Multimode optical fiber has an optimum near parabolic graded-index profile. The source used is an LED having a spectral width of 25nm. The material dispersion parameter is 30 /( . ) ps km nm. The pulse spread due to waveguide dispersion in this fiber is much smaller than the pulse spread due to material dispersion. The optical fiber has a numerical aperture of 0.40 and a core axis refractive index of 1.48.

a. Estimate the total pulse spread per kilometer within the fiber.

b. Estimate the bandwidth-length product of the fiber.