Research pick: Good vibrations mean common sense - "Optical fibre distributed sensing system based on high-power ultra-narrow linewidth laser"

A highly precise fibre-based sensing system that can monitor and protect critical infrastructure such as power plants, borders, and military installations is described in the International Journal of Energy Technology and Policy. The system uses advanced laser technology to detect minute disturbances along optical fibres, offering a secure, real-time means of surveillance and fault detection over vast distances.

The research achieves this high precision by using high-power, ultra-narrow linewidth single-mode fibre lasers. These devices can emit light at an extremely stable and well-defined wavelength. This stability allows the system to interpret subtle back-scattered signals within the fibre with exceptional precision, using a method known as optical time-domain reflectometry (OTDR). OTDR works by sending light pulses down a fibre and measuring the light that is scattered back, revealing changes in temperature, strain, or vibration along the length of the fibre.

Laboratory tests demonstrated remarkable performance: fluctuations in transmission and central wavelength were kept below a critical level, while repeated measurements deviated by a tiny amount. This level of consistency, the paper suggests, confirms both the sensitivity and reliability of the design, combining low operational cost with the inherent safety of optical systems. The nature of ultra-narrow linewidth lasers means the signal-to-noise ratio is kept sufficiently high that accurate detection and localisation of events across extended distances can be achieved.

Conventional sensor networks rely on exposed components and electrical wiring, but this fibre-based system can be embedded directly into the ground, integrated with fences, or coiled around pipelines. This makes them resistant to tampering and environmental interference, including electromagnetic noise, extreme temperatures, and corrosion. The approach might be used to detect strain or temperature shifts that precede equipment failures or leaks in pipelines or failing integrity of bridges or tunnels. The approach is particularly suited to remote or hazardous environments, from nuclear facilities to long, unguarded borders.

Li, L., Liu, M., Wu, Q., Zhang, X., Liu, Z. and Zhang, Y. (2025) ‘Optical fibre distributed sensing system based on high-power ultra-narrow linewidth laser’, Int. J. Energy Technology and Policy, Vol. 20, No. 6, pp.17–32.