Hi esakkimuthu,
As I mentioned before about your question, I have never had this experience with OptiFDTD by this moment to give you a proper and useful advice. Beside that (I just noticed it), Damian clearly states that “Right now that is not directly possible. OptiFDTD is the only package that cannot be directly incorporated into OptiSystem”. Let’s see if more experienced with OptiFDTD members can advise you something…