Abstract
Three-dimensional-ray trajectories in an optical fiber are derived using a simple correspondence principle. The ray trajectories are linked to the mode number of the exact waveguide solutions. The analysis and simulations presented are in terms of dimensionless parameters needed to characterize the optical fiber. Specifically, this includes the V-parameter, the core index of refraction, and the numerical aperture. The curves for allowed radial and azimuthal mode numbers are presented in terms of dimensions that are normalized by the core radius. The approach is extensible to graded-index fibers.