Recent advances in optical access technologies

Fiber to the home (FTTH) is now the most popular fixed Internet access service in Japan; it has been attracting far more customers than ADSL since early 2005. Gigabit-capable passive optical networks (PONs) have been proven to be the most promising approach since they realize not only point-to-multipoint bidirectional connections for broadband data communication but also video distribution in a very cost effective manner. This paper first reviews such PON technologies as well as other optical technologies to support the massive deployment of these PONs in terms of further reducing the cost, especially with regard to operation/installation and to further increasing user friendliness towards the full-scale FTTH era. It next discusses possible technical directions for future optical access networks (OANs), and review recent research towards them. Wavelength-division multiplexing (WDM) is one of the important technologies in realizing the future OANs.