Mems Micro-deformable Mirror System-level Modeling

Micro deformable mirror fabricated by MEMS technologies is one of the core components of the micro-mechanical adaptive optics system which is widely implemented in many fields such as telescope systems, laser beam weapons, medical high-resolution imaging systems and laser communication systems. In order to reduce the cost and shorten the design cycle, accurate and efficient system level modeling of micro deformable mirror involving optical phase modulation and mechanical and electrostatic coupling would invariably be needed.In the thesis, system level modeling methodology is presented for rapid modeling and simulation of micro deformable mirror. Based on the method, the system level model of the micro deformable mirror is established and simulated. The main contents of this thesis are as following:Firstly, The modeling methodology of mechanical and electrostatic behavior of the micro deformable mirror is presented and the models are established accordingly. Based on Multi-Port-Element Network(MuPEN) method, the mechanical model of the spring beam and the rigid plate mass is established according to law of energy conservation, while the mechanical and electrostatic coupling model of electrostatic gap is established based on mechanical and electrostatic energy transition principle. Meanwhile, all models are coded in analog hardware description language (MAST). Furthermore, the accuracy of models is verified by comparison with finite element analysis(FEA) and the results prove that the models have near FEA accuracy.Secondly, The modeling methodology of optical behavior of the micro deformable mirror is investigated and the models are established as a result. The description of optical signal is presented and the behavior model of the optical functional components such as planar reflection mirror and thin lens are established using matrix optics and Gaussian beam theory. The models are coded in analog hardware description language(MAST) and are simulated in MuPEN. In addition, the evaluation parameters of the optical quality for the micro deformable mirror arraysincluding the Strehl ratio and fitting error are analyzed. Then, MuPEN models for optical quality evaluation are established and simulation is implemented to analyze the effect of the parameters of mirror arrays on optical quality.Finally, system-level model of micro deformable mirror is established and both mechanical and electrostatic coupling simulation and optical phase modulation simulation are implemented in MuPEN. The resonance frequency, the response time and the pull-in voltage of the micro deformable mirror are ascertained through different simulations and the simulation results show that the micro deformable mirror we designed can satisfy the requirements of adaptive optics system. Moreover, the optical phase modulation behavior model of micro deformable mirror arrays is established for the first time. Then the simulation is implemented and the wavefront after phase modulation is reconstructed together with the analysis of relative error. Simulation results indicate that rapid modeling and simulation of micro deformable mirror can be accomplished in this way which will benefit the design and optimization of micro deformable mirror arrays.