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 frequency<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup>S<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${}_{{3}}\to {}^{{7}}$ </tex-math></inline-formula> P<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub>, 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 (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k} = 2$ </tex-math></inline-formula>), showing outstanding uniformity and long-term stability. Furthermore, the compact interferometer design gives it an overall size of just <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$7.5\times 7.5\times 2$ </tex-math></inline-formula> 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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$13.77~\mu $ </tex-math></inline-formula>m/g within a measurement range of ±1.6 g, with a noise floor of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$9.6\times 10^{\text {-7}}$ </tex-math></inline-formula> g/<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\surd $ </tex-math></inline-formula>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.