Loose Buffer And Tight Buffer

There are two major types buffers : loose and tight, Cross sections of both types are important in cable structures .

A loose buffer's inner  diameter is much larger than a fiber's outer(coating) diameter. Two major advantages stem from this design: perfect fiber isolation from mechanical forces(within some given range, of course) and protection from moisture. The first advantage comes from a so-called mechanical dead zone: A force imposed on a buffer does not affect the fiber until this force becomes large enough to straighten the fiber inside the buffer. Aloose buffer can be easily filled with a water-blocking gel, which provides its second advantage. In addition, a loose buffer can accommodate several fibers reducing the cost of the cable . On the other hand , this type of cable can't be installed vertically and its end preparation for connectorization(splicing and termination) is labor-intensive. Consequently, the loose-buffer type of cable is used mostly in outdoor installation because it provides stable and reliable transmission over a wide range of temperatures , mechanical stress. and other environmental conditions .

A tight buffer's inner diameter is equal to the fiber's coating diameter. Its primary advantage is its ability to keep cable operational despite a break in the fiber. Since a buffer holds a fiber firmly, a small separation of the fiber ends won't interrupt the service  completely, although it will definitely degrade signal quality. This is why the military was the first customer -and still is the largest -for this type of fiber cable. A tight buffer is rugged allowing a smaller bend radius. Since each buffer contains only one fiber and there is no gel to be removed. it's easy to prepare this cable for connectiorization. Cables having a tight buffer can be installed vertically . In general, tight-buffer cables are more sensitive to temperature and mechanical and water impacts than loose-buffer cables ; hence , they are recommended mostly for indoor applications . On the other hand, tight-buffer cables designed for specail applications (such as military and undersea) are the strongest cables available .