Longitudinal Propogation Factor and Phase Velocity Calculator
This CalcTown Calculator calculates the longitudinal propogation factor and phase velocity of an EM wave, which is propagating through an optical fibre.
*Please note that phase velocity can exceed the speed of light in vacuum, but it does not violate the special theory of relativity.
θi is the angle the ray makes with the fiber axis, before entering the fiber,
k0 is the wavenumber of the EM wave in vacuum,
n is the refractive index along the central axis of the fiber,
vg is the group velocity of the EM wave.
and frequency is related to k0 by the equation c=2πf/k0