Hello Nabih,
According to your last question about the usage of sweep function, did you try to take a look at some of the tutorials? Lesson 4, for example, describes how to combine the results from the BER/Eye Analyzer with the signal input power using parameter sweeps. Here is the link for this lesson: http://staging.optiwave.com/forums/topic/parameter-sweeps-ber-x-input-power/.