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.