A Displacement Measurement System Based On Multiplexed Fiber Interferometry

:We propose a high stabilized displacement measurement system endowed with large range that is based on multiplexed fiber interferometry. In order to make the displacement measuring systems achieve the large-range and high-resolution purpose, we have finished theoretical analysis and experimental verification with the multiplexed fiber interferometer. Two fiber Michelson interferometers that share common-interferometric-optical path are configured by employing fiber Bragg gratings as in-fiber reflective mirrors. One of the interferometer is used to stabilize the measurement system by a feedback loop compensating the influences induced by the environmental disturbances which makes the measurement system stabile enough for on-line measurement, while the other one is for performing the measurement task. Two different wavelengths are working simultaneously in the measurement interferometer. The measurement range determined by the synthetic-wavelength interferometric signal of the two wavelengths is expanded to be larger than2mm, while the measurement resolution determined by one of the single-wavelength interferometric signals is maintained less than1nm. The displacement measurement system has achieved the large-range and high-resolution purpose that is based on multiplexed fiber interferometry.