A high sensitive fiber-optic strain sensor with tunable temperature sensitivity for temperature-compensation measurement

A high sensitive fiber-optic strain sensor, which consists of a cantilever, a tandem rod and a fiber collimator, was proposed. The tandem rod, which transfer the applied strain to the cantilever, was used for tuning the temperature sensitivity from -0.15 to 0.19 dB/degrees C via changing the length ratio of the rods. Moreover, due to the small beam divergence of the collimator, high strain sensitivity can be realized via incident-angle sensitive detection-mechanism. A strain detection-range of 1.1 x 10(3) mu epsilon (with a sensing length of 21.5 mm), a detection limit of 5.7 x 10(-3) mu epsilon, and a maximum operating frequency of 1.18 KHz were demonstrated. This sensor is promising for compensating the thermal-expansion of various target objects.