Hello Aasif Bashir Dar. Good Evening Greetings from my side.
I checked the images you have shared. One thing stuck my mind about the waveforms displayed in the images that it may be because of either the dispersion down the feeder fiber link or the attenuation caused along the fiber channel. The third snapshot you have shared is very much distorted and it gives me an impression that it is because of the attenuation factor that your symbols are lost. Also check the power levels it goes down from 1m to 20 u.
Regards
Atul Sharma