Nonlinear optical propagation in dye-doped liquid crystal waveguides

We present an experimental study of light propagation in dye-doped liquid crystal planar waveguides. A special three-section guiding device has been designed and realized. Both TE and TM polarization of the input laser beam are considered. Homeotropic and planar alignment at the waveguide walls are employed as the liquid crystal film geometry. Above a power threshold, we observe nonlinear mode coupling mismatch between the waveguide sections and decreasing output power versus increasing input power. We compare the experimental observations with the numerical results obtained from a theoretical model of the device and find good agreement. The huge nonlinearity exhibited by liquid crystals is further enhanced by the presence of the dye dopant, making the realization of low-power all-optical integrated devices feasible and attractive.