Vernier Effect-Based Strain Sensor With Cascaded Fabry–Perot Interferometers

Highly sensitive cascaded FPI based strain sensor with Vernier Effect is proposed and experimentally demonstrated. This FPI structure is fabricated by simple and cost-effective techniques such as, cleaving, splicing and tapering. Experimental results show that the proposed structure can provide a high strain sensitivity of 37.3 pm/με, that is 13.3 times higher than the sensitivity of the single sensing FPI, which is 2.8 pm/με. Proposed sensor also exhibits very low temperature cross sensitivity of 0.7 pm/C°. This design can provide simple fabrication, stable and linear output response over a large range of applied strain and brings numerous prospects for sensing applications.