Calculating The J-Ex8200 Switch Fiber-Optic Cable Power Margin - Dell PowerConnect J-EX8208 Hardware Manual

Related
Documentation

Calculating the J-EX8200 Switch Fiber-Optic Cable Power Margin

Table 39: Estimated Values for Factors Causing Link Loss
Link-Loss Factor
Higher-order mode losses (HOL)
Modal and chromatic dispersion
Calculate the power budget (
2.
–15 dBm – (–28 dBm) = 13 dBm
Calculating the J-EX8200 Switch Fiber-Optic Cable Power Margin on page 85
Optical Interface Support in J-EX8200 Switches on page 45
Understanding J-EX8200 Switch Fiber-Optic Cable Signal Loss, Attenuation, and
Dispersion on page 72
Calculate the link's power margin when planning fiber-optic cable layout and distances
to ensure that fiber-optic connections have sufficient signal power to overcome system
losses and still satisfy the minimum input requirements of the receiver for the required
performance level. The power margin (
attenuation or link loss (
LL
When you calculate the power margin, you use a worst-case analysis to provide a margin
of error, even though all the parts of an actual system do not operate at worst-case
levels. A power margin ( P
M
to operate the receiver and that it does not exceed the maximum receiver input power.
This means the link will work. A (
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 "Calculating the J-EX8200 Switch Fiber-Optic Cable
Power Budget" on page 84.
To calculate the worst-case estimate for the power margin (
Determine the maximum value for link loss (
1.
applicable link-loss factors—for example, use the sample values for various factors
as provided in Table 39 on page 85 (here, the link is 2 km long and multimode, and
the ( ) is 13 dBm):
P
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
P ) by subtracting (
B
P ) is the amount of power available after
M
) has been subtracted from the power budget (
) greater than zero indicates that the power budget is sufficient
) that is zero or negative indicates insufficient power
P
M
) by adding estimated values for
LL
Sample (LL) Calculation Values
Chapter 7: Planning Power Requirements
P ) from ( P ):
R T
).
P
B
P ) for the link:
M
0.5 dBm
0 dBm
0 dBm
0 dBm
85