Study of coupling single-mode fiber-optic sensor for strain and vibration measuring

A new kind of coupling single-mode fiber-optic sensor used the coupler´s coupling region as sensitive unite is presented. The theory of coupling single-mode fiber-optic sensor is analyzed. According to the relation between the coupler´s coupling ratio with the length and refractive index of its coupling region, strain and vibration measuring technology with this kind of sensor are put forward. The strain and vibration experimental system based on micro strain instrument and cantilever are setup and given in detail. Strain response of coupling single-mode fiber-optic sensor is investigated and the result is excellent. The dynamic experiments of coupling single-mode fiber-optic sensor compared with piezoelectric sensor are accomplished and good response of coupling single-mode fiber-optic sensor is approved. Experimental results indicate that the coupling single-mode fiber-optic sensor is feasible to measure strain and vibration signal practically.