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

• Published in: Optical fiber technology Vol. 76; p. 103237
• Main Authors: Guo, Hao, Wang, Qi, Tang, Jing-Ren, Jiang, Chun-Qi, Li, Shuai, Zhang, Lei, Zhang, Ke-Ke
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.03.2023
• Subjects: Demodulation algorithm; Fabry Perot sensor; Phase extraction method; Synchronous squeezing wavelet transform; Weighted cosine similarity; Weighted cosine similarity; Fabry Perot sensor; Phase extraction method; Demodulation algorithm; Synchronous squeezing wavelet transform
• ISSN: 1068-5200; 1095-9912
• DOI: 10.1016/j.yofte.2023.103237

•A joint demodulation technique with sub nanometer resolution is proposed.•The energy of spectral signal is further concentrated by synchronous squeezing.•The estimated cavity length is obtained by the phase extraction method.•Weighted vector is introduced to reduce the influence of noise on the results.•The final cavity length is obtained by the weighted cosine similarity method. In order to improve the resolution of the demodulation algorithm of the fiber-optic low-finesse extrinsic Fabry-Perot 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 μm. The resolution of the joint demodulation algorithm has shown promising result at the sub-nanometer level.