High-Precision Sub-Millimeter Resolution OFDR Strain Sensing System Based on Rayleigh-Scattering-Enhanced Random Fiber Grating

To address the problem that the low Rayleigh scattering intensity in single-mode fiber (SMF) limits the development of optical frequency domain reflectometry (OFDR) system. we introduce a random fiber grating-based Rayleigh scattering enhancement (RSE) in OFDR system. The random fiber grating based on RSE achieves a Rayleigh scattering intensity 40 dB higher than that of SMF, and the inter-scatterer distance is orders of magnitude smaller compared to conventional gratings, enabling the OFDR system to realize high precision and sub-millimeter resolution distributed strain demodulation solely through basic cross-correlation algorithms. The experimental results show the OFDR strain sensing system with RSE offers a maximum strain error of 3.01% across the entire enhanced Rayleigh scattering fiber under 3200 με at 0.5mm spatial resolution. This technological breakthrough opens up new possibilities for distributed optical fiber sensing technology in applications demanding high-precision, high-resolution strain measurement, such as aerospace structural health monitoring and civil engineering safety assessment.