Dynamic displacement measurements with a dual-cavity fiber Fabry-Perot interferometer

摘要

An extrinsic fiber Fabry-Perot interferometric sensor is reported for use in vibrometric applications. The sensor operateson the principle of a "virtual" dual-cavity generated within the sensing arm due to the introduction of a birefringentelement into the optical path of the sensing cavity. The resulting two sets of "phase-shifted" interference signalsproduced allowed non-ambiguous directional detection as well as improved resolution in displacement measurements.Experimental displacement data obtained using the fiber interferometer were found to be in good agreement with thereference sensor employed. The potential for overcoming polarization-induced signal fading is also qualitativelyillustrated.