In this paper, a polymer micro-Fabry–Pérot interferometer (FPI) fabricated via direct laser writing using two-photon polymerization techniques on a single mode fiber tip is proposed, designed, simulated, and experimentally demonstrated as a magnetic field probe. The sensor comprises a tapered waveguide with a length of 100 µm and a diameter of 1 µm along the axis connecting the two reflecting surfaces of the micro-FPI open cavity. The cavity is filled with a magnetic fluid (MF) changing the evanescent coupling and consequently leading to a change in the phase of the FPI. To improve the signal reflection, a thin layer of Au is coated on the device before fabricating the probe sensor, which is then sealed in a MF-filled glass tube. The experimental results show that the proposed probe sensor has a low temperature sensitivity and a sensitivity to magnetic field as high as 1.54 nm/mT, and the magnetic field measurement accuracy is ∼649.4 $\mu$T within a range from 1 mT to 8 mT. The microsensor, which is very stable and easy to fabricate, can be used as a probe to detect weak magnetic fields.

中文翻译：

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基于光纤尖端法布里-珀罗腔光纤直接激光写入的高灵敏度磁场微传感器

在本文中，提出，设计，模拟并通过实验证明了通过在单模光纤尖端上使用双光子聚合技术通过直接激光写入使用双光子聚合技术制造的聚合物微法布里-珀罗干涉仪（FPI）。该传感器包括具有100的长度的锥形波导μ m和一个直径为1的μ沿着连接微型FPI敞开腔的两个反射面的轴m。空腔中充满了磁性流体（MF），从而改变了瞬逝耦合，从而导致FPI相位发生变化。为了改善信号反射，在制造探针传感器之前，先在设备上涂覆一层Au薄层，然后将其密封在MF填充的玻璃管中。实验结果表明，所提出的探头传感器具有较低的温度灵敏度，对磁场的灵敏度高达1.54 nm / mT，磁场测量精度约为649.4。$\mu$T在1 mT至8 mT的范围内。微型传感器非常稳定且易于制造，可用作探测弱磁场的探针。