hi sahil singh,
150 km fiber lfor data rate 20 gbps and compare results at different data rate like 5 gbps, 10 gbps ;;;; is quit easy task
first you need some dispersion compensation method , e.g break 150 length span in two i.e 75 and 75.
no w in each 75km use 60 km single mode fiber ans 15 km ad dispersion compensation fiber.
please also increse upto 5dbm
with regards