Mach-Zehnder干涉仪型光纤应变传感器

A Mach-Zehnder Fiber-optic Interferometric Strain Sensor

研制了一种Mach-Zehnder干涉仪型光纤应变传感器,首次把光纤用于纵向应变的测量。计算和测量了光纤应变传感器的灵敏度、温度特性和偏振特性。理论与实验符合。实验结果表明,光纤护套对应变测量有增敏作用,温度特性方面也存在类似的效应。分析了光源稳定性和环境干扰因素对传感器的影响,结果表明这些影响是不容忽视的,它们甚至最终限制了光纤应变传感器的灵敏度。在被测应变的动态范围不大时,利用李萨如图法记录干涉条纹的移动,既能记录其移动的数目,也能表示其移动的方向。在对光纤的偏振特性进行分析的基础上,把1/4波片与偏振器组合使用,可明显提高干涉条纹的可见度。

A Mach-Zehnder fiber-optic interferometric strainsenso ris described.The single-mode optical fiber is used to detect longitudinal strain.The sensi-tivity and the temperature as well as polarization characteristics of the strainsensor are calculated and measured.The results demenstrated that the plastics jack-et of fibers makes the strain(?)sensor more sensitive to strain and temperature.Theeffects of the stability of laser sourses and environmentaI factors on fiber-opticstrain sensor are analysed.It is shown that these effects are unnegnigibie andeven limit the sensitivity of the strain sensor ultimately.when the dynamic range ofthe strain is small,Lissajous′ figur(?)smethod can be used to record the number anddirection of the moving interference fringes.Based on the Polarization analysis offibers,λ/4 plates and polarizers are used to enhance the visibility of interferencefringes.