Network Cable And Transceiver Planning; Table 23: Estimated Values For Factors Causing Link Loss - Juniper ACX2200 Hardware Manual

Table 23: Estimated Values for Factors Causing Link Loss

Link-Loss Factor
Higher-order mode losses
Modal and chromatic dispersion
Connector
Splice
Fiber attenuation
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Estimated Link-Loss Value
Single-mode—None
Multimode—0.5 dB
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
The following sample calculation for a 2-km-long multimode link with a power budget
(P ) of 13 dB uses the estimated values from
B
(LL) as the sum of fiber 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
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 ) of 13 dB uses the estimated values from
B
(LL) as the sum of 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
follows:
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
In both examples, the calculated power margin is greater than zero, indicating that the
link has sufficient power for transmission and does not exceed the maximum receiver
input power.
Chapter 11: Network Cable and Transceiver Planning
Table 23 on page 51 to calculate link loss
) is calculated as follows:
M
Table 23 on page 51 to calculate link loss
) is calculated as
M
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