An Ultrahigh-Linearity MOEMS Accelerometer Based on a Self-Traceable Grating Interferometer

The linearity of the accelerometer directly affects its measurement accuracy and applicability, making it a key metric in the development of high-performance accelerometers. In response, this article proposes an ultrahigh-linearity MOEMS accelerometer based on a self-traceable grating (STG) interferometer. The accelerometer integrates an MEMS resonator with an STG interferometer based on chromium (Cr) atom transition frequency⁷S ${}_{{3}}\to {}^{{7}}$ P₄, enabling direct traceability of displacement to the International System of Units (SI) “meter.” Specifically, the average pitch of the Cr grating used is (212.781 ± 0.008) nm ( ${k} = 2$ ), showing outstanding uniformity and long-term stability. Furthermore, the compact interferometer design gives it an overall size of just $7.5\times 7.5\times 2$ cm, facilitating portable measurements in practical applications. Experimental results show that the accelerometer achieves ultrahigh performance with a nonlinearity of 0.04%. The device also demonstrates a sensitivity of $13.77~\mu $ m/g within a measurement range of ±1.6 g, with a noise floor of $9.6\times 10^{\text {-7}}$ g/ $\surd $ Hz. The integration of STG technology with the MEMS resonator offers a scalable solution for high precision, field-deployable accelerometer measurements, greatly improving measurement linearity and traceability.