As we know that a lot of transceiver type and distance support, each transceiver have own Power
Budget. Power Budget is mean the capability of the transceiver to handle optical loss. Power Budget
formula is same with Optical Loss Formula:
Power Budget = Transmit Power (dBm) - Receive (dBm)
Transceiver Optical Information
You can ask your transceiver vendor to get transmit and receive value of the transceiver (you can
browse on our Product Page to see our transceiver information).
Lets see the example below:
SFP+ 10G 40KM (QT-SFP+-ER)
|Part Number||Wavelength (nm)||TX Power (dBm)||RX Sens (dBm)||Distance|
|QT-SFP+-ER||1550||-2 ~ 4||-15,8||40KM|
TX Power = -2 ~ 4 dBm, we can see the TX Power is not have exact value, so for the safe we can use
middle value, in this case the middle value is 1 dBm
RX Sens = -15,8 dBm
Power Budget = 1 dBm - (-15,8 dBm)
Power Budget = 16 dBm
Power Budget Purpose
We need power budget data to compare with optical cable loss that we will use, so we can sure that we choose the correct transceiver for our need.
You can check this document to know about optical cable loss.