Liquid-crystal tunable plasmonic stripe directional coupler switches

In this work we design and theoretically investigate optical switches based on long-range plasmonic directional couplers, which are controlled via the electro-optic effect of nematic liquid crystal layers. Employed numerical tools include a fully-anisotropic finite-element-method, the eigenmode-expansion method, and a rigorous finite-element based calculation of the liquid-crystal molecular reorientation. Both horizontal and vertical configurations are assessed, providing a comparison in terms of key-performance characteristics, such as coupling length, switching voltage, insertion losses, and crosstalk. These tunable plasmonic devices are envisaged as ultra-low power consumption switching elements in integrated platforms for optical inter-chip interconnects. © 2013 SPIE.