Compact fiber sensor for simultaneous strain and temperature measurement based on malposition splice cascading single-mode-multimode-single-mode fiber grating

Abstract

This paper presents a novel malposition fusion splice cascade single mode, graded index multimode, and single mode fiber (MS-SMS) structure for simultaneous measurement of strain and temperature. The MS-SMS sensor consists of a 4-period single mode fiber graded refractive index multimode fiber splice with a total length of 4.8 mm. Moreover, higher order cladding patterns are excited by malposition fusion splice. The theoretical analysis simulations are in agreement with the experimental results. Experimental validation showed the high strain and temperature sensitivity of the sensor. The sensor has two resonant dips with strain sensitivities of 7.6 pm/με and -8.7 pm/με, respectively. And the sensitivities of the two resonance depressions reached 48 pm/°C and 55.4 pm/°C, respectively.