“…The study of circular fibers has been important not only to improve their propagation characteristics but also to motivate technological developments of associated optoelectronic components. It is also known that a waveguide with a non circular cross-section is special interest due to its possible use in integrated optics (Kawakami and Nishida, 1974;Lewin, 1974;Misra et al, 1995;Matsuhara et al, 1988;Gu et al, 1989;Singh et al, 2000Singh et al, , 2001. Analytical studies of such non-circular fibers, being difficult, are rather rare.…”