An upgrade to a widely used specification for fibre optic cables will
allow the simpler deployment of Gigabit Ethernet (GbE) in FTTH
applications up to 500 m link distance. The original Recommendation
ITU-T Rec G.651 provided specifications for multimode fibre which is
currently widely deployed for data communications, but not for telecoms.
The work was initiated given two observations; the cost disparity
between telecom and data networks, where high speed GbE telecom
equipment is often far more expensive than datacom equipment; and the
economics of rolling out FTTH into multi-tenant (apartment) buildings
where there is a high subscriber density. Ethernet is increasingly seen
as an end-to-end technology.
Similar to recently published Rec G.657 on single mode fibre,
Recommendation G.651.1 allows for increased cable flexibility. This
increased flexibility in a fibre optic cable means that operators can
follow tighter corners in buildings and can worry less if cables /
fibres are laid with a sharp bend. This all makes installation work more
engineer friendly leading also to less re-work. Moreover the closures
for fibres can be half the size, important where space is at a premium
especially in multi-tenant buildings.
G.651.1 retains many of the key characteristics of its well known
predecessor. However manufacturing tolerances and transmission
characteristics have been improved significantly. In addition, it has
been harmonized fully with relevant IEC standards.