UBC Theses and Dissertations

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UBC Theses and Dissertations

Design of a MEMS-based optical accelerometer with large measurable range and high sensitivity Zeng, Yiyi


MEMS Accelerometers are broadly used in the area of vibration sensor. Their applications range from seismic disturbances, to automotive industry such as airbag systems, active suspension, and smart braking. Traditionally, the acceleration is detected electrically by measuring either capacitive variations or piezoelectric signals. Those approaches suffer from a number of drawbacks, such as low sensitivity due to low signal-to-noise ratio (SNR), small dynamic range, high temperature sensitivity, etc. In this thesis, a MEMS-based optical accelerometer is designed and analyzed. The device can be fabricated on a silicon-on-insulator (SOI) wafer, on which a double-leg single-mode optical rib waveguide is used to propagate 1.55μm laser beam. The device integrates the waveguide with a mechanical oscillator, and is able to detect in-plane vibrations of the oscillator by taking advantages of optical interference. According to the analysis, the maximum working range of the oscillator can be as large as 50μm and the acceleration sensitivity can be below 1μg/Hz¹/². Device fabrication and characterization are also carried out and described in the thesis. All necessary fabrication steps and details as well as characterization setups are given. Due to several fabrication challenges in UBC (e.g. malfunctioned equipment), a complete device has not been fabricated. More fabrication and characterizations are to be continued as future work.

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