MEMS optical switch is a micro-optical switch that made of the semiconductor material, which is generally used as movable micro-mirrors that can deflect optical signals from input to output fibers. It embraces the advantages as compact, lightweight and easy to expand. Besides, it shares the merits of both the mechanical optical switch and wave guide optical switch. Since EMES combines the electrical, mechanical and optical integration as a whole, it can apparently transmit different rates and different business services. MEMS switches feature good scalability. Two-dimensional arrays with size 32×32 are already available and can be used as basic building blocks, in single-stage architecture, to scale up to 256 ports.