Low-cross-talk 2 × 2optical switch

An electro-optical 2 × 2 switch for fiber-optic applications has been developed. Optical cross talk is reduced significantly by inserting two 2 × 1 switches in each optical path. A compact structure is used to contain the four 2 × 1’s that are required. We observed −27-dB cross talk and 2.5-dB insertion loss in both switching states. The device is controlled by a 5-V twisted-nematic liquid-crystal cell. Multimode, unpolarized light is switched.