EXACT EIGENVALUE EQUATIONS OF MODES IN ELLIPTIC FIBERS OF STEP-INDEX PROFILE

The exact eigenvalue equations of modes in elliptical fibers of step-i ndex profile are not available in the literature. By using a rigorous method, an elliptical fiber mode of step-index profile is expressed in terms of the even and odd Mathieu wave functions of the first kind in its core and in terms of their decaying even and odd modes in its cla dding. Then, by matching the tangential components of the total electr omagnetic fields across the core-cladding boundary and using the ortho gonalities of the circumferential Mathieu functions, the eigenvalue eq uations are derived in closed forms. Results are shown for the propaga tion characteristics of some low orders of the elliptic modes.