Enhancing DAS sensitivity through structural optimization of thin-walled cylinders

Distributed Acoustic Sensing (DAS) is a powerful technology for large-scale monitoring, but its applications are often limited by low sensitivity to weak acoustic signals. To overcome this limitation, we developed a thin-walled cylindrical DAS sensor and systematically investigated how its core structural parameters—elastic modulus, wall thickness, and diameter—influence sensitivity. A theoretical model linking the cylinder’s circumferential strain to the fiber’s optical phase shift was also developed to elucidate the enhancement mechanism. Results show that sensitivity increases exponentially when reducing the cylinder’s elastic modulus (from 193 to 2.3 GPa) or wall thickness (from 5 to 1 mm), reaching a maximum of 0.98 rad/Pa. Furthermore, sensitivity increases linearly with diameter, with an average gain of 0.02 rad/Pa per millimeter. These findings provide a practical and scalable structural design strategy for significantly enhancing DAS sensitivity, enabling more effective sensing for applications like microseismic monitoring, subsurface imaging, and weak vibration detection.