A basic element for integrated electro-optical devices based on liquid crystal waveguides

Integrated optical devices based on liquid crystal's (LC) features have been generally discarded for a long period mainly due to very high scattering losses. However, in the 90's this situation is rapidly changing. A better understanding of the physical phenomena underlying the observed effects, the use of new materials with improved performances, the discovery of new electro-optical and nonlinear optical effects make the applications of LC in integrated optics more and more attractive. We present here some recently obtained results in this field. In particular, we have designed and realized an integrated device in a three-stage planar waveguide, having as middle stage a nematic liquid crystal (NLC) film. We studied the device performance in different geometries using TE polarized light. By a proper choice of the material parameters we measured time responses in the microsecond range. Our experimental results confirm the possibility of employing such a device working as an optical switch and/or beam deflector.