An electromagnetic Waveguide (a) that consists solely of Dielectric materials, (b) in which the dielectric propagation medium has a rectangular cross section, (c) that has a width, thickness, and refractive indices that determine the operating Wavelength and the Modes the guide will support beyond the equilibrium length, (d) that may be cladded, protected, distributed, and electronically controllable, and (e) that may be used in various applications, such as in integrated optical circuits (IOCs) in which their shape is geometrically more convenient than the optical fibers that are circular in cross section, that are used in Fiber optic Cables for long-distance transmission.

Note: Their principle of operation is the SAME as that for optical fibers that are circular in cross section.