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

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/degrees 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/degrees 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.