Highly Efficient D-type Photonic Crystal Fiber Surface Plasmon Resonance Sensor for Same Space–Time Temperature and Refractive Index Detection

In order to realize temperature and refractive index (RI) detection of the analyte in the same space–time, a dual parameter detection photonic crystal fiber (PCF) optical sensor is proposed in this paper. Meanwhile, it can effectively avoid the interference of analyte temperature with RI detection. Furthermore, a dual polished D-type structure is designed to provide mutually independent detection channels for temperature and RI, respectively. In addition, silver is used as the metal layer material, and polydimethylsiloxane (PDMS) and titanium dioxide (TiO2) are used as the temperature-sensitive materials and RI-sensitive materials, respectively. This structure design enables the two detection results to be output in parallel without interfering with each other. The proposed optical fiber sensor has a wide detection range and good detection performance. The temperature detection range can be as wide as −60 to 100°C, and the RI detection range is 1.30–1.40. The best temperature resolution can be 1.42 × 10−2 RIU, and the temperature wavelength sensitivity is 0.7 nm/°C. While the RI wavelength sensitivity is up to 1.25 × 104 nm/RIU, and the wavelength resolution is 8 × 10− 6 RIU. The detailed fabrication process of the sensor is given in this paper, as well as the practical application scenarios. Therefore, the optical fiber sensor proposed in this paper has research significance for the development of dual parameter detection optical fiber sensors.