Three-channel low-frequency fiber-optic voltage sensor

Abstract

We demonstrate a frequency-multiplexed three-channel fiber-optic interferometric dc and low-frequency voltage sensor based on the electrostrictive effect in lead magnesium niobate transducers. The sensor relies on the nonlinear transduction mechanism in electrostrictive materials for frequency-division multiplexing by use of a single interferometer and a single unmodulated laser. To our knowledge this is the first direct measurement of three low-frequency voltage signals with a single fiber-optic interferometer. Demonstrated cross talk between channels is less than −75 dB. The cross talk is shown to be caused by the nonlinear output of the interferometer at large applied strains.