Advanced Digital Optical Communications, 2nd Edition

2

Optical Fibers

2.1 Overview

Planar optical waveguides comprise a guiding region and a slab embedded between a substrate and a superstrate having identical or different refractive indices. The lightwaves are confined by the boundary, and guided under the condition that oscillation is achieved, hence the wave exhibits evanescent penetration in the cladding region. The number of oscillating solutions that satisfy the boundary constraints is the number of modes which can be guided. The guiding of lightwaves in an optical fiber is similar to that of the planar waveguide except that lightwaves are guided through a circular core embedded in a circular cladding layer.

Within the context of this book, optical fibers are treated as circular optical ...