Electromechanical measurements of electric field-induced displacements of fibers

In this paper we report on a development of a new method for measurements of electric field-induced displacements in a cylindrical geometry (optical fiber with the deposited piezoelectric film). The measurement setup is based on a commercially available Fotonic Sensor MTI 2000 (MTI Inc.). Major disadvantages of measurement by standard techniques (e.g., interferometry) such as low reflectivity, high roughness of the coating resulting in poor fringe quality, and big displacement range are successfully avoided using a special configuration of an optical probe and a sample. The method allows performing investigations of electromechanically induced vibrations in a broad frequency range (from 0 up to 150 kHz) and various combinations of ac and dc voltages. The capabilities of the proposed method are validated by strain measurements of an optical fiber cantilever beam covered by Pb(Zr,Ti)O(3) thick film.