The FSAN consortium, through its Next Generation Access (NGA) task group, is exploring different technologies to evolve optical access systems beyond GPON. The two main candidates are 10G PONs and WDM-PONs. 10G PONs enable one wavelength to carry 10Gbps capacity, which is shared in the same way as existing point-to-multipoint PON architectures. WDM-PONs allow multiple wavelengths to be carried over a single strand of fibre through the use of different frequencies.
One scenario of a WDM-PON is that a customer could receive a dedicated wavelength. How much data capacity each wavelength could optimally carry in relation to cost, as well as the practical number of wavelengths that a WDM-PON could support, are some of the key issues that the FSAN is exploring.
NTT views WDM-PON as the most-promising next-generation FTTH system, not least because of its potential to allow BPON and EPON to share the same fibre. Korea Telecom has already started trials of WDM-PON.
According to vendors, standardisation work on 10G PON could be completed by 2009 with commercial products available by 2011. A similar timetable is envisaged for WDM-PONs.
It is unlikely that the emergence of 10G PON or WDM-PON will signal the end of the GPON versus EPON debate. In March 2006, a 10G EPON study group was formed within the IEEE 802.3 working group to explore the possibility of a 10Gbps wavelength over an EPON architecture.