Series Fibre Optic
Optical fibre cannot survive in the world on its own. It
must be packaged in a manner suitable for its environment.
Tensile strength, ruggedness, durability, flexibility, size, and
resistance to the environment are important considerations when
choosing a fibre optic cable.
General Cable offers 3 methods of construction to protect the
fibres:
Distribution Type (D Type)
Breakout Type (B Type)
Loose Tube
Distribution type:
In a Distribution type cable each individual fibre is has an
extruded PVC material placed over it. Some specifications will
refer to this as a 900μm tight-buffered fibre. These individual
tight-buffered fibres are colour coded for easy identification.
The buffer provides each individual fibre with protection from
the environment as well as physical support. The individual
fibres are cabled together and aramid yarn is applied as the
primary strength member. An overall sheath is then applied.
These cables are excellent for indoor use. They do not provide
the best moisture and environmental protection and therefore are
not recommended for outdoor applications.
Breakout type:
In a Breakout type cable each tight buffered fibre is
individually strengthened with aramid yarn, then PVC sheathed.
This allows for easy separation, breakout and direct termination
into connectors. The individually strengthened units are then
stranded and overall sheathed.
These cables are designed for intrabuilding and computer
backbone applications offering rugged individual fibre
protection. They are suitable for both horizontal and vertical
(up to 500m) installations.
Loose type
A loose tube is a hollow, plastic tube, which contains 1 to 12
optical fibres. The tube is large enough so that the fibres are
free to move around. The tube is filled with a gel to prevent
water penetration. The rigidity of the loose tube, combined with
the gel filling provides the best level of protection for the
fibres.
A loose tube cable consists of a number of loose tubes stranded
around a central strength member. The cable is then covered with
a protective sheath.
A loose tube cable provides a strain free environment for the
fibres. This means the cable can be subject to worst case
situations involving tension, temperature and crushing, without
the fibres suffering any stress. This ensures the attenuation
and bandwidth will remain stable and the fibres lifetime will
not be shortened.
These cables are designed for long haul communication circuits
where direct burial or installation in ducts is required