Ultra-sensitive in-situ sensors based on multicore fibers – CIFOM

Sensing and analyzing extremely low physical, chemical or biological quantities in situ, within hard-to-reach environments, are rapidly growing demands. Though among the best components in terms of compactness for addressing this challenge, “Lab-on fiber” concept suffers from limited sensitivity performances. On the other hand, all-fiber interferometric sensors have the potential to significantly enhance detection sensitivity. However, such probes suffer from an important phase noise in reaction to temperature of mechanical stress fluctuations, which strongly limit their applicability.

CIFOM comes within this framework. It is aimed at realizing the first ultra-stable fibered interferometric sensors by combining the best of these two approaches. Transposition of interferometric sensor concepts to fibered devices is presently hindered by the high sensitivity of optical fibers to environmental disturbances (temperature and mechanical stress fluctuations). CIFOM will overcome all of these issues by implementing the first “common-path” interferometric probe within a multicore fiber. Thermal and mechanical issues in fibered phase-interrogation approaches will then be cancelled out. The probes will be incorporated within homodyne and heterodyne interferometers to reach record in-situ detection resolution, far exceeding state-of-the-art detection performances of fiber-integrated systems. The production of such disruptive fiber probes will be enabled by a novel key technology, namely the development of a monolithic core-to-core optical interconnect integrated at one end-face of a multicore fiber. The resulting fiber sensors will be demonstrated as ultrasensitive refractometers in the detection of hazardous volatile organic compounds diluted in air and in organic/aqueous solvents (concentration down to the ppm, or below).

The integration of nano-optically driven interferometric approaches within optical fibers will lead to completely new versatility and unmatched performances in the extreme exploration of hard-to-reach physical or biological locations, thus impacting a wide panel of scientific, medical and industrial domains of high economic and societal perspectives. In that context, despite high scientific challenges, CIFOM is geared toward prototyping and the valorization of patentable outcomes. The ambition is here to bridge the gap between fundamental concepts and market-ready prototypes. Therefore, the key fundamental issues of CIFOM will be industrially addressed from the very outset of the project in order to achieve short term out-of-lab prototyping.

Such an ambition required the creation of a highly multidisciplinary consortium combining an industrial company and three research teams of an academic Institute. The consortium behind this project is unique and will enable the development and validation of this new scientific and technological approach with ambitious and highly complementary objectives covering all the key disciplines and themes of the project. The related important technology challenges will be taken up thanks to the fabrication facilities of the whole consortium, involving one of the five technology platforms of the French “Renatech” network.