Improving the strain measurement accuracy in OFDR by suppressing residual phase noise

This paper proposes an optimal matching method between the auxiliary interferometer delay fiber and the device under test, aimed at improving strain measurement accuracy in optical frequency-domain reflectometry (OFDR) by minimizing residual phase noise (RPN). The method achieves a spatial resolution of 2 mm and strain measurement accuracy better than 1.5 με (2σ) within the optimal matching range of a hundred-meter test fiber.