Noise suppression of a micro-grating accelerometer based on the dual modulation method

The micro-grating accelerometer, as a representative micro-optical electromechanical system accelerometer, is studied widely on account of the advantages of small size and high-resolution performance. The extreme accuracy of the micro-grating accelerometer is restricted mainly by the noise floor. In order to improve the performance of the micro-grating accelerometer, a dual modulation method is proposed, which is combined with intensity modulation and phase modulation. The intensity modulation can move the signal to a high frequency, and the light source noise is suppressed perfectly by combining phase modulation. The dual modulation method is verified by constructing the micro-grating accelerometer prototype. Based on the two conditions above, the impact of 1∕f noise is diminished. By comparison, the fluctuation of the system at 0.01 g (1 g 9.8 m∕s²) is reduced by about 3 dB, which is in line with expectations. The power spectral density image shows that the system noise floor reaches −50 dB with a decrease of about 10 dB. We hope that the low-noise micro-grating accelerometer will be used generally in the future.