The spectral response of multi-mode interference in optical fibers shows promising application prospects in simultaneous measurement. This paper presents a thin core fiber (TCF) based Mach-Zehnder interferometer (MZI) for simultaneous measurement of temperature and strain. High order cladding modes are excited by splicing a segment of TCF between two single mode fibers (SMFs) with lateral offset. Due to the different spectral responses of the high order cladding modes, the resonant dips in the transmission spectrum are utilized to realize the simultaneous measurement. The sensor is experimentally characterized and the simultaneous measurement is validated. The temperature and strain resolutions of the fabricated sensors are 0.64 degrees C and 5.61 mu epsilon, 0.23 degrees C and 9.14 mu epsilon, 0.21 degrees C and 13.29 mu epsilon, respectively. The maximum strain can be measured is 7000 mu epsilon. The proposed sensor possesses appealing characteristics of easy fabrication, high performance and low cost, and is anticipated to be applied in the structural health monitoring and damage identification.
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