Fiber Optic Sensing Technologies for Structural Health Monitoring

Fiber optic sensing has emerged as a transformative approach for monitoring the integrity of civil, mechanical and aerospace structures. By embedding or surface-mounting optical fibres equipped with tailored sensing elements, it is possible to track strain, temperature and vibration continuously over distances ranging from metres to kilometres. Core technologies include fiber Bragg gratings (FBGs) for point and quasi-distributed measurements, and distributed optical fibre sensing (DOFS) methods based on Rayleigh, Brillouin or Raman scattering. These systems offer immunity to electromagnetic interference, resistance to corrosion and multiplexing capabilities that greatly reduce cabling complexity. They have been deployed for health monitoring of bridges, dams, pipelines, tunnels and composite aircraft panels, supporting early damage detection, load evaluation and life-cycle management. Recent advances in interrogation hardware, demodulation algorithms and sensor packaging have boosted spatial resolution to the centimetre scale while extending sensing ranges to kilometre-long networks. Integration with machine learning and digital-twins now enables real-time condition assessment and predictive maintenance, underscoring the global potential of fibre optic sensing to enhance infrastructure resilience and safety.

Research from Nature Portfolio

Recent work has demonstrated a machine learning-assisted approach to demodulate chirped-FBG signals for sub-surface thermal mapping in additively manufactured metals. By embedding miniature chirped gratings within the powder bed fusion process and applying a trained neural network, spatial resolution was improved from the millimetre to the micrometre scale (approximately 28.8 µm). A novel embedding technique minimised sensor damage and ensured reliable contact between fibre and part. The resulting system achieved rapid, high-resolution measurements of thermal gradients during layer-wise printing, offering new insights into microstructural evolution and pointing the way towards in situ structural-health sensing in advanced manufacturing contexts.

Fiber Optic Sensing Technologies for Structural Health Monitoring publication trend

The graph below shows the total number of articles in fiber optic sensing technologies for structural health monitoring across all publications each year (not limited to Nature Index journals).

Technical terms

Fiber Bragg Grating (FBG): A periodic modulation of refractive index in the fibre core that reflects a narrow band of wavelengths, shifting in response to strain or temperature.

Distributed Optical Fiber Sensing (DOFS): Techniques exploiting Rayleigh, Brillouin or Raman scattering along a fibre to measure physical parameters continuously over its entire length.

Raman Scattering: Inelastic scattering of light in optical fibres; the intensity of frequency-shifted backscatter is used for distributed temperature sensing.

Chirped-FBG: A fibre Bragg grating with a longitudinally varying period, enabling high spatial resolution measurements along its length.

Interferometry: Methods that detect changes in optical path length by monitoring the interference of light waves within fibre-optic structures.

References

1. Sub-surface thermal measurement in additive manufacturing via machine learning-enabled high-resolution fiber optic sensing. Nature Communications (2024).
2. A Review of Distributed Optical Fiber Sensors for Civil Engineering Applications. Sensors (2016).
3. Fibre Bragg Grating Based Strain Sensors: Review of Technology and Applications. Sensors (2018).
4. Chaos Raman distributed optical fiber sensing. Light: Science & Applications (2023).