STUDY OF A METAL-CLAD OPTICAL WAVE-GUIDE WITH A PERIODICALLY VARYING CORE RADIUS

A theoretical analysis has been made for the propagation of electromag netic waves in an optical fiber having a conducting core-cladding boun dary with the core radius varying periodically along the propagation a xis. Using Maxwell's field equations, the characteristic eigenvalue eq uation has been derived for such a metal-clad fiber under the strong g uidance condition. One finds that the z-component of the propagation v ector beta depends on the variable z, the axial coordinate. The modes, therefore, show a local behaviour. The variation of partial derivativ e beta/partial derivative z with the z coordinate has been computed fo r some low order modes.