Evaluation of an interrogation system of fiber Bragg sensors conditioned with a PZT based tunable filter

Application of fiber Bragg sensors has grown in different engineering domains due to high performance of such measurement method. Usually the all measurement chain is completely performed in the optical domain. However, to adapt the output of the interrogation system to a signal measurable with low cost optoelectronic devices would become a good approach in order to improve the usage of this technique. The paper describes a new solution based on the introduction of a tunable filter in the conventional interrogation system. Electric transducers and micro-actuators are used to precisely tune the filter FBG and measure the imposed displacement in order to calculate the applied strain passing to the electric domain most of the processing. Since the filter FBG and the sensor itself are matched, knowing the measured strain with the filter it allows at measuring the balanced strain on the sensing FBG