A novel temperature-insensitive strain sensor, based on an in-line Mach-Zehnder interferometer, is fabricated by concatenating two waist-enlarged fiber tapers separated by a short piece of photonic crystal fiber. The interference spectrum of the proposed sensor is analyzed in detail. Experimental results demonstrate that this sensor has a strain sensitivity of 3.02 pm/\mu \varepsilon and maintains the temperature insensitivity feature. The proposed sensor has great potential in diverse sensing a
