FERROELECTRIC LIQUID-CRYSTAL WAVE-GUIDE MODULATION BASED ON A SWITCHABLE UNIAXIAL-UNIAXIAL INTERFACE

Liquid crystals have effective electro-optic coefficients that are ord ers of magnitude larger than other integrated optical materials such a s lithium niobate. However, previous studies of liquid-crystal wavegui des have mainly focused on nematic liquid crystals, which exhibit impr actically large scattering losses as waveguides. Studies of smectic li quid crystals and liquid crystals under strong confinement suggest the losses in these materials may be more manageable. In this study, the possibility of using ferroelectric Liquid crystals in active waveguide modulators is explored through the analysis of several modulator conf igurations: a cutoff modulator, a deflection modulator, and an input c oupler. As a way to study these structures, a mode-matching technique was developed to analyze the effects of a discontinuity in a uniaxial slab waveguide whose optic axis is in the plane of the waveguide. The results from the mode-matching technique were compared with those from simple bulk models. The analysis shows that ferroelectric liquid-crys tal modulators have many desirable performance characteristics and cou ld form the basis for practical waveguide modulators. (C) 1996 Optical Society of America