Self-correction-iterative method enabled 15,000 με ultra-large dynamic range distributed strain sensing system

Distributed optical fiber strain sensors based on optical frequency domain reflectometry (OFDR) are increasingly utilized in applications including medical diagnostics and geological exploration, where both high spatial resolution and a large strain measurement range are required. However, the performance of OFDR is limited by positional and spectral mismatches, resulting in an inherent trade-off between the dynamic range and spatial resolution. Here, a distributed strain sensing system with an ultra-large dynamic range is proposed. By introducing the self-correction-iterative algorithm for high-precision positional compensation, the system achieves high spatial resolution and an ultra-large strain measurement range simultaneously. In addition, an active contour model is employed to nondestructively extract the strain profile from the position-corrected demodulation image. Experimental results show that the proposed scheme achieves the up to 15,000 με strain demodulation with a high spatial resolution of 0.8 mm and a relative error of only 0.16%, offering a groundbreaking solution for distributed strain sensing applications that require a large dynamic range and high resolution.