Remote-distance high spatiotemporal resolution phase-sensitive optical frequency-domain reflectometer

This work presents a groundbreaking phase-sensitive optical frequency-domain reflectometry (φ-OFDR) technology that overcomes the longstanding trade-off between long-distance operation and high spatiotemporal resolution in distributed optical fiber sensing (DOFS), namely remote φ-OFDR. By leveraging a far-end self-referencing architecture, the system utilizes low-coherence DFB laser (tens of meters coherence length) with internal modulation to achieve coherent detection at 75 km, while maintaining a spatial resolution of 2 cm and a sampling rate of 4 kHz-surpassing conventional Nyquist limits for such long-haul fiber link. Experimental validations demonstrate multipoint vibration and chirped response up to 2 kHz. This scheme decouples temporal resolution from total fiber length, enabling microsecond-level response in targeted sensing segment. Its simplified design, combined with compatibility with advanced laser technologies, positions it as a scalable solution for higher spatiotemporal resolution within several kilometers of targeted remote sensing range, guaranteeing the capability to extend operation to hundreds of kilometers in future deployments.