Hi there!

This time, I will share with you a question about the Q value and the BER explanation.

Problem Description 

A customer request details about recommended Q value and BER for the performance of U3N401 boards.

Analysis Process

The Q value and BERhave a one-to-one mapping. A smaller per-FEC BER indicates a larger Q value and better link performance. You can check the relationship below:

But we can not give the exact Q range to the customer.  Only the criterion is that the service should not have bit error.

we can consider the alarm threshold depending on the FEC type.

For example, the following information:

FEC_BEF_CORER_FLOAT indicates the BER before FEC .

Such as  the belowU3N401 board, the “Current Pre-FEC BER” value would be 5.870e-8  .

Solution 

The recommendations are as follows:

For more information, please visit alopez's share:

OSNR, BER, and Q value

That's all, I welcome everyone to leave a message and exchange in the comment area!

Thank you！