Fabrication of a sidewall reflective optical switch by using FIB etching

As a key device of micro-optical electromechanical system technology, silicon-based MEMS optical switches have become a frontier research hotspot in the current world of science and technology development. The mechanical analysis and structural design of sidewall reflective optical switch is straightforward. However the high roughness of the sidewall limits the application of MEMS sidewall reflective optical switches. This study proposes an effective method to process the sidewall surface by using focused ion beam (FIB) etching. The effect of FIB etching on an Si sidewall surface was experimentally investigated. The surface roughness of the sidewall mirror was improved from 126 nm to 5 nm. The improvement in FIB etching for a MEMS sidewall reflective optical switch was demonstrated. The output power of the MEMS sidewall reflective optical switch has been increased by more than 300%. We believe this work is significant for high precision processing for sidewall reflective optical switches, promoting the application in the research fields of optical engineering, microfluidics, instrumentation and so forth.