Hi,
Thanks for your reply. Yes the major cause is dispersion. I somehow made the DCF while reading some research papers about commercially available DCFs. After putting the parameters somehow setup works. But when I disable the DCF again constellation becomes worst. But still I am unable to understand either these parameters can be used in PON configurations.
What are your thoughts that the DCF parameters are separate for PON configurations and separate for all other configurations. Or in short there is separate DCF for PON and separate DCF for other setups.
Regards,
Umar