Table 23: Estimated Values For Factors Causing Link Loss - Juniper M10i Hardware Manual

M10i Internet Router Hardware Guide
Factors that can cause link loss include higher-order mode losses, modal and
chromatic dispersion, connectors, splices, and fiber attenuation.
186 lists an estimated amount of loss for the factors used in the following sample
calculations. For information about the actual amount of signal loss caused by
equipment and other factors, refer to vendor documentation.

Table 23: Estimated Values for Factors Causing Link Loss

The following example uses the estimated values in
link loss (
The power margin (
P M = P B
P M = 13 dB
P M = 13 dB
P M = 6 dB
The following sample calculation for an 8 km-long single-mode link with a power
budget (
link loss (
186
Network Cable Specifications and Guidelines
Link-Loss Factor
Higher-order mode losses
Modal and chromatic dispersion
Connector
Splice
Fiber attenuation
) for a 2 km-long multimode link with a power budget (
LL
Fiber attenuation for 2 km @ 1.0 dB/km= 2 dB
Loss for five connectors @ 0.5 dB per connector = 5(0.5 dB) = 2.5 dB
Loss for two splices @ 0.5 dB per splice =2(0.5 dB) = 1 dB
Higher-order loss = 0.5 dB
Clock recovery module = 1 dB
) is calculated as follows:
P M
LL
2 km (1.0 dB/km)
2 dB 2.5 dB
P B ) of 13 dB uses the estimated values from
) as the sum of fiber attenuation (8 km @ 0.5 dB/km, or 4 dB) and loss
LL
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
Table 23
5 (0.5 dB) 2 (0.5 dB)
1 dB 0.5 dB 1 dB
Table 23
Table 23 on page
on page 186 to calculate
) of 13 dB:
P B
0.5 dB [HOL] 1 dB [CRM]
on page 186 to calculate