Integrated electro-optical switch based on nematic liquid crystal

Abstract

An integrated electro-optical switch based on a planar nematic liquid crystal waveguide has been realized and tested. To achieve this goal, we fabricated and measured a number of step-index waveguides, using RF sputtering and sol-gel deposition techniques. A summary of their characteristics is presented. The design of electro-optical switch is reported, together with the analysis of the problems met in order to optimize the manufacturing process. Finally, we present the experimental results obtained with a three-stages device, having as middle stage a thin nematic LC film and two glass waveguides as other stages. The electro-optical behavior and the response times have been studied for different configurations. The experimental findings show that an additional bias voltage can improve both the transmittivity and the response time of the device, leading to very promising results in the frame of new integrated electro-optical switches.