hi ranjeet sir..m thankful to u for ur kind reply n time..
actually m new to the optiwave tool and i thought it was some parameter i was not setting while simulation.. i thought it is compulsory fr good results n thats why i asked abt it.
bt it s ok i hv used splitter nw and thanx to all ur suggestions..they helped a lot for understanding the basic diffrnce between the two..thanx agn