Finite curvature and corrugations in dielectric ridge waveguides

The authors present a technique based on the concept of local modes that is capable of handling finite, tight bends in open dielectric waveguides of the LSE-mode or LSM-mode type, together with step discontinuities along the arc. By analytical manipulation of the continuum, the approach results in a small system of coupled integrodifferential equations, one for each discrete propagating mode. The latter system is solved analytically by means of an iterative approach to the point where it can be implemented on a desktop computer. The method was applied to the curved, corrugated, dielectric ridge waveguide, yielding numerical results in general agreement with published experimental points. The technique is equally applicable to other curved open transmission media in the microwave, millimetric, and integrated optics ranges