Two-dimensional (2D) micromirror with enhanced tilting angle using active control methods

Electrostatically actuated torsional micromirror fabricated using MicroElectroMechanical Systems (MEMS) technology is a fundamental building block for many optical network applications, such as optical wavelength-selective switch, configurable optical add-drop multiplexers and optical cross-connects. A two-dimensional (2D) micro-mirror functioning with a flexible secondary tilting offers tremendous value for the network designers. Commonly, electrostatic MEMS micromirrors have been designed with a gimbal surrounding the mirror plate and four square electrodes underneath. The main disadvantage of this type of design is the X-Y tilts are extensively coupled, which makes design of a control system difficult. In this work, design and control of an electrostatically actuated 2D MEMS micromirror has been reported. Triangular shaped electrodes have been used to achieve relative decoupling and a multi-loop proportional, integral and derivative (PID) controller is designed. The simulation results show that decoupling for small tilting angles has been achieved and that the controller can achieve a larger controllable tilting angle than the pull-in angle resulting in significantly enhanced device performance and functionality.