Author(s): Zhang, Jianxiang; Huang, Wenzhu; Zhang, Wentao; Li, Fang

Source: JOURNAL OF LIGHTWAVE TECHNOLOGY Volume: 39 Issue: 15 Pages: 5183-5190 DOI: 10.1109/JLT.2021.3082774 Published: AUG 1 2021

Abstract: In the distributed feedback fiber laser sensor interrogation based on 3x3 coupler, the asymmetry of the 3x3 coupler and the inconsistency of detectors lead to harmonic distortion in the result. This paper presents an improved method that combines the 3x3 coupler and the extended Kalman filter (3x3-EKF method) to effectively suppress the harmonic distortion in real-time. The coefficients of the three ellipses formed by every two-channel interference fringes were estimated using EKF. The system parameters were corrected based on these coefficients to eliminate the dependence on the idealization of 3x3 coupler and detectors. The result shows that the 3x3-EKF method can update the system parameters with a frequency up to 500 kHz. A total harmonic distortion less than 0.1% can be achieved with signal frequency ranging from 20 Hz to 1 kHz. Besides, the system shows a minimum detectable wavelength shift of 3.1 x 10(-7) pm/root Hz @ 1 kHz, and a large dynamic range of 135 dB @ 100 Hz.

Accession Number: WOS:000673624400036

ISSN: 0733-8724

eISSN: 1558-2213

Full Text: https://ieeexplore.ieee.org/document/9439196/