Zhang Wanjin, Lu Ping, Qu Zhiyuan, Zhang Jiangshan, Wu Qiang, Liu Deming
Wuhan National Laboratory for Optoelectronics (WNLO) and National Engineering Laboratory for Next Generation Internet Access System, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China.
Huazhong University of Science and Technology Research Institute, Huazhong University of Science and Technology, Shenzhen 518000, China.
Sensors (Basel). 2022 Mar 24;22(7):2488. doi: 10.3390/s22072488.
A large-dynamic-range and high-stability phase demodulation technology for fiber-optic Michelson interferometric sensors is proposed. This technology utilizes two output signals from a 2 × 2 fiber-optic coupler, the interferometric phase difference of which is π. A linear-fitting trigonometric-identity-transformation differential cross-multiplication (LF-TIT-DCM) algorithm is used to interrogate the phase signal from the two output signals from the coupler. The interferometric phase differences from the two output signals from the 2 × 2 fiber-optic couplers with different coupling ratios are all equal to π, which ensures that the LF-TIT-DCM algorithm can be applied perfectly. A fiber-optic Michelson interferometric acoustic sensor is fabricated, and an acoustic signal testing system is built to prove the proposed phase demodulation technology. Experimental results show that excellent linearity is observed from 0.033 rad to 3.2 rad. Moreover, the influence of laser wavelength and optical power is researched, and variation below 0.47 dB is observed at different sound pressure levels (SPLs). Long-term stability over thirty minutes is tested, and fluctuation is less than 0.36 dB. The proposed phase demodulation technology obtains large dynamic range and high stability at rather low cost.
提出了一种用于光纤迈克尔逊干涉式传感器的大动态范围和高稳定性相位解调技术。该技术利用一个2×2光纤耦合器的两个输出信号，其干涉相位差为π。采用线性拟合三角恒等变换微分交叉相乘（LF-TIT-DCM）算法从耦合器的两个输出信号中提取相位信号。不同耦合比的2×2光纤耦合器的两个输出信号的干涉相位差均等于π，这确保了LF-TIT-DCM算法能够完美应用。制作了一个光纤迈克尔逊干涉式声学传感器，并搭建了一个声学信号测试系统来验证所提出的相位解调技术。实验结果表明，在0.033 rad至3.2 rad范围内观察到了良好的线性度。此外，研究了激光波长和光功率的影响，在不同声压级（SPL）下观察到变化低于0.47 dB。测试了三十分钟以上的长期稳定性，波动小于0.36 dB。所提出的相位解调技术以相当低的成本获得了大动态范围和高稳定性。
