We have demonstrated a tapped delay line microwave filter based on the use of high dispersion fiber as the tunable time delay. This system offers advantages of high bandwidth and tunability over current methods of time delay filtering.

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A parallel optical technique for use in the adaptive processing of radar signals is described. We have demonstrated such a technique in an acousto-optic adaptive signal processing system designed to null the jamming of radar signals. This system features a time integrating correlator using a new type of photorefractive spatial light modulator exhibiting high levels of contrast, resolution, uniformity and sensitivity. Using this system we have demonstrated nulling of both narrow and wide band RF signals. The operation of the photorefractive integrating device, its performance and that of the overall system are discussed.

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Neural networks can be applied to the problem of extracting multipath delay information from the correlation of two signals. The ability of a feedforward neural network to learn the correct delay vector response is demonstrated using both broadband and narrowband correlation data. A irained neural network can be combined with a traditional adaptive algorithm for systems applications such as adaptive interference cancellation. In many cases, the network improves overall system performance by providing a nearly optimal starting point. The use of such an approach in an existing optical processing architecture is discussed.