Ultra-wide range and high-sensitivity temperature sensor based on a simple SPR system

In this work, a temperature sensor is proposed and experimentally demonstrated using a low cost surface plasmon resonance (SPR) system based on optical fiber. The sensor is formed by splicing a short length of no-core fiber (NCF) with two multimode fibers (MMFs). A silver film is deposited on the NCF to excite SPR effect. Overcome the defect of the complex fabrication process of the existing optical fiber sensor. The sensing characteristics at different deposition times have been studied. Experimental results show that for low and medium–high temperature, the sensitivity of the sensor is −3.01 and −1.425 nm/°C, respectively. It has a wide detection range from −40 to + 70 °C. The sensor also showed good reliability after repeated experiments. The temperature sensor covering low and medium–high temperature has important application value in agricultural production and soil temperature monitoring.