SagnacAssisted Enhanced OTDR for Distributed Acoustic Sensing: A Standardized Benchmark and Engineering Evaluation Framework

Researchers have developed an enhanced fiber-optic sensing system that combines phase-sensitive optical time-domain reflectometry with Sagnac interferometry to improve distributed acoustic sensing (DAS) performance over long distances. The new architecture addresses signal degradation issues and achieves 89.79% accuracy in acoustic event recognition, with an open-source benchmark framework for future development.

This research addresses a critical limitation in distributed acoustic sensing technology, which is increasingly deployed for infrastructure monitoring, seismic detection, and security applications. The Sagnac-assisted enhancement tackles a fundamental challenge in phase-sensitive OTDR systems: polarization-induced fading that causes signal degradation over sensing distances exceeding several kilometers. By combining two optical sensing approaches, the architecture maintains continuous phase response even when conventional channels weaken, significantly improving reliability in real-world deployments.

The work emerges from the broader evolution of fiber-optic sensing as a cost-effective alternative to traditional distributed sensor arrays. DAS systems leverage existing fiber-optic infrastructure—already buried globally for telecommunications—to create spatially continuous acoustic monitoring across tens of kilometers. This dual-use potential has driven investment from energy companies, infrastructure operators, and defense applications seeking real-time environmental monitoring.

The benchmark framework provided carries substantial industry value. By establishing standardized evaluation protocols comparing feature-engineering, shallow learning, and deep fusion models under identical conditions, the research enables objective performance comparisons and reproducible results. This standardization accelerates adoption by removing ambiguity around which methods work best under specific deployment conditions. The 5% nuisance alarm rate and emphasis on macro-F1 and false negative rates—rather than accuracy alone—reflects real operational concerns in safety-critical applications.

The open-source implementation democratizes advanced DAS capabilities, enabling smaller operators and researchers to deploy enhanced systems without developing proprietary solutions. Future developments will likely focus on extending the approach to longer distances, improving computational efficiency for real-time processing, and adapting the framework to specialized sensing applications beyond acoustic event detection.

• →Sagnac-assisted architecture eliminates polarization-induced fading that degrades conventional phase-sensitive OTDR performance over long fiber distances
• →Dual-branch fusion models outperform traditional approaches with 89.79% accuracy and 5% nuisance alarm rate on balanced test sets
• →Open-source benchmark protocol enables standardized evaluation of DAS methods and accelerates technology adoption across industries
• →Deployment success depends on multiple metrics beyond accuracy, including macro-F1, false negative rate, and latency for real-world applications
• →The work leverages existing global fiber-optic infrastructure for cost-effective distributed acoustic sensing without new cable installation