The specification of coherent optical data processor components on the basis of approximate analogs and the inability of the optical designer to relate actual performance requirements to lens ray tracing computations have often resulted in systems that are disappointing in their results. Designing and manufacturing such systems to desired performance standards require a knowledge of both the communications and practical optical engineering aspects of the problem. The manner in which real coherent optical systems can be designed and assessed is illustrated by two examples. Quantitative criteria have been developed that are analogous to, but that differ significantly from, those used for assessing the quality of incoherent optical imaging systems. The usual computational methods available to optical designers are easily adapted to the evaluation of these criteria. The user can apply them to set specifications that are quantitatively related to the level at which his systems will perform.
Abe Offner, "Design and Specification Criteria for Optical Data Processors," Appl. Opt. 7, 2285-2288 (1968)