A fiber liquid level temperature sensor based on fiber Mach-Zehnder interferometer(MZI)is designed and fabricated in this paper.The structure is composed of a no-core fiber(NCF)and a multi-mode fiber(MMF)fused between single-mode fibers(SMFs).The change of ambient liquid level and temperature will lead to the change of optical transmission mode of the interferometer,and then cause the movement of interference spectrum fringe.The sensitivity of liquid level and temperature response can be obtained by detecting the drift of wavelength of two valleys in the interference spectrum.The sensitivity coefficient matrix can be used to measure liquid level and temperature simultaneously.The re-sults show that the interference spectrum is red shifted when the liquid level rises.The maximum liquid level response sensitivity is 208.38 pm/mm in the range of 0-36 mm level variation.When the tem-perature increases,the interference spectrum still keeps red shift.The maximum temperature response sensitivity is 29.67 pm/℃ in the range of 30-70 ℃.The sensor structure has the advantages of high sensitivity,large measuring range,simple manufacturing,low cost and simultaneous measurement of liq-uid level temperature,etc.,which has the potential application in the sensing field.
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