An Aston University-led initiative aims to turn existing telecom cables in railways into real-time early warning systems for structural failures.
www.allaboutcircuits.com, Aug. 20, 2025 –
Aston University recently launched ECSTATIC, a €5.1 million ($5.9 million) European research project that repurposes fiber-optic telecom cables as real-time structural sensors.
Given the high cost and disruption associated with installing conventional sensor networks, ECSTATIC’s goal is to transform existing communications infrastructure into a 24/7 monitoring system.
ECSTATIC, which stands for Engineered Combined Sensing and Telecommunications Architectures for Tectonic and Infrastructure Characterisation, attempts to augment the function of fiber-optic cables from just data carriers to active environmental sensors.
The proposed system works by transmitting ultra-precise laser pulses through existing buried optical fibers. When surface or subsurface forces, such as those from passing trains, exert stress on the cables, they induce microscopic shifts in fiber geometry. These physical changes affect the phase and polarization of the transmitted light. The resulting optical disturbances create a dynamic signature corresponding to the external mechanical stimuli.
To measure and decode these signals, ECSTATIC integrates dual-microcomb photonic chips with advanced digital signal processing and AI algorithms. Dual-microcomb technology supports simultaneous multi-frequency light transmission and detection that substantially enhances the granularity and sensitivity of measurements. AI algorithms trained on known structural conditions then interpret the resulting optical fingerprints to differentiate normal usage from early indicators of damage or fatigue.
Notably, the system is designed to operate without interfering with data traffic. Such a non-invasive architecture allows fiber sensing and telecommunications to coexist on the same cable, thereby eliminating the need to install new infrastructure.
In addition to infrastructure monitoring, ECSTATIC’s sensing platform can detect seismic activity, oceanic disturbances, and other environmental factors using the same physical hardware. In these cases, the platform will aim to both identify damage and classify and characterize structural and tectonic behavior in real time.
The main physical principle enabling ECSTATIC’s sensing capability lies in the interaction of light with perturbations in the fiber medium. Specifically, the system exploits how strain and temperature variations affect the phase and polarization states of light propagating through the core.
Phase sensing is based on interferometry. When an optical fiber is deformed, even minutely, the path length of the light changes, resulting in a phase shift. These phase changes can be measured with high precision to detect vibrations or strains on the order of nanometres. By using coherent detection methods, the system can extract this phase information to infer mechanical influences acting on the fiber.
Polarization-based sensing adds another layer of diagnostic capability. In ideal conditions, light maintains a stable polarization state as it travels through a fiber. However, environmental stress (bending, twisting, or compression) alters the fiber’s birefringence. These changes rotate the polarization state and offer additional data on the type and direction of external forces.
When combined, phase and polarization measurements enable a spatially resolved, multi-dimensional assessment of external stimuli along the length of the fiber. While point sensors capture data from discrete locations, fiber-optic sensing provides continuous coverage, turning an entire cable into a distributed sensor.
The dual-sensing approach significantly enhances the ability to distinguish between different types of mechanical inputs, such as the difference between routine vibrations from traffic and unusual stress patterns that may precede structural failure.
The project’s first field trial, underway in a major U.K. city, uses a heavily trafficked railway viaduct to test whether buried fiber-optic cables can detect subtle shifts, stress, and vibrations in infrastructure without installing new hardware. The initial demonstration site, a Victorian-era railway viaduct supporting tens of thousands of trains annually, provides a high-vibration environment ideal for testing the approach.
With billions of kilometers of optical fiber deployed worldwide, the potential to scale this technology without massive capital expenditure is unprecedented. If successful, the trial outcomes will inform standards for integrating fiber sensing into existing networks. Availability of the first deployable systems is expected following project validation phases in 2027–2028.