Page 88 - Optical Communications Essentials

Optical Fiber Cables

78 Chapter Five

Figure 5.10. Fiber optic underwater cable.

5.4.4. Military cable
Extremely strong, lightweight, rugged, survivable tight-buffered cables have
been designed for military tactical field use. That means they need to be
crush-resistant and resilient so they can withstand being run over by
military vehicles, including tanks, and they need to function in a wide range
of harsh environments. In addition, since often they are deployed in the field
from reels attached to the back of a rapidly moving jeep, they must survive
hard pulls. As a result of being developed for such hostile environments,
these cables also have found use in manufacturing, mining, and petro-
chemical environments. Figure 5.11 shows a two-fiber military distribution
cable. This consists of two color-coded tight-buffered fibers surrounded by
aramid yarn and encapsulated in a polyurethane (PU) jacket. Cable sizes
with up to 24 fibers are possible with standard lengths ranging from 300 m to
2 km.

5.5. Fiber and Jacket Color Coding
If there is more than one fiber in an individual loose tube, then each fiber is
designated by a separate and distinct jacket color. The ANSI/TIA/EIA-598-A
standard, Optical Fiber Cable Color Coding, prescribes a common set of fiber
colors. Since nominally there are up to 12 fiber strands in a single loose tube,
strands 1 through 12 are uniquely color-coded, as listed in Table 5.3. If there
are more than 12 fibers within an individual loose tube, then strands 13

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