Shock-Resistant Design for MEMS Optical Switch Based on Displacement-Limited Structure

Microelectromechanical systems (MEMS) optical switch, notable for its compact dimension and ease of integration, has been widely applied in military and aerospace fields. However, when facing the high value impact overloads and shocking environment, the structural failure may occur in the MEMS optical switch, causing the functional damage in the whole system. This paper focuses on the methodology of shock-resistant design for multi-body coupling MEMS optical switch basing on displacement-limited dynamics and novel fabrication process. A back-support structure and glass cap work together to protect the movable microstructure against out-of-plane displacement. A double-sided deep reactive ion etching process was used to fabricate the MEMS optical switch on a silicon-on-insulator substrate. A model was constructed based on displacement-limited dynamics to explain the protection mechanism under high overloads. Experimental results indicated that the MEMS optical switch survived overloads as high as 25,000 g with an impulse of 105 μs, which far surpass the shock resistances of existing designs. This study is expected to promote the application of functional MEMS optical switch in high shocking environments.