Simulation and animation in optical fiber communication

Abstract

Students find certain concepts in fiber optic communication theory difficult to grasp. A classic example is electromagnetic mode theory in cylindrical coordinates. The solutions of the differential equation which describe the modes of the fiber are Bessel functions, with which most students are unfamiliar, and the vectorial nature of the analysis only complicates the situation. A second difficult concept is dispersion. The fact that different frequencies of light travel at different speeds in the fiber is not confusing. It is in the implications where the difficulty arises. Specifically, the concept of group velocity is physically counterintuitive, and an analysis of the pulse spreading that results because of dispersion often includes a-rigorous Fourier analysis. This paper describes how computer simulation and animation can provide a visual means of simplifying these concepts so that they are easier to understand.