The traditional methods for the characterization of ray trajectories i
n nonhomogeneous media are based on the Eikonal equation valid in the
region of geometrical optics. To apply Eikonal theory to fiber optics
requires a fairly extensive use of vector calculus and geometry. Alter
natively, through a simple correspondence rule, and a few intuitive gu
idelines for relating ray's to waves, an equivalent set of trajectory
equations can be obtained. This approach results in the Eikonal equati
ons for the space evolution of optical fiber rays which are expressed
in terms of the mode analysis invariants, azimuthal mode number, and o
ptical waveguide propagation phase constant.