Analysis of a phase shifter based on a slot polymeric waveguide with liquid crystal cladding

We numerically investigated a phase shifter based on a polymeric platform by using two different approaches. The device consists of a polymeric slot waveguide covered with an organic liquid crystal cladding, which is a promising configuration for the implementation of polymeric waveguide systems for computation, communication and sensing. Two different nematic liquid crystals have been considered, E7 and 5CB. At first, we have indirectly computed the phase shift through a combination of 2D Finite Element Method with index ellipsoid theory. Then, we have investigated the signal propagation by means of 3D Finite Difference Time Domain Method, which allowed to obtain also the intrinsic propagation loss of the structure and the materials. Although each approach introduces specific approximations and requires different resources, both give similar results and confirm the excellent quality of the device, namely low propagation losses and relevant phase shifting capability.