Complex modes in negative-refractive-index fibers

Abstract

In this paper, we focus on the properties of the complex modes in negative-refractive-index fibers. The characteristic equations for TE and TM modes in negative-refractive-index fibers are given. These solutions, termed complex surface waves, form another set of proper modes. We show that dispersion diagram for both TE and TM modes in negative-refractive-index fibers, including evanescent, ordinary, and complex surface modes. It is found that the complex surface modes have high cutoff frequencies which means they exist only when the frequency is lower than their respective cutoff frequencies. After a careful examination, we found that the total power flow turns out to be simply zero.