Abstract

There has been an increasing awareness in the recent literature that an understanding of the propagation characteristics of optical fibers is enhanced by the ray-optieal treatment of guided modes. Such phenomena as mode trapping or energy leakage for modes with high azimuthal field variation are elucidated, both qualitatively and quantitatively, by a ray-optical model that incorporates phenomena of total reflection at the core-surround interface. Also, the dispersion characteristics of graded-index fibers are studied advantageously by use of rays. In contrast to modal fields, which describe propagation on a "global” scale (a modal field has an unchanged profile in any cross section along the fiber), ray-optical fields describe propagation on a "local" scale in terms of local homogeneous plane waves (LHPW).

© 1975 Optical Society of America