USE OF FEEDBACK IN OPTICAL INFORMATION-PROCESSING - REVIEW

The use of feedback techniques in optical information processing systems is growing rapidly. This review describes methods by which feedback has been produced, and discusses their applications to processing problems. The methods are classified according to the coherence length of the light source used, ranging from long (single axial mode lasers) through medium (multimode lasers) to short (incoherent light sources). Particular attention is paid to their potential for complex feedback, and for nonlinear and space-variant processing. The temporal characteristics of the systems and the means by which gain can be introduced into the feedback loop are considered. A current bibliography is given. © 1979 Springer-Verlag.