Calculating Insertion Losses For Unlike Fibers - 3Com CoreBuilder 7000 Installation & Start?Up Manual

Calculating Insertion
Losses for Unlike
Fibers
Table 25 Standard Multi-mode Fiber Specification (continued)
Maximum distance between nodes
Output power (from transmitter)
Receive power
*Maximum attenuation includes cable attenuation and the loss induced
by other components such as connectors, splices, and the mating of
unlike fiber types. Although some 2 km cable plants have a total
attenuation of less than 11.0 dB, the 2 km interstation distance must be
maintained to comply with modal bandwidth requirements.
Table 26 Alternate Multi-mode Fiber Types
Core ( µ m)
50
50
85
100
If unlike fibers are mated in the cable plant, calculate insertion losses to
be certain that the cable plant does not exceed the maximum attenuation
value listed in Table 25. To calculate the insertion loss, consider the types
of fiber in the cable plant and the connectors or splices used to join them.
Compare the result to the maximum attenuation value listed in Table 25.
If the result is greater than the value in the table, use only like fibers in the
cable plant.
Refer to Table 27 for the insertion losses of the fibers themselves. Use
Table 28, which lists the losses for connectors, cables, and splices, if the
specifications for these components are not available.
Use Table 27 for fiber-to-fiber connections only, not for power launched
from a transmitter.
2 km
19 dB minimum
14 dB maximum
30 dB minimum sensitivity
14 dB maximum sensitivity
Cladding ( µ m)
125
125
125
140
ATM Cabling
Numerical Aperture
0.20
0.22
0.28
0.29
113