High-sensitive Mach-Zehnder interferometric temperature fiber-optic sensor based on core-offset splicing technique

•The sensor's temperature sensitivity is 660 times in magnitude of the unfilled MZI.•The sensitivity could be further enhanced by using liquid with appropriate parameter.•Temperature compensated could be realized by using liquid with small thermo-optic coefficient. We demonstrated a high-sensitive Mach-Zehnder interferometric temperature fiber-optic sensor based on core-offset splicing technique by filling the interferometer with refractive index matching liquid. The fiber-optic interferometer was constructed of a section of quartz capillary sandwiched by two core-offset spliced optical fibers, and its sensitivities to external refractive index and temperature were −17335 nm/RIU and 32 pm/°C, respectively. When the quartz capillary of the interferometer was filled with the above liquid, the sensor was highly sensitive to temperature due to the thermo-optic effect. A sensitivity of 21.2 nm/°C which is 660 times in magnitude of the unfilled Mach-Zehnder interferometer was achieved. The proposed sensor’s excellent compactness, simple fabrication process and high sensitivity will be their advantages of future applications in security fields, industrial areas and biomedical detection.