Estimate RMS pulse broadening per km due to intermodal dispersion for multimode step index fiber where length of fiber is 4 km and pulse broadening per km is 80.6 ns.

Correct Answer: 20.15ns/km
The RMS pulse broadening per km due to intermodal dispersion for multimode step index fiber is given by (σs(1 km)/L = 80.6/4 = 20.15 Where L = length of fiber σs = pulse broadening.