Optical dispersion curves of a light waveguide with a guiding region cross-section resembling a double convex lens

This paper reports the study of the dispersion characteristics of a new lig ht waveguide having a cross-sectional shape resembling that of a double con vex lens. This shape may be considered as a distortion of elliptical shape. If the elliptical waveguide is given a transverse compression at the extre mities of the major axis, the distortion may be represented by a double con vex lens. Using Goell's point matching method under the weak guidance condi tion, the modal characteristic equation has been obtained. From the charact eristic equation we get the dispersion curves for some low order modes. It is found that these curves are of the expected shapes and are crowded near the cut off V-values.