Open AccessDual-wavelength demodulation technique for interrogating a shortest cavity in multi-cavity fiber-optic Fabry–Pérot sensors
Author(s) -
Qianyu Ren,
Pinggang Jia,
Guowen An,
Jia Liu,
Guocheng Fang,
Wenyi Liu,
Jijun Xiong
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.438258
Subject(s) - demodulation , optics , fabry–pérot interferometer , physics , interferometry , coherence (philosophical gambling strategy) , interference (communication) , wavelength , materials science , telecommunications , computer science , channel (broadcasting) , quantum mechanics
This paper demonstrates, for the first time, a novel demodulation technique that can be applied for interrogating a shortest cavity in multi-cavity Fabry-Pérot (F-P) sensors. In this demodulation technique, using an amplified spontaneous emission (ASE) light source and two optical fiber broadband filters, the interference only occurs in a shortest F-P cavity that is shorter than the half of the coherence length. Using a signal calibration algorithm, two low-coherence interference optical signals with similar coherence lengths were calibrated to obtain two quadrature signals. Then, the change in the cavity length of the shortest F-P cavity was interrogated by the two quadrature signals and the arctangent algorithm. The experimental results show that the demodulation technique successfully extracted 1 kHz and 500 Hz vibration signals with 39.28 µm and 64.84 µm initial cavity lengths, respectively, in a multi-cavity F-P interferometer. The demodulation speed is up to 500 kHz, and the demodulation technique makes it possible for multi-cavity F-P sensors to measure dynamic and static parameters simultaneously. The results show that the demodulation technique has wide application potential in the dynamic measurement of multi-cavity F-P sensors.