Which pulse will reach reiever first is transmitted via pure silica?

Question

Consider a pulse emitted at two discrete optical wavelengths (w1=500nm, w2=650nm ) and transmitted in pure silica. Will the pulse at the longer or shorter wavelength reach the receiver first? Which wavelength can travel longer distance without amplification?

Answer 1

Look up work on dispersion of light in SiO2.
If the frequencies are near a resonance severe changes in the speed of the light pulses can occur.