Fibre optics monitoring
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Principles, advantages, and key points of fibre optics monitoring
Fibre optics are known to be excellent telecommunications cables. In other words, when a light signal is emitted from one end, it propagates very quickly over long distances with virtually no loss.

However, any light signal passing through a fibre necessarily interacts with its constituent elements.

These interactions result in successive micro-reflections of light, extremely small but measurable.

To simplify, these reflections are proportional to a function of the fibre's temperature and its length variation along the fibre's axis, where the interactions occur. Thus, it is sufficient to determine – and this is done using devices called « optoelectronic interrogators » – the characteristics of the emitted signal and the successively reflected signals to transform the fibre into a series of distributed longitudinal thermometers and extensometers, capable of continuously measuring the temperature and the elongation/contraction of the fiber along its entire length.

It is this capability of fibre optics that is used with « fibre optics monitoring », which consists in installing fibre optics cables where deformations or temperature anomalies are expected within the structure or at its surface when it does not behave as expected.
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Services offered
Design phase

We handle the entire design of our systems, from the initial preliminary design to assisting with tender preparation and anticipating procurement needs




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Work phase

We ensure rigorous monitoring of fibre optics installation, anticipate potential site issues, and guarantee a compliant, ready-to-use installation without any rework




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Operation phase

We provide powerful analytical tools, train your teams in their use, and ensure comprehensive and personalized support



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Design phase : thermo-hydro-mechanical modeling of the structure, simulation testing of the system's proper functioning, anticipation of supplies, and assistance in drafting calls for tenders

A pioneer, alongside EDF, in fibre optics infrastructure monitoring, geophyConsult has mastered all the key aspects of designing such systems.

Thus, through simulation of the thermo-hydraulic behavior of representative cross-sections of the structure, the company can determine, during the preliminary design phase, whether the proposed monitoring system will deliver the expected benefits and, if so, the precise locations for the location of the fibre optics cables to optimize signal-to-noise ratios.
Experienced in managing the lead times for fibre optics cables and optoelectronic interrogators, the firm is also capable of developing realistic project timelines (which, in some cases, can be a deciding factor in whether or not to invest in the recommended solution).

Finally, accustomed to drafting calls for tenders or adding fibre optics sections to existing works contracts, the company supports its clients in drafting all stages of their projects, from the preliminary technical phases (preliminary design, detailed design, preliminary and final design) to the awarding of contracts and the selection of candidates (tender documents).


This capability, developed over more than 15 years, allows geophyConsult, if necessary, to guarantee the sensitivity, reliability, and feasibility of the systems it recommends and/or to contribute to the insurability of the structure under consideration.
Work phase : assistance with candidate evaluation, supply scheduling, site data collection, site control procedures and site acceptance

A pioneer, alongside EDF, in fiber optic infrastructure monitoring, geophyConsult has mastered all the key aspects of installing a fibre optics monitoring system.

With its extensive experience in managing these types of installation projects, the company frequently assists its customers throughout the implementation of their monitoring system projects.


geophyConsult has consistently demonstrated its ability to anticipate and prevent all site-related risks directly linked to the implementation of fiber optic monitoring systems.




The acceptance testing of the systems whose installation was supervised by geophyConsult has always gone perfectly, ensuring that no hidden defects were discovered in the years that followed, that all site data was properly collected, and that subsequent operation did not require any further site visits.
Operation phase d'exploitation : local or web-based software suite for automatic or semi-automatic data analysis, with staff training if needed and, again if needed, remote assistance option ; enhanced remote analysis during crisis situations

A pioneer, alongside EDF, in fiber optic infrastructure monitoring, geophyConsult has mastered all the key aspects of operating a fibre optics monitoring system.

This allows the firm to support its customers in integrating fiber optic data into existing databases or in setting up infrastructure databases. It also knows how to retrieve supplementary data from public databases for fibre optics data analysis (such as meteorological data for the monitored area). The company also implements data backup and archiving procedures tailored to the needs of infrastructure managers (both locally and in the cloud).

Furthermore, geophyConsult offers its customers practical tools for simplified Operational Maintenance (with supervised and digitally signed validation of the latest recordings). To this end, the company is able to offer automatic hardware or software systems for sending SMS or email alerts in the event of exceeding thresholds on certain data, or of network connection failure or power supply failure of certain critical monitoring modules.




geophyConsult has finally developed and validated, on real-world projects, all the user-friendly software modules necessary for rapid or in-depth data analysis. These modules include the automated or semi-automated generation of relevant parameters for monitoring maintenance and/or structural safety, interactive and educational representations of these parameters, and the output of these parameters on 2D or 3D maps or base plans provided by customers.

The outputs of these modules are compatible with the main GIS standards on the market.

The modules of the geophyConsult suite can be assembled into a Windows® executable, which serves as the control and operating software for the monitoring system (for on-site management of the monitoring system by the customer's team), or encapsulated in a software suite accessible via the geophyConsult cloud. This cloud-based suite is a secure Windows® web interface running in the same environment as the customer's computer, making it very user-friendly (for remote data analysis management by the customer or one of their subcontractors). In such situations, geophyConsult most often assists its customers with the remote processing of their fibre optics data during crisis periods (regional flooding, etc.). Indeed, the customer's staff is usually too busy to handle this task. The company is then, where applicable, responsible for carrying out certain regulatory post-event inspections triggered by the exceptional event that caused the crisis.

When operations are intended to be carried out internally, geophyConsult is generally tasked with training the customer's staff in the analysis of their fibre optics data.

Finally, the company can assist its clients in protecting their information systems, through which the sensitive monitoring data is transmitted.

geophyConsult is currently at the forefront of all known methods for interpreting fibre optics monitoring data (gradient method, Heat Pulse Method, SACRE, etc.). Furthermore, the company has developed, most often for or with EDF, high-performance leakage models that, under certain conditions, can determine leakage rates or reveal the anomalies being sought within particularly intense noise (MORITO model, etc.).
References
Until now, mostly in partnership with EDF, geophyConsult has designed, overseen the implementation, co-operated or operated during the learning phase, and maintained in operational condition more than 40 fibre optics monitoring systems. These systems currently monitor 110 km of infrastructure and represent more than 135 km of laid fiber (plus 635 km of fiber currently being installed in the Grand Paris Express tunnels, which will ultimately contribute to the monitoring of more than 165 km of underground tunnels). The instrumented structures range from navigation and hydroelectric canals to river embankments, including a reinforced concrete dam and dams protected by geomembranes. Some of these structures are under continuous load, while others are monitored only during flood periods.

The measurements carried out range from passive Raman temperature measurements to Brillouin or Rayleigh type strain measurements, including Brillouin temperature measurements and the implementation of active temperature measurements, with heating to remain operational during annual periods of temperature inversion, or to quantify leakage rates.
Fibre optics monitoring leafleft in the pdf format
Fibre optics monitoring leaflet
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