We present the design of a planar-integrated optoelectronic vector-matrix multiplier. The inherent

parallel-processing potential is fully exploited by optical implementation of multiplications and

summations. Planar integration makes the free-space optical system compatible with electronic

VLSI technologies. It is composed of phase-only diffractive optical elements, which implement lens

and multiple-beam-splitter functions. A demonstrator version of the optical system for a matrix of

size 10 3 10 was fabricated on quartz glass by means of multimask lithography and reactive ion etching.

It shows low cross talk and good uniformity of the signals.