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.

Longitudinal Propogation Factor and Phase Velocity Calculator

Incident angle (θ_i)

degree

Frequency (f)

MHz

Refractive index along the central axis of the fiber (n)

Result

wavenumber

Longitudinal Propogation constant for Optical Fibre (β)

m-1

Phase Velocity

m/s

where

θ_i is the angle the ray makes with the fiber axis, before entering the fiber,

k₀is the wavenumber of the EM wave in vacuum,

n is the refractive index along the central axis of the fiber,

v_gis the group velocity of the EM wave.

and frequency is related to k₀by the equation c=2πf/k₀