Numerical analysis of metal-clad pentagonal waveguides

ABSTRACT Using the weak guidance approximation and the point matching technique, a thorough analysis has been carried out of the propagation characteristics of a dielectric pentagonalwaveguide cladded by a perfectly conducting substance. Metal-clad waveguides have been drawing the attention of many workers as they can be designedto act as efficient mode analyzer in integrated optical circuits, e.g. directional couplers etc.1'2 Also, metalliccoating in such guides is used in interfacing of optical components with electrical and electronic systems,connecting optical components of different dielectric constants etc.Guides with triangular cross-sections have been studied.35 A special example of a fiber with a non-circular cross-section is the waveguide where this cross-section is a regular polygon. Owing to the presence of sharp corners, it is very difficult to present an exact numerical analysis for such guides. The present paper reports a numerical study of the characteristics of a guide with a regular pentagonal core