In this paper, the electromagnetic scattering properties due to periodical configurations consisting of planar optical waveguides completely surrounded by a fluid media, in gaseous or liquid phase, are analyzed. In this new design, fluid separates the consecutive optical waveguides and it is also the common cover for all of them, thus significantly increasing the effect of the fluid on the evanescent field. This new configuration is designated as fluidic segmented optical waveguides. The theoretical algorithm was developed and recently updated by the authors, and it is based on the generalized scattering matrix concept, together with the generalized telegraphist equations formulism and modal matching technique. We present the first theoretical results concerning to these periodical structures with a fluidic common cover. To carry out the simulations, with the purpose to manufacture these devices in the future, glass and polymer were chosen as materials for the optical waveguides substrate and for enclosing the fluid as common cover medium, respectively. The spectral results obtained for the module and phase of the reflection and transmission coefficients have shown great sensitivity of the new proposal to the variations of the refractive index of the fluid, making it very attractive for the design of refractive index sensors and optical biosensors.
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