ABSTRACT
This chapter provides the attenuation and distortion of pulses which propagate in monomode and multimode optical fibers. It outlines the characteristics of optical fibers that influence the propagation of light pulses. A thorough understanding of optical fiber propagation requires an appreciation of mode theory. Based on James Clerk Maxwell's equations, this approach permits a comprehensive vision of propagation in step-index fibers. The widespread use of optical fibers is due mainly to progress that has been made in bringing fiber attenuation from hundreds of decibels per kilometer to a decibel or less per kilometer. The coupling of energy between incoherent light sources and monomode fibers is very poor because the core of a monomode fiber has a very small diameter. Designing optimal monomode systems involves basically the expression for the first order dispersion coefficient. According to the laws of geometric optics, a ray propagating in a homogeneous medium travels in a straight line.
