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

Area of Science:

• Materials Science
• Mechanical Engineering
• Optical Engineering

Background:

• Traditional accelerometers are susceptible to electromagnetic interference and temperature variations.
• There is a need for robust, high-resolution vibration sensors in harsh environments.

Purpose of the Study:

• To design, manufacture, and test a silicon inertial optical sensor for low-frequency vibration measurements.
• To evaluate the feasibility of using micro-machined sensing elements and air interferometry for vibration detection.

Main Methods:

• Finite Element Analysis (FEA) was used to optimize three accelerometer designs.
• The highest performing accelerometer was manufactured and tested.
• An air interferometer was employed for detection, avoiding electrical signals.

Main Results:

• The developed optical vibration sensor demonstrated high performance at low frequencies (< 2 kHz).
• The sensor operates at temperatures above 85 °C with a resolution of 17.5 nm.
• The fabrication process utilizes a silicon wafer with both sides etched.

Conclusions:

• It is feasible to design and manufacture a cost-effective optical vibration sensor for harsh environments.
• The sensor's design eliminates susceptibility to electromagnetic interference and large temperature variations.
• The technology offers a high-resolution solution for mechanical vibration measurement.