基于可调谐激光器的光纤法珀振动传感器解调技术

Demodulation Technology of Fiber Fabry-Perot Vibration Sensor Based on Tunable Laser

针对非本征型光纤法珀干涉仪动态解调,研究了一种基于可调谐激光器的双波长正交相位解调方案。可调谐激光器具有波长切换速度快、调谐范围广的特点,克服了传统双波长正交相位解调中光功率不平衡和直流分量难以计算的问题。利用可调谐激光器宽范围的线性扫描(1530-1560 nm)得到EFPI传感器的干涉谱,通过干涉谱计算出EFPI传感器的初始腔长122.581μm和直流分量3.4 V,同时确定两正交波长,然后利用反正切原理对EFPI传感器的腔长进行解调。搭建双波长正交相位解调系统,在2.25 kHz的频率以及不同的加速度下,对EFPI振动传感器进行解调。结果表明,该系统可实现不同腔长变化量的解调。

Aiming at the dynamic demodulation of extrinsic fiber Fabry-Perot interferometric,a dual-wavelength quadrature phase demodulation scheme based on a tunable laser is studied.The tunable laser has the characteristics of fast wavelength switching speed and wide tuning range, which overcomes the problems of unbalanced optical power and difficult calculation of DC component in traditional dual wavelength quadrature phase demodulation.The interference spectrum of the EFPI sensor is obtained by using a wide-range linear scan of the tunable laser(1530~1560 nm).Through the calculation of interference spectrum, the initial cavity length of the EFPI sensor is 122.581 μm and the DC component is 3.4 V,the two orthogonal wavelengths are determined at the same time.Then the cavity length of the EFPI sensor is demodulated by using the arctangent principle.A dual-wavelength quadrature phase demodulation system is built to demodulate the EFPI vibration sensor at the frequency of 2.25 kHz and different accelerations.The results show that the system can demodulate different cavity length changes.