Dear Nabadh,
The issue could be related to the data rate that you are using. You know that the LED is a noncoherent light source and has limited modulation bandwidth. Try to lower the rate and check the performance.
You may send me your file as a zip file to ahmad.atieh@optiwave.com and I’ll check it out and provide feedback. Unfortunately, you can’t upload OptiSystem project on the forum.
Regards,
Ahmad