Fabrication and performance evaluation of reflectorless refractive index fiber optic sensors using etched enhanced backscattering fibers

International audience ; We propose and evaluate a technique for the fabrication and interrogation of fiber-optic refractive index (RI) sensors based on etched MgO-based nanoparticle doped fibers. The discussed method does not require to inscribe a reflective element into the fiber. Instead, light backscattered by the fiber can give sufficient information that is necessary for detection, by performing the cross-correlation of Rayleigh scatter signatures in the etched zones. The performance of the sensor is monitored using distributed sensing, which allows to interrogate several points along the length of the fiber. The sensitivities of several etched fibers are compared. The largest sensitivity that has been achieved is 45.95 nm/RIU (RI units), with the possibility of implementing temperature compensation.