Estimation of power loss spectra in slightly flattened distorted Bragg fiber waveguide

Abstract

Dispersion characteristic and fiber loss spectra of a Bragg fiber waveguide having slightly flattened distortion are estimated for sensing applications. The characteristic and optical power loss equations of waveguide are obtained by matching the fields at various boundaries under quarter wave stack conditions. It is found that the optimum power loss is inversely proportional to the ninth power of distortion coefficient. The obtained results show that optimum fiber loss decreases with decrease of refractive index of cladding layer 'b' (low refractive index layer) and increase of refractive index of cladding layer 'a' (high refractive index layer). Also, fiber losses are estimated with increase of the high and low refractive index cladding layer losses. This loss spectrum of fiber can be considered as sensing signal. Since obtained fiber losses in distorted Bragg fiber are higher than standard Bragg fiber therefore, the sensitivity of proposed structure is higher than the standard Bragg fiber. Also, the sensitivity increases with the increase of refractive index of core medium. These results would be helpful to design a novel highly sensitive sensor based on hollow core distorted Bragg fiber. © 2020 Elsevier GmbH