High-Sensitivity Optical Fiber Temperature Sensor Based on Vernier Effect

In this study, we propose a high-sensitive optical fiber temperature sensor that exploits the Vernier effect. The underlying working mechanism of the vernier effect is theoretically analyzed, followed by the theoretical simulation of a tapered single mode-thinned core-single mode fiber (StTS) structural mode. The proposed sensor features a unique structure, consisting of two single-mode fibers seamlessly spliced with a segment of conical small-core-diameter fiber. Through the cascading of StTS structures, the sensor achieves an outstanding sensitivity of 2.02475 nm/°C, with an amplification factor reaching 13.94. Experimental results demonstrate that the sensor exhibits excellent linearity, stability, and repeatability within the temperature range of 22 °C to 46 °C. This design offers significant advantages, including high sensitivity, a straightforward fabrication process, and low cost, making it well-suited for real-time temperature monitoring in both scientific research and practical applications.