Frequency response of a single-mode optical fiber phase modulator utilizing a piezoelectric plastic jacket

Abstract

A vinylidene fluoride-tetrafluoroethylene copolymer jacket, 120 μm thick, was melt extruded on single-mode optical fibers, 80 μm diam. The jacket was made piezoactive by poling radially. The performance of the fiber as an optical phase modulator was demonstrated over a wide frequency range, from 300 Hz to 2.5 MHz. A phase shift of 0.03 rad per volt per meter of fiber was measured in the low frequency (axially unconstrained) region, and 0.01 rad/V/m in the high frequency (axially constrained) region. A theoretical model was developed, relating the phase shift in the fiber to the elastic and piezoelectric porperties of the jacket material.