A miniaturized, highly integrated MEMS diffraction-grating accelerometer with 15.1 Hz resonance and 2 ng/√Hz self-noise

We present a miniaturized, highly integrated MEMS optical accelerometer based on a diffraction-grating interferometric readout, targeting low-frequency, weak-motion measurements relevant to seismic observation. A novel mechanical architecture combined with a “sandwich” assembly approach enables a low fundamental resonance of 15.1 Hz while preserving a compact and robust package. At the system level, the laser source, MEMS interferometric module, and photodetector are integrated into a single enclosure measuring 4.5 cm × 3.5 cm × 3 cm, reducing alignment complexity and supporting field deployment.

Noise characterization demonstrates a self-noise of 2 ng/√Hz, indicating nanogram-level sensitivity in a small-form-factor instrument. We will describe the device concept, integration strategy, and dynamic/noise test methodology, and discuss how this accelerometer can complement existing seismic sensors for applications such as microtremor monitoring, dense temporary deployments, and near-field ground-motion characterization where size, power, and self-noise are critical constraints.