Fiber optics sensor for sub-nanometric displacement and wide bandwidth systems

In this paper, we report fiber optics sensor with sub-nanometric resolution and wide bandwidth. It relies on an increase of the reception fibers number and on low-noise electronics. Moreover, a reference channel has been implemented using a semi-reflective plate to eliminate the source fluctuations and the fiber sensor was isolated to limit external influence of temperature and pressure. Thus we achieve both a sub-nanometric resolution on a 400 ms integration time and a long-term drift as low as 40 nm h−1. The setup has been also adapted to high speed applications by increasing the bandwidth up to 38 kHz. It can display a 28 nm peak-to-peak limit of resolution on an aluminized piezoactuator. It has been successfully used to test the resonance frequency of a vibrating plate actuated by two high-frequency prototypes of piezoactuators. These improvements lead to low cost fibers optic sensors interesting for non-contact displacement measurements with high sensitivity.