Abstract:A temperature-insensitive micro-displacement sensor based on a spindle-shaped single mode fiber (SMF) is presented and demonstrated. The SMF is bent into a balloon-shaped SMF and burned into a spindle-shaped SMF by a flame. Due to the bending of the fiber, part of the incident light leaks from the fiber core into the fiber cladding, which excites higher order cladding modes. Therefore, modal interference occurs. The experimental results show that the maximum sensitivity of the sensors is -203 pm/μm when micro-displacement varies from 0 to 80 μm. The sensors are insensitive to temperature in the range of 20-70℃. In addition, the sensors have advantages of simple structure, low cost, small volume, high sensitivity and stability, which can be widely used in numerous high-precision industrial measurements and civil engineering structure monitoring fields.