Difference between input power (dBm) and Reference input power (dBm).

Dear friend!
The input power is the actual receive power of the optical interface, and the reference input power is a reference value. The reference input power is an ideal value. During optical power commissioning, the actual receive power of the optical interface must be as close as possible to the reference value.

If the value of the received power is equal to the reference value when all other parameters are normal, this is a perfect state.

When other parameters are normal, if the received power is greater than or equal to 4 dB, the transmission performance of the optical channel deteriorates (bit errors may occur). In this case, you need to commission the optical power again.

Thank you!