High-speed infrared phase modulators using short helical pitch ferroelectric liquid crystals

A fast phase modulator based on ferroelectric liquid crystal (FLC) is demonstrated and its performances characterized. For uniform alignment and pure phase modulation, we propose a new FLC device configuration using short helical pitch material and homeotropic alignment structure. This device is driven by periodic in-plane electrode stripes implemented on the surface of both cell substrates. As a result, we have obtained large phase modulation (> 2pi at lambda=1.55 microm) and fast response (< 200 microsec).