High-Resolution Micro-Displacement Measurement using a Fiber MZI Based on Microwave Photonics Filter

In this paper, a high resolution optical fiber micro-displacement measurement system is presented. The sensing signal is interrogated by using a single passband microwave photonic filter (MPF), which mainly consists of a broadband light source, a fiber Mach-Zehnder interferometer (MZI), an electro-optic modulator (EOM) and a long-distance single-mode optical fiber. Since the central frequency of the MPF depends on the FSR of the MZI, the displacement can be estimated by detecting the central frequency shift of the MPF. The proposed approach is experimentally evaluated. High sensitivity displacement sensing with a sensitivity of 2.75 MHz/μm is experimentally demonstrated.