ITU-T G.984.6 PDF

This Recommendation concerns GPON systems with optical link budgets up to the logical limits of the transmission convergence (TC) layer. The increased optical capability, which includes both increased overall fibre length and increased overall splitting ratio, is referred to in this Recommendation as "reach extension". The primary concerns addressed are the increase of the loss budget and the management of optical impairments.

This Recommendation considers mid-span extension, which uses an active extension node placed in the middle of the optical network. The recommended parameters for the ODN(s) involved in this scheme are specified. Single-sided extension is considered as an improvement to the OLT interface, and is described in [ITU-T G.984.2] as amended.

The systems considered here must remain compatible with existing ONTs. Furthermore, the approaches should maintain compatibility with existing OLTs to the maximum extent possible. It is recognized that some modification of the OLT equipment may be necessary, but this should be minimized.

Two system architectures are considered: optical amplification, and opto-electronic regeneration. These can be viewed as providing reach extension at the physical layer. The key interfaces and functional blocks in each of these architectures are identified and specified.