Development of an optical fiber based interferometer for small vibration measurements

A development of fiber based interferometric vibrometer (FOIV) for small displacement measurements has been described in this paper. The FOIVs can, basically, be classified into 4 main types: Michelson, Mach-Zehnder, Sagnac, and Fabry-Perot interferometers respectively. However, a fiber based Fabry-Perot interferometric vibrometer has thus been demonstrated for the research proposed. By using the excitation frequency range of 10–500 Hz to the moving target, the output displacement measured by the fiber interferometer can thus be obtained of 0.65–4.58 μm over 20 times of repeatability. Moreover, the output displacement range of 1.1–15.06 μm has also been resulted when the variation of excitation amplitude of 300–3,000 mV are employed. The experimental results show the high capability of the fiber based interferometric sensor for small dynamic vibrational measurements with the resolution of λ/2.