Optical fiber accelerometer based on a silicon micromachined cantilever

Adaptive opto-electromechanical silicon-on-insulator increased bandwidth accelerometer

Abstract

This paper studies the construction of a compact one-dimension-sensing iscreased bandwidth photonic accelerometer using cascaded groups of continued sections of a 50 ng seismic mass each attached to the silicon beams of two under etched slot waveguide electrostatic phase shift elements acting as voltage-controlled adaptive-precision springs. The accelerometer sensitivity is shown to be significantly increased by applying equal electrode voltages. Simulation results indicate that the sensitivity dynamic range is about 76 dB combining both open-loop and closed-loop voltage control of the sensor. The operation bandwidth of the accelerometer may be increased up to 250 kHz due to the cascaded multi-section architecture of the sensor. This advantage gives significant relief to the limitation in bandwidth response of single section counterparts. The sensor may be designed to detect impact accelerations up to 104 ms−2 and yet can still be electrostatically driven to detect sub-gravitational accelerations. The application of negative feedback voltage control to hold the seismic mass at close distances from a standstill is shown to significantly increase the acceleration detection range. The construction uses all in-plane components based on a silicon-on-insulator template with 300 nm of silicon core thickness. The proposed electromechanical suspension system and the electric feeding arrangements are the most simple. The accelerometer performance is theoretically deterministic. The study is based on performing numerical analysis for the electromechanical suspension system. The waveguides are simulated utilizing the VPIphotonics industry standard. Applications may include the automobile and aerospace industries, underwater sonar, industrial ultrasonic detection, seismology predictions, and medical ultrasonography.

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