Calculating the EX 8200 series Switch Fiber-Optic Cable Power Budget
Calculate the link's power budget when planning fiber-optic cable layout and distances to ensure that fiber-optic connections have sufficient power for correct operation. The power budget is the maximum amount of power the link can transmit. When you calculate the power budget, 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 the worst-case levels.
To calculate the worst-case estimate for fiber-optic cable power budget (PB ) for the link:
- Determine values for the link's minimum transmitter
power (PT ) and
minimum receiver sensitivity (PR
). For example, here, (PT ) and (PR
) are measured in decibels, and decibels are
referred to one milliwatt (dBm).
PT = –15 dBm
PR = –28 dBm
Note: See the specifications for your transmitter and receiver to find the minimum transmitter power and minimum receiver sensitivity.
- Calculate the power budget (PB ) by subtracting (PR ) from (PT
–15 dBm – (–28 dBm) = 13 dBm