This Recommendation describes flexible access networks using optical fibre technology. The focus is primarily on a network supporting services with bandwidth requirements ranging from that of voice to gigabit-per-second data services. Also included are distributive services.

This Recommendation describes characteristics of the physical media dependent (PMD) layer of an optical access network (OAN) with the capability of transporting various services between the usernetwork interface and the service node interface (SNI).

The OAN dealt within this Recommendation should enable the network operator to provide a flexible upgrade to meet future customer requirements, in particular, in the area of the optical distribution network (ODN). The ODN considered is based on a point-to-multipoint tree and branch option.

This Recommendation concentrates on the fibre issues: the copper issues of hybrid systems are described elsewhere, e.g., in Recommendations on any type of digital subscriber line (xDSL) (ITU-T G.99x-series).

This Recommendation focuses on additions to and modifications of earlier members of the ITU-T G.983.x series, which describe an architecture based on the asynchronous transfer mode (ATM) over a passive optical network (PON). The purpose of the additions and modifications are to support higher data rates, especially for the transport of data services.

This Recommendation proposes the physical layer requirements and specifications for the PMD layer of a gigabit-capable passive optical network (GPON). The transmission convergence (TC) layer and ranging protocol specifications for GPON systems are specified in [ITU-T G.984.3].