On the propagation and sensitivity of optical fiber structure with twisted clad DB interface under slow-wave approximation

The paper deals with the study of slow-wave propagation through an optical fiber having linear, homogeneous and isotropic dielectric core with a newly proposed helical DB interface at the core-clad boundary. The dispersion relation is deduced, and the flux density patterns are studied considering a few low-order hybrid modes under slow-wave approximation. Furthermore, the sensitivity of fiber structure is investigated in terms of variations in the evanescent wave enhancement factor due to the pitch angle of twists and the thickness of clad section. It has been found that the field enhancement factor can be tuned by properly adjusting the pitch, and also, the thickness of clad section as the evanescent waves in this region get greatly affected due to the varying pitch.