This paper is concerned with the study of propagation in multimode fibers having nearly step index shape with elliptical symmetry. A method based on ray tracing and modal relations, previously adopted for evaluating the dispersion characteristics in circular fibers with different refractive-index distributions, has been applied with suitable modifications. Examples of dispersion curves are shown for different ellipticities, which do not exhibit substantial differences with respect to those relative to the circular case. The existence of “whispering” and “bouncing” modes is also pointed out: the number of the latter is more relevant the higher the ellipticity of the fiber. This fact can be interesting for coupling purposes.
© 1979 Optical Society of America
P. F. Checcacci, R. Falciai, and A. M. Scheggi, "Whispering and bouncing modes in elliptical optical fibers," J. Opt. Soc. Am. 69, 1255-1259 (1979)