This work was supported in part by the National Science Foundation and Tektronix, Inc
Electromagnetic waves -- Scattering, Wave guides
The basic electromagnetic properties of tapered graded index fibers are equivalent to the properties of a class of concave metallic waveguides. Although useful in their own right, such metal waveguides also provide a straightforward and inexpensive means for studying the characteristics of more complicated tapered media.
Lee W. Casperson, Bahram Zandi. Metal waveguide modeling of tapered quadratic index media. Applied Optics, Volume 25, Number 23 (December 1986), pp. 4417-4420.