超磁致伸缩薄膜/光纤的制备及其磁探测性能

Preparation and magnetic field detection properties of giant magnetostrictive thin film/optical fibre

采用磁控溅射工艺在光纤表面制备了厚度均匀的TbDyFe超磁致伸缩薄膜。利用马赫 曾德尔干涉仪对TbDyFe超磁致伸缩薄膜/光纤传感器的磁探测性能进行了实验测试。结果表明:在调制频率f=1kHz附近,传感器对磁场具有最大的信号响应;在恒定直流磁场及调制磁场强度小于1kA/m的条件下,输出信号大小随调制磁场强度线性增加;在35～50kA/m的直流磁场范围内,传感器(对应1m长传感臂)可探测的最小磁场变化Hmin=8.6×10-2A/m,若采用分辨力为10-6rad的干涉仪并增加镀膜光纤的长度和薄膜厚度,则可进一步提高传感器的磁探测灵敏度。

Giant magnetostrictive TbDyFe film on the surface of optical fibre is prepared by magnetron sputtering.And the film is even in thickness.Magnetic field detection properties of giant magnetostrictive FbDyFe thin film and optical fibre magnetic field sensor are tested from experiment by using a Mach-Zehnder interferometer.It is revealed that the sensor exhibits the largest responses against applied magnetic fields at the frequency of about (1 kHz).When the DC magnetic field is maintained at a fixed value,there is a good linearity between the output signal and the AC magnetic field which is below 1 kA/m.Minimum detectable field of 8.6×10^(-2)A/m is demonstrated over a range of 35 kA/m to 50 kA/m for the DC bias magnetic field for a l m long fibre coated with TbDyFe film.And sensitivity of magnetic fields detection of the sensor is improved by using the interferometer with the resolution in 10^(-6)rad and the longer optical fibre coated with thicker TbDyFe film.