Asymmetric U-Shaped Fiber Taper Probe Based on Polydimethylsiloxane Wrapping for Simultaneous Measurement of Force and Temperature

In this article, an asymmetric U-type fiber taper sensing probe based on polydimethylsiloxane (PDMS) wrapping is presented for simultaneous measurement of the force and the temperature. The asymmetric fiber U-type taper is prepared by using the optical fiber melting technology and is encapsulated in a U-type PDMS. The port diameter and the height of the U-type PDMS are 1 and 1.5 cm, respectively. The asymmetric U-type fiber taper is completely wrapped by the U-type PDMS. Therefore, the proposed fiber sensing probe has a good stability. Multiple interference dips exist in the interference spectrum of the fiber sensing probe with different responses to force and temperature. Detailed shifts of the two interference dips A and B with force and temperature are recorded. The force sensitivities of interference dips A and B are 142.27 and 60.88 nm/N, and the temperature sensitivities are −0.73187 nm/°C and −0.55989 nm/°C, respectively. The fiber sensor probe has good stability, simple preparation process, and low cost; besides, it can effectively avoid the temperature crosstalk in the process of force measurement. Therefore, the proposed asymmetric U-type fiber taper sensing probe has important application prospects in the fields of safety monitoring, aerospace, and medical treatment.