High-optical-isolation low-loss moderate-switching-speed nematic liquid-crystal optical switch

A bulk polarization-rotation-based 1 × 2 optical switch is demonstrated by use of a birefringent-mode parallel-rub nematic liquid-crystal cell and a calcite Thompson-prism polarizing beam splitter. With 633-nm linearly polarized light the switch output ports exhibit a >36-dB optical isolation with less than −0.75 dB of optical insertion loss. A <1.5-ms switching speed is demonstrated for a cascade cell optical arrangement by means of the transient nematic effect with >30 dB of optical isolation and −1.45 dB of optical loss.