Juniper ACX1000 Hardware Manual page 91

Table 23: Estimated Values for Factors Causing Link Loss
Link-Loss Factor
Modal and chromatic dispersion
Faulty connector
Splice
Fiber attenuation
The following sample calculation for a 2-km-long multimode link with a power budget (P
the estimated values from
attenuation (2 km @ 1 dB/km, or 2 dB) and loss for five connectors (0.5 dB per connector, or 2.5 dB) and
two splices (0.5 dB per splice, or 1 dB) as well as higher-order mode losses (0.5 dB). The power margin
(P ) is calculated as follows:
M
P = P – LL
M B
P = 13 dB – 2 km (1 dB/km) – 5 (0.5 dB) – 2 (0.5 dB) – 0.5 dB
M
P = 13 dB – 2 dB – 2.5 dB – 1 dB – 0.5 dB
M
P = 7 dB
M
The following sample calculation for an 8-km-long single-mode link with a power budget (P
uses the estimated values from
fiber attenuation (8 km @ 0.5 dB/km, or 4 dB) and loss for seven connectors (0.5 dB per connector, or
3.5 dB). The power margin (P
P = P – LL
M B
P = 13 dB – 8 km (0.5 dB/km) – 7(0.5 dB)
M
P = 13 dB – 4 dB – 3.5 dB
M
P = 5.5 dB
M
Estimated Link-Loss Value
Single mode—None
Multimode—None, if product of bandwidth and distance is less than 500 MHz-
km
0.5 dB
0.5 dB
Single mode—0.5 dB/km
Multimode—1 dB/km
Table 23 on page 82. This example calculates link loss (LL) as the sum of fiber
Table 23 on page 82. This example calculates link loss (LL) as the sum of
) is calculated as follows:
M
(Continued)
83
) of 13 dB uses
B
) of 13 dB
B