Using the epitaxy-on electronics (EoE) process, self-electrooptic effect devices (SEED's) have been monolithically integrated with VLSI GaAs electronics., The EoE approach provides both depletion-mode and enhancement-mode MESFET's for large-scale, high-density optoelectronic circuits, The performance of SEED's grown by molecular beam epitaxy at a reduced temperature compatible with the EoE process is shown to be robust, and modulators with contrast ratios of 2.3:1 at 7.5-V bias have been integrated on commercially processed VLSI GaAs circuits, The EoE-SEED process offers potential improvements over the FET-SEED process, facilitating the applications of SEED's in free-space optical switching and computing.