Abstract Existing 3D MEMS-based optical switches offer good optical properties (low insertion loss, low crosstalk), high reliability and low power consumption. These switches utilize highly reflective micro-mirrors to manipulate an optical signal inside the switch directly without any conversions. They are used to build dynamically reconfigurable, highly-scalable physical optical network layer. As indicated by the simulation results of this paper, many of existing micro-mirror designs do not have their dynamic characteristics well optimized and this limits the switching speed of the optical switch. In a 3DMEMS switch, the coupling between the mechanical structure (micro-mirror) and electrostatic field (electrodes) results in dynamic coupled rotation of the micro-mirror about its axes, known as the cross-axis coupling effect. The coupling nature of micro-mirror rotation makes its control difficult. In this paper,we present the simulation case studies and a simple optimization technique leading to decoupled rotation of the micro-mirror about two perpendicular axes. This helps to reduce the switching time of the switch while keeping the same manufacturing process and only minimal design changes.