Asymptotic vector modes of inhomogeneous circular waveguides


  • Masahiro Hashimoto


An asymptotic theory is developed for vector modes of inhomogeneous circular waveguides, by means of which closed form expressions for the propagation characteristics of modes can be obtained. Basically, the theory is an extension of WKB's asymptotic theory based on scalar wave or geometric optical considerations to the coupled equations describing the basic properties of vector waves, and, therefore, the leading terms are the well-known lowest-order WKB solutions. The major part of the paper is offered on the theoretical foundations of the method. However, the formulas derived here are shown to be applicable for general classes of refractive index profile.