A high-resolution joint demodulation algorithm for the fiber-optic low-finesse extrinsic Fabry-Perot interferometric sensor

In order to improve the resolution of the demodulation algorithm of the fiber-optic low-finesse extrinsic FabryPerot interferometric (EFPI) sensor, this paper presents a joint demodulation algorithm based on the synchronous squeezing wavelet transform phase extraction method and the weighted cosine similarity approach. This algorithm combines the advantages of the synchronous squeezing wavelet transform phase extraction method which can achieve high resolution in dynamic measurement, with the weighted cosine similarity method which can reduce signal interference to obtain high resolution. In the experiment, the joint demodulation algorithm realizes a high-resolution measurement of the EFPI sensor, reaching 0.020 nm and the greatest fluctuation 0.053 nm with an initial cavity length of 60 mu m. The resolution of the joint demodulation algorithm has shown promising result at the sub-nanometer level.