Table 42: Estimated Values For Factors Causing Link Loss - Juniper EX9214 Hardware Manual

Table 42: Estimated Values for Factors Causing Link Loss

Link-Loss Factor
Higher-order mode losses (HOL)
Modal and chromatic dispersion
Connector
Splice
Fiber attenuation
Clock Recovery Module (CRM)
Copyright © 2015, Juniper Networks, Inc.
This means the link will work. A (P
to operate the receiver. See the specification for your receiver to find the maximum
receiver input power.
Before you begin to calculate the power margin:
Calculate the power budget. See
Power Budget" on page
To calculate the worst-case estimate for the power margin (P
Determine the maximum value for link loss (LL) by adding estimated values for
1.
applicable link-loss factors—for example, use the sample values for various factors
as provided in Table 42 on page 85
the (P ) is 13 dBm):
B
Estimated Link-Loss Value
Multimode—0.5 dBm
Single mode—None
Multimode—None, if product of
bandwidth and distance is less than
500 MHz/km
Single mode—None
0.5 dBm
0.5 dBm
Multimode—1 dBm/km
Single mode—0.5 dBm/km
1 dBm
NOTE: For information about the actual amount of signal loss caused by
equipment and other factors, see your vendor documentation for that
equipment.
Calculate the (P ) by subtracting (LL) from (P
2.
M
P – LL = P
B M
) that is zero or negative indicates insufficient power
M
"Calculating the EX Series Switch Fiber-Optic Cable
84.
(here, the link is 2 km long and multimode, and
Sample (LL) Calculation Values
This example assumes 5 connectors.
Loss for 5 connectors:
(5) * (0.5 dBm) = 2.5 dBm
This example assumes 2 splices. Loss for
two splices:
(2) * (0.5 dBm) = 1 dBm
This example assumes the link is 2 km
long. Fiber attenuation for 2 km:
1 dBm
):
B
Chapter 7: Planning Power Requirements
) for the link:
M
0.5 dBm
0 dBm
0 dBm
0 dBm
(2 km) * (1.0 dBm/km) = 2 dBm
(2 km) * (0.5 dBm/km) = 1 dBm
85