Simultaneous Measurement of Temperature and Transversal Loading by Using a Modified Fiber Mach-Zehnder Interferometer

In this paper, a fiber-optic sensing interrogation system for simultaneous measurement of temperature and transversal loading based on a modified fiber Mach-Zehnder interferometer (FMZI) has been theoretically and experimentally demonstrated. In our experiment, the modified FMZI is taken as the sensing element as well as the spectrum slicer for a dual-passband microwave photonic filter (MPF). One arm of the FMZI is used as the temperature sensing fiber, and portion of the fiber in the second loop of the FMZI is utilized for measuring the transversal loading variation. As the temperature increases, the central frequencies of the passbands of the MPF move to the higher frequency. The peak amplitude of the lower passband decreases while the higher one increases with the increment of transversal loading. Thus, simultaneous measurement of temperature and transversal loading can be implemented by tracking the central frequencies and the peak amplitude of the passbands.