Sir Rk Sethi Thanks alot for such Explanatory Answer.
Sir i have optimized my system on 2dB Extinction Ratio and the system is showing good results with good eye opening.
As you said that the typical value is between 20—40dB. But in my case i am using 2dB. Is it Practically possible? Because theoretically it is showing good results.
Hoping for your kind reply
Best Regards