High-precision distributed magnetic field sensing using polarization-sensitive TGD-OFDR based on quaternion analysis

Fiber-based distributed magnetic field sensing holds significant research and application potential in high-intensity magnetic field measurement scenarios, such as nuclear reaction monitoring and electromagnetic pulse detection. However, existing polarization-sensitive reflectometry techniques face critical limitations, including restricted measurement distances and insufficient sensitivity. To address these challenges, we propose a novel, to the best of our knowledge, sensing approach based on polarization-sensitive time-gated digital optical frequency-domain reflectometry (TGD-OFDR) that quantifies magnetic field intensity through analysis of the state of polarization based on a quaternion. Experimental results demonstrate a breakthrough sensing distance of 10 km with a measurement precision of 1.75 mT for the magnetic field.