Electrooptic 4x4 matrix switch for multimode fiber-optic systems

A new fiber-optic switch for multimode fiber networks has been developed. This voltage-controlled device can switch light from any of four input fibers to any of four output fibers. Four input/output connections are made simultaneously, and the matrix has twenty-four such states. No moving parts are needed because the switching is accomplished with an electrooptic effect in nematic liquid crystals. Low levels of optical crosstalk, ~40 dB below the output signal level, are obtained with a unique two-stage architecture. The design, construction, and observed performance of this optical switch are described.