Table 33: Estimated Values For Factors Causing Link Loss - Juniper QFX5100 Hardware Manual

Table 33: Estimated Values for Factors Causing Link Loss

Link-Loss Factor
Higher-order mode losses
Modal and chromatic
dispersion
Connector
Splice
Fiber attenuation
Clock Recovery Module
(CRM)
Copyright © 2017, Juniper Networks, Inc.
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
a QFX Series Device" 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 33 on page 87
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
Chapter 7: Transceiver and Cable Specifications
"Calculating the Fiber-Optic Cable Power Budget for
86.
(here, the link is 2 km long and multimode, and
Sample Link Loss (LL) Calculation Values
0.5 dBm
0 dBm
0 dBm
0 dBm
This example assumes five connectors. Loss for five
connectors: 5 (0.5 dBm) = 2.5 dBm.
This example assumes two 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: 2 km (1 dBm/km) = 2 dBm.
This example assumes the link is 2 km long. Fiber
attenuation for 2 km: 2 km (0.5 dBm/km) = 1 dBm.
1 dBm
):
B
) for the link:
M
87