Kurzbeschreibung
(Englisch)
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The project will study and implement novel techniques and photonic tools for the development of performant distributed fibre sensors. These techniques include laser injection locking, optical wave probing by a nonlinear interaction, coherent Rayleigh backscattering and slow light effect.
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Partner und Internationale Organisationen
(Englisch)
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BE, CH, CY, CZ, DE, DK, ES, FI, FR, GR, HR, IE, IL, IT, PL, PT, RO, SE, SK, UK
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Abstract
(Englisch)
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This project aims at developing a new class of distributed fibre optics sensors using innovative configurations based on novel devices to show significantly improved performance. During this third year we have consolidated the novel sensor concept developed in our group, named 'Brillouin echoes' to highlight the formal analogy with spin echoes in nuclear magnetic resonance (BEDS technique). Simultaneously we tested a totally novel approach using dynamically generated gratings in an highly birefringent optical fibre through the intercession of stimulated Brillouin scattering (BDG technique). These new concepts are developped to achieve high spatial resolution distributed measurements, by using very short sub-nanosecond pulses while maintaining a sharp Brillouin resonance. Spatial resolutions down to a few cm have been reached, that represent an improvement of two orders of magnitude with respect to the existing technology. Thanks to the novel Brillouin dynamic grating approach, we have currently the record Brillouin distributed fibre sensor that shows the best spatial resolution (1cm) based on a pulse technique. During this year we have also developped a method named 'differential gain approach'to overcome noise and depletion and therefore increase the range detection of Brillouin echoes sensors (BEDS) from 1km to 5 km using 5 cm spatial resolution. It appears that BEDS systems can become a key and powerful configuration for the next generation of Brillouin fiber distributed sensors, combining simplicity in the hardware implementation, kilometric sensing ranges and centimetric spatial resolution, with a temperaure/strain resolution unchanged when compared to a classical system. In tight collaboration with COST partners we also demonstrated experimentally using BEDS the effect of inhomogeneities on backward and forward Brillouin Scattering in Photonic crystal fibers. Our experimental study may help to evaluate geometric variations of the fibre.
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