Abstract

Electrooptic switching in ferroelectric liquid crystals (FLCs) produces large changes in their refractive index. This change, typically 0.15, is useful for optical switches that operate via total internal reflection (TIR) in contrast to most other electrooptic devices, both solid state and liquid crystal, that use variable retardance. We present experimental observations on both bulk optic and waveguide FLC devices that utilize TIR. Our devices are typically two state having one state where the incident light is below the critical angle and another state where the critical angle is decreased so that the same incident light is beyond critical. Application of 10 V/μm across an FLC film can accomplish switching between these two states in tens of microseconds. The advantages of the bulk optic device include its very high off-state extinction (~10⁶) and the independence of its on-state transmittance on wavelength. The advantages of the wavelength device include the very short interaction length it requires enabling its integration into very dense optical switching arrays.

© 1988 Optical Society of America