Damian is right. You can apply sweeps for any parameter like input power, distance etc.
You can also do one thing, prepare one design (operating at 40 Gbps or you can go for WDM network if higher speed is required ) then apply sweeps to the two parameters : input power and distance.
for e.g. input power = -5, -3, -1, 0, 1, 3, 5 dBm
Distance = 50 Km x N spans (N = 1,2,3,4,5,6,7,8,9,10…..up to 100) , so total distance will be around 5000 km
Now simulate this design with three different modulation schemes : BPSK, QPSK and Duo Binary
I think, this will give sufficient no of results for your thesis or project submission. You can go for comparative analysis of all three modulation formats and come to know that QPSK is good.
You can refer one paper also which also give the same kind of comparison but with three different modulation formats. here is the link: