“…Several options including the WDM-PONs (Kani, 2010;Grobe and Elbers, 2008), hybrid TDM/WDM-PONs (Hyun et al, 2010), FiWi (Ghazisaidi and Maier, 2011;Tsagklas and Pavlidou, 2011), Advanced Modulation Techniques (AMTs) (Kamijoh et al, 2009;Chang et al, 2009), TDM-Based LR-OANs ( Van de Voorde et al, 2000;Shea and Mitchell, 2007b), TDM/CWDM-Based LR-OANs and TDM/DWDM-Based LR-OANs (Talli and Townsend, 2006;Shea and Mitchell, 2007c;Jung et al, 2012;Syuhaimi et al, 2013) were reviewed. Although many of these proposed architectures are interesting from the technical perspective, the cost, bandwidth per user and the number of accommodated subscribers remain the dominant factors for commercial success.…”