Design and analysis of an intensity modulated micro-opto-electro-mechanical accelerometer based on nonuniform cantilever beam proof mass

Abstract

Micro-opto-electro-mechanical (MOEM) accelerometers using principle of optical coupling between two waveguide structures is proposed. It consists of an antiresonant reflecting optical waveguide structure combined with a cantilever beam. Under acceleration, the output waveguide optical power changes, which is a function of acceleration. The mathematical model of the mechanical sensing element in terms of proof mass, damping, and spring constant is formulated. Here, different aspects such as beam deflection, bending stress, and breakdown acceleration are incorporated into the formulation. Based on the analysis, the optimum mechanical structure for intensity modulated MOEM accelerometers are designed. We report for a typical uniform cantiliver beam of type I (3 mm x 3 mm x 0.38 \mu m) accelerometer, mechanical sensitivity of 0.15 \mu m/g, minimum detectable acceleration of 4.7 \mu g/root Hz at an optimum power of 500 \mu W, range of +/- 25 g, a bandwidth of 1.59 kHz, breakdown acceleration of 5.1 x 10(4) g and cross-axis sensitivity of 0.001%. The results in the case of nonuinform beam cantiliver accelerations are sensitivity of 2.15 \mu m/g, minimum detectable acceleration of 0.27 \mu g/root Hz range of +/- 1.8 g, bandwidth of 0.411 kHz, breakdown acceleration of 2987 g and cross-axis sensitivity of 0.001%