LAUSR

In this article, a cascaded all-fiber structure is proposed and demonstrated, which includes sensing Mach–Zehnder interferometer (SMZI) based on a joint-assisted open-cavity and referencing Fabry–Perot interferometer (RFPI) based on hollow-core fiber (HCF). The temperature sensitivity of SMZI is well guaranteed and greatly improved by the Vernier effect, while the axial-strain crosstalk is obviously compressed by lengthening the open cavity to $\sim 2600~\mu \text{m}$ . Experimental results show that, with magnification factor of 19.04, the temperature response reaches 1.525 nm/° and the cross sensitivity is smaller than $0.02~^{\circ }\text{C}/\mu \varepsilon $ . Additionally, rapid time responses of less than 0.8 s are verified in the field tests of respiratory and gas lighter. The proposed scheme presents the capability to achieve the high-precision temperature-related engineering sensing and monitoring.