Fiber optic sensor research is one of the pillars within the research group focusing on the development of high-performance fiber interferometers and fiber refractometers. We develop versatile fibre interferometric sensors based on the extrinsic Fabry-Perot interferometer (EFFPI) for nanometric displacement and absolute distance measurements targeting in situ applications in metrology, geophysics and biomedical engineering in both academia and industry, with the ambition to respond to hazard mitigation and population health priorities. We are also developing robust high precision fiber refractometers using a combination of different fiber technologies for in situ detection of naturally emitted greenhouse gases from the aquatic environment, such as dissolved methane in the context of global warming and climate change. Our efforts over the past 15 years have led to various projects (4 ANR, 1RTRA, 1 CERN, 2 PHC, numerous INSU CNRS, etc) all dedicated to respond to numerous science, environmental, risk and population health challenges..