A multimode step index fiber has source of RMS spectral width of 60nm and dispersion parameter for fiber is 150psnm-1km-1. Estimate rms pulse broadening due to material dispersion.

Correct Answer: 9.0ns km-1
The RMS pulse broadening per km due to material dispersion is given by σm(1 km) = σλLM = 60*1* 150pskm-1 = 9.0nskm-1 Where σλ = rms spectral width L = length of fiber M = dispersion parameter.