Vernier-effect-based C-shaped fiber sensor for temperature measurement

In this paper, we propose a Vernier effect-based fiber-optic temperature sensor. The structure of the sensor is fabricated by cascading a single mode fiber (SMF) pigtail together with a C-shaped fiber segment and another SMF segment. In this original sensing architecture, the C-shaped fiber segment constitutes a Fabry-Perot interferometer (FPI) used as a sensing cavity while the SMF segment serves as a reference cavity. These two cavities have a slightly different optical path length to trigger the Vernier effect. Both theoretical calculations and experiments are carried out in the characterization of the sensor measuring temperature. The experimental sensitivity of the sensor is found to be -9.15 nm/°C for temperature measurement.