The current major limiting factor in digital optical computing is the absence of a fast, efficient, cascadable optical switch. Material and processing approaches to optical switch construction are not limited to the well known semiconductors and fabrication methods of electronics. A facility to evaluate candidate devices has been constructed. Multiline and tunable femtosecond and picosecond laser systems, as well as frequency mixing systems, are used as light sources. The facility has at least picosecond source capability from 200 nm to 2 μm. The switch transfer function is evaluated in a pump-probe system with femtosecond and picosecond autocorrelators to measure temporal properties, an optical multichannel analyzer to measure spectral properties, a CCD or pyroelectric camera system to measure mode modification, and a multi-detector system to measure switching energy and insertion loss both in absorption and in reflection. The switch or switching array under test is mounted in a 6 axis micropositioner system with a 0 - 20 goniometer, x, y, and z translators, and a tilt goniometer. The system's design, as well as initial measurements of nonlinear interface optical switches based on photorefractive thin films are presented.