EFFECTS ON THE ENERGY FLUX DENSITY DUE TO PITCH IN TWISTED CLAD OPTICAL FIBERS

The paper deals with the propagation of electromagnetic waves through twisted clad dielectric optical flbers. The structure of these flbers is analogous to travelling wave tubes used in microwave devices, and the usefulness would be in the areas of optical sensing. This is because the twists in flber would be afiected due to the imposed stress and/or strain, leaving thereby the possibility to alter the propagation characteristics. A rigorous analytical investigation has been carried out with the emphasis on the energy ∞ux density patterns due to the difierent propagating modes in the flber. The dispersion relations of the system are deduced and the energy ∞ux densities are evaluated under difierent pitch angles of twist. The efiect due to conducting helix pitch on the electromagnetic wave propagation is emphasized.