Hi Areej,
You can do Report–>Grid and select the OSNR from visualizer you want and BER from your BER analyzer.
You will do right-click on the block of BER. You will see a component view link after that. And then, you will see the value of BER.
If you are designing WDM network, you can use WDM analyzer which provides the value of BER.
The useful equation which relates these two values is lg(BER)=10.7-1.45*(OSNR). Any software (even excel) can be used for plotting this simple graph.
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