Assembly-free ultra-sensitive miniaturized strain sensor based on an asymmetric optical fiber taper

This research reports an ultra-sensitive miniaturized optical fiber strain sensor based on a one-step assembly-free structure. A 10 µm thin asymmetrical taper waist of a single mode fiber (SMF) was designed and fabricated to form a Michelson Interferometer (MI). The sensor has been experimentally demonstrated for strain measurements with long-term stability. The sensor provides a ∼14 dB fringe visibility with a high extinction ratio in the reflection spectrum. Experimental results indicate that the sensor exhibits maximum strain sensitivity of −39.77 pm/µε in the measurement range of 0 to 1600 µε. The sensor shows promising results in terms of stability and repeatability. The proposed sensor requires only one-step fabrication with great reproducibility and, therefore, can be easily mass-produced with a less stringent requirement in fabrication equipment. A highly sensitive response for measuring axial strain makes the sensor a viable contender for a number of specialized niche applications.