Optical Sensor, Based on an Accelerometer, for Low-Frequency Mechanical Vibrations

This article documents the design, manufacture, and testing of a silicon inertial optical sensor for low-frequency (lower than 2 kHz) applications. Three accelerometer designs optimized by parameterization using Finite Element Analysis were considered. The accelerometers were manufactured and the one with the highest performance at low frequency was chosen for testing, which was attached to a steel package. The feasibility of using probes, based on micro-machined sensing elements, to measure mechanical vibrations with high resolution was also studied. The detection is performed with an air interferometer, eliminating the need for electric signals that are susceptible to electromagnetic interference and large temperature variations. From the fabrication technology using only a silicon wafer with both sides etched, the frequency response of the sensor, temperature operation (higher than 85 degrees C) and with a resolution of 17.5 nm, it was concluded that is achievable and feasible to design and manufacture an optical vibration sensor for potential harsh environments with a low cost.

Automated summary

This article documents the design, manufacture, and testing process of a silicon inertial optical sensor for low-frequency applications. Three accelerometer designs were considered and the one with the best performance at low frequency was chosen. The feasibility of using micro-machined sensing elements for high-resolution measurement of mechanical vibrations was also studied.