Ultra-high resolution tilt calibration and real-time compensation for cold atom gravimeters

The angular misalignment between two Raman beams is a critical source of error in gravity measurements using cold atom gravimeters. This paper presents the design and experimental validation of an integrated optical fiber module based on the principle of optical reversibility. The proposed module enables calibration of Raman beam polarization orthogonality and overlap angles while simultaneously providing real-time compensation for gravity measurement errors induced by Raman beam misalignment through continuous monitoring of the calibration signal. Experimental results demonstrate that the module achieves a Raman mirror tilt angle calibration accuracy of 1.6 arc sec, corresponding to a gravity acceleration calibration accuracy of 0.06 μGal. The implementation of this module enhances calibration efficiency, mitigates alignment-related disturbances, and improves the overall stability of atomic gravimeter measurements. Its versatility makes it suitable for deployment in both high-accuracy stationary laboratory experiments and dynamic field applications, advancing the practical utility of cold atom gravimeters in geophysical and metrological research.