Demand for fast dynamic reconfiguration has increased since dynamic reconfiguration can accelerate the performance of implementation circuits on its programmable gate array. Such dynamic reconfiguration requires two important features: fast reconfiguration and numerous contexts. However, fast reconfigurations and numerous contexts share a trade-off relation on current VLSls. Therefore, optically reconfigurable gate arrays (ORGAs) have been developed to resolve this dilemma. ORGAs can realize a large virtual gate count that is much larger than those of current VLSI chips by exploiting the large storage capacity of a holographic memory. Also, ORGAs can realize fast reconfiguration through use of large bandwidth optical connections between a holographic memory and a programmable gate array VLSI. This paper presents the world's first demonstration of an ORGA with micro electro mechanical system's (MEMS) holographic memory.