A numerical study of optical switches and modulators based on ferroelectric liquid crystals

Optical switches and modulators based on ferroelectric liquid crystal (LC) cladding layers are numerically analysed. The switches follow a directional coupler design with the LC layer placed between two waveguides, and the level of coupling between them is directly controlled by the LC material state. Similarly, the modulators use the LC as a switchable cladding layer. Light propagation is tackled using an appropriate beam propagation method suitable for anisotropic materials, retaining the pertinent coupling between the field components. The variation of the LC director orientation through the cladding layer is carefully considered by examining profiles which are typically anticipated. Calculations demonstrate a performance which is compatible with the needs of a low-cost class of devices for optical communications.