Hi shahbaz
As far as sequence length is concernexd,you will see the change as longer seq. Length makes system more accurete as suggested in various post in forum archives.However just for knowlege could you please tell,have you tried to maje ber vs rx for file N.osd? Without any changes to file?
You can increase and decrease the length of fiber,no issues in that.effects is that you will get lesser rx power and more ber at longer distance.
I suggest you thst once you check the the N.osd and try to make ber vs rx.