Fast Demodulation Algorithm for Multiplexed Low-Finesse Fabry–Pérot Interferometers

In this paper, we report a novel high-speed white light interferometry (WLI) demodulation algorithm for multiplexed low-finesse Fabry–Pérot interferometers (FPIs). The dependence of the demodulation speed on the number of multiplexed sensors was characterized through simulations. An experimental demonstration of 70-kHz real-time WLI demodulation of two extrinsic FPIs was conducted. Sub-nanometer spatial resolution was well achieved for both channels. The crosstalk between the two channels was characterized with respect to the cavity modulation frequency.