Optical performance of miniature all-fiber phase modulators with ZnO coating

Miniature all-fiber phase modulators with a radially symmetrical piezoelectric ZnO jacket have been characterized using a Mach-Zehnder interferometer over a wide frequency range from 50 Hz to 50 MHz. The frequency response of the modulators consists of two flat broad-band regions and various resonances. The maximum phase shifts measured in the broadband and resonance regions are 0.1 and 7.5 rad/V/meter of fiber, respectively. A linear dependence of the phase shift on the applied voltage up to 60 V (peak-to-peak) is observed in the broad-band region.