High Sensitive Micro-Displacement Sensor Based on M-Z Interferometer by a Bowknot Type Taper

A simple, compact, and high sensitive optical fiber Mach-Zehnder interferometer (MZI) based micro-displacement sensor is presented. The MZI is fabricated by a core offset connecting of two single mode fibers and bowknot-type taper. The shifts of the MZI transmission spectrum correspond to the micro-displacements on the cross section of the core offset. For the micro-displacement ranging from 0 to 13 μm, the proposed sensor shows a high sensitivity of -1.89 dB/μm, which is almost 787 times higher than that of the current similar existing micro-displacement sensor. In addition by using the intensity demodulation method, the proposed sensor can overcome the temperature and displacement cross-sensitivity effects.