The sensor optimization is devoted to the study of the improvement of the sensor performance (sensitivity, operating interval) as a function of the radius of curvature of the micro-mirrors and the core diameter of the optical fibres. When the mode field diameter of the single mode fibre is smaller, the size of the waist image should have the same value (at a temperature or pressure value) to have a maximum coupling efficiency. During the fluctuation of T or P, the waist size image, which depends on the bend radius of the micro-mirror, scans the mode field diameter of the SMF beyond the Rayleigth range. As a result, the variation in the intensity of the reflected light is relatively faster. So, the slope of the coupling efficiency curve is quite steep. The sensitivity is improved but the range of temperature or pressure variation is shorter. Conversely, if the sizes are relatively large (SMF core as well as waist image), the scanning area is longer, so the sensitivity decreases, but the dynamic range is enlarged. This imposes a choice of detection. The main results and the structure of the sensor will be presented.
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