Generalized linear processors for coherent optical computers

Generalized optical processors are examined from the point-of-view of developing a systematic method for determining which linear processing operations may be performed in a coherent optical system. In this paper a procedure is presented for examining a general n-plane processor and expressing the resulting system in terms of a conventional linear processing model. The generalized kernel of the resulting integral equation is used to describe currently well understood coherent linear processors as simple examples of a more general n-plane processor. A 2-plane processor is shown to correspond to the Fourier transform operation with a simple lens, and the 3-plane processor is associated with convolution or correlation. The kernel of a 4-plane system is shown to resemble the ambiguity function, and to represent an oblique to rectangular plane inverter, when an appropriate assumption is made about the complex amplitude-transmittance function of one optical plane. The more general n-plane kernels have integral representations for which simple physical realizations remain to be developed.