Abstract

Users are increasingly demanding broadband services, and fiber-to-the-home (FTTH) is the main technology to answer these demands. Gigabit-class passive optical network (PON) systems, IEEE802.3ah GE-PON [1] or ITU-T G.984 G-PON [2] have been widely deployed and used by many network operators. The number of FTTH users in Asia is increasing and has exceeded 30 million [3]. Especially in Japan the number of FTTH users surpassed the number of digital subscriber line (DSL) users in 2008. Recently, the number of FTTH users topped 15 million, and the ratio of FTTH services among broadband services went above 50 percent [4]. This means FTTH supports most Japanese broadband services. With the emerging applications such as multi-channel high-density television (HDTV) distribution, broad bandwidths wider than those of the current system will be required. To respond to wider bandwidth demand, several kinds of technologies such as 10-Gbps class time division multiplexing (TDM), wavelength division multiplexing (WDM) [5], optical code-division multiple access (OCDMA) [6] and orthogonal frequency-division multiple access (OFDMA) [7], [8] have been developed and discussed as next generation PON (NG-PON) technologies. As 10 Gb/s Ethernet [9], which was approved in 2002, has been already widely used and 10-Gbps TDM technologies have become mature, the 10-Gbps-class TDM PON system is the most attractive candidate for NG-PON systems. Therefore, standardization development organizations (SDOs) have been discussing 10-Gbps-class TDM PON standards. Recently, the IEEE802.3 committee approved the 10G-EPON standard [10] and ITU-T has been developing an XG-PON standard [11]. This paper reviews NG-PON standardization trends fo-